Method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining

Abstract

The invention relates to a method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining, and belongs to the technical field of titanium-aluminum alloys. The method comprises the following steps of pre-treating raw materials, weighing the raw materials in the mass ratio of rutile or high-titanium slags or titanium dioxide to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:(0.60-0.24):(0.042-0.048):(0.12-0.26):(0.22-0.30), performing an aluminothermic self-propagating reaction in a gradient feeding manner to obtain high-temperature melt, performing a gradient reduction melting, performing heat insulation and separating the melt after the feeding is completed, then adding CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags into the high-temperature melt, performing slag washing refining, and finally removing slags to obtain titanium alloys. This method has the advantages including short flow, low energy consumption, easy operation, easy control on Al and V contained in alloys, and so on.

Claims

1. A method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining, comprising the following steps: Step 1: material pre-treatment pre-treating aluminothermic reduction reaction materials separately to obtain pre-treated aluminothermic reduction reaction materials, wherein the aluminothermic reduction reaction materials include titanium-containing material, aluminum powder, V.sub.2O.sub.5 powder, CaO and KClO.sub.3, the titanium-containing material is at least one selected from the group consisting of rutile, titanium slags and titanium dioxide; weighing the pre-treated aluminothermic reduction reaction materials with a proportional ratio, wherein the proportional ratio is a mass ratio of titanium-containing material:aluminum powder:V.sub.2O.sub.5 powder:CaO:KClO.sub.3 being 1.0:(0.60-0.24):(0.042-0.048):(0.12-0.26):(0.22-0.30), respectively; wherein a particle size of the pre-treated aluminothermic reduction reaction materials is as follow: rutile and titanium slags no larger than 3 mm, titanium dioxide no larger than 0.02 mm, and aluminum powder, V.sub.2O.sub.5 powder, CaO and KClO.sub.3 no larger than 2 mm, 0.2 mm, 0.2 mm and 2 mm, respectively; Step 2: aluminothermic self-propagating reaction performing gradient aluminothermic reduction with one of the two following feeding manners: feeding manner I: mixing the weighed aluminothermic self-propagating reaction materials other than aluminum powder uniformly to obtain a material mixture, and dividing the material mixture into several parts; then assigning aluminum powder to each part of the material mixture according to a sequence of each part of the material mixture being fed into a reaction furnace, and gradually reducing the amount of aluminium powder assigned from 1.15-1.35 times the stoichiometric ratio to 0.85-0.65 times the stoichiometric ratio; wherein the mass of a part of the material mixture that is fed into the reaction furnace as a first batch accounts for 10-30% of the mass of the total material mixture, the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt, that is sufficient to initiate subsequent reactions, is obtained; feeding other parts of the material mixture into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials are fully reacted to obtain a high-temperature melt; or feeding manner II: mixing the aluminothermic self-propagating reaction materials other than aluminum powder uniformly to obtain a material mixture, and then feeding the material mixture into a continuous material mixer at a constant flow rate; at the same time, adding aluminum powder into the continuous material mixer at a flow rate with reduced gradient, so that the amount of aluminium powder assigned to the continuously fed material mixture is gradually reduced from 1.15-1.35 times the stoichiometric ratio to 0.85-0.65 times the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminium powder assigned conforms the following formula:
m=(bc)a(1); wherein, m is the times of gradient changes of the amount of aluminum powder assigned, b is the maximum amount of aluminum powder assigned, c is the minimum amount of aluminum powder assigned, a represents a coefficient for gradient changes of the amount of aluminum powder assigned, and 0<a0.04; mixing the aluminothermic self-propagating reaction materials uniformly in the continuous material mixer, and continuously feeding the material mixture into the reaction furnace for aluminothermic reduction until all material are fully reacted to obtain a high-temperature melt; Step 3: melt separation under electromagnetic field heating the high-temperature melt through electromagnetic induction to perform heat insulation and melt separation, and realize slag-metal separation to obtain a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt, wherein the temperature is controlled within the range of 1700-1800 C. and the heat insulation time is 5-25 minutes in the melt separation process; Step 4: slag washing refining (1) removing 85-95% of the total volume of the aluminum oxide based melt slags at the upper layer, stirring the remaining aluminum oxide based melt slags and the alloy melt at the lower layer by an eccentrically mechanical stirring at a stirring speed of 50-150 rpm under a temperature range of 17001800 C.; (2) after the melt being uniformly mixed, continuously stirring, meanwhile, spraying and blowing CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags into the uniformly-mixed melt with inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials in the weighing step to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:(0.02-0.08); the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags comprise the following chemical ingredients and mass percentages: 5%-10% of CaF.sub.2, 40%-60% of CaO, 0-2% of Na.sub.2O, 30%-40% of TiO.sub.2, 5%-15% of V.sub.2O.sub.5 and the balance being inevitable impurities, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm; and (3) after spraying and blowing the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags, performing heat insulation at 1700-1800 C. and continuously stirring with the eccentrically mechanical stirring for 10-30 minutes, so as to obtain a titanium alloy melt; and Step 5: cooling cooling the titanium alloy melt to room temperature, and then removing the melting slags on a top to obtain titanium alloys.

2. The method according to claim 1, wherein the prepared titanium alloys comprise the following chemical ingredients and mass percentages: 5.5%-6.5% of Al, 3.5%-4.5% of V, 0.2%-1.0% of Si, 0.2%-1.0% of Fe, O0.9%, and the balance being Ti.

3. The method according to claim 1, wherein in the step 1, the aluminothermic reduction reaction materials are pre-treated separately by the following steps: (1) roasting the titanium-containing material, V.sub.2O.sub.5 powder and CaO individually at a temperature no less than 120 C. for 12-36 hours; and (2) drying KClO.sub.3 at 150-300 C. for 12-48 hours.

4. The method according to claim 1, wherein in the step 2, the number of the several parts is n, wherein n is no less than 4.

5. The method according to claim 1, wherein in the step 3, an equipment for electromagnetic induction is a medium-frequency induction furnace, and the frequency of the electromagnetic field is no less than 1000 Hz.

6. The method according to claim 1, wherein in the step 4, an eccentricity of the eccentrically mechanical stirring is 0.2-0.4.

7. The method according to claim 1, wherein in the step 4, the spraying and blowing are performed at a bottom of the medium-frequency induction furnace.

8. The method according to claim 1, wherein in the step 4, the inert gas is argon, and the purity is no less than 99.95%.

9. The method according to claim 1, wherein in the step 4(2), the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags are pre-treated before being used, under a roasting temperature of 150-450 C. for a roasting time of 10-48 hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention is further described as below in corporation with embodiments.

(2) In the following embodiments:

(3) In the titanium-containing materials: rutile contains a mass percentage of TiO.sub.292% and the balance being impurities, the particle size of rutile being no larger than 3 mm; high-titanium slags contain a mass percentage of TiO.sub.292% and the balance being impurities, the particle size of high-titanium slags being no larger than 3 mm; titanium dioxide contains a mass percentage of TiO.sub.299.5% and the balance being impurities, the particle size of titanium dioxide being no larger than 0.02 mm.

(4) The particle size of V.sub.2O.sub.5 powder is no larger than 0.2 mm.

(5) The particle size of aluminum powder is no larger than 2 mm.

(6) The particle size of a slag forming agent is no larger than 0.2 mm.

(7) The purity of high purity argon is greater than 99.95%.

(8) In the following embodiments, a medium frequency induction furnace is adopted as an equipment in the melt separation and the slag washing refining process. The frequency of the electromagnetic field in the medium-frequency induction furnace is not lower than 1000 Hz.

Embodiment 1

(9) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(10) Step 1: Material Pre-Treatment

(11) Aluminothermic reduction reaction materials were pre-treated separately. In particular, high-titanium slags in which the mass percentage of TiO.sub.2 is 92% and V.sub.2O.sub.5 powder were roasted separately at 600 C. for 32 hours, CaO was roasted at 200 C. for 16 hours, and KClO.sub.3 was dried at 160 C. for 18 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(12) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of high-titanium slags to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(13) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: the high-titanium slags are no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(14) Step 2: Aluminothermic Self-Propagating Reaction

(15) The weighed aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, the material mixture was divided into 5 parts.

(16) Aluminum powder was assigned to each part of the material mixture according to the sequence of each part of the material mixture fed into a reaction furnace, wherein the amount of aluminium powder assigned is sequentially 1.20, 1.05, 1.0, 0.90 and 0.85 times of the stoichiometric ratio. The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t95%.

(17) Wherein the mass of a part of the material mixture that was fed into the reaction furnace as a first batch accounts for 20% of the mass of the total material mixture, and the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt that is sufficient to initiate subsequent reactions was obtained.

(18) After that, other parts of the material mixture were sequentially fed into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials were fully reacted to obtain high-temperature melt.

(19) Step 3: Melt Separation Under Electromagnetic Field

(20) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1800 C. and the heat insulation time was 15 minutes in the melt separation process.

(21) Step 4: Slag Washing Refining

(22) (1) 90% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.3 and at a stirring speed of 50 rpm under a temperature of 1800 C.

(23) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.02.

(24) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 60% of CaO, 0% of Na.sub.2O, 30% of TiO.sub.2, and 5% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 150 C. for 10 hours.

(25) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1800 C. is kept and the continuously eccentrically mechanical stirring are performed for 10 minutes, and then stopped to obtain titanium alloy melt.

(26) Step 5: Cooling

(27) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(28) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 6.2% of Al, 3.50% of V, 0.2% of Si, 0.2% of Fe, 0.32% of O, and the balance being Ti.

Embodiment 2

(29) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(30) Step 1: Material Pre-Treatment

(31) Aluminothermic reduction reaction materials were pre-treated separately. In particular, titanium dioxide containing a mass percentage of 99.5% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 650 C. for 36 hours, CaO was roasted at 200 C. for 8 hours, and KClO.sub.3 were dried at 160 C. for 18 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(32) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of titanium dioxide to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(33) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: titanium dioxide is no larger than 0.02 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(34) Step 2: Aluminothermic Self-Propagating Reaction

(35) The weighed aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, the material mixture was divided into 6 parts.

(36) Aluminum powder was assigned to each part of the material mixture according to the sequence of each part of the material mixture fed into a reaction furnace, wherein the amount of aluminium powder assigned is sequentially 1.20, 1.1, 0.95, 0.90, 0.85 and 0.80 times of the stoichiometric ratio. The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t98%.

(37) Wherein the mass of a part of the material mixture that was fed into the reaction furnace as a first batch accounts for 28.6% of the mass of the total material mixture, and the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt that is sufficient to initiate subsequent reactions was obtained.

(38) After that, other parts of the material mixture were sequentially fed into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials were fully reacted to obtain high-temperature melt.

(39) Step 3: Melt Separation Under Electromagnetic Field

(40) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1750 C. and the heat insulation time was 20 minutes in the melt separation process.

(41) Step 4: Slag Washing Refining

(42) (1) 95% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.2 and at a stirring speed of 100 rpm under a temperature of 1750 C.

(43) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.04.

(44) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 10% of CaF.sub.2, 50% of CaO, 0% of Na.sub.2O, 30% of TiO.sub.2, and 10% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 150 C. for 20 hours.

(45) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1750 C. is kept, and the continuously eccentrically mechanical stirring is performed for 30 minutes, and then stopped to obtain titanium alloy melt.

(46) Step 5: Cooling

(47) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(48) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 6.0% of Al, 3.80% of V, 0.3% of Si, 0.6% of Fe, 0.24% of O and the balance being Ti.

Embodiment 3

(49) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(50) Step 1: Material Pre-Treatment

(51) Aluminothermic reduction reaction materials were pre-treated separately. In particular, rutile containing a mass percentage of 92% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 600 C. for 24 hours, CaO was roasted at 300 C. for 12 hours, and KClO.sub.3 was dried at 200 C. for 18 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(52) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of rutile to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(53) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: rutile is no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(54) Step 2: Aluminothermic Self-Propagating Reaction

(55) The weighed aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, the material mixture was divided into 8 parts.

(56) Aluminum powder was assigned to each part of the material mixture according to the sequence of each part of the material mixture fed into a reaction furnace, wherein the amount of aluminium powder assigned is sequentially 1.20, 1.1, 1.0, 0.95, 0.925, 0.90, 0.875 and 0.85 times of the stoichiometric ratio. The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t99%.

(57) Wherein the mass of a part of the material mixture that was fed into the reaction furnace as a first batch accounts for 22.2% of the mass of the total material mixture, and the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt that is sufficient to initiate subsequent reactions was obtained.

(58) After that, other parts of the material mixture were sequentially fed into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials were fully reacted to obtain high-temperature melt.

(59) Step 3: Melt Separation Under Electromagnetic Field

(60) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1700 C. and the heat insulation time was 25 minutes in the melt separation process.

(61) Step 4: Slag Washing Refining

(62) (1) 95% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentric mechanical stirring with an eccentricity of 0.2 and at a stirring speed of 100 rpm under a temperature of 1700 C.

(63) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.06.

(64) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 40% of CaO, 0% of Na.sub.2O, 40% of TiO.sub.2, and 15% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 180 C. for 20 hours.

(65) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1700 C. is kept, and the continuously eccentrically mechanical stirring is performed for 30 minutes, and then stopped to obtain titanium alloy melt.

(66) Step 5: Cooling

(67) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(68) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.8% of Al, 4.40% of V, 0.4% of Si, 0.8% of Fe, 0.2% of O and the balance being Ti.

Embodiment 4

(69) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(70) Step 1: Material Pre-Treatment

(71) Aluminothermic reduction reaction materials were pre-treated separately. In particular, high-titanium slags containing a mass percentage of 93% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 700 C. for 12 hours, CaO was roasted at 300 C. for 36 hours, and KClO.sub.3 was dried at 250 C. for 8 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(72) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of high-titanium slags to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(73) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: high-titanium slags are no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(74) Step 2: Aluminothermic Self-Propagating Reaction

(75) The aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, and the material mixture was fed into a continuous material mixer at a constant flow rate.

(76) Besides, aluminum powder was added into the continuous material mixer at a flow rate with reduced gradient so that the amount of aluminum powder assigned to the continuously fed material mixture is gradually reduced from 1.28 times of the stoichiometric ratio to 0.7 times of the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminum powder assigned conforms the following relational formula:
m=(bc)a(1).

(77) In the formula, m is the times of gradient changes of the amount of aluminium powder assigned, b is the maximum amount of aluminium powder assigned, c is the minimum amount of aluminium powder assigned, a represents a coefficient for gradient changes of the amount of aluminium powder assigned, where a is equal to 0.01. Through calculation, m is 58 times, and the time interval between gradient changes of the flow of aluminum powder is the total reaction time divided by m.

(78) The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein:
m.sub.a=m.sub.t98%.

(79) The aluminothermic self-propagating reaction materials were mixed uniformly in the continuous material mixer, and were continuously fed into the reaction furnace for aluminothermic reduction reaction until all materials were fully reacted to obtain high-temperature melt.

(80) Step 3: Melt Separation Under Electromagnetic Field

(81) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1800 C. and the heat insulation time was 15 minutes in the melt separation process.

(82) Step 4: Slag Washing Refining

(83) (1) 85% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentric mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 50 rpm under a temperature of 1800 C.

(84) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.00.05.

(85) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 10% of CaF.sub.2, 50% of CaO, 0% of Na.sub.2O, 35% of TiO.sub.2, and 5% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 150 C. for 10 hours.

(86) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1800 C. is kept, and the continuously eccentrically mechanical stirring is performed for 20 minutes, and then stopped to obtain titanium alloy melt.

(87) Step 5: Cooling

(88) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(89) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 6.1% of Al, 3.60% of V, 0.6% of Si, 0.7% of Fe, 0.31% of O and the balance being Ti.

Embodiment 5

(90) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(91) Step 1: Material Pre-Treatment

(92) Aluminothermic reduction reaction materials were pre-treated separately. In particular, high-titanium slags containing a mass percentage of 92.5% of TiO.sub.2, titanium dioxide containing a mass percentage of 99.6% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 650 C. for 20 hours, CaO was roasted at 200 C. for 12 hours, and KClO.sub.3 was dried at 150 C. for 18 hours, to obtain pre-treated aluminothermic reduction reaction materials, wherein the mixing mass ratio of high-titanium slags to titanium dioxide is 1 to 1.

(93) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of high-titanium slags and titanium dioxide to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(94) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: high-titanium slags is no larger than 3 mm, titanium dioxide is no larger than 0.02 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(95) Step 2: Aluminothermic Self-Propagating Reaction

(96) The aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, and the material mixture was fed into a continuous material mixer at a constant flow rate.

(97) Besides, aluminum powder was added into the continuous material mixer at a flow rate with reduced gradient so that the amount of aluminum powder assigned to the continuously fed material mixture is gradually reduced from 1.20 times of the stoichiometric ratio to 0.75 times of the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminum powder assigned conforms the following relational formula:
m=(bc)a(1).

(98) In the formula, m is the times of gradient changes of the amount of aluminium powder assigned, b is the maximum amount of aluminium powder assigned, c is the minimum amount of aluminium powder assigned, a represents a coefficient for gradient changes of the amount of aluminium powder assigned, where a is equal to 0.003. Through calculation, m is 150 times.

(99) The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein:
m.sub.a=m.sub.t96%.

(100) The aluminothermic self-propagating reaction materials were mixed uniformly in the continuous material mixer, and were continuously fed into the reaction furnace for aluminothermic reduction reaction until all materials were fully reacted to obtain high-temperature melt.

(101) Step 3: Melt Separation Under Electromagnetic Field

(102) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1700 C. and the heat insulation time was 15 minutes in the melt separation process.

(103) Step 4: Slag Washing Refining

(104) (1) 90% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 150 rpm under a temperature of 1700 C.

(105) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.05.

(106) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 50% of CaO, 0% of Na.sub.2O, 30% of TiO.sub.2, and 10% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 450 C. for 12 hours.

(107) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1700 C. is kept, and the continuously eccentrically mechanical stirring is performed for 10 minutes, and then stopped to obtain titanium alloy melt.

(108) Step 5: Cooling

(109) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(110) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.8% of Al, 4.10% of V, 0.3% of Si, 0.6% of Fe, 0.22% of O and the balance being Ti.

Embodiment 6

(111) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(112) Step 1: Material Pre-Treatment

(113) Aluminothermic reduction reaction materials were pre-treated separately. In particular, high-titanium slags containing a mass percentage of 93% of TiO.sub.2, titanium dioxide containing a mass percentage of 99.5% of TiO.sub.2, rutile containing a mass percentage of 94% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 650 C. for 36 hours, CaO was roasted at 300 C. for 16 hours, and KClO.sub.3 was dried at 180 C. for 24 hours, to obtain pre-treated aluminothermic reduction reaction materials, wherein the mixing mass ratio of high-titanium slags to titanium dioxide to rutile is 1 to 1 to 1.

(114) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of high-titanium slags and titanium dioxide and rutile to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(115) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: high-titanium slags are no larger than 3 mm, rutile is no larger than 3 mm, titanium dioxide is no larger than 0.02 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(116) Step 2: Aluminothermic Self-Propagating Reaction

(117) The aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, and the material mixture was fed into a continuous material mixer at a constant flow rate.

(118) Besides, aluminum powder were added into the continuous material mixer at a flow rate with reduced gradient so that the amount of aluminum powder assigned to the continuously fed material mixture is gradually reduced from 1.2 times of the stoichiometric ratio to 0.75 times of the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminum powder assigned conforms the following relational formula:
m=(bc)a(1).

(119) In the formula, m is the times of gradient changes of the amount of aluminium powder assigned, b is the maximum amount of aluminium powder assigned, c is the minimum amount of aluminium powder assigned, a represents a coefficient for gradient changes of the amount of aluminium powder assigned, where a is equal to 0.001. Through calculation, m is 450 times.

(120) The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein:
m.sub.a=m.sub.t95%.

(121) The aluminothermic self-propagating reaction materials were mixed uniformly in the continuous material mixer, and were continuously fed into the reaction furnace for aluminothermic reduction reaction until all materials were fully reacted to obtain high-temperature melt.

(122) Step 3: Melt Separation Under Electromagnetic Field

(123) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, and thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1750 C. and the heat insulation time was 20 minutes in the melt separation process.

(124) Step 4: Slag Washing Refining

(125) (1) 90% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 50 rpm under a temperature of 1750 C.

(126) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.06.

(127) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 10% of CaF.sub.2, 40% of CaO, 0% of Na.sub.2O, 35% of TiO.sub.2, and 15% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 200 C. for 12 hours.

(128) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1750 C. is kept, and the continuously eccentrically mechanical stirring is performed for 30 minutes, and then stopped to obtain titanium alloy melt.

(129) Step 5: Cooling

(130) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(131) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.6% of Al, 4.40% of V, 0.6% of Si, 0.8% of Fe, 0.18% of O and the balance being Ti.

Embodiment 7

(132) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(133) Step 1: Material Pre-Treatment

(134) Aluminothermic reduction reaction materials were pre-treated separately. In particular, rutile containing a mass percentage of 92% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 600 C. for 24 hours, CaO was roasted at 200 C. for 16 hours, and KClO.sub.3 was dried at 180 C. for 20 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(135) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of rutile to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(136) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: rutile is no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(137) Step 2: Aluminothermic Self-Propagating Reaction

(138) The weighed aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, the material mixture was divided into 5 parts.

(139) Aluminum powder was assigned to each part of the material mixture according to the sequence of each part of the material mixture fed into a reaction furnace, wherein the amount of aluminium powder assigned is sequentially 1.20, 1.05, 1.0, 0.90 and 0.85 times of the stoichiometric ratio. The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t98%.

(140) Wherein the mass of a part of the material mixture that was fed into the reaction furnace as a first batch accounts for 20% of the mass of the total material mixture, and the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt that is sufficient to initiate subsequent reactions was obtained.

(141) After that, other parts of the material mixture were sequentially fed into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials were fully reacted to obtain high-temperature melt.

(142) Step 3: Melt Separation Under Electromagnetic Field

(143) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1700 C. and the heat insulation time was 15 minutes in the melt separation process.

(144) Step 4: Slag Washing Refining

(145) (1) 90% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.3 and at a stirring speed of 100 rpm under a temperature of 1700 C.

(146) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.04.

(147) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 50% of CaO, 0% of Na.sub.2O, 40% of TiO.sub.2, and 5% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 150 C. for 10 hours.

(148) (3) After s the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1700 C. is kept, and the continuously eccentrically mechanical stirring is performed for 10 minutes, and then stopped to obtain titanium alloy melt.

(149) Step 5: Cooling

(150) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(151) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 6.3% of Al, 3.70% of V, 0.4% of Si, 0.6% of Fe, 0.35% of O and the balance being Ti.

Embodiment 8

(152) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(153) Step 1: Material Pre-Treatment

(154) Aluminothermic reduction reaction materials were pre-treated separately. In particular, titanium dioxide containing a mass percentage of 99.7% of TiO.sub.2, rutile containing a mass percentage of 93% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 700 C. for 16 hours, CaO was roasted at 250 C. for 16 hours, and KClO.sub.3 was dried at 180 C. for 36 hours, to obtain pre-treated aluminothermic reduction reaction materials, wherein the mixing mass ratio of titanium dioxide to the rutile is 1 to 1.

(155) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of titanium dioxide and rutile to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(156) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: titanium dioxide is no larger than 0.02 mm, rutile is no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(157) Step 2: Aluminothermic Self-Propagating Reaction

(158) The weighed aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, the material mixture was divided into 6 parts.

(159) Aluminum powder was assigned to each part of the material mixture according to the sequence of each part of the material mixture fed into a reaction furnace, wherein the amount of aluminium powder assigned is sequentially 1.20, 1.1, 0.95, 0.90, 0.85 and 0.80 times of the stoichiometric ratio. The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t98%.

(160) Wherein the mass of a part of the material mixture that was fed into the reaction furnace as a first batch accounts for 28.6% of the mass of the total material mixture, and the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt that is sufficient to initiate subsequent reactions was obtained.

(161) After that, other parts of the material mixture were sequentially fed into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials were fully reacted to obtain high-temperature melt.

(162) Step 3: Melt Separation Under Electromagnetic Field

(163) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1800 C. and the heat insulation time was 15 minutes in the melt separation process.

(164) Step 4: Slag Washing Refining

(165) (1) 95% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 50 rpm under a temperature of 1800 C.

(166) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.06.

(167) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 10% of CaF.sub.2, 40% of CaO, 0% of Na.sub.2O, 40% of TiO.sub.2, and 10% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 150 C. for 48 hours.

(168) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1800 C. is kept, and the continuously eccentrically mechanical stirring is performed for 20 minutes, and then stopped to obtain titanium alloy melt.

(169) Step 5: Cooling

(170) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(171) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.7% of Al, 4.20% of V, 0.7% of Si, 0.9% of Fe, 0.18% of O and the balance being Ti.

Embodiment 9

(172) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(173) Step 1: Material Pre-Treatment

(174) Aluminothermic reduction reaction materials were pre-treated separately. In particular, rutile containing a mass percentage of 92% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 650 C. for 16 hours, CaO was roasted at 200 C. for 16 hours, and KClO.sub.3 was dried at 180 C. for 24 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(175) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of rutile to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(176) Among the aluminothermic reduction reaction materials, the particle size of each of the material is as follows: rutile is no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(177) Step 2: Aluminothermic Self-Propagating Reaction

(178) The weighed aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, the material mixture was divided into 8 parts.

(179) Aluminum powder was assigned to each part of the material mixture according to the sequence of each part of the material mixture fed into a reaction furnace, wherein the amount of aluminium powder assigned is sequentially 1.20, 1.1, 1.0, 0.95, 0.925, 0.90, 0.875 and 0.85 times of the stoichiometric ratio. The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t98%.

(180) Wherein the mass of a part of the material mixture that was fed into the reaction furnace as a first batch accounts for 22.2% of the mass of the total material mixture, and the first batch of the material mixture requires an addition of magnesium powder as an ignition substance to ignite the material mixture to induce a self-propagating reaction, so that a first-batch high-temperature melt that is sufficient to initiate subsequent reactions was obtained.

(181) After that, other parts of the material mixture were sequentially fed into the reaction furnace according to a sequence with reduced stoichiometric ratio of the amount of aluminium powder assigned until all materials were fully reacted to obtain high-temperature melt.

(182) Step 3: Melt Separation Under Electromagnetic Field

(183) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1750 C. and the heat insulation time was 15 minutes in the melt separation process.

(184) Step 4: Slag Washing Refining

(185) (1) 95% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.2 and at a stirring speed of 150 rpm under a temperature of 1750 C.

(186) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.05.

(187) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 50% of CaO, 0% of Na.sub.2O, 30% of TiO.sub.2, and 15% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 180 C. for 20 hours.

(188) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1750 C. is kept, and the continuously eccentrically mechanical stirring is performed for 15 minutes, and then stopped to obtain titanium alloy melt.

(189) Step 5: Cooling

(190) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(191) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.5% of Al, 4.30% of V, 0.2% of Si, 0.6% of Fe, 0.16% of O and the balance being Ti.

Embodiment 10

(192) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(193) Step 1: Material Pre-Treatment

(194) Aluminothermic reduction reaction materials were pre-treated separately. In particular, rutile containing a mass percentage of 93% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 500 C. for 24 hours, CaO was roasted at 250 C. for 12 hours, and KClO.sub.3 was dried at 150 C. for 18 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(195) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of rutile to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(196) Among the aluminothermic reduction reaction materials, the particle size of each of the material is as follows: rutile is no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(197) Step 2: Aluminothermic Self-Propagating Reaction

(198) The aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, and the material mixture was fed into a continuous material mixer at a constant flow rate.

(199) Besides, aluminum powder were added into the continuous material mixer at a flow rate with reduced gradient so that the amount of aluminum powder assigned to the continuously fed material mixture is gradually reduced from 1.28 times of the stoichiometric ratio to 0.78 times of the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminum powder assigned conforms the following relational formula:
m=(bc)a(1).

(200) In the formula, m is the times of gradient changes of the amount of aluminium powder assigned, b is the maximum amount of aluminium powder assigned, c is the minimum amount of aluminium powder assigned, a is a coefficient for gradient changes of the amount of aluminium powder assigned, where a is equal to 0.004. Through calculation, m is 128 times, and the time interval between gradient changes of the flow of aluminum powder is the total reaction time divided by m.

(201) The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein:
m.sub.a=m.sub.t98%.

(202) The aluminothermic self-propagating reaction materials were mixed uniformly in the continuous material mixer, and were continuously fed into the reaction furnace for aluminothermic reduction reaction until all materials were fully reacted to obtain high-temperature melt.

(203) Step 3: Melt Separation Under Electromagnetic Field

(204) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, and thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1700 C. and the heat insulation time was 20 minutes in the melt separation process.

(205) Step 4: Slag Washing Refining

(206) (1) 85% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 100 rpm under a temperature of 1700 C.

(207) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.04.

(208) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 49% of CaO, 1% of Na.sub.2O, 40% of TiO.sub.2, and 5% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 150 C. for 10 hours.

(209) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1700 C. is kept, and the continuously eccentrically mechanical stirring is performed for 10 minutes, and then stopped to obtain titanium alloy melt.

(210) Step 5: Cooling

(211) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(212) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.8% of Al, 4.50% of V, 0.4% of Si, 0.7% of Fe, 0.22% of O and the balance being Ti.

Embodiment 11

(213) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(214) Step 1: Material Pre-Treatment

(215) Aluminothermic reduction reaction materials were pre-treated separately. In particular, high-titanium slags containing a mass percentage of 93% of TiO.sub.2, titanium dioxide containing a mass percentage of 99.8% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 550 C. for 36 hours, CaO was roasted at 250 C. for 12 hours, and KClO.sub.3 was dried at 150 C. for 24 hours, to obtain pre-treated aluminothermic reduction reaction materials, wherein the mixing mass ratio of high-titanium slags to titanium dioxide is 1 to 1.

(216) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of high-titanium slags and titanium dioxide to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(217) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: high-titanium slags are no larger than 3 mm, titanium dioxide is no larger than 0.02 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(218) Step 2: Aluminothermic Self-Propagating Reaction

(219) The aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, and the material mixture was fed into a continuous material mixer at a constant flow rate.

(220) Besides, aluminum powder were added into the continuous material mixer at a flow rate with reduced gradient so that the amount of aluminium powder assigned to the continuously fed material mixture is gradually reduced from 1.27 times of the stoichiometric ratio to 0.7 times of the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminium powder assigned conforms the following relational formula:
m=(bc)a(1).

(221) In the formula, m is the times of gradient changes of the amount of aluminium powder assigned, b is the maximum amount of aluminium powder assigned, c is the minimum amount of aluminium powder assigned, a is a coefficient for gradient changes of the amount of aluminium powder assigned, where a is equal to 0.002. Through calculation, m is 285 times.

(222) The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t97%.

(223) The aluminothermic self-propagating reaction materials were mixed uniformly in the continuous material mixer, and were continuously fed into the reaction furnace for aluminothermic reduction reaction until all materials were fully reacted to obtain high-temperature melt.

(224) Step 3: Melt Separation Under Electromagnetic Field

(225) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1750 C. and the heat insulation time was 15 minutes in the melt separation process.

(226) Step 4: Slag Washing Refining

(227) (1) 90% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 150 rpm under a temperature of 1750 C.

(228) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.06.

(229) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 10% of CaF.sub.2, 43% of CaO, 2% of Na.sub.2O, 35% of TiO.sub.2, and 10% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting was performed at a roasting temperature of 200 C. for 12 hours.

(230) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1750 C. is kept, and the continuously eccentrically mechanical stirring is performed for 10 minutes, and then stopped to obtain titanium alloy melt.

(231) Step 5: Cooling

(232) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(233) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.6% of Al, 4.0% of V, 0.7% of Si, 0.9% of Fe, 0.13% of O and the balance being Ti.

Embodiment 12

(234) The method for preparing titanium alloys based on aluminothermic self-propagating gradient reduction and slag-washing refining specially comprises the following steps:

(235) Step 1: Material Pre-Treatment

(236) Aluminothermic reduction reaction materials were pre-treated separately. In particular, high-titanium slags containing a mass percentage of 92% of TiO.sub.2, and V.sub.2O.sub.5 powder, were roasted separately at 700 C. for 24 hours, CaO was roasted at 250 C. for 12 hours, and KClO.sub.3 was dried at 250 C. for 24 hours, to obtain pre-treated aluminothermic reduction reaction materials.

(237) The pre-treated aluminothermic reduction reaction materials were weighed with a proportional ratio, wherein the proportional ratio is the mass ratio of high-titanium slags to aluminum powder to V.sub.2O.sub.5 powder to CaO to KClO.sub.3 being 1.0:0.26:0.045:0.16:0.28.

(238) Among the aluminothermic reduction reaction materials, the particle size of each of the materials is as follows: high-titanium slags are no larger than 3 mm, aluminum powder is no larger than 2 mm, V.sub.2O.sub.5 powder is no larger than 0.2 mm, CaO is no larger than 0.2 mm, and KClO.sub.3 is no larger than 2 mm.

(239) Step 2: Aluminothermic Self-Propagating Reaction

(240) The aluminothermic self-propagating reaction materials other than aluminum powder were mixed uniformly to obtain a material mixture, and the material mixture was fed into a continuous material mixer at a constant flow rate.

(241) Besides, aluminum powder were added into the continuous material mixer at a flow rate with reduced gradient so that the amount of aluminium powder assigned to the continuously fed material mixture is gradually reduced from 1.23 times of the stoichiometric ratio to 0.72 times of the stoichiometric ratio, wherein the times of gradient changes of the amount of aluminium powder assigned conforms the following relational formula:
m=(bc)(1).

(242) In the formula, m is the times of gradient changes of the amount of aluminium powder assigned, b is the maximum amount of aluminium powder assigned, c is the minimum amount of aluminium powder assigned, a is a coefficient for gradient changes of the amount of aluminium powder assigned, where a is equal to 0.001. Through calculation, m is 450 times.

(243) The total mass of the amount of aluminum powder added obtained from a chemical reaction equation is a theoretical total mass m.sub.t, and the actual total mass of the addition of aluminum powder is m.sub.a, wherein
m.sub.a=m.sub.t95%.

(244) The aluminothermic self-propagating reaction materials were mixed uniformly in the continuous material mixer, and were continuously fed into the reaction furnace for aluminothermic reduction reaction until all materials were fully reacted to obtain high-temperature melt.

(245) Step 3: Melt Separation Under Electromagnetic Field

(246) The high-temperature melt was heated through electromagnetic induction to perform heat insulation and melt separation, and thereby slag-metal separation was realized and a layered melt with an upper layer being aluminum oxide based melt slags and a lower layer being alloy melt was obtained, wherein the temperature was controlled at 1750 C. and the heat insulation time was 15 minutes in the melt separation process.

(247) Step 4: Slag Washing Refining

(248) (1) 90% of the total volume of the aluminum oxide based melt slags at the upper layer was removed, the remaining aluminum oxide based melt slags and the alloy melt at the lower layer were stirred by an eccentrically mechanical stirring with an eccentricity of 0.4 and at a stirring speed of 50 rpm under a temperature of 1750 C.

(249) (2) After the melt was uniformly mixed, the stirring was continuously performed, and CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown into the uniformly-mixed melt from the bottom of a medium-frequency induction furnace by taking high-purity inert gas as carrier gas, wherein the mass ratio of the aluminothermic self-propagating reaction materials to the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags is 1.0:0.07.

(250) The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags contain the following chemical ingredients and mass percentages: 5% of CaF.sub.2, 49% of CaO, 1% of Na.sub.2O, 30% of TiO.sub.2, and 15% of V.sub.2O.sub.5, wherein each component of CaO, CaF.sub.2, Na.sub.2O, TiO.sub.2 and V.sub.2O.sub.5 powder contained in the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags has a particle size no larger than 0.2 mm. The CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were pre-treated before being used. Roasting is performed at a roasting temperature of 200 C. for 24 hours.

(251) (3) After the CaF.sub.2CaOTiO.sub.2V.sub.2O.sub.5 based refining slags were sprayed and blown, the heat insulation at 1750 C. is kept, and the continuously eccentrically mechanical stirring is performed for 10 minutes, and then stopped to obtain titanium alloy melt.

(252) Step 5: Cooling

(253) The titanium alloy melt was cooled to room temperature, and the melting slags on the top were removed to obtain titanium alloys.

(254) The titanium alloys prepared by the present invention contain the following chemical ingredients and mass percentages: 5.5% of Al, 3.60% of V, 0.4% of Si, 0.9% of Fe, 0.10% of O and the balance being Ti.