RESOURCE COMPREHENSIVE UTILIZATION PROCESS OF RED MUD, FLY ASH, STEEL SLAG AND COAL GANGUE SOLID WASTES

Abstract

The present disclosure belongs to the technical field of industrial waste solid recycling, and particularly relates to a resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes. By using the resource comprehensive utilization process, Na.sub.2CO.sub.3, O.sub.2 and a reducing agent are added into industrial waste solids for reaction and then molten iron and liquid slag water are separated; a sodium salt is added into the liquid slag water for reaction to obtain a reaction solution and sediment; the reaction solution is successively introduced into a calcium salt precipitation tank, an aluminum salt precipitation tank and a silicic acid tank and then CO.sub.2 is introduced into the above tanks for acidification reaction, respectively, and a calcium salt, an aluminum salt, a silicic acid and an alkaline solution are obtained after filtration in sequence.

Claims

1. A resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes, comprising the following steps: (1) heating industrial solid wastes to 1800-2400 C., then adding Na.sub.2CO.sub.3, O.sub.2 and a reducing agent for reaction, so as to separate molten iron and liquid slag water; (2) cooling the liquid slag water separated from step (1) to 30-100 C. and then feeding the cooled liquid slag water into a reactor, adding a sodium salt, and reacting at 30-300 C. to obtain a reaction solution and sediment; and successively introducing the reaction solution into a calcium salt precipitation tank, an aluminum salt precipitation tank and a silicic acid tank, introducing CO.sub.2 into the above tanks for acidification reaction, respectively, and then filtering to obtain a calcium salt, an aluminum salt, a silicic acid and an alkaline solution in sequence; (3) concentrating and crystallizing the alkaline solution filtered in step (2), crystallizing separately to obtain a potassium salt and a sodium salt by utilizing a different saturation solubility; (4) drying the sediment obtained in step (2), heating the dried sediment to 600-1300 C., introducing Cl.sub.2 for reaction to obtain gaseous TiCl.sub.4 and residue, cooling the gaseous TiCl.sub.4 to 120 C. or below for being condensed and collected, to obtain liquid TiCl.sub.4; and residue (5) cyclically washing the residue obtained in step (4) with water, then performing settling separation to obtain de-magnesium residue and a magnesium chloride solution, introducing the magnesium chloride solution into a magnesium hydroxide precipitation tank, and then adding sodium hydroxide into the tank for reaction to obtain a magnesium hydroxide precipitate.

2. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (1), the solid waste is one or more of red mud, fly ash, steel slag and coal gangue.

3. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 2, wherein the red mud is Bayer red mud.

4. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (1), the addition amount of Na.sub.2CO.sub.3 is 20-80% of the mass of industrial solid wastes.

5. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (1), the addition amount of O.sub.2 is 3-20% of the mass of industrial solid wastes.

6. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (1), the reducing agent is one or more of C, CO and H.sub.2, and the addition amount of the reducing agent is 5-30% of the mass of the industrial solid waste.

7. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (2), the sodium salt is preferably sodium nitrate; and the addition amount of the sodium salt is 10-40% of the mass of the slag water.

8. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (2), the temperatures of all the acidification reactions are 10-50 C.

9. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (4), the addition amount of Cl.sub.2 is 50-200% of the dry mass of the sediment.

10. The resource comprehensive utilization process of red mud, fly ash, steel slag and coal gangue solid wastes according to claim 1, wherein in step (5), sodium chloride is produced from an upper-layer liquid through evaporation and concentration equipment after the precipitation is completed in the magnesium hydroxide precipitation tank.

Description

DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED EMBODIMENTS

[0038] Next, the present disclosure will be further described in combination with embodiments.

[0039] Raw materials used in embodiments, unless otherwise specified, are commercially available conventional products; and process methods used in embodiments, unless otherwise specified, are all conventional methods in the art.

[0040] The red mud used in the examples is Bayer red mud, which comprises the following main chemical components in percentage by mass: 18.4% of Al.sub.2O.sub.3, 38.2% of SiO.sub.2, 21.8% of Fe.sub.2O.sub.3, 2.4% of CaO, 9.5% of Na.sub.2O, 0.8% of K.sub.2O, 3.1% of MgO, 5.5% of TiO.sub.2 and 0.3% of other components.

[0041] The fly ash used in the examples comprises the following main chemical components in percentage by mass: 33.6% of Al.sub.2O.sub.3, 35.8% of SiO.sub.2, 15.7% of Fe.sub.2O.sub.3, 5.3% of CaO, 2.2% of Na.sub.2O, 0.3% of K.sub.2O, 2.8% of MgO, 3.5% of TiO.sub.2 and 0.5% of other components.

[0042] The steel slag used in the examples comprises the following main chemical components in percentage by mass: 18.3% of Al.sub.2O.sub.3, 23.1% of SiO.sub.2, 0.5% of Fe.sub.2O.sub.3, 32.4% of CaO, 2.5% of Na.sub.2O, 0.3% of S, 12.4% of MgO, 10.1% of TiO.sub.2 and 0.4% of other components.

[0043] The coal gangue used in the examples comprises the following main chemical components in percentage by mass: 23.6% of C, 20.3% of A.sub.2O.sub.3, 40.8% of SiO.sub.2, 8.9% of Fe.sub.2O.sub.3, 1.2% of CaO, 1.8% of Na.sub.2O, 0.4% of S, 1.0% of MgO, 1.2% of TiO.sub.2 and 0.8% of other components.

EXAMPLE 1

[0044] Industrial solid waste red mud is treated by using a resource comprehensive utilization method of the present disclosure. The treatment steps are as follows:

[0045] (1) Industrial solid wastes were heated to 2400 C. by using a hydrogen furnace, then Na2CO3, O2 and C which respectively accounted for 32.4%, 12.5% and 14.8% of the mass of the industrial solid wastes were added and reacted for 180 min, followed by separating to obtain molten iron and liquid slag water.

[0046] (2) The liquid slag water separated in step (1) was cooled to 80 C. and then fed into a reactor, sodium nitrate accounting for 24.6% of the mass of the slag water was added, and then the above materials reacted for 24 h at 200 C. to obtain a reaction solution and sediment; the reaction solution was successively introduced into a calcium salt precipitation tank, an aluminum salt precipitation tank and a silicic acid tank, CO.sub.2 was introduced into the above tanks for acidifying reactions, respectively, the temperatures of all the acidifying reactions were set as 30 C., a CO.sub.2 introduction amount and reaction time were adjusted according to the extent of the reaction in the tanks, a detection instrument and a control instrument were installed in the calcium salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of calcium ions, the introduction of CO.sub.2 was ended when the content of calcium ions was detected as 0, and the aluminum salt was precisely separated to ensure the purity of the product without the doping of silicon and aluminum; the detection instrument and the control instrument were installed in the aluminum salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of aluminum ions, the introduction of CO.sub.2 was ended when the content of aluminum ions was detected as 0, and the aluminum salt was precisely separated to ensure the purity of the product without the doping of silicon; the detection instrument and the control instrument were installed in the silicic acid tank, the acidity value was detected, the introduction of CO.sub.2 was ended when the acidity value started to increase, and silicic acid was precisely separated; after the acidifying reaction in each tank was completed, a calcium salt, an aluminum salt, silicic acid and an alkaline solution were successively obtained after filtering, the obtained calcium salt, aluminum salt and silicic acid were separately dried to be directly used as products, or further treated by a known method to obtain calcium powders, aluminum oxide and silicon dioxide.

[0047] (3) The alkaline solution obtained by filtering in step (2) was concentrated and crystallized, and crystallization was performed by utilizing a different saturation solubility to obtain a potassium salt and a sodium salt.

[0048] (4) The sediment obtained in step (2) was dried and heated to 800 C., and then Cl.sub.2 accounting for 100% of the mass of the sediment was introduced for reaction so as to obtain gaseous TiCl.sub.4 and residue, and the gaseous TiCl.sub.4 was cooled to 120 C. or below for being condensed, collected, rectified and purified to obtain a high-purity TiCl.sub.4 liquid which was directly used as a product, or further treated by a known method to obtain titanium dioxide.

[0049] (5) The residue obtained in step (4) was cyclically washed with water, and then subjected to settling separation to obtain de-magnesium residue and a magnesium chloride solution, the magnesium chloride solution was filtered and then introduced into a magnesium hydroxide precipitation tank, and then sodium hydroxide was added into the above tank for reaction to obtain a magnesium hydroxide precipitate, sodium chloride was produced from an upper-layer liquid through evaporation and concentration equipment, the magnesium hydroxide precipitate was dried to obtain magnesium oxide, and the de-magnesium residue was a heavy metal-rich rare earth raw material.

EXAMPLE 2

[0050] The resource comprehensive utilization process of the present disclosure was used to treat industrial solid wastes (red mud, fly ash, steel slag and coal gangue in a mass ratio of 5:1:1:1). The treatment steps are as follows:

[0051] (1) Industrial solid wastes were heated to 1800 C. by using a hydrogen furnace, and then

[0052] Na.sub.2CO.sub.3, O.sub.2 and CO which respectively accounted for 78.9%, 19.6% and 29.5% of the mass of the industrial solid wastes were added and reacted for 200 min, followed by separating to obtain molten iron and liquid slag water.

[0053] (2) The liquid slag water separated in step (1) was cooled to 30 C. and then fed into a reactor, sodium nitrate accounting for 40% of the mass of the slag water was added, and then the above materials reacted for 24 h at 100 C. to obtain a reaction solution and sediment; the reaction solution was successively introduced into a calcium salt precipitation tank, an aluminum salt precipitation tank and a silicic acid tank, CO.sub.2 was introduced into the above tanks for acidifying reactions respectively, the temperatures of all the acidifying reactions were set as 10 C., a CO.sub.2 introduction amount and reaction time were adjusted according to the extent of the reaction in the tanks, a detection instrument and a control instrument were installed in the calcium salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of calcium ions, the introduction of CO.sub.2 was ended when the content of calcium ions was detected as 0, and the calcium salt was precisely separated to ensure the purity of the product without the doping of silicon and aluminum; the detection instrument and the control instrument were installed in the aluminum salt precipitation tank, the CO.sub.2 introduction amount and acidity value were detected by detecting the numerical value of aluminum ions, the introduction of CO.sub.2 was ended when the content of aluminum ions was detected as 0, and the aluminum salt was precisely separated to ensure the purity of the product without the doping of silicon; a detection instrument and a control instrument were installed in the silicic acid tank, the acidity value was detected, the introduction of CO.sub.2 was ended when the acidity value started to increase, and silicic acid was precisely separated; after the acidifying reaction in each tank was completed, a calcium salt, an aluminum salt, silicic acid and an alkaline solution were obtained after filtering, and the obtained calcium salt, aluminum salt and silicic acid were separately dried to be directly used as products, or further treated by a known method to obtain calcium powders, aluminum oxide and silicon dioxide.

[0054] (3) The alkaline solution obtained by filtering in step (2) was concentrated and crystallized, and crystallization was performed by utilizing a different saturation solubility to obtain a potassium salt and a sodium salt.

[0055] (4) The sediment obtained in step (2) was dried and heated to 600 C., and then Cl.sub.2 accounting for 200% of the mass of the sediment was introduced for reaction so as to obtain gaseous TiCl.sub.4 and residue, and the gaseous TiCl.sub.4 was cooled to 120 w or below for being, condensed, collected, rectified and purified to obtain a high-purity TiCl.sub.4 liquid which was directly used as a product, or further treated by a known method to obtain titanium dioxide.

[0056] (5) The residue obtained in step (4) was cyclically washed with water, and then subjected to settling separation to obtain de-magnesium residue and a magnesium chloride solution, the magnesium chloride solution was filtered and then introduced into a magnesium hydroxide precipitation tank, and then sodium hydroxide was added into the above tank for reaction to obtain a magnesium hydroxide precipitate, sodium chloride was produced from an upper-layer liquid through evaporation and concentration equipment, the magnesium hydroxide precipitate was dried to obtain magnesium oxide, and the de-magnesium residue was a heavy metal-rich rare earth raw material.

EXAMPLE 3

[0057] The resource comprehensive utilization process of the present disclosure was used to treat industrial solid wastes (red mud and fly ash in a mass ratio of 1:1). The treatment steps are as follows:

[0058] (1) Industrial solid wastes were heated to 2000 C. by using a hydrogen furnace, then Na.sub.2CO.sub.3, O.sub.2 and H.sub.2 which respectively accounted for 20.2%, 3.2% and 5.4% of the mass of the industrial solid wastes were added and reacted for 60 min, followed by separating to obtain molten iron and liquid slag water.

[0059] (2) The liquid slag separated in step (1) was cooled to 100 C. and then fed into a reactor, sodium nitrate accounting for 10.2% of the mass of the slag water was added, and then the above materials reacted for 72 h at 300 C. to obtain a reaction solution and sediment; the reaction solution was successively introduced into a calcium salt precipitation tank, an aluminum salt precipitation tank and a silicic acid tank, CO.sub.2 was introduced into the above tanks for acidifying reactions, respectively, the temperatures of all the acidifying reactions were set as 50 C., a CO.sub.2 introduction amount and reaction time were adjusted according to the extent of the reaction in the tanks, a detection instrument and a control instrument were installed in the calcium salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of calcium ions, the introduction of CO.sub.2 was ended when the content of calcium ions was detected as 0, the calcium salt was precisely separated to ensure the purity of the product without the doping of silicon and aluminum; a detection instrument and a control instrument were installed in the aluminum salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of aluminum ions, the introduction of CO.sub.2 was ended when the content of aluminum ions was detected as 0, and the aluminum salt was precisely separated to ensure the purity of the product without the doping of silicon; the detection instrument and the control instrument were installed in the silicic acid tank, the acidity value was detected, the introduction of CO.sub.2 was ended when the acidity value started to increase, and silicic acid was precisely separated; after the acidifying reaction in each tank was completed, a calcium salt, an aluminum salt, silicic acid and an alkaline solution were successively obtained after filtering, the obtained calcium salt, aluminum salt and silicic acid were separately dried to be directly used as products, or further treated by a known method to obtain calcium powders, aluminum oxide and silicon dioxide.

[0060] (3) The alkaline solution obtained by filtering in step (2) was concentrated and crystallized, and crystallization was performed by utilizing a different saturation solubility to obtain a potassium salt and a sodium salt.

[0061] (4) The sediment obtained in step (2) was dried and heated to 1300 C., and then Cl.sub.2 accounting for 50% of the mass of the sediment was introduced for reaction so as to obtain gaseous TiCl.sub.4 and residue, and the gaseous TiCl.sub.4 was cooled to 120 C. or below for being, condensed, collected, rectified and purified to obtain a high-purity TiCl.sub.4 liquid which was directly used as a product, or further treated by a known method to obtain titanium dioxide.

[0062] (5) The residue obtained in step (4) was cyclically washed with water, and then subjected to settling separation to obtain de-magnesium residue and a magnesium chloride solution, the magnesium chloride solution was filtered and then introduced into a magnesium hydroxide precipitation tank, and then sodium hydroxide was added into the above tank for reaction to obtain a magnesium hydroxide precipitate, sodium chloride was produced from an upper-layer liquid through evaporation and concentration equipment, the magnesium hydroxide precipitate was dried to obtain magnesium oxide, and the de-magnesium residue was a heavy metal-rich rare earth raw material.

EXAMPLE 4

[0063] The resource comprehensive utilization process of the present disclosure was used to treat industrial solid wastes (red mud and coal gangue in a mass ratio of 3:2). The treatment steps are as follows:

[0064] (1) Industrial solid wastes were heated to 2200 C. by using a hydrogen furnace, then Na.sub.2CO.sub.3, O.sub.2 and C which respectively accounted for 54.8%, 15.4% and 10.5% of the mass of the industrial solid wastes were added and reacted for 120 min, followed by separating to obtain molten iron and liquid slag water.

[0065] (2) The liquid slag separated in step (1) was cooled to 50 C. and then fed into a reactor, sodium nitrate accounting for 32.8% of the mass of the slag water was added, and then the above materials reacted for 36 h at 200 C. to obtain a reaction solution and sediment; the reaction solution was successively introduced into a calcium salt precipitation tank, an aluminum salt precipitation tank and a silicic acid tank, CO.sub.2 was introduced into the above tanks for acidifying reactions, respectively, the temperatures of all the acidifying reactions were set as 25 C., a CO.sub.2 introduction amount and reaction time were adjusted according to the extent of the reaction in the tanks, a detection instrument and a control instrument were installed in the calcium salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of calcium ions, the introduction of CO.sub.2 was ended when the content of calcium ions was detected as 0, and the calcium salt was precisely separated to ensure the purity of the product without the doping of silicon and aluminum; the detection instrument and the control instrument were installed in the aluminum salt precipitation tank, the CO.sub.2 introduction amount and acidity value were controlled by detecting the numerical value of the aluminum ions, the introduction of CO.sub.2 was ended when the content of the aluminum ions was detected as 0, the aluminum salt was precisely separated to ensure the purity of the product without the doping of silicon; the detection instrument and the control instrument were installed in the silicic acid tank, the acidity value was detected, the introduction of CO.sub.2 was ended when the acidity value started to increase, and silicic acid was precisely separated; after the acidifying reaction in each tank was completed, a calcium salt, an aluminum salt, silicic acid and an alkaline solution were obtained after filtering, and the obtained calcium salt, aluminum salt and silicic acid were separately dried to be directly used as products, or further treated by a known method to obtain calcium powders, aluminum oxide and silicon dioxide.

[0066] (3) The alkaline solution obtained by filtering in step (2) was concentrated and crystallized, and and crystallization was performed by utilizing a different saturation solubility to obtain a potassium salt and a sodium salt.

[0067] (4) The sediment obtained in step (2) was dried and heated to 1000 C., and then Cl.sub.2 accounting for 150% of the mass of the sediment was introduced for reaction so as to obtain gaseous TiCl.sub.4 and residue, and the gaseous TiCl.sub.4 was cooled to 120 C. or below for being, condensed, collected, rectified and purified to obtain a high-purity TiCl.sub.4 liquid which was directly used as a product, or further treated by a known method to obtain titanium dioxide.

[0068] (5) The residue obtained in step (4) was cyclically washed with water, and then subjected to settling separation to obtain de-magnesium residue and a magnesium chloride solution, the magnesium chloride solution was filtered and then introduced into a magnesium hydroxide precipitation tank, and then sodium hydroxide was added into the above tank for reaction to obtain a magnesium hydroxide precipitate, sodium chloride was produced from an upper-layer liquid through evaporation and concentration equipment, the magnesium hydroxide precipitate was dried to obtain magnesium oxide, and the de-magnesium residue was a heavy metal-rich rare earth raw material.