Method for preparing vanadium and vanadium alloy powder from vanadium-containing materials through shortened process

Abstract

Disclosed is a method for preparing vanadium or vanadium alloy powder from a vanadium-containing raw material through a shortened process, including: calcinating a mixture of a vanadium-containing raw material and an alkali compound for oxidation to form a water-soluble vanadate; purifying the vanadate followed by vanadium precipitation to produce an intermediate CaV.sub.2O.sub.6 with high purity; dissolving CaV.sub.2O.sub.6 in a molten-salt medium together with other raw materials to form a uniform reaction system; and introducing a reducing agent to the system followed by separation, washing and drying to produce vanadium or vanadium alloy powder having a particle size of 50-800 nm and a purity of 99.0 wt % or more. The method can continuously process vanadium-containing raw materials to prepare vanadium or vanadium alloy powder.

Claims

1. A method for preparing vanadium powder or vanadium alloy powder from a vanadium-containing raw material, comprising: (1) mixing the vanadium-containing raw material with an alkali compound to produce a first mixture, and then calcinating the first mixture for oxidation to produce a calcinated product; (2) pulverizing the calcinated product obtained in step (1) to produce vanadium-containing particles and then dissolving the vanadium-containing particles followed by solid-liquid separation to produce a vanadium-containing solution; purifying the vanadium-containing solution followed by adding with a calcium salt for vanadium precipitation to obtain an intermediate CaV.sub.2O.sub.6; (3) mixing the intermediate CaV.sub.2O.sub.6 obtained in step (2) with a molten-salt medium to produce a second mixture, and dehydrating the second mixture under vacuum followed by heating for melting to form a molten-salt reaction system; (4) adding a reducing agent to the molten-salt reaction system obtained in step (3) for thermal reduction reaction to produce a thermal-reduced product; and (5) subjecting the thermal-reduced product obtained in step (4) to solid-liquid separation, washing and drying to obtain a target product; wherein in step (3), sodium metaaluminate is added during the mixing of the intermediate CaV.sub.2O.sub.6 with the molten-salt medium.

2. The method of claim 1, wherein in step (1), the alkali compound is at least one compound selected from the group consisting of Na.sub.2O, K.sub.2O, NaOH, KOH, Na.sub.2CO.sub.3 and K.sub.2CO.sub.3.

3. The method of claim 2, wherein the alkali compound is Na.sub.2CO.sub.3 and/or K.sub.2CO.sub.3.

4. The method of claim 1, wherein in step (1), in the first mixture of the vanadium-containing raw material and the alkali compound, the vanadium-containing raw material has a molar percentage content of 5-25% and the alkali compound has a molar percentage content of 75-95%.

5. The method of claim 1, wherein in step (1), a calcination temperature is 700-900° C. and a calcination time is 3-10 h.

6. The method of claim 1, wherein in step (2), the vanadium-containing particles have a particle size of 150-300 mesh.

7. The method of claim 1, wherein in step (2), the calcium salt is CaO and/or CaCl.sub.2.

8. The method of claim 1, wherein in step (3), the molten-salt medium consists of compound A and compound B; wherein the compound A is at least one compound selected from the group consisting of CaCl.sub.2, NaF and KF; and the compound B is at least one compound selected from the group consisting of NaCl, KCl, LiCl, NaAlO.sub.2, CaTiO.sub.3, Na.sub.2TiO.sub.3, K.sub.2TiO.sub.3 and TiO.sub.2.

9. The method of claim 8, wherein in the molten-salt medium, the compound A has a molar percentage content of 40-100% and the compound B has a molar percentage content of 0-60%.

10. The method of claim 1, wherein in step (3), in the second mixture of CaV.sub.2O.sub.6 and the molten-salt medium, CaV.sub.2O.sub.6 has a molar percentage content of 2-12%, and the molten-salt medium has a molar percentage content of 88-98%.

11. The method of claim 1, wherein in step (3), a vacuum degree is 0.1-0.3 MPa, and a vacuum dehydration temperature is 150-450° C.

12. The method of claim 1, wherein in step (3), a temperature of the molten-salt reaction system is 500-950° C.

13. The method of claim 1, wherein in step (4), the reducing agent comprises at least one of sodium, calcium and magnesium.

14. The method of claim 1, wherein in step (4), a thermal reduction reaction temperature is 400-800° C.

15. The method of claim 1, wherein in step (4), the thermal reduction reaction is carried out under a protective atmosphere.

16. The method of claim 1, wherein in step (5), the solid-liquid separation is performed by vacuum filtration.

17. The method of claim 1, wherein in step (5), the washing is performed sequentially with an acid and water.

18. The method of claim 1, wherein in step (5), the drying is performed at a vacuum degree of 0.1-0.5 MPa and a temperature of 30-50° C.

19. A method for preparing vanadium powder or vanadium alloy powder from a vanadium-containing raw material, comprising: (1) mixing the vanadium-containing raw material with an alkali compound to produce a first mixture, and then calcinating the first mixture at 700-900° C. for 3-10 h for oxidation to produce a calcinated product; wherein in the first mixture of the vanadium-containing raw material and the alkali compound, the vanadium-containing raw material has a molar percentage content of 5-25% and the alkali compound has a molar percentage content of 75-95%; and the alkali compound is at least one compound selected from the group consisting of Na.sub.2O, K.sub.2O, NaOH, KOH, Na.sub.2CO.sub.3 and K.sub.2CO.sub.3; (2) pulverizing the calcinated product obtained in step (1) to produce a vanadium-containing particles of 150-300 mesh and then dissolving the vanadium-containing particles followed by solid-liquid separation to produce a vanadium-containing solution; purifying the vanadium-containing solution followed by adding with CaO and/or CaCl.sub.2 for vanadium precipitation to obtain an intermediate CaV.sub.2O.sub.6; (3) mixing the intermediate CaV.sub.2O.sub.6 obtained in step (2) with a molten-salt medium to produce a second mixture, and dehydrating the second mixture at a vacuum degree of 0.1-0.3 MPa and a temperature of 150-450° C. followed by heating to 500-950° C. for melting to form a molten-salt reaction system; wherein the molten-salt medium consists of 40-100% by molar percentage content of compound A and 0-60% by molar percentage content of compound B; and the compound A is at least one compound selected from the group consisting of CaCl.sub.2, NaF and KF, and the compound B is at least one compound selected from the group consisting of NaCl, KCl, LiCl, NaAlO.sub.2, CaTiO.sub.3, Na.sub.2TiO.sub.3, K.sub.2TiO.sub.3 and TiO.sub.2; in the second mixture of CaV.sub.2O.sub.6 and the molten-salt medium, CaV.sub.2O.sub.6 has a molar percentage content of 2-12% and the molten-salt medium has a molar percentage content of 88-98%; and sodium metaaluminate is introduced during the mixing of the intermediate CaV.sub.2O.sub.6 with the molten-salt medium; (4) adding a reducing agent to the molten-salt reaction system obtained in step (3) to carry out a thermal reduction reaction at 400-800° C. under an argon atmosphere to produce a thermal-reduced product; wherein the reducing agent comprises at least one of sodium, calcium and magnesium; and (5) subjecting the thermal-reduced product obtained in step (4) to vacuum filtration followed by washing sequentially with an acid and water and drying at a vacuum degree of 0.1-0.5 MPa and a temperature of 30-50° C. to obtain a target product.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a graph showing XRD phase analysis of the V nanopowder prepared in Example 1 of the disclosure.

(2) FIG. 2 is a FESEM image of the V nanopowder prepared in Example 1 of the disclosure.

(3) FIG. 3 is a graph showing XRD phase analysis of the V—Al alloy nanopowder prepared in Example 2 of the disclosure.

(4) FIG. 4 is a FESEM image of the V—Al alloy nanopowder prepared in Example 2 of the disclosure.

(5) The disclosure will be further described in detail below with reference to the embodiments. However, the following embodiments are merely illustrative of the disclosure and are not intended to limit the scope of the disclosure. The scope of the disclosure is defined by the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS

(6) The technical solutions of the disclosure will be further described below with reference to the accompanying drawings and embodiments.

EXAMPLE 1

(7) This example provided a method for preparing vanadium powder from a vanadium-containing raw material through a shortened process, which was carried out according to the following steps.

(8) (1) 200 g of vanadium slag and 24 g of Na.sub.2CO.sub.3 were uniformly mixed, pressed into a block, and calcinated in a furnace at 800° C. for 6 h for oxidation.

(9) (2) The calcinated product obtained in step (1) was cooled to room temperature and pulverized into particles having a particle size of 200 mesh. The particles were sequentially washed with water, dissolved, filtered, purified and added with CaCl.sub.2 for vanadium precipitation to obtain an intermediate CaV.sub.2O.sub.6.

(10) (3) The intermediate CaV.sub.2O.sub.6 obtained in step (2) was mixed with a NaCl—CaCl.sub.2 molten-salt medium in a molar ratio of 3:97 and melted in a reaction furnace at 650° C. to form a molten-salt reaction system, where the molar contents of NaCl and CaCl.sub.2 in the molten-salt medium were 48% and 52%, respectively.

(11) (4) The molten-salt reaction system obtained in step (3) was added with metal calcium as a reducing agent and reacted at 600° C. under the protection of argon for 6 h for thermal reduction, where a flow rate of the argon was 30 mL/s. After the reaction was completed, the reaction mixture was cooled to room temperature.

(12) (5) The thermal-reduced product obtained in step (4) was filtered under vacuum to separate a target product from the molten-salt medium. Then the target product was washed sequentially with a diluted hydrochloric acid having a concentration of 3-5 wt % and distilled water, and dried at a vacuum degree of 0.3 MPa and a temperature of 40° C. to obtain the target product (V powder).

(13) The prepared target product was characterized by XRD phase analysis and FESEM surface morphology. As shown in FIG. 1, the XRD phase analysis showed that the product obtained in this example was an elemental metal V; and as shown in FIG. 2, the obtained V nanopowder was spherically-agglomerated particles having a particle size of 50-250 nm. The test results showed that the V powder had a purity of 99.15 wt %.

EXAMPLE 2

(14) This example provided a method for preparing a vanadium alloy powder from a vanadium-containing raw material through a shortened process, which was carried out according to the following steps.

(15) (1) 200 g of vanadium slag and 35 g of K.sub.2CO.sub.3 were uniformly mixed, pressed into a block, and calcinated at 850° C. in a furnace for 8 h for oxidation.

(16) (2) The calcinated product obtained in step (1) was cooled to room temperature and pulverized into particles having a particle size of 200 mesh. The particles were sequentially washed with water, dissolved, filtered, purified and added with CaO for vanadium precipitation to obtain an intermediate CaV.sub.2O.sub.6.

(17) (3) The intermediate CaV.sub.2O.sub.6 obtained in step (2) was mixed with sodium metaaluminate and a KCl—NaCl—CaCl.sub.2 molten-salt medium in a molar ratio of 2.5:8:89.5, and melted at 750° C. in a reaction furnace to form a molten-salt reaction system, where the molar contents of KCl, NaCl and CaCl.sub.2 in the molten-salt medium were 20%, 20% and 60%, respectively.

(18) (4) The molten-salt reaction system obtained in step (3) was added with metal sodium as a reducing agent and reacted at 650° C. under the protection of argon for 8 h for thermal reduction reaction, where a flow rate of argon was 35 mL/s. After the reaction was completed, the reaction mixture was cooled to room temperature.

(19) (5) The thermal-reduced product obtained in step (4) was filtered under vacuum to separate a target product from the molten-salt medium. Then the target product was washed sequentially with a diluted hydrochloric acid having a concentration of 3-5 wt % and distilled water, and dried at a vacuum degree of 0.2 MPa and a temperature of 45° C. to obtain the target product (V—Al alloy powder).

(20) The prepared target product was characterized by XRD phase analysis and FESEM surface morphology. As shown in FIG. 3, the XRD phase analysis showed that the product obtained in this example was a V—Al alloy; and as shown in FIG. 4, the obtained V—Al alloy nanopowder was spherically-agglomerated particles having a particle size of 100-300 nm. The test results showed that the obtained V—Al alloy powder had a purity of 99.15 wt %.

EXAMPLE 3

(21) This example provided a method for preparing vanadium powder from a vanadium-containing raw material through a shortened process, which was carried out according to the following steps.

(22) (1) 200 g of vanadium slag and 30 g of K.sub.2CO.sub.3 were uniformly mixed, pressed into a block, and calcinated at 900° C. in a furnace for 3.5 h for oxidation.

(23) (2) The calcinated product obtained in step (1) was cooled to room temperature and pulverized into particles having a particle size of 150 mesh. The obtained particles were sequentially washed with water, dissolved, filtered, purified and added with CaCl.sub.2 for vanadium precipitation to obtain an intermediate CaV.sub.2O.sub.6.

(24) (3) The intermediate CaV.sub.2O.sub.6 obtained in step (2) was mixed with a CaCl.sub.2 molten-salt medium in a molar ratio of 10:90 and melted at 800° C. in a reaction furnace to form a molten-salt reaction system, where the molar content of CaCl.sub.2 in the molten-salt medium was 100%.

(25) (4) The molten-salt reaction system obtained in step (3) was added with metal magnesium as a reducing agent and reacted at 650° C. under the protection of argon for 5 h for thermal reduction reaction, where a flow rate of the argon was 30 mL/s.

(26) (5) The thermal-reduced product obtained in step (4) was filtered under vacuum to separate a target product from the molten-salt medium. Then the target product was washed sequentially with a diluted hydrochloric acid having a concentration of 3-5 wt % and distilled water, and dried at a vacuum degree of 0.4 MPa and a temperature of 35° C. to obtain the target product (V powder).

(27) The test results showed that the obtained V powder had a purity of 99.20 wt %.

(28) Described above are preferred embodiments of the disclosure, which are not intended to limit the disclosure. Various simple modifications can be made to the technical solutions of the disclosure within the scope of the disclosure, which should fall within the scope of the disclosure.

(29) It should be further noted that in the case of no contradiction, the specific technical features described in the above specific embodiments may be combined in any suitable manner. Therefore, the various possible combinations will not be described separately in the disclosure.

(30) In addition, any combination of various embodiments of the disclosure made without departing from the spirit of the disclosure should fall within the scope of the disclosure.