Method of producing titanium and titanium alloy nanopowder from titanium-containing slag through shortened process

Abstract

Disclosed is a method of producing titanium and titanium alloy nanopowder from titanium-containing slag through a shortened process. The method includes: (1) subjecting titanium-containing slag to high-temperature oxidation and enrichment and then melting to precipitate titanium-enriched slag; (2) subjecting the titanium-enriched slag to pulverization and gravity flotation; (3) carrying out secondary enrichment; (4) preparing a molten salt reaction system; (5) synthesizing titanium and salt-containing titanium alloy nanopowder by reduction reaction; and (6) vacuum filtering, pickling, washing and vacuum drying the salt-containing titanium alloy nanopowder; and then separating titanium alloy nanopowder from the molten salt. Using the present method, the titanium-containing slag can be continuously treated to produce titanium and titanium alloy nanopowder. It requires a shortened process, a simple equipment and low energy consumption. The process is environmentally friendly and produces excellent products without solids, gas or liquids that are harmful to environment.

What is claimed is: 
     
         1 . A method of producing titanium and titanium alloy nanopowder from titanium-containing slag through a shortened process, comprising:
 1) mixing titanium-containing slag A with a modifier B in a reaction vessel; heating the reaction vessel to a reaction temperature for oxidation and enrichment, titanium in the titanium-containing slag A being formed into TiO 3   2−  by the modifier B; and then cooling to precipitate titanium-enriched slag containing titanate C;   2) subjecting the titanium-enriched slag obtained in step 1) to pulverization, gravity flotation and drying to separate the titanium-enriched slag from other impure ores;   3) repeating steps 1) and 2) to improve purity of the titanate C as an intermediate;   4) mixing the titanate C obtained in step 3) and a molten salt medium; dehydrating under vacuum and then melting at 550-900° C. to form a molten salt reaction system, titanium in the mixture being formed into TiO 3   2− ;   5) adding a reducing agent into the molten salt reaction system obtained in step 4) for thermal reduction in an inert gas at 400-900° C. to synthesize titanium and salt-containing titanium alloy nanopowder; and   6) vacuum filtering, pickling, washing and vacuum drying the salt-containing titanium alloy nanopowder obtained in step 5); and then separating the titanium alloy nanopowder from the salt-containing titanium alloy nanopowder to obtain titanium and titanium alloy nanopowder.   
     
     
         2 . The method of  claim 1 , wherein in step 1) the modifier B is selected from one or more of Na 2 O, CaO, K 2 O, NaOH, Ca(OH) 2 , KOH, Na 2 CO 3 , Ca 2 CO 3  and K 2 CO 3 . 
     
     
         3 . The method of  claim 1 , wherein in step 1) the titanate C is selected from one or more of Na 2 TiO 3 , CaTiO 3 , K 2 TiO 3  and TiO 2 . 
     
     
         4 . The method of  claim 1 , wherein in step 1) the oxidation and enrichment is carried out at a temperature of 1100-1500° C. for 5-10 hours. 
     
     
         5 . The method of  claim 1 , wherein in step 2) the titanium-enriched slag is pulverized to 100-300 mesh, and the drying is carried out at 100-300° C. 
     
     
         6 . The method of  claim 1 , wherein in step 4), a vacuum degree is 0.2-0.3 MPa; a mole percentage of the titanate C is 1-10 mol %; the molten salt medium comprises a compound D having a mole percentage of 50-100 mol % and a compound E having a mole percentage of 0-40 mol %; and a dehydrating temperature is 150-350° C. 
     
     
         7 . The method of  claim 1 , wherein in step 5) the reducing agent is selected from sodium, calcium or magnesium, and the inert gas is argon at a flow rate of 1-30 mL/s. 
     
     
         8 . The method of  claim 1 , wherein in step 6) a vacuum drying temperature is 30-50° C., and a vacuum degree is 0.2-0.5 MPa. 
     
     
         9 . The method of  claim 6 , wherein the compound D is selected from one or more of CaCl 2 , NaF and KF; and the compound E is selected from one or more of NaCl, KCl, LiCl and NaAlO 2 .