Central South University

Zhongwei Zhao

Yongli Li

Xuheng Liu

Jiangtao Li

Xingyu Chen

Wanhai Xiao

Fenglong Sun

Lihua He

Zhichao Li

Muye Cui

Yongjin Luo

Disclosed is a method for clean metallurgy of molybdenum, including steps: 1) roasting molybdenite with calcium to obtain calcified molybdenum calcine, and leaching the calcified molybdenum calcine with an inorganic acid to obtain a molybdenum-containing inorganic acid leachate; 2) extracting molybdenum in the leachate with a cationic extractant to obtain an organic phase loaded with molybdyl cations and a raffinate; 3) using a hydrogen peroxide solution as a stripping agent to obtain a molybdenum stripping liquor; and 4) heating the molybdenum stripping liquor to dissociate peroxymolybdic acid therein so as to form a molybdic acid precipitate, and then calcining to obtain a molybdenum trioxide product. The method solves the problem of ammonia nitrogen wastewater production and can also be used for the enrichment and recovery of rhenium.

Method for clean metallurgy of molybdenum

A method for crystallization of &#x3b2;-ammonium tetramolybdate includes: performing a stepwise pH-adjusting treatment of an ammonium molybdate solution via zoning to obtain the &#x3b2;-ammonium tetramolybdate. When feeding the ammonium molybdate solution into a reaction system from a first zone and then into second to sixth zones successively, pHof a resultant solution in the first zone is 7.0-6.0; pHof a resultant solution in the second zone is less than 6 and greater than or equal to 4; pHof a resultant solution in the third zone is less than 4 and greater than or equal to 2.5; pHof a crystallized slurry in the fourth zone is less than 2.5 and greater than or equal to 1; pHof a crystallized slurry in the fifth zone is 2.5-4.0; and pHof a crystallized slurry in the sixth zone is less than 2.5 and greater than or equal to 2.0.

Method for crystallization of &#x3b2;-ammonium tetramolybdate

The present invention relates to the field of ore smelting technology, and particularly provides a method and system for comprehensive recovery and utilization of copper-nickel sulfide ore. Under normal pressure, the method can be used to directly leach copper-nickel sulfide ore concentrate or low-grade nickel matte obtained by matte smelting of copper-nickel sulfide ore. In the leaching process, the leaching rate of nickel, cobalt and iron is up to 99% or more, and copper is hardly leached, whereby the deep separation of copper from elements such as nickel and cobalt is directly realized, and the huge system for copper-nickel separation in the conventional process is omitted. Moreover, noble metals are not leached, and almost all of them remain in the leaching slag with copper, so the destiny is simple.

Method and system for comprehensive recovery and utilization of copper-nickel sulfide ore

A preparation method of phosphotungstic acid includes mixing a mixed solution containing tungsten, phosphorus and an inorganic acid with an organic-alcohol-containing oil phase for extraction, stripping the obtained supported organic phase and distilled water according to an oil phase:aqueous phase volume ratio of 3:1 to 10:1 to obtain a stripping solution; and carrying out thermal evaporation crystallization or spray drying on the stripping solution to obtain a phosphotungstic acid crystal, wherein the organic alcohol is a C7-C20 alcohol. The inventors have found out that the addition of an inorganic acid to a solution of phosphorus or tungsten and the use of an organic alcohol as an extractant can achieve simultaneous and efficient extraction of phosphotungstic acid. It has also been found that the organic-alcohol-containing oil phase has excellent selectivity for phosphotungstic acid molecules in the mixed solution.

Preparation method of phosphotungstic acid

A method for extracting and enriching lithium, including: (a) providing an electrodialysis device including an electrodialysis cell; (b) dividing the electrodialysis cell into a lithium salt chamber and a brine chamber using an anion exchange membrane; (c) filling the brine chamber with salt lake brine; (d) filling the lithium salt chamber with a Mgfree supporting electrolyte solution; (e) placing a conductive substrate coated with an ion sieve in the brine chamber to operate as a cathode; (f) placing a conductive substrate coated with a lithium-intercalated ion sieve in the lithium salt chamber to operate as an anode; and (g) carrying out an electrodialysis.

Method and device for extracting and enriching lithium

A method for extracting tungsten from scheelite by: 1) adding a mixed acid including HSOand HPOto a decomposition reactor; 2) heating the mixed acid to a temperature of 70-100&#xb0; C.; adding scheelite while controlling the mixed acid present in an amount of 3-8 L per kg of scheelite; allowing the components in the decomposition reactor to react for 1-6 h, and filtering the resulting mixture to obtain a filtrate; 3) supplementing the filtrate with sulfuric acid consumed in the reaction; 4) crystallizing the filtrate to obtain phosphotungstic acid crystals and mother liquor; 5) dissolving the phosphotungstic acid crystals in water to obtain a phosphotungstic acid solution; 6) transforming the phosphotungstic acid solution into an ammonium tungstate solution for the purpose of preparing ammonium paratungstate; and 7) supplementing the mother liquor with phosphoric acid and water to an initial level and reusing the mother liquor for ore leaching.

Growing community of inventors

Hunan, China

Zhongwei Zhao