Central South University

Jiangtao Li

Zhongwei Zhao

Xuheng Liu

Xingyu Chen

Yongli Li

Wanhai Xiao

Fenglong Sun

Lihua He

Zhichao Li

Muye Cui

Yongjin Luo

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 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.

Method for extracting tungsten from scheelite

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Changsha, China

Jiangtao Li