Method for extracting tungsten-molybdenum from high-molybdenum scheelite

Abstract

The invention relates to a method for extracting tungsten-molybdenum from high-molybdenum scheelite. The method comprises the following steps: leaching high-molybdenum scheelite with a sulfuric acid solution, and extracting molybdenum from the leaching liquid; extracting leaching residues with hydrogen peroxide so as to obtain a solution with peroxy-tungstate and peroxy-molybdate, and heating or introducing SO2 so as to obtain a solution with tungstate and peroxy-molybdate; dissolving the tungstate with hydrogen peroxide, heating the obtained solution, and introducing SO2 so as to obtain tungstate and a solution with peroxy-molybdate; repeating the operation for multiple times till pure tungstate is prepared; preparing tungsten trioxide or tungsten powder from the pure tungstate; heating the solution with the peroxy-molybdate, or introducing SO2, dissolving the obtained molybdate with a hydrogen peroxide solution so as to obtain a peroxy-molybdate solution, and performing ultrasonic spray pyrolysis, so as to obtain a molybdenum trioxide powder or a molybdate powder. The method is good in separation effect, simple in operation process, easy in operation process control, and easy inindustrial popularization and application.

Description

technical field [0001] The invention relates to the technical field of rare metal metallurgy, in particular to a method for extracting tungsten and molybdenum from high-molybdenum scheelite. Background technique [0002] At present, the mainstream technology for processing high-molybdenum scheelite in the industry is to first use alkaline reagents such as sodium hydroxide or sodium carbonate to obtain crude sodium tungstate solution and alkali boiling residue by pressure cooking. The crude sodium tungstate solution contains a certain amount of molybdenum, which needs to be vulcanized first, and then acidified to precipitate and separate molybdenum in the form of molybdenum trisulfide. This process will inevitably produce a large amount of toxic gas hydrogen sulfide. The acidified solution adopts a weakly basic extractant or a weakly basic ion exchange resin to absorb tungsten in it, and then back-extracts or desorbs with ammonia water to obtain an ammonium tungstate solutio...

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Problems solved by technology

This mainstream technology is currently facing several serious problems: First, alkaline pressure cooking needs to consume alkali such as sodium hydroxide or sodium carbonate. The cost of scheelite decomposition is very high; secondly, alkali pressure cooking will produce alkali cooking slag, which has been listed in the national hazardous waste catalogue, and tungsten smelting enterprises are not allowed to dispose of it at will, and must be handed over to qualified enterprises for paid treatment, and The state also charges 2,000 yuan / ton of environmental protection tax on the hazardous waste alkali cooking slag, which greatly increases the cost of tungsten smelting; third, in order to separate the associated molybdenum in scheelite, it is necessary to add sulfide to separate molybdenum by sulfide , the process will produce toxic gas hydrogen sulfide that will endanger production and the environment; fourth, in order to produce tungsten products with qualified impurity content, ammonia water or ammonium chloride and other ammonia reagents must be used as transformation reagents in the current tungsten smelting process , so the production process will inevitably produce a large amount of ammonia nitrogen wastewater, resulting in environmental pollution

Moreover, the main purpose of its invention is to separate tungsten and molybdenum according to the stability difference between peroxytungstic acid and peroxymolybdic acid in acidic solution, and does not involve the purification method of tungsten

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