Method for extracting and separating tungsten and molybdenum from molybdenum-contained ammonium tungstate solution

Abstract

The invention discloses a method for extracting and separating tungsten and molybdenum from a molybdenum-contained ammonium tungstate solution. The method comprises the steps that bicarbonate containing trialkyl methyl ammonium and an organic phase of a carbonate composite extractant of the bicarbonate are used for making contact with molybdenum-contained ammonium tungstate feed liquid subjected to vulcanization and an ammonium bicarbonate-ammonium carbonate mixed detergent correspondingly for performing fractional extraction, the molybdenum is made to enter the organic phase, the tungsten remains in a water phase, and a high-purity ammonium tungstate aqueous solution and an organic phase loaded with pure molybdenum are obtained; and then, the organic phase loaded with the pure molybdenumis oxidized through a hydrogen peroxide solution, reextraction is performed by adopting an ammonium bicarbonate-ammonium carbonate mixed solution, a high-purity ammonium molybdate solution is obtained, and an organic phase after reextraction can directly return back to extraction for repeated use without needing treatment. The method has the characteristics that the tungsten and molybdenum mutualseparation depth is high, no detrimental impurity is introduced, and high-purity tungsten and molybdenum product liquid can be obtained simultaneously.

Description

technical field [0001] The invention relates to the field of rare metal extraction and separation in hydrometallurgy, in particular to a method for extracting and separating tungsten and molybdenum from molybdenum-containing ammonium tungstate solution. Background technique [0002] Tungsten and molybdenum are important strategic rare metals, which are widely used in cemented carbide, alloy steel, electronics, defense aviation, petrochemical and other fields. Molybdenum is an impurity element that needs to be strictly controlled in tungsten products, and tungsten is an impurity element that needs to be strictly controlled in molybdenum products. 3 Mass ratio) is not more than 0.002%, and the national standard GB / T3460-2007 stipulates that the tungsten content in zero-grade MSA (ammonium molybdate) products (W / MoO 3 mass ratio) is not more than 0.015%. However, tungsten and molybdenum belong to group VIB in the periodic table of elements, and the two often coexist in their ...

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Problems solved by technology

The limitations of the above research for removing molybdenum in ammonium tungstate solution are: (1) taking the chloride salt of quaternary ammonium salt as the extractant will inevitably introduce chloride ions in the ammonium tungstate solution, and chloride ions are corrosive, resulting in subsequent When the ammonium tungstate solution is evaporated and crystallized to produce APT, the equipment material needs to improve the corrosion resistance level; (2) In order to ensure the deep removal of molybdenum in the tungstate solution, co-extraction of tungsten must exist in the loaded organic phase, and the loaded organic phase is not washed or Adopt NaCl, NaOH solution to wash (washing effect is limited) and carry out stripping after, not only cause the loss of tungsten but also make to contain higher tungsten in stripping solution, cause molybdenum product grade to decline, be unfavorable for the raising of the added value of molybdenum product; (3 ) The stripping liquid that adopts alkaline NaClO solution back extraction to obtain is the sodium molybdate solution that contains a large amount of chloride ions, further processing prepares ammonium molybdate product cost height, and waste water amount is big

In view of the above problems, the separation method of tungsten and molybdenum based on thiomolybdate extraction with quaternary ammonium salt has been difficult to achieve industrial application so far.

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