Method for extraction and separation of tungsten and molybdenum from tungsten and molybdenum mixed solution

Abstract

The invention provides a method for extraction and separation of tungsten and molybdenum. Hydrogen peroxide is filled in the tungsten and molybdenum mixed solution, the pH value is regulated to be acidic, and the acid tungsten mixed solution is taken as a water phase feed liquid to carry out extraction and separation with an organic phase. The organic phase comprises trialkylphosphine oxide, tributyl phosphate and a diluting agent; the organic phase conducts the multi-stage extraction with the water phase feed liquid, molybdenum is extracted into the organic phase, and tungsten is left in a raffinate, so that the separation of tungsten and molybdenum is achieved. The load-bearing organic phase adopts an alkaline back-extraction agent to carry out back-extraction to obtain a molybdenum-contained solution, and the organic phase subjected to the back-extraction returns to the extraction process. Tungsten and molybdenum are extracted and separated in the tungsten and molybdenum mixed solution containing H2O2 by adopting a novel binary mixture extracting agent, the method has the advantages that extraction and the back-extraction are high in split-phase speed, the separation effect of tungsten and molybdenum is good, the tungsten co-extraction loss is low, the loss of the organic phase as well as the environmental pollution is low, the industrialization is easy to realize, and the method is especially suitable for separating tungsten and molybdenum in the tungstate solution with high molybdenum content.

Description

technical field [0001] The invention relates to a method for extracting and separating tungsten and molybdenum from a tungsten and molybdenum mixed solution. The invention belongs to the technical field of chemical extraction. Background technique [0002] Tungsten and molybdenum are important strategic rare metals and have a wide range of uses in industry. Tungsten and molybdenum belong to group VIB in the periodic table of elements. Due to the contraction of lanthanide, tungsten and molybdenum have very similar properties and are difficult to separate. Molybdenum is often associated with tungsten minerals, and many secondary resources (such as waste petroleum hydrogenation catalysts, waste cemented carbide) also contain tungsten and molybdenum. However, molybdenum is an impurity element that needs to be strictly controlled in tungsten metallurgy. For example, my country's national standard GB10116-2007 stipulates that the molybdenum content in 0-grade ammonium paratungst...

AI Technical Summary

Problems solved by technology

The method is to add H to the acidic tungsten-molybdenum mixed solution 2 o 2 Make tungsten and molybdenum form peroxo complexes of tungsten and molybdenum respectively, and then use phosphoric acid ester (such as tributyl phosphate TBP) or trialkylphosphine oxide (such as tributylphosphine oxide TBPO, trioctylphosphine oxide TOPO ) or tertiary amines (such as trioctylamine TOA) or quaternary ammonium salts (such as tetraoctyl ammonium sulfate) and other extractants under certain conditions preferentially extract molybdenum peroxygen complexes and separate them from tungsten. This method can effectively remove tungsten molybdenum in acid salt, but the co-extraction amount of tungsten is relatively large, and the above-mentioned extractant requires a higher concentration of extractant to obtain a better separation effect, and the higher concentration of extractant leads to Difficulty with phase separation (U.S. Pat. No. 4,275,039)

U.S. Patent U.S.Pat.No.4,275,039, in order to improve the phase separation problem in the extraction process, use the three-component mixed extractant to replace the single-component extractant, that is, by D 2 EHPA, TBP, and TBPO are mixed in a certain proportion to form a three-component mixed extractant, which effectively solves the problem of phase separation and reduces the H in the process. 2 o 2 However, the problem of large co-extraction of tungsten has not been solved, and the composition of the organic phase is too complicated, which is not conducive to the realization of industrialization

Li Weixuan and others reported "selective extraction and separation of W and Mo from acidic solution" in "Rare Metals" (No. 3, 1989: 3-4). This paper selected TRPO (trialkylphosphine oxide)-MIBK-kerosene system in The extraction and separation of tungsten and molybdenum was studied under the condition of hydrogen peroxide complexation. The separation effect of tungsten and molybdenum is good, and the loss of tungsten co-extraction is small, but MIBK (methyl isobutyl ketone) has a large water solubility, a large loss of organic phase, and subsequent processing is complicated.

The research objects of the above methods are all tungstate solutions with high molybdenum content (Mo / WO 3 >2%), but the above methods all have problems such as large tungsten co-extraction loss, difficult phase separation, serious loss of organic phase, etc., so there are very few reports of industrial application