Preparation method of low-potassium low-sodium low-chloride high-purity ammonium paratungstate

Abstract

A preparation method of low-potassium low-sodium low-chloride high-purity ammonium paratungstate is characterized in that wolframite concentrate and scheelite concentrate are taken as raw materials, the content of impurities in such auxiliary materials as deionized water, ammonium sulfide, copper sulfate and a strippant is controlled, and high-purity ammonium paratungstate is prepared by the procedures of ore blending and ball milling, soda boiling for decomposition, ion exchange, molybdenum removal, crystallization, drying and the like. During conversion between a prepeak solution and a high peak solution in the desorption process, the concentration of WO3 is larger than 100 g / l; during conversion between the prepeak solution and a rear section solution, the concentration of WO3 is larger than 150 g / l; the concentration of WO3 in the taken high peak solution is larger than 220 g / l, wherein K<=5 mg / l, Na<=15 mg / l and Cl<=15 g / l. The content of total impurities in high-purity ammonium paratungstate prepared by the method can be controlled within 70 ppm, which is far lower than the demand for the content (smaller than 177 ppm) of total impurities in zero grade products of the 'paratungstate' national standard (GB / T10116-2007), particularly, Na<=2 ppm, K<=3 ppm and Cl<=10 ppm.

Description

technical field [0001] The preparation method of low-potassium, low-sodium, low-chlorine, high-purity ammonium paratungstate of the present invention mainly involves the preparation of high-purity ammonium paratungstate with a content of total impurities within 70ppm, especially Na≤2ppm, K≤3ppm, and Cl≤10ppm, using mixed tungsten concentrate as raw material , specifically belonging to the technical field of inorganic materials. Background technique [0002] Tungsten is a very important strategic resource. With the development of tungsten follow-up product technology, high-end cemented carbides such as tungsten wire, tungsten powder, and tungsten rod have continuously increased requirements for raw material ammonium paratungstate. The existing national standard zero-grade ammonium paratungstate is no longer available. To meet the requirements of high-end cemented carbide, it not only puts forward certain requirements on the impurities and physical properties of ammonium parat...

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Problems solved by technology

[0002] Tungsten is a very important strategic resource. With the development of tungsten follow-up product technology, high-end cemented carbides such as tungsten wire, tungsten powder, and tungsten rod have continuously increased requirements for raw material ammonium paratungstate. The existing national standard zero-grade ammonium paratungstate is no longer available. To meet the requirements of high-end cemented carbide, it not only puts forward certain requirements on the impurities and physical properties of ammonium paratungstate, but also some enterprises that produce high-end products put forward particularly strict requirements on individual impurity elements, such as Sino-German joint venture Shitai Kejiang Tungsten Special Tungsten (Ganzhou) Co., Ltd. has strict requirements on the content of K and Na in ammonium paratungstate. When producing tungsten oxide and tungsten powder, due to the low melting point of K and Na, K and Na will form a molten state during roasting, making the crystal grains Mutual bonding, forming agglomeration phenomenon, which is not conducive to the control of cemented carbide crystal form and appearance

Zigong Cemented Carbide Co., Ltd. has strict requirements on the content of Cl in ammonium paratungstate. This is mainly because during the roasting process, the higher the content of chloride ions, the more corrosive to the furnace tube, which seriously affects the service life of the equipment.

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