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A kind of preparation method of ammonium paratungstate

A technology of ammonium paratungstate and sodium tungstate, which is applied in the field of ammonium paratungstate preparation, can solve the problems of complex process, high energy consumption, and high cost, and achieve the effects of reducing environmental pollution, simple process, and low cost

Active Publication Date: 2014-10-22
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, when the above method is used in industry to prepare ammonium paratungstate, the alkali in the production system is converted into NaCl or Na 2 SO 4 Waiting for salt, it is difficult to economically recycle, resulting in serious environmental problems caused by emissions
[0003] In order to realize the recycling of alkali, methods such as concentrated crystallization, membrane electrolysis, and solvent extraction of sodium tungstate solution under alkaline conditions have been proposed. These methods have problems such as high energy consumption, high cost, or low alkali recycling rate. At the same time, ammonium paratungstate The preparation is also through the process of sodium tungstate-ammonium tungstate-ammonium paratungstate, the process is more complicated and the process is longer

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Dissolve analytically pure sodium tungstate in pure water to prepare WO 3 It is 300g / L sodium tungstate solution. Take 100mL sodium tungstate solution and (NH 4 ) 2 CO 3 Placed in a reaction kettle with a volume of 150mL, (NH 4 ) 2 CO 3 The amount of addition is based on 120% of the stoichiometric conversion of tungstate radicals into ammonium paratungstate in the solution, and the reaction is carried out by feeding carbon dioxide gas into the closed reactor. The reaction temperature is 45°C, the pressure of the reaction system is 0.02MPa, and the stirring rate of the reactor is 120rpm. After 7 hours of reaction, the aeration is stopped, and the slurry obtained after the reaction is filtered. The filter cake is first cleaned with 40% NH 4 The Cl solution was washed twice according to the liquid-solid ratio of 10, then filtered and washed with pure water, and the ammonium paratungstate product was obtained after drying. The crystallization rate of tungsten is 80.4...

Embodiment 2

[0017] Dissolve analytically pure sodium tungstate in pure water to prepare WO 3 It is 150g / L sodium tungstate solution. Take 100mL sodium tungstate solution and NH 3 ·H 2 O is placed in a reaction kettle with a volume of 150mL, NH 3 ·H 2 The amount of O added is based on 150% of the stoichiometric conversion of tungstate radicals into ammonium paratungstate in the solution, and carbon dioxide gas is introduced into the reaction vessel after the closed reactor. The reaction temperature is 20°C, the pressure of the reaction system is 0.4MPa, and the stirring rate of the reactor is 120rpm. After 10 hours of reaction, the aeration is stopped, and the slurry obtained after the reaction is filtered. The filter cake is first cleaned with 40% NH 4 The Cl solution was washed twice according to the liquid-solid ratio of 10, then filtered and washed with pure water, and the ammonium paratungstate product was obtained after drying. The tungsten crystallization rate is 82.0%, and the...

Embodiment 3

[0019] Dissolve analytically pure sodium tungstate in pure water to prepare WO 3 It is 370g / L sodium tungstate solution. Take 100mL sodium tungstate solution and (NH 4 ) 2 CO 3 and NH 4 HCO 3 The mixture (molar ratio 1:2) was placed in a reaction kettle with a volume of 150mL, (NH 4 ) 2 CO 3 and NH 4 HCO 3 The amount of addition is based on 120% of the stoichiometric conversion of tungstate radicals into ammonium paratungstate in the solution, and the reaction is carried out by feeding carbon dioxide gas into the closed reactor. The reaction temperature is 70°C, the pressure of the reaction system is 1.0MPa, and the stirring rate of the reactor is 120rpm. After 16 hours of reaction, the aeration is stopped, and the slurry obtained after the reaction is filtered. The filter cake is first cleaned with 40% NH 4 The Cl solution was washed twice according to the liquid-solid ratio of 10, then filtered and washed with pure water, and the ammonium paratungstate product was ...

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PUM

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Abstract

The invention discloses a preparation method of ammonium paratungstate. The preparation method comprises the following steps of: (1) preparing sodium tungstate-ammonium solution; (2) filling carbon dioxide under a pressure of 0.02-6 Mpa into the sodium tungstate-ammonium solution, maintaining temperature for 1-72 hours at a temperature of 20 to 100 DEG C, and obtaining slurry liquid containing rough ammonium paratungstate crystals; (3) carrying out solid-liquid separation on the slurry liquid, and returning the separated solution to a tungsten concentrate decomposing process; (4) and firstly washing solid obtained by separation in the step (3) by ammonium salt solution, wherein the washing temperature is 20 to 100 DEG C, then washing the solid by water to obtain the ammonium paratungstate. According to the preparation method of the ammonium paratungstate, the ammonium paratungstate is prepared by adopting the carbon dioxide to react with a sodium tungstate-ammonium solution system and carrying out direct crystallization. The preparation method of the ammonium paratungstate has the advantages that the alkali circulation in the tungsten extraction metallurgical process is realized, the environment pollution is reduced, the process is simple, the energy consumption is low, the cost is low, and the like.

Description

technical field [0001] The invention relates to a preparation method of ammonium paratungstate. Background technique [0002] Tungsten metallurgical process The preparation of ammonium paratungstate from sodium tungstate solution mainly goes through two steps, the preparation of pure ammonium tungstate solution and the crystallization of ammonium paratungstate. Among them, there are three main methods for the preparation of pure ammonium tungstate: 1) ion exchange method, through ion exchange, the tungstate in sodium tungstate solution is separated from impurities and converted into ammonium tungstate solution; 2) solvent extraction method, mainly Transform sodium tungstate solution into ammonium tungstate; 3) Classical method, the purified sodium tungstate solution is transformed into ammonium tungstate solution through steps such as precipitation to synthesize artificial scheelite-acid decomposition-ammonia dissolution. The preparation of ammonium paratungstate by ammoniu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G41/00
Inventor 李小斌周秋生师琪彭志宏刘桂华齐天贵
Owner CENT SOUTH UNIV