CN1414120A

CN1414120A - Method of producing tungstic acid by closed type hydrochloric acid decompose tunstite

Info

Publication number: CN1414120A
Application number: CN02134061A
Authority: CN
Inventors: 苏连发; 孙林基; 张正枢
Original assignee: Zigong Cemented Carbide Co Ltd
Current assignee: Zigong Cemented Carbide Co Ltd
Priority date: 2002-11-15
Filing date: 2002-11-15
Publication date: 2003-04-30
Anticipated expiration: 2022-11-15
Also published as: CN1177944C

Abstract

A process for preparing tungstic acid from scheelite by decomposing it by hydrochloric acid in sealed condition includes such steps as adding hydrochloric acid and powered scheelite to reactor, sealing, thermal decomposing reaction while stirring, filter and washing to obtain H2WO4. Its advantages are high productivity, less consumption of hydrochloric acid and energy, and less environmental pollution.

Description

Method for preparing tungstic acid by closed hydrochloric acid decomposition of scheelite

Technical Field

The invention belongs to a method for producing tungstic acid in tungsten hydrometallurgy, in particular to a method for directly producing tungstic acid from scheelite or artificial scheelite (CaWO)₄) A method for preparing tungstic acid by decomposing hydrochloric acid. The tungstic acid prepared by the method can be used for the production of subsequent deep-processed products taking tungsten as a main component.

Background

In the tungsten hydrometallurgy process, as wolframite resources are gradually exhausted, the tungsten hydrometallurgy is also shifted to the tungsten ore and the artificial scheelite as main raw materials. The production of tungstic acid by using scheelite (powder) and artificial scheelite ore pulp is one of the key processes, and is also an important process for the subsequent deep processing of products with tungsten as a main component. The traditional method for preparing tungstic acid from scheelite is to add excessive hydrochloric acid directly into an open reactor (kettle) and decompose mineral powder or ore pulp at high temperature (boiling point temperature) and air draft to prepare tungstic acid, i.e. an acid decomposition method. The reaction formula is as follows:

although the method has the characteristic of simple process, the hydrochloric acid belongs to volatile acids, particularly in a boiling state; secondly, due to the open and negative pressure operation, about 20-25% of HCl and a large amount of heat energy are discharged through the flue. Therefore, the method has the disadvantages of more consumption of raw and auxiliary materials, high energy consumption, large environmental pollution, low productivity and the like.

The invention content is as follows:

the invention aims to improve and design a method for preparing tungstic acid by decomposing scheelite with closed hydrochloric acid aiming at the defects in the background art so as to achieve the purposes of reducing the consumption of hydrochloric acid and energy consumption, reducing environmental pollution, improving the decomposition treatment effect, speed and productivity and the like.

The solution of the invention is that hydrochloric acid and scheelite powder or artificial scheelite are added into a reaction kettle at first or simultaneously, the materials are heated and decomposed under pressure under the condition of stirring, and the reacted reactants are washed to obtain the target product.

Thus, the method of the present invention comprises:

A. preparing materials: firstly, placing raw material mineral powder in a ball mill, grinding the raw material mineral powder to fine powder with the granularity of 60-40 mu m, and weighing the fine powder for later use, or directly weighing artificial scheelite ore pulp for later use according to requirements, and weighing hydrochloric acid for later use according to requirements;

B. decomposition treatment: adding hydrochloric acid into a reaction kettle, sealing and preheating to 50-60 ℃, then sealing and adding weighed mineral powder or artificial scheelite pulp for later use, or simultaneously adding the weighed hydrochloric acid, mineral powder or artificial scheelite pulp into the reaction kettle, sealing, heating under stirring, and carrying out pressurized decomposition reaction for 60-90 minutes until the final acid value reaches 60-150 g/L; the reaction temperature is 100-140 ℃, and the pressure is 0.1-0.6 MPa;

C. filtering and washing: discharging the feed liquid after B decomposition into a filter under reduced pressure, introducing hot water, filtering, and washing to obtain solid tungstic acid (H)₂WO₄) And (5) producing the product.

The addition amount of the hydrochloric acid is determined by the HCl content and WO in scheelite₃The content molar ratio is 4-6: 1. And the rotating speed of the stirring condition is 60-90 r.p.m. The hydrochloric acid, the mineral powder or the artificial scheelite ore pulp is added into the reaction kettle at the same time, or the artificial scheelite ore pulp or the mineral powder is prepared into ore pulp and then is preheated and added into the reaction kettle with the hydrochloric acid at the same time. And introducing hot water, filtering and washing, wherein the water temperature is 80-95 ℃.

According to the invention, hydrochloric acid and scheelite powder or artificial scheelite are added into a closed reaction kettle, and are heated and decomposed under pressure under the condition of stirring, so that the scheelite decomposition efficiency is greatly improved, the consumption of hydrochloric acid is reduced, and the environmental pollution and the dissipation of heat energy caused by HCl gas are avoided. By adopting the method, the consumption of the hydrochloric acid can be saved by 30-35% compared with the background technology, the energy can be saved by about 30%, and the production efficiency can be improved by 25-30%. Therefore, the invention has the characteristics of low consumption of hydrochloric acid, low energy consumption, small environmental pollution, effective improvement of productivity and the like.

Example 1

The volume adopted in the present embodiment is 3m³An anticorrosive pressure reaction kettle which is lined with ethylene propylene diene monomer and is provided with a stirrer and a steam injection pipe is used as a decomposition reaction device. The production method comprises the following steps:

A. preparing materials: firstly, the material containing WO₃550kg of 65% of raw material scheelite powder is put into a ball mill and ground into fine powder with the granularity of 55-45 mu m for later use; the concentration is 31%800L (liter) of industrial hydrochloric acid for standby;

B. decomposition treatment: adding the hydrochloric acid to be treated into a reaction kettle, sealing and heating to 55 ℃, starting a stirrer, adding 550kg of concentrate powder to be used, and performing decomposition reaction at 120 ℃ and under the pressure of 0.2Mpa for 70 minutes;

C. washing and filtering: discharging the decomposed material liquid into a square vacuum filter under reduced pressure, filtering and washing with 90 deg.C hot water for 85 min, and filtering to obtain solid H₂WO₄And (5) producing the product.

The decomposition rate of the scheelite concentrate powder in the embodiment reaches 99.75%, and the product has uniform granularity, good water permeability and excellent quality.

Example 2

The volume adopted in this embodiment is 5m³The reaction kettle lined with polytetrafluoroethylene is used as a decomposition reaction device, and WO is adopted₃68 percent of ore pulp of the artificial scheelite is taken as a raw material, and the density of the ore pulp is 2.1. The production method comprises the following steps:

A. preparing materials: firstly, 2400L (liter) of industrial hydrochloric acid with the concentration of 31 percent is metered for standby application, and simultaneously, the ore pulp is 1.8m³Preheating;

B. decomposition treatment: adding the hydrochloric acid to be used and the ore pulp subjected to preheating treatment into a reaction kettle at the same time, and carrying out closed decomposition reaction for 80 minutes at 120 ℃ and under the pressure of 0.2 Mpa;

C. washing and filtering: the mixture was filtered and washed with hot water at 90 ℃ for 85 minutes, and the remaining process and parameters were the same as in example 1.

The decomposition rate of the embodiment reaches 99.73%, and the product has uniform granularity, good water permeability and excellent quality.

Claims

1. A method for preparing tungstic acid by decomposing scheelite with closed hydrochloric acid; the method is characterized by comprising the following steps:

A. preparing materials: firstly, putting raw material mineral powder into a ball mill to be ground into fine powder with the granularity of 60-40 mu m, or directly weighing scheelite ore pulp for later use according to requirements, and weighing hydrochloric acid for later use according to requirements;

B. decomposition treatment: adding hydrochloric acid into a reaction kettle, sealing and preheating to 50-60 ℃, then adding weighed mineral powder or artificial scheelite pulp for later use, or simultaneously adding the weighed hydrochloric acid, mineral powder or artificial scheelite pulp into the reaction kettle, sealing, heating under pressure and performing decomposition reaction for 60-90 minutes under the stirring condition until the final acid value reaches 60-150 g/L; the reaction temperature is 100-140 ℃, and the pressure is 0.1-0.6 MPa;

C. filtering and washing: dischargingthe feed liquid after B decomposition into a filter under reduced pressure, introducing hot water, filtering, and washing to obtain solid tungstic acid (H)₂WO₄) And (5) producing the product.

2. A process for preparing tungstic acid according to claim 1; it is characterized in that the addition amount of the hydrochloric acid is determined by the HCl content and WO in scheelite₃The content molar ratio is 4-6: 1.

3. A process for preparing tungstic acid according to claim 1; the stirring device is characterized in that the rotating speed of the stirring device is 60-90 r.p.m.

4. A process for preparing tungstic acid according to claim 1; the method is characterized in that hydrochloric acid, mineral powder or artificial scheelite ore pulp are added into a reaction kettle at the same time, or the artificial scheelite ore pulp or the mineral powder is prepared into ore pulp, preheated and then added into the reaction kettle with the hydrochloric acid at the same time.

5. A process for preparing tungstic acid according to claim 1; the method is characterized in that hot water is introduced for filtration and washing, and the water temperature is 80-95 ℃.