Wolframite Closed Acid Decomposition Method Improvement

Preparation of tungstic acid products in two ways: First, wolframite as the raw material of the classic process; second is scheelite as the raw material of acid production process. Wolframite classic raw material for the process specific process: milling → alkaline boil → purification → scheelite → acidification → dehydration drying → packaging.

closed acid decomposition image

The acidification process is based on open acidification reaction, which is carried out under atmospheric pressure. First, hydrochloric acid is added into enamel reaction pot to heat. Then, calcium tungstate and nitric acid are added to heat reaction, and hydrochloric acid and nitric acid are added in liquid state. Because hydrochloric acid and nitric acid are volatile, resulting in high consumption of hydrochloric acid and nitric acid. At the same time, due to the open heating and high energy consumption, hydrochloric acid and nitric acid volatilization will cause environmental pollution, and the cost of production is high.

Some scholars have proposed the use of closed acid decomposition of tungstic acid preparation, the use of closed acidification reaction, acid amine in the reaction step of adding amine, the method of stable quality, low energy consumption, safety and environmental protection. The process is mainly used as follows:

1.Mixing and heating, the ammonium nitrate and calcium tungstate slurry are stirred and dissolved, and hydrochloric acid is pumped into the reaction pan for heating.

2.Acidizing Reaction, mixing and heating the dissolved ammonium nitrate, calcium tungstate slurry and heated hydrochloric acid. Ammonium nitrate is added in an amount of 7 to 10% of the WO3 content in the calcium tungstate slurry, and the acidification reaction is carried out under the temperature of 100 to 130 ℃ and the pressure of 0.1 to 0.3MPa for 15 to 30 minutes to stop the heating;

3.Washing and dewatering, the acidified material is put from the bottom of the reaction pot to the rinse tank, and dehydrated water is used to wash and dehydrate.

4.Drying packing, the tungstic acid after dehydration is dried and packed, that is, the finished product of tungstate.

The method of closed acid decomposition of wolframite has the advantages of stable product quality, simple process, easy operation and high reliability, and effectively prolongs the service life of the equipment, reduces the consumption of hydrochloric acid and coal. Using nitric acid instead of nitric acid, it is not easy to volatilize, and the tail gas is recycled by hydrochloric acid cooler. The environmental pollution is reduced and the economic benefit is obvious.

The traditional wolframite acidification process using open acidification reaction, hydrochloric acid and nitric acid volatilization can cause environmental pollution, some scholars have proposed a closed acid decomposition of tungstic acid, in the process of adding nitrate, the method of stable quality, low energy consumption, safety and environmental protection.

 

 

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