Production method of sodium fluosilicate

Abstract

The invention relates to a production method of sodium fluosilicate. The method comprises the following steps: adding a phosphoric acid purification device to purify the phosphoric acid produced in a phosphoric acid workshop; injecting the purified phosphoric acid in a filtrate receiver, injecting in a reaction tank by using a variable frequency pump; injecting fluorine-removing agent in the reaction tank at a ratio according to the fluorine content of phosphoric acid, reacting by utilizing the stirring action of the reaction tank; injecting the obtained mixture in a settling tank by using a pump after the reaction in the reaction tank, centrifuging the settled precipitate, and drying to obtain a sodium fluosilicate product and obtain the defluorinated phosphoric acid on the upper layer. In the method, after wet-process phosphoric acid is purified, fluorine-removing agent is used to remove about 2% of fluorine in phosphoric acid and form insoluble fluosilicate, and the fluosilicate is precipitated, washed, separated and dried to obtain a sodium fluosilicate product, thus the rational utilization of resource can be realized and the economic benefit of the enterprise can be increased. By adopting the method, fluorine resource can be fully recycled in the production process of compound fertilizer, high quality fluorine-free compound fertilizer can be produced and the damages to soil can be reduced or eliminated.

Description

technical field [0001] The invention relates to a method for producing sodium fluorosilicate, which belongs to the field of chemical product production. Background technique [0002] At present, the production of sodium fluorosilicate is generally produced by the reaction of phosphoric acid fluorine-containing tail gas in the production process of compound fertilizer or the fluosilicic acid produced in the process of phosphoric acid concentration with sodium sulfate or sodium chloride. The amount of acid is small, the output is low, and about 80% of the fluorine in phosphate rock exists in phosphoric acid during the production of phosphoric acid. Phosphoric acid is directly used to produce compound fertilizers, and the fluorine in it is not used. Into the soil to cause soil and environmental pollution, harmful to the human body. [0003] Phosphoric acid contains about 2% fluorine. During the production of compound fertilizer, the fluorine in phosphoric acid is lost in vain,...

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Problems solved by technology

[0002] At present, the production of sodium fluorosilicate is generally produced by the reaction of phosphoric acid fluorine-containing tail gas in the production process of compound fertilizer or the fluosilicic acid produced in the process of phosphoric acid concentration with sodium sulfate or sodium chloride. The amount of acid is small, the output is low, and about 80% of the fluorine in phosphate rock exists in phosphoric acid during the production of phosphoric acid. Phosphoric acid is directly used to produce compound fertilizers, and the fluorine in it is not used. Entering the soil, causing soil and environmental pollution, and causing harm to the human body

[0003] Phosphoric acid contains about 2% fluorine. During the production of compound fertilizer, the fluorine in phosphoric acid is lost in vain, resulting in waste of resources.

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