Method for producing sodium fluosilicate by utilizing waste water containing sodium sulfate

Abstract

The invention discloses a method for producing sodium fluosilicate by utilizing waste water containing sodium sulfate. The method is as follows: generating the sodium fluosilicate by adopting the waste water containing sodium sulfate and fluosilicic acid as a side product for producing hydrofluoric acid as a raw material; and obtaining a sodium fluosilicate product by curing, filtering, cleaning and pneumatic drying. The dilute sulphuric acid as a side product is used for a production line of sodium dichromate. The method provided by the invention has the advantages that the industrial sodium sulfate waste water is utilized to produce the sodium fluosilicate, and the materials are all industrial waste water. The industrial waste water of the sodium sulfate is from waste water obtained by washing chromium sesquioxide produced by sodium dichromate or waste water generated for producing chromium salt, the fluosilicic acid is from waste water in the process for producing the hydrofluoric acid, the produced sodium fluosilicate is used as a commodity for sales, the dilute sulphuric acid as a side product is used for the production line of the sodium dichromate. By utilizing the method, the cost for treating the waste water treatment of the industrial sodium sulfate in the chromium salt industry is reduced, and the reutilization of water resources is realized.

Description

technical field

[0001] The invention belongs to a method for producing sodium fluorosilicate from industrial sodium sulfate wastewater in the chromium salt industry, in particular to a method for producing sodium fluorosilicate from sodium sulfate wastewater discharged from the production process of the chromium salt industry. Background technique

[0002] In the chromium salt industry, the sodium sulfate-containing wastewater produced by the washing process of dichromium trioxide produced by sodium dichromate and the washing process of basic sodium chromium carbonate produced by sodium chromium sulfate cannot be used due to the impurities that affect the quality of sodium dichromate. Return to the chromium salt system for recycling. In order to meet the discharge standards, most of the industrial sodium sulfate wastewater is treated by freezing crystallization or evaporative crystallization to remove sodium sulfate effluent. However, since the sodium sulfate in this wastew...