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

A technology of sodium fluorosilicate and sodium sulfate, which is applied in the field of sodium fluorosilicate production from sodium sulfate wastewater

Active Publication Date: 2011-04-20
GANSU JINSHI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, the discharge of these waters will make the ground white and affect the ecological environment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] Get 1.6 liters (Na 2 SO 4 Content 4g / L), add 18ml fluosilicic acid wastewater (H 2 SiF 6 content of 360 g / L) wastewater, stirred and reacted for 120 minutes. Plate and frame filter, and wash the precipitate with 256 g of warm water at 40-60°C. Sodium fluorosilicate precipitation was dried with rotary kiln exhaust gas at 100°C hot air flow for 2 hours to obtain 8.5 grams of sodium fluorosilicate product (Na 2 SiF 6 content 99.28%), producing 1618 grams of 2.76% dilute sulfuric acid, which is used for the neutralization of sodium chromate alkaline solution in the sodium dichromate production line. The detection data is shown in Table 1 below.

Embodiment 2

[0027] Get 1.6 liters (Na 2 SO 4 Content 200g / L). Add 2.16 liters of fluosilicic acid waste water (H 2 SiF 6 Content 150 g / L), react for 90 minutes. Filter with a plate frame, and wash the precipitate with 1500 g of warm water at 40-60°C. Sodium fluorosilicate precipitation was dried with rotary kiln exhaust gas at 150°C hot air flow for 2 hours to obtain 428 grams of sodium fluorosilicate product (Na 2 SiF 6 Content 98.98%). Produce 3.336 kg of 6.6% dilute sulfuric acid, which is used for the neutralization of sodium chromate alkaline solution in the sodium dichromate production line. The detection data is shown in Table 1 below.

Embodiment 3

[0029] Get 1 liter (Na 2 SO 4 content 300 g / L). Add 676 ml of fluorosilicic acid (H 2 SiF 6 Content 450 g / L) waste water, react for 40 minutes. Filter with plate frame. Wash the precipitate with 1600 g of warm water at 40-60°C. Sodium fluorosilicate precipitation is dried with rotary kiln exhaust gas at 200°C hot air flow for 2 hours to obtain 400 grams of sodium fluorosilicate product (Na 2 SiF 6 Content 99.15%). Produce 1.278 kg of 16.2% dilute sulfuric acid, which is used for the neutralization of sodium chromate alkaline solution in the sodium dichromate production line. The detection data is shown in Table 1 below.

[0030] Table 1 Test data

[0031]

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PUM

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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...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/10
Inventor 韩登仑张忠元毛雪琴武平
Owner GANSU JINSHI CHEM
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