Method for preparing hydrogen fluoride and sodium fluoride by use of fluosilicic acid

A technology of fluorosilicic acid and sodium fluoride, applied in the direction of fluorine/hydrogen fluoride, hydrogen fluoride, alkali metal fluoride, etc., can solve the problems of high impurity content of by-products, increase production cost, and small usable value, and achieve high product purity. , the effect of saving raw materials, good economic benefits and environmental benefits

Active Publication Date: 2017-01-25
张旭
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The above-mentioned patents may have organic pollution, or consume a large amount of concentrated sulfuric acid chemical raw materials to increase production costs, and the by-products have high impurity content, low usable value, and limited feasibility.

Method used

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  • Method for preparing hydrogen fluoride and sodium fluoride by use of fluosilicic acid

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Experimental program
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Embodiment 1

[0038] Preparation of hydrogen fluoride and sodium fluoride with fluorosilicic acid, the process flow chart is as follows figure 1 shown.

[0039] 1. For the first production cycle, follow the steps below:

[0040]1) Take 50 kg of fluorosilicic acid solution with a mass concentration of 20% and 8.0 kg of ammonium bifluoride, place them in a tetrafluoroethylene-lined still, set the temperature at 95° C., and distill for 5 hours. The fractions are condensed to obtain hydrofluoric acid solution, containing Hydrogen fluoride 5.5kg, the residue at the bottom of the kettle is ammonium fluorosilicate solid.

[0041] 2) Add 55 kg of ammonia water with a mass fraction of 25% to the bottom of the kettle, set the temperature at 30° C., and react for 120 minutes. Filter the reaction system to obtain white carbon black and a mixed solution containing ammonium fluoride and ammonia water. The mixed solution was heated for 90 minutes at a temperature of 220° C., ammonia gas was collected to...

Embodiment 2

[0052] 1. The first production cycle:

[0053] 1) Take 50kg of fluorosilicic acid solution with a mass concentration of 25% and 14.8kg of ammonium bifluoride, place it in a still lined with tetrafluoroethylene, set the temperature at 140°C, and distill for 2.5h. The fractions are condensed to obtain hydrofluoric acid containing Hydrogen fluoride 6.9kg, the residue at the bottom of the kettle is ammonium fluorosilicate solid.

[0054] 2) Add 30 kg of ammonia water with a mass fraction of 25% to the bottom of the kettle, set the temperature at 65° C., and react for 60 minutes. Filter the reaction system to obtain white carbon black and a mixed solution containing ammonium fluoride and ammonia water. The mixed solution was heated for 240 minutes at a temperature of 110° C., ammonia gas was collected to obtain ammonia water, and the solid ammonium bifluoride product was weighed to obtain a mass of 19.6 kg.

[0055] 3) Take 4.8 kg of ammonium bifluoride obtained in step 2) and dis...

Embodiment 3

[0063] 1. The first production cycle:

[0064] 1) Take 50 kg of fluorosilicic acid solution with a mass concentration of 15% and 5.4 kg of ammonium bifluoride, place them in a tetrafluoroethylene-lined distillation kettle, set the temperature at 150°C, and distill for 1 hour. The distillate is condensed to obtain hydrofluoric acid containing 3.8% hydrogen fluoride kg, the residue at the bottom of the kettle is ammonium fluorosilicate solid.

[0065] 2) Add 11.0 kg of ammonia water with a mass fraction of 25% to the bottom of the kettle, set the temperature at 70° C., and react for 60 minutes. Filter the reaction system to obtain a mixed solution containing white carbon black and ammonium fluoride and ammonia water. The mixed solution was heated for 150 minutes at a temperature of 180° C., ammonia gas was collected to obtain ammonia water, and the solid ammonium bifluoride product was weighed to obtain a mass of 8.1 kg.

[0066] 3) Take 2.7 kg of ammonium bifluoride obtained i...

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Abstract

The invention discloses a method for preparing hydrogen fluoride and sodium fluoride by use of fluosilicic acid. The method comprises the following steps of: adding ammonium bifluoride into fluosilicic acid for reaction, and performing distillation, thereby obtaining a hydrogen fluoride gas and an ammonium fluosilicate solid; 2) adding aqueous ammonia into ammonium fluosilicate for reaction, performing filtration to obtain white carbon black, heating and distilling a filtrate to obtain an ammonia gas and an ammonium bifluoride solid; and 3) reacting the ammonium bifluoride obtained in the step 2) with sodium carbonate or sodium bicarbonate, filtering the filtrate after reaction is over, thereby obtaining a sodium fluoride precipitate, distilling the filtrate, and collecting the ammonia gas. The method is wide in raw material source, low in cost, low in equipment requirement, less in pollution and low in energy consumption, is capable of repeatedly using ammonium bifluoride and aqueous ammonia and converting ammonium bifluoride and sodium carbonate or sodium bicarbonate into sodium fluoride and hydrogen fluoride which are relatively high in application value and wide in application range, and has favorable economic benefits and environmental benefits.

Description

technical field [0001] The invention belongs to the field of inorganic chemical production, and in particular relates to a method for preparing hydrogen fluoride and sodium fluoride from fluorosilicic acid. Background technique [0002] Fluosilicic acid is an inorganic dibasic strong acid, mainly from the by-products of the phosphate fertilizer industry, which contains useful elements fluorine and silicon. my country is a country with large phosphate rock resources, and the annual production of by-product fluosilicic acid is huge, and the average production of per ton of general calcium (P 2 o 5 100%) is produced with 0.06t of fluosilicic acid (100%). At present, most of them are used to produce sodium fluorosilicate, but the added value is low. If it is used reasonably, it will definitely produce huge economic and environmental benefits. [0003] Sodium fluoride is an important chemical raw material, which can be used to manufacture other fluorides, fungicides, insectici...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/19C01D3/02C01B33/12
CPCC01B7/193C01B33/12C01D3/02C01P2006/80
Inventor 张旭魏瑶
Owner 张旭
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