Method for preparing hydrogen fluoride from fluosilicic acid

A technology of hydrogen fluoride and fluorosilicic acid, applied in fluorine/hydrogen fluoride, hydrogen fluoride, silicon oxide, etc., can solve the problems of low product purity and harsh preparation process conditions, and achieve the effect of recycling

Inactive Publication Date: 2016-06-08
衢州市鼎盛化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the existing problems of harsh preparation process conditions and low product purity in the preparation of hydrogen fluoride from fluosilicic acid, the present invention proposes a method for preparing hydrogen fluoride from fluosilicic acid. Calcium oxide is recycled, and the purity of the final hydrogen fluoride product reaches more than 99.9999%

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Raw materials: (mass percentage) 1000 kg of 30% fluosilicic acid, 122 kg of liquid ammonia, and 350 kg of calcium oxide, which is obtained from the preparation of hydrogen fluoride from calcium fluoride.

[0036] Put fluosilicic acid and liquid ammonia into the ammoniation reactor for reaction, the reaction conditions are controlled at 60°C, pH 8.5, after the reaction is complete, pass through the filter to separate the silicon dioxide and ammonium fluoride solution. The separated ammonium fluoride solution is reacted with calcium oxide in a synthesis reactor, and the reaction conditions are controlled at 90°C. After the reaction is complete, dilute ammonia water and calcium fluoride are separated by solid-liquid separation equipment. The separated calcium fluoride is dried by a dryer, the drying temperature is controlled at 180°C, and then calcined in a calciner, the temperature of the calciner is controlled at 600°C, and finally passed into a fluidized reaction bed wit...

Embodiment 2

[0038] Raw materials: 1000kg of 30% fluosilicic acid, 122kg of liquid ammonia, 350kg of calcium oxide added for the first time. The calcium oxide comes from the calcium oxide obtained in the preparation of hydrogen fluoride from calcium fluoride.

[0039] Add fluosilicic acid and liquid ammonia into the ammoniation reactor for reaction, the reaction conditions are controlled at 120°C, pH 8.0, after the reaction is complete, pass through the filter to separate the silicon dioxide and ammonium fluoride solution. The separated ammonium fluoride solution is reacted with calcium oxide in a synthesis reactor, and the reaction conditions are controlled at 80°C. After the reaction is complete, dilute ammonia water and calcium fluoride are separated by solid-liquid separation equipment. The separated calcium fluoride is dried by a dryer, the drying temperature is controlled at 220°C, and then calcined in a calciner, the temperature of the calciner is controlled at 650°C, and finally pa...

Embodiment 3

[0041] Raw materials: 1000kg of 30% fluosilicic acid, 122kg of liquid ammonia, 350kg of calcium oxide added for the first time. The calcium oxide comes from the calcium oxide obtained in the preparation of hydrogen fluoride from calcium fluoride.

[0042] Fluosilicic acid and liquid ammonia are added into the ammoniation reactor for reaction. The reaction conditions are controlled at 150°C and pH 9.0. After the reaction is complete, pass through a filter to separate the silicon dioxide and ammonium fluoride solution. The separated ammonium fluoride solution is reacted with calcium oxide in a synthesis reactor, and the reaction conditions are controlled at 99°C. After the reaction is complete, dilute ammonia water and calcium fluoride are separated by solid-liquid separation equipment. The separated calcium fluoride is dried by a dryer, the drying temperature is controlled at 180°C, and then calcined by a calciner with a temperature of 550°C, and finally passed into a fluidized...

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Abstract

The invention provides a method for preparing hydrogen fluoride from fluosilicic acid, comprising the following steps: (1) enabling the fluosilicic acid as a raw material to react with liquid ammonia, thus obtaining an ammonium fluoride solution and a silicon dioxide solid; (2) enabling the ammonium fluoride solution obtained in the step (1) to react with calcium oxide, thus obtaining calcium fluoride and weak aqua ammonia; (3) rectifying to purify the weak aqua ammonia obtained in the step (1), thus obtaining liquid ammonia, and entering the step (1) for recycling; (4) sequentially drying and calcining the calcium fluoride obtained in the step (2), then leading into a fluidization reaction bed with superheated steam, thus obtaining the hydrogen fluoride and calcium oxide, and returning the step (2) to reuse the calcium oxide for recycling, wherein the calcium oxide reacting with the ammonium fluoride solution for the first time in the step (2) is from purchased calcium oxide, and the calcium oxide in the second and subsequent reactions is the calcium oxide in the step (4). The preparation method realizes recycling of the calcium oxide generated in the hydrogen fluoride preparation process, and the purity of the hydrogen fluoride reaches 99.9999% or more.

Description

technical field [0001] The invention belongs to the technical field of hydrogen fluoride preparation, and in particular relates to a method for preparing hydrogen fluoride from fluorosilicic acid. Background technique [0002] Hydrogen Fluoride (HydrogenFluoride), chemical formula is HF, molecular weight 20.01, soluble in water and ethanol. Anhydrous hydrogen fluoride (abbreviated as AHF) is a colorless transparent liquid under low temperature or pressure, with a boiling point of 19.4°C, a melting point of -83.37°C, and a density of 1.008g / cm 3 (water=1). It is highly volatile into white smoke at room temperature and normal temperature. Its chemical properties are extremely active and can react with alkalis, metals, oxides and silicates. Hydrogen fluoride is the basis of modern fluorine chemical industry and the most basic raw material for the production of elemental fluorine, various fluorine refrigerants, new fluorine-containing materials, inorganic fluoride salts, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/19C01B33/12
CPCC01B7/193C01B33/12C01P2006/80
Inventor 应盛荣姜战应悦
Owner 衢州市鼎盛化工科技有限公司
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