Method and equipment for preparing hydrogen fluoride from fluosilicic acid

A technology of hydrogen fluoride and fluosilicic acid, applied in the direction of fluorine/hydrogen fluoride, silicon oxide, silicon dioxide, etc., can solve problems such as excessive fluosilicic acid, achieve the effects of reducing emissions, increasing economic value, and saving energy

Pending Publication Date: 2018-01-19
衢州市鼎盛化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The present invention proposes a method and equipment for preparing hydrogen fluoride f

Method used

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  • Method and equipment for preparing hydrogen fluoride from fluosilicic acid
  • Method and equipment for preparing hydrogen fluoride from fluosilicic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Such as figure 1Shown: a device for preparing hydrogen fluoride from fluorosilicic acid, including a decomposition kettle 11 , a washing tower 12 , a condenser 13 , an absorption kettle 14 and a solid-liquid separation device 15 . Wherein the decomposition kettle 11, the washing tower 12, the condenser 13, the absorption kettle 14, and the separation device 15 are connected in sequence through pipelines. The decomposition kettle 11 is used for decomposing fluosilicic acid, which includes a first inlet 111 for concentrated sulfuric acid, an inlet 112 for concentrated fluosilicic acid, an outlet 113 for dilute sulfuric acid, and a first outlet 114 for mixed gas of silicon tetrafluoride and hydrogen fluoride. The washing tower 12 is used to absorb the moisture entrained in the mixed gas of silicon tetrafluoride and hydrogen fluoride, which includes the second inlet 121 of concentrated sulfuric acid, the first inlet 122 of the mixed gas of silicon tetrafluoride and hydrogen...

Embodiment 2

[0046] Adopt the equipment preparation among the embodiment 1, take fluosilicic acid as the concrete steps of raw material preparation hydrogen fluoride as follows:

[0047] Pass 1,000kg of 30% fluosilicic acid and 1,750kg of 98% concentrated sulfuric acid into the decomposition kettle 11, mix and react at 90°C, and the gas generated is passed into the washing tower 12, and the moisture entrained in the mixed gas of silicon tetrafluoride and hydrogen fluoride is absorbed by concentrated sulfuric acid , then enter the condenser 13, and the condensed liquid hydrogen fluoride passes into the liquid storage tank 17. The concentrated sulfuric acid in the washing tower 12 continues to be used in the decomposition kettle 11.

[0048] The uncondensed gas is passed into the absorption tank 14 that has 1000kg30% fluosilicic acid, and then the reactant is passed into the separation device 15, and the silicon dioxide precipitate is cleaned to obtain 41.7kg of silicon dioxide and 1175kg of...

Embodiment 3

[0051] Adopt the equipment preparation among the embodiment 1, take fluosilicic acid as the concrete steps of raw material preparation hydrogen fluoride as follows:

[0052] Pass 1175kg of 42.5% fluosilicic acid and 1746.4kg of 98% concentrated sulfuric acid into the decomposition kettle 11, mix and react at 90°C, the gas generated is passed into the washing tower 12 and condenser 13 in turn, and the condensed liquid hydrogen fluoride is refined 138.7 kg of anhydrous hydrogen fluoride were obtained. The concentrated sulfuric acid in the washing tower 12 continues to be used in the decomposition kettle 11.

[0053] The uncondensed gas is passed into the absorption tank 14 that has 1000kg30% fluosilicic acid, and then the reactant is passed into the separation device 15, and the silica precipitate is cleaned to obtain 69.4kg of silica and 1291.4 kg of 49% fluosilicic acid. kg. The fluosilicic acid continues to be reused as a raw material. This silica is available as a takeawa...

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Abstract

The invention provides a method and equipment for preparing hydrogen fluoride from fluosilicic acid. The method comprises the following steps: concentrated fluosilicic acid and concentrated sulfuric acid are mixed, after reaction, mixed gas of silicon tetrafluoride and hydrogen fluoride and dilute sulfuric acid are obtained; washing and condensation are carried out; silicon tetrafluoride gas is added into dilute fluosilicic acid, and silica solid and concentrated fluosilicic acid clear liquid are obtained. The equipment comprises the following components: a decomposing pot, a washing tower, acondenser, an absorption kettle and a separator, which are communicated in order. Substances generated in the steps can be used as raw materials, cost is saved, and at the same time post-treatment process is reduced, production efficiency is improved, and large scale application of factory is facilitated. Absorption function of concentrated sulfuric acid is used, fluosilicic acid is decomposed into hydrogen fluoride and silicon tetrafluoride gas, so that effective utilization of fluosilicic acid is obtained. Dilute sulfuric acid is concentrated into concentrated sulfuric acid again, dischargeof dilute sulfuric acid is reduced, sulfuric acid becomes an intermediate, and fluosilicic acid is decomposed into hydrogen fluoride and silica.

Description

technical field [0001] The invention relates to the technical field of hydrogen fluoride, in particular to a method and equipment for preparing hydrogen fluoride from fluorosilicic acid. Background technique [0002] In the process of using calcium fluoride and sulfuric acid to produce hydrogen fluoride, since calcium fluoride contains silicon dioxide, silicon dioxide reacts with hydrogen fluoride to form silicon tetrafluoride, and water and a small amount of hydrofluoric acid absorb silicon tetrafluoride together to make it Become a by-product of fluorosilicic acid. Due to the sharp shrinkage of the market volume of fluosilicic acid in recent years, fluosilicic acid has changed from a salable by-product to a waste acid that needs to be treated in an environmentally friendly manner; this increases the cost of production enterprises. [0003] In view of this, it is necessary to develop a process for treating fluosilicic acid to digest excess fluosilicic acid and produce othe...

Claims

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Application Information

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IPC IPC(8): C01B7/19C01B33/12
Inventor 周贞锋董寒杰应盛荣
Owner 衢州市鼎盛化工科技有限公司
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