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Technique for preparing waterless hydrogen fluoride on high purity

An anhydrous hydrogen fluoride, high-purity technology, applied in the direction of fluorine/hydrogen fluoride, etc., can solve the problems of low industrial value of calcium sulfate, difficult to control the molar ratio, and harsh filtration environment, so as to achieve low product cost, reduce repair costs, and process simple effect

Inactive Publication Date: 2005-11-16
SICHUAN UNIV
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  • Abstract
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Problems solved by technology

The disadvantage of this process is that it is difficult to filter the silica gel generated by the hydrolysis of silicon tetrafluoride, which cannot be realized in industry.
[0023] The disadvantages of this process are: there is a large amount of ammonia water in the first reaction solution, and it is difficult to filter at the same time, and a large amount of water is required to wash the filter cake; the equimolar proportion of the second step is difficult to control. After the reaction is completed, there are a large amount of ammonia in the solution. In the presence of ammonia water, the filtration environment is harsh, and a large amount of water is required to wash the filter cake; after the third step, the filter cake contains a large amount of potassium fluoride, which needs to be washed, and it is difficult to filter at the same time
[0027] The disadvantage of this process is that the separation of the first step reaction is difficult in engineering; in addition, the industrial value of calcium sulfate generated is very low

Method used

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  • Technique for preparing waterless hydrogen fluoride on high purity
  • Technique for preparing waterless hydrogen fluoride on high purity

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0045] Take 5000 kg of 15% fluosilicic acid, add 816 kg of potassium chloride with a purity of 95%, the reaction temperature is 40° C., the time is 1 hour, and the liquid-solid ratio is controlled at 4.3. Filter after completion of the reaction, the filter cake weighs 1077 kg, and the filtrate contains 8.1% hydrogen chloride.

[0046] After mixing 1077 kg of precipitated potassium fluorosilicate with 490 kg of 98% sulfuric acid, they were calcined at 500° C. for 40 minutes. 874 kg of potassium sulfate was produced with a purity of 97.6%; the generated gas was condensed at -5°C for 3 hours and separated to obtain 176 kg of anhydrous hydrogen fluoride with a purity of 99.93%. Silicon tetrafluoride is cyclically dissolved in water to produce fluosilicic acid. The weight of fluosilicic acid is 5040 kg, and the concentration is 10%.

Embodiment 2

[0048] Take 2000 kg of 15% fluosilicic acid, add 380 kg of potassium sulfate with a purity of 94.6%, the reaction temperature is 40° C., the time is 1 hour, and the liquid-solid ratio is controlled at 4.1. Filter after completion of the reaction, the filter cake weighs 439.6 kg, and the filtrate contains 10.5% sulfuric acid.

[0049] After mixing 439.6 kg of potassium fluorosilicate with 195.5 kg of 98% sulfuric acid, it was calcined at 450° C. for 1 hour. 358.7 kg of potassium sulfate was produced with a purity of 95.2%; the generated gas was condensed at -5°C for 2 hours to obtain 73.8 kg of anhydrous hydrogen fluoride with a purity of 99.96%. Silicon tetrafluoride is cyclically dissolved in water to produce fluosilicic acid. The weight of fluosilicic acid is 1506 kg, and the concentration is 13.3%.

Embodiment 3

[0051] Take 5000 kg of 15% fluosilicic acid, add 750 kg of sodium sulfate with a purity of 98.2%, the reaction temperature is 40° C., the time is 1 hour, and the liquid-solid ratio is controlled at 6.0. Filter after completion of the reaction, the filter cake weighs 764.2 kg, and the filtrate contains 10.2% sulfuric acid.

[0052] After mixing 764.2 kg of sodium fluorosilicate with 402 kg of 98% sulfuric acid, it was calcined at 450° C. for 1 hour. 581 kg of sodium sulfate was generated with a purity of 97.34%. The generated gas was condensed at 0°C for 3 hours and separated to obtain 151.4 kg of anhydrous hydrogen fluoride with a purity of 99.98%. Silicon tetrafluoride is cyclically dissolved in water to produce fluosilicic acid. The weight of fluosilicic acid is 3680 kg and the concentration is 11.2%.

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Abstract

A process for preparing high-purity anhydrous hydrogen fluoride from the fluorosilicic acid as industrial by-product and concentrated sulfuric acid features that the fluorosilicid acid is deposited out in salt mode and the traditional fluorespar approach is then used. The generated sulfate as by-product can be used as precipitant of fluorosilicic acid system.

Description

1. Technical field [0001] The technical field of application of the present invention is inorganic salt industry and chemical fertilizer industry. 2. Background technology [0002] Anhydrous hydrogen fluoride (AHF) is a colorless fuming liquid below 20°C and is easy to polymerize. It can corrode silicon-containing substances and has a strong burn force on the skin. When it dissolves in water, it releases heat and generates hydrofluoric acid. It is a fluorinating agent for organic raw materials, which is used to produce refrigerant "Freon", fluorine-containing resin, organic fluoride and elemental fluorine. In the petrochemical industry, it is used as a liquid catalyst for the alkylation of aromatic hydrocarbons and aliphatic compounds to produce high-octane gasoline. When mining some ore deposits, corrode formations, extract rare elements and radioactive elements, raw materials for uranium hexafluoride needed in the atomic energy industry and nuclear weapon production, etc...

Claims

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Application Information

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IPC IPC(8): C01B7/19
Inventor 张志业陈欣王辛龙朱家骅魏芳菲韩秀峰
Owner SICHUAN UNIV
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