Method for producing hydrogen chloride and sodium hydrogen sulfate crystals by taking rock salt as raw material

A technology of sodium bisulfate and sodium sulfate, applied in the direction of sulfate/bisulfate preparation, chlorine/hydrogen chloride, etc., can solve the problems of unfavorable transfer and packaging, easy hardening and water absorption of salt, complex operation process, etc., to prevent crystallization The effect of tower condition, avoiding dissolution loss, and simple production process

Inactive Publication Date: 2012-03-07
HUAIYIN TEACHERS COLLEGE +1
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Problems solved by technology

Concentrated acid high-temperature method is to add concentrated sulfuric acid and potassium chloride into a high-temperature reaction kettle (250°C) to remove hydrogen chloride above the melting point of bisulfate. ammonium potassium fertilizer intermediate, and the by-product hydrogen chloride is a high-temperature corrosive gas containing dust, and the post-processing device is complicated
The dilute acid low temperature method is to use 60-75% dilute sulfuric acid and chloride to strip hydrogen chloride with water vapor at about 120°C to generate a bisulfate aqueous solution containing excess sulfuric acid. Compared with the high temperature method, the operating temperature is low and the investment is relatively low. , but, the reaction time is longer (2-5h), the energy consumption is still higher, and the bisulfate aqueous solution of generation is because solution concentration is thinner, and chlorine content is higher, therefore, in order to reach the chlorine content requirement of direct use, It is bound to introduce a large amount of steam in the later stage of the reaction to remove residual hydrogen chloride, thereby increasing the cost
Concentrated acid low-temperature method is to prepare a phase-transfer dispersion medium aqueous solution composed of excess sulfuric acid and corresponding bisulfate in a reaction kettle, add measured chlorides into the reaction kettle under stirring conditions, heat up to boiling, and then add to the reaction Gradually add sulfuric acid equivalent to the chloride in the kettle, after the sulfuric acid is added, keep warm for 30-35 minutes, then cool to normal temperature, filter the crystalline bisulfate and wash with water to obtain the finished product bisulfate, and recycle the mother liquor. The operability in production is enhanced compared with the previous two types of methods, but there are following problems: the feeding and reaction operation process is relatively complicated; in this method, water is used to wash the bisulfate product, resulting in product dissolution loss, and pressure filtration or suction filtration The final salt is easy to harden and absorb water, which is not conducive to transfer and packaging

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  • Method for producing hydrogen chloride and sodium hydrogen sulfate crystals by taking rock salt as raw material
  • Method for producing hydrogen chloride and sodium hydrogen sulfate crystals by taking rock salt as raw material

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Example 1: In a 50L glass-lined reactor with a stirred tank and a thermometer, add 6.00kg of 96% sulfuric acid first, then add 6.20kg of sodium chloride mixture with a mass percentage of sodium sulfate of 0.01%, and simultaneously start hydrogen chloride absorption or storage system; keep stirring at a constant temperature of 100°C, and add 12.39kg of 96% sulfuric acid, and keep warm for 30 minutes after adding acid; introduce the reaction solution into a crystallization tower containing 3.82kg of water, and first Stirring crystallization 5min, then static crystallization 5min, finally stirring crystallization 20min; Suction filtration and washing with saturated sodium bisulfate solution give sodium bisulfate crystal 14.52kg, analyze wherein sodium bisulfate crystal mass percentage composition is 96.98%, free acid (according to Sulfuric acid meter) mass percentage composition is 1.98%, and chloride ion mass percentage composition is 0.10%; Filtrate is mixed with the sulf...

Embodiment 2

[0023] Embodiment 2: Add 6.00kg 90% sulfuric acid earlier in the 50L glass-lined reaction kettle with stirring tank and thermometer, then add 6.20kg sodium sulfate mass percentage composition and be the sodium chloride mixture of 0.1%, open hydrogen chloride absorption simultaneously or Storage system; Stir continuously at a constant temperature of 110°C, and add 17.07kg of 90% sulfuric acid, keep warm for 25 minutes after adding acid; introduce the reaction solution into a crystallization tower containing 2.86kg of water, under the condition of condensed water temperature of 10°C, Stir and crystallize first 10min, then leave standstill to crystallize 10min, finally stir and crystallize 35min; Suction filtration and wash with saturated sodium bisulfate solution to obtain sodium bisulfate crystal 14.55kg, analyze wherein sodium bisulfate crystal mass percentage composition is 97.56%, free acid ( In terms of sulfuric acid), the mass percentage is 1.93%, and the chloride ion mass ...

Embodiment 3

[0024] Embodiment 3: Add 6.00kg90% sulfuric acid to a 50L glass-lined reactor with a stirring tank and a thermometer, then add 6.20kg of sodium chloride mixture with a mass percentage of sodium sulfate of 0.5%, and simultaneously start hydrogen chloride absorption or storage System; keep stirring at a constant temperature of 120°C, and add 22.77kg of 90% sulfuric acid, and keep warm for 20 minutes after adding acid; introduce the reaction solution into a crystallization tower containing 1.91kg of water, and first Stirring and crystallization 20min, then static crystallization 10min, finally stirring crystallization 45min; Suction filtration and washing with saturated sodium bisulfate solution to obtain sodium bisulfate crystal 14.51kg, analysis wherein sodium bisulfate crystal mass percentage composition is 97.47%, free acid (according to Sulfuric acid meter) mass percentage composition is 1.85%, and chloride ion mass percentage composition is 0.23%; Filtrate is mixed with the ...

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Abstract

The invention discloses a method for producing hydrogen chloride and sodium hydrogen sulfate crystals by taking rock salt as the raw material, which comprises the following steps that: the mixture of sodium sulfate and sodium chloride, i.e. rock salt and sulfuric acid react to produce the hydrogen chloride and sodium hydrogen sulfate crystals; first, under a stirring condition, according to a certain stoichiometric ratio, sulfuric acid and rock salt are intermittently added into a glass lining reaction vessel to react while the temperature is insulated; and then sodium bisulfate solution which contains sulfuric acid is introduced to a crystal tower which contains an appropriate amount of water from the bottom of the reaction vessel to be cooled, crystallized and vacuum filter step by step, and then is washed by saturated sodium bisulfate solution to prepare sodium bisulfate crystals; and finally, the high-concentration sulfuric acid is added into the filtrate to be mixed to be sulfuric acid with the initial reaction concentration, and recycled. The method of the invention not only makes full use of natural resources, but also improves the added value of the rock salt, does not discharge any waste liquid, and meets the requirements of sustainable development.

Description

technical field [0001] The invention relates to a production method of hydrogen chloride and bisulfate, in particular to a method for producing hydrogen chloride and sodium bisulfate crystals from rock salt. Background technique [0002] Hydrogen chloride gas is an important chemical raw material. With the increasing development of science and technology, fine chemical industries such as dyes, chloromethyl ether, anhydrous piperazine, cystine and pesticides, pharmaceutical intermediates and chlorinated polymers are more sensitive to hydrogen chloride. The demand is increasing. There are a lot of low-concentration hydrochloric acid discarded after pickling steel in iron and steel enterprises. Therefore, low-concentration hydrochloric acid can be used to absorb hydrogen chloride gas to increase the concentration, so that the discarded low-concentration hydrochloric acid can be recycled, thereby reducing the production cost and environmental treatment costs of steel enterprises...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B7/01C01D5/02
Inventor 褚效中张维光吕金顺赵宜江徐继明苏娟周守勇李梅生
Owner HUAIYIN TEACHERS COLLEGE
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