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Method for producing HCl (hydrogen chloride) from NaCl

A technology of sodium chloride and hydrochloric acid, applied in the direction of preparation of chloride, chemical instruments and methods, chlorine/hydrogen chloride, etc., can solve problems such as hindering the reaction and difficult to find a market

Inactive Publication Date: 2019-02-26
CENT SOUTH UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because sodium chloride solid is reacted with concentrated sulfuric acid to produce hydrochloric acid, the sodium sulfate solid produced by the reaction will wrap sodium chloride, seriously hindering the progress of the reaction, and the final reaction residue is a mixture containing sodium chloride, sodium sulfate and sulfuric acid , this kind of mixture is solid waste that is difficult to dispose of
If sodium chloride and dilute sulfuric acid are heated and reacted to produce hydrochloric acid, dilute hydrochloric acid is obtained, because 20.2% hydrochloric acid under normal pressure can form an azeotropic solution, dilute sulfuric acid reacts with sodium chloride, and generally only a concentration of less than 20.2% can be obtained Hydrochloric acid, and hydrochloric acid with a concentration of less than 20.2% is difficult to find a market

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Take 1500kg of industrial salt and add 1m 3 In the saturated sodium sulfate solution, slowly add 98% concentrated sulfuric acid according to 1.1 times of the theoretical amount of sodium chloride converted into sodium sulfate, and stir at 115°C for 2.5 hours to make the chlorine in it volatilize in the form of HCl gas, and the volatilized HCl gas Absorb it with water to obtain hydrochloric acid with a concentration of 30%. After the reaction is completed, filter to obtain a post-reaction liquid and a reaction residue. The solid-to-liquid ratio of the obtained reaction residue is 1:3g / mL, stirred and added to a saturated solution of sodium sulfate for washing, stirred at 85°C for 1.5h, and adjusted to pH 6.8 with sodium carbonate, filtered to obtain the refined liquid and refined sodium sulfate, the purity of the refined sodium sulfate> 99%, of which chloride content <0.1%.

Embodiment 2

[0026] Get 2t of industrial salt and stir it into the liquid after the reaction obtained in Example 1, slowly add 50% sulfuric acid according to 2.1 times of the theoretical amount of sodium chloride converted into sodium sulfate, stir at 165° C. for 1.5 h, and make the chlorine therein evaporate with HCl gas The form volatilizes, and the HCl gas that volatilizes is passed directly into the waste liquid that the NaCl concentration is 150g / L, cools to room temperature after the reaction finishes, and filters to obtain the liquid after the reaction and the reaction residue. After stopping feeding HCl gas, filter the waste liquid containing NaCl to obtain 1.93t industrial sodium chloride and a concentration of 6.8mol / L hydrochloric acid solution, the gained hydrochloric acid solution is used for mineral decomposition, and industrial sodium chloride is used as raw material for hydrochloric acid preparation. The resulting reaction residue was stirred and added to the refined liquid ...

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Abstract

The invention relates to a method for producing HCl (hydrogen chloride) from NaCl. The method comprises the following steps: mixing NaCl and H2SO4 in a saturated Na salt solution to convert NaCl in the Na salt solution into Na2SO4 salt and HCl gas, performing heating and stirring to promote volatilization of HCl gas, absorbing the volatilized HCl gas with water or an aqueous solution to obtain HClor a HCl-containing solution, performing filtering after the reaction, using an obtained filtrate as a mixed medium of NaCl and H2SO4 continuously, refining a filter cake with a saturated Na2SO4 saltsolution to obtain a qualified Na2SO4 salt product, and returning the refined solution to serve as a mixed medium of NaCl and H2SO4. No waste water, waste residues or waste gas is produced in the whole process. Cyclic utilization of Cl in a production system can be realized by combining with a process for treating a Cl-containing waste solution and recovering NaCl; the method has the advantages of being clean, environmentally friendly, economic, efficient and the like, and is particularly suitable for industrial application of resource treatment of the Cl waste solution in metallurgical and chemical enterprises taking HCl as a raw material.

Description

technical field [0001] The invention belongs to the field of metallurgy and chemical industry, in particular to a method for producing hydrochloric acid by using sodium chloride. Background technique [0002] Hydrochloric acid is an aqueous solution of hydrogen chloride (HCl), a monobasic inorganic strong acid. Hydrochloric acid is a commonly used raw material in the metallurgical and chemical industries. After hydrochloric acid is used, waste liquid containing metal chlorides is usually produced. Most metal chlorides have good solubility at room temperature, such as magnesium chloride, ferrous chloride, chlorine The solubility of calcium chloride is greater than 500g / L, and most metal chlorides are deliquescent, such as calcium chloride and magnesium chloride, which are difficult to preserve. Compared with other metal chlorides, sodium chloride has the following advantages: low solubility, its solubility at room temperature is only 360g / L, pure sodium chloride is almost no...

Claims

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Application Information

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IPC IPC(8): C01B7/03C01D5/06
CPCC01B7/035C01D5/06C01P2006/80
Inventor 王学文王懿何汉兵孟钰麒王明玉杜艳苹
Owner CENT SOUTH UNIV
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