Method for preparing alkaline etching liquid by using constant boiling hydrochloric acid

A technology of etching solution and hydrochloric acid, which is applied in the field of preparing alkaline etching solution from dilute waste hydrochloric acid, can solve the problems of low HCl recovery rate and high energy consumption, and achieve the effects of reducing environmental pollution, reducing manufacturing costs, and high etching efficiency and precision

Active Publication Date: 2013-07-31
XILONG SCI CO LTD
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Problems solved by technology

[0003] CN1562732A discloses a method for preparing concentrated hydrochloric acid by semi-continuous extraction and distillation of dilute waste hydrochloric acid. Sulfuric acid is used as the extraction agent, dilute waste hydrochloric acid is added semi-continuously into boiling sulfuric acid aqueous solution and the sulfuric acid aqueous solution is always in a boiling state, and the process is carried out at normal pressure or under reduced pressure. Extractive distillation, the distillate is gaseous hydrogen chloride, which is concentrated hydrochloric acid after being absorbed by dilute hydrochloric acid. This method consumes a lot of energy
[0004] CN101955157A discloses a method for recycling low-concentration waste hydrochloric acid containing NaCl. The waste hydrochloric acid containing NaCl is subjected to one-time distillation to desalinate to obtain dilute hydrochloric acid not containing NaCl. The dilute hydrochloric acid is put into a secondary distillation kettle, and CaCl is added 2 2H 2 O, carry out secondary distillation, absorb the front cut of secondary distillation with the dilute hydrochloric acid of primary distillation, obtain the higher hydrochloric acid of concentration, the recovery rate of this method HCl is low

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  • Method for preparing alkaline etching liquid by using constant boiling hydrochloric acid
  • Method for preparing alkaline etching liquid by using constant boiling hydrochloric acid

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Embodiment 1

[0015] Acid preparation: pump 16 tons of industrial azeotropic hydrochloric acid (HCl weight content 21%) into a 20 cubic meter acid storage tank, adjust the acid concentration to Cl － The content is 190g / L.

[0016] Neutralization: The acid liquid passes through the absorption tower in the spray state, and ammonia gas is passed into the absorption tower to form an ammonium chloride solution with pH=6.5.

[0017] Impurity removal: Add 2 liters of 30% hydrogen peroxide aqueous solution and 1 kg of activated carbon to the above ammonium chloride solution, pump and circulate for 30 minutes, and then filter into the quantitative tank with a plate and frame machine.

[0018] Synthesis: Add 14 kg of potassium nitrate and 12 kg of dipotassium hydrogen phosphate to the filtrate, continue to spray and absorb ammonia gas until the pH of the solution is 10±0.2, and filter the solution to obtain about 20 tons of alkaline etching solution.

[0019] The product inspection results are as fo...

Embodiment 2

[0022] Acid preparation: pump 16.37 tons of industrial azeotropic hydrochloric acid with a HCl weight content of 20.3% into a 20 cubic meter acid liquid storage tank, and adjust the acid liquid to Cl － The content is 188 g / L.

[0023] Neutralization: The acid solution passes through the absorption tower in the spray state, and ammonia gas is passed into the absorption tower to form an ammonium chloride solution with pH=6.7.

[0024] Impurity removal: Add 2 liters of 30% hydrogen peroxide aqueous solution and 1 kg of activated carbon to the ammonium chloride solution, pump and circulate for 30 minutes, and then filter it into the quantitative tank with a plate and frame machine.

[0025] Synthesis: Add 14 kg of potassium nitrate and 12 kg of dipotassium hydrogen phosphate to the filtrate, then continue spraying and absorbing ammonia through the absorption tower until the pH of the solution is 10±0.2, and filter the solution to obtain about 20 tons of alkaline etching solution. ...

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Abstract

The invention discloses a method for preparing an alkaline etching liquid by using constant boiling hydrochloric acid. The method comprises that: constant boiling hydrochloric acid is adjusted with water to obtain an acid liquid with a Cl<-> content of 185-195 g/L, the acid liquid absorbs ammonia gas to form an ammonium chloride solution, the ammonium chloride solution is added with a hydrogen peroxide aqueous solution and active carbon, stirring and filtration are sequentially performed, the filtrate is added with potassium nitrate and dipotassium hydrogen phosphate, and the obtained filtrate absorbs ammonia gas to obtain the alkaline etching liquid so as to change dilute waste hydrochloric acid into treasure.

Description

technical field [0001] The invention relates to environmental protection engineering, in particular to a method for preparing alkaline etching solution by using dilute waste hydrochloric acid produced in the preparation process of concentrated hydrochloric acid. Background technique [0002] In the fine chemical industry, crude hydrochloric acid or industrial hydrochloric acid is used to prepare concentrated hydrochloric acid. A large amount of dilute waste hydrochloric acid will appear in the production process of concentrated hydrochloric acid. This kind of dilute waste hydrochloric acid is called azeotropic hydrochloric acid, and its HCl content is 21±0.5%. For the production of 37% hydrochloric acid, nearly 2 tons of azeotropic hydrochloric acid are produced for every 3 tons of concentrated hydrochloric acid produced, and contain a large amount of impurity metal ions, of which iron content> 0.18%, lead content> 0.002%, copper content> 0.004 %. As a corrosive l...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K13/00
Inventor 阎云朝林伟波李金荣郑鹤立郑安丽陈帆敏张树东
Owner XILONG SCI CO LTD
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