Aluminum and aluminum alloy etching clean production process

Abstract

The invention discloses an aluminum and aluminum alloy etching clean production process. The process comprises the following steps of (1) cooling and diluting, specifically, extracting a high-temperature etching liquid which accounts for 4%-5% of the total amount of the etching liquid in an etching tank from the etching tank by using a heat pump to a dilution precipitation tank, mixing in tap water while extracting, and controlling the volume ratio of the added tap water to the extracted etching liquid to be 1 to 1; (2) removing suspended matters by precipitation, specifically, after precipitating the cooled and diluted etching liquid for 3-5 hours, removing the suspended solids with large particles through sediment; (3) removing suspended matters by filtering, specifically, filtering supernatant liquid in a precipitation dilution tank by using filtering equipment to further remove fine suspended matters in the etching liquid, and separating out filtered filter residues; (4) pumping filtrate filtered in the step (3) back to the etching tank for recycling; and (5) repeating the steps (1)-(4) twice every day. According to the production process, the etching liquid is clean, the service life is prolonged, the etching speed is stable, and the etching quality is improved.

Description

Technical field [0001] The present invention belongs to the technical field of industrial wastewater treatment, and more particularly to an aluminum and alloys etching and cleaning production processes, extending the etching fluid life cycle. Background technique [0002] Etching is an important aluminum alloy processing method widely used in the aerospace industry. [0003] The chemical reaction type when aluminum and its alloy is etched as follows: [0004] 2A1 + 2NAOH + 2H 2 O ➝ 2NAA1O 2 + 3h 2 [0005] Naa1o 2 + H 2 O ⇋ A1 (OH) 3 + Naoh [0006] Metal impurities present in aluminum and alloys, in alkaline conditions and NA 2 In the presence of S, a precipitate is formed. [0007] ME 2+ + 2OH - ➝ME (OH) 2 ↓ [0008] ME 2+ + S 2- ➝mes ↓ [0009] During the aluminum alloy etching, aluminum is dissolved in etching liquid in Naalo 2 The form of Naalo 2 The generation will reduce the efficacy of the etching solution, as the etching is carried out, due to the constant dissolution o...

AI Technical Summary

Problems solved by technology

[0010] After the etchant fails, there is no very effective recycling method at present. It is only transported to the chemical waste dump (the invalid etchant is hazardous waste) for disposal, which brings economic and environmental pressure to the enterprise

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