Technique for recycling aluminum hydroxide from waste liquid for acid washing and alkaline washing aluminum-based material

Abstract

The invention relates to a technique for recycling aluminum hydroxide from acid washing waste liquor and alkaline washing waste liquor of an aluminum-based material. The technique is characterized by comprising the following steps of: (1) respectively pre-treating the acid washing waste liquor and the alkaline washing waste liquor of the aluminum-based material; (2) mixing and separating the pretreated acid washing and the alkaline washing liquor after being neutralized, discharging the waste water after reaching the standard and directly utilizing a filter cake - aluminum hydroxide as an industrial raw material. According to the technique, not only is a great amount of aluminum-based alkaline washing waste liquid and acid washing waste liquid successfully treated, but also byproducts can be recycled, no secondary pollution occurs, and the technical difficulty both at home and abroad for a long time can be solved. A pilot scale test shows that the technique is reasonable in design and easy to implement and has great social benefit, environmental-protection benefit and economic benefit.

Description

technical field [0001] The invention belongs to an industrial waste liquid treatment method, in particular to a process for recovering aluminum hydroxide from the waste liquid of pickling and alkaline washing of aluminum substrates. Background technique [0002] Before the surface coating, installation and oxidation treatment of the aluminum base material, the following treatment procedures are required: aluminum base material→alkali washing and degreasing→water washing→electrolytic roughening→water washing→anodic oxidation→water washing→sealing→drying. This produces large volumes of acidic and alkaline waste. Since aluminum is an amphoteric substance, it can react with both acid and alkali, so there are a large amount of aluminum ions in the alkaline washing waste liquid and acidic waste liquid. For example, during the alkaline cleaning process of producing PS plates, the loss rate of aluminum substrate aluminum will reach 2~12g / m 2 , the aluminum content in the alkaline ...

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: ①The added filter aids cause serious wear and tear on the equipment, and the equipment is easily damaged; ②The filter cloth is often blocked by oily components, and the filter cloth is replaced frequently; ③The salt in the filter cake seeps into the groundwater after being buried, causing groundwater Pollution; ④The wastewater still contains phosphorus, causing water pollution; ⑤The filter cake contains a large amount of aluminum hydroxide, which cannot be recycled due to its complex composition, resulting in waste of resources

The disadvantages of this method are: 1. adding stearic acid and other degreasers to the alkaline cleaning waste liquid, and the treatment cost is high; The silicon removal effect is poor, resulting in high silicon content in the recovered aluminum hydroxide; ③The amount of reducing agent added to the acid waste liquid is large, the cost is high, and new impurities are introduced, causing new pollution

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