Alkaline three-in-one grinding process capable of integrating pretreatment of aluminum with on-line recycle of aluminum hydroxide

Abstract

The invention discloses an alkaline three-in-one grinding process capable of integrating pretreatment of aluminum with on-line recycle of aluminum hydroxide. The process comprises a medicament recycling system and two flowing water washing tanks, wherein the medicament recycling system comprise an alkaline three-in-one grinding tank and a stagnant water washing tank subsystem which are connected in series oppositely; the liquid in the alkaline three-in-one grinding tank is alkaline liquid and contains sodium nitrate of which the concentration is 40g/L to 80g/L; the ratio of the concentration of sodium nitrate to the concentration of free alkali is equal to 1; the stagnant water washing tank subsystem comprises a first stagnant water washing tank and a second stagnant water washing tank which are connected in series oppositely; the start end, along the water flowing direction, of the second stagnant water washing tank is also provided with a water replenishing hole and a third valve; the two flowing water washing tanks are connected in series oppositely. The alkaline three-in-one grinding process capable of integrating pretreatment of aluminum with on-line recycle of aluminum hydroxide, disclosed by the invention, has the characteristics that the aluminum alloy surface quality is improved, a grinded surface is uniform and smooth, grains are grinded completely, few industrial waste residues are generated, medicament consumption is low, scale formation and blocking are prevented, on-line recycle of the alkaline liquid and the aluminum hydroxide is realized and the like.

Description

technical field [0001] The invention relates to the technical field of aluminum alloy anodic oxidation surface pretreatment, in particular to aluminum pretreatment, aluminum hydroxide online recovery and alkaline three-in-one sanding process. Background technique [0002] The traditional aluminum alloy alkali etching process has been used for more than 100 years. Alkali etching has the disadvantages of high aluminum consumption, high alkali consumption, more alkali slag, difficult process control, many defects, high production cost, and large environmental pollution, which has long been recognized by the industry. Existing standard alkali etching and oxidation line slot layout image 3 As shown, among them, 4#, 7#, 10#, 13# and 16# tanks are working tanks, each working tank is equipped with two flowing water washing tanks, 9 slots are required for pre-oxidation treatment, and 4# alkali etching tank is The main working tank for surface pretreatment. The functions of each ta...

AI Technical Summary

Problems solved by technology

There are the following deficiencies: 1. For aluminum materials that have been stored for a long time, the oil removal is not good, the natural oxide film cannot be removed completely, the alkali corrosion is uneven, the surface of the aluminum material appears different luster, and the oxidation coloring is uneven; 2. The oil removal tank contains 150- 200g / L sulfuric acid is easy to bring into the alkali corrosion tank to neutralize caustic soda; in order to strengthen the degreasing ability, some manufacturers add about 5-15g / L ammonium bifluoride in the degreasing tank to completely eliminate the hidden danger of degreasing, but increase the treatment Fluorine and ammonia nitrogen wastewater pressure

[0040] 2. The process is complicated and there are many slots

There are a total of 9 slots in front of the oxidation tank, 3 working tanks, and 6 washing tanks, which are too complicated;

[0041] 3. Low efficacy

It takes a long time, which seriously restricts the production capacity of the oxidation line;

[0042] 4. There are many working slots, and the consumption of chemicals is large

1#, 4#, and 7# are working tanks, and the total chemical consumption is 60-80 kg / ton of material. In order to treat the wastewater containing these chemical agents, the aluminum material factory will spend more cost;

[0043] 5. There are many washing tanks and large water consumption

In addition to water costs, the treatment and discharge of these waste waters require additional environmental protection costs;

[0044] 6. The 1# tank contains fluorine, which hinders the reuse of wastewater;

[0045] 7. Tanks 1# and 7# contain ammonia nitrogen, making wastewater treatment even worse

Adding complexing agent to the alkaline etching tank, the aluminum ions are separated and separated, and the dissolution and carry-out of aluminum can achieve a dynamic balance. In addition to meeting the requirements for the appearance quality of aluminum materials, the bath management is very simple, but a fatal defect is ignored, that is, high Alkaline etching solution with high aluminum ion concentration and high viscosity is brought into 5# and 6# mobile washing tanks, and enters the waste water center to form industrial waste residue, which not only wastes aluminum resources, but also brings huge environmental protection treatment pressure

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