Method for recycling alkali liquor in aluminum alloy section alkali corrosion production procedure

Abstract

The invention discloses a method for recycling alkali liquor in an aluminum alloy section alkali corrosion production procedure. The method comprises the following steps of S1, performing alkali corrosion on an aluminum alloy section; S13, after alkali corrosion is performed for 30-54 min, taking out an aluminum alloy section from a bath solution, and therefore completing alkali corrosion of the aluminum alloy section; S2, recycling a NaOH solution, wherein S21, the concentration of Al3+ in the bath solution is detected, when the concentration of Al3+ reaches 28 g / L, a pump is adopted for pumping the bath solution inside an alkali corrosion groove into a crystal separation groove; S23, the pump is adopted for pumping the supernate NaOH solution into a recycling barrel, then, the NaOH solution inside the recycling barrel is poured into the alkali corrosion groove to continue to be used for production, closed loop production is formed, and therefore the NaOH solution is recycled; S3, aluminum ions are recycled. The method has the beneficial effects that the section surface quality stability is improved, consumption of sodium hydroxide is lowered, later sewage treatment difficulty islowered, and economic benefits are improved.

Description

technical field [0001] The invention relates to a method for recovering and reusing alkali liquor in the alkali corrosion production process of aluminum alloy profiles. Background technique [0002] With the improvement of the production scale and product quality of my country's architectural aluminum profiles, the surface treatment process, quality and equipment have been in line with the international advanced level; with the increasing shortage of resources and energy, the continuous strengthening of environmental protection awareness and the optimization and reorganization of industrial production, aluminum profiles The production process has been developed in the direction of low energy consumption, low pollution, and green environmental protection. Under the premise of ensuring the performance, the impact of the anodic oxidation process on the environment is minimized. [0003] Before the chemical pretreatment of anodic oxidation surface treatment, it is necessary to ca...

AI Technical Summary

Problems solved by technology

A large amount of high value-added Al is produced in the alkali etching process 3 + If the tank liquid accumulates to a certain extent, it will precipitate, dehydrate, agglomerate and harden, and the combination with the tank wall is very firm, resulting in the need for a large amount of water to flush the alkali-etched tank, which has a great impact on production

Due to the large amount of Al 3 + The existence of aluminum ions combined with hydroxide ions in the NaOH solution, a large amount of NaOH solution was lost, the cost of alkali etching was increased, and a large amount of Al(OH) was produced in the bath after the combination 3 Slurry, which undoubtedly brings difficulties to the later sewage treatment

In addition, a large amount of Al 3 + The existence of aluminum alloy profiles makes the surface quality of aluminum alloy profiles unstable, and there are large differences, which reduces the quality of profiles

[0004] The bath solution used in alkali etching is NaOH solution and organic acid sodium salt solution. The organic acid sodium salt makes the aluminum ions produced in the alkali etching process complex with it to form NaAlO 2 , NaAlO 2 No or less hydrolysis, so that the Al(OH) generated by the initial hydrolysis 3 The crystal nucleus particles do not grow up, and even if they occur, they are soft precipitates instead of hard lumps, but it still cannot solve the problems of unstable surface quality of aluminum alloy profiles and large mud output

In order to solve the above problems, people add nitrate or nitrite to the bath, which can improve the surface brightness, but produce ammonia nitrogen pollution; add surfactant and tackifier, the sand surface effect of alkali etching will be better, but produce A large amount of sludge; some corrosion inhibitors are added to reduce the consumption of alkali, but there are still the following defects: (1) high viscosity: the bath solution of alkali corrosion additive can only be mixed with high concentration Al 3 + (100~150g / L) coexist, the lye can react uniformly and inhibit corrosion with the aluminum to achieve leveling effect, and the effect of alkali sand is better

(2) The temperature (50~75°C) and concentration (55~70g / L) of the alkali etching solution are relatively high; (3) The water consumption is large: the surface of the alkali etching aluminum material has a high concentration and viscosity of alkali solution, which needs to be strengthened wash with water

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