Process for recycling alkali waste etching liquid

Abstract

The invention discloses a process for recycling alkali waste etching liquid. The process comprises the following steps of: acidizing and regulating the pH value; separating solid and liquid; purifying and converting; and recycling supernatant liquid. By adopting the process for recycling the waste alkali etching liquid, copper ions in the waste alkali etching liquid can be recovered, and the supernatant liquid can be recycled; the process has zero waste water discharge, thereby reducing the production cost of enterprises; and the waste liquid can be utilized 100 percent to guarantee no pollution.

Description

technical field [0001] The invention relates to a waste liquid recovery process, in particular to a cyclic recovery process for alkaline etching waste liquid. Background technique [0002] At present, PCB production has formed a large-scale industry in my country, with an annual output of 200 million m 2 , PCB production produces a large amount of etching solution. PCB etching solution mainly includes alkaline etching solution and acid etching solution. The total copper content of etching waste solution is about 50,000 tons per year. These etching solutions have the characteristics of various types, high toxicity and strong corrosiveness. They belong to the national first-class hazardous waste. If they are discharged arbitrarily without treatment, they will cause extremely serious damage to the ecology, and even seriously threaten the safety of people's lives. If the waste liquid cannot be effectively recycled, it will also cause a large amount of water pollution. [0003]...

AI Technical Summary

Problems solved by technology

For example, the Chinese invention patents, application numbers 91100122.0 and 200710030323.5, both use acidic etching solution and alkaline etching solution to neutralize directly. This method only involves copper recovery, and the waste solution cannot be recycled.

The method is to neutralize the alkaline etching solution with one to twice the acidic etching solution to obtain copper salt precipitation, etc. The recovered copper salt is cupric chloride ammonium, but after the copper salt in the etching solution is precipitated by this method, These upper waste liquids are difficult to recycle because the waste acidic etching liquid contains a large amount of accumulated sodium salt (introduced by oxidant).

However, the upper waste liquid contains tens of thousands of PPM of ammonia nitrogen, thousands of PPM of copper, and tens of PPM of organic matter. If it cannot be reused, it will seriously increase the burden of waste water on customers. Due to the serious pollution of the upper waste liquid, the treatment cost is astonishing. The production cost of the enterprise cannot be reduced, which increases the burden on the enterprise. What is more serious is that it is difficult to pass the treatment of the upper waste liquid using the most advanced treatment technology at present, which causes great hidden dangers to environmental protection.

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