Method for recycling tin and copper from PCB (Printed Circuit Board) tin waste liquid in cyclic regeneration manner

Abstract

The invention provides a method for recycling tin and copper from PCB (Printed Circuit Board) tin waste liquid in a cyclic regeneration manner, which comprises the following steps of: adding sulfuric acid and a filter aid into the PCB tin waste liquid to precipitate tin ions, and separating tin sulfate precipitate from supernate; adding the supernatant as a circulating separating agent into a new PCB tin waste liquid for precipitation separation of tin sulfate, and entering the next step until the copper content of the supernatant meets the requirement; oxalic acid and a filter aid are added into the supernate with the copper content reaching the standard, and copper ions are precipitated; and then the filtrate is subjected to regeneration liquid blending, and tin-stripping regeneration sub-liquid is obtained and returned to a production line for use. According to the method, metal ions tin and copper in the waste liquid can be selectively precipitated and separated, the tin content in the tin sludge and the copper content in the copper sludge are increased, the tin stripping liquid medicine can be regenerated and recycled, in the whole production process, no waste water is generated, the method is green and environmentally friendly, and the production cost is greatly reduced.

Description

【Technical field】 [0001] The invention relates to a method for recycling tin and copper of PCB tin waste liquid. 【Background technique】 [0002] The etching of the outer circuit of PCB enterprises uses electroplating pure tin (pattern electroplating process) as the protective layer of the circuit. After etching by the copper-ammonia-ammonium chloride alkaline buffer system, the tin protective layer on the surface of the circuit must be stripped (removing tin) process) and enter the next process. At present, all PCB companies basically use nitric acid-ferric chloride type tin stripping liquid. The tin stripping waste liquid contains 60-80g / L tin, 10-20g / L iron, 5-6.5mol / L nitrate and a small amount of organic additives such as benzotriazole for copper protection. [0003] The traditional nitric acid + ferric nitrate type tin stripping water uses the strong oxidizing property of nitric acid, supplemented by the oxidizing property of Fe3+. The potion first corrodes the tin on ...

AI Technical Summary

Problems solved by technology

[0005] 1. There are many impurities in the tin mud (containing a large amount of copper and iron, etc.); 2. The tin content in the tin mud is not high, and the added value is low; 3. The raw materials in the potion are wasted, and the resources cannot be recycled; 4. Secondary pollution ( Total nitrogen is difficult to treat until it meets the discharge standard); 5. Nitrogen oxides in the waste gas cannot be recycled, and it is also difficult to clean up; 6. The procedures for transferring hazardous waste are very cumbersome and there are few counterpart companies with hazardous waste code qualifications. High cost; 7. There are large environmental safety hazards in the process of hazardous waste loading, unloading and transportation