Total recycling method of PCB (printed circuit board) nitric acid type tin-lead stripping waste liquid

Abstract

The invention provides a total recycling method of a PCB (printed circuit board) nitric acid type tin-lead stripping waste liquid. Ferrous sulfate is used as a reaction agent and a settling agent to react with the nitric acid type tin-lead stripping waste liquid; a filter cake is acquired from a reaction liquid through filtering separation, and is cleaned for the extraction of solid-phase tin-lead mud; a filter liquid and a cleaning liquid are merged to serve as a mother liquid; then iron is used as a reducing agent and a displacing agent to extract sponge copper from the mother liquid until the residual copper content in the mother liquid is lower than 1mg/L; the sponge copper is rinsed by clear water; after the sponge copper is extracted, the iron content of the residual mother liquid containing a large quantity of ion and acid is regulated through ferric salt or ferrous salt, and the acid content is regulated through acid; and after the residual mother liquid is continuously aerated through air or oxygen gas, ferrous iron is oxidized, hydrolyzed and polymerized, so as to prepare modified polymeric iron which serves as a water purifying agent. Through the method, the nitric acidtype tin-lead stripping waste liquid is totally recycled, the extraction rates of tin, lead and copper respectively exceed 99.3 percent, 99.9 percent and 99.0 percent, the yield of the modified polymeric iron reaches 100 percent, and three wastes and efflux are avoided, so that the environment is protected, and sustainable development of the PCB industry is achieved.

Description

technical field [0001] The invention relates to a treatment and comprehensive utilization method of PCB nitric acid-type tin-lead stripping waste liquid, in particular to a full-resource method for PCB nitric acid-type tin-lead stripping waste liquid. Background technique [0002] With the continuous deepening of my country's reform and opening up and the steady development of the economy, the IT industry has become an important pillar industry in our country. With the vigorous rise of the IT industry, the printed circuit board (referred to as PCB) manufacturing industry is also growing rapidly at an alarming rate. As of 2005, there were more than 3,500 PCB companies of different sizes in my country, and the total output of PCB exceeded 1.05×10 8 m 2 , has become one of the most important PCB manufacturing centers in the world. [0003] In the PCB manufacturing process, processes such as tin-lead plating, pattern etching, and tin-lead stripping need to discharge a variety...

AI Technical Summary

Problems solved by technology

Although the added value of tin products has been improved, the cost is also high, and the recovery rate of tin, lead and copper is still low; metals are extracted by heavy catchers or sodium sulfide, because WSP contains a large amount of high iron and strong oxidant nitric acid, resulting in a great loss of reagents , and the follow-up treatment of each metal in the mixed sediment is extremely difficult, and it is even more difficult to make the waste water harmless; adding sulfuric acid to WSP can improve the extraction of lead, but the decomposition of nitric acid and the acid dissolution of stannic acid are intensified, which not only deteriorates the operating environment, Moreover, the load and difficulty of subsequent water treatment are greatly increased; the nitric acid is first distilled from WSP by distillation process, and then tin, lead and copper are separated by chemical precipitation process. The resource utilization rate of WSP has been greatly improved, but the equipment investment Large, high energy consumption, high overall cost, harsh operating environment, and serious pollution

Based on the research and development status of the past two decades at home and abroad and the current industrial reality, considering that WSP mainly includes tin-lead salts, copper salts, iron salts, nitric acid (salts) and additives (corrosion inhibitors\complexing agents, etc.), these components As a resource, it has high value, but as a pollutant, it is a hazardous waste, which requires high treatment costs and has potential safety hazards such as secondary pollution.

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