Treatment And Utilization Of Micro-Etching Waste

Printed circuit board is an integral part of the electronic products. Along with the development of the manufacturing industry in printed circuit board, the amount of waste mainly containing copper in the production process increases year by year. Compared with the mature treatment of high copper content of acidic and basic copper chloride liquid waste, comparatively less investigation has been made on the low copper content of the micro-etching liquid waste. For the purpose of the effective recovery copper resources and protection of the environment, a new technology for comprehensive utilization of micro etching liquid waste was set up.In this study, crude copper oxide was used to neutralize the acid in the micro-etching liquid waste and hydrogen peroxide which was contained in micro-etching waste was used to remove divalent iron ion by oxidating trivalent iron ion. At the same time, hydrogen peroxide was decomposed by using catalysis of copper oxide. A new technology of meta-titanic acid adsorption iron was put forward for micro-etching liquid waste on the basis of the current effect of iron removal process. The sodium carbonate used in the experiment contains a amounts of calcium, magnesium, iron impurities should be absorb by D403 macro porous chelating ion exchange resin, otherwise the product quality would be affected. Waste liquid which has been removed iron and sodium carbonate reacts to prepared copper carbonate products. The experimental results show that: D403big macro porous chelating ion exchange resin has good removal effect for cationic impurities in the industrial sodium carbonate solution, and the removal rate of impurities was over98%. The optimal condition of met titanic acid adsorbing iron could conclude to the adsorptive time is1h and the met titanic acid is250gram per liter micro-etching waste. The adsorption reaction is exothermic, so choose reaction at ambient temperature. Under above conditions, the removal rate of iron impurities was over96%. The appropriate reaction conditions of preparing basic copper basic copper carbonate is temperature70℃, pH8.5, washing frequency:3, liquid-solid ratio:1:10. Basic copper carbonate products prepared in this experiment are better than the export level of basic copper carbonate used for wood preservation and the chemical pure index of HG3-1075-77, and only SO42-does not meet the analysis pure index of HG3-1075-77.Other processing methods were explored on the micro etching waste using liquid acid retardation experiment and electrolysis experiment. The results showed that201×7strongly basic anion exchange resin can effectively block the acid in the micro-etching liquid waste. The best flow velocity is20mL·min-1. The best technology is alternating block and incomplete elution process. This process can effectively separate the acid in the micro-etching liquid waste and reduce water consumption. If the acid block process is before the process of preparation of copper salt, it not only can reduce the amount of alkali by the preparation of copper salt, but also recycle the acid partly. The best electrolytic condition of the micro-etching is that electrolytic time of2hours and current density of286A-m-2.