TW342382B - A recycling process of spent copper etchant for electronic industry - Google Patents

Abstract

A recycling process of spent copper etchant for electronic industry, which comprises: (a) neutralizing the spent copper etchant forming a weak acid to weak alkali (pH being 3.5~8), and forming a precipitate; (b) after the neutralization and precipitation of step (a), separating the mixture into a solid portion containing a high content of copper and a liquid portion containing a low content of copper; (c) recycling the solid portion containing a high content of copper and washing it with water to form a main ingredient of an insecticide with economic value for sale, and producing a solution containing a small amount of copper ; (d) recycling the liquid portion containing a low content of copper of step (b), and incorporating it with the water-washed solution containing a small amount of copper of step (c), and extracting the mixture with an extracting agent of R-H organic liquid resin (containing amines, oximes and derives thereof, or diketones, cyclic carboxylic acids, phosphoric acid esters) to obtain an oil phase product containing copper and a water phase product containing a minute amount of copper; (e) analyzing the NH4Cl content of the water phase product containing a minute amount of copper of step (d), and based on the analysis result, taking a fixed volume of the water phase product and adding it with an appropriate amount of additives including ammonium chloride, ammonium water, etc. and mixing the mixture to prepare a copper etchant to be reused by the electronic industry; then, concentrating the remaining water phase product containing a minute amount of copper by evaporation into an ammonium chloride crystal to be recycled by a centrifuge; furthermore, during the recycling process of evaporation concentration for producing the ammonium chloride (NH4Cl) crystal, when the content of Cu+2 in the mother liquid exceeds 2000 ppm, introducing it to the liquid portion of step (b) and the solution containing a small amount of copper of step (c) to be mixed and used as the solution for extraction in step (d); (f) adding an appropriate amount of hydrochloric acid into the copper-containing oil phase product of step (d) for reverse extraction, and obtaining a water phase copper chloride solution and an oil phase product containing a small amount of copper in which the water phase copper chloride solution can be recycled to step (a) for neutralization, and the oil phase product containing a small amount of copper can be re-introduced to step (d) for extraction.