A REUSING METHOD OF WASTE NITRIC ACID BY ETCHING PROCESS AS ETCHING SOLUTION AND ALUMINUM SULFATE COAGULANT

摘要

PURPOSE: A method for reusing a waste etching solution containing nitric acid with an etching solution and an aluminum sulfate water treatment coagulant is provided to reduce a cost required to the treatment of waste acid, and to solve a problem of sludge reclamation. CONSTITUTION: The method for reusing a waste etching solution containing nitric acid comprises: a first step for manufacturing an aluminum sulfate solution by dissolving an aluminum component such that the density of aluminum in sulfuric acid is 10 to 60g/l; a second step for separating the waste etching solution containing aluminum and nitric acid generated from an etching process of an aluminum foil into a nitric acid solution and an aluminum nitrate waste solution by using a diffusion dialysis method; a third step for mixing the aluminum sulfate solution and the aluminum nitrate waste solution, heating the mixture at 100 to 200deg.C to evaporate the nitric acid, and cooling them to withdraw the nitric acid and to transpose the aluminum nitrate into the aluminum sulfate; and a fourth step for adjusting a density of the nitric acid into a range of 130 to 150g/l so as to use it as an etching solution, and adjusting a density of the aluminum sulfate solution into a range of 35 to 45g/l so as to use it as an aluminum sulfate water treatment coagulant.