A method for recovering valuable metallic elements of wasted acid solution for stainless steed

摘要

PURPOSE: A method is provided, for recovery of valuable metals such as chromium, nickel and manganese capable of recycling from acidic waste generated from the process for preparing stainless steel. CONSTITUTION: Metals are recovered by adding NaOH solution to an acidic solution generated from the process for preparing stainless steel to make pH of the solution 4.0-4.5, and thereby to precipitate iron ions in the form of iron hydroxide; filtering the iron hydroxide to remove it; adding NaOH solution to the acidic solution to make pH of the solution 6.5-10.0, and thereby to precipitate metals in the form of hydroxide to obtain a slurry; and filtrating the slurry to separate the hydroxide from the acidic waste, and then drying and heating the separated hydroxide. Preferably after filtrating the slurry, the waste is treated to make the pH below 4.0, and neutralized by using CaO to remove fluoride ion.