WASTEWATER TREATMENT PROCESS

摘要

Provided is a wastewater treatment method capable of selectively and efficiently separating and removing high-purity manganese sediment from sulfuric acid acidic wastewater containing aluminum, magnesium and manganese. In this wastewater treatment for a sulfuric acid acidic wastewater containing aluminum, magnesium and manganese, a magnesium oxide is used as the entire amount or a portion of the added neutralizer, said magnesium oxide being produced by steps (1) to (4) below. (1) Effluent wastewater obtained by separating the aluminum and manganese from sulfuric acid acidic wastewater is concentrated and the calcium contained in the effluent wastewater is precipitated as calcium sulfate, (2) the solution obtained in (1) is further concentrated and the magnesium is precipitated and separated as magnesium sulfate, (3) the magnesium sulfate separated in (2) is roasted together with a reducing agent to obtain magnesium oxide and sulfurous acid gas, and (4) the magnesium oxide obtained in (3) is washed.