Patent ID: 9657370
Date: 2017-05-23
CPC Classifications: C02F,C22B,Y02P

Claim:
1. A method of removing manganese from a sulfuric acid waste water in which manganese is removed by precipitating manganese selectively from the sulfuric acid waste water containing aluminum, magnesium and manganese, comprising: (1) First, removing aluminum from said sulfuric acid waste water so that a concentration of aluminum is 0.1 g/L or less; (2) Subsequently, adding neutralizing agent into the sulfuric acid waste water after removing aluminum and adjusting a pH value of the sulfuric acid waste water to no less than 8.0 and less than 9.0; and (3) adding oxygen gas with a purity of 98 volume % or more into the sulfuric acid waste water, wherein manganese is precipitated in steps (2) and (3), and wherein in step (2), the pH value of the sulfuric acid waste water is adjusted to reach an equilibrium by adding neutralizing agent, prior to step (3) of adding the oxygen gas into the sulfuric acid waste water under a pressure load of 0.10 MPa to 0.20 MPa.