Patent ID: 9255013
Filing Date: 2016-02-09
CPC Classification: C01G,C01P,C22B,Y02P

Claim Text:
1. A method of producing (high-purity) hematite for ironmaking by a process of adding a mineral acid and an oxidant to ore containing iron and valuable metals and then leaching the valuable metals under high pressure and high temperature to form a leachate, the method further comprising the following steps (1) to (3): (1) a neutralization step of performing a two-stage neutralization process on to form a leach slurry, the two-stage neutralization having a first neutralization process in which magnesium oxide is used as the neutralizer, and following the first neutralization, a second neutralization in which magnesium hydroxide is used as the neutralizer depending on the concentration of free acid in the leachate; (2) a solid-liquid separation step of separating the leach slurry obtained in the neutralization step into a leach residue and leachate; and (3) a classification step of classifying the leach residue into hematite and gangue components.