Process and system for recovering manganese from high-pressure leaching system of laterite nickel ore

Abstract

A process and system for recovering manganese from a high-pressure leaching system of laterite nickel ore, including the following steps: S1. adding limestone to the high-pressure leaching solution of the laterite nickel ore for pre-neutralization to obtain first-stage carbon dioxide and a neutralization solution, adding limestone for precipitation of iron and aluminum to obtain second-stage carbon dioxide and a slurry, and adding liquid alkali to the slurry for precipitation of nickel-cobalt-manganese to obtain nickel-cobalt-manganese hydroxide and a nickel-cobalt-manganese precipitated lean solution; S2. collecting first-stage carbon dioxide and second-stage carbon dioxide and passing same into a nickel-cobalt-manganese precipitated lean solution, adjusting the pH value of the nickel-cobalt-manganese precipitated lean solution to 5-6.5 by liquid alkali, and then performing a precipitation reaction to obtain a crude manganese carbonate; S3. dissolving the crude manganese carbonate with sulfuric acid to obtain a dissolution liquid and third-stage carbon dioxide, then removing calcium and magnesium from the dissolution liquid to obtain a manganese sulfate solution and then evaporating and crystallizing to obtain manganese sulfate crystals; recycling the third-stage carbon dioxide and introducing same into a nickel-cobalt-manganese precipitated lean solution; the recovery rate and utilization rate of manganese is high, and the carbon emission from laterite nickel ore leaching process is reduced.