| CPC C22B 47/00 (2013.01) [C22B 3/02 (2013.01); C22B 3/26 (2021.05); C22B 3/44 (2013.01); C22B 23/0407 (2013.01)] | 8 Claims |

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1. A method for recovering manganese from a high-pressure leaching system of laterite nickel ore, comprising the following steps:
S1. adding limestone to the high-pressure leaching solution of the laterite nickel ore for preneutralization to obtain first-stage carbon dioxide and a neutralization solution, adding limestone in the neutralization solution 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 the nickel-cobalt-manganese precipitated lean solution, adjusting the pH value of the nickel-cobalt-manganese precipitated lean solution to 5-6.5 by using liquid alkali, and then performing a precipitation reaction to obtain a crude manganese carbonate; and
S3. dissolving the crude manganese carbonate by using 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.
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