How to Produce High-Purity Manganese Sulfate - 3 Methods Compared

Market Production Methods for High-Purity Manganese Sulfate

High-Purity Manganese Sulfate (32% Mn, Ca/Mg Impurities ≤50ppm) – Key Manganese Source for Precursor & Battery-Grade Mn3O4, Future Applications in LMFP & Sodium-Ion Batteries Currently, there are three primary industrial methods for producing high-purity manganese sulfate, each with distinct advantages and limitations:

1. Recrystallization Method

Process:

· Sulfuric acid leaching of manganese ore → Iron & heavy metal removal → High-pressure/high-temperature or vacuum evaporation crystallization.

· The slurry from the first crystallization is filtered to obtain manganese sulfate crystals, which are then redissolved in water for a second crystallization.

· Repeat recrystallization 3–4 times to separate Ca, Mg, K, Na, and other impurities.

Disadvantages:

· High cost and low product quality (heavily dependent on ore quality and recrystallization frequency).

· Low manganese recovery rate (<50%), with over 50% of Mn remaining in the mother liquor.

· Impurities (especially soluble MgSO₄) accumulate in the mother liquor, making it unsuitable for industrial-grade MnSO₄ production.

2. Solvent Extraction Method

Process:

· Manganese ore leachate is treated with extractants (e.g., P507, P204) to separate Mn from Ca, Mg, K, and Na.

· Activated carbon removes organics to obtain "purified" MnSO₄ solution.

Disadvantages:

· Low technical barrier, but poor product quality due to incomplete Ca/Mg separation (no highly efficient extractant exists).

· Moderate cost, with Mn recovery rate <80%.

3. Fluoride Precipitation Method (Most Widely Used Industrial Approach)

Process:

· Fluorides (typically MnF₂) are added to precipitate Ca/Mg (CaF₂/MgF₂ have much lower solubility than MnF₂).

· Filtration removes Ca/Mg, followed by solvent extraction to eliminate residual fluoride.

· pH adjustment using high-purity MnO, then organic removal via activated carbon.

Advantages:

· Mature technology, yielding low-impurity products (except fluoride traces).

Disadvantages:

· Environmental hazards: Fluoride-containing wastewater & solid waste (classified as hazardous).

· High complexity & cost: Requires pH adjustments and premium MnO.

· Ore selectivity: Unsuitable for rhodochrosite (high soluble Mg) or low-grade pyrolusite.

Conclusion:
Different manufacturers adopt varying processes based on raw material availability, cost considerations, and environmental compliance. Fluoride precipitation dominates industrial production despite its environmental challenges, while extraction and recrystallization remain niche due to quality or yield limitations.