Electrolytic manganese metal, abbreviated EMM, is manganese deposited from a manganese sulfate electrolyte and stripped from the cathodes as bright metallic flakes. The 99.7 percent grade is the most common commercial quality, and the flakes are used wherever manganese must be added with controlled chemistry and low impurity pickup. This article explains how EMM is produced, what a 99.7 specification contains, how the material is delivered, and where it is consumed.
How Electrolytic Manganese Metal Is Produced
EMM production follows a hydrometallurgical route. Manganese ore is leached with sulfuric acid to produce a manganese sulfate solution, which is purified to remove iron, heavy metals and other impurities. The purified solution is fed into electrolytic cells, where direct current deposits manganese metal onto stainless steel cathodes. After deposition, the metal is stripped from the cathodes in flake form, washed, dried and classified. Energy consumption is high, which makes electricity a major cost factor and links EMM prices to power availability in the producing regions.
Typical Specification of EMM 99.7
The table below shows typical commercial limits for the 99.7 grade. Actual limits are defined in the applicable standard and in the contract, and the certificate of analysis for each lot is the authoritative document.
| Element | Typical limit, percent |
|---|---|
| Manganese, minimum | 99.7 |
| Carbon, maximum | 0.04 |
| Sulfur, maximum | 0.05 |
| Phosphorus, maximum | 0.005 |
| Iron, maximum | 0.03 |
| Silicon, maximum | 0.01 |
Selenium is also commonly limited in EMM specifications because it is used as an additive in the electrolyte and must be controlled in the final metal.
Flake Form, Size and Packaging
EMM is supplied as irregular, bright flakes with a silvery metallic appearance. Flake dimensions vary by producer and specification, with typical commercial flakes ranging from about 10 to 80 millimeters across and a few millimeters thick. The material is commonly packed in 250 kilogram steel drums or one-metric-ton jumbo bags lined with plastic, and the drums are kept dry during transport because the clean metallic surface can oxidize in humid conditions.
Applications of EMM 99.7
Steelmaking: manganese is added to control sulfur and to strengthen steel; EMM raises manganese content without the carbon and phosphorus that ferroalloys bring.
Aluminum alloys: manganese improves the strength and corrosion resistance of aluminum-manganese alloys.
Copper and special alloys: manganese is alloyed with copper for damping and strength in manganese-copper alloys.
Battery materials: high-purity manganese is a raw material for electrolytic manganese dioxide used in alkaline and lithium batteries.
Welding and chemicals: manganese additions in welding consumables and in chemical manganese products.
Quality Checks When Receiving EMM
Buyers should check the appearance of the flakes, which should be bright and free of heavy oxidation, and confirm the packing weight. The certificate of analysis should be compared with the contract limits, and for critical applications a sample should be analyzed by an independent laboratory. Moisture content and the presence of foreign material should also be checked, because both affect the real manganese content delivered.
FAQ
Q1: What is the difference between electrolytic manganese and ferromanganese?
Electrolytic manganese metal is pure manganese produced by electrolysis, with 99.7 percent manganese or more. Ferromanganese is a furnace-produced alloy that contains carbon, iron and other elements along with manganese.
Q2: Is EMM 99.7 suitable for battery cathode materials?
EMM is an important raw material for producing electrolytic manganese dioxide and manganese chemicals used in batteries. The purity requirements depend on the cathode chemistry, and some applications call for further refining of the 99.7 grade.
Q3: How is EMM packed for export?
The common packing is 250 kilogram steel drums or one-metric-ton jumbo bags with a plastic lining. Moisture protection matters because the bright flake surface can oxidize in humid conditions.
Q4: Does EMM oxidize during storage?
Yes, the surface can oxidize when stored in humid air, which shows as a dull or dark film. Keeping the drums sealed and storing them in a dry warehouse limits this effect.
Q5: How can I verify the manganese content of a shipment?
Compare the certificate of analysis with the contract limits and, for critical lots, send a sample to an independent laboratory for wet-chemical or spectrometric analysis.