Mesa Minerals Limited
Electrolytic Manganese Metal

The Mesa sulfur dioxide leach process offers a producer of high purity electrolytic manganese metal (EMM), who wishes to use manganese oxide ore as the plant feedstock, all the same benefits that an EMD producer can derive, as are outlined at some length under the electrolytic manganese dioxide (EMD) page of this website. (Such is the similarity of the electrolyte specifications for these two production processes that it is reasonable to visualise one single electrolyte generation and purification circuit feeding electrolyte to both an EMD cellhouse and an EMM cellhouse, with only minor adjustments to the two feeds after purification has taken place.)

The advantages of the Mesa sulfur dioxide leach process relative to a conventional manganese oxide ore roasting process include:

  • an improvement in metal purity from the more common 99.5% or 99.7% standards to the less common 99.8% standard making the output of the plant more attractive to industries requiring high purity (eg, in the electronics industry where EMM is used as feedstock for the production of ferrites);
  • a very significant reduction in ore acquististion costs;
  • a 50% reduction in energy consumed;
  • the total elimination of carbon dioxide emissions;
  • the creation of a second fertilizer product from the plant tailings (ie, a cost of production transformed into a valuable revenue);
  • the ability to eliminate virtually all particulate and metal ion emissions; and
  • the elimination of hydrogen sulfide gas from the cell house improving occupational health and safety conditions.

In places where there is an abundance of manganese carbonate ores, such as in southern China, EMM and EMD tend to be made by dissolving the carbonate ore in sulfuric acid, rather than roast reduction followed by acid dissolution, as is the case for manganese oxide ores. These carbonate ores tend to be low grade and, where an alternative low grade manganese oxide ore is also available, producers could benefit by adopting the Mesa process. In doing this, they would be able to convert all plant tailings to a valuable fertilizer product. This can be a very significant advantage, as when manganese electrolytic products are produced from manganese carbonate ores, the tailings produced can be up to 5 times the volume of tailings produced when manganese oxide ores are used resulting in very significant land use and long term impoundment costs.

The combination of a second revenue stream, lower impoundment costs and vastly improved plant environmental performance makes the adoption of the Mesa leach approach inevitable where low grade oxide ores are also available. Even for existing plants, the low capital costs involved with retrofitting a Mesa sulfur dioxide leach circuit and the increased plant profits would mean a very quick payback period for the investment. Additionally, the manganese carbonate ores not used would then be available for manganese alloy production to meet the demands of the steel industry.

Click here for more information onĀ Mesa Minerals Products.