The magnetic separation process of manganese ore can be applied to separate high phosphate ore, high-silicon ore and low bixbyite ore.
Ore washing is to separate ore from mud by hydraulic flushing or additional mechanical scrubbing. Common-used equipment includes washing screen, cylinder washer and trough washer.
Ore washing operations are often accompanied by screening, such as washing directly with water on the vibrating screen, or sending the washed ores to the vibrating screen. Screening can be used as an independent operation to separate products of different sizes and grades for different purposes.
Gravity separation is only used for separating manganese ores with simple structure and coarse particle size, especially for manganese oxide ores with high density. The common methods are heavy medium beneficiation, jigging beneficiation and shaking table beneficiation. Generally speaking, the processing of manganese oxide ores requires to crush the ore to be smaller than 10mm size, then divides the ores into groups, the coarse ores are processed by jiggers and the fine ores are processed by shaking tables.
Manganese minerals belong to weak magnetic minerals. They can be recovered in strong magnetic separators with magnetic intensity Ho=800-1600 kA/m
Because of simple operation, easy control and strong adaptability, magnetic separation can be used for the separation of various manganese ores. It has been dominant in the mineral processing of manganese ores in recent years. Various new types of coarse, medium and fine-grained high-intensity magnetic separators have been developed successively. At present, the most common application of manganese ore in China is medium-sized high-intensity magnetic separator. Coarse and fine-grained high-intensity magnetic separators are also gradually applied. The fine-grained high-intensity magnetic separator is still in the experimental stage.
At present, the newly built and rebuilt heavy-magnetic separation plants in China include Liancheng, Fujian, Longtou, Jingxi and Xialei. For example, Liancheng Gravity-Magnetic Separation Plant mainly deals with leaching manganese oxide ores, and uses AM-30 jig to treat 30-3mm washing ores. High-quality manganese concentrate containing more than 40% manganese can be obtained. After manual separation, it can be used as raw material for battery manganese powder. The grade of manganese concentrate should be increased by 24%-25% to 36%-40% when the jigging tailings and the washing diameter less than 3mm are milled to less than 1 m by high intensity magnetic separator.
At present, only Zunyi manganese ores processing project uses strong Magnetic-flotation processing. The ore is a low manganese, low phosphorus and high iron manganese ore dominated by manganese carbonate.
According to the industrial test, the grinding process adopts rod mill-ball mill stage grinding, the grinder is 2,100 mm x 3,000 mm wet grinder. Strong magnetic separation uses SHP-2000 strong magnetic separator, flotation machine mainly uses CHF inflatable flotation cell. The successful test of strong magnetic-flotation process and its application in production indicate that the deep separation of manganese ore in China has made a great step forward.
The pyrometallurgical enrichment of manganese ores is a separation method for treating refractory low-grade manganese ores with high phosphorus and high iron. It is generally called manganese-rich slag method. Its essence is a high temperature separation method for selective separation of manganese, phosphorus and iron by controlling the reduction temperature of manganese, phosphorus and iron in blast furnace or furnace.
There are many chemical beneficiations of manganese, and a lot of research work has been done in our country. Among them, there are many experiments, and the most promising ones are dithionate method, black manganese ore method and bacterial leaching manganese method. At present, it has not been put into industrial production.