A Comparative Study Of Microwave Heating Characteristics On Manganese Carbonate Ore Fines Containing Coal And Manganese Oxide Ore Fines Containing Coal

In our country, the types of manganese ore are mostly manganese carbonate ore and manganese oxide ore. Although the reserves are very large, above the 90% of them are the granule and low-grade ore that is difficult to beneficiate and refine, and they have high-content phosphorus, iron, and silicon. Above the 90% of the mined manganese ores are used for the production of ferromanganese and manganese metal. With the rapid development of the Iron and Steel Industry, especially the stainless steel with manganese instead of nickel and the stainless steel of Cr-Mn that saving nickel, the demand of ferromanganese and electrolyzed manganese metal increases rapidly. As the ores grade is low, a part of imported high-grade manganese ores must be used with domestic low-grade manganese ores to produce the ferromanganese, which makes the import dependence of manganese ores raise year by year. Moreover, a mass of powdery manganese ores by ores processing and lump ores haulage can not be added directly into the oven before the artificial conglomeration.Microwave is a new type of heating energy, which can quickly and selectively heat powdery materials, avoiding no uniform heat transfer of powdery materials by traditional heating methods. Manganese carbonate ore fines, manganese oxide ore fines, and anthracite fines all have good microwave absorption properties. The reduction of (low-grade) manganese ore fines containing coal by microwave heating, which not affected by the traditional heat transfer law, can achieve temperature rising quickly, and maximize the self-reduction properties of the low-grade manganese ore fines containing coal at high temperature, to obtain the powdery sponge ferromangnanese with a certain degree of metallization.Microwave heating transfers the microwave energy to heat energy by the dielectric loss of the powdery metallurgy materials and magnetic loss of metallide formed in the reduction precess in microwave field, to achieve the quick temperature rising and reduction of the materials. Therefore, in the course of reduction of the manganese carbonate ore fines containing coal and manganese oxide ore fines containing coal by microwave heating, the study of the temperature-rising characteristics and electromagnetic performances of the materials has a significant meaning for analyzing the dynamics of their reduction reaction in microwave field.In the paper, a comparative study of the temperature-rising characteristics and electromagnetic performances on the manganese carbonate ore fines containing coal and manganese oxide ore fines containing coal by microwave heating is made. The results show that, they all have good temperature rising characteristics, and the latter, with faster temperature-rising rate and shorter heating time, is better. They all belong to the matter of dielectric loss, and the course of temperature-rising is to transfer microwave energy mainly by the dielectric loss. The dielectric properties of manganese carbonate ore fines containing coal are markedly weaker than that of manganese oxide ore fines containing coal, but the magnetic properties of them have little difference. The differences of their temperature rising characteristics depend largely on the differences of dielectrical property. In the course of microwave heating, the temperature-rising characteristics and electromagnetic performances are mainly affected by the following factors: composition and structure of materials, containing coal ratio of materials, heating temperature, etc. With the increasing of the containing coal ratio, the temperature-rising characteristics and electromagnetic performances of materials all increase; while with the rising of heating temperature, the temperature-rising characteristics and electromagnetic performances of materials all decrease at some degree.