石炭の単体分離に影響を与える因子

Abstract

The effects of mineral content, and mineral distribution in coal, and pulverizing method on characteristics of mineral liberation were investigated in order to develop an efficient de-ashing method for coal. It is found that the effect of mineral content on the characteristics of mineral liberation is significant at a mineral content lower than 10wt%, while it is weak at a mineral content exceeding 10wt%. When the particle size of pulverized coal was 120μm, the minerals in coal were more easily liberated than the mineral particles larger than 120μm. In addition, the mineral liberation during the pulverization of coal containing granular minerals, i.e., locally-distributed minerals, into finer particles was higher than in the coal with linear minerals, i.e., linearly-distributed minerals. A high degree of mineral liberation was attained when the pulverizing methods based on impact force (ball mill and hammer mill) were used for the coals that contained a large amount of granular minerals. On the other hand, for coals that contained linear minerals, it was effective to use the pulverizing method based on compressive force, such as a Roll mill and HGI mill. Consequently it was found that the selection of a suitable pulverizing method depending on the mineral distribution in coal was important for achieving efficient mineral liberation.