Abstract
Using kerosene, crude tar and its fractions as reagents, the author carried out floatation of some coals and examined the influence of the addition of reagents upon the wettability of coals.The results were summarized as follows: -Tagawa and Heiwa coals were relatively high in the yield of cleaned coal, whilst Oani and Nakoso low.The yield increased with the decrease of ash content of raw coal, but the rate of de-ashing decrased.As the reagents, cresol, creosote oil and kerosene were suitable and the degree of de-ashing could be estimated by two curves which were obtained by changing the amount of addition of reagent.The wettability of coal was increased by both the addition of reagent and the elevation of temperature, as shown by the decrease of contact-angle, and also it was relatively proportional to ash content.Theteepol had superior effect in lowering contact-angle, as compared with the Rikaren, therefore it was considered to be more suitable as dustrestrainer.Besides above, it was recognized that the velodity of electrophoresis of coal was inversely proportional to ash content in the case of Sakito coal.
