Recovery of combustible matter from waste fine Chinese coals by a waste vegetable oil agglomerating process and its combustion characteristics

Abstract

Coal production increases continuously due to the development of mechanization in coal mining and demand in its related fields of application worldwide. Especially, coal production in China is increasing and a large amount of waste fine coals (<0.5 mm) which are difficult to be cleaned. Waste fine coals usually contain large amounts of ash contents and inorganic sulfur contents due to the mechanical coal mining of low grade coals. Therefore, waste fine coals are unavailable as energy resources, spontaneous combustion leading in turn to air pollution because of their coal content and small size which increases the surface area liable to be wet and oxidized, and occupation of disposal land which is also lead soil and water contamination. In this study, a waste vegetable oil agglomerating process was approached for coal combustible matter recovery from Chongqing Nantong waste fine coals in China. The oil agglomerating process had usually been developed by mineral oil (such as kerosene) of exhaustible resource. Therefore, in this study, simulated waste vegetable oils are selected as oil agglutinative agents because the waste vegetable oils which are recycled, renewable, and less polluting energy resources from the point of view of effective utilization of waste coal and on the cost front. However, waste vegetable oils have the possibility of influence on the coal cleaning efficiency, because the waste vegetable oils may be changed in the surface property and viscosity by different kinds of vegetable oils and chemical structure with the usage environment. Therefore, in the study, cleaning coal T. Maezono & D. Niida