Mian Factors controlling concentration of trace element in coal

Based on the genetic analysis of trace elements in the coal of Yanzhou mining district and the summary of previous conclusions, the concentration processes of trace elements are divided into three stages, i.e.primary, secondary and hysterogenic stages.The main factors, which impact on concentration and migration of trace elements, are analyzed.The results indicated that during the coal formation, which began from plants growing to peat swamp and to types of coal rank, there are many factors influencing migration and concentration of trace elements.The factors mainly include plant types, chemical conditions, climate conditions, seawater encroachment, magma hydrothermalism during coalification, and matter exchange between coal and rocks of roof and floor.Therefore, the generation and concentration of trace elements in coals are controlled by many geological factors during every coalification stages.