Liberation characterization of minerals and macerals in coal by using MLA

FU Yanhong; LI Zhen; ZHOU Anning; ZHU Ziqi; YANG Chao; LIU Lijun; YU Wei; QU Jinzhou

Abstract：To study the liberation characteristics of minerals and macerals in coal,we selected coal samples from Yangchangwan of Ningdong,Ningxia,and investigated the characteristics of coal and mineral liberation,crack distribution and maceral liberation with rod grinding and ball grinding by using mineral liberation analysis (MLA).The results manifest that the response of particle size distribution to ball grinding time is weaker than that to rod grinding time;the response of coal liberation to ball grinding is relatively stronger and the corresponding cumulative mass recovery of 100％ liberation (CMR100％) by 50 min ball grinding can reach up to 74.80％;the responses of kaolinite to both grinding methods are similar;the responses of quartz to rod grinding time and ball grinding pattern are stronger,and the corresponding CMR100％ of ball grinding can reach up to 34.48％;in terms of muscovite liberation,the selectivity of rod grinding is stronger than that of ball grinding;the responses of pyrite to ball grinding time and pattern are both stronger than those to rod grinding,and the corresponding CMR100％ of ball grinding can reach up to 40.12％.The liberation models of macerals are predicted as follows:random cracks are easier to be generated under the ball grinding effect,while phase boundary cracks,which are more useful for the liberation of macerals,are easier to be generated under the rod grinding squeezing action.