Hyper-coal as Binder for Coking:—Macroscopic Caking Property, Microstructure Basis and Extraction Temperature Optimization Index

Abstract

ABSTRACT It is an effective way to utilize low-rank coal to obtain Hyper-coal by thermal extraction. Taking Shanxi lignite as raw material, the Hyper-coal was obtained by extraction at several temperatures. The basis of Hyper-coal as an excellent upgrading binder for coking was comprehensively studied from two aspects of macrocohesion index and microstructure. The experimental results show that the content of ash and sulfur in the Hyper-coal is low, and the content of light components is increasing with the increase of extraction temperature. The thermoplasticity of hyper-coal is generally high, the fluidity of colloid formed by pyrolysis is higher than that of conventional coking coal, and the bonding ability also reaches the level of fat coal. The source of high thermoplasticity of hyper-coal mainly depends on its microstructure, such as high aliphatic hydrocarbon content and wide thin compact carbon network structure. The optimum extraction temperature was 380°C. Generally speaking, Hyper-coal can be used as an excellent binder for coking.