鉱物処理

[2201-09-05] Effects of freeze drying on physico-chemical properties of Loy Yang lignite

^○Xiang chun Liu¹, Tsuyosh HIRAJIMA¹, Moriyasu NONAKA¹, SASAKI SASAKI¹ (1. Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University)

司会: 綱澤有輝（産業技術総合研究所）

Keywords:freeze drying, residual water content, water re-adsorption, kerosene

Loy Yang lignite was dewatered using freeze drying (FD). Residual water content, sorption behavior, and pore size distributions were studied. Moreover, coating different amounts of kerosene using adsorption or direct mixing methods to reduce water re-adsorption was also investigated. The results showed that FD dewatering can be divided into three steps, i.e., a fast dewatering step (∼2 h), a reduced drying rate step (2∼3 h), and an apparently falling rate step (> 3 h). Moisture holding capacity (MHC) of the FD treated samples was lower than that of raw lignite. This is because of effects of water–lignite bond strength and diffusion adsorption or desorption force. Moreover, adding kerosene using adsorption or direct mixing methods can both decrease MHC since kerosene is coated on the surface and in the pores of the lignite, which forbid water re-adsorption. Adsorption method consumed less kerosene than direct mixing method.