Study on maceral characteristics and separation of low-rank coal

Abstract

ABSTRACT This paper studies the characteristics of Shenhua low-rank coal, including industrial analysis, element analysis, density composition, particle-size composition, maceral characteristics and enhanced gravity. The separation characteristics of Shenhua low-rank coal maceral were examined by manual enrichment, screening enrichment and centrifugal heavy-liquid separation. After manual enrichment, vitrinite content was 31.06% higher than vitrinite content in raw coal, and inertinite content was increased by 13.50% compared with raw coal. The screening results show that vitrinite is easily broken into small pieces to be enriched in coarser particle size (0.125–0.074 mm), and inertinite is easily enriched in fine particle size (−0.045 mm); Centrifugal heavy-liquid separation showed that product in range of −1.30 g/cm3 was taken as pure vitrinite and product in range of 1.36–1.40 g/cm3 was regarded as purer inertinite. Finally, using rod mill products as feed material of enhanced gravity separation to study effect of feed speed, rotation frequency and recoil water on vitrinite recovery, vitrinite recovery of 71.81% and vitrinite content of 68.72% are obtained respectively under the optimal conditions of 30 Hz rotation frequency, 0.03 MPa recoil water pressure and 15 ml/s feed speed.