A novel technology for the deash of fine coal by an active pulsing air separation system

t is essential to remove gangue minerals associated with coal as they are harmful, and easy to cause environmental problems if the utilization process is not sustainable. To achieve this, various separation technologies including dry separation methods have been developed. As two-thirds of recoverable coal in China is reserved in water-lack areas, the development and research into dry separation methods has attracted more and more interests and also becomes the focus of the presented work. Besides a focusing on beneficiation of -6+3 mm and -3+1 mm coal particles, this paper aimed to propose a novel separation technology, namely the active pulsing air separation system (APASS). The response surface methodology (RSM) was used to investigate the effects of operational parameters, including airflow rate, pulsing frequency and feed rate, on separation results of two narrowly sized coal samples. Experimental results indicated that separation densities of two coals were similar, and the coarse one showed a relatively higher separation precision. Due to the high yield of particles around separation density and collision among particles, separation results were not good enough as the deash degree was only about 10%. To improve the product quality, the primary and secondary separation flowsheet of the active pulsing air separation system is proposed.