Abstract:

In this study, the effects of the middlings coal particle size on the liberation by crushing of Tunlan coal preparation plant was investigated through screening analysis and the sink–?oat test. The screening analysis and the sink–?oat test of the sample were carried out with the standard sieve mesh of 25 mm, 13 mm, 6 mm, 3 mm and the density grades of zinc chloride solution was 1.45kg/L,1.60kg/L and1.80kg/L respectively. The products with a density of 1.45-1.60 kg/L in each size fraction were selected and crushed to 3 mm. The sink–float tests were carried out with the -3mm materials and the ash content, volatile matter, caking property, sulfur and reflectivity of the products with a density of <1.45 kg/L were determined. The results show that the larger the original size fraction, the higher the yield of the cleaned coal, but the difference of ash content was not obvious. The results indicated that volatile matter, caking property, sulfur and reflectivity were unchanged with the particle size through liberation by crushing.

Key words: Coking middlings, liberation, volatile matter, caking property