Determination of the mineral distribution in pulverized coal using densitometry and laser particle sizing

Coal particle size and mineral matter content have important effects on coal combustion. The mineral content of five Chinese coals was determined by a method combining densitometry and particle-size analysis. The finer particles of pulverized samples were found to contain more mineral content. Rank also had a significant influence on the particle-size ash-content distribution of pulverized coal particles. The sharpest size-ash distribution was found in pulverized anthracite samples; a broader distribution was found with bituminous coal samples, while a uniform distribution was observed in pulverized lignite samples. Ash in higher ash anthracite or lower ash bituminous coal is more evenly distributed. It is a combined effect of size distribution, yield, and proximate analysis of their density separation fractions. Mineral matter tends to distribute more evenly in finer pulverized coals. This results from a relative increase of the low-density fraction in the finer particles.