Effect of the Heat Treatment Temperature on the Compressive Strength of Coal Powder Compacts

This study considered the effect of the heat treatment temperature on the compressive strength of coal powder compacts affected by density, porosity, and crystallinity. Coal powder compacts were made by pressing of milled coal powder and were heat treated at 200, 400, 600, 800, and $1000^\circC$. The density and porosity of the heat treated specimens at each temperature were measured using the Archimedes method and changes in crystallinity were analyzed using Raman spectroscopy. Increases in compressive strength at $600^\circC$ or higher temperatures were proportionally related to increases in the density and the degree of crystallinity.