Remediation of oil-contaminated sand by coal agglomeration using ball milling.

The mechanical shear force provided by a less energy intensive device (usually operating at 20-200 rpm), a ball mill, was used toperform coal agglomeration and its effects on remediation of a model fuel oil-contaminated sand were evaluated. Important process parameters such as the amount of coal added, milling time, milling speed and the size of milling elements are discussed. The results suggested that highly hydrophobic oil-coal agglomerates, formed by adding suitable amounts of coal into the oil-contaminated sand, could be mechanically liberated from cleaned sand during ball milling and recovered as a surface coating on the steel balls.

Preparation of coal slurry with organic solvents.

In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal-organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal-organic solvent slurries usually showed higher viscosities compared to coal-water slurry.

Preparation of coal slurry with 2-propanol.

This study explored the feasibility of using waste organic solvents as substitutes for water to prepare coal slurries. The rheological properties of coal-2-propanol slurries were examined and compared with that of coal-water slurry (CWS). The good compatibility between coal particles and 2-propanol resulted in stable particle suspension in slurry which usually exhibit Newtonian behaviour.