Determination of the acid distribution and total acidity of low-rank coals and coal-derived materials by an improved barium exchange technique

The Schafer technique for the determination of acid distribution and total acidity of low-rank coals has been modified and improved to make the determinations quicker and cheaper without loss of accuracy. The acidity determinations have been extended to hydrophobic coal-derived materials by the addition of a trace of methanol (<0.3%, v/v) to the exchange medium.