ASH FUSION TEMPERATURES UNDER OXIDIZING CONDITIONS

The ash fusion temperatures (AFTs) of 70 ashes (obtained from blends o f 7 North American source coals of varying rank) have been determined under oxidizing atmospheres in accordance with ASTM method D 1857. The se oxidizing AFTs have been compared with the corresponding AFTs obtai ned under reducing conditions. The temperature spreads, [AFT(OXIDIZING ) - AFT(REDUCING)], have been found to vary with ash composition, from -16.5-degrees-F (-9 K) to +425-degrees-F (+236 K). A procedure is des cribed for the development of regression equations to estimate each of the oxidizing AFTs, based upon ash compositional data. The best regre ssions provide AFT estimates with root mean square errors of 33-36-deg rees-F (18-20 K) (n = 67).