Upgrading the coking properties of Lamza coal by adding bitumen

Proximate analysis, free swelling index, Gieseler plastometry and Ruhr dilatometry characteristics of the weakly coming Nigeria Lamza and Australian coals were determined. Various proportions of washed Ondo bitumen were added as coking additives to improve the plastic properties of the coals. Proximate analysis of Lamza samples gave average moisture, ash, volatile matter, sulphur and fixed carbon values of 1.86%, 11.17%, 43.50%, 0.81% and 56.50%, respectively; while that of Australian coal gave 1.03%, 5.65%, 30.52%. 0.22% and 67.80%, respectively. Gieseler plastometry gave zero fluidity for Lamza samples and 2,100 dial division per minute (ddpm) for Australian sample. For Ruhr dilatation, Lamza samples contracted only by about 13% while Australian coal contracted by -14% with a dilatation of -8%. On adding 15% bitumen, the Lamza coal was upgraded from ISO No 811 to ISO No 812 with a Gieseler fluidity of 223 ddpm, absolute dilatation of 18% and G- value of 0.971. Also, an addition of 10% bitumen improved Australian coal from the ISO No 522 to ISO No 523, with an absolute dilatation of 36% and a G-value of 1.024. An addition of 15% bitumen to Australian coal drastically raised its Gieseler fluidity to 19,100ddpm. The G values obtained are characteristic of coals for coke making.