Abstract
The department of mineral resources has seen a need for South African coal researchers and metallurgists to conduct research for cleaner coal processing and energy production, and thus created intervention strategies for the optimal beneficiation of the coal. The Geoscience conducted the first coordinated exploration programme in the springbok area between 1952 and 1972. A total of 27 boreholes (BHs) where drilled in the northern stern portion of the coalfield.
Five boreholes were drilled in the SFC (BH1 to BH5); BH5 had two coal zones, an upper coal zone (UCZ) and a lower coal zone coal (LCZ), but the focus on this study was on borehole two and borehole one. The samples from borehole two were subjected to combustion and from borehole one was subjected to alkaline leaching for the recovery of uranium. The selected coal samples named 1426, 1427, 1428 and 1429 were characterised for proximate and calorific value while both raw samples and combusted were analysed using successively X-ray diffraction, X-ray fluorescence, FTIR and SEM incorporated with EDS. Results obtained showed that the calorific value (CV) ranged from13.4 MJ/Kg to a maximum 22.4 MJ/Kg, with 1427 having the highest CV (22.4 MJ/Kg) and 1428 having the lowest CV (13.4 MJ/Kg). Inherent moisture, volatile matter, ash content and fixed carbon of 1427 after proximate analysis were 2.4, 29, 32.1 and 44.1 wt% respectively. The coal samples labelled 1436, 1437, 1439 and 1440 were selected for alkaline leaching. Results obtained showed that uranium (Ur) was successfully leached from coal samples into solution, where all samples registered high uranium recoveries when leached at high temperature (65℃,85℃ and 105℃), pH (10, 10.5, and 11), and longer time (24, 48, and 96hours). Results obtained from combustions showed that during combustion only small quantities of uranium were released to the atmosphere, therefore it will not be necessary to leach before combustion. The parts per billion (ppb) differences in Ur content varied from 1 ppb registered by sample 1428 to 21 ppb registered by sample 1426, when combusted at 800°C and the ppb difference in Ur content varied from 2 ppb registered by sample 1427 and 1428 to 13 ppb registered by sample 1429, when combusted at 900°C.
M.Tech. (Extraction Metallurgy)