Potential Utilization of coal along Mbalawala River: Assessment of Coal Quality and Washability Characteristics

Abstract

Tanzania is blessed with large coal resources which can be categorized as lignite, sub-bituminous to bituminous. The current use of coal in Tanzania is as source of heating utility particularly in cement companies etc. However, there is a broad use of Tanzania coal particularly in the production of metallurgical coke for ironmaking in a blast furnace that can make huge impact to iron industry. In this work, the coal samples along Mbalawala River were investigated to determine size by size characteristics of the coal seams, in terms of distribution of ash content, volatile matter, calorific values, moisture and total sulphur. Washability data were generated to assess and compare the cleanability of the coals under investigation. The proximate analysis data shows that the ash contents of channel samples is 10.09 wt %. In addition, the ash content increase with the decrease of grain size while calorific value increase with increase in grain size this means calorific values are generally higher for the Mbalawala coal sample, and sulphur values are higher in the finer fraction (1.08 wt %). Volatile matter is evenly distributed in all size fractions. The results from the different channel samples display different Washability characteristics. The minimum ash values obtained is < 8 wt % ash and can be obtained at density < 1.60 with better cleaned coal. Therefore, this study recommends that the coal along Mbalawala River can be converted for further use such as other industrial and domestic purposes particularly metallurgical coke.