Abstract: Pyrolysis is one of the prospective processes that can be utilized to obtain high value chemicals and energy from coal and biomass. Coal-biomass co-pyrolysis presents a green, low-risk, cheap, sustainable, renewable energy source with low carbon emissions. Co-pyrolysis offers the highest yield of liquid fuels and gas compared to the individual feedstocks. It has been illustrated that the production yields experimentally usually exceed the calculated and this can be explained by the...
Abstract: The batch grinding equation and the Attainable region technique tools were used in evaluating data obtained from the breakage of quartz ore in a laboratory batch ball mill. Using the same milling conditions and grinding equipment, test results were evaluated through the breakage distributions of different size fractions. Results prove that mixing different grinding media increases volume of grinding zones and that translates to an improvement in grinding kinetics and amount of requ...
Abstract: This study investigated the application of the attainable region optimization technique to establish the optimum hybrid hydrometallurgical and pyro-metallurgical process conditions required to treat the electric arc furnace dust. The analysis of the results obtained showed that a combination of an agitation speed of 800 rpm, sodium hydroxide concentration of 8.0 mol/L and a leaching temperature of 80 °C were the optimum conditions for the hydrometallurgical process, while a ...
Abstract: In waste containment, it has become imperative that regimes of soil, surface and groundwater reserves are duly protected from contamination from leachate generation and migration in landfills. However, in developing countries such as South Africa, the construction of engineered facilities may be costly and the prevention of contaminants may become significantly reliant on the geology of the waste disposal site. More so, membranes forming part of geocomposite systems for waste conta...
Abstract: There are a number of factors that affect the output of the Fischer Tropsch process, change in the process parameters like catalyst used, residence time, temperature, pressure, particle size, bed height, flowrate and even the type of reactor used. A small manipulation of the parameters is enough to change completely the conversion, selectivity; therefore, these parameters have to be monitored. This paper presents the effect of the operation parameters on the Fischer Tropsch synthes...
Abstract: The interstitial filling, grinding media and feed particle size are vital parameters to be considered during ball mill operation. Experiments were conducted to ascertain whether there are possible interactions between the three variables and the fineness of the required product. The data obtained was analysed using the Attainable Region (AR) optimization method which is a model-free and equipment-independent tool. Experimental results indicate that there is a need to adjust or corr...
Abstract: Currently the majority of the world’s steel is produced through either one of the two main routes; the integrated Blast Furnace – Basic Oxygen Furnace (BF – BOF) route or the Direct Reduced Iron - Electric Arc Furnace (DRI - EAF) route. In the former, the blast furnace uses iron ore, scrap metal, coke and pulverized coal as raw materials to produce hot metal for conversion in the BOF. Although it is still the prevalent process, blast furnace hot metal production has declined ...
Abstract: In this study, the effects of reduction ration on different mineral ores was investigated when using common size reduction equipment’s and also factors affecting the working efficiency during crushing. A laboratory model of a unified crushing operation was used as an estimate to account for performance at industrial level, how energy consumption in a treatment plant can be minimized. Prediction on breakage behavior and fracture energy was estimated for common crushers how chemica...
Abstract: Biogas has been exploited as one of the alternative sources of renewable energy having the potential to replace fossil fuels. It contains impurities when raw, as it consists of 50e70% methane (CH4), 30e50% carbon dioxide (CO2) and trace gases such as hydrogen sulfide (H2S). Chemical absorption is often a preferred purification technique in industrial applications because it has high efficiencies, removes H2S completely, operates at low pressures, and has higher reaction rates. The ...
Abstract: amibia Custom Smelters (NCS) process a range of copper concentrates in their three furnaces, namely; top submerged lance, copper converter and reverberatory furnaces, in order to produce mattes and fayalitic slags. The copper content of the slags range between 0.8 to 5 wt. % and this is considered too high for disposal to the environment. Currently, the slags are sent to a milling and flotation plant for liberation and recovery of residual copper. The copper recoveries realized in ...
Abstract: Crop farming in Botswana is very modest and of high risk compared to its neighboring countries because of significant dependency on reduced and unreliable rainfall and as a result of soils with poor water holding capacity and low cation exchange capacity. For this reason, only about two thirds of the available arable land are planted and of the planted land only about half is harvested, which translates into only one third of productive arable land. This study examines how addition...
Abstract: The removal of sulphates from acid rock drainage (ARD) using basic oxygen furnace (BOF) slag was investigated. The results indicated that sulphates removal using BOF- slag increased with temperature increase (25-45oC), time (0-24 h) and solid loading (2-12 g BOF-slag/50 ml ARD). The maximum sulphate removal was 65% when 12 g BOF-slag/100 ml ARD was used at 45oC and 24 h residence time. Adsorption followed the Langmuir isotherm with maximum adsorption capacities at 25, 35 and 45oC o...
Abstract: The effect of ZrB2-Si3N4 particle reinforcement on the tribological behavior and microstructure of AA8011 alloy has been studied. ZrB2-Si3N4 particles were varied from 0 wt% to 20 wt% with an interval of 5 wt%. Dry sliding pin-on-disc tests at a room temperature condition were conducted to investigate the wear performances of the aluminium alloy/ ZrB2-Si3N4 composites. The tests were conducted at varying loads, from 20 to 40 N. The results depicted that the wear rates of th...
Abstract: The shovel-truck system is commonly used in open-pit mining operations. Truck haulage cost constitutes about 26% of open-pit mining costs as the trucks are mostly powered by diesel whose cost is escalating annually. Therefore, reducing fuel consumption could lead to a significant decrease in overall mining costs. Various methods have been proposed to improve fuel efficiency in open-pit mines. Case-based reasoning (CBR) can be used to estimate fuel consumption by haulage trucks. In ...
Abstract: Improving Available Transfer Capability is an important issue in the deregulated power systems. The Available Transfer Capability of a transmission network is the transfer capabilities of a transmission network for the transfer of power for further commercial activity, over and above already committed usage. It is a proven fact that Flexible Alternating Current Transmission System technology can control voltage magnitude, phase angle, and circuit reactance. Therefore, it is importa...