Electronic Theses and Dissertations (Masters)
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Item Flammability, corrosion resistance, and environmental friendliness of coal composites produced from various coal fines(University of the Witwatersrand, Johannesburg, 2024) Vatsha , Mhlawakhe; Bada, Samson O.The concept of recycling carbon-containing waste into secondary raw materials is highly promising for fostering a resource-efficient and circular economy, given the increasing scarcity of natural resources and growing population. The effectiveness of coal tar modified by air- blowing technique as a binder “pitch” for coal fines in the production of structural composites is highlighted in this study. In addition, the feasibility of commercial dimethylpolysiloxane as a binder for coal carbon composite production was assessed and compared to that produced using coal tar-pitch. The two coal fines (GG1 and GS) used in this study have an ash content of 84.02% and 62.27%, respectively, and can be classified as rock. Their fixed carbon content ranges between 5.44% and 16.27%, compared to coal tar (35.23%). The coal tar has a volatile matter content of 64.50%, and with the air-blowing pretreatment, the tar was converted to pitch with a low volatile matter content of 11.27%. A pitch with the highest fixed carbon content of 87.68% and total carbon content of 96.01% was produced. Various ASTM standard test methods were used in the investigation to characterise and evaluate samples, including mineral phases and functional groups in the raw and coal composites produced. The composites were fabricated using a circular mould with a diameter of 30 mm and a 40 mm square mould. In the study, it was found that composites with a low H/C atomic ratio had low water absorption. Additionally, composites with high volatile matter content had high water absorption. However, the sample with the highest water absorption (19%) was the GG1 50/50 coal tar pitch 400-composite, which falls within the range (0-25%) for building materials. The composites with an intense O-H group had high compressive and flexural strengths ranging from 106.58 to 344.71 MPa and 48.75 to 159.30 MPa, respectively. The flammability of all composites was low. The highest flammability mass ablation rate and linear ablation rate were found to be 0.008 g/sec and 0.00983 mm/sec, respectively. In terms of the corrosion rate, the GS 80%/20% dimethylpolysiloxane coal composite had the highest corrosion rate (0.081 μmpy), which is minimal compared to some commercial ceramic tiles. The composites' environmental friendliness was determined by leaching them at various pH levels. The test was conducted by comparing the concentration of heavy toxic elements in the solution to the leachable concentration threshold for waste management standards (NEM WA Act No. 59 of 2008). All composites were environmentally friendly, meeting the moderate risk leaching concentration threshold. The composites that were produced in this study from South iii African discard coal can be used in large quantities in the environment without any danger or hazards, as demonstrated. Based on this study's overall results, repurposing South African discard coal as carbon/ceramic composites for building materials could play a role in the country's Just Transition initiatives. In addition to waste reduction, this strategy could reduce operational emissions, improve circularity, and address associated environmental risks.Item Development and Application of activated carbons from Avocado waste: Resource recovery for sustainable applications(University of the Witwatersrand, Johannesburg, 2023) Mohale, Lehlohonolo; Mulopo, JeanThis research sought to produce activated carbons that could be used for hydrogen storage. The effect of hydrothermal pretreatment of the char, the effect of varying the activation ratio of KOH as the activation agent and the effect of activation temperature in producing these activated carbons were evaluated. Hydrothermal pretreatment of the char enhanced the properties of the resulting activated carbons. The best performing activated carbon was produced from the hydrochar pretreated at 200℃. It was observed that activation improved with increased activation agent concentration and activation temperature, to a point, and the best activated carbon was produced at 1:3 activation ratio and 800℃ activation temperature. This activated carbon had the highest total pore and micropore volumes of 1.45cm3/g and 1.16 cm3/g, respectively. The highest surface area of 2529.8m2/g was obtained, which is relatively higher than previously reported surface areas obtained from activated carbons created from coal or biomass. The porosity and the high surface area show well developed activated carbons that have desirable gas adsorption performance. The activated carbons had oxygen containing functional groups that aid in hydrogen sorption, the highest hydrogen sorption at 77K and 1 bar was 352 cm3/g, which supports the use of the produced activated carbons in the hydrogen economy. These activated carbons enable the circular economy. Well developed micropores were observed in the activated carbons produced through this work and their gravimetric capacity meets the DOE targets for hydrogen storage.Item Simulation of a Wet Flue Gas Desulphurization (WFGD) plant in support of continuous grid supply of electricity and compliance to SO2 emission limits(University of the Witwatersrand, Johannesburg, 2024) Lekhuleni , Tsholofelo Bernice; Mulopo, JeanThe wet flue gas desulphurization plant is susceptible to attrition and corrosion due to the corrosive nature of its operation. It is crucial to prevent plant downtime at any cost, as a plant failure in the WFGD could disrupt electricity supplies to the national grid. Plant failures can be avoided by using models to optimize plant operations and assure higher system performance. In this work, the Aspen simulation was used to forecast the following parameters for a wet flue gas desulphurization process: • Lowest limestone concentration or quality as absorber feed, • Highest volume of gas that can be treated, • Maximum sulphur content that could be treated in the absorber tower. Various reactions such as limestone dissolution, SO2 absorption and crystallization were simulated in Aspen. An equilibrium relation was established where the SO2/SO3 relationship in the absorber reaction could be used to predict the lowest concentration of limestone slurry and the highest volumetric flowrate that could be treated in the absorber. The pH drops in the absorber and the formation of gypsum (CaSO4) also supported the findings of the equilibrium relationship. The lowest limestone concentration limit is 16% compared to a design base of 31%. The maximum volumetric flowrate is in the range of 4,0-4.5 x 106 m3/h. The maximum sulphur content that could be treated is 1.6% S on a mass basis compared to a design base of 0.9%. However, the maximum sulphur was reduced to 1.41 % due to the limestone control dosing valve which can only supply 90000 kg/h instead of the maximum requirement of 94315 kg/h. The equilibrium relations, pH, and gypsum production can all be used to establish safe operating regimes for the WFGD plant.Item Physico-chemical properties and treatment of scale formation in dust scrubber discharge lines at a PGM Smelter in South Africa(University of the Witwatersrand, Johannesburg, 2024) Fungene, Thandiwe; Ndlovu, SehliseloSeveral technologies in the field of flue-gas desulphurization (FGD) have been created to address the issue of sulphur dioxide (SO2) emission from gas streams. Among these, wet scrubbing, particularly the use of lime/ limestone (Ca(OH)2/ CaCO3) scrubbing, stands out as the primary method for reducing SO2 emissions from power plants. These methods are simple and cost-effective, making them suitable for various industrial facilities that emit SO2, including refineries and smelters. In Ca(OH)2 or CaCO3 scrubbing systems, calcium (Ca) compounds are introduced in the form of slurries into the scrubber liquid. However, this process leads to the undesired creation of solid Ca salts. Consequently, the solubility of Ca salts in the slurry restricts the efficiency of wet scrubbing techniques containing Ca. If the ion concentration in the water exceeds the solubility limit of Ca salts like calcium sulphate (CaSO4), it can result in the development of supersaturated CaSO4, which may lead to scale accumulation or deposition in the scrubber. This scaling issue, in turn, requires frequent plant shutdowns to open and remove scale from pipelines. The aim of this research is to propose a process for the prevention of hard water scale or its removal in FGD systems, particularly scrubbers commonly utilized in PGM smelters. To accomplish this goal, analyses were conducted to both physically and chemically characterize the scale or deposit, as well as all the feed materials within and around the variable throat scrubber (VTS) system at a local PGM smelter. By leveraging the physical and chemical properties of these materials, this study explores the application of traditional chemical "water softening" techniques like ion exchange and precipitation, as well as an emerging physical method known as magnetic water treatment (MWT), to combat scale formation in scrubbers. The water samples obtained from the Sibanye-Stillwater scrubbing circuit were characterized by extremely high levels of Ca and magnesium (Mg) hardness (1000—8000 mg/L CaCO3) and high levels of total dissolved solids (TDS) (3000—9000 mg/L). Both a strong acid cation exchange resin (SAC) and weak acid cation exchange resin (WAC) were employed in the treatment process. The WAC resin, commonly used for high TDS solutions, displayed better removal of Ca and Mg compared to SAC, effectively bringing the total hardness levels down to 120—180 mg/L CaCO3. Chemical precipitation using a lime and soda ash pre-treatment step prior to cation exchange resulted in residual hardness levels of 0—120 mg/L as CaCO3. Physico-chemical properties and treatment of scale formation in dust-scrubber discharge lines at a PGM smelter in South Africa Thandiwe Fungene VI The use of MWT remains a topic of debate as a non-chemical option for water softening due to concerns about its scientific validity. This research aims to investigate the potential of a magnetic field to reduce hard water scaling. Several factors, including pH, dissolved oxygen (DO), electrical conductivity (EC), calcium ion concentration ([Ca2+]), and scaling potential, were compared between treated and untreated water. The treated water displayed notable changes in these factors. Most significantly, the precipitation in treated water indicated a shift from calcite to aragonite formation, essentially inhibiting the overall scaling potential. These findings are substantiated by a mechanistic theory based on a comprehensive review of successful applications in the existing literature. This study holds significance in questioning the sustainability of chemical-based water treatment methods and explores the feasibility of non-chemical alternatives.Item An Investigation into the Effect of Advanced Gravity Separation on Platinum Group Metals (PGM) Flotation Concentrates(University of the Witwatersrand, Johannesburg, 2024) Nair, Taurean Jevaldo; Sibanda, Vusumuzi“It's the gravity that shapes the large-scale structure of the universe, even though it is the weakest of four categories of forces” - Stephen Hawking Gravity concentration has been around since the dawn of mankind, and just as man has evolved so too has gravity concentration. The earliest records involved ancient cultures (Greeks, Romans, Mayans and Egyptians) using water to selectively separate precious metals from gangue. Gravity concentration has remained an integral part of many processes involving the recovery of native or alluvial precious metals and minerals which are amenable to this process. Developments in gravity concentration technology have led to the inception of advanced gravity separation devices. These advanced gravity separators can overcome the challenges associated with conventional gravity concentration as they are able to induce a high gravitational force that is capable of recovering fine and ultrafine heavy particles as well as particles with a complex mineralogy. Decreasing feed grades and falling metal prices are placing an exorbitant amount of pressure on the PGM industry. As a price-taker, the industry is at the mercy of the prevailing market conditions. This means that the only levers the industry can use are cost cutting or optimization of the process to produce more PGMs at a better quality from the current feed source. The premise of this research project is to essentially find a way to optimize the PGM beneficiation process by the use of gravity concentration. This research specifically targeted the high-grade flotation concentrate stream of a UG2 tailings plant to understand how effective advanced gravity concentration would be in recovering PGMs, upgrading the resulting concentrate as well as rejecting chromite and gangue. PGMs are associated with base-metal sulphides and are inherently complex. This complexity is further exacerbated by the fact that PGMs are in the fine to ultrafine particle size range which makes recovery of PGMs challenging. Gravity concentration is primarily a function of particle size, density and mineralogy. Separation of gangue and chromite from PGMs is another added complication as the gangue minerals are present in higher concentration than the PGMs, have a complex mineralogy and are also found in the fine and ultrafine particle sizes. Fire Assay/ICP- ii MS, XRF, XRD and SEM all confirmed the complexity of the ore being treated. This ‘entanglement of complexity’ makes processing these ores very challenging. A lab-scale Falcon gravity concentrator with an unfluidized (ultrafine) bowl was used in the main experimental work. The optimal parameters to run the gravity concentrator for PGMs was found to be a flow rate of 3 L/min, percent solids of 13.22% and a gravitational force of 300 G’s. These parameters were then applied to a multi-stage gravity concentration process. The feed to the gravity concentrator was found to have a grade of 131.02 g/t 4E PGM. The results indicated that a recovery of 48.90% and a final concentrate grade of 292.04 g/t 4E was achieved at a mass pull of 21.90%. The chromite in the final concentrate of the Falcon gravity concentrator was found to be 1.99% which did not exceed the maximum allowable chrome in concentrate of 3.00%. This proved that gravity concentration was indeed capable of recovering complex PGMs and rejecting chromite. The optimal parameters experiments indicated repeatability, and the assay results were validated by a statistical outlier test in the Minitab Software to ensure data integrity. The particle size analysis revealed that 97.07% of the feed to the Falcon was below 75μm and 66.29% below 25μm, thus confirming that the feed material was fine to ultrafine particles. The final gravity concentrate had a D90 of 42.24μm which was finer than the D90 for the feed, this demonstrates that fine and ultrafine heavy particles were more mineralized and recoverable by the Falcon. This analysis was further reinforced by the fractional analysis which confirmed that the majority of the PGMs were found in the fine to ultrafine fraction. The experiments were repeated using a fluidized bowl in the Falcon to see what the impact of fluidizing water would be. These experiments had lower overall recoveries and mass pulls than those done with an unfluidized bowl. The concentrate grade was, however, higher than the unfluidized bowl experiments possibly due to this bowl recovering PGMs in the coarser fraction. This research provides a steppingstone to understanding the effect of advanced gravity concentration on PGM flotation concentrates and indeed on PGMs in general as well as providing an alternative unique processing option for PGMs. Ultimately advanced gravity concentration has been shown to be an uncomplicated process that can be viable in the recovery of fine and ultrafine complex PGMs. It is environmentally friendly, has low capital and operational costs and has a relatively high efficiency.Item Characterizing flotation processes of Platreef PGM ores: The applicability of models based on the Weibull and γ rate constant distributions(University of the Witwatersrand, Johannesburg, 2024) Ngema, Sithandokuhle Fortune; Safari, Mehdi; Sibanda, VusumuziThis dissertation delves into a comprehensive examination of the flotation behaviour of Platreef Platinum Group Metal ores, with a specific focus on the applicability of two widely used distribution models, the Weibull and Gamma distributions. The primary objective of this study was to demonstrate the effectiveness of these models in characterizing the flotation response of the ore under varying grind sizes, ranging from 80% passing 150 μm down to 38 μm, and under varying collector dosages. In this research, a series of meticulous experiments that involved the collection of samples from Platreef PGM ore were conducted. These samples were characterized based on their mineralogical composition, and their flotation behaviour across specified particle size distributions and varying collector dosages. The gathered data were then subjected to analysis using the Weibull and Gamma models. This allowed the assessment of the flotation performance of the ore and the description of the intricate flotation sub-processes involved to be possible. The parameters for both the Weibull and Gamma distributions were determined through a rigorous statistical method known as regression. This method involved fitting the experimental data to the models and iteratively adjusting the model parameters until convergence to their most accurate estimates was achieved. The results from the research reveal that both the Weibull and Gamma models demonstrate a commendable ability to describe the flotation process of Platreef PGM ores. However, the study also highlights certain limitations of these models, especially when dealing with coarser grind sizes, where the Weibull model shows a slight decrease in effectiveness. The investigation also points to the significant impact of liberation and grinding time on the accuracy of these models. These findings underscore the importance of understanding the nuances of particle interactions and liberation at different grind sizes in floatation processes. Furthermore, the effect of varying collector dosages on the performance of the models was explored. It was observed that the accuracy of the models diminishes with longer residence times, particularly when collector dosages are changed. This sensitivity to longer residence times and grind characteristics underscores the need for a holistic approach to model development. Another intriguing aspect of the study was the relationship between collector dosage and grind characteristics. It became apparent that increasing collector dosage has a more v pronounced positive effect on recoveries for both coarser and finer grinds, while the intermediate grinds exhibit a less substantial improvement. This discovery challenges the convention of a near-linear relationship between collector dosage and recovery. In conclusion, the research provides valuable insights into the complexities of the flotation process for Platreef PGM ores and underscores the significance of selecting the most appropriate distribution models based on specific ore characteristics and grind sizes. The dissertation also highlights the need for a nuanced approach to process optimization, acknowledging the interplay of factors such as liberation, grind characteristics, and collector dosage. This understanding can be applied to enhance recovery rates and efficiency in flotation processes, offering valuable contributions to the field of mineral processing and chemical engineering. Findings of this work shed light on the intricate nature of chemical processes, emphasizing the importance of a holistic approach to model development and practical applications.Item Carbon nanotubes application for lithium-ion battery anodes(University of the Witwatersrand, Johannesburg, 2024) Mhlanga, Nqobile; Raphulu, Mpfunzeni; Sibanda, VusumuziThe most commonly used anode material for lithium-ion batteries (LIBs) is graphite, however it has some shortcomings such as having a low reversible capacity and low diffusion rate which produce low-power density batteries. Thus, the purpose of this study was to examine the application of carbon nanotubes (CNTs) as an alternative LIB anode material. A bimetallic iron-cobalt catalyst supported on calcium carbonate (Fe-Co/CaCO3) was used for the synthesis of CNTs and it was prepared using the wet impregnation method. X-ray diffraction (XRD) analysis of the catalyst showed that it was highly crystalline. The specific surface area (SSA) which was determined using Brunauer-Emmett-Teller (BET) was found to be 11.3 m2/g. CNTs were prepared using the chemical vapour deposition (CVD) method at various test parameters i.e. temperature (650°C,700°C,750°C and 800°C), hydrocarbon flow rate (90 mL/min and 120 mL/min) and carbon source (acetylene and ethylene). High-resolution transmission electron microscopy (HRTEM) results for samples synthesised at 650°C and 700°C using acetylene at a flow rate of 90 mL/min (650°C-A90 and 700°C-A90) showed that CNTs which were multiwalled carbon nanotubes (MWCNTs) in nature were produced. The formation of what appeared to be non-tubular carbon and carbon nanofibers was observed when the synthesis temperature was increased from 700°C to 800°C. The average outer diameter (OD) of the tubes ranged from 20 to 89 nm. At a higher acetylene flowrate (120 mL/min), the quality of CNTs seemed to deteriorate for synthesis temperatures above 650°C. The formation of non-tubular carbon-like nanofibers was observed at synthesis temperatures above 650°C. The average OD of the tubes ranged from 22 to 81 nm. XRD analysis of all samples synthesised using acetylene showed a similar pattern with the most intense peak being that of carbon and minor peaks being of iron. The samples also contained some broad peaks which suggested that the samples contained amorphous carbon. The calculated crystallite size ranged from 3.4 to 6.4 nm for samples synthesised using acetylene at a flowrate of 90 mL/min. For samples synthesised using acetylene at a flowrate of 120 mL/min, the crystallite size ranged from 3.1 to 4.4 nm. Raman spectroscopy confirmed the successful synthesis of MWCNTs; however, the intensity ratio (ID/IG) was found to be above 0.7 for a majority of the samples which confirmed the presence of impurities in the samples. SSA studies revealed that an inversely proportional relationship existed between the SSA and the synthesis temperature. vi HRTEM results for samples synthesised at 650°C and 700°C using ethylene at a flow rate of 90 mL/min (650°C-E90 and 700°C-E90) revealed that CNTs which were MWCNTs in nature were formed. As the synthesis temperature increased from 700°C to 800°C, the formation of what appeared to be non-tubular carbon and carbon nanofibers was observed. The average OD of the tubes ranged from 21 to 84 nm. At a higher ethylene flowrate (120 mL/min), the quality of CNTs seemed to deteriorate for synthesis temperatures above 700°C. The formation of non-tubular carbon-like nanofibers was observed at synthesis temperatures above 700°C. The average OD of the tubes ranged from 11 to 79 nm. XRD analysis of all samples synthesised using ethylene showed a similar pattern with the most intense peak being that of carbon and minor peaks being of iron. However, the depicted minor peaks were broad which suggested that the samples contained amorphous carbon. The calculated crystallite size ranged from 3.7 to 5.7 nm for samples synthesised using ethylene at a flowrate of 90 mL/min. For samples synthesised using ethylene at a flowrate of 120 mL/min, the crystallite size ranged from 3.6 to 6.5 nm. Raman spectroscopy confirmed the successful synthesis of MWCNTs. SSA studies revealed that the SSA decreased with an increase in the synthesis temperature. Furthermore, to evaluate the electrochemical performance of the synthesised material, electrodes of selected samples were fabricated. Commercial graphite electrodes were also fabricated to compare the performance with the samples synthesised in this study. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the electrochemical measurements. The CV tests were conducted at scan rates of 5 mV/s and 10 mV/s, An increase in the CV curve area was observed as the scan rate was increased. The calculated specific capacity of the samples compared well with that of the electrode fabricated with commercial graphite which reported an average of ~197 mAh/g after four cycles at a scan rate of 5 mV/s. The average specific capacity of the electrode fabricated with CNTs sample synthesised at 650°C using ethylene at a flowrate of 120 mL/min (650°C-E120) reported the highest value of 214 mAh/g after four cycles at a scan rate of 5 mV/s. Overall the variation between the samples of the EIS data was marginal. These EIS results also compared well with that of the electrode fabricated with commercial graphite. The findings of this work suggest that MWCNT electrodes have a good application potential and with doping, they may provide better electrochemical performance than graphite as a viable anode material for LIBs.Item Investigation of corrosion behaviour of aluminium alloy 7075 processed by laser shock peening without coating(University of the Witwatersrand, Johannesburg, 2024) Shonhai, Natsai; Cornish, L.A.Laser shock peening (LSP) is a surface treatment to induce beneficial compressive residual stresses in metallic structures, thus improving their fatigue resistance. This technology has the potential to improve aeronautical component performance during application and maintenance. Aluminium alloys are used in the aviation industry due to their high strength-to-weight ratios and ease of design and manufacturing. However, they are susceptible to localised corrosion in some aggressive environments. This study investigated the corrosion behaviour of AA7075-T651 after LSP without a protective coating (LSPwC). Variations in power intensity (PI) of 1-6 GW/cm2, coverage (Np) of 2.5-67 spots/mm2 and spot size (SS) of 0.5-1.5 mm were explored. Surface modifications were evaluated using stereo microscopy, scanning electron microscopy (SEM), contact profilometry and Vickers microhardness tests. Three types of corrosion tests were conducted in 3.5 wt% NaCl solution on the peened and unpeened samples: potentiodynamic polarisation tests, 30-day immersion tests and stress corrosion cracking by three-point bending for 40 days. Microscopic examination revealed rough surfaces with areas of melting and solidification in LSPwC samples. Surface roughness increased in all samples post-LSPwC due to induced plastic deformation and surface ablation. Increasing PI and Np led to increased surface roughness. All peened samples had increased microhardness with a positive correlation with Np. Potentiodynamic polarisation revealed higher corrosion rates for most LSPwC samples, likely due to increased surface roughness which reduced corrosion resistance. Corrosion rate had a positive linear correlation with PI and Np with aluminium oxide formation and pitting as the dominant corrosion mechanisms. Improved corrosion resistance after LSPwC was observed in some samples with specific parameters. Notably, one sample had a corrosion rate four times lower than the unpeened one. The three-point bending induced tensile stresses on the peened surfaces, which led to the formation of multiple tangled cracks on the top surface of all specimens. The LSPwC samples were less susceptible to SCC and the best resistance was observed for Sample P3-SS1-Np50.38 which had no visible cracks in the sample cross-section.Item Development and experimental validation of an acid mine drainage prediction tool based on mineral particles(University of the Witwatersrand, Johannesburg, 2024) Ramatsoma, Mafeni SamuelAcid Mine Drainage (AMD) is an environmental hazard that is generated as a by-product of mining-related activities. It is an acidic metal-rich water formed when sulfide minerals react with oxygen and water. Due to different ore types at different mines, kinetic AMD models are often ‘calibrated’ with kinetic humidity tests done with the target mine site ore. However, most of these tests require several months to complete. This study aimed to investigate ways to reduce the time required to conduct kinetic humidity tests, and to develop a mineral particles-based kinetic AMD model. An Accelerated Humidity Cell (AHC) is proposed in this study. It was tested with two ore types and performed better (produced 24% more acidic-leachates) than normal humidity cells. The particles-based model was developed and tested with experimental data and gave promising results. It is recommended that the proposed model and AHC be further tested with other ore types.Item Modelling of the distribution of coal tar product qualities from a tar distillation plant(University of the Witwatersrand, Johannesburg, 2024) Mokoena, Lehlohonolo Christopher; Brooks, Kevin; Mulopo, JeanThis work presents the simulation modelling and optimisation of a coal tar distillation process to improve the product qualities and increase overall product revenue. The coal tar distillation process consists of three vacuum distillation units and a flash column. The system produces four distillate products: light oil, refined chemical oil (RCO), light creosote, and heavy oil, as well as the residue pitch used as a binder in the manufacturing of electrodes in the aluminium industry. The simulation model was developed in HYSYS using the actual plant mass balance and operating conditions for the production of a residue pitch product with a softening point of 115 – 118 Metller and associated distillates as reference. A mass balance reconciliation technique using an optimiser in HYSYS was applied to fit the plant quality and distillate rate data through adjustment of the Murphee tray efficiencies for each column. The simulation model was validated by simulating the manufacturing of a softer pitch product of softening point 68 – 73 Ring and ball using conditions specified for this particular product and its related distillate products. Through this process, the base conditions were established for the hard and soft pitch production processes. The resultant pitch yield of softening point 115 – 118 M was 42 %, with the light creosote distillate yield at 27 %, as for the softer pitch, the initial yield was estimated at 65 %, and the light creosote at 9,6 %. Following the model development and the establishment of base conditions, a sensitivity analysis focusing on product quality distribution was done to develop an operating philosophy of the process followed by an optimisation process carried out using HYSYS original optimiser to maximise the objective function defined as the sum of product revenue sales with constraints placed on product qualities and adjustable parameters selected as column reflux and boil up ratio as well as the top and bottom temperatures. From the optimisation results, the general adjustment on the first two columns was the drop-down of column top and bottom temperatures by increasing the reflux ratio and reducing the boil-up rate. The light oil product quality in the simulation of a 115 – 118 M pitch improved by decreasing the naphthalene content from 48 % to less than 8,0 % as required by standard operation, with the naphthalene recovery in the RCO stream increasing from 44 % to 67 %. The optimisation process had a large impact on the product yields, where the pitch product 115 – 118 M showed an increase in yield from 42 % to 49 %, which is close to the general yield of 50% mentioned in the literature and normally expected from a coal tar distillation process. and the light creosote distillate product had a positive yield increase of 14 % from the initial value. The overall revenue benefit for the production of a hard pitch improved by an estimated figure of 3,1 % per annum from the initial value (non-optimised condition). In the production of a softer pitch product, the total revenue benefit was 3,2 % higher per annum in comparison to the non-optimised condition.