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Acid mine drainage (AMD) and red mud (RM) are frequently available in the metallurgical and mining industry. Treating AMD solutions require the generation of enough alkalinity to neutralize the acidity excess. RM, recognized as a waste generating high alkalinity solution when it is in contact with water, was chosen to treat AMD from South Africa at room temperature. A German and a Greek RM have been evaluated as a potential low-cost material to neutralize and immobilize harmful chemical ions from AMD. Results showed that heavy metals and other hazardous elements such as As, Se, Cd, and Zn had been immobilized in the mineral phase. According to European environmental standards, S and Cr, mainly present in RM, were the only two elements not immobilized below the concentration established for inert waste.
Hugo Lucas; Srecko Stopic; Buhle Xakalashe; Sehliselo Ndlovu; Bernd Friedrich. Synergism Red Mud-Acid Mine Drainage as a Sustainable Solution for Neutralizing and Immobilizing Hazardous Elements. Metals 2021, 11, 620 .
AMA StyleHugo Lucas, Srecko Stopic, Buhle Xakalashe, Sehliselo Ndlovu, Bernd Friedrich. Synergism Red Mud-Acid Mine Drainage as a Sustainable Solution for Neutralizing and Immobilizing Hazardous Elements. Metals. 2021; 11 (4):620.
Chicago/Turabian StyleHugo Lucas; Srecko Stopic; Buhle Xakalashe; Sehliselo Ndlovu; Bernd Friedrich. 2021. "Synergism Red Mud-Acid Mine Drainage as a Sustainable Solution for Neutralizing and Immobilizing Hazardous Elements." Metals 11, no. 4: 620.
Salt in Uganda is mainly imported from neighboring countries despite the existence of a 22.5 million t of mineral deposit at Lake Katwe, Western Uganda. Earlier attempts to extract salt from the deposit did not yield the required results. To reduce on the salt import bill and improve the livelihoods of the local miners, a modified solar concentration process was designed to extract sodium chloride and other evaporites. The process flow sheets describing the constituent unit operations were modeled using SuperPro Designer. A bench-scale experiment guided by thermodynamic calculations from the PHREEQC software was conducted to validate the process flow sheets. XRD results show that halite of > 99% purity was produced after the flotation of burkeite and trona. Furthermore, soda ash and sodium sulfate were produced after the second evaporation process by a combination of flotation, carbonation, and calcination techniques. Sodium chloride is the most abundant and feasible product. The unit production cost of sodium chloride was 0.2629 and 0.4724$/kg with a net present value of $2,447,853 and − 12,085,796 of the solar salt and mechanical evaporation processes respectively. As a result, the solar salt extraction process proved highly feasible from both engineering and economic standpoints and thus can be scaled up to a pilot scale using conventional industrial equipment.
Joseph Ddumba Lwanyaga; Hillary Kasedde; John Baptist Kirabira; Alan Shemi; Sehliselo Ndlovu. Process Design and Economic Evaluation for the Recovery of Halite and Co-products from Lake Katwe Brine. Process Integration and Optimization for Sustainability 2021, 1 -16.
AMA StyleJoseph Ddumba Lwanyaga, Hillary Kasedde, John Baptist Kirabira, Alan Shemi, Sehliselo Ndlovu. Process Design and Economic Evaluation for the Recovery of Halite and Co-products from Lake Katwe Brine. Process Integration and Optimization for Sustainability. 2021; ():1-16.
Chicago/Turabian StyleJoseph Ddumba Lwanyaga; Hillary Kasedde; John Baptist Kirabira; Alan Shemi; Sehliselo Ndlovu. 2021. "Process Design and Economic Evaluation for the Recovery of Halite and Co-products from Lake Katwe Brine." Process Integration and Optimization for Sustainability , no. : 1-16.
Acid mine drainage (AMD), red mud (RM) and coal fly ash (CFA) are potential high environmental pollution problems due to their acidity, toxic metals and sulphate contents. Treatment of acidic mine water requires the generation of enough alkalinity to neutralize the excess acidity. Therefore, red mud types from Germany and Greece were chosen for the neutralization of AMD from South Africa, where this problem is notorious. Because of the high alkalinity, German red mud is the most promising precipitation agent achieving the highest pH-values. CFA is less efficient for a neutralization and precipitation process. An increase in temperature increases the adsorption kinetics. The maximum pH-value of 6.0 can be reached by the addition of 100 g German red mud at 20 °C to AMD-water with an initial pH value of 1.9. German red mud removes 99% of the aluminium as aluminium hydroxide at pH 5.0. The rare earth elements (yttrium and cerium) are adsorbed by Greek red mud with an efficiency of 50% and 80% at 60 °C in 5 min, respectively.
Viktoria Keller; Srecko Stopic; Buhle Xakalashe; Yiqian Ma; Sehliselo Ndlovu; Brian Mwewa; Geoffrey Simate; Bernd Friedrich. Effectiveness of Fly Ash and Red Mud as Strategies for Sustainable Acid Mine Drainage Management. Minerals 2020, 10, 707 .
AMA StyleViktoria Keller, Srecko Stopic, Buhle Xakalashe, Yiqian Ma, Sehliselo Ndlovu, Brian Mwewa, Geoffrey Simate, Bernd Friedrich. Effectiveness of Fly Ash and Red Mud as Strategies for Sustainable Acid Mine Drainage Management. Minerals. 2020; 10 (8):707.
Chicago/Turabian StyleViktoria Keller; Srecko Stopic; Buhle Xakalashe; Yiqian Ma; Sehliselo Ndlovu; Brian Mwewa; Geoffrey Simate; Bernd Friedrich. 2020. "Effectiveness of Fly Ash and Red Mud as Strategies for Sustainable Acid Mine Drainage Management." Minerals 10, no. 8: 707.
This paper critically discusses the structure, properties and applications of ironmaking and steelmaking slags and their silicate-based variants as low-cost adsorbents for removing cations and anions from industrial effluents and wastewater. Undoubtedly, the performance of slag-based adsorbents depends on their physical, chemical and phase chemical properties. The presence of crystalline phases, for example, has a significant effect on the adsorption capacity. However, despite their low cost and ubiquity, their chemical and geometric heterogeneity significantly affects the performance and applications of slag-based adsorbents. These challenges notwithstanding, the efficacy of slag-based adsorbents can be significantly enhanced through purposeful activation to increase the specific surface area and density of adsorption sites on the surfaces of adsorbent particles. The synthesis of functionalised adsorbents such as geopolymers, zeolites and layered double hydroxides from silicate and aluminosilicate precursors can also significantly increase the performance of slag-based adsorbents. In addition, the ability to stabilise the dissolved and/or entrained toxic metal species in stable phases in slags, either through controlled post-process fluxing or crystallisation, can significantly enhance the environmental performance of slag-based adsorbents. Most critical in the design of future slag-based adsorbents is the integration of the engineered properties of molten and solidified slags to the recovery and stabilisation of dissolved and/or entrained metals.
James Manchisi; Elias Matinde; Neil A. Rowson; Mark J. H. Simmons; Geoffrey S. Simate; Sehliselo Ndlovu; Brian Mwewa. Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities. Sustainability 2020, 12, 2118 .
AMA StyleJames Manchisi, Elias Matinde, Neil A. Rowson, Mark J. H. Simmons, Geoffrey S. Simate, Sehliselo Ndlovu, Brian Mwewa. Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities. Sustainability. 2020; 12 (5):2118.
Chicago/Turabian StyleJames Manchisi; Elias Matinde; Neil A. Rowson; Mark J. H. Simmons; Geoffrey S. Simate; Sehliselo Ndlovu; Brian Mwewa. 2020. "Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities." Sustainability 12, no. 5: 2118.
The wastes generated from both operational and abandoned coal and metal mining are an environmental concern. These wastes, including acid mine drainage (AMD), are treated to abate the devastating effects they have on the environment before disposal. However, AMD contains valuable resources that can be recovered to subsidize treatment costs. Two of the major constituents of coal AMD are iron and aluminium, which can be recovered and engineered to function as coagulants. This work examines the potential of producing a poly-alumino-ferric sulphate (AMD-PAFS) coagulant from coal acidic drainage solutions. The co-precipitation of iron and aluminium is conducted at pH values of 5.0, 6.0 and 7.0 using sodium hydroxide in order to evaluate the recovery of iron and aluminium as hydroxide precipitates while minimizing the co-precipitation of the other heavy metals. The precipitation at pH 5.0 yields iron and aluminium recovery of 99.9 and 94.7%, respectively. An increase in the pH from 5.0 to 7.0 increases the recovery of aluminium to 99.1%, while the recovery of iron remains the same. The precipitate formed at pH 5.0 is used to produce a coagulant consisting of 89.5% and 10.0% iron and aluminium, respectively. The production of the coagulant is carried out by dissolving the precipitate in 5.0% (w/w) sulphuric acid. Subsequently, the treatment of the brewery wastewater shows that the AMD-PAFS coagulant is as efficient as the conventional poly ferric sulphate (PFS) coagulant. The turbidity removal is 91.9 and 87.8%, while the chemical oxygen demand (COD) removal is 56.0 and 64.0% for AMD-PAFS and PFS coagulants, respectively. The developed process, which can easily be incorporated into existing AMD treatment plants, not only reduces the sludge disposal problems but also creates revenue from waste.
Brian Mwewa; Srećko Stopić; Sehliselo Ndlovu; Geoffrey S. Simate; Buhle Xakalashe; Bernd Friedrich. Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation. Metals 2019, 9, 1166 .
AMA StyleBrian Mwewa, Srećko Stopić, Sehliselo Ndlovu, Geoffrey S. Simate, Buhle Xakalashe, Bernd Friedrich. Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation. Metals. 2019; 9 (11):1166.
Chicago/Turabian StyleBrian Mwewa; Srećko Stopić; Sehliselo Ndlovu; Geoffrey S. Simate; Buhle Xakalashe; Bernd Friedrich. 2019. "Synthesis of Poly-Alumino-Ferric Sulphate Coagulant from Acid Mine Drainage by Precipitation." Metals 9, no. 11: 1166.
Electronic waste (e-waste) contains valuable materials such as metals. These may be recovered using conventional pyrometallurgical or hydrometallurgical processes. However, these existing metal recovery techniques have a number of limitations such as adverse environmental footprints and high energy costs. This then necessitate an investigation into alternative methods or reagents. In this research, ionic liquids; [Bmim][Tf2N], [Bmim][PF6], and Cyphos 101 were investigated as extractants for Ag and Au from chloride aqua regia leach liquors of printed circuit board samples, with the composition of 162 gt-1 Au and 618 gt-1 Ag. The ionic liquids used were found to be efficient extractants for Au extraction from the leach liquor, with more than 90% of Au extracted in all the ionic liquids tested. Ag extraction was however, found to be lower compared to Au with no extraction recorded for [Bmim][Tf2N] but over 90% extraction was recorded for both Cyphos 101 and [Bmim][PF6]. This showed that ionic liquids are potential alternative extractants for the recovery of Au and Ag from chloride media. Considering both costs and efficiency, Cyphos 101 proved to be the most effective extractant for all metals from chloride solution at room temperature and 1:1 of the IL: sample ratio. The extractions were 95% Ag, 97% Au and 99% Cu under these conditions.
Mthobisi Masilela; Sehliselo Ndlovu. Extraction of Ag and Au from chloride electronic waste leach solutions using ionic liquids. Journal of Environmental Chemical Engineering 2018, 7, 102810 .
AMA StyleMthobisi Masilela, Sehliselo Ndlovu. Extraction of Ag and Au from chloride electronic waste leach solutions using ionic liquids. Journal of Environmental Chemical Engineering. 2018; 7 (1):102810.
Chicago/Turabian StyleMthobisi Masilela; Sehliselo Ndlovu. 2018. "Extraction of Ag and Au from chloride electronic waste leach solutions using ionic liquids." Journal of Environmental Chemical Engineering 7, no. 1: 102810.
High carbon ferrochrome slag is a byproduct of High Carbon Ferrochrome (HCFeCr) production in submerged arc furnaces. The slag is conventionally tapped from the furnaces and granulated before being dumped as waste. The major uses of the slag have been in road and civil engineering construction and in production of refractories. HCFeCr slags however, contain appreciable amounts of residual ferrochrome alloy which can be liberated and recovered profitably using cheap and environmentally friendly gravity concentration methods. In this work the milling behavior of a high-carbon ferrochrome slag is investigated. Milling experiments for a typical HCFeCr slag were conducted using a 0.303 by 0.282 m laboratory ball mill to establish liberation as a function of particle size and to determine the associated key breakage parameters like the breakage function (Bij) and selection function (Si). The breakage parameters were obtained using the monosize fraction method by milling the following size fractions − 13.2 + 9.5 mm, − 9.5 + 5.6 mm, − 5.6 + 4 mm, − 4 + 2.8 mm, − 2.8 + 1.18 mm and − 1.18 + 0.15 mm. The effects of powder filling and mill speed were also tested experimentally. An increase in the milling speed from 75% Ncrit to 85% Ncrit caused an increase in the selection functions of different fractions however a further increase to 90% Ncrit resulted in a drastic reduction in the rate of milling across all size fractions. Increasing the powder filling from 40% to 60% caused a marked increase in the selection functions for the particles in the size fraction − 5.6 + 4 mm and smaller and a decrease in the selection functions for the particles in the size fraction − 9.5 + 5.6 mm and larger. A further increase in the powder filling to 80% caused a marked fall in the selection functions for all size fractions to values lower than those obtained at 40% powder filling. The results from the size by assay test-work showed that the sizes of particles that contain the highest amount of the ferrochrome alloy and the least amount of silica are in the range − 1.18 + 0.6 mm. The milling process has to maximize the generation of particles in this specific size range in order to achieve the best alloy recoveries in the downstream concentration unit.
Vusumuzi Sibanda; Refilwe Kopong; Sehliselo Ndlovu; Ratombo Zwanga. Ball milling of high carbon ferro chrome slag to liberate the alloy for gravity concentration. International Journal of Mineral Processing 2016, 157, 46 -54.
AMA StyleVusumuzi Sibanda, Refilwe Kopong, Sehliselo Ndlovu, Ratombo Zwanga. Ball milling of high carbon ferro chrome slag to liberate the alloy for gravity concentration. International Journal of Mineral Processing. 2016; 157 ():46-54.
Chicago/Turabian StyleVusumuzi Sibanda; Refilwe Kopong; Sehliselo Ndlovu; Ratombo Zwanga. 2016. "Ball milling of high carbon ferro chrome slag to liberate the alloy for gravity concentration." International Journal of Mineral Processing 157, no. : 46-54.
Rhulani N. Ntimbani; Geoffrey S. Simate; Sehliselo Ndlovu. Removal of copper ions from dilute synthetic solution using staple ion exchange fibres: Equilibrium and kinetic studies. Journal of Environmental Chemical Engineering 2015, 3, 1258 -1266.
AMA StyleRhulani N. Ntimbani, Geoffrey S. Simate, Sehliselo Ndlovu. Removal of copper ions from dilute synthetic solution using staple ion exchange fibres: Equilibrium and kinetic studies. Journal of Environmental Chemical Engineering. 2015; 3 (2):1258-1266.
Chicago/Turabian StyleRhulani N. Ntimbani; Geoffrey S. Simate; Sehliselo Ndlovu. 2015. "Removal of copper ions from dilute synthetic solution using staple ion exchange fibres: Equilibrium and kinetic studies." Journal of Environmental Chemical Engineering 3, no. 2: 1258-1266.
Geoffrey S. Simate; Sehliselo Ndlovu. The removal of heavy metals in a packed bed column using immobilized cassava peel waste biomass. Journal of Industrial and Engineering Chemistry 2015, 21, 635 -643.
AMA StyleGeoffrey S. Simate, Sehliselo Ndlovu. The removal of heavy metals in a packed bed column using immobilized cassava peel waste biomass. Journal of Industrial and Engineering Chemistry. 2015; 21 ():635-643.
Chicago/Turabian StyleGeoffrey S. Simate; Sehliselo Ndlovu. 2015. "The removal of heavy metals in a packed bed column using immobilized cassava peel waste biomass." Journal of Industrial and Engineering Chemistry 21, no. : 635-643.
Sehliselo Ndlovu; Geoffrey S. Simate; Kudzai A. Mchibwa; Alejandra Giaveno. Characterization of nanoprecipitates formed from the forced hydrolysis of bioleach liquors under different pH conditions. Journal of Industrial and Engineering Chemistry 2014, 20, 3578 -3583.
AMA StyleSehliselo Ndlovu, Geoffrey S. Simate, Kudzai A. Mchibwa, Alejandra Giaveno. Characterization of nanoprecipitates formed from the forced hydrolysis of bioleach liquors under different pH conditions. Journal of Industrial and Engineering Chemistry. 2014; 20 (5):3578-3583.
Chicago/Turabian StyleSehliselo Ndlovu; Geoffrey S. Simate; Kudzai A. Mchibwa; Alejandra Giaveno. 2014. "Characterization of nanoprecipitates formed from the forced hydrolysis of bioleach liquors under different pH conditions." Journal of Industrial and Engineering Chemistry 20, no. 5: 3578-3583.
Geoffrey S. Simate; Sehliselo Ndlovu. Acid mine drainage: Challenges and opportunities. Journal of Environmental Chemical Engineering 2014, 2, 1785 -1803.
AMA StyleGeoffrey S. Simate, Sehliselo Ndlovu. Acid mine drainage: Challenges and opportunities. Journal of Environmental Chemical Engineering. 2014; 2 (3):1785-1803.
Chicago/Turabian StyleGeoffrey S. Simate; Sehliselo Ndlovu. 2014. "Acid mine drainage: Challenges and opportunities." Journal of Environmental Chemical Engineering 2, no. 3: 1785-1803.
Doris Oke; Sehliselo Ndlovu; Vusumuzi Sibanda. Removal of platinum group metals from dilute process streams: Identification of influential factors using DOE approach. Journal of Environmental Chemical Engineering 2014, 2, 1061 -1069.
AMA StyleDoris Oke, Sehliselo Ndlovu, Vusumuzi Sibanda. Removal of platinum group metals from dilute process streams: Identification of influential factors using DOE approach. Journal of Environmental Chemical Engineering. 2014; 2 (2):1061-1069.
Chicago/Turabian StyleDoris Oke; Sehliselo Ndlovu; Vusumuzi Sibanda. 2014. "Removal of platinum group metals from dilute process streams: Identification of influential factors using DOE approach." Journal of Environmental Chemical Engineering 2, no. 2: 1061-1069.
A. Shemi; S. Ndlovu; V. Sibanda; Lizelle van Dyk. Extraction of aluminium from coal fly ash: Identification and optimization of influential factors using statistical design of experiments. International Journal of Mineral Processing 2014, 127, 10 -15.
AMA StyleA. Shemi, S. Ndlovu, V. Sibanda, Lizelle van Dyk. Extraction of aluminium from coal fly ash: Identification and optimization of influential factors using statistical design of experiments. International Journal of Mineral Processing. 2014; 127 ():10-15.
Chicago/Turabian StyleA. Shemi; S. Ndlovu; V. Sibanda; Lizelle van Dyk. 2014. "Extraction of aluminium from coal fly ash: Identification and optimization of influential factors using statistical design of experiments." International Journal of Mineral Processing 127, no. : 10-15.
The production of carbon nanostructures, including carbon nanotubes (CNTs), by chemical vapour deposition (CVD) occurs by thermally induced decomposition of carbon-containing precursors. The decomposition of the feedstock leading to intermediate reaction products is an important step, but rarely incorporated in rate equations, since it is generally assumed that carbon diffusion through or over the catalyst nanoparticles is the rate-limiting step in the production of CNTs. Furthermore, there is no kinetic model to date for the production of CNTs from carbon dioxide. These aspects are addressed in this study with the aid of a series of experiments conducted in a floating catalytic CVD reactor in which the effects of reactor temperature, concentration and flow rate of CO2 were investigated. A simple rate equation for the reductive adsorption of CO2 onto the catalyst surface followed by carbon diffusion leading to the production of CNTs is proposed as follows: d[CNT]/dt = K[CO2], where K is proportional to the diffusion coefficient of carbon. The derived kinetic model is used to calculate the amount of CNTs for a given concentration of CO2, and the experimentally measured data fits the simple rate equation very well at low carbon dioxide concentration.
Geoffrey S. Simate; Kapil Moothi; M. Meyyappan; Sunny E. Iyuke; Sehliselo Ndlovu; Rosemary Falcon; Mike Heydenrych. Kinetic model of carbon nanotube production from carbon dioxide in a floating catalytic chemical vapour deposition reactor. RSC Advances 2014, 4, 9564 .
AMA StyleGeoffrey S. Simate, Kapil Moothi, M. Meyyappan, Sunny E. Iyuke, Sehliselo Ndlovu, Rosemary Falcon, Mike Heydenrych. Kinetic model of carbon nanotube production from carbon dioxide in a floating catalytic chemical vapour deposition reactor. RSC Advances. 2014; 4 (19):9564.
Chicago/Turabian StyleGeoffrey S. Simate; Kapil Moothi; M. Meyyappan; Sunny E. Iyuke; Sehliselo Ndlovu; Rosemary Falcon; Mike Heydenrych. 2014. "Kinetic model of carbon nanotube production from carbon dioxide in a floating catalytic chemical vapour deposition reactor." RSC Advances 4, no. 19: 9564.
In this twenty-first Century, Africa is still lagging behind both in the development and utilization of new cost-effective and high-productive technologies. This is expected to remain so for a long time to come. The lack of technological innovations and monetary investments are some of the key factors that are viewed as contributing to Africa‘s perpetual underdevelopment and economic instability. In this context, sound technology transfer and acquisition can play an active role in African development and economic sustainability. This chapter looks at how appropriate technology transfer can enhance economic development in Africa, with particular focus on two specific areas, namely Biotechnology and Nanotechnology. Concurrently, this chapter also reviews and discusses some of the key factors that generally impede technology transfer in Africa. Equally, this chapter also addresses some of the merits and demerits of technology transfer, in particular as related to the African continent and its quest for sustainable development and economic growth. Both Biotechnology and Nanotechnology are relatively new, but these are hot technologies that have great potential in many industrial sectors where they can serve to cost-effectively optimize operational processes, increase efficiency, and maximize productivity.
Geoffrey S. Simate; Sehliselo Ndlovu; Sunny E. Iyuke; Lubinda F. Walubita. Biotechnology and Nanotechnology: A Means for Sustainable Development in Africa. Chemistry for Sustainable Development in Africa 2012, 159 -191.
AMA StyleGeoffrey S. Simate, Sehliselo Ndlovu, Sunny E. Iyuke, Lubinda F. Walubita. Biotechnology and Nanotechnology: A Means for Sustainable Development in Africa. Chemistry for Sustainable Development in Africa. 2012; ():159-191.
Chicago/Turabian StyleGeoffrey S. Simate; Sehliselo Ndlovu; Sunny E. Iyuke; Lubinda F. Walubita. 2012. "Biotechnology and Nanotechnology: A Means for Sustainable Development in Africa." Chemistry for Sustainable Development in Africa , no. : 159-191.
Nyaradzo Chigumbu, Sunny Iyuke, Viness Pillay and Sehliselo Ndlovu-In Vitro Evaluation Of The Physicochemical Effects Of Drug Loaded Carbon Nanotubes On Toxicity
Nyaradzo Chigumbu; Sunny Iyuke; Viness Pillay; Sehliselo Ndlovu. In Vitro Evaluation Of The Physicochemical Effects Of Drug Loaded Carbon Nanotubes On Toxicity. Journal of Nanomedicine & Nanotechnology 2012, 3, 1 .
AMA StyleNyaradzo Chigumbu, Sunny Iyuke, Viness Pillay, Sehliselo Ndlovu. In Vitro Evaluation Of The Physicochemical Effects Of Drug Loaded Carbon Nanotubes On Toxicity. Journal of Nanomedicine & Nanotechnology. 2012; 3 (4):1.
Chicago/Turabian StyleNyaradzo Chigumbu; Sunny Iyuke; Viness Pillay; Sehliselo Ndlovu. 2012. "In Vitro Evaluation Of The Physicochemical Effects Of Drug Loaded Carbon Nanotubes On Toxicity." Journal of Nanomedicine & Nanotechnology 3, no. 4: 1.
Knowing the significance that a factor has in influencing a measured response is paramount for optimisation and cost control. The significant factors can be optimised while the insignificant ones can be set at levels where the least cost is incurred. The purpose of this study was to investigate the factors that influence the dissolution of nickel laterites using a mixed culture of chemolithotrophic bacteria ( Acidithiobacillus ferrooxidans , Acidithiobacillus caldus and Leptospirillum ferrooxidans ). The significance of each factor and their interactive effects were evaluated using statistical design of experiments quarter fractional factorial designs 2 III 5 − 2 and dissolved nickel was taken as the measured response. The factors under this study included pulp density, particle size, pH, size of bacterial inoculum and substrate type. Results obtained indicated that inoculum size was not statistically significant while the rest of the factors were statistically significant. Under the ranges studied the interaction between the variables was found to be statistically insignificant, apart from that between pulp density and type of substrate. The results also showed that recovery was maximized at low pH and low pulp density. In the range studied, particles of less than 38 μm had a negative influence on nickel recovery. Sulphur substrate also showed better effects than pyrite. Keywords Nickel laterites Chemolithotrophic microorganisms Heterotrophs DOE
Geoffrey S. Simate; Sehliselo Ndlovu. Bacterial leaching of nickel laterites using chemolithotrophic microorganisms: Identifying influential factors using statistical design of experiments. International Journal of Mineral Processing 2008, 88, 31 -36.
AMA StyleGeoffrey S. Simate, Sehliselo Ndlovu. Bacterial leaching of nickel laterites using chemolithotrophic microorganisms: Identifying influential factors using statistical design of experiments. International Journal of Mineral Processing. 2008; 88 (1-2):31-36.
Chicago/Turabian StyleGeoffrey S. Simate; Sehliselo Ndlovu. 2008. "Bacterial leaching of nickel laterites using chemolithotrophic microorganisms: Identifying influential factors using statistical design of experiments." International Journal of Mineral Processing 88, no. 1-2: 31-36.
G.S. Simate; Sehliselo Ndlovu. Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments. THERMEC 2006 Supplement 2007, 66 -69.
AMA StyleG.S. Simate, Sehliselo Ndlovu. Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments. THERMEC 2006 Supplement. 2007; ():66-69.
Chicago/Turabian StyleG.S. Simate; Sehliselo Ndlovu. 2007. "Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments." THERMEC 2006 Supplement , no. : 66-69.
Identifying influential factors in the bacterial leaching of nickel laterites using a mixed culture of chemolithotrophic micro-organisms was explored using the approach of statistical design of experiments. In a series of experiments, pH, particle size, pulp density, type of substrate and inoculum size were statistically combined using a quarter fractional factorial designs 2 5−2 III and tested for their influence on nickel recovery using chemolithotrophic microorganisms. The results indicated that inoculum size was not statistically significant while the rest of the factors were statistically significant. Under the ranges studied the interaction between the variables was found to be weak. The results also showed that recovery was maximized at low pH and low pulp density. In the range studied, particles of less than 38μm had a negative influence on nickel recovery. Sulphur substrate also showed better effects than pyrite.
Geoffrey S. Simate; Sehliselo Ndlovu. Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments. Advanced Materials Research 2007, 20-21, 66 -69.
AMA StyleGeoffrey S. Simate, Sehliselo Ndlovu. Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments. Advanced Materials Research. 2007; 20-21 ():66-69.
Chicago/Turabian StyleGeoffrey S. Simate; Sehliselo Ndlovu. 2007. "Characterisation of Factors in the Bacterial Leaching of Nickel Laterites Using Statistical Design of Experiments." Advanced Materials Research 20-21, no. : 66-69.