Tirivaviri Augustine Mamvura

@biust.ac.bw

Senior Lecturer, Faculty of Engineering and Technology
Botswana International University of Science and Technology

Tirivaviri Augustine Mamvura


            Download Compact PDF  
https://researchid.co/atmamvura

RESEARCH, TEACHING, or OTHER INTERESTS

Chemical Engineering, Waste Management and Disposal, Renewable Energy, Sustainability and the Environment, General Chemical Engineering
38

Scopus Publications

Scopus Publications

  • Recovery and purification of graphite from spent lithium-ion batteries through flotation and subsequent leaching
    Wayne Chikwane, Tirivaviri Mamvura, Gwiranai Danha, Tumeletso Lekgoba, Babatunde Obadele, Nkosilamandla Moyo
    Next Energy, 2026
    The purpose of this research is to recover and recycle graphite from spent lithium-ion batteries through the application of flotation and acid leaching. This is to promote the circular economy in the battery manufacturing industry and reduce environmental pollution by waste lithium-ion batteries. This study investigated the effects of collector dosage, pH, and roasting time on the separation of graphite and lithium metal oxides through flotation from black mass of spent lithium-ion batteries. The work also involved the purification of recovered graphite through leaching with HCl. The best flotation conditions were found to be a roasting time of 1 h, collector dosage of 200 g/ton, and pH of 7, resulting in a froth product containing 67.3% fixed carbon (FC). The product was leached with 3 M HCl at 80 °C for 4 h. The final product contained Co, Al, and Cl at concentrations of 6.1%, 0.9%, and 0.7%, while other elements were present at concentrations less than 0.5%. X-ray Diffraction (XRD) showed existence of carbon in multiple phases, with a dominant peak at 2θ = 26.65 ° for raw froth product and 26.48 ° for leached product. Scanning Electron Microscope- Dispersive X-ray Spectroscopy (SEM-EDS) revealed that leaching resulted in a smoother material surface. Raman spectroscopy indicated that crystallinity of the recovered graphite was reduced after leaching, with D-band intensity divided by G-band intensity (ID/IG) ratio increasing to 0.51 for the leached product from 0.24 for raw froth product. The leached product had FC, ash, volatile matter, and moisture contents of 92.5%, 3.6%, 3.9% and 0.2%, respectively. • Graphite can be recovered and purified from spent LIBs through flotation. • Leached froth product contains Co and Al as major impurities. • Leaching results in graphite losing its crystallinity. • The leached froth product has a fixed carbon content of 92.45%. • The recycled graphite has carbon as 5 crystalline phases.
  • The significance of coal ball milling model equations in manufacturing industries
    G. Gaesenngwe, G. Danha, P.V.S Raghupatruni, T.A. Mamvura
    International Journal of Coal Preparation and Utilization, 2026
    The achievable area technique helps engineers optimize milling costs by precisely identifying optimal mill configurations, which results in lower expenses. Research advancements that utilize the achievable region strategic plan and mathematical model equations, have focused on the sustainability of mineral beneficiation by lowering milling power production costs, reducing inputs such as milling time and the number of grinding media employed, minimizing material wastage, and maximizing product yield, among other aspects. This research therefore seeks to optimize coal ball milling processes using an integrated Attainable Region (AR) and Response Surface Methodology (RSM) approach. The coal sample used in this study was obtained from a mine situated in the central region area in Botswana and the AR method was used to quantify the percentage coal mass retained across four optimal class intervals of M1 (−850 µm, +425 µm), M2 (−300 µm, +150 µm), M3 (−106 µm, +80 µm) and M4 (−63 µm). Our main objective was to investigate the application of the integrated approach in reducing the energy consumed during the comminution of this local coal that has been identified for application in the country’s upcoming coal-to-fuels industry. Practically, results obtained from this work shows that Botswana coal is also economically amenable for use in different types of industries including civil engineering, construction, cement manufacturing, pyrolysis, gasification and pharmaceuticals. Our characterization of the coal feed samples revealed that the ash components displayed phases of Quartz (ϱ), Dolomite (ς), Sphalerite (φ), and kaolinite (Δ) minerals mixed with organic maceral. These mineral components greatly influence the coal’s hardness, with strong minerals like sulfides (Sphalerite) and silicates (quartz) enhancing fracture toughness. The total percentage mass retained of all tested coal samples indicated a positive correlation indicating that factors like large mass recovery, material fragmentation, and grind-ability were significantly affected by the coal particle size. type. The response surface method charts displayed the graphical depiction of the quadratic model within 3-dimensional space and illustrate the optimal parameter interactions of a ball-mill operation for run-of-mine coal samples, with the Lack of Fit F-value of 2.99. indicating that the lack of Fit is not considerable when compared to the pure error, as the likelihood of obtaining such a significant Lack of Fit F-value due to random noise is 19.91%. A non-significant lack-of-fit is favorable since we desire the model to align well.
  • Assessing the viability of magnetic separator tailings as a secondary source of nickel, cobalt and copper: a case study for Tati Nickel Mining Company
    Nkosilamandla Moyo, Boitshepo Marakalala, Tshepo Gaogane, Gwiranai Danha, Tirivaviri A. Mamvura
    Journal of Engineering and Applied Science, 2025
    To date, the recovery of nickel and cobalt sulphide minerals from low-grade ores poses significant challenges in mineral processing due to their complex nature. With the decline of rich ore bodies, a paradigm shift to low-grade ores and secondary sources exists for these critical metals, particularly in the renewable energy sector, i.e. storage batteries. This study explores the potential consideration of the magnetic separator tailings obtained from Tati Nickel Mining Company in Botswana as a lucrative base metal secondary resource for the recovery of nickel, cobalt and copper. It becomes a dual approach to obtain valuable base metals while economically handling the waste material to ease the environmental challenges it was posing to the mine and the community. Characterisation of the samples obtained through crystallographic analysis, mineralogy and mapping, and elemental analysis showed the presence of nickel and copper minerals to a degree by which they can be economically extracted through hydrometallurgical means. Cobalt concentration in the sample was in trace amounts as it could only be detectable through the destructive technique. Concentration through froth flotation was conducted post characterisation, with emphasis on flotation time. The optimum flotation time was determined to be 3 minutes, giving metal recoveries of 15.56%, 27.40% and 52% for cobalt, nickel and copper respectively, with an enrichment ratio of 7.39 for copper. However, the yield obtained was 7.04% highlighting the ineffectiveness of the traditional concentration route previously practised in the mine. It was recommended therefore to re-design the flotation process and tailor it for the magnetic separator tailings, concentrating on the effects of pH and particle size distribution primarily, before the other factors, e.g. collectors, modifiers, etc. In conclusion, it was noted that the recovery of nickel, copper and the by-product iron was feasible; therefore, a recommendation was made to apply the Activox technology.
  • Pressurized torrefaction of waste biomass to improve bio coal quality: Synergistic effect between animal waste and wood chips
    N.M. Tshuma, L.B. Moyo, G. Danha, T.A. Mamvura, G.S. Simate, C.D. Artur, G. Charis
    Cleaner Chemical Engineering, 2025
    This study aims to investigate the effect blending waste material to improve its fuel properties using pressurized torrefaction. This research explored the benefits of blending animal waste with wood chips to produce a bio-coal with improved fuel properties. The process conditions investigated were temperature and pressure intervals of 200°C to 280°C and atmospheric pressure (AP) to 4MPa, respectively. The results showed that an increase in temperature and pressure improved the fixed carbon content of the blend almost threefold from 19.87 % to 66.93 % and the higher heating value (HHV) to 27.32MJ/kg from 13.90MJ/kg at mild torrefaction temperature of 280°C and gas pressure of 4MPa compared to atmospheric pressure conditions and the lowest temperature investigated. The HHV increased primarily due to a release of bound and unbound moisture and volatile matter. Wood chips had an HHV of 27.00MJ/kg at a torrefaction temperature of 280°C due to the decomposition of hemicellulose and cellulose which enhanced the thermal stability, fixed carbon content and calorific value. However, animal waste had the least incremental increase in HHV (16.45MJ/kg) due to a high initial content of volatile matter and moisture. The improved properties of the blend of materials indicated that pressurized torrefaction was effective in increasing fixed carbon content through secondary polymerization reactions. Moreover, it facilitated the decomposition of cellulose at a lower temperature than the typical range of 315-400°C if conducted at atmospheric pressure. This study elucidates the notable role of the synergistic effects of blending feed materials prior to torrefaction towards improving the properties and pyrolysis performance of biomass components.
  • Modelling and optimization of ultra-fine copper sulphide grinding: A hybrid statistical and machine learning approach
    Nkosilamandla Moyo, Tirivaviri Mamvura, Gwiranai Danha, Prasad Raghupatruni
    Particuology, 2025
  • Coal-based reduction roasting and magnetic separation of low-grade Botswana iron ore for sustainable beneficiation
    Mompati Mpho Bulayani, Prasad Raghupatruni, Tirivaviri Mamvura, Gwiranai Danha
    Minerals Engineering, 2025
    This study demonstrates a novel pathway to beneficiate low-grade hematite-rich iron ore (56.1 % Fe) from Botswana’s Ikongwe deposit through coal-based magnetizing roasting and low-intensity magnetic separation (LIMS). Leveraging Botswana’s underutilized resources, Morupule non-coking coal (50.01 % fixed carbon, 21.13 % ash) was utilized as a sustainable reductant. A Taguchi L9 orthogonal array systematically optimized critical parameters: roasting temperature (700–900 °C), residence time (30–90 min), and coal dosage (25–50 %). Optimal conditions (800 °C, 60 min, 50 % coal dosage) yielded a magnetic concentrate grading 68.2 % Fe at 85.7 % recovery, representing a 21.6 % relative iron upgrade. Advanced characterization (XRD, SEM-EDS) confirmed efficient phase transformation from hematite to magnetite with concurrent gangue reduction. Kinetic modelling indicated a chemically controlled reaction mechanism, with activation energies ranging from 159.1 to 160.6 kJ/mol. Thermodynamic evaluation revealed negative Gibbs free energy values (ΔG), supporting the spontaneity of the reduction reactions across the tested temperatures. This integrated approach validates the technical and economic feasibility of utilizing Botswana’s local resources to valorise low-grade iron ore, offering a viable route for Botswana to enhance its mineral-based industrialization and to reduce reliance on imported ferrous materials.
  • Prediction of coal ball-mil product stream cost(s) using particle size distribution data
    G. Gaesenngwe, G. Danha, P. V. S. Raghupatruni, T. A. Mamvura
    International Journal of Coal Preparation and Utilization, 2025
    Particle size distribution analysis of a coal ball-mill product stream remains a major challenge for engineers who are manufacturing coal products in several coal firms, due of improper identification of optimum-retained mass yield regions. In our study, experimental data generated from ball-milling of five (5) different coal samples (the run-of-mine coal, cobble coals, nuts coals, peas coals and fine coal type) were reviewed. A new approach was employed that uses a combination of the population balance model (PBM) approach and the volumetric retained mass yield against particle size, obtained from twenty (20) laboratory trials of dry batch grinding. Moreover, the gross power required to generate adequate mass yield at desired size classes was successfully measured using the Stephen Morrell Power Law Model. The resultant estimations were then used to scale up the cost(s) of milling from laboratory to industrial scale. Based on the conclusions, the monetary inputs required for milling different coal types changed proportionally with the coal grindability and hardness of the coal material observed under each coal grade. Coal macerals are formed from fossil fuel deposits and its usage in Africa and the rest of the world is increasingly gaining traction and more than 25% of the world’s electrical power is generated from coal. Additionally, coal size reduction through milling is extremely energy intensive when targeting to process large concentrates of the product stream, hence a proper and more reliable technique that can precisely calibrate a desired particle size and particle size distribution (PSD) is a vital aspect in coal beneficiation.
  • Exploring Low-Grade Iron Ore Beneficiation Techniques: A Comprehensive Review
    Mompati Mpho Bulayani, Prasad Raghupatruni, T. Mamvura, G. Danha
    Minerals, 2024
    The beneficiation of low-grade iron ores is a key research and development topic in the mineral processing industry. The gradual exhaustion of high-grade iron ore reserves, and rising consumer iron and steel demand globally necessitate efficient low-quality iron ore beneficiation to meet steelmaking quality requirements. This comprehensive review explores various beneficiation techniques for low-quality iron ore, focusing on conventional methods including comminution, froth flotation and gravity separation. This article discusses the principles, processes, and equipment used in these techniques and highlights recent advancements and research efforts in the field. This review also emphasizes the importance of effective beneficiation processes in enhancing economic viability, sustainable resource management, and environmental conservation. Furthermore, it presents a case study of iron ore deposits in Botswana, highlighting the potential economic growth and sustainable development that can be achieved by maximizing resource utilization through reductive roasting, followed by magnetic separation of iron ore using semi-bituminous coal as a reductant. Overall, this review provides valuable insights into low-grade iron ore beneficiation techniques and their significance in meeting the growing demand for high-quality iron and steel products.
  • Reclamation of iron and copper from BCL slag in Botswana
    T.S Gabasiane, G. Danha, T. Mashifana, T. Mamvura
    Heliyon, 2024
    <h2>Abstract</h2> High-grade copper ores have been depleted over the years, making it a challenge in the mining industry. This investigation focused on a methodology to recover iron (Fe) and copper (Cu) from a copper/nickel slag obtained from the Bamangwato Concession Limited (BCL) mine in Botswana. In this modified flotation approach, the Response Surface Methodology (RSM) was used in conjunction with the Central Composite Design (CCD) and Analysis of Variance (ANOVA) to obtain the best optimal flotation conditions for the recovery of iron and copper. Using the RSM – CCD methodology, the optimal predicted responses were illustrated by a coefficient of determination R<sup>2</sup> = 0. 9839 for recovery for Fe and 0.9655 for recovery for Cu. The recovery of copper increased with the increasing dosage of Na<sub>2</sub>S and collector dosage, while the increase of pH, had a decrease in recovery of copper due to the decline in the stability of the froth, which led to the resistance to form stable bubbles for efficient recovery of copper. Selective flotation of copper and iron was achieved by varying the Na<sub>2</sub>S dosage to achieve maximum recovery. Under these flotation conditions of PAX (800 g/t), pH (8), −75 μm, sulfurizing agent (Na<sub>2</sub>S, 1000 g/t), flotation time of 8 min, pH regulator of NaOH and <mml:math><mml:mrow><mml:mi>H</mml:mi><mml:mn>2</mml:mn><mml:mrow><mml:mi>S</mml:mi><mml:mi>O</mml:mi></mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:math> and Methyl Isobutyl Carbinol (MIBC) from the experimental runs merited a grade upgrade of Cu in froth concentrate from 0.581 mass% to 0.884 mass%. An enrichment ratio of 2 was realised, with the recovery of Cu being 62%, whereas Fe in the froth concentrate increased from 69.8 mass% to 71.8 mass%. The main aim was to upgrade the grade and recovery of copper and iron to enhance the recovery for copper and iron in the next experimental stage of leaching.
  • A review of the combined torrefaction and densification technology as a source of renewable energy
    Thandiwe Sithole, Godwell Pahla, Tebogo Mashifana, Tirivaviri Mamvura, Elena-Niculina Dragoi, Anbalagan Saravanan, Hasan Sadeghifar
    Alexandria Engineering Journal, 2023
    Densification techniques allow biomass to be used in the energy mix with coal or as a direct replacement for coal as it is a renewable resource. Typically, biomass is bulky, so thermochemical methods, like torrefaction, reduce volatiles and moisture, leaving a higher composition of fixed carbon. After the torrefaction process, the torrefied biomass poses problems during handling, transportation, and storage because it consists of small (<100 μm) disintegrated particles. Densification minimizes these problems through thermal compaction which produces integrated and larger (4 mm – 200 mm diameter) solid particles. This process can be done naturally (without any additives) or by adding binders which improve the torrefied biomass’s physical, chemical, mechanical, and heating properties. This in turn reduces any costs associated with handling/transportation and storage of the biomass before it is used for energy generation. Densification increases the biomass’s energy content per unit volume thereby enabling coal substitution. Recent reviews on densification have mainly focused on the binding of coal fines, raw biomass, and some torrefied biomass. Reviews on the binding theories are also available. This current review focuses solely on the aspect of torrefied biomass densification and the factors associated with the process. Insights and recommendations for the possible application of an integrated biomass torrefaction and densification process were provided herein. In addition, the gaps in literature were identified to enable future research on the application of the process to realize innovative renewable energy production in industry.
  • Recovering phosphorus as struvite from anaerobic digestate of pig manure with ferrochrome slag as a magnesium source
    L.B. Moyo, G.S. Simate, T.A. Mamvura, G. Danha
    Heliyon, 2023
  • Application of Attainable Region Technique to Optimize Copper Slag’s Desired Size Class
    Tlotlo Solomon Gabasiane, Gwiranai Danha, Tirivaviri Mamvura, Tebogo Mashifana, Vusumuzi Sibanda
    Minerals, 2023
  • Magnesium recovery from ferrochrome slag: kinetics and possible use in a circular economy
    L.B. Moyo, G.S. Simate, T.A. Mamvura
    Heliyon, 2022
  • Overview of Torrefaction Technologies: A Path Getaway for Waste-to-Energy
    Tirivaviri A. Mamvura
    Handbook of Waste Biorefinery Circular Economy of Renewable Energy, 2022
  • Selective flocculation and recovery of chrome from plant slimes using starch and sodium oleate as flocculants
    V. Sibanda, LehAnA MAkARA, LeRATO SeBOSe, ThULAgAnyO SeTIMO, T. Mamvura, G. Danha
    Gospodarka Surowcami Mineralnymi Mineral Resources Management, 2022
  • Environmental and socioeconomic impact of copper slag—A review
    Tlotlo Solomon Gabasiane, Gwiranai Danha, Tirivaviri A. Mamvura, Tebogo Mashifana, Godfrey Dzinomwa
    Crystals, 2021
  • A comparative study on the comminution behavior of diorite rocks
    Gaesenngwe Gaesenngwe, Tirivaviri Mamvura, Gwiranai Danha, Vusumuzi Sibanda
    Heliyon, 2021
  • Characterization of copper slag for beneficiation of iron and copper
    T.S. Gabasiane, G. Danha, T.A. Mamvura, T. Mashifana, G. Dzinomwa
    Heliyon, 2021
  • Investigating the effect of lip froth washing on coal yield during flotation of a high ash South African coal
    Cherryl du Plessis, Vusumuzi Sibanda, Marek Dworzanowski, Gwiranai Danha, Tirivaviri Mamvura
    Physicochemical Problems of Mineral Processing, 2021
  • Adsorption of lead ions from wastewater using nano silica spheres synthesized on calcium carbonate templates
    Milton Manyangadze, Nyaradzai M.H. Chikuruwo, T. Bala Narsaiah, Ch. Shilpa Chakra, Gratitude Charis, Gwiranai Danha, Tirivaviri A. Mamvura
    Heliyon, 2020
  • Integrated and consolidated review of plastic waste management and bio-based biodegradable plastics: Challenges and opportunities
    Zvanaka S. Mazhandu, Edison Muzenda, Tirivaviri A. Mamvura, Mohamed Belaid, Trust Nhubu
    Sustainability Switzerland, 2020
  • Optimisation of using a blend of plant based natural and synthetic coagulants for water treatment: (Moringa Oleifera-Cactus Opuntia-alum blend)
    B.I. Gandiwa, L.B. Moyo, S. Ncube, T.A. Mamvura, L.L. Mguni, N. Hlabangana
    South African Journal of Chemical Engineering, 2020
  • The development of a waste tyre pyrolysis production plant business model for the gauteng region, South Africa
    Nhlanhla Nkosi, Edison Muzenda, Tirivaviri A. Mamvura, Mohamed Belaid, Bilal Patel
    Processes, 2020
  • Production of modified bitumen from used engine oil, coal tar and waste tyre for construction applications
    Nyaradzo Kamoto, Joseph Govha, Gwiranai Danha, Tirivaviri Mamvura, Edison Muzenda
    South African Journal of Chemical Engineering, 2020
  • Optimization of pulp production from groundnut shells using chemical pulping at low temperatures
    P. Musekiwa, L.B. Moyo, T.A. Mamvura, G. Danha, G.S. Simate, N. Hlabangana
    Heliyon, 2020
  • Biomass torrefaction as an emerging technology to aid in energy production
    T.A. Mamvura, G. Danha
    Heliyon, 2020
  • Enhancing the flotation recovery of copper minerals in smelter slags from Namibia prior to disposal
    V. Sibanda, E. Sipunga, G. Danha, T.A. Mamvura
    Heliyon, 2020
  • Characterization of botswana coal from two coal fields: Mabesekwa and mmamabula to determine its coal rank
    Mmoloki Makoba, , Taboka Moalosi, Paul S. Agachi, Edison Muzenda, Tirivaviri A. Mamvura, , , , , and
    Studia Universitatis Babes Bolyai Chemia, 2020
  • Production of activated carbon from poultry feathers for waste water treatment
    Rue Chiramba, Gratitude Charis, Nonhlanhla Fungura, Gwiranai Danha, Tirivaviri Mamvura
    Water Science and Technology, 2019
  • The potential application of graphene nanotechnology for renewable energy systems
    Tirivaviri A. Mamvura, Geoffrey S. Simate
    Graphene Based Nanotechnologies for Energy and Environmental Applications, 2019
  • Energy changes during use of high-power ultrasound on food grade surfaces
    Tirivaviri A. Mamvura, Sunny E. Iyuke, Anthony E. Paterson
    South African Journal of Chemical Engineering, 2018
  • Torrefaction of waste biomass for application in energy production in South Africa
    T.A. Mamvura, G. Pahla, E. Muzenda
    South African Journal of Chemical Engineering, 2018
  • Energy densification of animal waste lignocellulose biomass and raw biomass
    G. Pahla, T.A. Mamvura, F. Ntuli, E. Muzenda
    South African Journal of Chemical Engineering, 2017
  • The impact of pipe geometry variations on hygiene and success of orbital welding of brewing industry equipment
    T. A. Mamvura, A. E. Paterson, D. Fanucchi
    Journal of the Institute of Brewing, 2017
  • Investigation on the effect of ultrasound waves on stainless steel surfaces during removal of soil films
    Advances in Environmental Biology, 2014
  • Immobilisation of yeast cells on carbon nanotubes
    Tirivaviri A. Mamvura, Sunny E. Iyuke, Vusumuzi Sibanda, Clarence S. Yah
    South African Journal of Science, 2012
  • Soil films in the beverage industry: A review
    T. A. Mamvura, S. E. Iyuke, J. D. Cluett, A. E. Paterson
    Journal of the Institute of Brewing, 2011
  • Process synthesis and optimization for the production of carbon nanostructures
    S E Iyuke, T A Mamvura, K Liu, V Sibanda, M Meyyappan, V K Varadan
    Nanotechnology, 2009