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The impact of microwave pre-treatment on the liberation of Nb/Ta minerals from a Tin oxide ore

- Mutombo, David, Nheta, Willie, Kalenga, Michel

  • Authors: Mutombo, David , Nheta, Willie , Kalenga, Michel
  • Date: 2018
  • Subjects: Cassiterite , Microwave pre-treatment , Niobium
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/280992 , uj:30222 , Citation: Mutombo, D., Nheta, W. & Kalenga, M. 2018. The impact of microwave pre-treatment on the liberation of Nb/Ta minerals from a Tin oxide ore.
  • Description: Abstract: Liberation of Nb/Ta minerals from Cassiterite ore during comminution is difficult. Microwave pre-treatment of cassiterite ore using batch multiple mode microwave was done. The ore was characterised and effects of various parameters affecting the liberation of Nb/Ta minerals were investigated. It was found that the ore contains 76. 1%wt of SnO2 and traces of Nb2O5 (0.62% wt) and Ta2O5 (0.81% wt). The major phases in the cassiterite ore after pre-treatment were Pyrochlore, Cassiterite, Sillimanite, Ferrotapiolite, Niobium Tantalum, Niobium Titanium, Iron Tin, Niobium Tin, Iron Tantalum and Niobium tin silicide. The ore displayed a significant liberation of the Nb and Ta minerals at 100% irradiation and a high temperature of 540 ̊C was achieved. Significant phase changes were observed from the SEM/EDS and the Mapping of the distribution of the Nb/Ta minerals showed that there was an improvement in the liberation of these minerals. It is concluded that the use of microwaves brings changes in the matrix pattern of the Cassiterite ore, favouring the liberation of microwave susceptible mineral phases.
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Effect of CaO/MgO ratio on the product quality during tin smelting

- Mutombo, David, Kalenga, Michel, Nheta, Willie

  • Authors: Mutombo, David , Kalenga, Michel , Nheta, Willie
  • Date: 2018
  • Subjects: Cassiterite , Slag basicity , Smelting
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/279939 , uj:30072 , Citation: Mutombo, D., Kalenga, M. & Nheta, W. 2018. Effect of CaO/MgO ratio on the product quality during tin smelting.
  • Description: Abstract: The existing tin smelting processes have the disadvantages of high smelting temperature, long smelting time and especially high tin losses. In this paper, the effect of basicity on the product quality during tin smelting was studied by monitoring the CaO/MgO ratio. It was found that the iron content in the metal product depends on the Fe/Sn ratio in the slag. A high tin metal product (98.52% Sn and 1.02% Fe) was obtained and a small loss of Sn went into the slag (<10%) at a reduction temperature of 14000C and basicity of 1.2. The low Fe content in the Sn metal would make the subsequent tin refining easier. The Nb and Ta content in the slag increased to 4.96 and 5.06% respectively. The main phases in the slag were Ferrocolumbite, Niobium oxide and Tantalum oxide. The recovery was high for Sn in the metal and Nb/Ta in the slag.
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Beneficiation of haematite from fluorspar tailings by reverse flotation

- Nheta, Willie, Lubisi, Thembelihle Portia, Masemola, Selby, Makhatha, Mamookho Elizabeth

Recovery of PGMS from mine sludge by leaching

- Nheta, Willie, Mapotsane, Kutullo

  • Authors: Nheta, Willie , Mapotsane, Kutullo
  • Date: 2017
  • Subjects: Mine sludge , Leaching , Oxidizing agents
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/239288 , uj:24580 , Citation: Nheta, W. & Mapotsane, K. 2017. Recovery of PGMS from mine sludge by leaching.
  • Description: Abstract: South Africa host massive deposits of Platinum Group Metals (PGMs) in the Igneous Bushveld Complex. These deposits have been mined for a long time and in the process Mine sludge has been produced. It has been piled up and there is need to recover PGMs locked in it. The conventional way of processing PGMs has proved to be very difficult due to ultra-fines in the sludge that causes major loses during flotation. An alternative hydrometallurgical process for recovery of PGMs from a mine sludge by leaching using a mixture of hydrochloric acid and different oxidizing agents was investigated. It was found that the mine sludge contained 8.93 g/t Pt, 6.99 g/t Pd, 2.79 g/t Ru and minor percentages of Rh, Ir, and Au. It had a particle size distribution (PSD) of 84.64% passing 38 microns. Major mineral phases present are sphalerite, chalcopyrite, pentlandite, covellite, bornite, chromite, and silica as the main gangue. HCL + H2O2 (1:1) combination managed to leach all the PGMs and gold. HCL + Ferric Chloride (1:1) combination managed to leach Pt, Rh and Ru very well but it could not leach Pd. Further investigation on the optimization of the leaching conditions is being done.
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Pelletization of iron ore concentrate from fluorspar tailings

- Nheta, Willie, Mashigo, Jeanette

  • Authors: Nheta, Willie , Mashigo, Jeanette
  • Date: 2017
  • Subjects: Pelletization , Agglomeration , Flotation
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/239275 , uj:24579 , Citation: Nheta, W. & Mashigo, J. 2017. Pelletization of iron ore concentrate from fluorspar tailings.
  • Description: Abstract: Many low grade iron ore deposits which were previously ignored are being treated due to depletion of high grade iron ore deposits. Haematite flotation concentrate from a reverse flotation of fluorspar tailings was characterised and agglomerated using bentonite and coke. The effect of bentonite and coke concentrations on mechanical strength and metallurgical characteristics of the wet and baked pellets was investigated. It was found that the concentrate contained 60.5% Fe, 4.24% silica and other minor elements. Major mineral phases present were hematite, magnetite and silica. A maximum wet drop number of 3 and wet strength of 2.85N was obtained when using 1.25 and 0.75wt% bentonite respectively. The maximum dry and baked strength obtained was 28.1N and 2690N respectively whilst using 1.25wt% bentonite and no coke. Porosity of the baked pellets was not affected very much with change in coke concentration which is not the usual case with iron ores. At high coke concentration (3wt %), the pellets contained spinels.
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Characterization and beneficiation of low grade Nb AND Ta ore from Kibara belt

- Mutombo, David, Nheta, Willie

  • Authors: Mutombo, David , Nheta, Willie
  • Date: 2017
  • Subjects: Niobium , Tantalum , Flotation
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/239075 , uj:24552 , Citation: Mutombo, D. & Nheta, W. 2017. Characterization and beneficiation of low grade Nb AND Ta ore from Kibara belt.
  • Description: Abstract: Due to their chemical, physical and mechanical properties, niobium (Nb) and tantalum (Ta) are strategically used in various technical applications. About 130 different minerals contain tantalum and niobium, of which only about 80 are found in economical deposits. The remainder contains Nb and Ta as impurities. The most commercialised source of Nb and Ta is a columbite-tantalite ore often referred to as coltan containing pyrochlorite. The Central African Mesoproterozoic Kibara belt in Katanga (Democratic Republic of Congo) forms a metallogenic province that hosts a variety of granite-related mineralization, rich in cassiterite, columbite–tantalite, wolframite/ferberite, spodumene and beryl. This study focuses on the characterization of Nb/Ta ores from the Kibara belt by using the XRF, SEM/EDS, XRD and ICP-OES. It was observed that Nb/Ta ore that occurs in this belt has a high Nb/Ta ratio. The grade of the ore is 0.01wt% Ta and 0.04wt% Nb. The major minerals phases are Tapiolite, Tantalite, Simpsonite, Pyrochlore and Ilmenorutile. The major gangue minerals present locking Nb/Ta are silica, feldspars with small amounts of mica and quartz. The size of the particles containing Nb/Ta are 8-12microns. Basing on these results, flotation is proposed at as the suitable way of concentrating this ore.
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Flotation of nickel-copper sulphide ore : optimisation of process parameters using Taguchi method

- Masiya, Trust T., Nheta, Willie

  • Authors: Masiya, Trust T. , Nheta, Willie
  • Date: 2014
  • Subjects: Froth flotation , Taguchi method , Nickel-copper sulphide ore
  • Type: Article
  • Identifier: uj:4795 , http://hdl.handle.net/10210/12047
  • Description: Froth flotation is widely used for concentration of base metal sulphide minerals in complex ores. One of the major challenges faced by flotation of these ores is the ever varying grade and mineralogy. This therefore calls for a continual characterisation and optimisation of flotation parameters such that concentrator performance as a whole is always maintained. In this study, the robust Taguchi experimental design method was used to determine the optimum conditions for the flotation of nickel, copper and cobalt from a nickel-copper sulphide ore. The parameters investigated include collector dosage, percentage solids, depressant dosage and pH. The effects of these parameters at three different levels on the recovery of Ni, Cu and Co were investigated using an L9 Taguchi orthogonal array. The optimum conditions for the recovery of the base metals are collector dosage, 80g/t; pH, 10.15; %solids, 25; and depressant dosage, 100g/t. Relative significance of flotation parameters (based on difference between max and min. values) indicates that pH has the most significant effect on the recovery of nickel, copper and cobalt during flotation. Analysis of variance showed that pH and depressant dosage were the most significant parameters affecting the recovery of Ni, while collector dosage and percentage solids were insignificant. None of the tested parameters significantly affected copper recovery whilst pH was found to also significantly affect cobalt recovery.
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Investigation on the correlation of degree of weathering to pit depth on platinum group metals recovery by flotation

- Letseli, Mohale, Nheta, Willie, Steinmuller, Arno

  • Authors: Letseli, Mohale , Nheta, Willie , Steinmuller, Arno
  • Date: 2019
  • Subjects: Platinum group metals (PGMs) , Flotation , Selectivity index
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/399395 , uj:33286 , Citation: Letseli, M., Nheta, W. & Steinmuller, A. 2019. Investigation on the correlation of degree of weathering to pit depth on platinum group metals recovery by flotation.
  • Description: Abstract: Processing of weathered material from UG2 ore for recovery of Platinum group minerals (PGMs) is a challenging task due to poor recoveries and high chromite grade in the flotation concentrates. The flotation behaviour of the weathered and non-weathered ores of Middle Group 4 (MG 4) was investigated at different mining pit depths using sodium isobutyl xanthate as a collector, Sendep 30D as depressant and Senfroth 200 as a frother. The milling tests work were conducted prior to flotation. The results depicted that, the weathered ore is relatively soft and contained less chrome content as compared to non-weathered ore. The head grades of the surface ore and at a pit depth of 918 m was relatively the same assaying at 2.49 and 2.62 ppm respectively for the 4Es (Platinum, Palladium, Rhodium and Gold). The recovery and grade of PGMs at the rougher flotation cell was increasing with the increase in pit depth with the concentrate from surface weathered ore assaying 22.40 ppm and 47.07 ppm for the ore from 918 m depth for 4 Es. High chromite content in the flotation concentrate is due to blending of pristine ore and oxidized ore. Therefore, the correlation between degree of weathering, pit depth and recovery can be drawn for MG4 ore.
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A review of lanthanum nanoparticles impregnated compound arsenic fixation behaviour in copper aqueous solution

- Emmanuel, Bamidele, Makhatha, Elizabeth, Nheta, Willie

Recovery of nickel from reverberatory furnace slag by sulfurization and flotation

- Nheta, Willie, Kalenga, Michel, Rasivhetshele, Ndivhuwo

  • Authors: Nheta, Willie , Kalenga, Michel , Rasivhetshele, Ndivhuwo
  • Date: 2019
  • Subjects: Flotation , Nickel , Sulfurization
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/399403 , uj:33287 , Citation: Nheta, W., Kalenga, M. & Rasivhetshele, N. 2019. Recovery of nickel from reverberatory furnace slag by sulfurization and flotation.
  • Description: Abstract: Due to depletion of high-grade ores, high cost of mining and environmental issues, many mines have reverted to retreatment of slags. The recovery of Nickel from reverberatory furnace slag using sulfurization and flotation was studied. Critical parameters such as sulfurization temperature, sulfurization agent (Gypsum containing 86.87% CaSO4) dosage and time were investigated for the sulfurization process and effect of collector type and dosage, pH, particle size and flotation time for the flotation process. It was found that the slag contained 0.37% Cu and 0.19 % Ni as Copper oxide and Nickel oxide and other mineral phases such as fayalite, cuprospinnel and pentlandite. Optimum conditions for sulfurization were addition 20g of gypsum, 8g of Coke at a temperature of 950 􀔨 under inert environment (argon) in a tube furnace for one hour. All of the Nickel oxide was sulfurized to Nickel sulfide and Millerite. 88.3 % Nickel was recovered after flotation under optimum conditions of 0.20g/t Potassium amyl xanthate (PAX), 5 drops of Dowfroth 200, 80% passing 75 microns at a pH of 7 in a micro flotation cell. The recovery of Nickel sulphide was very much dependent on collector dosage.
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Effect of time on formation of phases in the slag during tin production

- Mutombo, David Ilunga, Wa Kalenga, Michel Kalenga, Nheta, Willie

  • Authors: Mutombo, David Ilunga , Wa Kalenga, Michel Kalenga , Nheta, Willie
  • Date: 2018
  • Subjects: Cassiterite , Smelting , Reduction time
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/282037 , uj:30384 , Citation: Mutombo, D.I., Wa Kalenga, M.K. & Nheta, W. 2018. Effect of time on formation of phases in the slag during tin production.
  • Description: Abstract: Most cassiterite ores contain a certain amount of niobium and tantalum, which report to the slag during tin production. The reduction time is said to enhance the formation of some phases which preferentially dissolve some metals than others. The current paper investigates the effect of time on the phases that form in the slag during reduction and the preferential dissolution of Nobium and Tantalum in some phases. XRD, XRF, SEM-EDS were used to analyse the head sample and the products of the smelting process. The basicity was kept at 1 with the addition of dolomite. Carbon was used as reducing agent and an alumina tube furnace for the reduction. Graphite crucible was used and CO was blown in the furnace to minimise the reaction between the sample and the crucible. Experiments were conducted at different reduction times. The time varied from 30minutes to 2hours with 30 minutes intervals at 1400oC. Results showed that Nobium and Tantalum are preferentially dissolved in Monticellite, Ferrocolumbite, Fayalite, Tantalum oxide and Niobium oxide, the two oxides reaching 5% in the slag while the purity of metal reached a maximum of 99% of Sn and 1% Fe.
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Investigation on the mechanisms of bio‐processing vanadium slags

- Ntita, Joelle, Nheta, Willie

  • Authors: Ntita, Joelle , Nheta, Willie
  • Date: 2017
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/226003 , uj:22840 , Citation: Ntita, J. & Nheta, W. 2017. Investigation on the mechanisms of bio‐processing vanadium slags. 5th International Slag Valorisation Symposium, Leuven, 3‐5/04/2017.
  • Description: Abstract: Due to depletion of high grade ore deposits and reinforcement of environmental regulations, many mines have resorted to use mine waste as a secondary source of metals. This minimises waste disposal and at the same time generates revenues. Vanadium slag is one of the by-products of steelmaking operations and between 25 000 and 30 000 tons are produced annually by the South African industry. This calls for alternative vanadium recovery from the slag that would be efficient and environmentally less hazardous. Bioleaching is a viable and sustainable method that will meet these requirements. This study focuses on the recovering of vanadium from the slags us! ing the microorganisms and on the reaction mechanisms. The bioleaching process was mimicked by leaching with acids under a temperature of 25oC, 2% percent solids, concentration of 150mM and an agitation of 150rev/min for 120minutes. It was found that the dissolution of vanadium from the raw slag while leaching with gluconic, citric and oxalic acid was 2.5, 3.4 and 6.1% respectively. Further studies will include choosing bacteria that produces oxalic acid, investigate the leaching process and the reaction mechanisms.
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Characterisation and Flotation of a Weathered Platinum Group Metal ore

- Letseli, Mohale, Nheta, Willie, Steinmuller, Arno

Leaching of nickel from a jarosite precipitate with hydrochloric acid

- Nheta, Willie, Makhatha, Mamookho E.

  • Authors: Nheta, Willie , Makhatha, Mamookho E.
  • Date: 2013
  • Subjects: Hydrochloric acid , Leaching , Nickel , Jarosite precipitates
  • Type: Article
  • Identifier: uj:4969 , http://hdl.handle.net/10210/13070
  • Description: Jarosite precipitates produced at Impala’s Base Metal Refineries contain substantial amounts of nickel. Laboratory-scale experiments were carried out in an attempt to recover nickel by leaching with hydrochloric acid. The leaching efficiency of nickel was 60% at 25oC. The acid concentration of 0.5 – 1 molar, pulp density of 10% and leaching time of 90 min was found to be optimum under the present conditions. High pH could break the jarosite structure and release more iron into the solution which will adversely affect the following precipitation process to recover nickel. 27% of the nickel lost is by entrainment. The reaction is diffusion independent.
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Characterisation of jarosite, fly ash and clay for their possible usage in the construction industry

- Makhatha, Mamookho E., Ndou, Muneiwa O., Nheta, Willie, Mubiayi, Patrick M.

  • Authors: Makhatha, Mamookho E. , Ndou, Muneiwa O. , Nheta, Willie , Mubiayi, Patrick M.
  • Date: 2015-07-20
  • Subjects: Clay , Jarosite , Fly-ash
  • Type: Article
  • Identifier: uj:5165 , http://hdl.handle.net/10210/14402
  • Description: In this paper, the mineralogical and physical characterisation of Jarosite, Clay and Fly ash was investigated. The XRD results revealed the presence of alacranite (AsS) and jarosite (K (Fe3(SO4)2(OH)6)) mineral phases in the hazardous jarosite, while clay was composed of Kaolinite (Al2Si2O5 (OH)4), Anatase (TiO2) and Quartz (SiO2). Furthermore, Fly ash contained phases Mullite (Al4.64Si1.36O9.68), Quartz (SiO2) and Calcium oxide silicate chloride (Ca2O2Si3Cl2). The XRF results confirmed that the Fly ash used is in class F (Hazardous material) . There were hazardous elements such as As and Pb in the Jarosite sample. Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM/EDS) revealed differences in surfaces morphology and EDS results were in agreement with the XRF analysis. The densities of the samples were 3.13 g/cm3 , 2.67 g/cm3 and 2.21 g/cm3 for Jarosite, clay and Fly ash respectively. There was an increase in density with the increase of the percentage of Jarosite in the mixture whereas a decrease in density was noticed with the increase of Fly ash percentage in the mixture of Jarosite and clay.
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Use of waste gypsum from hydrometallurgical plant for the recovery of nickel from a Nickel slag by sulfurization

- Chauke, Nurse, Kalenga, Michel, Nheta, Willie

  • Authors: Chauke, Nurse , Kalenga, Michel , Nheta, Willie
  • Date: 2018
  • Subjects: Sulfurization , slag , CaSO4
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/282012 , uj:30382 , Citation: Chauke, N., Kalenga, M. & Nheta, W. 2018. Use of waste gypsum from hydrometallurgical plant for the recovery of nickel from a Nickel slag by sulfurization
  • Description: Abstract: Disposal of waste in the metallurgical industry has become a challenge. Heaps of gypsum from hydrometallurgical plants using sulphates media are growing and pose an environmental problem. The current investigation focuses on the use of disposed gypsum from hydrometallurgical plants for Nickel recovery from slag. Sulfurization tests were carried out at different temperatures ranging from 600⁰C to 1250⁰C. XRD, XRF, ICP-MS and SEM-EDS were used for characterization. A silica crucible was used as a container placed in a tube furnace under argon gas to enhance the reaction. Nickel and Copper content in the slag were 0.75 and 1.16% respectively. The major phases were fayalite, cuprospinnel and nickel oxide. Results showed that the recycling of gypsum from hydrometallurgical plants was beneficial and the increase in temeperature favored to convert nickel oxide into sulphide. Peacks decomposition has proved a number of sulphides have formed. However, above 1100⁰C the sulfurization decreased.
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Evaluation of a platinum group metal flotation re-cleaner stage performance and possible improvement

- Nheta, Willie, Mphahlele, Karabo

  • Authors: Nheta, Willie , Mphahlele, Karabo
  • Date: 2019
  • Subjects: Platinum-group mineral , Flotation , Chromite
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/400038 , uj:33368 , Citation: Nheta, W. & Mphahlele, K. 2019. Evaluation of a platinum group metal flotation re-cleaner stage performance and possible improvement.
  • Description: Abstract: South Africa has massive Platinum Group Metal (PGM) deposits found in Bushveld Igneous Complex (BIC). Due to depletion of Merensky reef, many companies are now treating UG2 reef which has a high chromite content which has negative impact in the smelting process of the platinum concentrates. Generally, PGMs are processed by rougher followed by cleaner and re-cleaner flotation banks and the final concentrate must contain less than 3% chromite. The effect of residence time and depressant dosage on PGM recovery and chromite entrainment on the recleaner stage was investigated by floating the feed to the re-cleaner banks using Dow froth 200, Cu2SO4, sodium isobutyl xanthate and carboxymethyl cellulose in a 3l Denver cell. It was found that extra 30g/t of depressant dosage (carboxymethyl cellulose) from standard conditions reduces the chromite content to 2.11% from 8.63% and only 37.54% of PGMs are lost to the recleaner tailings which are recirculated to the cleaner feed. The residence time was reduced by 15minutes from the normal residence time. The Malvern particle size analyzer results indicated that the increase in depressant dosage and decrease in residence time the finer the concentrate. By controlling the depressant dosage, amount of chromite content in the final concentrate can effectively be reduced to meet the required standards.
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Purification of platinum metal refinery crystalliser effluent using ion-exchange

- Nheta, Willie, Ntuli, Freeman, Mulaba-Bafubiandi, Antoine F., Makhatha, Elizabeth

  • Authors: Nheta, Willie , Ntuli, Freeman , Mulaba-Bafubiandi, Antoine F. , Makhatha, Elizabeth
  • Date: 2014
  • Subjects: Ion exchange , Impala Platinum Metal Refinery , Crystallised salts
  • Type: Article
  • Identifier: uj:4796 , http://hdl.handle.net/10210/12048
  • Description: Impala Platinum Metal Refinery (PMR) produces about 30 tonnes of salt every month after crystallisation of effluent from the refining processes. These crystallised salts contain impurities (heavy metals) and are discarded. This poses a danger to the environment and it costs the company large amount money to correctly dump them. There is need to find ways of purifying these salts and find its alternative industrial uses. Major sectors identified using industrial salt were paper mills, pharmaceutical, textile, tanning and paint industrial sectors (Department of Minerals and Energy, 2001). Comparison of the salt composition with salt specifications required for these uses revealed that the salt needed further purification in order to find application in these industrial sectors. Two approaches were proposed; treatment of the crystallized salt to remove impurities and treatment of the crystallizer influent stream before crystallization to ensure a more pure salt is produced...
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Flotation of low-grade iron ore using macadamia oil as a frother

- Nheta, Willie, Phasha, Felicia

  • Authors: Nheta, Willie , Phasha, Felicia
  • Date: 2019
  • Subjects: Reverse flotation , Macadamia oil , Natural oil
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/407431 , uj:34295 , Citation: Nheta, W., Phasha, F. 2019: Flotation of low-grade iron ore using macadamia oil as a frother.
  • Description: Abstract: Froth flotation process has shown superiority in processing of many low-grade ores including iron ores. However, there is need to continue developing cheap, more selective and environmentally friendly reagents. Due to the shortage of high-grade iron ores, many companies in South Africa and other countries are currently working on the beneficiation of low-grade ores and retreatment of tailings. In this paper, the performance of Macadamia oil as a frother on the flotation of low-grade iron ore was investigated. The critical flotation parameters such as frother and collector dosage, pH, particle size distribution and air flowrate addition on the reverse flotation of low-grade iron ore was studied. The results revealed that the ore assayed 50.35, 3.45 and 4.41% of Fe, Si and F respectively. The major phases were hematite, quarts and fluorspar. The results of the reverse flotation of low-grade iron ore from a fluorspar flotation tailing indicated that the reagent combination of 400 g/t Dodecylamine collector, 5 g/t Macadamia oil at a pH of 8.5, 35 % solids and 2.5 L/minute air flowrate with a particle size distribution of 80% passing 75 microns produced a concentrate assaying 61.60 % Fe and 2.48 % Si at a recovery of 65.21 % Fe. Flotation pH was the most sensitive parameter. Macadamia oil has huge potential in the flotation of low-grade iron ores.
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Optimisation of gold recovery from small scale custom mills

- Nheta, Willie, Nkwinika, Mahlori, Mailula, Moselyn

  • Authors: Nheta, Willie , Nkwinika, Mahlori , Mailula, Moselyn
  • Date: 2020
  • Subjects: Gold , Small scale mining , Artisanal mining
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/450654 , uj:39623 , Citation: Nheta, W., Nkwinika, M. & Mailula, M. 2020. Optimisation of gold recovery from small scale custom mills.
  • Description: Abstract: Custom mill tailings generated during the treatment of gold ores in Custom milling plants contains a considerable significant amount of gold (Au) and Silver (Ag). The potential of recovering gold and silver from the tailings by cyanidation leaching process was investigated. The custom mill tailings were characterised using Malvern particle analyser, XRF, XRD and SEM-EDs. In this study, the MiniTab software experimental design method was used to determine the optimum leaching conditions. The PSD results revealed that the custom mill tailings are coarse with 80% passing 2000μm. The tailings are a quartzite material containing minor amount of sulphides such as pyrite, chalcopyrite and pentlandite. The amount of these sulphides is very low ruling the probability of the tailings being refractory. Recoveries of 88 and 95% for gold and silver respectively were achieved leaching at 800g/t NaCN 8hrs. However, gold recovery above 85% was achieved by leaching in 600g/t NaCN for 8 hrs. Custom mill tailings have proved to be a source of precious metals and Min Tab software is a useful tool in optimisation of the leaching conditions.
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