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$Furnace refractory erosion - Mintek$

Pics from topto bottom:Flotationpilot-plantcampaign onNkomati ore.The NkomatiNickel Mine(photocourtesyNkomatiNickel).Pilot-plantoperatorstake samplesfrom themanganesesolventextractioncircuitto purifythe cobaltelectrolytebeforeelectro-Copperelectro-the KOVPCMZ, Nkomati’s nickel reserves have increased by 50 percent – to 485 377 tons. The by-product reserves have also43 per cent, and 4.181 million ounces of PGMs, a 70 per centincrease. Based on these positive results, LionOre and ARMcommissioned DRA to proceed with a bankable feasibility studyfor the large-scale expansion of the concentrator plants.The proposed large-scale expansion, planned for 2010, willincorporate mining of the PCMZ, increasing annual productionto approximately 20 000 tons of nickel and extending the life ofthe mine to beyond 2020. An interim expansion exploiting thedisseminated MMZ will maintain nickel production at its currentlevel of about 5 000 tons per year after the massive sulphidemineralisation is depleted in 2008.Mintek has carried out process development work for a numberof copper-cobalt projects in Zambia and the DRC. Among thesea South African mining company in the DRC for many years. Thestarted up in September 2006. The second phase, which will involvecobalt metal on-site at Ruashi, is under construction.Mintek began bench and pilot work, which would be used in the bankablefeasibility study for phase II of the project, in April 2006. Three campaignswere conducted, and the work was completed during March 2007.In the design of the solvent-extraction and electrowinning circuit, Mintekworked closely with Metorex’s design company, TWP Matomo ProcessPlant. The plant has been designed for a capacity of 120 000 tons of ore permonth. When the phase II expansion is completed, production at Ruashi isexpected to increase to 45 000 tons of copper cathode and approximately 3500 tons of cobalt metal and cobalt carbonate per annum.A major process development campaign was conducted for the KOV coppercobaltproject, also in the DRC. A total of 27 tons of material was delivered tolaboratory tests to determine the optimum leach conditions, integrated piloting of theleaching, copper solvent extraction and electrowinning circuit, and Aspen simulationLME Grade A standard (higher than 99.95 per cent copper), were produced. The KOVcomplex, which contains one of the world’s largest high-quality copper and cobaltresources, is being re-developed by Nikanor plc. The project will include a major27 500 tons per year of cobalt products.Dense-media separation, milling, and leaching testwork were carried out to investigate aGreen Team Consultants International.Mintek has been involved in numerous projects to remove iron and manganese fromdilute cobalt sulphate solutions by oxidative precipitation using air/SO 2. This technologyis attractive as it can be done at ambient temperature, relatively low pH, and ferrousiron is quantitatively removed within 1-2 hours. In order to produce cobalt cathode of thedesired quality, iron, manganese, copper, zinc, and aluminium must generally be removedfrom the feed to electrowinning. The requirements to produce an intermediate cobalt saltare generally less stringent, but usually iron, aluminium, and manganese still need to beremoved.annual report 2007 26
The recent interest shown in this technology by emergingcopper-cobalt producers in central Africa has encouraged Mintekto do some work to identify potential scale-up issues. Variousagitators and gas induction systems were investigated, and a highshearimpeller designed and supplied by Outotec was selected forfurther testwork on a 2 m 3 scale to examine the effects of parameterssuch as SO 2and temperature on the process. Optimisation tests remain to be doneon power consumption and various aspects around gas induction.Two smelting campaigns were conducted on discard slag from BCL inBotswana to compare the use of AC and DC furnaces for recoveringnickel and copper. The results showed that both technologies were equallyeffective, and that the company could substantially improve the recoveriesin its slag-cleaning operation by adding reductant to the existing settlingfurnaces.Pics from top tobottom:The Outotechigh-shearimpeller.LaboratoryNicksyn TMreagent insupport of theat Tali Nickel.The thermalMagnesiumProcess demonstrationplant.The Mintek-developed nickel synergist (Nicksyn) was evaluated tooptimise nickel recovery and nickel-calcium separation at Tati Nickel inBotswana. Laboratory test work was conducted at Mintek on the feed to thenickel solvent-extraction circuit to optimise the combination of the synergistand the Versatic 10 commercial extractant, and the results applied on theActivox® hydrometallurgical demonstration plant at Tati using a 0.5 toncommercial batch of Nicksyn.on the organic phase, which could result in gypsum formation inthe extraction circuit if the feed becomes saturated with calcium.Previously, Tati Nickel minimised the problem by diluting the feedstream with fresh water, but this would increase the size of theproduction. Furthermore, with Versatic 10, the pH of extractioncannot be increased as this causes higher calcium loadings -extraction stages).With the synergistic system, the calcium loading was aboutone-tenth that obtained previously, and gypsum formation canbe completely avoided. The Versatic-Nicksyn combination alsoachieved higher nickel recoveries (99.7 per cent comparedwith about 99.3 per cent) using only four stages. In addition,lower reagent losses were experienced, which can be ascribedto the much lower pH of operation and the reduction in crudeformation.Work continued on the production of titanium-aluminium masteralloys by aluminothermic reduction, and a project is in progressat the University of Cape Town on the fundamental aspects of thetitanium-aluminium-oxygen-carbon-nitrogen system to determinethe best criteria for scale-up.Following a review of the economics of the Mintek ThermalMagnesium Process, Anglo American has decided not to pursuecommercialisation, since it is felt that it would not be able tocompete with the low-cost Chinese producers. Mintek will continue tolook for opportunities for applying the technology.27annual report 2007
Page 1 and 2: MINTEKANNUALREPORT2007
Page 3 and 4: MINTEKANNUAL REPORT2007CONTENTSMint
Page 5 and 6: THE MINING VALUE CHAINTechnologies
Page 7 and 8: CHAIRMAN’S REVIEWI am pleased to
Page 9 and 10: Mr Harold Motaung, and new members
Page 11 and 12: CEO’S REPORTAs a result of the ph
Page 13 and 14: income grew frommillion in 2006/07,
Page 15 and 16: of the Mineral Development Branch a
Page 17 and 18: Organisational perspective Measure
Page 19 and 20: TECHNICAL REVIEWGOLD INDUSTRYAuTEK
Page 21 and 22: expected to be complete by the four
Page 23 and 24: of ore types and concentrate compos
Page 25 and 26: vast resources of iron, vanadium, a
Page 27: partitioned into several operating
Page 31 and 32: oute to remove the quartz and hemat
Page 33 and 34: COMMERCIALACTIVITIESMintek’s comm
Page 35 and 36: Heap leaching of nickel lateritesHe
Page 37 and 38: CAPITAL EQUIPMENTA 125 kilogram per
Page 39 and 40: MINERAL POLICYAND SUSTAINABLEDEVELO
Page 41 and 42: REACHAt the beginning of 2006, MESU
Page 43 and 44: KGABANE JEWELLERY INITIATIVEThe Kga
Page 45 and 46: PEOPLEHUMAN CAPITAL MANAGEMENTMinte
Page 47 and 48: management, relationships, and lega
Page 49 and 50: Science, engineering and technology
Page 51 and 52: Jourdan PP. Links with Domestic Ind
Page 53 and 54: ANNUALFINANCIAL STATEMENTSFOR THE Y
Page 55 and 56: INTERNAL CONTROLMintek maintains in
Page 57 and 58: AUDIT COMMITTEE REPORTThe Audit Com
Page 59 and 60: DIRECTORS’ REPORTThe directors ta
Page 61 and 62: REPORT OF THE AUDITOR-GENERALREPORT
Page 63 and 64: OTHER REPORTING RESPONSIBILITIESRep
Page 65 and 66: FINANCIAL STATEMENTS AND NOTES 2007
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FINANCIAL STATEMENTS AND NOTES 2007
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AfDB - African Development BankAMI
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