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Structural, compositional and mineralogical characterization of carbonatitic copper sulfide: Run of mine, concentrate and tailings

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International Journal of Minerals,Metallurgy and Materials 2019年第2期26卷 143-151页

作者： Kolela J Nyembwe Elvis Fosso-Kankeu frans waanders Kasongo D Nyembwe Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals Engineering Faculty of Engineering North-West University School of Mining Metallurgy and Chemical Engineering Faculty of Engineering and the Built Environment University of Johannesburg

The aim of this study was to determine the structural, compositional, and mineralogical composition of carbonatitic copper sulfide concentrator plant streams. Three samples, each from a different stream(run of mine(ROM), concentrate, and tailings) of a copper concentrator were characterized using various techniques, including stereomicroscopy, X-ray fluorescence, X-ray diffraction, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM) in conjunction with energy-dispersive X-ray spectroscopy(EDS), and optical microscopy. The results reveal that each stream possesses its own unique compositional features. Carbonate minerals associated with calcite and dolomite, followed by quartz, remain the major minerals in both the ROM and tails streams. In the ROM stream, chalcopyrite appears to occur as veins within the carbonatite-hosting ore body. Mineral phase mutation was discovered in the tails stream because magnetite formerly identified in the ROM as the primary iron oxide had evolved into hematite. This metamorphosis was likely promoted by the concentration process. The concentration process was effective, upgrading the chalcopyrite content from 2 wt% in the ROM stream to 58 wt% in the concentrate stream; it was accompanied by bornite(4 wt%), anilite(3 wt%), and digenite(2.5 wt%). In addition, the concentrate stream exhibited properties distinctive from those of the other streams. The FTIR analysis showed the existence of a sulfide group related to the chalcopyrite mineral. Free chalcopyrite grains were observed in the concentrate by SEM analysis, and their mineral presence was supported by the EDS analysis results. All characterization techniques corresponded well with each other regarding the structure, chemistry, and composition of the samples.

关键词： chalcopyrite mineral characterization phase mutation concentrate streams

Economic overview of a two-agent process for underground coal gasification with Fischer-Tropsch- based poly-generation

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Clean Energy 2019年第1期3卷 34-46页

作者： Johan F.Brand Johan C.van Dyk frans B.waanders African Carbon Energy PO Box 450Standerton 2430South Africa Centre of Excellence in Carbon-based Fuels North-West UniversityPotchefstroom 2520South Africa African Carbon Energy PO Box 254SasolburgSouth Africa

Underground Coal Gasification(UCG)is a mining-gasification process that produces synthesis gas from in situ coal by injecting air(or oxygen and steam)and extracting the produced gas via *** resulting synthesis gas(‘syngas’)produced by UCG can be used directly as a fuel-gas or deep-cleaned to produce many other products like chemicals,liquid fuels,hydrogen and synthetic natural *** has significant environmental,safety and practical advantages over conventional coal mining and utilization,foremost being cost and emissions *** South Africa,facilities of an industrial-scale Fischer-Tropsch(FT)have been operating for decades on coal-to-liquid and gas-to-liquid ***-blown UCG produces syngas,which contains a mixture of carbon monoxide(CO)and hydrogen,and these molecules can be conditioned to serve as feed for synthetic-crude-oil(‘syncrude’)conversion technologies based on the FT *** Carbon Energy(Pty)Ltd.(Africary)completed a study integrating its UCG technology with mini gas-to-liquids *** from Africary’s Theunissen Underground Coal Gasification(TUCG)project will be used for power production and synthesis of liquid fuels in a unique poly-generation *** TUCG process will consist of two parallel gasifiers,operated on different agents,making the component parts of UCG and coal-to-(any product)(CtX)tightly linked and interdependent,but reducing both cost and ***-CtX offers a lower capital investment to conventional underground mining and surface gasification due to the removal of the surface gasifier and coal-mine *** gas clean-up systems will remove undesirable components from each gasifier and blend the cleaned syngas for H2:CO ratio control and provide implementation of carbon capture and *** study has minimized the complexity and optimized the process flow to provide own-use electricity and about 4000 barrels/day equivalent fuels at a capital cost estimate(2017)of

关键词： underground coal gasification Fischer-Tropsch coal to liquids gas to liquids CCS UCG FT LNG CtX economic study South Africa

The effect of particle size on the pollution reduction potential of a South African coal-derived low-smoke fuel

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能源地球科学(英文) 2020年第3期1卷 165-173页

作者： Lungile Sumbane-Prinsloo John Bunt Ratale Matjie Stuart Piketh Hein Neomagus frans waanders Centre of Excellence in Carbon-based Fuels Faculty of EngineeringNorth West UniversityPotchefstroom2520South Africa Climate Research Group School of Geo-and Spatial ScienceNorth West UniversityPotchefstroom2520South Africa

The coal combustion in cast-iron stoves leads to health hazards and air *** this study the CO,SO2,NOx,PM and VOC emission concentrations were measured whilst combusting four fuel particle sizes(15,20,30,and 40 mm)as well as a composite of the sizes(all pre-devolatilized at a temperature of 550C)in a cast-iron *** results were compared to their raw coal analogues to evaluate the emission performance of each fuel *** factors for NOx and SO2 were found to depend on the fuel nitrogen and sulphur contents in the coal and the combustion conditions used during *** PM,SO2 and VOC emissions show a strong dependence on the ash percentage and volatile matter yields,which both increased with increasing particle *** addition,the PM,SO2 and VOC missions were found to only depend on particle size on a mechanistic *** VOCs and PM emission factors are inversely correlated with particle *** results from this study offer insight into the combustion environment in the Falkirk Union No 7 cast-iron stove as well as how this environment applies to low smoke *** work contributes to the emission and performance inventories from South African domestic coal combustion in this stove used in informal settlements.

关键词： Coal combustion Low-smoke fuel Emissions Particle size Cast-iron stove

The influence of particle size on the thermal performance of coal and its derived char in a Union stove

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Energy Geoscience 2021年第2期2卷 148-159页

作者： Lungile Sumbane-Prinsloo John Bunt Stuart Piketh Hein Neomagus frans waanders Ratale Matjie Centre of Excellence in Carbon-based Fuels Faculty of EngineeringNorth West UniversityPotchefstroom2520South Africa Climate Research Group School of Geo-and Spatial ScienceNorth West UniversityPotchefstroom2520South Africa

For low-income communities in South Africa,coal is the most common solid fuel which is burnt in a variety of devices,including imbaulas and cast-iron *** present work was conducted with the aim of determining the effect of the fuel particle size on the performance of coal,typically sourced in low-income households in townships in South Africa,and to subsequently compare the performance with a feed char of a common cast iron *** fuel particle sizes of 15,20,30,and 40 mm,as well as a composite of the sizes were tested at 550C,against their untreated coal analogues to evaluate the thermal performance of each *** thermal performance assessment metrics are ignition time,water boiling time,heat transfer and combustion efficiencies,while CO and CO_(2)emissions were measured for the calculations of CO/CO_(2)*** times were found to decrease from coals to chars and to decrease with increasing particle *** effects of fuel type on the water boiling time were only observed in the later stages of the burn cycle,with the char boiling a 2 L batch of water in an average 24 min,while the coals reported an average boiling time of 20 *** transfer efficiencies showed no significant variation with fuel type or particle size,with the average efficiency for the coals and that of the chars being around 66%.The fuels’performance was better gauged by the combustion efficiency,which was found to improve marginally from the coal fuels to the chars,and to increase with increasing particle *** from this testwork could contribute to the performance inventories from the combustion of domestic coal mined in South Africa in a typical cast iron stove which is used in informal settlements.

关键词： Coal and its derived char combustion Heterogeneous testing protocol Efficiency Particle size Cast-iron stove

不同pH值硫酸铁溶液中碳酸盐岩型黄铜矿的浸出机理

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Transactions of Nonferrous Metals Society of China 2021年第7期31卷 2139-2152页

作者： Kolela J NYEMBWE Elvis FOSSO-KANKEU frans waanders Martin MKANDAWIRE Water Pollution Monitoring and Remediation Initiatives Research Group School of Chemical and Minerals EngineeringFaculty of EngineeringNorth-West UniversitySouth Africa Department of Chemistry School of Science and TechnologyCape Breton UniversityCanada

在pH值0.5~2.5、温度25℃和时间12 h的条件下,研究碳酸盐岩型黄铜矿在H_(2)SO_(4)−Fe_(2)(SO_(4))_(3)−FeSO_(4)−H_(2)O体系中的溶解行为。实验所用的颗粒粒度为53~75μm。在所有pH条件下,Cu的回收率均低于15%。浸出渣的XRD、SEM−EDS和光学显微镜(OM)分析结果表明,溶解过程中形成了中间相。pH为0.5和1.0时的中间相分别是Cu_(3.39)Fe_(0.61)S_(4)和Cu_(2)S,而pH值为1.5和1.8时的主要矿物为Cu_(5)FeS_(4)。热力学模拟预测产物的生成顺序为CuFeS_(2)→Cu_(5)FeS_(4)→Cu_(2)S→CuS。Cu_(5)FeS_(4) and Cu_(2)S为可溶性中间相,而CuS和Cu_(3.39)Fe_(0.61)S_(4)是难溶中间相,在整个溶解过程中不断积累。所得结果表明,CuFeS_(2)浸出过程中CuS和Cu_(3.39)Fe_(0.61)S_(4)的生成有助于形成钝化膜。

关键词：黄铜矿碳酸岩化学浸出浸出机理中间相热力学行为

Environmental assessment and nano-mineralogical characterization of coal,overburden and sediment from Indian coal mining acid drainage

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地学前缘：英文版 2017年第6期8卷 1285-1297页

作者： Madhulika Dutta Jyotilima Saikia Silvio R.Taffarel frans B.waanders Diego de Medeiros Cesar M.N.L.Cutruneo Luis F.O.Silva Binoy K.Saikia Department of Chemistry CNB CollegeBokakhat785612AssamIndia Polymer Petroleum and Coal Chemistry Group Materials Science and Technology DivisionCSIR-North East Institute of Science&TechnologyJorhat785006India School of Applied Sciences Department of ChemistryUniversity of Science&TechnologyMeghalayaIndia Academy of Scientific Innovative Research CSIR-NEIST CampusJorhat785006India Laboratory of Environmental Researches and Nanotechnology Development Centro Universitario La SalleMestrado em Avaliacao de Impactos Ambientais em MineracaoVictor Barreto2288 Centro92010-000CanoasRSBrazil School of Chemical and Minerals Engineering North West University(Potchefstroom Campus)Potchefstroom2531South Africa Research Group in Environmental Management and Sustainability Faculty of Environmental SciencesUniversidad De La CostaCalle 58#55-66080002BarranquillaAtla nticoColombia Universidade do Vale do Rio dos Sinos.Av.Unisinos 950 Cristo Rei 90510030Sao LeopoldoRSBrazil

The deterioration of environmental conditions is the major contributory factor to poor health and quality of life that hinders sustainable development in any *** mining is one of the major industries that contribute to the economy of a country but it also impacts the *** chemical parameters of the coal,overburden,soil and sediments along with the coal mine drainage(CMD)were investigated in order to understand the overall environmental impact from high sulphur coal mining at northeastern coalfield(India).It was found that the total sulphur content of the coal is noticeably high compared to the overburden(OB)and *** volatile matter of the coal is sufficiently high against the high ash content of the soil and *** water samples have a High Electrical Conductivity(EC)and high Total Dissolve Solid(TDS).Lower values of pH,indicate the dissolution of minerals present in the coal as well as other minerals in the mine rejects/*** chemical and nano-mineralogical composition of coal,soil and overburden samples was studied using a High Resolution-Transmission Electron Microscopy(HR-TEM),Energy Dispersive Spectroscopy(EDS),Selected-Area Diffraction(SAED),Field Emission-Scanning Electron Microscopy(FE-SEM)/EDS,X-ray diffraction(XRD),Fourier Transform Infrared Spectroscopy(FTIR),Raman and Ion-Chromatographic analysis,and Mossbauer *** different geochemical analysis it has been found that the mine water sample from Ledo colliery has the lowest pH value of 3.30,Tirap colliery samples have the highest electrical conductivity value of5.40 ms cm^(-1)Both Ledo and Tirap coals have total sulphur contents within the range 3-3.50%.The coal mine water from Tirap colliery(TW-15 B)has high values of Mg^(2+)(450 ppm),and Br^-(227.17 ppm).XRD analysis revealed the presence of minerals including quartz and hematite in the *** analysis of coal mine overburden(OB)indicates the presence both of pyrite and marcasite which was also

关键词： Coal mine drainage Environmental assessment Indian coal Chemical analysis Nano-mineralogy Advance characterization