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By S. S. Indi, D. Santhiya, S. Subramanian, K. A. Natarajan

The interaction of sphalerite- and galena-adapted Bacillus polymyxa (B. polymyxa) cells with sphalerite and galena has been investigated through adsorption, electrokinetic and flotation studies. The amount of sphalerite-adapted cells adsorbed onto sphalerite and galena is found to decrease with increase in pH. On the other hand, the adsorption density of galena-adapted cells onto galena shows a feeble maximum around pH 8, and the amount adsorbed is marginally higher in the pH range of 8 . 11.5. In the case of sphalerite the amount adsorbed is higher in the pH range of 5 to 7. The adsorption density of both the adapted cells is higher for galena vis-à-vis sphalerite. Electrokinetic studies indicate significant surface chemical changes on the chosen sulphide minerals and the bacterial cells, consequent to microbe-mineral interactions. Selective flotation tests on a synthetic mixture of galena and sphalerite confirm that sphalerite could be preferentially floated from galena, using galena-adapted cells, but not with the sphalerite-adapted cells. The cells adapted to galena assay a higher polysaccharide content and are more hydrophilic, while the sphalerite-adapted cells have a higher protein content and possess greater hydrophobicity. Transmission electron microscopic studies have provided evidence in support of the differences between the cell surface characteristics of sphaleriteand galena-adapted cells. Possible mechanisms of interaction between the minerals and the bacterial cells are discussed.

Jan 1, 2003

By Arkady Senchenko, Sergey Rybkin, Svetlana Lagutina, Alexander Aksenov

"The application of autoclave leaching technology for sulfide concentrates containing base and precious metals is spreading nowadays. In the process of concentrate leaching silver accumulates in the forms of jarosite compounds, transforms into passive chemical state and is mostly found in solid phase. Effective technology development for silver recovery from solid phase of concentrate autoclave leaching raises the necessity for comprehensive research of silver forms of occurrence and their properties in this product. The possible form of silver presence in solid phase of concentrate from autoclave leaching is argentojarosite. This article is about the study of physical and chemical properties and structure of synthetic argentojarosite - AgFe3(SO4)2(OH)6. A method of argentojarosite synthesis has been developed under conditions simulating the process of autoclave leaching of sulfide concentrate, and includes silver dissolution in the form of Ag2SO4, Fe3+ sulfate hydrolysis, AgFe3(SO4)2(OH)6 build-up. X-ray data of synthesized argentojarosite completely correspond to those of natural mineral. The structural formula of this complex compound has been studied and confirmed. The chemical properties of synthetic argentojarosite, its solubility in acids and alkalis have been investigated. Phase changes when heating argentojarosite with the build-up of iron oxide and silver sulfate stop at the temperature equal to 650 ºC. Based on the results received the technological solutions for solid phase of autoclave leaching of concentrate have been developed with silver recovery of 95-98%."

Jan 1, 2014

By Braulio Fernández, Gonzalo Montes-Atenas

The mechanisms taking place during the leaching of chalcopyrite when it is in contact with other sulphide minerals, particularly pyrite, is still a matter not fully solved. The GalvanoxTM process has been suggested as a technical solution to extract copper from chalcopyrite at commercial level inhibiting passivation phenomena widely reported in the field of hydrometallurgy. Although there are some rules of thumb to implement the process in fully flooded stirred conditions such as the optimum pyrite/chalcopyrite mass ratio should range between 2 and 4, among others; not many research studies have been focused on studying the effect of the surface contact area between chalcopyrite and pyrite to reach best copper extraction conditions. The aim of this research work is to determine the effect of the mass and surface area ratio between the minerals and the surface area of each of the mineral species effectively exposed to the leaching solution. Different particle size distributions of pure pyrite and chalcopyrite were contacted in a small column and subjected to leach tests using sulphuric acid in concentrations close those used in industrial leaching processes. The mass and surface area ratios which optimize the extraction of copper were obtained. It was found the best leaching conditions were attained when reducing the particle size distribution of pyrite regardless the particle size distribution of chalcopyrite. Further analysis concerning the impact of this conclusions on large scale operations is presented and discussed.

Jan 1, 2014

By Prasad Kopparthi, Narasimha Mangadoddy, Balraju Vadlakonda, A. K. Mukhurjee

"Column flotation (CF) is widely using equipment in mineral processing since many years. ERT technique facilitates non-invasive and nonintrusive visualization of different parameters in a column flotation. The hydrodynamic investigation of two-phase and three-phase are studied using electrical resistance tomography (ERT) coupled with pressure transducers in laboratory column flotation. Bubble size distribution, bubble rise velocity and gas and solids hold-up hydrodynamic parameters are extensively used for column flotation design and performance evaluation. The effect of superficial gas velocity, feed flow rate and slurry height in the column on mean gas holdup and its radial distribution has been analyzed for both two-phase and three phase flows. Influence of solid particles on gas hold-up and its complete elucidation of dispersion in the column are assessed. Experimental results show ERT coupled with PT is suitable as an online monitoring tool to provide useful information on the hydrodynamic parameters of the column flotation. The tomography images, which were generated using a modified sensitivity back projection algorithm, were employed to explore the parameter study in two phase flow in column flotation.Furthermore, the results also indicate that ERT is a very powerful tool for diagnosing the `inside' flow behaviour of gas-liquid two-phase and gas–liquid–solid three-phase flow in columns operating for a wide range of flow regimes.INTRODUCTIONColumn flotation is being widely used in mineral processing industries in last few decades. There has been a lot of attention in understanding the various mechanisms that take place during operation. Due to many reasons column flotation has been found to yield better performance than conventional flotation cells, particularly with fine particles (Honaker and Mohanty, 1996). Due to complex flow behavior in nature, the performance of column flotation influenced by on flow characteristics of the process, (Jena et al., 2008). Previously basic research is carried out to evaluate the effect of the hydrodynamic parameters on the performance of column flotation (Finch and Dobby, 1991)."

Jan 1, 2018

By l. Bokányi

The Tóth adsorption isotherm-model was derived and has been widely used for the inhomogeneous solid surfaces. The three-parameter isotherm incorporates the effect of the interaction between the adsorbed substances as well. All classic isotherms can be clearly derived from this one. Bio sorption is the sequestering of dissolved components, i.e. metals from aqueous environment by living or dead biomass. The mechanism of the bio sorption is rather complex and predominantly refers to the affinity of the chemical functional groups: acetoamido groups of chitin, structural polysaccharides, amino and phosphate groups in nucleic acids, amino, amido sulfhydryl and carboxyl groups in proteins, hydroxyls in polysaccharides, sulphates, etc. towards the soluted substances, i.e. heavy metal ions. The physisorption, as well as the micro precipitation also play a role in the bio sorption mechanism. The description of such a complex process can be done by a model reflecting this complexity. According to our experimental results obtained using algae and immobilised algae for the sorption of heavy metal cations, the most appropriate model for such a description is the Tóth-isotherm, the parameters of which can be interpreted. Flotation process is also a very complex one, the overall result of which depends on the partial results of many micro processes and parameters. The particle interaction which very often takes place in the flotation systems makes the phenomenon even more complex. The flotation kinetic model with particle interaction was already introduced by author in 1994 and further developed in 2000. In this paper based on the experimental results obtained with metallic particles in case of recycling flotation the applicability of the Tóth-equation as an alternative flotation kinetic model for the systems with particle interaction is proved. The applicability of Tóth-model in mineral processing demonstrates again its universal character and the great talent of the late József Tóth, great Hungarian chemist. Keywords : Toth isotherm, biosorption, Langmuir, Freundlich

Sep 1, 2012

By Komar Kawatra, Joseph Halt

"Bentonite clay has been the traditional binder for iron ore pellets. However, bentonite increases pellets’ silica contents and is expensive. Researchers have proposed lowering bentonite doses by mixing it with other common binders. These mixtures may only be successful if the fundamental bonding mechanisms are understood. For example, what happens when bentonite (physical bonding) is mixed with fly-ash (chemical bonding)? What happens when bentonite is mixed with cornstarch (physical bonding)? In this paper, experiments are described where bentonite was mixed with various ratios of cornstarch and fly-ash, and pellets were agglomerated using 0.66 % w/w binder. Ca(OH)2 and CaCl2 were added as activator and accelerator, respectively, to the bentonite-fly ash mixture. Curves of pellet dry strength vs. bentonite-starch ratio were linear, suggesting the physical-physical bonding mechanisms were compatible - acceptable strengths (> 22 N) were produced at all bentonite-to-starch ratios. This was contrary to bentonite-fly ash mixtures, which displayed dry strength curves with a noticeable minimum due to competing binding mechanisms. Bentonite alone and fly ash alone produced acceptable strengths (> 22 N), but their mixtures resulted in weak pellets. Due to the positive results using cornstarch (CS) binders, the effects of CS solubility in water were investigated using two CS with high and low solubility (60 and 7.5 %). CS was premixed with bentonite at various ratios (0, 20, 40, 60, 80, 100 %). Pellets were agglomerated using 0.66 % w/w binder. The dry strength of pellets ranged from 50-300 N using the high solubility CS mixtures, and from 50-85 N using the low solubility CS mixtures. Fired strengths exceeded 2200 N/pellet at all bentonite-cornstarch ratios. This research showed that cornstarch solubility is an important factor in determining its effectiveness as a binder for iron ore concentrates, but significant work is still necessary before it can be used as a bentonite replacement."

Jan 1, 2014

By Francis Pitard

"The optimization of metallurgical processes requires an in-depth understanding of the heterogeneity carried by any constituent of interest. It emphasizes that knowledge of the Theory of Sampling (TOS) is the necessary step to ensure that valuable and valid research programs, pilot plants, feasibility studies, plant design and plant operations have been set on solid foundations. Too many publications today are solely based on the properties of the sample, with no mention of how this sample relates to anything in the environment where it was collected. Unfortunately sampling is an error-generating process that leaves no apparent tracks of its shortcomings. Indeed, it is easier to track down analytical errors than sampling errors. Consequently, bad sampling practices plague the scientific community and the industry and are responsible for severe money losses, unsatisfactory science and processing, and sometimes litigation. A point-by-point strategy is presented addressing sampling problems in early stages of a project. Sampling system requirements for metallurgical accounting and process control are listed. The use of Chronostatistics is suggested to determine if sampling systems are performing satisfactorily and to identify the various types of process variability that may not be easily detected by a conventional inspection of available chronological data. This strategy will help engineering firms, manufacturers, managers and supervisors to provide, install, use and maintain key sampling systems located at very important points in a process. Equipped with the appropriate sampling and statistical tools it becomes easier to minimize reconciliation problems with the mine, with suppliers and with clients. Contrary to the beliefs of many people, good sampling systems are not expensive because in the long run they help to reduce hidden cost and better regulate plant productivity; they most certainly minimize the number of unnecessary meetings looking for solutions where there are none. The suggested strategy will help specialists to extract maximum information from the available data, as large investments and crucial decisions depend on it."

Jan 1, 2014

By Hermann Wotruba, Günther Petzold, Fabian Riedel

"Increased mechanisation in underground stoping operations results in higher waste percentages in the run of mine. A new method of reducing waste is optical sorting. Optical sorters have low maintenance costs and can be installed underground. Rejected waste can be backfilled directly without having to be hoisted, therefore increasing the shaft capacity for a more valuable product.Pre-Concentration by Optical SortingA series of tests with an optical sorter at the laboratories of the Mineral Processing Department of the RWTH Aachen have shown that it is technically possible to sort almost any kind of ROM which has even slight differences in colour (Platinum Reef, Gold Reef, Kimberlites, Industrial Minerals, Aggregates, Coal, etc.).By employing optical sorters prior to conventional sorting plants, it is possible to reduce the amount of waste to be processed. Figure one shows test results of ore which is quite similar in colour to the waste (grey). With increasing waste in the feed, the recovery decreases according to the graph. In figure two, the colour ratio parameter of the sorter was changed with a similar waste percentage in the feed. With increasing loss of ore, a cleaner product can be achieved. Before designing a sorting plant, throughput tests are carried out. Throughputs vary depending on the size range. Sorters have a limit of about 250mm top size. In this upper size range, throughputs of 150t/h can be achieved."

Jan 1, 2003

By R. C. Miranda

This paper intends to demonstrate the applicability of tools for advanced process control and online particle size image analysis in crushing and autogenous grinding circuits. In a crushing plant, cameras are installed in the conveyor belts of the circuit products. The vision system continuously processes the acquired images and thus obtains the variation of the size distribution curve. From these measurements, the advanced control system can operate, for example, at the opening of the crusher, in order to keep the P80 in the desired range. In addition, through the power information and level of the crusher's chamber, it is possible to increase the capacity of the crushing circuit. If the crusher is not equipped with an automatic opening adjustment, a warning may be issued to the operator to provide this setting manually. In mineral processes that use autogenous and semi-autogenous grinding for fragmentation, obtaining online F80 through the vision system allows for manipulating the parameters of rotation speed and solids concentration, through which the amount of material at the critical particle size that is produced can be controlled. In addition, the noise produced in the mill can be measured and controlled. Thus, it is possible to prevent breaches and to optimise the mill capacity for grinding. Image analysis combined with an expert system that translates this information and acts to seek the most appropriate particle size distribution, brings greater stability to the process optimising the capacity of the equipment, which allows for significant gains in production.

Sep 1, 2012

By Kari Niiranen, Andreas Fredriksson

LKAB (Luossavaara-Kiirunavaara AB) is operating iron ore mines, concentration plants and pelletizing plants in Northern Sweden. Geometallurgy, which combines geological and metallurgical information is not a new way of thinking at LKAB, but rather a revised and updated version of an old working process. A project called "Silica in the Mine" which started in 2007, was an important reason to set a new focus at the geometallurgy. The target of the project was to develop a simplified method in laboratory scale to predict SiO2 grade in the magnetite concentrate in Kiruna and further predict the physical properties of the crude ore with respect to processing characteristics. The connection between mineralogy and products properties have started to be even more vital and necessary to examine due to the future exploiting new iron ore deposits. Geometallurgy at LKAB can be described as a mental and strategic framework where the Research and Development department (R&D), and others within the organization of LKAB, aims towards the connection of the minerals-production-products. It could in its basics be called "research & development", but it must be clarified that changes have been made, mainly due to the development on the instrumental analysis side. LKAB’s idea is to work quite broad, with internal educations, an active working process in ongoing projects, together with external parties (such as universities), with several PhD-projects and an upgrading on the instrumental side at the LKAB Research & Development department. This paper is a summary about the concept Geometallurgy at LKAB and some of the actions within its framework.

Jan 1, 2014

By Fatemeh Saeidi, Malcolm S. Powell, Mohsen Yahyaei

In order to deal with the problems of existing comminution models a new approach towards the development of mechanistic models has been made so as to better understand the physics of milling processes and environments. Despite enormous improvement in this field a comprehensive study of rock breakage characterisation, appropriate for use in these types of models, is still scarce. This paper reviews the existing models of comminution according to ore characterisation techniques and parameters. The authors have looked into the existing testing methods and their applied mechanisms of breakage, using standard test results available at the JKMRC. The study includes classifying testing devices such as the drop weight tester, rotary breakage tester, slow compression, and piston and die based on the few major fundamental mechanisms of breakage that are experienced by rocks in the breakage process. The paper compares the range of particle size and energy utilisation, applied strain rates and loading mechanisms for the equipment. The product size distributions from the various equipment is compared for equivalent input energies, various loading rates but the same level of energy intensity, a broad range of energy including low energy utilisation and fines generation rate for equivalent specific energy input. The results clearly show that the outcomes and conclusions on competence and energy for breakage are a function of the test method that is applied. In ongoing work, it is proposed to investigate common tests that can be applied to characterising ores in a manner suited to modelling a range of comminution devices.

Jan 1, 2014

By Vladimir Vigdergauz, Sergey Kondratiev

The paper reviews the existing criteria of the formation of particle-bubble aggregates during flotation. It is shown that predictions obtained by these criteria do not completely fit to the interaction between mineral particles and air bubbles. Experimental results of the studies into the influence exerted by molecular forms of collectors on the particle-bubble interaction are reported. Rate of dry spot expansion on the surface of pyrite with various combinations of chemically and physically adsorbed xanthate are examined. It is shown that molecular forms of collectors accelerate the rate of dry spot expansion on the mineral surface after the local rupture of the water film between particle and air bubble. The authors come to a conclusion that the molecular forms of collectors remove water from the interlayer between mineral particle and air bubble during their contact. Similarities of the proposed mechanism with the action of ion-molecular associates of fatty acids and amines are discussed. Reagents with high surface pressure and rate of spreading at the water-bubble interface are required for the effective interfacial dewatering. It is concluded that the value of surface pressure can serve as the criterion for efficiency of physically adsorbed reagents. The low surface pressure indicates weak collecting ability but high selectivity of the collector. Therefore, the presence of the molecular forms of collectors in the sorption layer is the necessary condition for formation of particle-bubble aggregates, and comparison of the surface tensions of collectors could be recommended as the estimation criterion of their flotation activity and selectivity.

Jan 1, 2014

By K. A. Natarajan

Involvement of various indigenous microorganisms in extracellular and intracellular iron oxide formation is a convincing index for iron ore biogenesis. Biomineralization of various iron oxides such as hematite, magnetite, goethite and limonite with the participation of aerobic and anaerobic microorganisms is well established. Various aerobic and anaerobic bacteria such as Gallionella, Leptothrix, Acidithiobacillus, Thermoplasmales, Pseudomonas, Bacillus spp and Shewanella putrefaciens, which are implicated in the formation of higher and lower oxides of iron have been isolated from different iron ore deposits. Diversity of microbial life in iron ore deposits can be put to beneficial use such as selective removal of undesirable constituents such as silica, alumina, clays, phosphorous and calcite and also to bring about environmental detoxification. Role of microorganisms such as Paenibacillus polymyxa, Bacillus subtilis, Yeasts and a sulfate reducing anaerobe in the biobeneficiation of hematite is illustrated. Surface chemical changes brought about by bacteria - iron ore mineral interactions are discussed with respect to hydrophobcity, adsorption isotherms, zeta potential data and bioreagents generation. Bacterial adaptation to minerals such as hematite, quartz, alumina, calcite, apatite and clays results in secretion of mineral ? specific biosurfactants such as proteins and polysaccharides. Such bioreagents can be used as selective collectors, dispersants and flocculants in iron ore beneficiation. Research results are highlighted to demonstrate silica, alumina, phosphate, calcite and clay removal from hematite. Environmental friendliness of such biobeneficiation processes is demonstrated with respect to biodegradation of toxic amine collectors, utility of ?in situ? organisms in enhancing settlement of fines in tailing dams and water harvesting. Keywords: bio-mineralization, bio-beneficiation, bio-remediation, Gallionella, Leptothrix

Sep 1, 2012

By Rod Hocking, Nenad Djordjevic, Randolph Pax

"Semi Autogenous (SAG) mills exhibit complex interactions between the competing processes occurring inside them. Traditional practice is to measure the operation of the SAG mill at an operating point in terms of its load, power draw, steel load, ore throughput rate, water addition rate and more recently the feed size distribution. However significant departures of operating conditions can occur due to changes, for example, in ore hardness, the quest for higher throughputs and mill internal geometry.Fundamental to SAG mill operation are the internal processes that ensure that a given ore throughput and discharge grind size are obtained and maintained. These processes can be measured using non-contact acoustic emissions from the SAG mills which utilise the information rich noise that is generated by the grinding, flow and charge movement inside a mill.Non-contact acoustic in-mill measurements can be used for the validation of discrete element modelling (DEM). The approach being reported in this paper is to model the individual physical processes and then to simulated the assemblage of a physical mill."

Jan 1, 2003

By Lina Chica, Arturo Barrientos, O. Bustamante

Hydrocyclone is a device commonly used in mineral processing industry. Underflow control plays a fundamental role in hydrocyclone operation. This affirmation supports the fact that hydrocyclone underflow has effect in some aspects of separation performance like capacity, split ratio, cut size and bypass. Hydrocyclone operation state is associated to underflow characteristics: air core formation and discharge shape. Many studies attempt to understand size separation phenomenon and the discharge influence but none of them has taken an energy point of view. This work presents the results of a mechanical energy dissipation for hydrocyclone operation from a mechanical energy balance. The experimental results related to Newtonian suspensions show that underflow energy dissipation does not control the operation because this magnitude is small compared to interior energy dissipation. However, discharge energy dissipation provides enough information to describe underflow conditions and its influence in separation conditions. In the modelling non dimensional parameters have been considered for hydrodynamic description and for geometrical and operation hydrocyclone characteristics. Energy dissipation from the continua media approximation results into a relevant concept to understand the hydrocyclone performance and improve industrial installations.

Jan 1, 2014

By Scott C. Brown, Brij M. Moudgil, Ivan U. Vakarelski

The manipulation of the apparent hydrophobicity of particlute surfaces is necessary to achieve optimal selectivity in flotation processes. Previously a number of works have investigated the role of microscale surface and particulate morphologies on chemically modified substrates. These works have suggested that microscale surface asperities lead to an increase in flotation efficiency by assisting in the rupture of wetting films. Yet, in mineral processing the presence of surface asperities may lead to a reduction in flotation. The reason for this may-in part-be due to the presence of nanoscale irregularities at the interface. In this work, it is proposed that the presence of roughness at the nanoscale may have a dominant impact on the apparent hydrophobicity of mineral surfaces during flotation. It is suggested that as inter-asperity seperation distances are reduced capillary effects are enhanced for high energy mineral surfaces leading to the formation of liquid domains, which adversely impact hydrophobicity. In addition, as these distances approach the surfactant headgroup size obstruction of surfactant self-assembly process may occur, thereby further limiting flotation.

Jan 1, 2003

By J. Gebhardt, D. McBride, M. Cross, S. Gilbert

Heap leaching of ores containing chalcopyrite offers a low cost option to treat low grade complex copper sulfide ore bodies. However, the slow leach kinetics of chalcopyrite at ambient conditions typically results in unacceptably low recoveries. As the mineralogy of new ore deposits becomes more complex and the effects of gangue chemistry exert a greater influence on copper sulfide leach behavior, the control of leach reaction chemistry becomes more critical. Computational fluid dynamics (CFD) technology has been useful in the capture of multi-phase interactions and provides a path to simulate complex fluid flow, gas and liquid phases, through the heap, along with species transport. Coupling the flow models with the reactive mineral dissolution, and the sometimes competing aqueous chemical and solid-liquid reactions, yields a comprehensive model of the heap leach process. The leach kinetics of chalcopyrite dissolution in heap conditions is examined, and the incorporation of chalcopyrite leach kinetics in the CFD model is described. The application of the model to investigate optimization of the heap is discussed.

Jan 1, 2014

By David G. Hulbert, Daniël J. Oosthuizen, Bernard Muller, Daniël de V. van der Spuy

"OVERVIEWExpert Online is a software system that aims to mimic an informed expert on a minerals processing plant. The primary objective of Expert Online is to provide operators with effective training and on-the-job assistance. Training will mostly be done off-line (e.g. using simulators of the plant), while on-the-job assistance will help the operator during normal operation to run the plant in an effective manner. Although Expert Online focuses on the operator, it is expected to also be of value to other plant personnel, including supervisors and plant managers.Expert Online will make use of novel artificial intelligence technology (developed by MINTEK) known as the Interpreting Expert System (IES). Previously the IES was only able to explain the actions taken by the controller. Expert Online will extend this functionality to also take the process dynamics into account.Expert Online is being developed by a South African consortium comprising MINTEK (focusing on the research and development of the system as a whole), Lonmin (globally one of the biggest platinum producers, with plants suitable to test Expert Online on) and the University of Natal (academic partner, providing consultation and focusing on complex process modelling). The initial application of Expert Online will be on milling- and flotation plants.This paper discusses the structural design of Expert Online for implementation on the latest version of MINTEK’s open control platform, PlantStar, as well as several advances and additions since the previous implementations of the Interpreting Expert System."

Jan 1, 2003

By Anatoly N. Vinogradov, Vyacheslav A. Tsukerman

The North-West Russia for 70 years is one the main producers of Cu, Ni, Co, Al, P, REE, Zr, Ti, Ta, Nb, Fe ores and other minerals in the Europe. The largest mining companies locates in the Murmansk region, and they extracts about 100 mln. tons of ores and damps up to 250 mln. tons of waste annually. Nevertheless an environmental situation in the region is stable due to rational management and treatment of wastes on a base of the Noosphere Concept for Nature-using suggested by Vladimir Vernadsky. The Concept was performed practically in the Fersman’ scheme of “non-waste mining and metallurgical complex”, published in the monograph “Minerals of the Kola Peninsula: current status – analyses – prognoses” (1941) and served till now as a sort of “Bible” for industry managers lightening a strategy for an industrial “trophic chain”. The recent status of this scheme is shown on the picture below, and one can see that our concept is coincide with modern ideology known as the “Industrial Ecology”. Moving along this mainstream in the Kola Peninsula since 1929, when the first mining company “Apatit” was established, we provided the water close circuit in mineral dressing plants, hydrometallurgical treatment of slag and tailings, productions of building materials and adsorbents of wastes. The innovation set of technologies designed by the Kola Science Centre allow recently to involve tailing damps in re-exploitation as the technogenic deposits of valuable raw materials for fertilizers, tanning and cleaning agents, pigments, concretes and etc.

Jan 1, 2003

By N. T. Beukes, W. Banda

Recovery of Co from slag is a recent advancement in the extractive metallurgy of nonferrous metals. In this study a DC arc technology at laboratory scale has been applied to investigate the selective recovery of Co from slag, under three different flux types with an emphasis on influencing the activity of FeOx, SiO2 and CoO in the slag. It is known that reduction of slag by carbon is only up to a certain level after which, the recovery will depend on the chemistry of the slag, hence the need to modify the slag chemistry. Two power settings were employed to induce higher temperatures and aggressive agitation. The results were interpreted by comparing how much Co and Fe was in the slag and alloy. TiO2 reduced the amount of Fe in the product alloy compared to when CaO and CaF2 were used. The change in power did not seem to have had a major effect on the recovery although the amount of material lost to flue dust was more at a higher power rate.

Jan 1, 2003