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By C. Carrasco

"Over the last 30 years the average grade of mined ore bodies has significantly decreased while the proportion of waste removal has in many cases more than doubled. This has been identified as prime reason of a major increase in energy consumption and decrease in productivity across mining operation. Metal coarse preconcentration of ROM feed grades by size rejects low grade gangue/waste material in the size range of 10-100 mm prior to grinding, typically before primary crushing. This relies on propensity of metal to preferentially deport in the fine size fractions after breakage. Metal preconcentration by size has the potential to increase energy efficiency and therefore improve mining productivity on unit of metal basis. Results of an extensive belt cut sampling campaign conducted at a major Australian Au-Cu mine operation show that for some samples between 90% of Au and 80% of Cu is in 40% of the mass at -50 mm fraction. This indicates that low grade coarse material can be removed from the circuit, doubling feed grade at half of the tonnage and therefore improve energy efficiency per unit metal produced. This response, however presents significant variability in the same order as other processing attributes such as impact hardness and flotation recovery. This has led to development of geometallurgical laboratory tests using blast hole chips and drill core facilitating mapping and population of coarse metal preconcentration signatures in long term resources and short term production models. Preferential Cu deportment by size at drilling scale can be recognised, however scales up factors are required to transform laboratory results to production responses. At 50 % of mass the drilling products underestimate the belt cut responses by 20-30 %. Bulk sampling campaign with blast hole and drill core samples spatially related was also conducted to investigate in more detail the difference between production scale and drilling scale preconcentration responses."

Jan 1, 2014

By S. Narra, M. Nelles, I. Eickhoff, S. Teitge

"The aim of the research is to develop a holistic process flow for the recycling of glass fibres from glass reinforced plastics (GRP) and carbon fibres from carbon fibre reinforced plastics (CFRP), wherein the dissolution of the fibre epoxy resin matrix, separation of fibre fractions and their renewed material use is intended. In clear distinction to the previous research and development projects, the aim here is to recycle complex composite structures such as dismantled/disused wind turbine rotor blades and end-of-life composite wastes. In the course of the study, mechanical, hydrothermal and thermal processes and their combined procedures will be developed. As the fibre length is a decisive quality criterion in the recycling of composite materials, the further focus of the study will be the development of upstream and downstream material processing, in which the fibres are retained in their original form. The evaluation of the recycled fibres obtained is based on the elemental composition, measurement and morphological evaluation of individual filaments by scanning electron microscope (SEM), micro tensile tests on single fibres and their comparison to virgin fibres. The resulting process water is analysed by gas chromatography and mass spectroscopy (GC-MS) and a potential recirculation is determined. In cooperation with companies from the composite processing industry as well as recycling companies, a return of the recycled fibres to the known manufacturing process will be examined and an energetic and economic evaluation of the overall process will be carried out. Ambitious aim of the study is to achieve an actual recycling instead of the present downcycling or the energetic utilization. INTRODUCTION As global warming increases, so does the awareness of consumption and production of energy. To counteract the effects of global warming, renewable energy has been increasingly used during the last two decades, not only in Germany, but worldwide. Both, hydropower and wind energy, hereby play a fundamental role. After the end of their useful life of 20 to 30 years, the wind turbines (WTs) are being dismantled. Due to their foundations and tower segments, their recycling rate hereby exceeds 90% by mass. So far, the resulting rotor blade waste played a minor role accounting for only 2 - 3 weight-% of the total plant. Rotor blades of modern wind turbines are made of glass and carbon fibers, which are embedded in an epoxy or polyester resin matrix, balsa wood, PU or PET foams as fillers as well as various paints and coatings. These wastes currently end up in waste incineration or are sold to non-European countries."

Jan 1, 2018

By Christopher Tucker, Marcello Veiga

Social issues are increasingly recognized as significant inhibitors to mineral development projects. Increasingly social risk is being recognized as a key factor determining the success of a mineral investment. Groups opposed to a mine for social or political reasons often use environmental impacts, real or perceived, to prevent mine development. These risk factors depend largely on cultural perceptions of mining activities and must be understood as such in order to be appropriately managed. A first step to addressing social issues is inclusive, transparent and meaningful engagement of stakeholders. This process allows stakeholders to understand what the other parties value in order to collectively establish a common currency for development and the creation of mutual value. Expanding the scope of benefits and values a mine can bring is of increasing importance to mining companies who typically consult outside specialists remote from the mine site and late in the development timeline for this purpose. Training technical staff, engineers and geologists, who make initial and ongoing contact with local interests, in a holistic approach to mine development is crucial to successful and economic mineral development projects. Further extending this conversation to the general public, media governments and non-governmental organizations is a necessary step in developing a meaningful discourse on the benefit of mining activities.

Jan 1, 2014

By L. G. Wang

The stability of foams and froth plays an important role in flotation, in which small amounts of relatively weak non-ionic surfactants (frothers) are used to produce air bubbles and foams. In the present work, factors affecting the stability of the foams produced in the presence of common frothers, such as n-pentanol, n-octanol, methyl isobutyl carbinol (MIBC), and polypropylene glycol (PPG), have been studied. We used the thin film pressure balance (TFPB) technique of Schelud-ko-Exerowa type to measure the equilibrium film thicknesses. The results were used to determine the contributions from the various surface forces to the disjoining pressures in the thin lamellae (foam) films formed between air bubbles. In addition, we used a model developed by Wang and Yoon (Colloids and Surfaces A: Physicochem. Eng. Aspects, 2006) to calculate the elasticities of the lamellae films at the critical thicknesses at which films rupture. The surface forces and elasticity da-ta were then compared with the foam stabilities in the presence of the various flotation frothers. It was found that foam stabilities are controlled by both film elasticity and surface forces, the relative contributions of which change with frother type and concentration. In general, surface forces play a more important role at relatively low frother concentrations, while elasticity plays a more important role at higher concentrations. At the frother additions usually employed in the mining industry, MIBC relies on surface forces while PPG-400 relies on film elasticity in producing stable foams. The former is capable of dampening the hydrophobic force, which is a major attractive force destabilizing lamellae films, while the latter is capable of reducing surface tensions at low concentrations.

Jan 1, 2014

By John O. Marsden

"Technology development and innovation has played a crucial role in the copper industry throughout history. The effective development and implementation of new technologies allows mankind to produce copper at progressively lower cost of production at a given feed grade and mineral type. This progress serves to counteract cost inflation/escalation over time and, depending on the magnitude of the cost benefit, allows ore cut off grades to be reduced thereby improving the availability, accessibility and utilization of resources. Two broad categories of technology development and innovation play a key role in this process: (i) incremental improvements and optimization of existing technology provide benefits in the near- to medium-term, and (ii) step change technologies provide value over the longer term. A key issue for potential developers and implementers of new step change technology is how to justify resource allocation and expenditures for such initiatives. This paper examines this issue with reference to specific case studies in the copper industry. INTRODUCTION AND BACKGROUND Technology development and innovation has played a crucial role in the commodity minerals industry throughout history, and none more important than the copper industry. As new, cost-efficient technologies are commercialized, the cost of production in real terms at a given ore feed grade and mineral type decreases. This progress enables ore cut off grades to be reduced allowing lower grade material to be processed economically, which in turn increases the availability and supply of the metal or mineral of interest. Cost inflation/escalation works in the opposite direction, squeezing margins for operations utilizing incumbent technology to process material from a given ore deposit. A prior review by the author considered the issue of technology development and sustainable competitive advantage. This review concluded that first movers and fast followers can achieve competitive advantage for periods of 10-15 years through effective deployment of new technologies (Marsden, 2004). A new, more comprehensive study and evaluation was completed in 2014. This paper presents a portion of the results from the 2014 study."

Jan 1, 2018

By B. Q. By

TiO2 is an ideal material for catalytic technology due to its unique properties. In this paper, Sm3+ doped TiO2 photo-catalyst was developed to improve the efficiency of TiO2 and to use the natural light as irradiation source, which was made from Titanium Tetrabutoxide and Samarium Oxide with the Sol-Gel process. The Sm3+-TiO2 photocatalyst was used to degrade reactive orange 4 (RO4) in Azo Dyes. The effects of solution pH, Sm3+ concentration and catalytic time on the degradation rate of RO4 were studied. The characteristics of the catalyst were analyzed with XRD and TEM. The experimental results show that the catalyst has high activity in the degradation of RO4. The Azo bonds of RO4 are active and easily broken by oxidation. The catalytic activity of the Sm3+ doped catalyst greatly depends on the pH of solution. The catalyst has high photo-catalytic activity at both neutral and alkaline conditions. The degradation mechanism of the Sm3+ doped TiO2 photo-catalyst was also discussed.

Jan 1, 2014

By N. Syna

The selection and preparation of activated carbon suitable for specific application can often involve exhaustive adsorbent preparation and testing. This work examined an emerging technique based on modelling the correlation of observed adsorption capacity to the carbon characteristics as a means of decoupling the roles of carbon textural and surface chemical properties. The insights to these specific roles are then used in tailor-making adsorbents and in establishing the optimal carbon properties for specific application. In this study, a series of activated carbons prepared from bagasse by physical and chemical techniques and commercially available carbons were used in developing the models. These carbons were tested for the adsorption of thiourea-gold (I) chloride complexes. Thiourea is an important alternative gold lixiviant with the potential to address current ecological and safety concerns in the extraction of gold. A four-component model, which correlated the adsorption gold capacity to carbon textural and surface chemical properties, was proposed. The model fit was assessed using multi-linear regression and a partial F-test. This was followed by goodness of fit test achieved through r2, adjusted?r2 and mean square error (MSE) values. The results suggest the adsorption of the gold-thiourea complex is strongly influenced by the internal surface area and pH of the carbon. Tailor-made activated carbon from bagasse showed adsorption gold capacities of up to 198 mgAu/g adsorbent, demonstrating the potential of bagasse as a precursor for gold adsorbents and of this empirical modelling approach in developing adsorbents for metal recovery.

Jan 1, 2014

By Maurício Torem, Gabriela Huaman, Antonio Merma

The purpose of this review paper is to succinctly present the most significant works related to Mineral Processing and Environmental Bioremediation and developed by the Mineral and Environmental Technology Group (METG) of the Materials Engineering Department of the Pontifical Catholic University of Rio de Janeiro (PUC-Rio). In mineral processing it was emphasized the use of the Rhodococcus opacus bacteria as a bioreagent in the bioflotation of some mineral samples (magnesite, calcite, hematite, quartz and apatite). The adsorption of the bacterial cells on the mineral surface can be due to specific and/or non-specific interactions, which will depend on several factors, as their surface charge and hydrophobic character. The zeta potential evaluation of the mineral particles before and after interaction with the R. opacus cells showed that the biomass modified the zeta potential profiles of the minerals, which confirm the adsorption of bacterial cells on the mineral surface. Moreover, the bacterial cells adsorbed caused a change in the mineral flotability which is related to a change in their hydrophobic character, thus, the mineral bioflotability was found to be dependent on the pH and the bacterial concentration. On the other hand, the environmental bioremetiation assessed the biosorption potential of three metal ions (lead, copper, and cobalt) by four different biomass Streptomyces lunalinharesii, Rhodococcus opacus, Rhodococcus ruber and coconut shell powder. For this purpose, biosorption process was characterized under different operating conditions such as initial pH and biosorbent dosage. The Freundlich and Langmuir isotherm models were applied to the equilibrium data obtained at different concentration.

Jan 1, 2014

By P. N. Mohan Das, K. Harikrishna Bhat

"The major ilmenite reserves are located in India at Chavara (CH), Manavalakurichi ( MK) and Chatrapur, Orissa (OR). India stands first in terms of ilmenite reserves, which are estimated to be 278 million tonnes out of which, 142 million tonnes are processable. Mineralo-chemical analysis shows that Chavara ilmenite is the most weathered one with about 60% TiO2 while Chatrapur is the least weathered with about 50% TiO2. Co-existence of ilmenite with pseudorutile, rutile and haematite is observed in substantially varying amounts in the three deposits. It is observed that the tropical weathering rather than the source rock difference has apparently played an important role in imparting major compositional and structural dissimilarities among ilmenites in different places.In processing of ilmenite through the Becher process, aeration rusting of pre-reduced ilmenite is found to be the rate limiting step thus, affecting the productivity of the process. Investigations have proved that the addition of some organic compounds such as glyoxal, sucrose etc., to the system accelerates the reaction to such an extent that the rusting time has been reduced to less than half.A new route of processing ilmenite for synthetic rutile has also been developed in which, ilmenite is carbothermally reduced and then processed through plasma route. The slag thus obtained is processed further to get high-grade synthetic rutile, metallic iron and high purity iron oxide. The process has been scaled up in a continuous moving bed plasma reactor. It is technologically and economically more viable where, all the iron values are recovered as salable byproducts. This paper describes the salient features of the technologies developed for the beneficiation of ilmenite to synthetic rutile."

Jan 1, 2003

By G. G. Xiong

Water-sealed cyclone is a new efficient equipment to use for grading,concentrating of slurry, it was researched and developed by the Kunming Metallurgy Research Institute in the 1980s , and ac-cessed to the 1990 national invention award and the national patent products (ZL02245313.X ). The equipment and technology are innovative, firstly, we design a set of micro-pressure (0.005~0.008MPa) water-sealed device, which eliminates the gas phase of three-phase of sol-id-liquid-gas of the traditional general hydrocyclone grading process, it only has solid and liquid phases. Secondly, the axial velocity envelope surface which is a factor of controlling the accuracy of grading changes to a wedge rotation; and the interface of upward flow to down flow changes from surface to the solid, it can improve grading accuracy. Thirdly, water-sealed box and catheter devices make the stilling which pass through the cyclone cone centrifugal force fields re-enter the pressure grading zone of catheter. The three innovations make water-sealed cyclone can reduce the loss of overflow and has less mud in stilling product. Because the excellent performance, the water-sealed cyclone has application in non-ferrous metals, ferrous metals, non-metallic and aluminum hydroxide industries for grading, desliming and concentrating since it has successfully developed.

Jan 1, 2014

By Jan J. Cilliers, Nicolas Barbian, Esther Ventura-Medina

"Froth structure and stability are known to play an important role in determining flotation recovery and selectivity. An industrial sampling campaign was performed to develop a clearer understanding of the effect of flotation variables on froth stability and the role played by the resulting stability on flotation performance.Froth stability was estimated as the fraction of bubbles bursting on the surface of the froth through image analysis and the solids loading on the bubbles at the top surface. It was generally found that high air flowrates resulted in a drop of froth stability showed by a drop in the fraction of air overflowing and a decrease in the solids loading and simultaneously produced low copper recoveries and low concentrate grades. Deep froths only allowed a small fraction of air to overflow and consequently produced low recoveries. An increase from a standard to high frother dosage did not result in a larger fraction of air overflowing, hence producing low recoveries. Likewise, low frother addition only allows low recoveries because the resulting unstable froth cannot support itself. Low aeration was found to be preferential as it allowed high particle loading, therefore high bubble stabilisation, and low gangue entrainment, resulting in the highest flotation performance.Additional laboratory tests were performed to introduce a new stability parameter and to give a clearer understanding of the effect of flotation variables on froth stability. The results confirmed some of the observations made on the plant."

Jan 1, 2003

By I. I. Beloglazov, G. A. Iusupov, A. Ju. Feoktistov

"The aim of this paper is to study the numerical modeling of the crushing process in a jaw crusher with complex motion jaws using Discrete Element Method (DEM). The main goals are to ensure the conformity of numerical simulation results to the experimental data, optimize the operating modes and the crusher design and develop automated verification and calibration methodology. It is offered to use automated selection of mathematical model parameters using large- or laboratory-scale experiments instead of deriving parameters from conventional intensive material tests (e.g. drop-weight test). Experimental data were obtained from a large-scale crusher designed and manufactured by the company “Mekhanobr-Tekhnika”. Both jaws have their drive shafts located asymmetrically; one jaw is driven in the upper part, the second at the base. The crushing process involves fragmentation of single smoothed rectangular granite particles of the same weight. During the experiment, the required parameters such as particle size distribution were obtained for further computer simulations. Based on the obtained experimental data, the Rocky DEM model was built. Simulation breakage parameters were calibrated using automated parameter selection methodology based on multiple set of parameter-controlled simulations. A good correlation of the experimental data and numerical simulation data was obtained. The methodology in combination with well-known capabilities of simulation modeling will help reduce the research time in the development of new mineral processing equipment.INTRODUCTION Preparation of rock mass for enrichment includes the power-consuming processes of crushing and grinding. Initial rock mass crushing is performed by means of drilling and blasting operations. To reduce the average size of a rock piece, primary crushers, mostly jaw crushers, are further applied. The advantages of the jaw crusher are simple design, easy maintenance and repair. One of the drawbacks is large oscillating masses and, thus, high power consumption during operation (55 - 200 kW). Jaw crushing simulation will help optimize the crushing process and improve further rock transportation and processing performance."

Jan 1, 2018

By N. Johnson, J. Quinteros

With the general trend across all commodities towards the treatment of lower grade ores, it is becoming increasingly important to develop efficient protocols for comprehensive mineralogical characterisation to allow the development of the most appropriate strategies for processing an ore. In the case of silver, there are more than 200 known silver bearing minerals which can make it challenging to identify them. Knowledge of the deportment of silver within an ore is one of the factors used to determine an appropriate processing strategy. Automated SEM-based tools are commonly used for mineralogical characterisation but the low-grade together with the large number of minerals that are potential hosts for silver means that often, complementary analytical tools must be used in order to properly account for the silver. The work presented in this paper is a demonstration of the approach that should be taken when identifying the deportment of silver in complex ores. Three complex, low-grade silver ores were characterised using the approach. The insights from the mineralogical characterisation were then used to inform the metallurgical testing that was undertaken. The results from the batch flotation testing clearly demonstrate the importance of understanding the mineralogy in order to select the most appropriate metallurgical processes.

Jan 1, 2014

It is well known that the crushing and grinding steps in the mineral processing of ores represent a substantial proportion of total energy, cost and carbon emission in mining. For instance a recent study calculated that 36% of the energy consumed by gold and copper producing mines in Australia was attributable to comminution (Ballantyne et al, 2012). Understanding this component of a business is essential in a world seeking to lower production costs, improve earnings and reduce its carbon footprint. The issue commands the attention and support of industry leaders in the mining sector, government, equipment manufacture, engineering design and research organizations. Furthermore, several researchers have often stated that globally, comminution processes consume between 3-4% of the world?s electrical energy production (Daniel and Lewis-Gray, 2011). In 2009-10, Australia?s Federal Government Energy Efficiency Opportunity (EEO) participants in the mining sector used 336.5 PJ, representing approximately 6 percent of Australia's total energy use. It is evident that the current practices of breaking rocks in tumbling mills are relatively inefficient (Fuerstenau and Abouzeid, 2002). Research and improved engineering design has established that a range of improved blasting, crushing and grinding techniques and flow sheets may lower project costs and carbon footprint. These include relatively simple process flow sheet strategies such as gangue rejection or pre-concentration prior to size reduction, a better combination of grinding technologies (both current and new systems), and selection of coarser grind sizes where ore and waste mineralogy allow. Yet, despite this systematic and detailed research, the industry remains somewhat reluctant to implement these strategies. CEEC (Coalition for Eco-Efficient Comminution) was established in 2011 to support knowledge sharing and change in an area of high-energy consumption for the global mineral industry. CEEC is a not-for-profit industry company, funded by grants from world wide industry companies, whose mission is to accelerate knowledge and technology transfer in the field of energy-efficient comminution. The key benefit to the mining sector arising from CEEC?s activities will be an increase in the rate at which more energy-efficient comminution data sets, processes, and technologies are developed, demonstrated, shared and applied. This will contribute directly to the industry?s target of reducing operating costs and carbon emissions. CEEC International Ltd and JKTech Pty Ltd teamed together to facilitate the inaugural CEEC Workshop, in June 2012. The purpose of the workshop was to produce a roadmap to provide guidelines for how (1) operations can achieve best EEC practice in the short to medium term, in collaboration with vendors, engineering companies and other service providers, and (2) what R&D is needed to achieve paradigm change in EEC in the medium to long term, e.g. 75% reduction in comminution energy in 10 years.

Sep 1, 2012

By H. Wotruba, L. Gronen, A. Hellmann, S. Sindern, J. Katzmarzyk

"This paper focuses on the beneficiation of the REE-Y-Nb-Zr complex ore from the ‘Khalzan Buregtei’ deposit, Mongolia. Pre-concentration based on mineralogical studies was investigated at the Unit of Mineral Processing (AMR) and the Institute of Applied Mineralogy and Economic Geology of RWTH Aachen University. In order to minimize the energy consumption in the most energy intensive grinding process a pre-concentration process using dry magnetic separation of particle sizes coarser than required for the liberation of the valuable ore minerals was designed. Dry magnetic separation in the particle size range of 63-250 µm is suitable as the pre-concentration method, due to the intergrowth of REE-Y-Nb-Zr bearing minerals with magnetic minerals determined by QEMSCAN© analysis. The results showed that a mass reduction of 45.3 wt.-% at high recoveries of REE, Y, Nb and Zr (90 wt.-% and higher) in the pre-concentration product was achieved at the beginning of the process chain. The improvement of process efficiency as shown in this study depends on the abundance and association of minerals affecting the magnetic properties (e.g. hematite) of the ores. Therefore, these mineralogical parameters are as important as grain size and ore grade for the geometallurgical evaluation of potential mining operations at ‘Khalzan Buregtei’.INTRODUCTION Polymetallic deposits containing other critical elements besides REE have the advantage of being robust to economic development and fluctuations of individual metal prices. (Gronen et al., 2016). These deposits can host economic grades of heavy and light REE, Y, Nb, Ta, Zr in complex mineralogical compositions. About 120 deposits of this type are known worldwide, including ‘Norra Kärr’ in Sweden, ‘Strange Lake’ in Canada and ‘Khalzan Buregtei’ in Mongolia which are not valued economically yet. (Salvi. & Williams-Jones, 2004.)"

Jan 1, 2018

By Avishan Atrafi, Marek Pawlik

"Gas dispersion properties of sodium salts of 6, 12 and 18-carbon fatty acids (hexanoic, lauric and oleic acid) were investigated as a function of pH. A strong effect of pH was observed on gas dispersion properties of fatty acids. At high pH for 12 and 18 carbon fatty acids, at which these surfactants formed a true solution, the gas dispersion properties were similar to those of MIBC. In the case of sodium hexanoate, which has a much higher solubility than the longer chain fatty acids and therefore does not form precipitates, the gas dispersion properties of this surfactant were strongly enhanced in the acidic pH range, where hexanoic acid was fully associated. This result is an indication that undissociated hexanoic acid is much more surface-active than anionic hexanoate. Only a small effect of the surfactant chain length on gas dispersion properties of the tested reagents was observed. The measured critical coalescence concentration (CCC95) values increase slightly by decreasing chain length and range from 5.8 x 10-5 mol/L (17.7 mg/L) for sodium oleate to 7.2 x 10-5 mol/L (16 mg/L) for sodium laurate at pH 10 and 1.9 x 10-4 mol/L (26 mg/L) for sodium hexanoate at pH 3.7. These are compared to CCC95 of MIBC, which is measured to be 8 x 10-5 mol/L (8 mg/L). The soluble molecular species were recognized as the most effective species in preventing bubble coalescence."

Jan 1, 2014

By B. P. Baruah

A good deposit of high sulphur coals of tertiary origin is existent in North eastern region of India. These coals are known to have indifferent characteristics in comparison to other Indian coals. The general Physico-chemical characteristics are low ash and high volatile matter, calorific value and sulphur content. Sulphur in these coals (70-95% of organic) is mostly affixed to the structure of the coal. Owing to the stringent environmental regulations, the utilization of these coals has severe limitations due to high sulphur content. In the present investigation, sulphur incorporation in to these coals has been discussed along with possible organic sulphur functionalities. The various desulphurization techniques carried out for removing sulphur from these coals have been discussed. Two step oxidative desulphurization processes has been found to be most efficient for organic sulphur removal along with mineral matter and potential toxic elements. Keywords: oxidative desulfurization, potential toxic elements, sulfur incorporation

Sep 1, 2012

By Petrus van Staden, Dragan Milanovic, Francisco Sánchez, Eero Kolehmainen, Carlos Frias

"Currently there is no economical and viable process for on-site metal extraction from Low Grade, Complex or Poly-metallic deposits, and even more, there is not any industrial process or technology able to deal with polymetallic or bulk concentrates containing Cu+Zn+Pb base metals and also precious metals. Traditionally, metals recovery from polymetallic sulfide deposits is performed by mining, selective flotation to separate Cu, Pb and Zn concentrates, and finally, smelting/refining of those concentrates to obtain the refined metals. In many cases, selective flotation of that kind of complex ores produces low metals recovery and low concentrate quality containing impurities such as Hg, As, Bi, etc., which results in high penalties in treatment and refining charges, and consequently, worsening the economy of the mining business. Recovery of the valuable metals from Polymetallic, Complex or Low Grade ores could then be maximised by producing bulk concentrates or middling flotation products to feed novel hydrometallurgical processes, like the integral metallurgical system that is currently under development within the INTMET project. For example, producing bulk concentrates would increase more than 100% Cu+ Zn+Pb cumulative recovery versus conventional selective flotation. Founded by the Horizon-2020 EU Programme, the INTMET Project was started in February 2016 and will be running over three years. The INTMET consortium is led by Cobre Las Cruces (Spain) and integrates twelve partners from seven EU countries, and including Serbia and South Africa as well. The INTMET project represents a challenging opportunity to develop suitable technological solutions to deal efficiently with difficult, polymetallic and complex sulphide ores that are abundant in Europe and worldwide. Main activities carried out during the first 18 months of the INTMET project development includes: (i) An atmospheric leaching pilot plant having a capacity of 300 kg/h bulk concentrate which has been installed and operated continuously for nine months at the Las Cruces mine; (ii) Pressure leaching test work developed by Outotec; (iii) Bioleaching test work performed by Mintek in collaboration with MMI Bor. Prior test work was applied on bulk concentrate samples supplied from Spain, Portugal and Serbia. Some of the results of these technological developments have been very positive and are presented in this paper."

Jan 1, 2018

By Peter J. Coghill, Michael J. Millen, Brian D. Sowerby, Kirby D. Cunningham

"CSIRO Minerals has developed an integrated particle size analysis system for deployment in the grinding circuits of minerals processing plants. The system includes a slurry sampling station, a de-aeration tank and an ultrasonic particle size analyser (UltraPS). The UltraPS analyser is based on ultrasonic attenuation and velocity spectrometry combined with gamma-ray transmission. The technology is applicable to the measurement of 0.1 to 1000 µm diameter particles directly in highly concentrated slurries without dilution. The analyser incorporates a gamma-ray transmission gauge utilising an ultra-low activity radioisotope source that is exempt from International Atomic Energy Agency (IAEA) and Australian licensing regulations.The UltraPS analyser consists of a submersible probe and an electronics package. The probe can be immersed directly in a minerals processing plant stream if the aeration level in the stream is low. For applications where a de-aerated slurry stream is not available, CSIRO has developed an integrated system that includes a sampling station, a de-aeration tank as well as the UltraPS analyser itself. A schematic drawing of the continuous flow gravity fed system is shown in the figure. A commercial sampling system is used to supply slurry at a rate of 2.5m3/hr to the deaeration tank. The aim of the de-aeration tank is to remove air in the slurry to a level where meaningful particle size measurements can be performed. The tank volume is about 0.2m3, thus giving the slurry flowing through the tank a mean residence time in the tank of approximately five minutes. Tests at a number of concentrators have shown that five minutes is sufficient time for slurry to de-aerate to a level where ultrasonic measurements can be made. The tank incorporates an ultrasonic level detection sensor and flow to the deaeration tank is adjusted based on the level of slurry within the tank. The UltraPS probe is mounted through a flanged section of duct, which is bolted to the bottom of the de-aeration tank."

Jan 1, 2003

By Renato S. Costa, Afonso H. Martins, Flávia D. Mendes

"This paper presents some important aspects regarding the ion exchange treatment of an Ni and Co sulphate acidic liquor using chelating resins. Chelating resins possessing iminodiacetic or bis-picolylamine functional groups were compared in terms of nickel and cobalt recovery. The experimental resin with bispicolylamine functionalities (Dowex M4195) was evaluated with respect to Ni and Co uptake, and compared with Rohm &Haas commercial chelating iminodiacetate acid resin. The Rohm & Haas chelating resin, Amberlite IRC 748, with its weakly acidic groups, did not work in acidic solution but exhibited good results at pH 4 and above. The resin that efficiently removed metals from high acidic solutions was the bis-picolylamine resin. Maximum nickel uptake values ranged between 85 g and 112 g Ni per Kg of resin.The experimental part dealt with the working conditions, resin characteristics and the influence upon the resin maximum exchange capacity of the following factors: nickel concentration, temperature, pH and resin-to- solution ratio. Based on the experimental data obtained, it has been proposed a innovative technological treatment."

Jan 1, 2003