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By V. G. Minenko, V. A. Chanturiya, A. L. Samusev

Eudialyte is one of perspective resources of zirconium and other rare earth elements (REEs). Large reserves of eudialyte concentrated in the Murmansk region of the Russian Federation. Usually, technologies of REE treatment include the decomposition of eudialyte concentrate in different acidic, extraction and utilization of all components. The main problems in the leaching of eudialyte include are: the formation of an unfiltered silicon-containing gel; low recovery of REE; difficulty extraction of metals from the productive solution; high aggressiveness of the reagents. One of the promising trends of intensification of the processing of hard-to-degrease rare metal raw materials is the use of energy methods for affecting mineral suspensions. These methods make it possible to increase the efficiency of break up fine-dispersed mineral complexes and extracting micro- and nanoparticles of a valuable component in subsequent deep processing. The purpose of this work is to investigate the effect of energy impacts on the nitric acid leaching of eudialyte concentrate. Experimental studies were carried out in a developed laboratory facility that makes it possible to evaluate the effect of electrochemical, ultrasonic and combined effects on the leaching of zirconium and REE from eudialyte concentrate. The studies carried out on the samples of eudialyte concentrate with the size class of -0.315 + 0.063 mm showed that the use of electrochemical and acoustic effects increases the extraction of ZrO2 in the production solution in 1.6 - 2.5 times, REE in 1.3 - 2.2 times, respectively. An analysis of the microstructure and phase composition of the surface of the eudialyte concentrate showed that the intensification of the leaching process is due to surface cleaning from the silicon-containing gel, as well as the opening of capillary channels and microcracks, which accelerates mass-transfer processes. The results obtained open wide opportunities for creation of modern and effective technology of processing of eudialyte concentrate, producing high-quality zirconium products and REE.

Jan 1, 2018

By Seoul National University, Ki-Ho Kim, Jong-Pyo Kim, Sung-Min Joo, Hee-Chan Cho, Hyung-Seok Kim

Aragonite was synthesized in addition of Mg2+ ion and SrCO3 seed by carbonation process, and the best condition and mechanism of the synthesis was studied by analysis of continuous pH change, ICP, XRD, and SEM. As MgCl2•6H2O addition increased, aragonite phase increased at condition of CO2 flow rate of 100 mL/min and stirring rate of 250 rpm. It was the dissolution of Mg(OH)2 that determined overall reaction time. As SrCO3 seed addition increased at 0.2 mole MgCl2•6H2O, the amount of aragonite increased and the aspect ratio was from 5 to 9. And it was thought that Mg2+ ion prohibited calcitetransformation of aragonite formed by SrCO3.

Jan 1, 2003

Beneficiation and dephosphorization of refractory oolitic hematite ore are investigated in this paper. It is shown that single magnetic separation, gravity separation or flotation is unable to recover iron effectively from the ore due to the complex mineralogy. The joint separation by spiral chute-shaking table shows a prospect for the treatment of the ore. An iron concentrate with 58.67% iron grade and 51.93% recovery is obtained by the joint separation of spiral chute and shaking table under the fineness of ?0.074mm 90% and dispersant dosage of 2kg/t for a sample ore of 37.51% Fe and 0.88% P. However, P content in the concentrate is still up to 0.52%. Dephosphorization from the concentrate is hence carried out. The final iron concentrate assaying 59.26% Fe and 0.056% P is obtained when the concentrate obtained by joint separation is leached by sulfuric acid of 1% (mass fraction) with solid percentage 10% at room temperature for 10min.

Jan 1, 2014

By T. Kumaresan

The Bayer process used for refining bauxite to smelting grade Alumina serves as the linchpin of the Aluminum production industry worldwide. Even though the process is well established, the presence of impurities in the liquor affects the quality of product and imposes a major economic cost on the industry. This review article focuses on the issues pertaining to Gibbsitic (Al2O3.3H2O) precipitation circuit. The comprehensive review provides a basic understanding of the aluminum trihydrate precipitation and agglomeration phenomena. Crystal growth rate and agglomeration play a significant role in determining the output PSD of agglomerates. Hence, the effect of certain thermodynamic and hydrodynamic parameters along with the impact of impurities (oxalates, aldols, acids etc.) and additives on hydrate growth has been reviewed.

Sep 1, 2012

By O. V. Suvorova, V. G. Minenko, D. V. Makarov, A. L. Samusev, E. A. Selivanova

"Saponite is a valuable marketable product widely used foundry, metallurgy and construction, in the chemical, food and consumer goods industries, in medicine, and in agriculture.The feasibility of producing of high-quality construction materials with enhanced physical-chemical and decorative characteristics from saponite-containing products has been given a scientific basis and experimentally validated. The compressive strength of the samples in the sintering temperature range of 800-1000 ?? varied between 35 and 80.9 MPa; the bending strength 8 and 26.7 MPa, which is superior to the high-grade ceramic bricks of the M-300 brand. It has been established that the saponite-containing product obtained using the electrochemical separation of process water has a high sorption capacitance relatively the heavy-metal ions such as nickel and copper (40.7 and 99.8 mg/g, respectively). As a result of sintering at 750 ?? the sorption capacity of the sorbent for the nickel and copper ions increased to 194.2 and 212.8. Using the XRD and SEM with energy-dispersive spectroscopy studies, we diagnosed the metal-containing phases and validated the metal sorption mechanism.This study opens up the possibility of practical realization of the saponite-containing product as high-quality building materials and heavy-metal sorbents while addressing the issue of process water treatment. INTRODUCTION The Lomonosov deposit of the Archangelsk diamondiferous province accommodates 10 kimberlite pipes. The anticipated volume of diamond-bearing ore and dump rock to be removed before reaching the open-pit mining limit is 300 mln t (Karpenko, 2009; Bezborodov, etal. 2003). Rock in the deposit is almost completely displaced by clay minerals, predominantly saponite, amounting to 90% in the vent facies (Karpenko, 2009)."

Jan 1, 2018

By M. Saghaeian, R. Hejazi, M. Farahani, M. Dehghani, A. Tohry

"Wet tailing dams of iron ore processing plants typically contain a significant amount of valuable minerals. In more recent years, due to the increase in iron’s prices and technological innovations, as well as the low energy consumption which required for processing of materials from tailings, dams can consider as potential valuable deposits. However, the production of iron concentrate from tailings is usually complicated where the high moisture content of the material, the high clay content and the presence of chemicals of processing such as flocculants, acids and flotation reagents, all make materials highly sticky which can be easily swollen. In the present paper, the optimization of operational parameters to recover ultrafine hematite iron ore from the wet tailings dams of the Chador-malu iron ore mine was investigated. The optimization of operational parameters, showed that with modification of the washing unit components for slurry making, the challenge of constraints from feeding the plant could be overcome. To decrease the magnetite content in the tail stream of the medium intensity magnetic separation (MIMS) and subsequently increase the efficiency, the orifice of the cleaner tail flow exit pipe was changed from 7 inches to 3 inch and yoke angle changed from 14 to 8 degrees. These changes increased mass yield by 3% and decreased the magnetite content in the final tailings to 1.2%. By recirculating the cleaner SLons of final tailings within the circuit, the solid percentage of the feed to rougher SLons decreased to around 15%, and as a result the matrices were not overloaded that easily, and mass yield increased to about 13% from 7%. All the above mentioned optimizations were achieved without significantly affecting the concentrate Fe grade."

Jan 1, 2018

By A. P. Chaves, D. Jose Neto, M. G. Bergerman, E. S. Mano

"More complex ore comminution and concentration operations have found increasing application in the mining industry due to lower grades and higher complexity of the available ores. An alternative to coping with the higher capital and operating costs of ore processing plants is the use of pre-concentration stages. They allow removing a significant mass of material with little or no content of the relevant mineral before the ore is fed into the processing plant, with the consequent reduction in the mass to be processed in downstream operations. Significant benefits arise out of the use of pre-concentration, such as higher contained metal output without the need to increase the grinding or flotation capacity, and longer mine life. The grade of marginal ores could be enhanced to a level that would make their exploration economically feasible, which would result in increasing exploitable reserves. Nevertheless, few studies to date have assessed the resulting impacts on ore grinding energy consumption and wear after the gangue is removed through pre-concentration operations. This study evaluated the energy consumption and wear of grinding circuits in Brazilian mining operations in which the feed has gone through a pre-concentration stage. Such assessment was based on different samples of sulfide and oxide ores. Laboratory tests were carried out to investigate the power consumption and wear of grinding circuits with and without a pre-concentration stage. Laboratory test results were used to simulate industrial grinding circuits based on both alternatives and illustrate the environmental and economic benefits of each one.INTRODUCTION Increasingly complex ore concentration operations in several stages have found broadening application in recent years in view of lower grades and higher complexity of the available ores. An alternative to coping with the higher capital and operating costs of ore processing plants is the use of pre-concentration stages. Different ore processing technologies can be used for that purpose, such as magnetic separation, density segregation, and separation methods based on high-tech sensors (ore sorting). Currently, the most common methods are gravimetric processes, in view of their low cost, particularly jigging and dense medium separation methods, such as the drum and cone separators manufactured by Western Machinery Company, Teska, Drewboy, Norwalt, Dynawhirlpool and Tri-flo, and dense medium cyclones (CAMPOS; LUZ; BRAGA, 2010). The use of dry ore sorters has also grown significantly in recent years (Jose Neto et al. 2017). The selection of the separator type depends essentially on the ore particle size, required flows, and operating density ranges. All these methods may even be used after preferential blasting in mining (Grigg & Delemontex, 2015)."

Jan 1, 2018

By Bisweswar Das, Barada Mishra, Hrushikesh Sahoo, Swagat Rath

Banded hematite jasper (BHJ) containing 45.2% Fe, 32.64% SiO2, 0.63 % Al2O3 and 1.25 % LOI is found difficult to beneficiate either by magnetic or flotation techniques due to fine intergrowth of jasper with hematite. Phase transformation by reduction roasting with activated charcoal followed by low intensity magnetic separation to achieve a suitable iron concentrate has been attempted in this study. The mineralogy of the ore and different roasted products has been studied by X-ray powder diffraction (XRD) and scanning electron microscope (SEM) to understand the reduction mechanism. The magnetite formation is observed at 850ºC while metallic iron appeared at a higher temperature. The effects of reduction variables such as reduction time (30-270 min), temperature (750-1050ºC), and reductant (1-12 %) using activated charcoal are studied. An iron concentrate with 64.65% Fe and 55.8% recovery could be obtained under optimum conditions of temperature: 850ºC, time: 1.5 h, and reductant: 6% by weight.

Jan 1, 2014

By C. A. C. Sequeira, G. N. Anastassakis

Electrochemical processes occur on nano-, micro- and macro- scale in numerous applications such as fuel cells, batteries, hydrogen production, mineral extraction, water treatment, electrotherapy, sensors and many others. In most of these applications, gases evolve either at one or both electrodes due to electrolysis. These gases form bubbles play a crucial role in electrochemical systems. For example, in electrowinning (EW) that is used to extract and refine metals such as Cu, Zn, Ni, Mn, and Cd from their solutions, in most cases the solution is acidic and oxidation of water molecules at the anode is the common counter reaction, which results in the liberation of oxygen bubbles. This generally requires a high overpotential and accounts for a considerable percentage of the energy consumed in metal EW electrolytic cells, apart from producing acid mist that is very corrosive for other cell equipment and building structures. The behaviour of bubbles in electrochemical systems is still a complex challenging topic which requires a better understanding of gas bubbles hydrodynamics and their interactions with electrode surface and bulk liquid, as well as between the bubbles themselves. The objective of the current paper is to briefly review the fundamental hydrodynamics of both gas bubbles on the electrode surface and gas bubbles interaction with the liquid bulk solution. The current work also investigates the impact of gas bubbling and some operating parameters in copper EW, such as current density (100-500 A/m2), temperature (25-75ºC), acidity (50-300 g/L) and a typical chemical mist suppressant (<50 ppm). The results clearly show that both suppressant and temperature reduced the overall surface tension of the solution. Also, chloride concentration and applied current improved electrolyte flow and copper quality at higher current densities. The current paper contributes to the development of mineral processing (specifically to copper hydrometallurgy), as it deals with fundamental hydrodynamics and interactions of gas bubbles that formed during copper EW and play a crucial role in copper electrochemical systems.

Jan 1, 2018

By P. Somasundaran, Tarun Bhambhani, S. Murthy Khandrika, Partha Patra, D. Nagaraj

Fine and ultrafine mineral particles, particularly if, altered mineralogically, can have detrimental effects on selective separation of minerals. Behaviour of altered mineral fines has been investigated in this work by studying the effects of weathered silicate slimes on the selective separation of copper minerals, particularly with focues on effect of the pulp rheological behaviour, which plays a governing role in the process. Physicochemical properties of these altered silicates fines such as morphology and surface charge are proposed to be responsible for the adverse rheological effects and resultant selective separation. Here, the effect of a number of problematic aspects such as water chemistry, froth stability, physicochemical aspects of gangue mineral aggregates on flotation sub-processes has been studied. Processing problems owing to the physical aspects of the gangue minerals, shape and morphology, are primarily due to uncharacteristic increase in the pulp viscosity. While problematic aspects other than impact of pulp rheological behaviour can interfere with each other in their contributions to how they affect the sub-processes, effects owing to pulp rheological behaviour have a direct impact on the flotation performance. Subtle increase in pulp viscosity can interfere with sub-processes in flotation leading to decrease in recovery and grade, and it is difficult to assess the effects due to such subtle changes. Reagent based strategies to overcome the problematic aspects has been explored here.

Jan 1, 2014

By Yessengaziyev Azamat, Almagul Ultarakova, Onayev Murat, Barkytova Botakoz

"The research is aimed at solving the processing of waste products of titanium-magnesium production. The aim of the research is to extract synthetic carnallite and industrial products enriched with niobium from waste products of titanium-magnesium production. Analysis of the current state of the titanium and magnesium production in the Republic of Kazakhstan shows the availability of significant amounts of chloride wastes containing valuable components. Magnesium and potassium with an average content of 50-60 % potassium chlorides, 25-30 % magnesium chlorides are lost in the wastes of the titanium and magnesium production. Ust-Kamenogorsk Titanium Magnesium Plant JSC (UKTMP) currently imports carnallite that is a KCl-MgCl2X6H2O binary salt at quite high prices. Chloride wastes of titanium production, sublimates of dust chambers of a titanium chlorinator, sludge of a magnesium electrolytic unit and sludge of a carnallite chlorinator has been chosen as the targets of our research. The analysis of niobium distribution within any solid waste of a titanium slag chlorination process in UKTMP JSC showed that the highest content of niobium is in the sublimates of dust chambers of a titanium chlorinator in the ranges from 0.26 to 1.0 %. Among the niobium extraction technologies considered, the known method of its extraction from the chloride waste is leaching with weak solutions of mineral acids or alkalis in order to convert the chloride salts into the solution to be used for synthetic carnallite extraction. Besides niobium, other impurity components are transferred to the cake and shall be separated from the base metals. The effective method for this is the chlorination process enabling niobium transfer into the sublimates in the form of chlorides and thus separating it from the majority of the impurities. The condensed niobium chlorides are hydrolyzed transferring it into sediments in the form of oxide. New ways of processing waste products of titanium-magnesium production with the receipt of marketable products are relevant in the development of processing of mineral raw materials."

Jan 1, 2018

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 C. Abbruzzese, F. Vegliò, S. Ubaldini, R. Massidda

"Gold solubilised during cyanidation can be recovered by precipitation (Merrill-Crow process) or by adsorption onto activated carbon, these being the techniques applied in industrial plants.Precious metals (Au, Ag) adsorbed onto activated carbon are extracted during a subsequent stage in aqueous phase, by various technologies, such as hot elution (70-80°C) or under pression desorption (100-130°), with hydro-alcoholic solutions.This stage is of great interest from an economic point of view, due to the high energy costs. Temperature represents the critical kinetic factor.The aim of this paper was to study the influence of different water/organic solvent mixtures (isopropyl alcohol, ethanol and ethylene glycol) on the desorption process.The experimental work was carried out on laboratory scale, using activated coconut carbon with different temperatures and extraction times, without adding cyanide.Best results have been obtained in this order: isopropyl alcohol > ethylene glycol > ethanol. Starting from gold concentration of about 5 g Au per kg of carbon, best kinetics resulted in 97-100% of gold extraction, after 8 hours of desorption, at a temperature of 80ºC."

Jan 1, 2003

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 R. K. K. Mbaya

The concept of adsorption or separation of platinum anions from base metal cations in chloride media using native or chemically modified activated carbons has been discussed in various journals within the context of batchwise systems. In our research work, a fixed-bed column, loaded with native and amine-immobilized activated carbon pellets (Norit RO 0.8), was used to study selective adsorption of platinum ions from chloride media at different flow rates, bed depth and initial metal concentrations. The kinetics, mass transfer characteristics, breakthrough data and separation factors (ß(Pt/Fe) and ß(Pt/Cr)) were quantitatively analysed and modeled. The bed-depth service time (BDST) model was used to model the breakthrough curves successfully in fixed-bed columns and also the dispersive diffusion in the radial and axial directions of the bed were evaluated. The inner diameter of the column was 3 cm and the bed depth was between 1.0 cm and 2.5 cm. Concentrated 4 M HCl acid solution was used to elute the fixed-bed column. It was demonstrated that amine-treated activated carbons provides superior separation factors between platinum and base metals (Fe, Cr). Results showed also, that 95% saturation was reached within 10~26 hours depending on the nature of ACs at a flow rate of 11 mL/min and initial concentration of 5 ppm.

Jan 1, 2014

By K. C. Corin, M. S. Manono, R. M. Manenzhe, J. G. Wiese

"Environmental concerns necessitate the recycling of process water within mining operations. Given that recycled water is chemically different from fresh water, and collectors are added such that they adsorb at the liquid-particle interface, changes in the aqueous phase are expected to affect collector adsorption. A Finnish nickel-copper ore was floated in synthetic plant waters of varying ionic strengths and plant waters obtained at Boliden Kevitsa Mine, with aerophine and sodium isopropyl xanthate as collectors. Of the tested waters, the copper thickener overflow was the least conducive to xanthate adsorption and valuable mineral recovery. The nickel thickener overflow, standard process water, and raw water were the most conducive to xanthate adsorption. For the raw water and nickel thickener overflow, increased adsorption correlated with increased valuable mineral recovery. Further, recycling xanthate retained in water affected the selectivity of the collector and hence the concentrate grades.INTRODUCTIONFlotation is a separation process that exploits the differences in the surface properties of the particles being separated. The efficiency of separation is dependent on the degree of hydrophobicity achieved by the particles meant to be floated, which are, in most cases, valuable minerals. The hydrophobicity is in turn dependent on the adsorption of the chosen collector onto the surfaces of the floated particles (Fuerstenau, 1984; Taggart and Hassialis, 1946). Empirical findings suggest that species dissolved in solution strongly influence collector adsorption and overall flotation response (Fuerstenau and Chander, 1986). Due to environmental concerns, it is becoming more pertinent for mining plants to recycle process water and hence limit the usage of potable water. There is an interest to ensure minimal discharge of plant water into the environment, as this water is typically polluted with process reagents that may render it toxic (Levay et al., 2001).Recycled water, however, has been shown to adversely affect flotation. Reagent efficiency can be reduced due to increased suspended solids. A loss of mineral recovery can occur due to competitive adsorption between reagents and other dissolved species, loss of reagents due to precipitation, and unwanted reactions. Further, a reduction in grade can occur due to non-selective coating of reagents on valuable and gangue minerals, and hydrophobic coating of microbiological material on gangue, causing unwanted flotation. Yet despite these drawbacks, water reuse has the advantages of minimal fresh water use and reduced reagent consumption by recovering the unconsumed reagents retained in wastewaters (Bruckard et al., 2011; Levay et al., 2001; Shengo et al., 2016; Slatter et al., 2009)."

Jan 1, 2018

By S. M. Javad Koleini

Processing of phosphate ore sample was investigated for increasing phosphate content and reduction of its gangue minerals such as carbonates and silicates. Experimental designs were per-formed using Taguchi method. Different flotation methods were investigated for Moundon phosphate ore sample and three methods were used as follow: direct cellophane flotation, reverse calcite flotation and reverse quartz flotation. Because of the sensitivity of cellophane flotation to slime content, prior desliming was carried out before the experiments. Direct flotation experiments carried out and a concentrate contained 23.80% P2O5, 6.88% SiO2 and 72.33% recovery were produced. The achieved P2O5 content in the produced concentrate from reverse flotation of calcite was 26.44% and the recovery was 82.56%. The concentrate products obtained at optimum conditions by direct flotation of phosphate and indirect flotation of calcite were subjected to indirect flotation of calcite and direct flotation of appetite and final concentrates with P2O5 grade of the order of 24.19% and 26.96% were obtained, respectively. It was concluded that one stage direct flotation is unavoidable to achieve a product with low SiO2 content.

Jan 1, 2014

By Jens Markowski

The EU Directive 2000/53/EC on end-of life vehicles (ELVs) states that in 2015 at least 85 wt.-% of a vehicle has to be reused or recycled. This result in the obligatory need to separate additionally metallic and other components of the automotive shredder residues (ASR), so that they can be professionally prepared for recycling and reuse further. Currently the iron-containing fines of ASR are deposited as it is not possible to process in blast furnaces due to its particle size (< 4 mm), composition and material properties. Additionally problems are also caused in handling and transportation (dust) of the material. This work focuses mainly on the ASR materials utilization in blast furnaces. Material was further separated into two consecutive fractions by carrying out repeated crushing and magnetic separation twice. The two fractions have significantly higher iron content (up to 75 wt.-%) compared to the initial material mixture. The materials were assessed for their usage in blast furnaces based on the possible pelletisation with and without binders, stability of pellets, shape and size of pellets, etc. Pelletisation of the material was carried out with a single mould pellet press. Further lignite coal was added to the mixture as additive which improved the pelletisation behavior and the mechanical stability of pellets. Lignite coal was chosen as a reducing agent in the blast furnace process contributing towards additional savings in energy supplied. The experiments reveal that the production of pellets from iron-containing fines is possible with a lignite coal admixture of about 15 wt.-%. These pellets displayed good mechanical stability and can be used in blast furnace processes in recovery of the recyclable metals which are currently not recycled. The recycling of not yet recyclable metals would reduce the deposition and can be easily adopted into the economic cycle by their utilization. Keywords: Automotive shredder residue (ASR), FE-fines, pelletisation

Sep 1, 2012

By K. C. Corin, M. S. Manono, R. M. Manenzhe, J. G. Wiese

"Environmental concerns necessitate the recycling of process water within mining operations. Given that recycled water is chemically different from fresh water, and collectors are added such that they adsorb at the liquid-particle interface, changes in the aqueous phase are expected to affect collector adsorption. A Finnish nickel-copper ore was floated in synthetic plant waters of varying ionic strengths and plant waters obtained at Boliden Kevitsa Mine, with aerophine and sodium isopropyl xanthate as collectors. Of the tested waters, the copper thickener overflow was the least conducive to xanthate adsorption and valuable mineral recovery. The nickel thickener overflow, standard process water, and raw water were the most conducive to xanthate adsorption. For the raw water and nickel thickener overflow, increased adsorption correlated with increased valuable mineral recovery. Further, recycling xanthate retained in water affected the selectivity of the collector and hence the concentrate grades.INTRODUCTIONFlotation is a separation process that exploits the differences in the surface properties of the particles being separated. The efficiency of separation is dependent on the degree of hydrophobicity achieved by the particles meant to be floated, which are, in most cases, valuable minerals. The hydrophobicity is in turn dependent on the adsorption of the chosen collector onto the surfaces of the floated particles (Fuerstenau, 1984; Taggart and Hassialis, 1946). Empirical findings suggest that species dissolved in solution strongly influence collector adsorption and overall flotation response (Fuerstenau and Chander, 1986). Due to environmental concerns, it is becoming more pertinent for mining plants to recycle process water and hence limit the usage of potable water. There is an interest to ensure minimal discharge of plant water into the environment, as this water is typically polluted with process reagents that may render it toxic (Levay et al., 2001)."

Jan 1, 2018

By G. Y. He

The large-scale 8.53m×3.96m (28?×13? F/F) SAG mills was first applied in Donggua Hill Copper Mine which processes 13,000 tons ore per day. The crushing and grinding circuit went into operation in the Donggua Hill plant in October 2004. However, at the beginning, the productivity of grinding only reached 58% of the capacity expected and some indexes of the crushing and milling circuit didn?t meet the requirements. Especially, the total load of the 8.53m×3.96m (28?×13? F/F) SAG mills was up to 34%~41% (25%~30% designed)and some hard rocks with the size of 25~70mm, which can?t be treated as a medium or even would be crushed and make larger ores or steal balls necessary, were seriously accumulated in the SAG mills. Consequently, they occupied the effective mill volume which in turn reduced the efficiency of the SAG mills and increase the energy consumption. In order to solve the problem of accumulation in the SAG mill and increase its productivity, some measures were taken, such as passing more hard pebble through the grate at mill dis-charging end, changing the type of steal balls and so on. And the results showed that these measures functioned well and had good effects, which is that the filling percentage of the SAG mills has been reduced to 26%~29% from 34%~41% with the composition of particle sizes improved a lot and the productivity increased by 77.4% reaching up to 13,380 tons per day.

Jan 1, 2014