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By M. Ghiani, P. Massacci, A. Manni, R. Peretti, Center for Mining and Mineralurgical Studies, S. Serranti

"The research study has been devoted to point out the better way to process a colemanite concentrate characterised by a high content of two kind of As sulphides (realgar and orpiment) finely disseminated in the matrix of the boron mineral.Scanning Electron Microscopy analyses have been carried out to determine all the mineralogical constituents and to evaluate their distribution, frequency and mutual relationships.There is a not neglectable part of realgar highly disseminated into the colemanite crystals.The orpiment recurs in small acicular crystals of 20÷30 µm in length and 5 µm in width, very difficult to liberate from the colemanite mineral particles.The colemanite concentrate, in fact, has been addressed to a chemical plant which products were boric acid and gypsum, the contaminated by As. It was unacceptable for further applications and very dangerous if rejected in the environment.Grinding tests under dry and wet conditions have been carried out in order to evaluate the liberation modality of the As sulphide minerals from the colemanite.Some difficulties have been overtaken in order to obtain a selective liberation of the As sulphides from the colemanite even if a certain decreasing in As grade in the higher size classes has been registered.All the comminution products have been analysed by SEM monitoring the liberation degree of the mineralogical constituents.Flotation tests have been carried out after different comminution flow sheet adopting different modulating conditions in order to evaluate the influence of the following parameters:• collector concentration versus contaminants concentration (As minerals) in the froths;• kind and quantity of the frothing agent to maximise the mineral recovery in the froths;• kind and quantity of the modulating agents to maximise the selectivity of the process;• conditioning modalities in order to obtain a suitable dispersion of fines and to avoid segregation of Asbearingparticles together with colemanite ones;• solid/liquid ratio of the pulp to minimise the water flow into the plant."

Jan 1, 2003

By U. Dmitrakova, G. Sedelnikova, D. Kim, E. Savari

"The paper presents the results of research on the development of gold and silver extraction technology from refractory gold sulphide flotation concentrate of one deposits of Nord-East of Russia. The concentrate is due to the complex mineral composition. Gold and silver are finely disseminated in sulphide minerals (arsenopyrite and pyrite partially oxidized by 7-11%). These are characterized by high content of silver 219 g/t and sulphide sulfur 32%, the presence of poorly soluble silver minerals (silver sulfosalts, fahlore, finely dispersed hypergenic acanthite in iron hydroxides and jarosite, etc.), and impurity minerals capable of interacting with cyanide (pyrrhotite, marcasite, nonferrous sulphides) and causing higher than normal cyanide consumption. Pretreatment of refractory sulphide concentrate by biooxidation using a mixed association of mesophilic and moderately thermophilic bacteria at a temperature of 36-40 °C for 120 hours oxidized arsenopyrite by 97.5%, pyrite by 93.5%, unlocked refractory gold, and generally oxidized the minerals absorbing cyanide and oxygen before cyanidation. Further oxidation of these minerals-absorbents was facilitated by the aeration in calcareous medium of the solid biooxidation residues of the concentrate. Sorption cyanidation of the solid biooxidation residues with addition of lead (II) of recovered 91.2% of gold and 82.9% silver from biooxidation residue, compared with 80.1% and 46.6%, respectively, for sorption cyanidation without the preceding biooxidation step. Biooxidation of the concentrate prior to cyanidation improves the recovery of precious metals, especially silver, and significantly reduces cyanide consumption from 18.7 kg/t to 3-5 kg/t of concentrate. INTRODUCTION Biooxidation of gold sulphide concentrates using acidophilic microorganisms has been successfully applied worldwide (van Aswegen et al., 2007; Gericke et al., 2009; Sovmen et al., 2007; Sovmen et al., 2009). At least 15 full-scale plants for tank biooxidation of sulphide concentrates are presently in operation, and the construction of new ones is planned (Bulaev et al, 2015)."

Jan 1, 2018

By Xiao Ni

Alkyl hydroxamic acid was shown to be a suitable collector for the flotation of pyrochlore from carbonatite niobium oxide ores. In the direct batch rougher flotation from the ore without desliming, over 85% of the pyrochlore can be recovered at about 30% mass pull. Cleaner flotation tests showed that the rougher concentrate can be upgraded. The adsorption mechanisms of octyl hydroxamic acid (OHA) were studied by using high purity pyrochlore and calcite mineral samples and employing analytical measurements such as Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and UV/VIS spectroscopy. FTIR showed a shift of the vibrational frequencies of the carbonyl group in hydroxamic acid after adsorption on pyrochlore and calcite, and the shift was more pronounced on pyrochlore. XPS results indicated a lowering of the binding energies (chemical shift) of Nb3d5/2 and Ca2p3/2 electrons on pyrochlore, and the lowering of the binding energies of Ca2p3/2 electrons on calcite, again with the shift being more pronounced on pyrochlore. The results indicated hydroxamic acid formed stronger complexes with pyrochlore than with calcite. Adsorption isotherms indicated that OHA adsorbed more on pyrochlore than on calcite at low concentration. At high concentrations, the adsorption densities on both minerals were similar. All results explained the observed selectivity of the reagents in the flotation of the carbonatite niobium oxide ores.

Sep 1, 2012

By Mark Viduetsky, Dmitry Tropnikov, Victor Maltsev, Victor Sokolov, Alexander Purgin, Andrey Panshin, Alexander Bondarev, Pavel Kozlov, Igor Garifulin

"CFM pneumatic flotation machines were developed by the Institute of Materials Science and Metallurgy, UrFU, and designed to concentrate a wide range of ores and man-made materials. A key principle of work is pulp preparation for flotation owing to its saturation with finely dispersed air bubbles in ejectors. CFM plants, their advantages over domestic and foreign prototypes are described. CFM pneumatic machine commercialization resulted in: - machines demonstrated high floatation efficiency for concentration of rebellious pyrrhotite-bearing copper and zink by simultaneous floatation of copper and zinc minerals and depressing pyrrhotite. CFM- 1400M introduction allowed simplifying and optimizing the flow chart and increase extraction of copper - by 5.4%, zinc - by 9.5% and improve the quality of copper (3% Cu) and zinc (1.5% Zn) concentrates. - due to copper pyrite concentration by using CFM 1400M overall copper recovery was increased by 1.5 %, and the content of copper in concentrates - by1%. According to the results of pilot runs, the use of CFM flotation for zinc cakes concentration strongly intensifies the process of cleaning water-soluble metal compounds and, thereby, increases the efficiency of flotation concentration and subsequent milling. CFM machines showed higher specific capacity (three or four times higher) (both for feed material and froth product). Specifically, CFM froth product has higher content of useful elements (silver by 0.014 % abs. zinc by 0.31% abs.) and better extraction (silver by 6.08% abs., zinc by 0.31% abs., and sulfide sulfur by 13.7 %). Sulfide sulfur content of CFM product chamber as compared to mechanical flotation machines is two times lower (0.48 vs. 0.95 %)."

Jan 1, 2014

By S. Gomez, P. A. Bebswa, A. N. Mwale

"The research aimed at improving the way screen performance analysis is conducted using a model that accounts for most feed and design parameters in its formulation. Thus, the aim was to validate the fine screen model that was developed at the Centre for Minerals Research (CMR) unit at the University of Cape Town. Fine wet screening is increasingly becoming an important application in fine grinding operations. Minera Saucito, a lead-zinc Mexican mine has replaced hydrocyclones with eight stacks of five decker derrick screens to close the ball mill in their concentrator plant. The five decker stacks have improved the overall plant throughput by 20% and have had the ball mill circulating load reduced considerably. As a continuous plant optimization process, a number of surveys were carried out to assess the performance of the 75 µm panel aperture installed screens. The surveys were conducted at seven different feed rates to the entire nest of screens to collect performance data. Using the fine screen model to analyze the results, it is found that as the feed rate increase, the sharpness of separation reduces. The CMR fine screen model was fitted to these results. The model fits the plant data with good accuracy. Simulated results based on this model are also presented.INTRODUCTION The potential of high frequency vibrating screens has long been identified as an alternative to hydrocyclones in grinding applications (Rogers and Brame, 1985). However, high frequency vibrating screens have had two main disadvantages, low capacity and high wear rates (Kelley and Mckeon, 2005; Teknikk, 2009). Current vibrating screen technology overcomes these challenges by multiple deck screen design and use of wear resistant urethane materials for panel construction (Kelley, 2007; Valine and Wennen, 2002). For a example, the Derrick screen’s material of construction is a tensionable urethane that provide high open area ranging between 35 to 45% with considerably reduced blinding (Valine and Wennen, 2002). Thus, there has been an increased uptake by the mining industry in the use of wet fine vibrating screens closing the ball mill as the final classification stage in the comminution circuit (Barkhuysen et al., 2010; Frausto, Ballantyne et al. 2017; Pelevin and Lazebnaya, 2009; Teknikk, 2009). Even though there is a number of models in existence, none of these models adequately predict the performance of high frequency vibrating screens (Karra, 1979; Rogers, 1982; Subasinghe et al., 1990; Trumic and Magdalinovic, 2011). Recently Mwale et al., (2016) developed a model for predicting the performance of high frequency vibrating screens using the partition curve properties. The input parameters of the model include screen open area (??) in m2, tonnage feed rate (????) (tph) and the weight fraction of solids (??) in the feed for a given panel aperture size. The model was developed based on data collected from a single deck industrial size derrick screen, in a pilot setup. The work presented in this paper is an attempt to test this model using data collected from Minera Saucito concentrator, an industrial plant whose comminution circuit is shown in Figure."

Jan 1, 2018

By Cesar Gomez, Jaime Álvarez, Lisette Wen

Laboratory mechanical flotation cells are extensively used in mineral processing for running batch flotation tests with a variety of purposes, for example assessing feed characteristics, determining flotation kinetics, or testing of new reagents and procedures. It is known that the results obtained depend on the operation mode, self-aerated or forced-air, and on the operating conditions selected for the test, in particular impeller speed and gas flow rate. These different results are a consequence of changes in size distribution of the generated bubble population and its remarkable evolution when frother is added; variations in bubble size affect the bubble surface area flux (BSAF), a variable which correlates with particle collection. Results of a two-phase (air-water) test program designed to measure bubble size for a variety of combinations of impeller type and speed, gas flow rate, frother type and concentration, and cell volume, demonstrated the wide range of BSAF with which the cell can be operated. The results obtained in this work demonstrated that gas dispersion in a forced-air lab flotation machine is significantly affected by the characteristics of the impeller/cell geometry combination in use, and the operating conditions selected. Operating conditions must be carefully selected and maintained during the test to ensure consistent results, in particular when frother concentrations below 20 ppm are used, because frother concentration in the cell will decrease as flotation progresses as a consequence of frother partitioning to the concentrate.

Jan 1, 2014

By Bertil I. Pålsson, Sture V. Persson, Kent T. Tano

"Autogenous (AG) and semi-autogenous (SAG) mills often operate in an unstable state because of the difficulty to balance the rate of replenishment of large ore particles from the feed with the consumption in the charge. This has led to an increased interest in obtaining an accurate and direct measurement of mill load and the behaviour of the mill charge. A problem in attempting to measure those parameters is getting a sensor that is both robust and sensitive enough for continuous on-line measurement.Techniques that measure the force acting on the lifter when it hits the charge inside the mill have got an increased interest recently because of the ability to combine it with DEM modeling. This paper presents a method for the measurement of the apparent filling level in a pilot ball mill equipped with the Metso Continuous Charge Measurement system (CCM). In this technique a strain gauge sensor is mounted on a flat steel spring which is fitted into a recess underneath a lifter bar. In addition, a conductivity probe, the Boliden Grinding Measurement System (GMS), is mounted in another lifter bar with the purpose of comparing the two measurements. To visualise the behaviour of the charge a 2D DEM modelling technique is used with Metso HFS software.The pilot mill is a grate-discharge mill, equipped with 12 rubber lifters of square size 0.1 m, face angle 45 degrees. Steel balls in the size range 10-30 mm and density 8000 kg/m3, are used in the experiments. Test material is a hematite pellet feed, d50 around 45um, chosen to get stable grinding conditions with respect to feed size variations.The experiment is meant as a first test of the equipment’s performance, and to study how the sensors respond to changes in some operating variables. To get an understanding of, and distinguish between correlation and causality, experiments are performed according to a full factorial design with two levels, and in addition two replicates of the experiments at a center-point in the charge level setting."

Jan 1, 2003

By A. V. Abshilawa, D. G. Talakhadze, R. I. Sturua

"Processing of the tailings accumulated over the lifetime of Madneuli Copper Concentrator is an opportunity to extract additional salable copper and gold products. This paper presents a pre-concentration process for the valuable components (copper and gold) of the accumulated tailings. The developed process makes it possible to obtain a copper pyrite concentrate with a yield of 14.05%, copper grade of 1.36%, and recovery of 83.22% containing 3.78 g/ton of gold at a recovery of 84.31%. The bulk concentrate is produced by a combined process bringing together selective flotation to produce salable copper concentrate and hydrometallurgical processing of the selective flotation tailings to recover gold. KEYWORDS: FLOTATION, ALBION PROCESS, LEACHING, COPPER CONCENTRATE, SELECTION Madneuli Copper Concentrator, Georgia, was put into operation in 1975. Over its lifetime, 40 mn tons of tailings have been accumulated at the tailings storage facility (TSF). Sampling of the TSF has indicated that the average copper and gold grade is 0.23% and 0.56-0.65 g/ton, respectively. Accordingly, the TSF can be classified as a technogenic reserve. This paper discusses pre-concentration of valuable components using flotation, followed by processing of the bulk concentrate in the Albion process. Mineralogical analysis of the accumulated tailings showed that the main ore mineral is pyrite (11.71%). Copper minerals are mainly represented by chalcopyrite (0.7%). The main nonmetallic mineral is quartz (67.3%); sericite, chlorites, etc. also occur. Pyrite is present both as liberated grains and intergrowth. The absolute majority of copper minerals are found as intergrowth with pyrite, less often with quartz. Ore minerals are slightly oxidized. Chemical analysis results are shown in Table 1. Particle size distribution shows that the size class -0.2 mm - 0.045 mm has the highest grade of 0.85 to 0.97 g/ton of gold. Size class +1.25 mm has the lowest grade. Based on the chemical and mineralogical studies and particle size distribution, an optimized process was developed for pre-concentration of the valuable components prior to hydrometallurgical processing. Several gravitation, direct selective, bulk, and bulk selective flotation processes were trialed. (1,2)"

Jan 1, 2018

By Victor Avdokhin, Ivan Kovlekov

"Studies of the process of concentration of gold-containing sands and technogenic resources show that the main reason of gold losses is misbalance between size of gold particles and degree of roughness of mineral bed. This results in free circulation of small gold particles in pores with following washing off the particles from the bed by turbulent flows.We elaborated design of magnetic sluice, intended for improving efficiency of recovering fine gold by optimizing magnetic field of a magnetic system on the base of forming catching coat from magnetic mineralsThe magnetic sluice includes trough-shaped body from magnetic-conducting material. On the bottom of the trough, magnets are placed, and opposite poles of the magnets are oriented outwards. Thickness of the bottom is determined to be sufficient for locking magnetic lines of force of the magnets on each other. The magnets of rectangular plate shape are placed on the rough bottom, covering the whole surface or with spare areas; the magnets are placed across the trough with alteration of rows with the same pole orientation.Catching coat is formed of natural magnetic and weak-magnetic placer minerals in field of magnetic system of the sluice. Magnetic minerals, placing along magnetic lines of force, form rough coat of fluffy structure. Size of the magnetic particles is chosen taking into account expected size of gold particles, which are to be fixed on the rough coat or between the magnetic particles. Changing coarseness of particles of mineral bed allows to regulate selectivity of recovering heavy minerals.Forming artificial fleece from magnetic minerals of initial sand, increasing capacity of the bed and relative hydraulic proportionality of mineral particles of the bed provide for the most effective recovery of fine gold."

Jan 1, 2003

By G. M. Wolfaardt, B. C. Qi

"From a lifecycle point of view, biologically digested sludge is a valuable product that should be reused if possible. In contrast to landfill and incineration, application of digested sludge comprises the recycling nutrients and organic matter and reflects the policy of resource conservation and sustainability in waste management. Sludge may be applied to agricultural land for further sludge treatment and improvement of the characteristics of the soil. The characteristics of sludge that affect its applicability for soil conditioning include moisture content, pathogens, nutrients and metals. In this paper, the use of solid anaerobic digestion sludge of the lignocellulosic residues to condition soil was investigated in regards to nutrient composition, water content/retention capacity, hygienic quality (contamination of pathogenic bacteria) and heavy metal adsorbing/releasing characteristics of the sludge.The digested sludge had approximately 44.5% free and immobilized water and 46.9% bound water. The water-holding capacity of the sludge was high. This was the first merit to apply the sludge to agriculture in dry areas. Secondly, the sludge was rich in macro-nutrients (N, P, K) and a series of micro-nutrients (Ca, Mg, Mn, Na, Fe, Cu, Zn, B). The water-soluble fractions of macro-nutrients in the sludge were found considerably low. This implied that the loss or leaching of the macro-nutrients from the anaerobic sludge to the aqueous environment be slow. The nutrients loss owing to leaching could be reduced. However, because of a lower macro-nutrient content of the anaerobic sludge, comparable to the chemical fertilizer, it is advisable that the anaerobic sludge be applied together with commercial fertilizer to the agriculture land. Thirdly, the anaerobic sludge had strong selective adsorption affinity for heavy metal ions; non-heavy metal ions such as K(I) and Ca(II) could be released easily from the sludge in a wide pH range, such as pH from 1.0 to 8.0. Since the metal toxicity to the environment mainly comes from the mobile heavy metal ions, the selectivity to adsorb heavy metal ions of the anaerobic sludge can be utilized to reduce the availability of heavy metal ions to plants and humans in aquatic environment. Fourthly, the anaerobic digestion under thermophilic conditions showed a promising disinfecting effect to the sludge, in contrast to the landfill digestion."

Jan 1, 2003

By P. Somasundaran, G. Anastassakis, Z. Pan, D. R. Nagaraj

Gums are often used as depressants for talceous gangue minerals in the flotation of nickel and platinum bearing ores. However, the mechanisms of gum adsorption on talc are not clearly established. In this work, adsorption of guar gum at the talc-solution interface is investigated using spectroscopic and allied techniques. Guar gum adsorption on talc is not affected significantly by changes in solution conditions such as pH and ionic strength. Electrokinetic studies showed that guar gum decreased the negative zeta potential of talc but did not reverse the charge. Fluorescence spectroscopy studies conducted to investigate the role of hydrophobic bonding using pyrene and dansyl probes showed no evidence of the formation of hydrophobic domains at talc-aqueous interface. Urea, a hydrogen bond breaker, reduced the adsorption of guar on talc to the same extent as that for guar/alumina system, in which hydrogen bond plays an important role. All of the above results suggest that one of the main driving forces for guar adsorption on talc is hydrogen bonding rather than electrostatic or hydrophobic force.

Jan 1, 2003

By C. Y. Sun

Flotation of chalcopyrite and unactivated malachite with xanthates (ethylxanthate, butylxanthate, octylxanthate and dodecylxanthate) is studied in this paper. Minerals interacted with xanthates are detected by FTIR, and simulated by molecular mechanics. It shows that chalcopyrite can be floated with 4 kinds of xanthates, and unactivated malachite can?t be floated with ethylxanthate but can be floated directly with later 3 kinds of xanthates while characteristic absorption peaks of those four kinds of xanthates are all detected by FTIR on chalcopyrite and malachite surface. After simulating the interaction between xanthate and mineral, it shows that H2O and OH-can interact with chalcopyrite and malachite, and their interaction energy may be so called energy bulwark which must be overcome by collector when collector interacts on minerals; the two sulfur atoms in xanthate group interact with copper and neighbor iron atoms on chalcopyrite. It also shows that molecular mechanics results with logP of collectors can interpret the mechanism of xanthate-mineral on atom scale.

Jan 1, 2014

By A. Usov

The studies carried out by the Russian researchers and those carried out jointly within some contracts with scientific organizations and companies of other countries, show that the electric pulse disintegration of materials (ED), proposed and investigated in detail in Russia (Kalyatsky, et al, 1980; Usov et al, 1987; Semkin et al, 1995; Usov and Tsukerman, 2000; Kurets et al, 2002) has been widely recognized and developed abroad (Andres, 1995; Inoue et al, 2000; Biela et al, 2008). The Russian and international journals and the proceedings of the conferences dealing with the electric pulse disintegration pay great attention to the principal principals of selective disintegration of materials. There is no, however, any information concerning both the technical means developed to implement the technique and the assessment of their performance, which would be necessary in objective assessment of the industrial use of the technology. The results of long-term studies of the technique and technologies of electric pulse disaggregation by research institutes such as Research Institute of High Voltages (Tomsk), Kola Science Centre of RAS (Apatity), Institute "Mekhanobr"(S.Pertersburg) described. Exploratory stands and technological installations are developed to carry out pilot tests and operations under production conditions. Basic circuits and classification of technical means electric pulse disintegration of the materials are proposed, the analysis of transportation schemes and classification of the material in the disintegration apparatus are given, construction of chambers for continuous stadial disintegration of ores and materials are presented. The features and technological efficiency of electric pulse disintegration of various types of ores, and the spheres of effective use of the method have been determined. Keywords: electropulse disintegration, disintegration machines, chambers of comminution, stadial comminution.

Sep 1, 2012

By I. N. Gridasov, T. V. Ignatova, E. V. Shelepov

"Mikhailovskoye Deposit is comprised of oxidized ferruginous quartzites among other minerals with the former widely spread across the ore field and mined along with unoxidized ferruginous quartzites. PJSC Mikhailovsky GOK strategic development is aimed at iron ore product output expansion. The most critical item of the strategic development road map is process design for separation and concentration of hematite contained in oxidized ferruginous quartzites mined as the by-product in the open pit. Laboratory and semi-industrial tests run to design cost-effective, reliable and environmentally friendly process for Mikhailovskoye deposit oxide quartzites processing included the following processes: - pilot tests of reverse anionic flotation which produced concentrate with Fe60.1-62.9% total iron content and 66-69%Fe recovery rate; - combined magnetic separation and flotation (Marubeni Company, 1982) including slime removal, reverse anionic and cationic flotation and high gradient magnetic separation resulting in 48.9% yield, Fe55-57.5%, up to Fe60.5% hematite concentration ( Fe64.1% being the best result achieved),76.2% recovery. - magnetic separation and flotation, including separation in low gradient (1400 Oe) and high gradient (up to 17000-18000 Oe) magnetic field. The results of these pilots tests were the following: 57-59%Fe concentrate, 70%Fe recovery (Mekhanobrchermet, MGOK, 1982-1988): - magnetic roasting in pilot plant of TSGOK (Krivoy Rog) which produced 61.1%Fe concentrate with 81.5% recovery. Major disadvantage of the method is high generation of dust equal to 20% of the initial feed. Based on third-party studies flotation of oxidized ferruginous quartzites process embracing best processing methods was designed by Metalloinvest Management Company LLC and PJSC Mikhailovsky GOK engineers. This paper discusses analysis of studies aimed at intensification of separation processes with application of mechanical slurry agitation (MSA), addition of alkali (NaOH) and elutriation of initial feed. The paper also provides a design solution to implement a lab-scale MSA plant. It includes feasibility evaluation of MSA inclusion in flotation of oxidized ferruginous quartzites process to enable higher yield and hematite recovery in resultant concentrate. Outcomes of the discussed work have significant value for prospective engineering of OFQ concentration process."

Jan 1, 2018

By Dmitriy Makarov

The paper presents the modeling and analysis of oxidation of pyrite copper-zinc ore samples from the Letnee, Yaman-Kasy and Valentorskoye deposits. It is found, that the oxidized samples contain copper and zinc sulfates that are leached under the sample and water contact. It is shown, that sulfide floatability is decreased by the longer-term oxidation.We advise to improve nonferrous metals recovery by joint leaching and ultrasonic treatment of oxidized compounds. Study of the geotechnological processes of non-ferrous metal extraction, on the basis of two copper-zinc ore deposits shows, that heap leaching is of little use for the ores of the Letnee deposit. Leaching results for the Yaman-Kasy ore showed more promise.

Sep 1, 2012

By V. E. Dementiev, V. I. Kulikov, G. I. Voiloshnikov, Yu. O. Fedorov

"The report presents the summary of the JSC Irgiredmet’s activities in the field of preconcentration of ores. As of 2018, the Institute has almost 40-years’ experience in this area. Over the years, Irgiredmet has done a lot of work – from development to implementation of new technologies of ore piece sorting and concentration based on X-ray radiometric separation (XRRS). INTRODUCTION Preconcentration has been a challenging issue of the mining industry over the last decades. The implementation of this technology can significantly increase mining efficiency. The main application of preconcentration is improvement of mined ores quality, however new and more complex issues have arisen with the evolution of the technology. Irgiredmet has started to develop an efficient preconcentration technology for gold-bearing and rare-metal ores 40 years ago. The X-ray radiometric method widely used at that date as a method of elements determination in geology and geophysics become the ground for this work (1). Since that time, the Irgiredmet Institute has developed and significantly improved the technology of piece ore sorting, or XRRS (2-5), that is currently also known as the X-ray fluorescence method. The progress of the XRRS development achieved by Irgiredmet in cooperation with Rados LLC, Tekhnoros LLC (Krasnoyarsk), Rados-Service LLC and CJSC Tekhnogen (Ekaterinburg) has proved efficiency and applicability of the XRRS technology for processing a wide range of minerals and solving of various technological problems (7-9) compared to other radiometric methods (6). Furthermore, obtained results are supported by numerous studies, trials and implementations. The significance of ore preconcentration for greenfield and brownfield projects determined the establishing a new subdivision of Irgiredmet, the XRRS Technology Center (XRRS TC), that has provided the Institute with a completed range of processing technologies, from preconcentration to producing final products. Over the past few years, the XRRS Technology Center has carried out studies and testing of a numerous (more than 100) projects, mines and deposits of gold-bearing ores, rare metal ores (Be, Ta, Nb, W, Mo), base metal ores (Cu, Sb, Zn, Pb), ferrous metal ores (Fe, Ti, Cr), rough diamonds and coal. The XRRS Technology Center performs various specific studies and testing not only in Russia, but as well as in Kazakhstan, Georgia and Mongolia. Mines and companies from Chile, India, China, Iran and other countries also take an active interest in the XRRS technology."

Jan 1, 2018

By M. Evertsson, E. Hulthén

"In aggregate production and mining the operators are responsible for controlling and monitoring the process to maintain high plant throughput and safe operation. Operators have to make different decisions to control the process due to changed demand on the operation from both management and conditions of the process. The quality of the response and the time it takes for an operator to respond to altered demand relies on what information is available and the experience of the operator. In this work a dynamic simulation platform has been developed to be used for operator training. Models for representing production units and process control for plant simulations have been developed and implemented in MATLAB/SIMULINK to simulate time-dependent plant behavior. Stochastic and scheduled events are included using the discrete events simulation toolbox SimEvents. The human-machine interface was developed using the human-machine interface software ICONICS. The operators’ cognitive process, in interpreting the plants semantic, has been studied by observations and with informal interviews with operators. This was done to get information about the daily operation and the problems that occur in the process. By interacting with operators that experience different physical interactions with the process; more qualitative e-learning software for supporting operator training in a dynamic operator environment could be developed. The quality of the operator training environment was evaluated with a usability study that was performed with operators and others within the production."

Jan 1, 2014

By D. Z. Wei

Amine collectors with different structures and length of carbon-chain have been widely used in oxide minerals flotation. In this paper, we synthesized one kind of binary amine, N-dodecylethyl- enediamine, and studied its flotation performance. From the results, we can see N-dodecylethylenediamine which has excellent frothability, is a new type of chelating surfactants. And it also has fine catchability to quartz and hematite. The recoveries of quartz and hematite increase with the augment of N-dodecylethylenediamine concentration. When the dosage of collector reaches 100g/t, the recoveries of quartz and hematite achieve 95.30% and 87.89% respectively. Meanwhile, the influence of pH on the flotation recovery of hematite is studied and test results showed that, as pH increases, the flotation recovery rises until pH=9. And the recovery reaches its maximum in alkalescence. The collector has better flotation capability to quartz than to hematite. And the maximum recovery of quartz is gained in alkaline media, which reaches 97.87%. Finally, the flotation mechanism of N-dodecylethylenediamine is discussed through the measurement of infrared spectroscopy.

Jan 1, 2014

By Narasimha Mangadoddy

The complex nature of multi-phase flow in dense medium cyclones has restricted plant operators and designers to rely on empirical equations for predicting the performance. A number of empirical cyclone models have been developed in the past (Wood, 1990; Dunglison, 2002). In recent years, this subject has been broached with computational fluid dynamics (CFD). Most of the CFD models have not considered the correct rheological behavior of magnetite medium while simulating the medium segregation inside the cyclone. These models mostly predict excessive underflow volumetric flow rates. In this paper simulations of magnetite medium in a dense medium cyclone, were conducted in FLUENT where the particle phases were simulated using the modified Mixture model. The turbulence was resolved using Large Eddy Simulation (LES) model. The rheological behavior of medium was considered in the form of Granular viscosity, Newtonian and Non-Newtonian models corrected with particle loadings and fraction of ultrafines. Multi-phase simulations using granular viscosity option although predict the overall split product medium densities reasonably close to experiments, the mixture viscosity values are restricted to substantially lower values, similar to water viscosity. Simulations using Newtonian viscosity model corrected with particle loading, and fine fraction below 53µm size is predicting overall mixture viscosity levels well over water viscosity levels, but under predicting the under flow the underflow medium density. Multi-phase simulations using Non-Newtonian Herschel-Buckley model, calibrated for superfine magnetite medium measured viscosities, is closely predicting the medium segregation with gamma ray tomography data. Overall predicted product medium densities, underflow volume split are close to the experimental data. This model is can be further used to simulate coal portioning and hence in developing new designs.

Sep 1, 2012

By R. Bugueño, W. Calderón, G. Montes-Atenas

From the point of view of industrial performance of metal extraction, the efficiency of a column leaching operation depends strongly on the leaching agent and the ore properties such as mineral composition, mineral liberation and particle size distribution. One aspect that has become particularly important is how the leaching solution flows through the porous structure which contains the valuable minerals. It is known that the output flow rate of leaching solution depends mainly on factors of the input flow, environmental condition and porous bed properties. The latter factor is often evaluated and reported under saturated conditions but in practical leaching systems unsaturated conditions are dominant. This investigation has the purpose of determining the residence time of the leaching solution in columns with different diameters under unsaturated conditions by using experimental data and numerical simulations. Laboratory leach test were performed using isothermal jacketed columns with top cap to reduce the evaporation. The simulations were performed using the software SVFlux® which incorporates material properties such as Soil Water Characteristic Curve (SWCC) and Unsaturated Hydraulic Conductivity. Preliminary results indicate a non-linear asymptotic behavior of the saturation rate with respect to the operation time. Results from numerical simulations show the same non-linear behavior and a considerable delay between input and output flows. Further analysis concerning with the effect of transpiration and evaporation mechanisms is discussed.

Jan 1, 2014