Search Documents

By Yuexin Han, Jie Liu, Shuai Yuan, Yanjun Li

"In order to improve recovery efficiency of iron minerals from iron ore tailings and to reduce its connected environmental pollution, this article investigated the reducing roasting of iron ore tailing in a laboratory fluidized magnetization roasting reactor to optimize the roasting method and conditions. The examined parameters included roasting temperature, roasting time and reducing atmosphere. The parameters evaluating magnetizing roast efficiency and theoretical value were determined. X-ray diffraction (XRD) analysis was used to investigate the conversion of iron phase after roasting. The results show that the best magnetizing roast conditions are roasting temperature of 540?, holding time of 15min, and CO concentration of 20%. The magnetization conversion ratio of roasting products is over 80%, under the best magnetic separation condition, the concentrate grade of iron is 65.61 % and the recovery of iron is 83.77 %. The XRD analysis shows that Fe exists in hematite and siderite before roasting and exists in magnetite after roasting. The technique not only recovers the iron minerals from tailings with good economic benefit, but also reduces the environmental pollution of tailings accumulation.INTRODUCTION Iron ore tailings are the solid wastes generated during the beneficiation process of iron ore concentration and are one of the main pollution concerns in the mining industry (Das et al., 1996). Continuous development of the iron and steel industry has led to the increasing amount of iron ore tailings; there are over 300 million tons of iron ore tailings discharged per year (Rao et al., 2016). The huge amount of stockpiled iron ore tailings brings a series of environmental and social problems. Comprehensive utilization of iron ore tailings can not only reduce environmental load but also conserve resources, promoting sustainable development of the society. In recent years, iron ore tailings as secondary resources have received considerable attention in many countries in the word and numbers of studies on utilization of iron ore tailings were carried out, such as recycling the valuable minerals (Datta et al., 1996; Jia et al., 2013; Panda et al., 2018), used in construction material compositions as alternative source of raw materials (Das et al., 2012; Zhou et al., 2012; Luo et al., 2016) and other utilization. The iron minerals were recovery by magnetization roasting (Rao et al., 2016; Yang et al., 2013; Yang et al., 2011) and flotation (Kumar and Mandre, 2016). By comparison the reduction roasting has more advantages, but it was found that the conventional roasting equipment was inefficient, high energy consumption and un-economically applied on an industrial-scale."

Jan 1, 2018

By C. L. Tang

Parts of the wastewater are reused directly and the rest moderately purified and reused, so the utilization rate of wastewater of the whole processing plant reaches 100 percent. At the same time, beneficiation indicators have been improved stably, and great economic and social benefits have been achieved.

Jan 1, 2014

By Priyanka Dhar, Kurt Aasly, Hanumantha Rao Kota, Hassan Bouzahzah, Maria Thornhill

The interest in investigating the processing characteristics of mineral deposits in Norway has seen an upsurge in the last decade. One of the major areas of interest is a huge copper deposit, operated by NUSSIR ASA located in the Repparfjord Tectonic Window in the caledonides of west Finnmark. This study reports analysis of ore from the deposit for development and modifications in the flotation flowsheet for the NUSSIR ASA copper ore. The mineralogical characterization for the ore sample was achived by optical microscopy and Zeiss automated mineralogy while grinding characteristics were tested using Bond Index tests. The results confirmed the presence of Cu minerals in the form of chalcocite, chalcopyrite and bornite in the samples, which are mainly liberated in the – 105 µm size range. The majority of non-liberated copper sulphides associated with silica and the carbonates varies from 3 to 28 percent in the –250 µm samples . It is also observed that the copper minerals are uniformly distributed in all size ranges. Selective flotation of NUSSIR copper ore was performed in different size fractions with a motive to identify the correct liberation size and thus to obtain a copper concentrate meeting the quality requirements. The flotation experiments are essentially performed in two stages: the rougher and the cleaner stage. Mass balance calculations were performed showing that approximately 88 percent of copper can be obtained at the end of the process. Ultimately, overall circuit copper recoveries ranged between 83.5 to 88.1 % with a concentrate grade of 35 to 48 % Cu.

Jan 1, 2018

By C. Han

The analytical results of Dagushan grinding workshop primary grinding operation product show that the size fraction of -0.079mm is 32.88%, the size fraction of -0.01mm is 9.97%, the rate of -0.01mm size fraction and -0.079mm size fraction is 30.32%. It means that there is too much -0.01mm size fraction in primary grinding operation product and fall out that there will not be a better result in following operations. Several tests have been carried out to control the size distributing of the primary grinding operation product according to confirm the appropriate conditions of grinding operation. Integrate with theoretic count, grinding property tests show that the appropriate rev ratio of ball mill should be between 85% and 90% so as to get better size distributing. Based on the results of grinding property tests, the shocking property tests simulated the momentum of different diameter steel balls in the ball mill have been carried out. It showed that if want to get better size distributing the appropriate diameter of steel ball should be 110mm. The tests result shows that regulate diameter of steel ball and rev ratio of ball mill could control the size distributing. Contrast to the technical parameters of ball mill in grinding operation now, there are some significant advices are given for practice and industrial tests.

Jan 1, 2014

By Lina Chica, Arturo Barrientos, O. Bustamante

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

Jan 1, 2014

By Chiharu Tokoro

Acid Mine Drainage (AMD), high acid water containing heavy metals discharged from mines, has been recognized as major cause of mine pollution. In Japan, the government spends billions of yen every year to prevent pollution caused by AMD in about 80 abandoned mines. It is widely recognized that the treatment could continue for long decades or an even century. However, costs and environmental loads are uncertain during the treatment because a predictive model for the quality of AMD, the dosage of neutralizer, and the amount of sludge that is applicable for abandoned mines with limited data has not yet been established. In this study, a two-steps predictive model for solution composition and neutralization chemical requirements of AMD in future was constructed based on the geochemical modeling. Requisite input data of the model was the past historical water quality data from AMD monitoring, such as metal concentration and pH in the solution, instead of the sample rocks as other conventional prediction methods. In the first step, solution composition of AMD in the future was extrapolated from the available historical data using geochemical simulation considering the first order kinetics for the mineral dissolution. In the second step, neutralizer dosage and sludge generation in the future was predicted based on the geochemical simulation supposing the chemical equilibrium and oxidation state for all of elements in the solution. Based on case studies of two abandoned mines in Japan, solution composition, neutralizer dosage and sludge generation were estimated. The results of this study demonstrate the effectiveness of our model for the prediction of AMD quality and chemical requirements of neutralization treatment after mine closing. The model is useful for the estimation of the neutralizer dosage and the sludge volume in abandoned mines with limited data. Keywords: acid mine drainage, predictive model, geochemical modeling, first order kinetics, water monitoring

Sep 1, 2012

By Y. Foucaud, I. Filippova, L. Filippov

Flotation is the most common beneficiation route for tungsten ores, but the predominance of minerals with similar surface properties poses a real challenge. This study investigates the use of Falcon centrifugal separators for gangue minerals removal and desliming prior to flotation. A typical tungsten-bearing skarn ore (Tabuaço, Portugal) is used, containing scheelite (CaWO4) associated with dense calcium-bearing silicates (vesuvianite), fluorite, apatite and light silicates (feldspars) as gangue minerals. Two types of Falcon bowls (Falcon UF and Falcon SB) were used, prior to flotation tests with fatty acids as collectors and a combination of sodium carbonate and sodium silicate as gangue minerals depressants. This flowsheet was compared with a reverse configuration, using flotation prior to Falcon concentrator, and with a classical flowsheet, using hydrocyclone and flotation. Gravity pre-concentration and desliming with the Falcon concentrator were optimized through the design of experiments (DoE) methodology. The influences of pulp density, rotational speed, feed flowrate and fluidisation pressure (for the Falcon SB) were studied for both bowls. Results showed that the Falcon can be used as a desliming and pre-concentrating apparatus. Separation performances depend mainly on rotary speed and pulp density for the Falcon UF, whereas rotary speed and fluidisation pressure are the main parameters for the Falcon SB. With only one stage of Falcon SB, an enrichment ratio of 7.9 is obtained with a 65% WO3 recovery while 89% of apatite and fluorite are rejected, which constitutes a very good selectivity. In comparison, Falcon UF shows lower enrichment ratios, around 2.7. In terms of desliming, Falcon UF is as efficient as the hydrocyclone, while the Falcon SB is significantly more efficient. Hence, the use of Falcon SB prior to flotation improves the overall performance of the tungsten flotation route by desliming the flotation feed while pre-concentrating the scheelite. It impacts very advantageously the flotation, as most of the calcium-bearing minerals are eliminated. A Falcon SB stage prior to flotation yields a final concentrate grade of 29.7% WO3 with a recovery of only 36.8 % that should be optimized as the reagents dosages were not adapted to the pre-concentrated feed.

Jan 1, 2018

By M. McClintock

"High Pressure Grinding Rolls (HPGR) is increasingly being chosen for comminution circuits for its energy-efficiency for hard rock mining operations. Despite HPGR’s growing popularity, geo-metallurgy programs are still prohibitively expensive because of large sample requirements. Traditionally, sizing HPGR application requires a significant amount of sample, in the order of 1 to 10 tonnes, depending on the level of study and complexity of the resource. Therefore, engineering and design of HPGR circuits typically are reliant on few composites that are required to be representative of the resource and mine plan. Three bench scale HPGR test methodologies were developed in 2015 at NBK Institute of Mining Engineering at the University of British Columbia (UBC) capable of defining the energy size breakage relationship of pilot HPGR. These methodologies were developed to allow bench scale testing for different levels of study from PEA (Preliminary Economic Assessment) to detailed design and operations. The Piston Press test defines the energy size reduction relationship by measuring specific energy consumption and corresponding feed and product size distributions. The advantage of Piston Press testing is the small sample requirement of 5 to 10 kg. Small sample requirements allow multiple samples to be tested across a deposit. Piston Press testing allows extensive geo-metallurgy programs that can determine ore variability and inform in optimization and production planning. To date, the Piston Press methodologies have been validated on a pilot-scale HPGR unit located at UBC. Recently, testing was conducted to calibrate and validate the Piston Press test against full-scale HPGR on a gold sulphide ore deposit. The program included the collection of operational data with the respective HPGR feed and recycle sample. Sample collected was used both for Piston Press testing and HPGR piloting. This paper discusses the test-work and results as carried out during this program, using the aforementioned methodologies."

Jan 1, 2018

By Francisco Cubillos, Jorge Menacho, Cesar Gomez, Juan Rodríguez

Mineral flotation is the most used process to selectively separate particles of one or more minerals of interest. The process uses natural or induced hydrophobicity to collect particles on the surface of rising bubbles through collisions and formation of bubble-particle aggregates. Flotation machines must keep particles in suspension and well distributed, while at the same time, disperse a mass of air into a population of small bubbles. The efficiency of the separation depends primarily on the characteristics of the bubble population generated in the machine and its distribution and flow throughout its volume. The formation and separation of bubble-particle aggregates create two zones, with strong interactions between them, and with markedly different hydrodynamics conditions. A model describing two-phase hydrodynamics of the continuous and dispersed phases (frother solutions and bubbles, respectively), moving along the whole unit, is proposed. Bubble populations are characterized at the formation stage including the effect of the presence of frothers. Flow through the aggregates formation zone, where bubbles move freely and are closely spherical, is modeled using drift-flux analysis. In the aggregates separation zone, bubbles initially pack maintaining a water layer thick enough to prevent capillary forces to affect their shape. As water drainage proceeds, bubbles deform, capillary channels form, and a network of channels with a diameter size distribution develops; channels become narrower (permeability is reduced) as the distance from the interface increases. Froth hydrodynamics is characterized using models originally developed to describe unsaturated flow through porous solid particle beds. Effects of hydrostatic pressure are considered.

Jan 1, 2014

By K. D’Elia, L. D. Ogrel, O. A. Malyshev, T. I. Yushina, I. M. Petrov

"The purpose of this research is to develop enhancements in the mineral processing by flotation methods of nonferrous ores. Currently, 180-190 million tons of ore are processed by flotation in Russia. The annual processing volume of copper-nickel and copper-zinc ores exceeds 20 million tons. In the total volume of processed ores by flotation, non-ferrous ores account for roughly 35% and ores of precious metals for another 15%. The total demand of flotation reagents in Russia in 2016 was estimated at 170,000 tons. Sulfur-based collectors used in the flotation of non-ferrous sulfide ores (typically, xanthates) do not always offer sufficiently high recovery of valuable components.It has been found that reagents like DMIPEC and DK-80 improve the recovery of metals into concentrates. To identify the reasons of that higher recovery, quantum chemical calculations of the mechanism and interaction forces of DMIPEC with non-ferrous sulfides were undertaken by determining the stabilization energy of the resulting chemical complexes. It has been shown that, in the interaction of DMIPEC and DK-80 with the surfaces of sulfide minerals, ethylene and acetylene bonds act as the reaction centers, and the formation of molecular p-complexes is the result of metal-cation interactions with the surface and the flotation reagents.In the flotation of non-ferrous ores, DMIPEC and DK-80 act as selective supplementary collectors with foaming properties, and at a flow rate of 3-35 g/ton, they reduce the flotation time, and increase copper recovery by up to 3.5%, zinc recovery by up to 12%, gold recovery by up to 8-10%, allowing to increase the recovery of valuable components by 1.5-12.0%, basically this kind of reagents nearly double the flotation rate, improve the grade of the concentrate, improve the stability of the flotation process parameters, and reduce the environmental impact of flotation plants."

Jan 1, 2018

By Peter Ay, Bodo Müller, Jens Markowski, Manfred Kanthak, Florian Logsch

"Presently the global commodity situation for non ferrous-, precious- and rare metals is characterized by a strong increase in consumption and a simultaneous shortage of materials derived from primary sources. So the use of secondary raw materials gains is important due to economic and ecological reasons. Non Ferrous-, precious- and rare earth metals were detected in household waste (Municipal solid waste, MSW) for years. In MSW-treatments plants NF-metals are actually mostly separated from dried fractions. The separation of these metals is carried out with the aim of removing particles which disrupt further processing. A selective enrichment of individual non-ferrous metals has not been carried out previously. The separated fractions contain mixtures of Al, Cu, Zn, Pb, Sn, alloys, precious metals (e. g. Au, Ag, Pt) and rare metals (Ga, In, Nd etc.) along with considerable amounts of contaminations. The R&D project "NE-Rec" selectively processes the coarsely separated non-ferrous-metal-conglomerates increasing the concentration of targeted metals. Metals and metal mixtures are concentrated by sorting steps and the impurities are discharged from the process. Still contaminated precious metals are then subjected to a wet-chemical treatment. So metals can be specifically brought into solution or can be precipitated to separate unwanted components (inerts, polymers, foreign metals). Further the relevant metals will be concentrated by thermal-metallurgical processes. The technology, developed in the R&D project, enables identification, separation and processing of non-ferrous metals, precious metals and REM in household waste and transfers them into further processable individual fractions."

Jan 1, 2014

In this paper, the recovery of copper minerals and molybdenite in the rougher/scavenger banks of two separate mineral processing plants is compared with recovery in laboratory (batch) cells. A number of metallurgical surveys were conducted in two plants treating porphyry copper and molyb-denum ore. Batch flotation tests were performed on plant conditioned flotation feed slurry, in parallel with the plant metallurgical surveys. The effect of flotation feed density on recovery of copper minerals and molybdenite in the plant and batch laboratory cells was investigated. Changes in flotation pulp density had little effect on copper mineral recovery, in both plant and laboratory cells. The ultimate recovery for molybdenite, on the contrary, increased considerably when the pulp density was reduced, both at plant and laboratory scale. Recovery of copper minerals in the plant and laboratory cells was comparable, while molybdenite recovery in laboratory flotation cells was 3%~13% higher than in plant. It is hypothesised that the flotation rate of molybdenite is sensitive to cell hydrodynamic conditions (i.e. local turbulent energy dissipation) more than the flotation rate of copper. The flotation behaviour of molybdenite particles is likely to be predominantly controlled by bubble-particle collision frequency, which is enhanced in high local turbulent energy dissipation environment. For chalcopyrite, the flotation recovery is mostly determined by attachment and stability efficiencies. An increase in local turbulent energy dissipation, while increasing collision efficiency, may negatively impact on attachment and stability efficiencies. The outcomes may have a considerable impact on increasing molybdenite recovery from porphyry ores.

Jan 1, 2014

By B. K. Gorain

Mining of low grade deposits along with the necessity to design and operate flotation plants with high throughput presents unique metallurgical and environmental challenges that need to be addressed to reduce project risks, improve project economics and to sustain the profitability of operations over the life of a mine. Some of the key challenges include poor recovery of valuables and concentrate quality issues due to complex mineralogy, the need to use poor quality water such as brackish or sea water, reduce environmental impact from the process, integrate flotation with hydrometallurgy to maximize precious metals recovery, escalation of capital and operating costs, use of unproven technology and constant use of larger equipment, high ore variability, worldwide constraints on resource availability and an ever increasing need for reliable metallurgical input to financial models to evaluate economic viability of projects. The need to develop effective solutions to these problems in a short time frame is becoming a key to the success of any new project and for sustaining the profitability of a mining operation. An integrated multi-disciplinary approach to problem solving is crucial with the need for a more lateral thinking along with strategic partnerships and collaboration involving the right players. This paper presents some of the key findings based on experiences from a large number of challenging projects and operations focused on solving complex flotation problems Keywords: mineral processing, flotation, flotation problem solving, flotation optimization, plant design, innovation

Sep 1, 2012

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 Yuhua Wang, Huilan Yang, Yanqing Jiang, Dongfang Lu

"Generally, the concentration of bauxite flotation tailings is around 10%, a large amount of water in tailings needed to be recycled in the flotation process. Sedimentation and dewatering properties of tailings were investigated under different conditions. Surface high negative charges on mineral particles are the key factor to destroy the settlement of tailings when the pulp pH is around 8.9. Hence, the modification of pulp pH around 7 is necessary to the diminution of the repulsive force between mineral particles and then the acceleration of sedimentation of tailings. Anionic polyacrylamine with molecular weight of 14 million is the best flocculant for the settlement of tailings in all tested polyacrylamines. P-toluene sulfonic acid shows better properties than hydrochloric acid for pulp pH adjustment when anionic polyacrylamine with molecular weight of 14 million is used as flocculant. Although the flotation of diaspore is depressed in the presence of polyacrylamine using sodium oleate as collector, but the recycling water traded by the combination of ployacrylamine and p-touenesulfonic acid does not show the depression effects on the flotation of bauxite ore. The lower residual content of polyacrylamine in recycling water treated by the combination of ployacrylamine and p-touene sulfonic acid plays an important role. INTRODUCTION Generally, the waste water generated from mineral processing plant is usually treated by sedimentation, oxidization, electrodialysis, ions exchange, active carbon adsorption and flotation technology, and the treated water is also used again in the industrial process. Flotation was adopted widely to improve the quality of bauxite from low grade diasporic bauxite in China. For flotation, the grinding fineness of bauxite is over 90% -0.074 mm, sodium carbonate and sodium hexametaphosphate were used as regulators, so the tailings pulp is very difficult to settle and be dewatered (Y. Wang et al., 2004; Y. H. Wang et al., 2007; Wang Yu-hua et al., 2008; Wang Yuhua et al., 2011). The water recycling of bauxite tailings are becoming the highlight for the industrial application of the flotation process for bauxite ore. Researchers in China shift their attentions onto this topic."

Jan 1, 2018

By Kari Moen, John Rasmus Leinum, Jarle Hjelen, Terje Malvik

"Automatic identification and characterisation of mineral raw materials and beneficiated products are of major importance in mineral processing. However, minerals show great variety in their composition and physical and chemical properties. Industrial minerals may contain the same elements in about the same amount. In these cases backscatter electron imaging or chemical analysis are not sufficient to identify the minerals. Another problem arises when micro textures are not detectable in traditional imaging or the grain size is smaller than the X-ray spatial resolution.As a supplementary technique in these cases, application of crystallographic information by electron backscatter diffraction (EBSD) in the scanning electron microscope (SEM) may be a suitable method. By means of EBSD, diagnostic mineral information can be achieved if indexible patterns are provided.Until now EBSD has not been used frequently on geological samples for mineral and micro structure discrimination.The technique has been demonstrated on three Norwegian mineral raw materials and one Italian marble and shows that it has some advantages compared to traditional techniques."

Jan 1, 2003

By Ray Everson, Henry Kasaini

"We carried out adsorption experiments in chloride media to study the adsorption characteristics of Pd (II) anions on the surface of activated carbon. Throughout the experiments, we used commercial activated carbon pellets (0.8 Norit). The adsorption process was interpreted by using the ionisation and adsorption model. This implies that palladium anions were adsorbed physically on a protonated surface of activated carbon either as anionic complex species (PdCl4 -2) or aqua chloro-complex species [PdCl3(H2O)-] in acidic media. Furthermore, we established that adsorption of Pd (II) species was reversible at high chloride [Cl-1] concentration. The maximum adsorption capacity (Qsat) of Pd (II) anions averaged 27 mg/g. The Toth adsorption isotherms fairly predicted the equilibrium adsorption of Pd (II) species and the associated surface coverage.The effect of temperature and acid strength of the feed solution on the adsorption of Pd (II) ions were quantified. The adsorption kinetics was limited by external mass transfer since the effect of pore diffusion on the overall rate constant was negligibly small. A pseudo first-order kinetics model was used to describe the adsorption kinetics."

Jan 1, 2003

By E. V. Zelinskaya

"Mineral and industrial raw material mining and preparation make a negative impact on the environment. The main types of impact are the land resources gathering, soil and water balance disturbance, surface-water, underground space and atmospheric air pollution, as well as the vast amount of solid and liquid waste production. Considerable attention in recent decades has been given to waste recycling. The task is to maximize the use of both newly formed and accumulated solid and liquid wastes. The mining and mining and smelting enterprises industrial waters are a very promising source of secondary hydromineralic raw materials. They have high concentrations of not only calcium, sodium, but also, for example, lithium, rubidium, heavy non-ferrous metals. In general, unfortunately, we have to state that today there is no wide practice of extracting valuable components from waste enrichment, as well as processing of man-made waters to extract metals from them. The quantity of extracted components from underground, and furthermore passing waters, is insignificant. At the same time there is a tendency to increased demand for rare metals: Sr, B, Br, I. This is explained by their wide use in many industries. For example, the consumption of lithium products is steadily increasing. The obtained results showed that in the liquid phase in connection with high salt content and a significant difference in the macro- and microcomponents contents, conditions are initially created for the microcomponents selective isolation possibility. The identified conditions realization is most possible in such technological processes as cryotechnology, sorption and ion flotation. There is an urgent need to expand research in this direction and to recognize as a publicly important task the mining and industrial waste processing full-scale introduction into the practice of operating mining and processing enterprises and iron and steel companies.INTRODUCTION Mineral and industrial raw material mining and preparation make a negative impact on the environment. The main types of impact are the land resources gathering, soil and water balance disturbance, surface-water, underground space and atmospheric air pollution, as well as the vast amount of solid and liquid waste production."

Jan 1, 2018

By V. F. Petrov, O. D. Khmelnitskaya, V. M. Lodeischikov

"The processing of copper gold ores is one of the major issues of gold-mining industry in the beginning of 21st century. In this case, application of ammoniacal cyanidation process for this type of mineral raw materials deserves special attention. Irgiredmet Institute has carried out a wide range of studies on ammoniacal cyanidation process and evaluated the possible commercial use of this process for Russian operating plants. Copper gold-bearing ore from a current Russian deposit was studied. The content of gold and copper in the ore is 9.4 g/t and 0.4%, respectively. Based on the results of preliminary test work, a flow sheet was developed. It included gravity concentration followed by cyanidation of the gravity tailings using CIP. The flow sheet provides sufficient total gold recovery (91.5%). However, this technology has disadvantages, such as high specific consumption of reagents: 4.5 kg/t NaCN and 13.5 kg/t Ca(OCl)2 the ore and the increased gold grade in the liquid phase of the tails slurry (0.2 g/t). In order to improve cyanidation process parameters, test work on gravity tails processing using ammoniacal cyanidation was carried out. After the test work was completed, ammoniacal cyanidation flow sheet for copper gold-bearing ores was developed. Leaching conditions were optimized using recycled process solutions. Recommendations on gold recovery from the solutions and tails detoxification are given. The proposed flow sheet provides 91.5% gold recovery. In this case, compared to the conventional option, the consumption of cyanide decreases by 3-4 times.INTRODUCTION The technology of precious metals recovery from gold-bearing ores is based on cyanidation. This accounts for up to 90% gold recovery and the significant portion of silver (Lodeischikov, 1999). However, there exists the category of so called refractory ores. They are not amenable to direct cyanidation (without using additional expensive processes), or they are characterized by low indices of metals recovery and high consumption of reagents. The latter also include copper gold ores. Their deposits can be found extensively both worldwide and in Russian Federation. A feature of these ores is that they contain not only gold but also copper. It is considered not only as a valuable component but also as a harmful mineral impurity that hinders gold cyanidation, gold precipitation from the solutions by cementation onto zinc dust and adsorption onto activated carbon (CIL, CIP-processes), detoxification of cyanide bearing effluents."

Jan 1, 2018

By Kumar Ranjan, Kumari A. V. Asha, G. E. Sreedhar, Banerjee R. Raja, M. Narasimha, R. Shivakumar

In this paper, numerical simulation of magnetite, medium segregation and coal partitioning have been made in a 350 mm diameter cyclone. An attempt is made to assess the nature of impairment in efficiency in relation to the increasing amount of near gravity materials in coal. The CFD model approaches the Algebraic Mixture (ASM) model with the granular option and Reynolds stress model (RSM) to resolve the air core and turbulent mixing of the medium and coal particles. The partition characteristics of the DMC were modelled using both Lagrangian & Eulerian particle tracking for particles ranging in size from 0.5 to 8 mm and in density from 1200 to 2000 kg.m-3. Lagrangian frame work based Discrete Phase model used to simulate the coal particle trajectories inside the DMC and attempted to understand the residence time of different size and density coal particles. It was observed that coal particles having density near to separation-density (having fifty percent of probability to under flow and overflow) are exhibiting increased residence time than any density particles. As expected the smaller size coal particles shows higher residence time than the coarse coal particles. CFD simulations on effect of NGM mass fraction are simulated and analyzed using ASM model including for coal and magnetite. Coal particles with high NGM content show significant effect in misplacement of coal particles towards wrong products at all relative densities. The residence time of the particles increases because of its increased interaction with near dense particles. The effect of NGM fraction on overall cyclone performance as well as detailed flow assessment in terms of residence time distribution, NGM particle concentration profiles with respect to LZVV is presented.

Jan 1, 2018