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By Luo Chuansheng, Rao Jinshan, He Xiaojuan, Qiu Xianyang

The dissemination grain size of chalcopyrite is really fine and refractory grains of -10µm take up 25%. Dissemination relationships among chalcopyrite with pyrrhotite, pyrite, marcasite and gangue minerals are complex. Content of Fe-bearing sulphides and Fe-bearing silicates associated with chalcopyrite reaches to about 60%. It’s hard to liberate and separate chalcopyrite from pyrrhotite. The above four are the main mineral processing difficulties of a copper ore in China. Because of the similar floatability and poor separation effect between chalcopyrite and pyrrhotite, enhanced depressing and collecting method was adopted in Cu-S separation before 2009. Due to the different magnetism among chalcopyrite, pyrrhotite and Fe-bearing silicates, magnetic separation is creatively induced in Cu floatation circuit based on the in-depth study of process mineralogy. High efficiency and new Cu-S separation technology of "Rough concentrate regrinding-pyrrhotite rejecting from middling by magnetic separation" and a highly selective copper minerals collector YL-1 had been developed to solve the difficult problems of refractory Cu-S separation, which are heavy load of middling recirculation,difficulty in upgrading Cu concentrate, unstable locked cycle and low separation indexes. And grade of Cu concentrate has been increased by 3.33%, recovery of Cu and Ag has been increased by 19.32% and 10% respectively.

Jan 1, 2014

By E. T. Tuzcu

In this manuscript, a new approach for modeling the rate of grinding process is explained. A review about grinding rate definitions so far is given and the possible ultimate way for grinding modeling is given as modeling the rate based on energy spectra. The traditional/phenomenological approaches for modeling size distribution of grinding mills give their place to a new generation modeling technique. Developments in the computational methods and necessity to model product size distribution of large mills, larger than ball mill size, paved the way for this novel technique. The traditional grinding rate models are mostly based on the back calculated breakage parameters from the experimental data. However, direct modeling of breakage parameters and hence the prediction of size distribution of the grinding mills may become possible with this approach. The material breakage data and discrete element method (DEM) energy spectra are the main components of this approach. Albeit the focus in this study is on modeling of breakage rate under impact mode of breakage, the abrasion mode of breakage was also tested by carrying out abrasion tests. Impact mode of breakage was analyzed using ultra-fast load cell device (UFLC) and drop weight tester. Dry tumbling test was carried out for abrasion experiments. Obtained material breakage versus energy data are combined with the collision energy spectra to obtain the breakage rate function. In addition, the material breakage versus energy information from the tests is converted into breakage distribution function. The model was verified in a lab scale mill (90 cm diameter-15 cm length). 10 to 15 kg of limestone was ground using 50 mm steel ball at varying conditions, i.e., rpm, volume loading. It is shown that the proposed model predicts all (1, 2, 4 min.) grinding intervals for all experiments highly accurate.

Sep 1, 2012

By B. Tora

The new method of evaluation of grindability of hard coal and its blend is shown. Standard Hardgrove test is used as a base to work out this method. The essence of this method consists of simulation of milling process in close circuit (mill-classifier) and determination of energy consumption and quantity of product under the constant feed flow. The research equipment designed specially for this project is described New method of grindability measuring completes standard Hardgrove method withdrawing its faults: ? bigger (c.a. 10 times) and more representative sample is used; ? the milling process is carried out in close circuit (similarly to the industrial condition); ? energy consumption of the milling process is determined for three samples, which differs in grain size. The new method of evaluation of grindability of hard coal and its blend is shown. Standard Hardgrove test is used as a base to work out this method. This method allows us to determine energy consumption of the milling process. The essence of this method consist of simulation of milling process in close circuit (mill-classifier) and determination of energy consumption and quantity of product under the constant feed flow. Our results will complete the Hardgrove method and will help us to better characterise coal. At the same time investigations in industrial scale are carried out. These investigations will verify this new method. Also a new mathematical model of the milling process is being elaborated. It will be used to predict behaviour of coals in industrial conditions.

Jan 1, 2014

By A. K. Majumder

In an effort to test the extent to which fundamental fluid mechanics can provide a prediction of particle separation, a study on a simple parallel-sided sluice has been carried out using glass bead and ilmenite mixtures at various particle concentrations and flow rates. Great care was taken to devise a flow splitter at the end of the sluice that permitted accurate measurement of the fluid flow profile and collection of slurry samples, allowing evaluation of the particle species concentration profiles. The actual particle separation taking place was compared to predictions made by first describing the fluid flow by a modified ?law of the wall? model. The hydrostatic pressure variation in the flow was taken into account and the eddy viscosity was calculated from a mixing length expression incorporating Van Driest?s damping function. Using an average density and viscosity provides an explicit expression for the velocity gradient that can be numerically integrated for the flow profile. The particle concentration distributions were then modelled with Hunt?s sediment transport model assuming the particle eddy diffusion coefficient to be the same as that for the water. Hindered settling velocities of the particles were calculated using Brauer and Thiele?s formula, which takes the particle size and density distributions and solids volumetric concentration into account. The resulting predictions of particle separation are shown to be a strong function of the settling velocities of the particles used. Keywords: flowing film concentrators, fluid velocity

Sep 1, 2012

By E. Scheepers

The process under investigation is the large-scale production of phosphorus. Gravity delivers the feed, consisting of pelletised apatite, coke and silica (in the form of gravel), to a submerged arc furnace through ten, evenly distributed feed chutes ensuring constant packed bed volume. Within this packed bed, solid-gas reactions are dominant in generating the gaseous product. These reactions, as well as the packed bed itself, were the main focus in the development of a fully three-dimensional CFD model in which fluid flow and energy distribution are represented as functions of chemical reactions, heating and melting of material and heat losses. The associated complex process interactions necessitated the creation of two process-specific, user-developed models that integrates accurate, thermodynamical data with computational fluid dynamics calculations, as well as reaction kinetics. The boundary conditions are provided by industrial measurements, and the key model parameters of reaction kinetics were obtained by laboratory experiments for different feed mixtures. Thirteen temperature probes installed inside the refractory lining of the furnace especially for this project allowed parameter fitting and validation to be guided within the constraints of real measurements. Simulation results reveal a thin, dome-shaped, reductive zone where conditions are optimum for maximum phosphorus recovery, as well as evidence of a thermal reserve zone similar to an ironmaking blast furnace located above this reduction zone. When compared to actual operating data, the CFD model can successfully predict the specific power consumption, the phosphorus in the slag and gaseous product flowrate under given operating conditions. This CFD model forms part of a larger project that aims to create a Dynamic-CFD hybrid control model.

Jan 1, 2014

By F. Xie

Low gold and silver leaching kinetics has been commonly observed in traditional gold-silver cyanidation process, especially in those heap-leaching operations. The reactivity and availability of oxidant was believed to be the critical limitation for gold and silver dissolution. The occurrence of silver sulfide such as acanthite (Ag2S) in the ore may also result in low overall silver extraction. Leaching of gold and silver sulfide in the ferricyanide-cyanide solution has been investigated through rotating disc tests and the assistant effect of ferricyanide on increasing the dissolution rate of gold and silver was noticed. The potential use of ferricyanide as an auxiliary oxidant in gold/silver cyanidation process was proposed based on the results of leaching of gold-silver ores.

Jan 1, 2014

By Y. Posedko Eugene, S. S. Gudkov, Yu. E. Emelyanov, A. V. Bogorodsky, A. V. Boldyrev, S. V. Balikov

"The article presents the results of precious metals leaching using halogen solvents and their precipitation on a sorbent in the process of pressure oxidation. A technology of pressure oxidation – carbon-in-leach treatment (POX-CIL) of refractory sulphide gold-bearing flotation concentrates with the addition of a halogen solvent and a sorbent was developed based on the laboratory studies and pilot plant tests. The technology involves the following steps: oxidation of a flotation concentrate; precious metals dissolution and recovery on a sorbent; precious metals elution; electrolysis of eluates; smelting of cathode precipitates with producing Dore beads. This approach ensures oxidation at least 98% of sulphides and gold of more than 95%. The POX-CIL process have the following patents: a patent of the Eurasian Patent Organization No.017438 “A method of processing materials containing precious metals and sulphides” and a patent of the Russian Federation No.2625146 “A method of precious metals recovery from refractory sulphide gold-bearing materials”.INTRODUCTION Gold-bearing ores are classified as readily amenable to cyanidation, or non-refractory, and not readily amenable to cyanidation, or refractory [1]. Special attention should be given to the three most common technological types of gold-bearing ore materials, according to the Irgiredmet’s classification: pyrite-arsenopyrite ores with finely disseminated gold locked in sulphides (physical depression of gold in cyanidation process); cupriferous gold-bearing ores, when cyanidation comes along with chemical depression of gold by mineral compounds (cyanisides); carbonaceous ores showing higher sorption activity to precious metals dissolved in cyanide. Direct cyanidation of refractory sulphide gold-bearing materials does not provide high recovery of precious metals. There are the following methods of refractory gold-bearing ores and concentrates preparation to subsequent gold recovery: roasting, fine grinding, bacterial and pressure oxidation (POX) [2]. Existing POX-cyanidation flowsheets involve high costs due to a large amount of process operations and using expensive and environmentally hazardous sodium cyanide."

Jan 1, 2018

By R. Singh

The present paper deals with the development of flotation based process for enrichment of a lead-zinc sulphide ore from Ganesh-Himal region of Nepal. Detailed characterisation and flotation studies were carried out under varying process conditions. The sample assayed 2.47% Pb with 13.6% Zn. The ore was predominantly made up of spahlerite and pyrite in association with subordinate amounts of galena, minor amounts of pyrrhotite and chalcopyrite. Dolomite was the main gangue. The modal analysis showed the probability of fair liberation of sulphides from gangues around 210 microns but the locking of galena with sphalerite and other sulphides continued to finer sizes. Under the optimum process conditions the rougher lead and zinc recoveries were 96.3% and 90% respectively. Multistage cleanings of rougher products proved helpful in improving the concentrate grade, meeting the required specification. Based on the studies undertake a process flow-sheet for the concentration of the ore to individual lead and zinc concentrates was developed.

Jan 1, 2014

By N. N. Orekhova, I. V. Shadrunova, N. G. Novikova, N. ?. Volkova

The purpose of the research is scientific substantiation and formulation of strategy and technical solutions of handling liquid wastes of plants producing and refining copper-zink pyritic ores. In the course of research studied are chemical composition of technogenic waters of mining plants as well as water and alluvia of intake river within and outside a sanitary zone of Southern Ural mining plant using inductively coupled plasma mass-spectrometry and X-ray fluorescence analysis techniques. A particular focus is made on microcomponent composition. Novel data on Cd, Li, Be, Mn, Co, Cu, Zn migration with technogenic flows and accumulation of these elements in alluvia is obtained. It is showed that extraction of valuable components from technogenic waters is a novel problem for refiners that can be solved only in cooperation with mining industry ecologists. Laboratory research of selective copper and zink extraction into corresponding practical products by galvanocoagulation and sulphide precipitation is carried out. Common factors of phase formation are studied using physicochemical modeling, X-ray phase analysis and electronic microscopy. Methods of intensification of processes and increasing of extraction ratio of metals in products are elaborated. A technology of comprehensive processing of undersoil waters is proposed. Enlarged laboratory and pilot plant tests of technological solutions for protecting hydrosphere and extracting metals from mine waters carried out on several plants of UMMC-Holding Corporation showed a possibility of obtaining additional products having weight content of metal which is profitable for consequent metallurgical processing and purification of waters to comply with quality standards. A possibility of transformation of technological chain depending on season variability of water quality is put behind the designed technological schemes.

Jan 1, 2018

By J. E. Gebhardt, D. McBride, T. N. Croft, M. Cross

"Heap leaching is well-established as a relatively low-cost and low-energy method of extracting metals from low grade ores. However, the design methodology, attention to the engineering details during heap construction and the long time scale in metal recovery makes the process susceptible to significant variation in the success of a heap leach operation. Often the laboratory predicted recovery rates are not achieved on site due to poor understanding of the complex physics of flow and coupled solid-liquid-thermal reactions within the multi-dimensional heterogeneous ore body. Given the large scale of commercial operations, small changes in metal recovery can substantially change the operating profitability. While there are a variety of approaches to heap leach modeling, computational fluid dynamics (CFD) modeling coupled with leach kinetic models offers a methodology to describe and understand the complexities of heap leaching. The CFD model uses leach kinetics specific for the mineralogy of the ore, including gangue chemistry, and provides an energy balance to calculate and predict temperature. Coupled with the CFD model’s inherent capability for modeling complex fluid flow, the physics and the chemistry of the heap can be simulated. This provides a tool for engineering design, as well as forecasting heap production under different scenarios. The calibrated model is used to simulate a three-dimensional test heap under fluctuating meteorological data, such as precipitation events, periodic solution application, and notably temperature. These simulations provide support for a methodology to design and engineer heap leaching of low grade copper sulfide ore. INTRODUCTION Worldwide copper ore reserves are faced with decreasing head grades with copper sulfides, particularly chalcopyrite being the predominant mineralogy (Nesse, 2000). Heap leaching offers an economical way to recover copper from low grade ore. The ore is stacked and a leach solution is applied and allowed to trickle though the porous bed of ore to extract target metals. The heap can be built with run of mine material or crushed ore and is constructed in order to achieve percolation of the leach solution to all regions. Bartlett (1998) provides an authoritative overview of the solution mining process where the leach solution interacts with the solid, the lixiviant dissolves the target minerals from the solid into the solution, and the dissolved species are transported out of the heap for subsequent recovery. Petersen (2016) provides a recent review of heap leach technology and emerging and potential future applications, and Ghorbani et al. (2016) summarizes the current state and challenges of the technology. Early applications of heap leaching offered a low cost technique to achieve high recoveries from oxide ores, typically greater than 70% depending upon the kinetics of reaction. As world copper resources transition to mainly copper sulfide mineralogy, such as chalcopyrite based ores, achieving high recovery from these copper sulfide deposits is proving more difficult due to the complexity of the leach kinetics, which leads to low leaching efficiency."

Jan 1, 2018

By Fengming Li, Baocheng Song, Yuemin Zhao, Hailin Dong, Liping Peng, Chusheng Liu, Chenlong Duan

The large-scale vibrating screens with high processing capacity and efficiency are now in great demand in the mineral processing industry of China. However, as the equipment is always suffering from the strong external harmonic exciting force, the inertial force and the impact from the minerals, the fracture of the beam and the crack of the lateral plate are easy to occur, which has a negative effect on the reliability of the equipment itself and the industrial production. Considering the essential high reliability of the equipment, a new large-scale vibrating screen with duplex statically indeterminate mesh beam structure (VSDSIMBS) was developed. The natural characteristics, namely, the natural frequency (or the modal frequencies) and the natural mode, and the dynamic characteristics of the VSDSIMBS were obtained by the modal analysis and the harmonic response analysis. In addition, the dimensions and the constructions of the statically indeterminate plate and the mesh beam were chosen as the design parameters, to which the sensitivity of the whole mass, the maximum deformation and the maximum stress of the duplex statically indeterminate mesh beam structure (DSIMBS) were summarized for the optimization of the DSIMBS. Now the large-scale VSDSIMBS is being well used in China.

Jan 1, 2014

By R. Mukherjee

Consistency of Run-Off-Mine (ROM) quality plays an important role in mineral processing which is not very often talked about. The major impediment is limitation of sampling ROM ore, which makes processing plants to run without any realtime feedback on ore quality that comes in. The process of direct determination of Run-Off-Mine (ROM) ore quality is expensive and time consuming as drawing and preparing representative samples from blasted muckpiles are constrained by large sample size and inherent heterogeneity in terms of size and chemistry. In absence of techniques for direct measurement of quality, monitoring and control of ROM, feed to the processing plant at Joda East Mine, like all other iron ore beneficiation plants worldwide, is largely based on blasthole sampling and subsequent chemical analyses of blastcone chips. While such indirect methods proves to be more accurate for representing whole of a mining block or blasted muckpile (~30-50KT/blast), it is indeed a challenge to ascertain and predict day to day input quality for a part there off. This eventually leads to a gap between predicted and actual ROM quality, resulting in difficulties in process control, in turn, and leading to wide swings in product quality. Hence, it is imperative to bridge the gap between predicted and actual ROM quality by arriving at means, which ensure consistent plant feed grade to deliver consistent output. The paper discusses an efficient and affordable alternative for effective prediction of ROM alumina which has been developed by integrating blasthole quality database in GPS based Truck Dispatch System (GPS-TDS) at Joda East Mine. Initially, GPS-TDS has been installed for optimizing production parameters only, but this development has helped in further utilization of GPS-TDS for real time quality monitoring by improving ROM grade prediction and scheduling from several ore blocks in active mining areas. Keywords:run-off-mine (ROM), blast hole, feed grade, GPS-TDS

Sep 1, 2012

By John Nell, Paul den Hoed

Carbochlorination tests were conducted with matched particle-size fractions of rutile, ilmenite and high-titania slag in a small bubbling fluidized-bed reactor. The effects of temperature, the type and proportion of solid reductant in the charge, and the fraction of Cl2 in the fluidizing gas were investigated. Tests confirm the need for solid carbon in the bed if chlorination is to run at high rates. With solid carbon in the bed, CO supplied with the fluidizing gas does not increase significantly the degree of chlorination after 75 minutes. Ilmenite is chlorinated more quickly than titania slag, which in turn is chlorinated more quickly than rutile. Rates of chlorination at 1100°C and 1000°C are much the same and significantly higher than at 900°C. Chlorination is associated with significant increases in particle porosity (even for rutile), which is brought about by the rapid initial chlorination of FeO and MnO (in ilmenite and slag) and (it is argued) by the chlorination of Ti2O3 which forms at high-energy surface sites. A reaction mechanism is presented; where possible, its validity is demonstrated by the support of empirical observations.

Jan 1, 2003

By S. Serranti

The recycling of end-of-life concrete into new concrete is one of the most interesting options for reducing worldwide natural resources use and emissions associated with the building materials sector. The possibility to realize a larger re-use of silica aggregates from old concrete, strongly contributes to reduce environmental impact (reduced exploitation of natural resources, reduction of CO2 emissions, airborne dust production, etc.).To reach this goal, innovative processing techniques, as well as innovative sensing units and architectures have to be developed. In this perspective an analytical approach, based on hyperspectral sensing techniques, is proposed, discussed and critically evaluated in order to perform an automatic quality control assessment, finalized to maintain a high standard of concrete demolition waste, from the earliest stage of recycling to the further processing stages, according to the detected in-situ demolition waste characteristics. The paper deals with the analysis and the evaluation of the problems related to the integration of this approach with state-of-the-art demolition and building processes and procedures. Keywords: end-of-life concrete, recycling, hyperspectral imaging, NIR spectroscopy, quality control

Sep 1, 2012

By V. V. Morozov, Ganbaatar Zorigt, Delgerbat Lodoy, Y. P. Morozov

"At the processing plant Erdenet, a new facility for advanced ore diagnostics in-stream (at the conveyor), based on optical analyser of mineral composition, was tested. Such systems provide highly accurate in-stream measurements of ore properties. The system provided information on the ore mineralogical composition, the particle size distribution and the impregnation of minerals. A special flatbed facility for optical spectrum-based estimation of fine-crushed ore has been developed, being incorporated into the existing system of ore sampling and analysis. Application of the flatbed facility renders possible a high accuracy of determining ore mineralogical composition. High precision of the optical spectrum-based estimation is achieved using special devices, installed in the sampling and the sample analysis flow sheet, applied by the technical control department. Modern systems for optical spectrum-based estimation of ore grade provide a basis for effective automated control of ore benefication processes, based on the principle of advanced ore grade control. Process management task of grinding and flotation was to choose options that take into account the composition and grade of the ore coming. The calculation data array comprises consumption of reagents, ore processing, grind size etc. The systems implemented at the processing plant contributed to increasing copper and molybdenum recovery. INTRODUCTION In-stream ore grade analysis is a new trend in effective control of ore benefication processes. This is realised based on radiometric measurements in the X-ray and visible spectrum regions, in which mineral components of the initial ore (Sbárbaro and Villar, 2010) or the benefication products become apparent (Hyotyniemi and Ylinen, 1998; Haavisto and Hyötyniemi, 2010). An important advantage of such methods is in-stream measuring ore parameters, including mass fractions of individual minerals, which makes it possible to use the information obtained in the processes of automated control."

Jan 1, 2018

By Arkady Senchenko, Andrey Vasiliev, Alexander Aksenov, Metodi Zlatev

"This paper considers the issue of treating argillaceous oxidized ores with low gold grade (around 1.0 g/t). These ores according to their gold recovery level can be treated by heap leaching and agitation cyanide leaching, but low gold grade makes this treatment uneconomic. Heap leaching of argillaceous ores requires high consumption of binding agent for pelletizing to create suitable hydro-physical properties of material, which leads to increasing process cost and makes the material treatment unprofitable. Agitation cyanide leaching of this ore requires grinding processes; these expenses would not be paid back by the amount of gold recovered. Considering the above, poor argillaceous oxidized ores are recommended to be treated according to a combined technology including fractionation of ore, heap leaching of coarse fraction and agitation leaching of argillaceous fraction. Complex approach application allows one to avoid expenses incurred for material grinding and high consumption of binding agent for pelletizing. The success of this technology implementation will firstly depend on the quality of material fractionation, therefore the section of disintegration and division of ore into different components will be the most important part of flowsheet development for gold production. When disintegrating minerals at positive temperatures both standard (mechanical disintegration - scrubbers) and innovative (hydraulic method of disintegration - HydroClean units) equipment is applicable. HydroClean units are characterized by lower energy and water consumption. In a number of cases it is required to treat frozen ores. When treating frozen material standard approaches to disintegration are not reasonable due to their low efficiency. In order to treat frozen material a two stage disintegration flowsheet with screening after each stage is recommended. The first stage is recommended to be performed in a scrubber, the second - in a HydroClean unit. This technological flowsheet will provide high and steady values for ore separation into fractions at low energy consumption for disintegration."

Jan 1, 2014

By Ritva Tuunila, Antti Häkkinen

"Wet stirred milling is one of the most effective grinding methods in producing very fine powders in large scale production, but it is a very energy-intensive process, especially when pigments or even nanosize particles are produced. Therefore, optimization of the process parameters is important. The specific energy consumption is a function of stress energy, which describes the effect of tip speed and media characteristics on grinding, and is related to the number of stress events during milling. In effective grinding, a large number of stress events are necessary. The stirrer configuration influences the number of stress events and their intensity, because the motion of the media and the suspension are caused by a rotating stirrer. The effect of three different stirrer types: a pin, disc and blade stirrer, on the grinding rate, i.e. product fineness and specific energy were investigated in this study with a batch laboratory stirred mill with two tip speeds. The material used in the experiments was calcium carbonate. The results obtained with the smaller tip speed showed approximately similar grinding rates and energy consumption for all stirrer types. When looking in closer detail, the blade stirrer seemed to give the finest product with all grinding times compared to the pin and disc stirrers, which both produced almost the same product fineness with the same grinding times. The specific energy consumption was the smallest with the disc stirrer, but not very big differences were obtained. With a higher tip speed, greater differences occurred both in grinding rates and specific energy consumption. The blade stirrer was the most effective in grinding, and the pin stirrer the next. The net energy consumption for the blade and pin stirrers was almost the same, but it was slightly higher for the disc stirrer."

Jan 1, 2014

By A. N. Zagorodnyaya, Ye. G. Bochevskaya, E. A. Sargelova, Z. S. Abisheva, A. S. Sharipova

"In Kazakhstan, there is a unique sulphide copper deposit, in the ores containing the natural isotope of osmium-187 (more than 90 %). In the pyrometallurgical processing of concentrates for the target metal, osmium is mainly sublimated, with wet cleaning of metallurgical gases (dust and gas mixture) 40 % of it together with rhenium passes into washing solutions (wash acid). On the basis of this acid, the production of ammonium perrhenate was organized at the enterprise of the RSE ""Zhezkazganredmet"" and for the first time in the world practice - the isotope of osmium-187. However, the degree of its recovery from solutions does not exceed 8 % of the amount supplied with the charge or 25 % of the amount that was received for extraction. But the bulk of it (~ 75 %) remains in the raffinate, discharged to sewage treatment plants (wastewater). The studies presented in this work are aimed at solving the problem of osmium isotope-187 extracting from wastewater, which are a potential source of increasing metal production in Kazakhstan. The aim of this work is the development and scientific justification of osmium deposition regimes from wastewater using such reagents as thiosulfate and sodium sulphide. The influence of various physicochemical factors on the precipitation of the osmium was studied and optimal conditions for its maximum transition to sediment were chosen. An original method for obtaining osmium concentrate in the presence of sodium thiosulfate with the addition of potassium iodide from a new type of wastewater - man-made ammonia solutions has been developed. These solutions were combined mother liquors of solid-phase stripping operations and dissolution of pulp of crude ammonium perrhenate. On the basis of the obtained results, a settling technology for extraction of the osmium from man-made ammonia rhenium-containing solutions was introduced at RSE ""Zhezkazganredmet"". It should be noted that the degree of extraction of osmium, depending on its concentration in solutions entering on the settlement, and taking into account the addition of sulfuric acid, will vary from 60 to 90 %. The recovery of osmium during the test period was 58 %."

Jan 1, 2018

By Dmitriy Kim, Natalya Ibragimova, Galina Sedelnikova

Gold and copper are lost in flotation tailings in mineral processing of copper-zinc-pyrite ores. Large resources of precious and base metals have accumulated in tailing ponds of Russian plants. Object of the study is the sample obtained from Ural Mining and Metallurgical Company in Russia. The main constituents in flotation tailings are Au, Ag, Cu and Zn with content 1.4 g/t, 12 g/t, 0.66 and 0.5% respectively. The flotation tailings are a refractory material. Gold, as main metal, is fine encapsulated in sulfides, mainly in pyrite. Gold extraction from tailings is 34.0 and 42.7% at P42 and P90 of 0.074mm particle size respectively. In this work heap bioleaching of tailings was studied for oxidation sulfides (pyrite and chalcopyrite) with using mesofilic and moderately termofilic bacteria in acidic solutions. The tailings had low filtration property (< 0.3 m/day) and pelletization was used before bioleaching. Copper containing converter slags flotation tailings and calcium oxide were used as binding material for increasing filtration property of tailings. Copper was extracted in sulfate solution and was precipitated by cementation after cleaning of bacterial solution from iron. Copper recovery was 56.8% at content 61.4% in precipitate. The biooxidation of pyrite was 80%. Cyanidation, leaching with thiourea and heap leaching by cyanide were tested too. Gold extraction from solid bioresidues was 82, 75.3 and 77% respectively. The results of this investigation were recommended for pilot test.

Jan 1, 2014

By N. Vasumathi

Most of the Iron ore washing plants set up in India in the earlier days consist of sizing of the ore by dry / wet screening, washing and classification by screw classifiers. In this classical approach, iron values were lost in the form of fines and ultrafine into the tailing ponds as they had little commercial value in those days and accumulated in huge quantities over the years. As the high grade deposits are getting exhausted and the demand for high grade finer material for pellet making is ever increasing, focus is shifting towards recovering the values from the erstwhile tailing ponds by column flotation. This is also supposed to mitigate to a certain extent the environmental problems caused by the ever expanding and unmanageable tailing dams. A case study is presented wherein a composite sample is prepared from samples drawn systematically from multi - locations in a sprawling tailing dam. Laboratory scale column flotation tests on this composite tailings sample, basically originating from two operating iron ore beneficiation plants of JSW Steel Ltd., one of the leading producers of steel in India are found to be encouraging. Desliming followed by reverse and cationic flotation tests using flotation column resulted in the concentrate of 61.88% Fe, 4.81% SiO2, 2.52% Al2O3 and 3.30% loss on ignition (LOI) from the tailings analyzing 57.86% Fe, 7.10% SiO2, 3.52% Al2O3 and 6.14% LOI with 52% weight recovery. The causes for the quality improvement could be attributed to desliming of un-liberated ultra fines of kaoline and hydrated iron oxides and their further reduction by efficient flotation process. The process and the cationic collector developed for this purpose are adopted in the new flotation plant created to treat these tailings. Keywords: iron ore, washing, ultra fines, tailings pond, column flotation

Sep 1, 2012