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By V. K. Gupta

Several approaches to the estimation of the size discrete breakage rate and distribution parameters (kj and bi,j ) of the batch grinding kinetic model are available in the literature. Analysis of a large amount of data available in the literature and our own data on several pure minerals and complex ores has shown that it is not always possible to obtain correct estimates of the two sets of parameters using known approaches as several widely different combinations of k and b parameters can sometimes simulate the batch grinding data reasonably accurately. It has been found that there are two main reasons: (i) all size classes are not well represented in the data and (ii) functional forms used for estimation of the two sets of parameters are sometimes chosen somewhat arbitrarily (especially in the case of complex ores), though they are actually uniquely related through size continuous breakage rate and distribution functions. A suitable experimental methodology has been described and demonstrated using some synthetic data and actual experimental data. A mill function approach, which does not require making any assumptions about the functional forms for k and b parameters, is also described and demonstrated. This approach is promising, but requires further development.

Sep 1, 2012

By J. Y. P. Leite

In the Borborema Pegmatitic Province (Brazil) exploitations of several minerals are conducted by small producers. They use traditional techniques of gravity concentration in small-scale plants as jigs and vibratory tables. During decades the mining activity generated tailings with economic interest in particularly columbite-tantalite. Samples collected in tailing piles of a gravity plant were characterized in mineral composition, which shows in the heavy fraction the minerals spodumene, columbite-tantalite, ilmeno-hematite, garnet and cassiterite. The light fraction presents quartz, feldspar and muscovite. The degree of liberation of spodumene and columbite-tantalite were determined using optical microscopy that presents liberation in 100 µm (90% to columbite-tantalite and 100% to spodumene). Centrifugal concentrator Falcon SB-40 was used for concentration of these minerals and presents 65% recovery in mass to two stages with mass reduction about 85%.

Sep 1, 2012

By S. N. Shahcheraghi

Bioleaching method makes use of bacteria in solving metallic sulphides, so that these bacteria tend to convert insoluble metal sulphides into soluble sulphates. Since the kinetics description of this process is inevitable for better interpretation of relation between metabolism and growth of live organisms, as well as optimization of metals extraction processes, in this paper, this description is represented and designed in mathematic (kinetics) model for copper sulphide minerals based on Monod kinetics model. According to this model, special growth rate of bacteria (?) is a hyperbola function of restrictive substrate concentration (S). By Solving and developing of Monod kinetics model, a comprehensive kinetics model for bioleaching of copper sulphide minerals results. The designed is also applicable for other metal sulphides.

Sep 1, 2012

By K. Trybalski

Facing the optimization activities, which purpose is to minimize the copper processing costs, the main sources of their occurring were presented. In this purpose, the costs analysis was performed, divided to individual standings, for one of the polish copper beneficiation plants. It was proved, that the main component of the copper beneficiation costs is energy consumption, generated mainly in grinding and classification node, particularly by operating mills. The technological system ? grinding and classification node ? in KGHM Polska Miedz S.A., ZWR region Lubin was then selected to investigation. To evaluate the grinding and classification node, the energetic factors W were proposed, calculated on the basis of the energetic-technological data of process, given by node monitoring system. The correctness of the energetic factors selection to evaluate the work of this node and their practical application in industrial conditions was experimentally proved in other technological object. The selected technological object ? grinding and classification node ? was then mathematically modeled and optimized. The calculated energetic factors were the basis to build mathematical models, identifying industrial copper grinding and classification process. The models described correlation and character of dependency between factors and energetic-technical data of the process. These were regressive and neural networks models. On the basis of factors models, the optimization tasks were determined, which purpose was to select the optimal points of grinding and classification node work. Also, the estimated economical effect, possible to achieve after introduction of given monitoring values to grinding and classification node optimization system, was presented.

Jan 1, 2014

By Sepideh Javanshir

The process of liquid?liquid extraction of gold from chloride solution is complicated by the presence of many variables acting simultaneously in an unknown non-linear fashion for the determination of the final extraction efficiency. In practice, it is quite difficult to develop a model for predicting various properties of such process. Therefore, an alternative approach based on Artificial Neural Network (ANN) is considered to assist in the simulation process. Artificial neural networks (ANN) are powerful tools that can be used to model and investigate various highly complex and non-linear phenomena. This paper presents application of Multi-Layer Perceptions (MLP) to construct relationship that will be employed to develop a quantitative method for the estimation of the extraction efficiency as a function of hydrodynamical parameters such as stirrer speed, [AuCl4]- and DBC concentration, organic and aqueous flow rate. The model is shown to be in excellent agreement with the experimental data (R2 value for training and testing data was 0.9992 and 0.9915 respectively). Therefore, it can be used to optimize the parameters of liquid?liquid gold extraction with dibutyl carbitol (DBC).

Sep 1, 2012

By A. V. Kurkov

The secondary action reagents (SAR) are organic diphilic compounds capable of altering ac-id-base and donor-acceptor properties of the main collector and consequently the energy of collector interaction with the mineral?s surface, its hardness and fixation forms ratio through associates formation via the hydrogen bonds. When the basic flotation conditions are being established, convergence of the electronic structure of the collector and the mineral being extracted due to minerals surface preconditioning with modifiers and the most efficient collector choice. At the next stage of the selective flotation condition establishment SAR is selected for a more precise adjustment of the energy of the collector fixation on the mineral. Such an approach makes it possible to solve efficiently various issues of flotation separation of non-sulfide minerals. In particular neutral organic substances containing groupings C==O, S==O, P==O (ethers of carboxylic and phosphonic acids, amides of carboxylic, phosphonic and sulfonic acids) were proposed as SAR. In order to enhance the flotation process selectivity in the conditions of water recycling including the selectivity of carboxylic collectors especially in the environment of high hardness water flotation, it was proposed to use SAR with long hydrocarbonic radical and groups with enhanced electronic density within the molecule: N-methylolamides of alkylphosphoric acids and ethers of methylphosphonic acid. Introduction of small amounts of these compounds alongside with the main fatty-acid collector enhance the performance of fatty-acid flotation of fluorite, beryl, columbite etc., lowers the collector consumption, and completely compensates the depressive effect of recycled water. Di-2-ethylhexyl ether of methylphosphonic acid?CH3P(O)(OC8H17-i)2 (hexarane) was more thoroughly researched as such an agent within fatty-acid flotation process. Following aspects of the flotation system were studied: interaction of oleic acid and sodium oleate with hexarane in the liquid phase (infrared spectroscopy); heat emission under the interaction of hexarane-oleic acid ? sodium oleate ? calcium salts (isoperiboric diathermic colorimeter); colloid-disperse state of the collector influenced by hexarane (nephelometric analysis); dynamics of the mineral surface hydration due to the agents (method of indicator negative adsorption); hexarane effect upon the interaction of fat-ty-acid collector with calcium salts (complexometric method with Trilon-B); floatability of pure minerals (quartz, microcline, beryl, columbite) in Hallimond tube; hexarane effect upon oleic acid (sodium oleate) adsorption (nephelometric method for identification of the residual content of oleic acid and its forms within the solution). Upon the research it can be definitely concluded that the adjusting effect of such compounds as hexarane within the non-sulfide minerals flotation process is mainly determined by their interaction with the main collector both within the pulp and at the mineral surface with associates formation due to the hydrogen bond. The consequence is calcium oleates destruction with the release of the most active collector under flotation in hard water environment which determines the efficiency of hexarane joint application with fatty-acid collector under recycled water supply. Therefore the introduction of the class of secondary action reagents is supported by their operation mechanisms and flotation process function and determines a new approach to the development of efficient conditions of selective flotation separation of non-sulfide minerals.

Jan 1, 2014

By Ricardo Montero

At this time, over 300 tons of Au are used in electronic equipment each year with other precious and strategic metals such as Ag, Pt, Pd, Cu, Nb, Ta, etc. After the use-phase, the electronic devices become electronic waste (e-waste); consequently it is important to consider e-waste as a secondary supply for recovery of these metals. One of the most important components is the printed circuit boards (PCBs) because the amount of their precious metals is ten times higher than rich precious metals bearing ore. This paper presents the recovery of Au, Ag, Cu and Nb from PCBs of discarded computers using leaching column technique. The amount of these metals in used PCBs was: 613 g/ton of Au, 1515 g/ton of Ag, 36 g/ton of Nb and 23.4 % of Cu. The PCBs were crushed with a hammer mill until reaching a particle size between 3.33 mm to 0.43 mm. Then, it was leached with sodium cyanide solution in a glass column using the following conditions: sodium cyanide concentration 4 g/L, flux 20 L/kg PCBs day, pH between 10.5 to 11 and leaching time 15 days. Every day, after leaching, the pregnant solutions passed through a column with activated carbon to complete the closed loop system. The following recoveries were obtained: 46.6% of Au, 51.3% of Ag, 47.2% of Nb and 62.3 % of Cu. The products obtained are: a) loaded carbon that contains the desired metals and b) processed PCBs with precious metal contents. A preliminary technical-economic study shows the feasibility to create a small-scale PCBs recycling plant. The initial investment is on the order of US$ 155 639, considering the recovered metals from loaded carbon. The internal rate of return for 10 years period (IRR) and net present value (NPV) estimated are 27% and US$ 105 926 respectively. Keywords: printed circuit boards, recovery, precious metals, niobium, leaching column

Sep 1, 2012

By J. Wiese, K. Corin, Z. Song

"Relating flotation performance to the electrochemical characteristics of a pulp is complex both in fundamental research and in practice. In the case of thiol collectors, different Eh values in the flotation system can result in the formation of the dimer or the metal thiolate which may or may not enhance the hydrophobicity of the mineral. Reducing or oxidizing conditions in a flotation system, viz. changing the Eh value, are usually manipulated to achieve an optimum flotation response by control of pH and dissolved oxygen levels in the system. A variation in pulp potential may also be achieved by the addition of potential modifiers such as sodium hydrosulphide (NaHS), sodium hypochlorite (NaClO) or hydrogen peroxide (H2O2). There exists anecdotal evidence which suggests that the addition of small amounts of H2O2 to the flotation process can improve sulphide mineral recovery. The objective of the present study was to investigate the effect of the addition of the potential modifier, H2O2, on sulphide mineral recoveries and grades in the flotation of sulphide minerals from two copper bearing ores from China and compare the results to those obtained for a PGM bearing ore South Africa. Batch flotation tests were conducted using the three different ores at the natural pH of the different systems, in the presence of a xanthate collector and the absence and presence of H2O2 as a potential modifier. The results indicate that the addition of carefully controlled low concentrations of H2O2 resulted in improvements in flotation performance. INTRODUCTIONElectrochemical potential as a control parameter in the flotation of sulphide minerals has been widely studied (Allison et al., 1972; Gardner and Woods, 1979; Ross and Van Deventer, 1985; Chander, 2003; Woods, 2003; Javadi, 2013). There is concensus that in order to be recovered during flotation, sulphide minerals require a suitable redox environment. During the flotation process thiol collectors and sulphide minerals are involved in electrochemical reactions which result in the formation of hydrophobic species at the mineral surface (Finkelstein and Goold, 1972; Rand and Woods, 1984). Sulphide minerals act as semiconductors and electrons are transferred during the interaction of the mineral with collector. The resultant potential difference and its magnitude are responsible for the transfer of electrons and the rate of the reaction (Bard and Faulkner, 2001; Fuerstenau et al., 2007). Reducing or oxidizing conditions in a flotation system, viz. changing the Eh value, may be manipulated to achieve an optimum flotation response by control of pH and dissolved oxygen levels in the system (Heyes and Trahar, 1979). The use of potential modifiers viz. reducing or oxidizing agents which include H2O2, NaClO, and NaHS, is an alternative method by which to control the potential of the pulp in a flotation system which may or may not promote the flotation of desired minerals (Rao, 2004). The oxidizing agent, H2O2, undergoes a cathodic reaction which can result in the enhanced flotation of valuable minerals. The potential of the system is increased which results in a shift in the mixed potential of a mineral. The magnitude of the over-potential influences the rate of the oxidation process and thus the flotation response of sulphide minerals (Kocabag and Guler, 2008). Equation 1 shows the proposed oxidation of xanthate by H2O2 (Lipkina and Streltysn, 1970)."

Jan 1, 2018

By A. M. Ozbayoglu

Gross calorific value (GCV) of coals was estimated using artificial neural networks, linear and non-linear regression techniques. Proximate and ultimate analysis results were collected for 187 different coal samples. Different input data sets were compared, such as both proximate and ultimate analysis data, and only proximate analysis data and only ultimate analysis data. It was observed that the best results were obtained when both proximate analysis and ultimate analysis results were used for estimating the gross calorific value. When the performance of artificial neural networks and regression analysis techniques were compared, it was observed that both artificial neural networks and regression techniques were promisingly accurate in estimating gross calorific values. In general, most of the models estimated the gross calorific value within ±3% of the expected value.

Sep 1, 2012

By Mauricio Guimarães Bergerman

At the regrind or secondary grinding stages of base metal ores, the concern about energy efficiency is usually extremely important. In general, the specific energy consumption at this stage is higher than during the primary grinding stages. In addition, a tendency of finer grinding has been observed in the new projects of metallic minerals, due to the finer mineral liberation, which leads to increasing capital and operational costs. At Vale?s new copper projects in Brazil, regrind sizes with a P80 of approximately 40 to 20 µm have been necessary. Conventional ball mills, adequate for primary grinding, usually bring about low energy efficiency with products bellow 50 µm. Vale is using the vertical mill on its copper projects ? Sossego and Salobo, in order to optimize the regrind of rougher concentrates and reduce energy consumption. This paper presents the results of industrial surveys carried out on the Vertical mill circuits of Sossego plant during its initial years of operation, and compares these results with the design criteria and laboratory regrind tests used for the mill scale up. Keywords: grinding, regrinding, copper, vertical mill, stirred mill

Sep 1, 2012

In this paper, various methods, such as XPS, XRD, SEM and zeta potential measurement are applied to investigate the action mechanism of sodium sulfide in flotation of lead and zinc oxysalt minerals. The experimental results show that the mechanisms of sodium sulfide in flotation of lead oxysalt minerals and zinc oxysalt minerals are different: on the surface of cerusite, there is lead sulfide phase formed under the reaction of sodium sulfide, resulting that the cerusite surface shows the form of galena, which is advantageous to the adsorption of anion collector and improves the floatability of cerusite as a result. On the surface of zinc oxysalt minerals, there is no zinc sulfide phase formed, but the sodium sulfide increases its surface electronegativity, and enhances the adsorption of cation collector lauryl amine, so the floatability of zinc oxysalt minerals is improved. The difference of action mechanisms of sodium sulfide on lead and zinc oxysalt minerals exactly explains the reason why different collectors are selected in the flotation of cerusite and smithsonite, which are both carbonate minerals although.

Jan 1, 2014

By Kyoungkeun Yoo

A citric acid leaching test after heavy medium separation process was performed to remove the heavy metal contaminat such as Pb, Cu, and Zn from contaminated soil. The lead component was removed from soil by heavy medium separation whereas zinc component shows 0 % - 37.9 % removal ratio with particle size. The citric acid leaching was conducted to remove the remained zinc component. The removal ratio of Zn reached to more than 95 % under the conditions; 10 % in pulp density, 200 rpm in agitation speed, 50 °C, 2 mol/L in citric acid concentration at 2 hrs in leaching time. These results suggest that the heavy medium separation method followed by citric acid leaching is effective for treatment of soil contaminated with various chemical forms of heavy metal. Keywords: metal contaminated soil, citrate, heavy medium separation, zinc

Sep 1, 2012

By T. Damyanov

Spherical grinding media (balls) are the most widely used media for comminution of ores by grinding. A modelling simulation study of the behavior of two grinding media in the grinding process was conducted to determine the possible advantages of the new shape milling bodies called tetraballpebs. Tetraballpebs are in the shape of tetrahedrons with spherical convex walls. A three dimensional CAD model of the mill drum with a diameter of 1200 mm was used. A continuous operating mode was simulated in terms of the 3D contact elements of the model (milling bodies and mill drum). Simulation tests were carried out in a typical grinding mode and at a typical rotational speed of the drum mill (75 per cent of the critical speed in cataracting mode). Studies carried out with both grinding media include equal number of milling bodies with the same weight and volume. Having thus ensured a uniform mass of the grinding media and same number of milling bodies, and constant other conditions and process parameters, conclusions can be drawn about the influence of the shape of the milling bodies on the grinding process. A kinematic analysis of the system using CAE (computer-aided engineering) model parameterization was conducted. The controlled parameters are: ? Power draw; ? Kinetic energy of each milling body; ? Motion of milling bodies inside the drum Keywords: grinding, grinding simulation, balls, tetraballpebs, DEM, CAD-CAE

Sep 1, 2012

By Y. P. Lu

PET/kaolin nanocomposites were prepared with melt blending and the structure of the composites was characterized through IR techniques. The results showed that there is stable chemical bonding between PET and kaolin. In addition, the dispersion condition of nanokaolin was observed by means of SEM and TEM. As a result, the thickness of the dispersed nanokaolin particles in PET matrix is mainly from 20mm to 200nm, and the nanosized particles congregate to some extent in the samples. In addition, it was found the kaolin particles almost homogeneously dispersed in the PET matrix, without preferential orientation because of the shear effect due to melt blending. Furthermore, the mechanical properties of PET/kaolin nanocomposites are dependent on the modification efficiency of nanokaolin. With the poor efficiency, the nanokaolin particles tend to aggregate at a high content and have a bad interfacial compability between nanokaolin and PET matrix, which lead to stress concentration, so the mechanical property descends. Experiments of different contents of modified nanokalin indicated that the intensity of PET/kaolin nanocomposites decreased firstly, then increased, and then decreased, with the nanokaolin content of 4 to 5 percent, the rupture stress of the composites showed a maximum value, which was higher than that of pure PET. On one hand, nanokaolin decreases the function among PET macromolecules, which will decline the mechanical properties, on the other hand, the piece structure of kaolinite improves the intensity of the nanocomposite. When the nanokaolin content is low, the former has the dominant effect on mechanical property, while the latter will play a leading role with the content increasing. But if the nanokaolin content still increases, the agglomeration and stress concentration will be obvious.

Jan 1, 2014

By Duong Huu Hoang, Nathalie Kupka, Urs A. Peuker, Martin Rudolph

"The froth ability, froth stability and the froth structure are strong influences in flotation process i.e. on water recovery, bubble size, entrainment of gangue particle, flotation rate constants, grade and recovery. The labscale flotation of rich apatite ore with a high mass pull leads to significant changes in pulp and froth properties over time. The froth stability decreases with increasing the flotation time. These changes can be related to different solid contents, reagent concentration, froth heights and bubble size distributions. This study presents the results from froth studies and discussions on the particle size of fully liberated silicates and degree of entrainment based on automated mineralogy size-by-size analysis. The change of entrainment in a rich apatite ore batch flotation with time will describe more precisely by measuring froth properties using a Dynamic Foam Analyzer. It is concluded that the degree of entrainment is not only dependent on particle size but also the pulp density due to its effect on particle settling and also froth properties in varying resistance to particle drainage. Furthermore, entrainment models are applied to predict the effect of size, flotation time on entrainmentINTRODUCTIONFroth flotation belongs to the group of heterocoagulation separation techniques. Froth flotation is classically divided into two active zones, the pulp zone (where particle collection occurs) and the froth zone. A schematics drawing of the interaction between both zones is plotted in Figure 18 (Yianatos and Contreras, 2010). In froth flotation, the collision probability in the collection zone is governed by the physics of the process or hydrodynamics (Wills and Finch, 2016). The true flotation event in the pulp occurs when the hydrophobic valuable mineral particles collide with bubbles and formation of a stable particle-bubble aggregates moving upwards against gravity to the froth phase (Yianatos et al., 2009)."

Jan 1, 2018

By M. Taheri

Multiple Attribute Decision Making (MADM) method is applied to select tailings site of the Gol-e-Gohar Iron Ore Processing Plant in the Kerman province, south-eastern of Iran. To select tailings site, screening is applied on eight location proposed by Binnie and Granges. Consequently three sites identified for further studies. Evaluation factors include only the most important factors such as efficiency ratio, elevation and distance to processing facilities, occurrence of faults and fractures. Crisp values such as efficiency ratio, elevation and distance can be determined by measurements and calculations, but some factors such as occurrence of faults and fractures are presented as linguistic values that can be described with triangular fuzzy numbers. Based on evaluation values obtained an optimal tailings site can be selected using a modified Technique of ranking Preferences by Similarity to the Ideal Solution (TOPSIS) given crisp data and linguistic variables as the alternatives of attributes. Each attribute?s weight is assigned using the analytic hierarchy process. The final ranking order aids in the selection of tailings site. Finally, the stages of modified TOPSIS method were applied and site No.2 situated in 5400m to the mill was selected as the best alternative.

Jan 1, 2014

By M. Illikainen

Limestone is used for neutralization of acid leachates in a number of hydrometallurgical processes. The aim of this study was to clarify how limestone ground to different particle sizes can neutralize sulfuric acid. The laboratory scale ball mill was used in grinding experiments carried out using ball sizes of 20, 30 and 40 mm and volumetric slurry densities of 30, 40 and 50 percents. Varied grinding times were used in order to produce limestone samples with different particle size classes on which the neutralization potential and rate were determined. The results of the study showed that the neutralization potential of limestone is not dependent on its particle size between 5 and 120 µm. However, the particle size strongly affected the neutralization rate of sulfuric acid: The smaller the particle size, the higher the rate of neutralization. Thus, when optimizing the cost efficiency of the process, the optimal degree of grinding should be considered taking in account the required residence time in neutralization phase.

Sep 1, 2012

By L. Weitkämper

The big challenge at present and in the future is the economization of resources. This is applied for the whole industry but particularly in fields of mineral processing. The most important resources are energy and water. The shortage and price advance of energy is worldwide noticeable whereas the shortage of water is regionally limited at present. However due to the increasing world population, associated with a rising standard of living, water will become more and more important. Studies of the Unesco from 2001 indicate that the total water consumption raised seven times since the last 100 years at a growth of population of just three times. (UNESCO-Currier, 10/2001). This trend is going to be increased. While today more than 90 % of the humanity has access to clean water, in 2050 just about 50 % will be in the same situation. These figures indicate the importance of a gentle handling with the resource water. Further more the disposal of fine products, containing most of the water, is an environmental concern and in the future the mining and processing of raw materials will become important and necessary in desert, arid or permafrost areas. In these areas just efficient dry cleaning technologies will allow an economical beneficiation or better enable the processing at all. Most of the separation technologies with high throughput rates in mineral processing are based on wet processes. This applies especially for the separation of fines. Though there are some dry technologies available for the separation of coarse materials, like pneumatic gravity separation [air jigs and air tables], magnetic separation and not least sensor based sorters. Dry separation of fines is bounded mostly on cost intensive and low throughput technologies. The pneumatic separation undergoes at present a renaissance, mainly due to the development of the all air jig by the German supplier Allmineral. This newly developed sorting device yields good results in the separation of coarse to medium size material. All these facts and figures show the potential and motivation for developing an efficient dry separation device for fines. The following article delineates the development, performance and chance of a new dry separation technology for fines.

Jan 1, 2014

By Zhong Hong

A novel ilmenite collector, tert-butyl benzoic hydroxamic acid (TBHA), was investigated in this paper. The flotation performance and adsorption mechanism of TBHA to ilmenite were evaluated through pure mineral flotation tests, ?-potential measurement and IR spectrum analysis. The experiment results indicated that TBHA exhibited strong collecting capability to ilmenite under pH 6.0-8.5. At pH 7.0-10.0, TBHA existed in the form of anionic species in aqueous solution, and the ?-potential measurement results showed the surface of ilmenite maintained negative and more negative after the adsorption TBHA on it, which inferred that TBHA might adsorb on the surface of ilmenite through chemical interaction. The IR spectrum analysis further confirmed the chemical interaction between TBHA and ilmenite surface. Keywords: Tert-butyl benzoic hydroxamic acid, Ilmenite, Flotation, Chemical adsorption mechanism

Sep 1, 2012

By M. D. Vilarinho, W. Xuan, F. Vasconcelos Guimarães

"This article summarises the efforts to reduce the energy consumption in grinding in a magnetite ore beneficiation plant. ArcelorMittal Kryvyi Rih ore beneficiation plant produces magnetite concentrate at 65% Fe and 8% SiO2, of which the D80 is approximately 44µm after three stages of grinding with ball mills and magnetic separation. Characterisation and laboratory scale bench tests performed on samples from the beneficiation plant indicate that the industrial flowsheet could be simplified. After the first stage of grinding and magnetic separation, a significant size fraction of the intermediate concentrate is already well liberated. Therefore, it can be directly concentrated in a second stage magnetic separation without further grinding. If a screen of 150µm size can be implemented after the first stage of grinding-magnetic separation, only the oversize of screening, representing 35% of the material, requires secondary and tertiary grinding and magnetic separation. The combined concentrate from the two fractions already meets the industrial specifications. This new route can provide the same final product, with fewer mills; it saves around 30% in energy consumption only in the grinding step without changing the main structures of the processing plant.INTRODUCTION Comminution, including crushing and grinding, is responsible for at least 40% of total energy usage in mining and mineral processing. This paper shows an example to reduce grinding cost, by changing the flow sheet design strategy in ArcelorMittal Kryvyi Rih (AMKR).AMKR is one of the most important mining and steel complexes in Krivoy Rog basin in Ukraine, which has been studied over 100 years because of mining of iron ores. The iron ores are associated to Banded Iron Formation of the Saksagan suite, with an average iron grade of around 36 percent Fe. The total thickness of the Krivoy Rog Supergroup reaches 5-6 km, whereas that of the iron-ore Saksagan Group comprises up to 1400 m. High-grade iron ore extends to more than 2,000 m below present surface"

Jan 1, 2018