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Nowadays, the more successful plants are those who have adopted effective and efficient strategies to optimise their plant operation. As the ?heart of the plant? could be viewed as the mil-ling/grinding area, one of the key steps in plant optimisation is, therefore, ensuring the mill is operating properly. In the past, when primary, secondary and tertiary crushers fed material directly to large ball mills, the energy efficiency of the concentrator was determined for the most part by the ball mill operation, whereas now the energy efficiency of a plant often rests largely on the semiau-togenous grinding (SAG) mill operation. As a result, mines have shifted their emphasis in optimization from ball mills to SAG mills. The grinding mill?s energy efficiency essentially depends on ore characteristics and the discharge rate of broken particles, which in turn depends on how efficiently the discharge pump (grate and pulp lifters) operates. The essential function of pulp lifter being to transport the broken material and slurry out of the mill, its design optimization therefore affects the discharge capacity (or mill throughput) of AG and SAG grinding mills. This paper will discuss how the optimised design of the pulp lifter/ discharger has helped to eliminate material transport issues such as flow-back and carry-over of slurry and pebbles to in-crease the energy efficiency of SAG mill using the actual operational data.

Jan 1, 2014

By Chuanyao Sun, Yang Yu, Zhen Guo Song, Wei. Ming’An

"Carbonate minerals are very important mineral source of extracting metal, radioactive element and rare earth elements. Furthermore,some carbonate minerals, such as calcite and dolomite, are common and important components of sediments and sedimentary rocks. Many flotation processes involve the separation of valuable minerals with carbonate minerals. So it is of great significance to the flotation theory and industrial practice to investigate the flotation behaviors of carbonate minerals. As regulators, metal ions play a major role in minerals flotation. The study of influence law of metal ions on minerals flotation is helpful to eliminate or utilize the effect of metal ions. In this study, calcite and smithsonite laboratory scale flotation, surface analysis and zeta potential determination in the presence of Fe(II) ion were performed to investigate the effect of Fe(II) on carbonate flotation. The results show that Fe(?) depresses the flotation of calcite and smithsonite. The depression effect of Fe species on calcite and calamine flotation can be improved with the increase of Fe(?) concentration. The zeta potential measurements and surface analysis show the existence of iron hydroxide products on mineral surface, which may be link to carbonate site instead of exchanging with calcium on the mineral surface. Fe species on the mineral surface inhibit the interaction between the reagents and calcite/smithsonite through the formation of surface precipitation coating on the calcite/smithsonite surface when the Fe(?) concentration is higher."

Jan 1, 2014

By Ji Hoe Kwon

Hindered-settling column process has been used for the separation of mineral particles for many years. In this study, a model based on DEM (Discrete Element Method) was used to simulate the movements of particles in a settling column separation process. DEM model is capable of describing the motion of particles and calculating the impact forces between particle and particle, and particle and wall contact under various operating conditions. Drag force, rotation induced Magnus lift force, contact force and the gravitational force acting on individual particles were considered for establishing the mathematic models. The overall motion of the particles in water is satisfactorily simulated by the DEM, and the result shows good agreements with the result of lap-scale experiment.

Jan 1, 2014

By M. Zolghadri

MIBC and sodium metasilicate are used as a frother and a dispersant in coal flotation respectively. In order to study interaction between them, flotation experiments were performed on fine coal (<150 microns). It was found that if the frother (MIBC) dosage is in excess of a certain limit, it has an activation effect on the gangue minerals associated with coal. In addition, it was found that however sodium metasilicate can disperse clay slimes eliminating slime coating, but in the case of excess dosage, could intensify activation effect of MIBC, which is undesirable in coal flotation. Keywords: coal flotation, sodium silicate, frother, dispersion, activation

Sep 1, 2012

By Paul W. Weiblen, Louis J. Cabri, Rolando Lastra

"Preliminary tests were done to determine whether comminution by electric-pulse disaggregation, or E-PD (cf. Rudashevsky et al; 1995), was more effective than using conventional crushing for Merensky Reef ore. A hand sample of the Merensky Reef was sawn in two: then one sub-sample was comminuted to .2 mm using E-PD at the University of Minnesota, and the other sub-sample was crushed to .2 mm using a conventional jaw crusher at CANMET.The products of the electric-pulse disaggregation and jaw crusher were fractionated by sieving and by a separation using a heavy liquid with a specific gravity of 3.3, because the proportion of platinum-group minerals (PGM) and sulphides to silicate minerals is very low. Thus, four mineral separates were produced: .2000 + 833 µm, -833 +208 µm, -208-µm float and -208-µm sink. All the mineral separates were studied by image analysis (Lastra et al; 1998). The main objective was to determine the liberation of gangue (silicate minerals), chromite, pyrrhotite, chalcopyrite, pentlandite and PGM. In the case of the PGM, a specific image analysis program was written to search and measure these minerals.The results show that the liberation obtained for gangue was similar (~99%) using either method of comminution. However, the liberation obtained for chromite (~89% vs. ~38%), pentlandite (~50% vs. 1%), pyrrhotite (~56% vs. ~38%), and PGM (~56% vs. ~1%) by E-PD was higher than that obtained by conventional jaw crusher, whereas the liberation obtained for chalcopyrite (~20% vs. ~71%) by E-PD was lower. Nevertheless, the image analysis of the products also showed that the PGM are strongly associated with pentlandite. Thus, for the Merensky Reef, liberation of pentlandite from the gangue minerals and chromite is important to recover more of the PGM. This maybe be significant because, in addition to increased recovery of platinum-group minerals (PGM), Merensky Reef pentlandite also contains significant quantities of valuable platinum-group elements like Pd and Rh (Cabri, 1981; Cabri 1988, Kinloch 1982, Peyerl 1983). Hence, the results indicate that for the Merensky Reef, electric-pulse disaggregation would represent a better comminution operation than a conventional jaw crusher would. In addition, the greatly improved liberation for chromite may find application for the PGM-rich UG2 chromitite."

Jan 1, 2003

The flotation behavior of kaolinite and diaspore using N, N-diethyl dodecyl amine (DEN12) and N, N-dimethyl dodecyl amine (DRN12) as collector have been investigated through flotation experiments. The mechanism of adsorption of two tertiary amine collectors on surface of kaolinite and diaspore were investigated by FTIR spectral, Zeta potentials measurements and calculation of molecular orbital energy. It has been found that DEN12 and DRN12 have stronger collecting power to kaolinite and weaker collecting abilityto diaspore than DDA. Kaolinite and diaspore in bauxite ores can be separated by using DEN12 and DRN12 as collectors at pulp pH below 8 and 6, respectively. The results of zeta potentials and calculation of molecular orbital energy indicated that the adsorption strength on kaolinite surface is in the order DEN12>DRN12>DDA and the adsorption strength on diaspore surface is in the order DDA>DEN12>DRN12. FTIR spectral analysis and Zeta potentials approve that the action between kaolinite and tertiary amine collector is strong electrostatic adsorption and that of diaspore is weak electrostatic adsorption in the range of pH 5~6.

Jan 1, 2014

By Isaak I. Maksimov, Tatyana E. Koltunova, Mikhail F. Yemelyanov, Liudmila A. Otrozhdyonnova

"INTRODUCTIONMetals losses amount up to 50% in coarse fractions in (>100 µm) and composite particles, and to 20- 25% in fine fractions (<10 µm) at non-ferrous floatation concentrating plants of the CIS. Therefore, reduction of metals losses in difficult fractions is of high significance.IMPROVEMENT OF FLOATABILITY OF COARSE AND COMPOSITE PARTICLESReagent regimes with application of strong collectors – xanthates ?5-?8, combination of butyl xanthates and aerofloats ?10-?12, butyl xanthates with hydrocarbons are proposed for this purpose. Application of such reagent regimes for copper and copper-molybdenum ores permitted to increase copper and molybdenum recovery by 0.5-3.9%.Studies, performed by means of specially designed non-frothing flotation machine with independently controlled agitation intensity and narrow size-ranges of air bubbles, established that the best results are achieved with employment of bubbles of 0.5-0.8 mm size regarding particles of any size, with small amounts of up to 2 mm size “transport” bubbles to be expediently used for floatation of coarse particles.Energy dissipation in the main volume of floatation cells must be lower than 0.2-0.25 m2/s3.Performed experiments permitted to formulate requirements to development of machine for floatation of coarse and composite particles. Such floatation machine with volume of 8.5 m3 provided for weak agitation in the main volume of floatation cell and uniform distribution of coarse particles throughout the depth owing to establishing of pulp circulation with upward flows. In addition, in the upper part of floatation cell where agitation is considerably weaker, favorable conditions are created for attachment of particles to bubbles. Testing of this floatation machine demonstrated a 7.5% increase in recovery of +0.2 mm particles in pyrite floatation and a 12-14% increase in recovery of +0.2 mm particles in apatite floatation as compared with a reference floatation machine."

Jan 1, 2003

By Q. Zhang

The flotation behavior of jamesonite was investigated with ethyl xanthate as a collector. It has been shown that jamesonite has good floatability from pH 2 to pH 12, and relatively poor floata-bility at pH>12. The flotation of jamesonite was also dependent on pulp potential at certain pH val-ues. The potential-pH range for jamesonite flotation was established. The FTIR spectroscopy analy-sis and XPS measurement showed that the major adsorption product of ethyl xanthate on jamesonite was lead ethyl xanthate and antimony ethyl xanthate. The intensity of the FTIR signals of metal ethyl xanthate adsorbed on jamesonite and the flotation response of jamesonite were correlated with pulp potentials.

Jan 1, 2014

By Y. M. Zhao

Reutilization of waste printed circuit boards (PCB) can not only prevent potential environmental pollution, but also achieve recycling of secondary resources. Study on recycling of discarded PCB belongs to the front edge of environmental pollution prevention and resource recycling. In order to effectively crushing waste PCB, and solve the problem of secondary pollution of fugitive odor and dust during the crushing process, a wet impacting crusher was adopted to achieve comminution liberation of PCB in water medium. 96.79% of the crushed yield was distributed in ?2mm, and metal took 97.18% in this grade of production. Size distribution of PCB particles was characterized double peaks at the sizes of ?1+0.5mm and ?0.074mm. A double Rosin-Rammler function, is called DRR function, is put forward to describe the size distribution of PCB particles. The DRR function of cumulative weight percentage oversize of PCB was non-liner fitted by self-defining DRR function of the Origin 7.0. The evaluation indexes of the fitting results are the correlation coefficients R2 of 0.9994 and residual E of 0.18671, those show that DRR function is perfectly accurate. Based on the research the mechanical separation and material properties of PCB, a wet process of reclaiming metals from PCB using a new style separator ? tapered diameter separation bed (TDSB) in water medium was designed, and the related separation mechanism was studied. The fluid field of the tapered diameter separation equipment was simulated by the Ansys Flotran software, the variation laws of the velocity in each position in the fluid field as well as the equation of axial distribution sectional max velocity were analysed according to the simulation result, the stress change and motion trajectory of the pellet in the certain fluid field were analysed. The results show that the expanding tubular structure of the varied diameter separation bed indicates gradually decreasing velocity of water flow along the axis, assuming a certain angle in the bed, as a result of the gravity?s influence, and there was corresponding change to the distribution of the flow velocity, thus the whole formed a special fluid field where velocity variations exist in different positions. When the material passed through the fluid field along with the water flow, as a result of the difference to the particle density, the granularity and the shape, there would appear the difference to the motion trajectory as well as the movement distance under the action of the fluid: The lower density materials discharge along with water flow, but the higher density materials would be kept in bottom of the bed and discharge through material mouth. Therefore, light and heavy products were separated effectively according to the density. Using tapered diameter separation bed to process the ?1mm size crushed material of waste printed circuit boards, with the discharge of water 5.5m3/h, feed-rate of the material 250g/min and with an obliquity 35°, product with 93.92% in integration efficiency and 93.73% in recovery ratio of the metal were obtained by the primary separation. Compared with other mechanical methods, the range of particle size was broaden using the TDSB to recovery metals from PCB, and lower limit size of separation almost approach to 0. An innovative process of ?wet impact crushing+ classifying+ tapered diameter separation? recycling metals from waste PCB was developed.

Jan 1, 2014

By Achilles Dutra, Everton Santos, José Oliveira

The beneficiation of phosphate ores by froth flotation is the most efficient process used to separate apatite from gangue minerals like calcite, dolomite and quartz. However, the similarity of surface properties between apatite and calcite generally lead to non-selective adsorption of reagents, rendering the selective separation of these minerals a worldwide problem. The phosphate deposit of Itataia, State of Ceará, Brazil, studied in the present work, presents a complex mineralogical composition having uranium associated with the apatite mineral. The main gangue minerals are calcite and quartz. The bulk flotation of apatite and calcite with anionic collectors in an alkaline medium followed by the selective flotation of calcite at pH 5.5 using phosphoric acid as well as citric acid as depressant have been suggested for this ore. This paper presents the results of contact angle measurements obtained using jojoba oil, a natural reagent composed mainly of gadoleic acid (C20:1) and long-chain fatty alcohols (eicosenol and docosenol), as an alternative collector for the selective separation of apatite and calcite minerals. The hydrophobicity studies were carried out using a computer controlled contact angle goniometer. Additionally, the collector adsorption was evaluated via electrophoretic mobility and FTIR measurements. The results indicated that a high selectivity can be obtained by using jojoba oil as collector in a slightly acid pH range, without the use of depressant. The best results were achieved with a jojoba oil concentration of 200 mg.L-1 at pH 6.5, where the apatite was fully hydrophilic and calcite showed a high hydrophobicity (? > 60 º).

Jan 1, 2014

By Jin Duan, Qi Zheng, Bo Yan, Li-cheng Ma, Xiao-kui Che

"The aim of this study was to develop an approach for the selectively removal of Zn(II) from heavy metal-bearing-wastewaters produced by gold chemical industry using magnetic chitosan based adsorbents. Chitosan beads were prepared by cross-linked modification of Fe3O4-chitosan bead using epichlorohydrin as the cross-linker. Both Zn(II) inprinted magnetic chitosan hydrogel bead (Zn-MCHB) and unprinted magnetic chitosan hydrogel bead (MCHB) were prepared and batch adsorption experiments were used to evaluate their adsorption capacities and selectivities. Single adsorption of Cu2+, Pb2+, Zn2+ and Ni2+ showed that both MCHB and Zn-MCHB adsorbs all the four metals and had an affinity in the order of Cu2+ > Pb2+ > Zn2+ > Ni2+. The binary adsorption revealed that the two adsorbents preferentially adsorb Cu2+/Pb2+ from Zn2+-Cu2+/ Zn2+-Pb2+ binary systems. However, MCHB does not show any selectivity in Zn2+-Ni2+ system. In contrast, Zn- MCHB preferentially adsorbs Zn2+ from Zn2+-Ni2+ binary system. Furthermore, the adsorption selectivity is predictable from stability constants of the metals with the amino group of chitosan. The information revealed in this work can be used for further applications in the treatment of wastewater containing a range of heavy metals from the gold chemical industry."

Jan 1, 2014

The ultimate goal of a mineral processing plant is to recover as much of the target mineral(s) as possible from the ore being treated to achieve the best economics. Selection of the mineral processing techniques is the most important step in achieving this goal. However, due to the complexity of the ore, the recoveries of valuable minerals may be not satisfactory even when the mineral processing technique(s) are well chosen. In other words, minerals of interest can be lost to the tailings for mineralogical reasons. For example, gold is mainly extracted from the ore by gravity, flotation, cyanidation, or a combination of these processes, and high recovery (>90%) can be achieved when gold occurs as coarse grains. However, when a refractory ore is being processed, gold extraction will be challenged by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery mainly include grain size, shape, surface coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking in sulphide, silicate and other minerals as fine-grained gold inclusions and/or as invisible submicroscopic gold is by far the most common factor leading to poor gold recovery encountered in gold ore processing. Processing of PGE ores faces the same challenges as gold. Small grain size and locking of PGM in sulphide and non-sulphide minerals often cause PGM losses. When silver ore contains significant amounts of pyrargyrite, proustite and stephanite, silver recovery by cyanidation can be very low because of the slow dissolving kinetics of these minerals. In the processing of base metal ores, high content of pyrite, intergrowth of chalcopyrite with sphalerite and presence of clay miner-als may cause problems in recovering Cu-, Pb- and Zn- bearing minerals. Process mineralogy helps address all issues and problems related to mineral processing with predicting and trouble-shooting being two major objectives. It provides useful information on process selection, flowsheet development, recovery improvement and reagent consumption optimization. The information acquired from a process mineralogical study can be used as a guide for a metallurgical testwork program for process design or optimization.

Jan 1, 2014

By Xing Yang, Zhen Peng, Guangwen Zhang, Haifeng Wang, Yaqun He

"Triboelectric separation of ilmenite ore based on the tribocharge differences between ilmenite and gangue minerals was conducted in this study. Triboelectric characteristics of ilmenite and its associated minerals were studied using polyvinyl chloride (PVC), pentatricopeptide repeats (PPR), copper, polymethyl methacrylate (PMMA), stainless steel (SS), teflon and quartz glass (QG) tribochargers in lab triboelectric unit. Results demonstrated that the ilmenite particles tribocharged positively while gangue minerals tribocharged negatively using PVC as tribocharger. The particle size also has a significant effect on tribocharge, and the -0.125+0.074 mm is the optimal size fraction of triboelectric separation. Charge-mass ratios of minerals increase with the increases of tribocharging length, but the increasing rate gradually reduce. At 1.5 m tribocharging length, charge-mass ratios of ilmenite, quartz, feldspar and mica are up to 6.07 nC/g, -6.05 nC/g, -4.30 nC/g and -4.56 nC/g, respectively. Based on the triboelectric characteristics of each mineral, triboelectric separation of ilmenite was conducted, and the grade of ilmenite ore increased from 15.47% to 28.40%. INTRODUCTION As a transition metal titanium plays an irreplaceable role in medical, aerospace and materials due to its light weight, high strength and corrosion resistance. Pure titanium dioxide is an excellent white pigment and is widely applied in industries of paint and textile. Ilmenite is the main raw material for titanium industry. For the beneficiation of ilmenite, series methods have been proposed, such as the application of dry magnetic and wet gravity separations to separate the ilmenite from the zircon and rutile. Electrostatic separation is extensively used in the beneficiation of heavy mineral sands for the recovery of rutile, zircon and ilmenite while flotation is used to separate fine ilmenite (Mehdilo et al., 2014; Fan et al., 2014). Compared with flotation and gravity separation, electrostatic separation does not consume water, and native properties of materials will not be changed and energy consumption will be reduced (Wang et al., 2014). Thus, the wide application of electrostatic separation and other dry separation methods is a trend in separation and purification industry, especially in water-scarce areas."

Jan 1, 2018

By S. M. Wen

In mineral processing, the settling of mineral particles in water, the flow of ore pulp, the dewatering and filtering of concentrates and so on, are related to the pulp viscosity. While the interaction between mineral particle surface and water affects directly the pulp viscosity. Therefore, it is of great value to the development of mineral processing theory to research the effect of mineral particle surface on the water viscosity in boundary layer. In micro-fluid, the effect of mineral particle surface on the water molecules in boundary layer can not be ignored. The water viscosity in boundary layer and the effect of the nature of mineral particle solid surface on the viscosity are analysed based on the deduction of attraction potential energy formula of mineral particle surface to the water molecules in boundary layer. The results show that the attraction potential energy of mineral particle surface to the water molecules in boundary layer is determined by the properties of solid molecules and fluid molecules and varies inversely as the third power of the distance from mineral particle surface. The water viscosity in boundary layer consists of the viscosity of free water and the additional viscosity resulting from the attraction of mineral particle surface. The increment of the viscosity caused by the attraction of mineral surface is µs. This additional viscosity is also inverse ratio to the third power of the distance from mineral particle surface. The greater the dipole moment, the polarizability and the ionization energy of mineral particle solid surface molecules are, the higher the attraction potential energy of mineral particle surface to the water molecules and the water viscosity in boundary layer are. The thicker stationary water boundary layer is d0. The higher the µs is, in other words, the greater the attraction of solid surface to water molecules is, the thicker the stationary water boundary layer becomes when free water viscosity is constant.

Jan 1, 2014

By Jan Cilliers

The demand for minerals has never been higher. Moreover, the rate at which this demand is growing is unprecedented, and expansions and new mines will be required to fulfill these growing needs. This, in turn requires a skilled engineering workforce that can develop and operate minerals extraction processes to utilise effectively more complex ores. The International Mineral Processing Council (IMPC) has established a Commission on Mineral Processing Education to consider the global challenge of ensuring an adequate supply of well-trained mineral processing engineers. The Commission has, for the past four years, been collecting international information of the recent mineral process engineering supply position and with a view into the near future. The data collected by the international Commission members are as follows: ? Undergraduate student numbers in minerals engineering ? A breakdown of their male/female ratio ? The fraction of the students from each course that enter the minerals industry ? Teaching staff numbers and age profile This data has been collated and analysed, and the findings are presented. It is clear from the analysis that the supply situation is very different in different regions of the world, and that great opportunities exist for targeted recruitment into the industry to meet the future talent demand. Further, an attempt at correlate the supply of minerals engineers based on the local mineral production rate is shown, which shows that there are clear outliers.

Sep 1, 2012

By P. Harris, D Bradshaw

"Comparison of the two most commonly used classes of depressant in the South African platinum industry is complicated by the fact that these polymers induce different effects on the surfaces onto which they adsorb. The use of carboxymethyl cellulose (CMC), which is ionically charged in solution, can lead to increased particle dispersion in addition to the effect of reduced surface hydrophobicity (depression). Guar is typically only slightly charged in solution. Comparison of these two depressants is complicated since it is uncertain whether differences in their action is a result of either depression of dispersion effects.This work investigates the role of dispersion independently to that of depression in the batch flotation of a platinum bearing ore. An inorganic dispersant, sodium hexametaphosphate (NaHMP) was added in parallel to the uncharged guar depressant to simulate the action of depressants with varying degrees of dispersion. By distinguishing between the material recovered by entrainment and the floatable gangue and by including the effects of froth stability it was possible to decouple the effects of dispersion and depression.The results show that both dispersion and depression led to increased grade of the sulphide minerals. Depression leads to a decreased recovery of floatable gangue minerals. Dispersion leads to an increased recovery rate of these minerals and an accompanying decrease in froth stability."

Jan 1, 2003

By W. L. Jiang

Reverse-flotation technology is often applied in iron ore dressing plant, in order to enhance the quality of iron concentrate from magnetic separation. However, this technology has disadvantages in operating cost, energy consumption, and environmental protection. Developing innovative equipment to process magnetite ore more-effectively is a way to get rid of these disadvantages of reverse flotation and improve the quality of iron concentrate. This paper describes the development of Complex Flashing-Field Magnetic Cleaner, a new kind of equipment based on the principle of combination of separation in magnetic field and separation in gravity field. This innovative equipment possesses a tailor-made magnetic system and has the characteristics of a magnetic field, which can strengthen the formation of magnetic agglomerations and the dispersion of gangue minerals, improving the quality of separation. The automatic control system developed specifically for this equipment can further increase the accuracy of separation and stabilize the process. Test results showed that this equipment is reliable in operation, economically beneficial, and has large potential of application.

Jan 1, 2014

By C. L. Lin

Previous research on particle damage during high pressure grinding roll (HPGR) crushing was limited by the resolution of point-projection micro CT systems and the extent of damage was described by the percent of particles cracked for different crushing methods as determined at a voxel resolution of 40 microns. With recent advances in X-ray optics, the resolution afforded with point-projection micro CT systems has been improved by at least an order of magnitude using a lens-based X-ray micro CT system. With the use of X-ray lens imaging the resolution is determined by the lens rather than by the spot size of the micro-focus X-ray source. The high resolution X-ray micro CT (HRXMT) system made by Xradia with a voxel resolution of less than 1 micron is now being used for the characterization of particle damage during HPGR crushing. In this way, the direct 3-D determination of the internal damage of crushed ore particles which vary from 40 mm down to 100 microns in size is being studied at a voxel resolution of a few microns. The number, size, and shape of cracks can now be measured at this improved resolution and for the first time the specific crack surface area distributions of the crushed product can be calculated from HRXMT images using specially designed software tools for 3D analysis. Results from selected crushing operations are presented. Copper ore particles from HPGR crushing at high pressure (6 N/mm2) are severely damaged having crack specific surface areas as great as 10 mm2/mm3. Keywords: HPGR, particle damage, X-ray micro tomography, crack surface area

Sep 1, 2012

By A. Kogelbauer, A. Stadtschnitzer, A. Boehm, F. Schillab

"The paper covers the design and implementation of an industrial dense medium cyclone plant for carbonaceous iron ore, the proving of efficiency as well as the development of a predictive model for plant control. The VA Erzberg GmbH mines about 12 Mio.t of carbonaceous rock ore at the “Steirische Erzberg”. Due to increased demand of the Austrian steel plants, the production of ore concentrate was raised by 30 % up to 3.0 Mio t/a during the last 5 years. One of the projects to realize the increase in capacity at improved concentrate quality was the implementation of a dense medium cyclone plant for the fine size fraction – 8 +1 mm replacing the former dry permanent magnetic drum separators. By physical separation the siderite variety “spateisenstein” (42% Fe) of a density of 3,8 g/cm³ is separated from ankerite (10 – 17% Fe), the second iron bearing carbonate with a density of 3,2 g/cm³, dolomite, calcite and silicate bearing schists. The feasibility of the process was proven by the test results obtained from a test rig, that was constructed and operated in close cooperation between the Chair of Mineral Processing, Montanuniversitaet Leoben and VA Erzberg GmbH. The density separation surpassed the efficiency of magnetic separation clearly shown by •- values. The plant performance tests (capacity 120 t/h) verify the cut densities defined by Tromp T50 -values and the assigned efficiency found in the pilot tests at varied settings of media density, pressure drop, cone angle and apex diameter. The test rig as well as the final process will be presented. In order to create a tool to predict the performance of the DMS in the centrifugal field at various settings for varying feed composition the experimental results from size and density testing are analyzed in a modified way to obtain physically justified, smooth approximations for the performance curves. Models developed on coal washing plants are checked for their validity at increased densities."

Jan 1, 2018

By Z. Q. He

This paper introduces the structure and working principle of SLon magnetic separator that has excellent performance in iron removal, and summarizes a part of the examples of applications, which applies this machine to remove iron from non-metallic ores, and shows widespread prospect of application of this machine in the purification of non-metallic ores.

Jan 1, 2014