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In this paper High Pressure Grinding Rolls(HPGR) was utilized to pretreat CVRD southern specular hematite for enhancing the pelletization of the refractory hematite. The process parameters of HPGR, balling and firing were optimized, and the mechanism of HPGR was demonstrated by determining the surface activity by means of Blaine specific surface area tester, laser size analysis, scanning electron microscopy (SEM),X-ray diffraction (XRD), micro calorimeter and pelletability index. It is shown that the pelletization of the refractory hematite was greatly improved. The drop strength of green balls increases from 3.4 times to 13.6 times from 0.5m height while the bentonite dosage decreases from 2.2% to 1.3%.The compressive strength of roasted pellets also reaches 2500N/pellet. The mechanism of the pretreatment of CVRD southern specular hematite concentrates by HPGR is revealed that the surface activity is improved by an increases in specific surface area and the amount of micron size fractions, and higher lattice deformation and defects due to the fractures occurring inside particles during static pressure comminution, resulting in more wetting enthalpy, higher pelletability index and good property of roasting.

Jan 1, 2014

By E. Barsky

Physical principles of two-phase flows with a polyfractional solid phase have not received a sufficient theoretical interpretation as yet. Two-phase flows in the separation mode with a counter-flow of particles are even more complicated. Only statistical methods give an insight into general regularities of such processes. These processes can be interpreted best by analogy with the statistical model of an ideal gas developed by L. Boltzmann, although here a number of difficulties arise. The notion of a statistical system for such flows is substantiated. A mathematical estimation of a statistical system is presented. New notions are introduced, namely, potential extraction of a system and lifting factor. A relationship having the physical meaning of entropy is derived for a two-phase flow in the separation modes. The connection of this new entropy with flow parameters, such as the number of particles, separation factor and chaotizing factor, is established. Properties of this entropy are analyzed, as well as the analogy and difference between this entropy and Boltzmann?s entropy. The notion is formulated and the definition of the chaotizing factor of a process is suggested. In the framework of a statistical approach to two-phase flows in the separation mode, the notion of flow mobility has been formulated. Principal regularities of mass transfer in zone/apparatus sys-tem are analyzed. Principal ideas of a cellular model of the process are formulated, and main relationships for its description are derived. Proceeding from the cellular model, a dependence describing the degree of fractional separation of a narrow size grade is found. The analysis of this dependence makes it possible to reveal the crucial role of the Froude criterion for gravitational separation processes. It is found empirically that this parameter is a basis for the affinization of separation curves (Barsky E, Barsky M, 2006; Barsky, 1980).

Jan 1, 2014

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 Kevin Galvin, Simon Iveson

Fine particles are the most valuable because they are the most liberated. However, they are also the most expensive and difficult to recover and concentrate. The Reflux Classifier is a novel invention that combines many of the virtues of existing fine particle separation technologies in a way that provides profound synergies. Multiple parallel narrow channels create a laminar-shear separation zone. The laminar flow provides a well-defined velocity gradient that exposes particles on the wall to a conveying velocity that is approximately proportional to their size, thus reducing the dependence of elutriation velocity on particle size. The high shear rate in these channels generates a hydrodynamic lift force that selectively lifts low-density particles off the channel wall and thus causes them to be preferentially conveyed out in the overflow. Particles that are not elutriated slide back down into the mixing reflux zone beneath the inclined channels which gives them multiple opportunities to re-enter the channels. The resultant suspension of both coarse and fine high-density particles in the fluidized bed zone at the base of the unit generates a strong autogenous dense medium that helps to direct large low-density particles back up to the overflow. The fluidization water also simultaneously de-slimes the high density underflow product. When placed in a centrifuge, the benefits of these features multiply with the improvements in capacity and selectivity that arise from high G-forces. When inverted, these features can be used to perform flotation well beyond the conventional flooding limit. Hence this invention platform has the potential to dramatically improve both gravity and flotation separation performance across the minerals processing industry.

Jan 1, 2014

By B. Das

The processing of banded iron ore by direct anionic and reverse cationic flotation to produce pellet grade concentrate is investigated. This low-grade iron ore, known as banded hematite quartzite (BHQ) contains 41.8% Fe, 41.5% SiO2, 1.2% Al2O3, and 0.5% LOI. The flotation behavior of BHQ is studied by varying the effect of concentration of collector, frother, dispersant and pH. Oleic acid and dodecylamine are used as the anionic and cationic collectors respectively. The parameters that gave the best results in cell flotation are utilized in 100 mm diameter flotation column. All the results are compared with regard to the iron grade and recovery in concentrate. It is observed that, anionic collector with dispersant dosage of 220 g/ton, at pH ~8.5 is selective and yielded a high-grade iron concentrate with low silica as impurity. Also, it is possible to achieve an iron concentrate with 64% Fe at 30-37% weight recovery. The characterization studies of the BHQ ore using X-ray diffraction (XRD) technique and liberation analysis with QEMSCAN® are carried out. The sample contains 58.8% hematite and 37.7% quartz and the liberation of hematite particles are found to be 90.3% in -25 µm size. An alternative statistical modeling approach called response surface methodology was also undertaken to optimize the operating parameters in order to maximize the iron grade and recovery. The predicted results by the model are in agreement with the experimental values.

Sep 1, 2012

By V. A. Chanturiya

The application of High-Power Nanosecond Electromagnetic Pulses (HPEMP) irradiation in dressing of resistant gold- containing ores appears attractive as this technique provides for a significant increase in precious metal recovery (30-80% for gold and 20-50% for silver), therewith helping reduce both energy consumption and the cost of products. The prospects for applying pulsed power technologies in the mineral processing in order to increase the contrast between the flotation properties of raw minerals dictate the need to perform special studies of the effect of HPEMP on the structural state, phase composition, and physical and chemical properties of surfaces of sulfide minerals as the main carriers of precious metals. This study deals with plausible mechanisms of the micro- and nanophases formation on the surfaces of sulfide minerals under the effect of high-power nanosecond electromagnetic pulses (HPEMP) with high electric field strength ~107 V/m. This paper discusses reasons for the changing of flotation behavior of natural pyrite and arsenopyrite during the pulsed-power treatment. It was concluded that HPEMP treatment may be regarded as a tool to change the surface composition and sorption ability of collector (xanthate) onto mineral surface, and, therefore, it allows to control the hydrophobic-hydrophilic surface balance. Single mineral flotation tests have been shown the significant increasing of the pyrite recovery while the arsenopyrite was depressed. The results of gold containing pyrite (pyrrhotite)-arsenopyrite ore flotation in batch approve the decreasing of arsenic recovery in sulfide concentrate. Keywords: pyrite, arsenopyrite, high power nanosecond pulses, activation, selective flotation

Sep 1, 2012

By Massimiliano Zanin, William Skinner, Keith Quast

With the scarcity of fresh potable water on mining sites, particularly those in arid and remote regions, the use of sea water is being contemplated and actually used at a number of mineral concentrators worldwide. The use of sea water, with its associated high dissolved solids content and ionic strength will affect all aspects of processing (e.g. frothing and froth stability, buffering capacity for pH control, solubility of minerals and corrosion of media and equipment). Selective depression of pyrite is more difficult in sea water due to the increased lime addition to achieve a high pH. This results in a reduction in molybdenite recovery. The use of grinding media with various chromium contents and its effect on subsequent Cu and Mo flotation has been investigated in the current study, with both grinding and flotation testing conducted in artificial sea water. Pulp chemistry (pH, Eh and DO) have been logged during grinding, and flotation testing was conducted on subsequent slurries. The flotation results show that the system is remarkably robust and able to cope with wide ranges of pulp chemistry parameters. The effects of artificial sea water on the surfaces of minerals during grinding have been examined using X-Ray Photoelectron Spectroscopy

Jan 1, 2014

By Z. G. Song

As a kind of complex physicochemical process, grinding would affect the subsequent mineral processing such as flotation considerably. In this study, the effect of wet grinding on malachite and calcite flotation using sodium oleate as collector was studied. And the mechanism of the effect of grinding was investigated. Laboratory scale grinding and flotation testing of malachite and calcite samples were performed. Different grinding media were used, including steel balls and zirconia balls. It was the aim of this work to study the effect of grinding on the pulp chemistry paying particular attention to flotation recovery. The effect of grinding media and different addition location of sodium oleate on malachite and calcite flotation was studied. The methodology used in this project involved grinding the ore with and without the addition of sodium oleate in mill, measuring the pH and metal ions produced by minerals after grinding, adding various quantities of sodium oleate and determining the copper recovery. The presence of species of products on the minerals after grinding was probed using X-ray photoelectron spectroscopy (XPS), and the metal ions produced by minerals after grinding were measured by atomic absorption spectrometry (AAS). It is showed that the mil-ling environments evaluated significantly affected the flotation of malachite and calcite. This study also discusses the effecting mechanism of grinding environment on floatability of malachite and calcite.

Jan 1, 2014

By Anuj Narang

Large-scale separation or flotation cells, used in the primary extraction in the oil sands industry, are integral parts of the overall process of bitumen extraction. Good regulation of the interface level between the bitumen froth and the middlings in these cells can result in a significant improvement in bitumen recovery and throughput, and heavily influence process economics. Automatic control of such industrial processes presents challenges such as multi-phase flow dynamics, variable process gain and time delays, poor quality of measurements and significant disturbances. This paper details a case study application of development of multiple models of the dynamics of the interface level and the design of model predictive controllers (MPC) for a separation cell process. A Model predictive controller (MPC) using linear models is designed and implemented in real time on an industrial separation cell. The industrial implementation results show that the MPC scheme provides significant benefits over the current operations which use a PID controller. The benefits include significant reduction in the variance of the interface level resulting in higher bitumen recovery and smoother downstream operation plus energy savings due to reduced underflow pump speed.

Sep 1, 2012

By Willis Forsling, Prabhakar Swarna, Hanumantha Rao Kota

The solubility of wollastonite and its Hallimond flotation behavior as a function of dodecylamine concentration and pH are examined. The flotation response is characterized by adsorption and surface energy in the presence of amine. The methods of UV-Visible and FT-IR spectroscopy for adsorption and sessile-drop contact angle for surface energy estimation are employed. The results of wollastonite dissolution clearly showed its non uniform dissolution. The surfaces are depleted with calcium ions and became rich in silicon within 10 min of flotation time. Maximum flotation of wollastonite corresponds to a half monolayer coverage of amine, which is substantiated by the surface energy parameters. A good correlation between flotation, adsorption and surface energy as a function of amine concentration and pH was observed. The sudden increase in wollastonite flotation and amine adsorption at and above 5x10-5 M initial amine concentration is thought to be due to two-dimensional precipitation of amine on surface in accordance with the recent 2D-3D precipitation model of amine adsorption on silicate minerals.

Jan 1, 2003

By A. V. Neretin

This paper is a continuation and extention of the previous paper on energy-efficient placer mining methods which was presented in 2007 at the World Gold Conference in Cairns, Australia (Nere-tin, 2007a). The paper reports the results only on gravel processing as they were not fully discussed in the previous paper. It is common knowledge that placer gold mining requires processing of large tonnages of gold-bearing gravels by wash plants of different types. In Russia, gold-bearing gravels are mostly disintegrated and screened by the following types of wash plants: a water canon, a derocker or a scrubber trommel. Gold-bearing gravel processing is regarded as highly energy-intensive due to high energy consumption for transportation of large tonnage of material and high pressure water flow rate. The industries requiring a significant expenditure of energy normally estimate the process efficiency by energy consumption per product unit. In order to obtain quantitative data on energy consumption for gravel processing and to estimate placer mining costs, in 2003~2006 four placer gold mines located in the Irkutsk Region were thoroughly investigated through time and motion studies. At all these placer mines gravels were processed by a water canon, a derocker or a scrubber trommel. The objective of the study was to investigate the following parameters: ? wash plant throughput rate per hour; ? hourly diesel fuel and power consumption per cubic meter of gravel processed; ? volume per cent and shape of oversize material; ? different combinations of gravel processing methods. The results from this study were as follows: ? specific energy consumption per cubic metre of gravel processed for different combinations of gravel processing methods was estimated; ? a correlation between energy consumption and unit cost of gravel processing was determined; ? effect of yield and shape of oversize material on wash plant throughput rate per hour was de-fined; ? energy-efficient gravel processing methods were developed. Based on these results, an improved method of gold-bearing gravel processing was proposed. Implementation of this method at a placer mine saved US$ 123 000 in operating expenses only during a short-time Siberian placer mining season. At the same time, this method improved gravel disintegration, screening and processing operations used at the mine. Another advantage of the pro-posed method was higher gold recovery due to reduced yield of undersize material. In order to improve efficiency of gravel processing, a wash system including a derocker for primary gravel processing and a lightweight scrubber trommel was developed. There are two economic benefits of replacing water cannons with the proposed wash system. The first benefit includes lower operating costs for gravel processing due to lower specific energy consumption, while the second benefit is lower gold losses during slurrifying (disintegration and screening) and sluicing of the undersize material.

Jan 1, 2014

By V. Beskrovnaya

Oxidised lead-bearing ores of one of the deposits of Russian Federation represent complex raw materials. Its main components are lead (3.2%~4.7%), silver (100~300 g/t) and zinc (0.7%~0.8%). The sample is characterized as oxidized ore. Silicium (37.4%) and iron (33.2%) are its main com-ponents and present in oxide form. Lead presents as cerussite, anglesite and plumbojarosite have a subject role. Zinc occurs as smithsonite. Certain part of zinc is associated with manganese minerals (psylomelane-pyrolusite). Close association of valuables with manganese-iron mineralization is ob-served. Silver is present in native finely dispersed form. Three options of flowsheets have been developed to recover valuables from the ore. 1. Hydrometallurgical flowsheet of lead and silver recovery on the basis of chloride leaching. 2. Flotation. 3. Flotation -flotation tailings cyanidation. Hydrometallurgical flowsheet of ore processing on the basis of chloride leaching (option I) al-lows to achieve recovery into saleable products of 68.8% Pb and 70.2% Ag. High quality lead concentrate with 71.7% lead and 700 g/t silver was obtained during flotation (option 2). Flotation tailings cyanidation (option 3) provides 24% silver additional recovery (from the ore). Technical and economical evaluation demonstrated that ore flotation (option 2) and flotation with subsequent flotation tailings cyanidation (option 3) are the most cost-efficient. Option II is the most cost-efficient variant of 1 tonne of ore processing (9.05 US dollars).

Jan 1, 2014

By G. Bulut, Ü. Yenial

"Heavy metals contamination in aqueous systems can be found in a variety of industries, in particularly mining, metal processing, finishing and plating. Water containing more than 0.5 ppm heavy metal considered as a toxic due to harmful effects on health. The major techniques employed for heavy metal removal from industrial wastewaters include precipitation, reduction, ion-exchange, and adsorption. Adsorption is a heavy metal removal method for aqueous systems. As a common adsorbent, activated carbon has been used in treatment but it is ineffective on some elements. Thus, there has been a research for developing highly effective and selective adsorbents. In this study the adsorption of lead and arsenic ions on to coal waste and red mud waste was studied. The experimental parameters were determined as pH, equilibrium time and the initial concentrations, activation by heat treatment and the blend of adsorbents. According to their adsorption capabilities, red mud was found to adsorb lead and arsenic ion with high efficiency but coal waste did not adsorb arsenic ion. However the binary adsorptions of these ions were enhanced the adsorption efficiencies. In addition the blend of coal waste and red mud affected the adsorption efficiency. INTRODUCTION As a result of rapidly developing industry and excessive use of water resources, the need of clean water and wastewater management appear as a problem. Wastewater recycling activities and researches come to the fore for an effective use of wastewater. Recycling of wastewater, which contains heavy metals harmful to the environment and human, is a difficult process. Heavy metals are generally divided into three categories: toxic metals, precious metals, radionuclides. Wastewaters from various industries, containing heavy metals, are the main polluters of water and soil. Although their toxic structures, heavy metals are used extensively in industry as they have technological significance. Usually mining industry, metal industry and industrial organizations produce heavy metal containing wastewaters (Volesky 1990, Ting and Lawson 1991, Bishop 2002)."

Jan 1, 2018

By S. M. Javad Koleini

Processing of phosphate ore sample was investigated for increasing phosphate content and reduction of its gangue minerals such as carbonates and silicates. Experimental designs were per-formed using Taguchi method. Different flotation methods were investigated for Moundon phosphate ore sample and three methods were used as follow: direct cellophane flotation, reverse calcite flotation and reverse quartz flotation. Because of the sensitivity of cellophane flotation to slime content, prior desliming was carried out before the experiments. Direct flotation experiments carried out and a concentrate contained 23.80% P2O5, 6.88% SiO2 and 72.33% recovery were produced. The achieved P2O5 content in the produced concentrate from reverse flotation of calcite was 26.44% and the recovery was 82.56%. The concentrate products obtained at optimum conditions by direct flotation of phosphate and indirect flotation of calcite were subjected to indirect flotation of calcite and direct flotation of appetite and final concentrates with P2O5 grade of the order of 24.19% and 26.96% were obtained, respectively. It was concluded that one stage direct flotation is unavoidable to achieve a product with low SiO2 content.

Jan 1, 2014

By W. D. Guo, Y. M. Zhu, B. B. Luo

The main chemical constituents of waste cooking oil are higher fatty acid glycerides, which can be used to produce anionic fatty acids for most non-sulfide flotation. However, using the mixed fatty acids (MFA) produced by waste cooking oil as collectors directly, the flotation effect is usually not satisfactory, especially at lower temperature or room temperature. There are very rare systematic studies about the reason for poor flotation performance of waste cooking oil. This study aims to investigate the flotation and adsorption characteristic of different types of fatty acids in waste cooking oil to find out what kind of fatty acids results in the poor flotation performance. This will provide technical supports and theoretical guidance for the waste cooking oil application in the field of mineral processing. In this study, MFA were produced from the waste cooking oil, and then separated into saturated fatty acids (SFA) as well as unsaturated fatty acids (UFA), which possessing different flotation properties. The properties of the MFA, SFA and UFA were analyzed by iodine value, melting point measurement, Fourier transform infrared (FT-IR) spectroscopy and quartz micro-flotation tests. The results showed that UFA was composed of fatty acids containing group—(CH=CH—CH2)n—, having an iodine value of up to 162.90, a melting point as low as -17.3 ? and stronger low-temperature floatability. In contrast, the SFA was made up with saturated fatty acids and a few oleic acids, with an iodine value of 48.97 and a melting point of 38.8 ?. SFA had shown poor collectability and required a flotation temperature higher than 35 ?. The results of zeta potential measurements, solution chemistry calculation and FT-IR spectra revealed that both UFA and SFA can be adsorbed on the quartz surface activated by CaCl2 via the chemical and hydrogen bonding. The reason MFA having a poor flotation performance is the SFA has an extremely high melting point which affecting the dissolution of the dispersion.

Jan 1, 2018

By Xiaolu Ye

"Comprehensive utilization of Bi and Sn from the tin-associated polymetallic tailings by “gravity separation – flotation combination process” has been studied, which was verified that the novel process is an effective method to deal with the high content pyrrhotite tin-associated polymetallic tailings. In this investigation, ore property analysis and magnetism analysis of pyrrhotite were conducted to research and develop reasonable beneficiation flowsheet. The results of ore property analysis present that pyrrhotite was not closely related to bismuth and tin minerals. Particle size analysis results indicated that pyrrhotite was mainly in the form of fine particles. The magnetic analysis results show that pyrrhotite was distribution in all the three types of pyrrhotite in a single mining area, which indicated that variable magnetism of with different crystal structure pyrrhotite. The process of “low intensity magnetic separation - high intensity magnetic separation” shown an excellent adaption for the high content pyrrhotite tin-associated polymetallic ore compared with the single flotation process based on the magnetism variable of pyrrhotite. The results of whole process test indicated that a bismuth coarse concentrate assaying 5.63% of Bi at 81.77% recovery was obtained, which treat the conditions for the Bi-S separation flotation. In addition, the content of sulfur in the tin concentrate decreased from 2.5% to 1.5%, which provided a new reference for other tin-associated polymetallic tailings. INTRODUCTION Tin has been applied extensively in catalytic chemistry, gas sensors, tin plating, and plumbing. Tin-bearing polymetallic ores have been the important deposit types to recycle tin with the rapid depletion of mineral resources. The comprehensive utilization of the associated elements has been a preoccupation for the mineral processing researchers."

Jan 1, 2018

By B. Peszko

There are many measuring methods of grain sizes. Taking into consideration the fine grained materials, one of the existing techniques is measurement of grain size by the Coulter Counter method. This method is based on the measuring the changes of electrolyte resistance during grains flow through the calibrated diaphragm. This method is relatively simple to apply, significantly precise and the results are given quickly. However, the problem is that the measurements are limited by the size of diaphragm. Because of this situation, measurement of grain sizes by this instrument is possible in range from 10% to 60% of diaphragm diameter. This limitation causes the necessity of re-placing diaphragm in case when the measured grain size distribution concerns the material of large size range. In purpose of determining the total grain size distribution, the synthesis of some partial distributions, given for individual grain fractions (with different diaphragm applied), is required. This is possible to do by calculating the mixture of distribution functions, created from the partial distribution functions. Two materials were selected to research: quartzite and glass, which were comminuted in cylindrical crusher, additionally grinded, screened and then analyzed by Coulter Counter for five grain fractions: 0~125 µm, 0~80 µm, 0~56 µm, 0~40 µm and 0~25 µm. For each fraction, five different partial distributions were given (in case of glass ? four), which are the basis for the creating the joined grain composition. To assure the adequacy of the given distribution function, it is necessary to obtain the possibly best approximation of partial distributions. In the work, both the parametric and non-parametric methods of density approximations of investigated random variable. For each grain fraction the approximations were done by three traditional distribution functions: RRB, GSA and log-norm distribution functions and three methods of non-parametric approximation: Gauss kernel, Epanechnikov kernel and orthogonal Fourier series method. As the criterion of the certain distribution function acceptance, the value of the residual deviation was assumed, given by the formulae:

Jan 1, 2014

By Q. Zhang

Phosphate tailings through Flotation contains large amount of dolomite which is difficult to be separated from apatite. In this present research, phosphate tailings is recycled by Flotation i.e. re-processing. High-purity dolomite with purity as high as 91.17% is seperated, which contains 19.82% of MgO. The results of orthogonal test show that the effect of various levels of different factors on the high-purity dolomite floatated. Future utilization of purified dolomite is also discussed: magnesium fertiliser especially magnesium phosphate is expected to be an ideal product from high-purity dolomite.

Jan 1, 2014

By Georges Delemontex, Nigel Grigg

"Pre-concentration of precious metal and base metal ore types is becoming more relevant with the discovery, development and operation of many lower grade deposits around the world. The fluctuations in metal prices and currencies expose many mines to risks especially dealing with low and variable ore grades. Pre-concentration, the process of concentrating the valuable metal into a smaller mass yield, effectively results in the introduction of higher feed grades to milling circuits. Gangue rejection, the removal of lower S.G. waste rock from the circuit, not only results in higher downstream grades but also potentially removes harder, non-valuable mineral, providing significant power savings within the circuit. The pre-concentration or ‘gangue rejection’ process offers a number of benefits when considering the treatment of marginal ore deposits, especially if it can be performed at a coarse crush size; these benefits include a reduction of the operating costs and the feed of more metal units to the mill. Gekko Systems has effectively utilized the Inline Pressure Jig (IPJ) to pre-concentrate the valuable metal, achieving high primary recoveries into a range of mass yields resulting in upgrade ratios between 2 and 10 times. This paper explores: the benefits of pre-concentrating ‘marginal’ ore deposits prior to the milling circuit; the selective rejection of ore types that may affect either the recovery or comminution process; and also looks into the potential to effectively reduce the ‘cut-off’ grade when considering the mine planning process. Case studies of projects using the IPJ to pre-concentrate and reject gangue are also included. Pre-concentration and gangue rejection provide the potential to develop marginal ore deposits, thus providing higher grades, less gangue and more metal at a lower operating cost to producers."

Jan 1, 2014

By H. R. Manouchehri

"In all electrical beneficiation methods, the difference in electro-physical properties of the contributed mineral particles, essentially frictional charge, electrical conductivity and dielectric constant properties are exploited to achieve separation. The composition of the raw material determines what kind of either corona charging, conductive induction, or triboelectric separation method should be employed. The process is versatile and is influenced by different parameters related to mineral characteristics, surrounding ambient conditions and electrical and mechanical attributions of the separating device. Electrical separation is surface based beneficiation method which is mainly affected by the surface and surface changes of the minerals. Therefore, it is essential to understand how the electrophysical properties of the minerals can be changed/modified. During electrical/electrostatic separation process, both charge magnitude and its polarity that developed on the particles and therefore, their electrical beneficiation potential is essentially defined by surface phenomena. Therefore, it is essential to understand how the main electro-physical parameters can be changed/modified with applied surface treatment/pretreatment methods to promote separation. Surface treatment of minerals is carried out by different means, including chemical conditioning, irradiation, thermal treatment, etc. This paper discusses and analyze the electrical separation process, electrophysical properties of the minerals with special focus on the effect of surface pretreatment/treatment methods to affect electrical beneficiation potential of the minerals. The surface treatment methods vary in a wide range from simple surface cleaning to more complicated chemical conditioning and doping. The knowledge of the solid-state physics and chemistry leads to improve the beneficiation potential of different mineral systems by choosing suitable treatment method(s). Despite the complexity and multiplicity of the charging mechanisms, difficulties in separating fines it seems to be beneficial make our attempts to further investigate and develop the process as dry, low cost beneficiation process, especially nowadays when environmental concerns, as well as energy and water consumptions are main concerns for mining industry."

Jan 1, 2018