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By Bertil I. Pålsson, Sture V. Persson, Kent T. Tano

"Grinding is one of the most energy consuming unit operations and is also a very inefficient and costly process. Therefore, it is of great importance to run the grinding process as efficiently as possible. The most common way today to control grinding processes is by measuring the power draw of the mill and try to keep it at a maximum level. However, some studies (Kawatra, 1989, Koivistoinen, 1989, Moys, 1989) have shown that this measurement doesn.t reflect everything that takes place inside a mill. Among other parameters like slurry rheology, temperature and charge behaviour, the volumetric filling of a grinding mill seems to have a large influence on the grinding efficiency (Herbst, 1988, Koivistoinen, 1992, Vermeulen, 1988). A problem in attempting to measure those parameters has been to get a sensor that is both robust and sensitive enough for continuous on-line measurement.This paper presents a method for the measurement of the apparent filling level in a pilot ball mill equipped with the Metso Continuous Charge Measurement system (CCM). In this technique a strain gauge sensor is mounted on a flat steel spring which is fitted into a recess underneath a lifter bar. In addition, a conductivity probe, the Boliden Grinding Measurement System (GMS), is mounted in another lifter bar with the purpose of comparing the two measurements. To visualise the behaviour of the charge a DEM modelling technique is used.The results indicate that the system is capable of following the normal variation that occurs in the mill. The signal also very well reflect changes in operating variables such as ball charge level, pulp density and rotational speed. By studying the nature and different features of the signal one can get a better understanding of milling circuit dynamics. Another feature of the technique is the possibility for an operator to continuously follow the grinding process and thereby run the process under optimal conditions."

Jan 1, 2003

By M. Brozek

The constant of flotation velocity is the value characterizing the kinetics of cyclic flotation. In the statistical theory of flotation its value is the function of probabilities of collision, adhesion and tearing off the grain from the air bubble. The grain ? air bubble collision plays a key role since there must be a prior collision before the grain ? air bubble adhesion happens. The probability of such an event to occur is proportional to the relation of the grain diameter to the bubble diameter. When the grain sizes are given, it is possible to control the value of collision probability by means of the size of air bubbles. Consequently, it is significant to find the effect of physical and physicochemical factors upon the diameter of air bubbles in the form of a mathematical dependence. In the pneumo-mechanical flotation machine the air bubbles are generated by the blades of the rotor. The dispergation rate is affected by, among others, the rotor rotational speed, the amount of air transported to the flotation chamber an time and the liquid surface tension, depending on the type and number of applied flotation reagents. In the proposed paper the authors will present the distribution of air bubble diameters on the grounds of the above factors, according to the laws of thermodynamics. The correctness of the de-rived dependences will be verified empirically.

Jan 1, 2014

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

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

Jan 1, 2018

By Aidan Giblett, Karen McCaffery, Robert Dunne

"A worldwide decline in competency levels of practicing metallurgists over recent decades has become clearly evident and is a common topic of discussion among senior practitioners and professional associations. The associated impacts on the industry are material and include operational inefficiencies, missed optimisation opportunities and suboptimal new plant designs. There are many contributing factors to this condition. Decrease in competency is particularly evident both in regions where imbalance between supply and demand has led to a general reduction in experience levels for comparable roles over time and in emerging regions where a rapid rise in demand for practitioners has occurred in conjunction with rapid economic development and industrialization. The context, depth and breadth of education curricula and levels vary with location such that solutions to the technical competency dilemma may need to be developed specifically for each region with these influences in mind. Delivering, demonstrating and maintaining competencies are a critical requirement of undergraduate training and ongoing professional development. Other factors such as generational and cultural characteristics and expectations, political influences, role requirements and employment reward and recognition systems all play a critical role in determining if core competencies can be effectively developed, applied and subsequently maintained. This paper reviews factors impacting and some common approaches to competency development. The authors’ experiences in the management of professional development efforts within the global industry are reviewed and a blueprint proposed to address industry requirements in this area."

Jan 1, 2014

By W. Y. Liu

A sulfate reducing bacteria strain (named SRB-A) is isolated from sanitary wastewater by using anaerobic technology of Hungate. The studies of physiological, biochemical and phylogenic of the isolated strain are carried out. The colonies of the strain are circle. Cells that are slightly curve, rod-shaped with the size of 1.0~3.0µm in length and 0.8~1.0µm in width. The optimum temperature for growth of the organism is 30~35°C. The optimum pH for growth is 7.0~7.2. Strain SRB-A can use sodium lactate, sodium citrate, sodium acetate, ethanol and acetone as electronic acceptor but can not use glycerol, glucose, sucrose and sodium oxatate. The isolated strain reduces sulfate, sulfide, sulfur, DSMO and FeCl3, then nitrate and nitrite can not be used. The strain has higher tolerance of NaCl, and the optimum growth occurs in the presence of 5%~8% (w/v) NaCl. The result of 16S rDNA sequence analysis indicates that the isolated strain SRB-A is the most similar to Desulfo-vibrio halophilus, and the level of the similarity was 98.4%. The isolated strain has a stronger ability to reduce sulfate, and the level of sulfate reduction reaches about 90% at pH 7 in the liquid medium. 0.6 to 0.8 is the optimum COD/SO42- in the medium for the isolated strain to show better ability to reduce sulfate. At pH 2.5 the level of removal of Cu2+ reaches 96.3%. Under the condition of pH 3.5, the level of removal of Zn2+ reaches 92.6%. When the value of pH reaches about 7, the Fe3+ is precipitated by the formation of Fe(OH)3, and Fe3+ is removed up to 89.4% at last.

Jan 1, 2014

By E. V. Zelinskaya

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

Jan 1, 2018

The Arctic is a region of special economic, geopolitical, research, socio-ethnic, and defense interests of both Russia and other countries of the Arctic zone. Introduction of innovation technologies at ore-processing factories is a direct responsibility of the state and this problem should be solved on the basis of coordination of interests of different stakeholders. The task of elaboration of scientific principles of rational state regulation in the North is very topical. Innovations require considerable investments first of all from private capital. However as an investment object innovations are not attractive for investors as they require large expenditures for long-term projects, and they are connected to high risks because market incentives form striving to get quick profits of private companies and result in a certain behaviour strategy while innovations need ?long money?. Under such conditions without state regulation of investment and innovation activities development of the mining sector in the Arctic practically has no prospects. At innovation development of mining enterprises economic growth is provided at the expense of active state innovation activities. The elaborated strategy of ore-processing enterprises should correspond to the modern paradigm of the ore-processing industry development which is not only for extraction of minerals but also for multi-profile structure having comprehensive use of the resources on the rational basis intended for rational complex utilization of mineral resources of the AZR which by the definition includes maximally full use of the whole aggregate of resources on the economically rational basis with obligatory environmental with resource reproductive and socio-economic functions and deterrents. The main principle of creation of innovation technologies is to obtain more products of higher quality with minimal costs. This allows increasing ?productivity of the resources? several times. This principle makes increasing productivity of the resources the most important and in this case efficiency of use of the resources brings extra profits at the expense of lack of new costs such as payment for protection and utilization of wastes. According to the economic theory only ratio between demand and supply is able to fix optimal proportions in economy and to give necessary signals for investment activities of mining enterprises. In this context market for minerals and increase of mineral resources productivity do not create incentives for investment activities without which neither sustainable economic growth nor solution of macroeconomic tasks are possible. Nevertheless countries should not reject this idea in spite of economic efficiency of the enterprises. Extraction degree of useful components and especially oil in the Arctic zone is one of the lowest in the world. This can lead to crisis of oil industry and other mining sectors. The reason for that is lack of a state policy of realization of innovation technologies in the mining sector in the Arctic.

Jan 1, 2014

By V. Hudecek

Problems of sudden outbursts of rock and gas present in deep mine mining ones of the most complicated interrogation. It is searching for the methods of prediction and prognosis that can be most useful for the government of these phenomena. Till now the pressure and the desorption of gas in bore holes was consider to be the decisive criteria. By the work of authors with using of statistical date was verify that for considerable reliability of forecast and prevent outbursts is necessity investigate characteristics of workplace and other indicators. These indicators were analyzing and assemblage into mathematical dependences which represent active and passive force asserting with in the process of rush. It was validated by using the equations which are presented in the manuscript that the accuracy of pre-diction of the phenomena is higher and methods of preventions are better also.

Jan 1, 2014

By P. Coghill, P. Revell

"Geo-sensing is the ability to routinely measure or infer rock properties at a range of scales using non-destructive scanning devices. These devices can provide information and data flows to support integrated decision making across the minerals value chain. Geo-sensing has been used for many years in minerals exploration using technologies such as satellite imaging and airborne geophysics but to date the use of sensing technologies in between the mine and mill has been very limited. The aim of this research is to develop new mineral sensing technologies that can enable grade engineered ore streams through the rejection of low value gangue or deleterious elements either in the pit or during transfer to the mill. This paper focusses on the research and development being carried out by the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) and its associated members on new sensing technologies. At the start of their development these technologies were classified on the Technology Readiness Level scale at 3 (TRL3), equivalent to a proof of concept. Laboratory testing and design is aimed at progressing these sensing technologies to TRL5 which is ready for testing at an end users site. New data obtained during the laboratory testing and design phases are presented in the paper demonstrating performance specifications such as detection limits and measurement speed which can be used to infer the pod size of gangue that can be rejected at scale. Grade Engineering® and coarse gangue rejection are considered as key drivers for the mining industry to address the higher mining, processing and environmental costs associated with ore bodies with declining grades. This is an industry wide problem and the development of mineral sensors is seen as key enabling technologies for Grade Engineering® and coarse gangue rejection. The technologies presented in this paper enhance value through early decision making of ore quality and improve the overall resource value case through improved grade and throughput engineering."

Jan 1, 2018

By H. M. Yang

Structural alteration of pyrophyllite during mechanical activation in a planetary mill was investigated by X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. Mechanochemical effect markedly promotes the decrease in reflection intensities with increasing the grinding time. Prolonged grinding causes the pyrophyllite to become the amorphous structure. It can be indicated that pyrophyllite is very susceptible to alteration by grinding. Crystal size (d006) of pyrophyllite appears to be a limit after 2h grinding. IR spectroscopy analysis shows a little alteration in the bands of pyrophyllite after mechanical activation. The results indicate that the ordered structure of pyrophyllite is destroyed and lattice deformation occurs. Porous silica was then successfully prepared via leaching the mechanically activated pyrophyllite. Pyrophyllite was first ground for 6 h. Ground samples were subsequently leached with 4 M hy-drochloric acid at 80 °C for 2 h to produce porous silica with specific surface area of 188.1 m2/g, total pore volume of 0.18 mL/g and average pore size of 3.9 nm from N2 adsorption analysis. Otherwise, the porous silica obtained from direct leaching of the original pyrophyllite only has a specific surface area of 4.3 m adsorption analysis. 2/g and total pore volume of 0.03 mL/g. It is inferred that grinding is favorable for the formation of microstructure pores. It offers a simple and convenient route for the preparation of porous materials from natural minerals.

Jan 1, 2014

By W. Fander, Zhonghan Zhang, T. Choo, J. Enraght-Moony

"This paper describes the mineralogical and metallurgical procedures used to determine the recovery and concentrate grade of heavy oxide minerals occurring in lode deposits. The data produced also provide vital information to the processing engineers, which allows them to develop the most suitable flow sheet for that particular heavy mineral, here called an Economic Oxide Mineral (EOM). It demonstrates how results are interpreted to ensure that the proper process is used at each treatment stage to optimise recovery and to produce the most suitable concentrate at that point. Reference is made to some of the current equipment and techniques that can be used to process EOMs. The paper shows that when assessing the economic potential of a new ore body, or existing ore treatment plant, ore characterisation (OC) is necessary. This is especially true for EOMs such as cassiterite (SnO2), wolframite ((Fe, Mn, WO4,) pyrochlore ((Na,Ca)2Nb2O6(OH,F)), and tantalite (MnTa2O6) where often what seem to be small changes in ore types can have major effects on recovery and concentrate grade. Due to advances in flotation technology scheelite (CaWO4) in some deposits can be less vulnerable to OC variability than other EOM’s. Thorough mineralogical examination is shown to be the fundamental basis of correctly undertaking OC. This is because mineralogical analysis identifies each of the steps required to ensure that all ore types and zones are recognised, and differences explained, and shows the benefit in using reference samples to compare differences in the ores. The OC methods used for EOMs containing metals such as tantalum, tin, tungsten and niobium are similar; if two or more of these EOMs occur in one deposit as separate minerals, then OC will show when and how these minerals should be separated. The OC techniques described for EOMs can also be tailored for other heavy minerals, precious metals and graphite."

Jan 1, 2014

By Peng Qian, Xiao Li, Guoyan Fu, Peiwei Han, Yongliang Wang, Shufeng Ye

"Arsenic removal from high arsenic gold concentrate is conducive to increase the mineral value and realize the mineral comprehensive utilization. This study investigated the alkaline pressure oxidation leaching (APOL) of an arsenical gold concentrate in lower temperature to separate the arsenic into filtrate. The effects of temperature, NaOH concentration, solid-liquid ratio, reaction pressure and stirring speed on the leaching efficiency were investigated, and the characteristics of the gold concentrate and leaching residues were evaluated using XRD and SEM analysis methods. The obtained results showed that by using lower temperature (<60?) it is possible to avoid the production of elemental sulfur during the leaching process, which is benefit for the oxidation of arsenopyrite; When the reaction was carried out under appropriate conditions, more than 98% of the arsenic will be extracted into the filtrate as the form of arsenate or thioarsenate. INTRODUCTION In recent years, there has been considerable interest in the recovery of gold from refractory arsenical gold ore. The arsenic in this kind of ore usually exists as the form of arsenopyrite, and the gold surrounded by arsenopyrite exists as the form of fine particles, which will give many difficulties to metallurgical work. When the content of arsenic in the gold ore is more than 0.5%, it will seriously penalize the smelting efficiency (Ruiz et al., 2014). So pretreatment of the refractory gold ore is necessary to obtain the largest economic value and environmental benefits (Balaz et al., 2000). The oxidation pretreatment processes mainly include roasting oxidation, pressure oxidation, chemical treatment and biological treatment (Ann et al., 1992; Kou and Chen, 2012; Tongamp et al., 2010; Fernandez et al., 1995; Lin and Zheng, 1996). Among them, the roasting oxidation and pressure oxidation are the more ordinary processes in industry. The roasting oxidation process is the mature and adaptable technology, but the production of waste gas containing sulfur and arsenic will pollute the environment. The pressure oxidation method possesses certain metallurgical and environmental advantages, and can efficiently decompose the mineral. According to the different solution media, the pretreatment can be divided into alkaline and acidic pressure leaching pretreatments (Papangelakis and Demopoulos, 1990; Hiskey and Sanchez, 1995). The acidic pressure oxidation method has been used in most smelting plants for high arsenic gold ore pretreatment, while the alkaline pressure oxidation is still not widely applied. Compared with the acidic pressure oxidation, the alkaline pressure oxidation can be realized under lower temperatures."

Jan 1, 2018

By L. Gao, X. Gui

Fine coal obtained from Kailuan mine served as the processing object of this study. This material was difficult to separate. A flotation rate experiment was designed to investigate the process distribution characteristics of size and density during fine coal flotation. Size and density analyses of five clean were studied. The mineral morphology of flotation rate experiment cleaning was observed through scanning electron microscopy. The fractions -0.074+0.045 mm and -0.045 mm exhibited the best practical floatability and presented the highest combustible body recovery rates, but the selectivity and natural floatability of these two fractions were the worst. The - 0.074 mm fraction has contaminated the clean coal from the early stage of flotation, and the cumulative clean coal ash of -0.074 mm reached up to 17.20%. The low and middle-density classes displayed varying flotation behavior, but the flotation yield difference was only nearly 3%. The middle-density class caused the clean coal to have high ash content. The poor selectivity of fine coals, middle-density fraction, and fine mud resulted in high-ash clean coals during flotation. Thus, improving the selectivity of fine coal, restraining the flotation of fine mud, and grinding the coal to decrease the middle density mass fraction to liberate clean coals can yield high-quality clean coals through flotation.

Jan 1, 2014

By Å Sandström

Loussavaara-KiirunavaaraAB?s (LKAB) iron ore mine, Kiirunavaara, is of magnetite type and associated with apatite, a calcium phosphate mineral. Rare earth elements (REE) have been found in connection with the apatite but also in other minerals. An apatite concentrate was produced by flotation, in order to investigate the possibilities to extract REE from the apatite by hydrometallurgical means. The content of rare earth elements calculated as oxides (REO) was 0.44% in the concentrate. Initially, leaching was done with large excess of sulfuric acid, hydrochloric acid, and nitric acid to study the REE solubility with different acids. In sulfuric acid, the leaching recoveries of the different REE varied between 35% and 69%. The reasons for the relative low recoveries, were that the rare earth elements precipitated together with huge amounts of gypsum, that was formed during leaching. However, both hydrochloric- and nitric acid gave almost complete extraction of the REE into solution. Analysis of the small leaching residue obtained, revealed, that mainly the light REE remained in the residue indicating that a small part of the light REE were present in the concentrate, in some acid, insoluble mineral other than apatite. With the aim to separate the REE from the phosphoric acid, the solutions from hydrochloric- and nitric acid leaching were neutralized to a pH of approximately 2 with ammonia. During neutralization, REE were precipitated as phosphates with good recoveries and a concentrate of 10.5% REO suitable for further upgrading was obtained, while the remaining solution can be used for fertilizer production. In further solvent extraction studies, it was shown, that after re-dissolution the REE could be effectively extracted by Cyanex 923, thus allowing for purification from calcium and phosphate ions. The REE were finally stripped from the organic phase and a REE nitrate solution was produced. Keywords: apatite, rare earth elements, REE, leaching, solvent extraction, cyanex 923

Sep 1, 2012

By T. Neesse

In many cases, the use of hydrocyclone control is desirable for the stabilization of separation in the setting of changing feed conditions. Control concepts based on exact mathematical models are not satisfactory due to the complexity of the physical process. In this case, fuzzy control is a suitable solution. The data are primarily derived from an optical sensor that monitors the outside view of the free underflow stream. A throttling valve, serving as an actuator, is installed in the overflow pipe that regulates the volume split of the cyclone. Applications in closed circuit grinding and in separation plants for tunnel driving, fine sand dewatering, and classification of kaolin demonstrate the typical use of this development. Additionally, the technological characteristics of the cyclone may be improved by this control, which is mainly caused by the increased discharge capacity of the un-der flow nozzle. A further advantage is the option to operate at an optimal operation point. In many cases, this point is located at the transition spray/rope discharge. The improved operation characteristics present new options for extensive applications of fuzzy cyclone control.

Jan 1, 2014

By P. S. Rao

In 1951, Tata Steel became the pioneer in Asia by setting up its first ever washery in West Bokaro Colliery. The first beneficiation plant used to produce clean coal of 19% ash with chance cone. Feed size of chance washers were -75 mm to +6 mm. The fine coal (-6 mm) were used directly. With change in technology,in 1986,chance cones were replaced by DM cyclones and coal was washed in two circuits. In the coarse circuit -13 mm to +0.5 mm coal was washed in two stages while the fine coal of -0.5 mm was treated in froth floatation cell. With further improvement in the process the higher ash raw coal was feed to produce clean coal of 13% ash. In 1998, DSM cyclones were replaced by scrolled Evolute design cyclone which has Ep of 0.020 to 0.025 ranges resulting in increase efficiency of separation. With the increase in demand of clean coal, lower seam proportion has increased in raw coal production. The washability studies of individual seams indicated large difference in the seam characteristics in terms of washability and specific gravity cut points of the individual seams. So washing all seams together had resulted in frequent change in the character of coal and warrants frequent changes in the operating parameters of the plant in which the separating efficiency comes down and ultimately resulted in yield loss initially. With increase in knowledge and experience in coal washing the solution to this problem was achieved by adopting, seam-wise washing which is enabling process engineers by keeping set point for longer periods there by to enhance the separation efficiency. Keywords: coal processing, froth floatation, steam washing

Sep 1, 2012

By A. I. Urvanzev, N. V. Shikhov

"In this paper, we present the study’s results of electrical separation processes on the basis of new separator designs, new technological solutions, and newly discovered effects. We considered the options of enrichment by magnet separation of magnetite and titanomagnetite ores, ores and products containing chromium and manganese, ores of non-ferrous and precious metals. During pneumo-electric separation of mixed iron ore of SMPC, 43.3% of the output of the concentrate with an iron content of 61.7% was obtained in one step, with extraction of 70.5%. The paper also presents the results of the finalization on the air-electric separator of the magnetic fraction when separating oxidized ores of MPPOO (mining and processing plant of oxidized ores) on the Jans polygrade magnetic separator. A concentrate was obtained with an iron content of 65.1% with the extraction of 95.0% and tails with an iron content of 13.0%. The possibility of obtaining low-silica concentrates from these ores with an iron content of 67.15 and a quartz of 2.88% is shown. Also, the results of tests on the enrichment of chromite ores on the firing-magnetic scheme with corona-electrostatic separation are considered. On the initial ore of the Don MPP (mining and processing plant), a concentrate with a content of 61.8% Cr2O3 was obtained with a quartz content of ~ 1.0%. The results of pneumo-electric separation with triboelectric charge of the separated particles are presented. The results of the tests indicate a principal possibility of enriching chromite ores without costly high-temperature roasting. Dry technology of enrichment of manganese ores with the use of electrical separation increases the quality of the oxidized concentrate to the first grade and raises the total extraction by 2 times. For the Chineya deposit of titanomagnetite ores with copper impurities, electroseparation operations were carried out on two samples with a Cu content of 1.93 and 3.75%, respectively. For a sample with a Cu content of 6.02%, a copper concentrate output of 24.42% was obtained with a Cu content of 23.82% and the extraction of 94.88%. The results of enrichment by electroseparation of gold-containing sulfide ores can have the practical importance. For ores of the Berezovskoye deposit, a pyritic concentrate containing 100 g / t of gold was obtained after two or three operations of IES (integrated energy systems)."

Jan 1, 2018

By P. Bevilacqua

In this paper the possibility to complete the copper recovery and to enrich in PVC a mixture of plastic granules obtained by grinding electrical cables are investigated. The recovery of a large part of the copper still present among the plastic granules was possible by means of a mechanical screening, the finer polymeric fraction was collected, at the same time. In order to complete the copper polymer separation the following techniques were employed. Counter current separation in water, static dense medium separation with zinc chloride solution and copper extraction with nitric acid and subsequent electrolytic deposition. A Tri-Flo® dynamic dense medium separator was employed in order to separate the lighter polymeric fraction, from the heavier polymeric fraction, mainly PVC. Water or a salt-water solution was employed to feed the separator device.

Jan 1, 2014

By M. N. Chandraprabha

Arsenopyrite is often associated with sulphides like pyrite, chalcopyrite and galena in refrac-tory gold ores. Selective flotation of arsenopyrite from associated sulphides is desirable for effective gold extraction when the gold is preferentially associated with the arsenopyrite matrix. By contrast, presence of arsenopyrite in flotation tailings poses a serious environmental threat due to arsenic dissolution. To prevent arsenic contamination from the mine wastes, it would be more economical and environmentally beneficial to remove this mineral during the froth flotation step. Use of Acidithiobacillus thiooxidans in the detoxification of arsenic containing sulphides is outlined in this pa-per. Biomodulation using Acidithiobacillus thiooxidans resulted in the preferential depression of pyrite from arsenopyrite. By suitable conditioning with cells and collector effective separation of arsenopyrite from pyrite was achieved. Biomodulation with wild cells did not yield separation of arsenopyrite from chalcopyrite. However, bacterial affinity could be induced to a desired sulfide mineral through environmentally controlled adaptation techniques. Through the use of arsenic-adapted bacterial cells, selective removal of arsenopyrite from chalcopyrite was readily achieved.

Jan 1, 2014

By Kari Niiranen

LKAB (Luossavaara-Kiirunavaara AB) is operating iron ore mines, concentration plants and pelletizing plants in Northern Sweden. The largest of the apatite magnetite deposits and the mines are Kiirunavaara with annual production rate of approximately 27 Mt crude ore underground. LKAB produces two varieties of pellets: blast furnace pellets and direct reduction pellets (LKAB DR Oxide Pellets). Meanwhile the concentration process in a sequence of the low intensity magnetic separation (LIMS) and flotation at the concentration plant. In spring 2007 there were noticed great fluctuations of SiO2 grade in the crude ore. The high SiO2 grade is particularly problematic in the case of direct reduction pellets. In consequence, a project was started (called Silica in the Mine) to define exactly the problem related with silica and to find out, if possible, the reason for the great fluctuation of SiO2 grade in the crude ore going to the processing plant. A further target of this project was to develop a simplified method at the laboratory scale, to predict SiO2 grade in the magnetite concentrate in the future, but also predict the physical properties of the ore with respect to mineral processing. The essential stage of systematic characterization of the ore body for mineral processing properties is the estimation and simulation of different parameters from the laboratory scale to the large scale at the concentration plants using empirical data collected at the mineral processing by LKAB in Kiruna. Further a target was also to find useful physical parameters for mineral processing and implant those parameters into the existing geological 3D-model of the deposit. This information will be used for making prognosis of the future mining and the quality of the crude ore. It will also give better control and improve the production planning in the mine and the performance at the concentration plant in Kiruna concerning the decrease of the SiO2 grade of the magnetite concentrate.

Sep 1, 2012