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By A. Mainza, H. Hill, L. S. Bbosa

"Impact breakage is the most elementary size reduction mechanism in comminution devices. In comminution research, characterization of breakage is primarily concerned with the energy expended to cause it. The main challenges of this approach have been quantifying the actual energy requirements of impact breakage and developing mechanistic models to accurately describe the process. For engineering load analysis, fracture is characterized in terms of strengths such as yield stress and ultimate tensile stress, which govern the maximum loads specific materials can be subjected to before irreversible inelastic deformation and subsequently complete fracture occur. With this approach, the main challenge has been to elucidate the underlying mechanism, in the means that the load causes weaknesses in the material microstructure to act as sites for stress concentrations, leading to crack initiation, propagation and eventual failure. Studies dedicated to investigating particle fracture under impact loading have led to the development of several devices for conducting breakage characterization tests. These devices include the drop weight tester, split Hopkinson pressure bar, rotary breakage tester and the short impact load cell. All these have different particle loading and breakage methods, and thus can yield distinct information which can be compiled together to study a material and the nature of breakage. This work analyses the single impact breakage data obtained across the listed devices. A homogenous ore commonly known as blue stone is used for all breakage tests. The work is conducted using standard procedures specific to each device as closely as possible. Drop weight and rotary breakage tests were used to obtain hardness parameters based on an existing t10 breakage model, while split Hopkinson pressure bar and short impact load cell measurements provided properties based on conventional engineering load analysis. The results were used to highlight the significance of the loading geometry, impact mechanism and impulse on the extent of breakage."

Jan 1, 2018

By R. J. Batterham

The science and practice of mineral processing has been driven for many years by the same set of challenges that shape the mining industry ? demand and supply, grades and their decline with time, mineralogy and the need to handle more complex ores, disposal and minimising of wastes and the availability of water, power, skilled labour and the like together with increasing expectations from the community, concerns on sustainability and safety and, as well, climate change forcing a more targeted approach on energy. In this paper, the author builds on previous reviews to the IMPC and suggests that while step changes are long overdue, the unprecedented demand mitigates against drastic changes. That said, the ?Mine of the Future? is already requiring some different approaches.

Jan 1, 2014

By N. ??dyanik, Z. Kugukaldinova, O. Mishurina, Y. Glazkova, E. Mullina

"This paper describes the process flow of a selective processing method for acidic mine waters formed in the copper sulfide industry and characterized by a high content of copper, iron, and manganese ions. The proposed method comprises a series of sequential processes: the 1st stage is the recovery of Cu2+ ions by precipitation, the 2nd stage is the recovery of Fe2+ and Fe3+ ions as a dispersed phase by acid-base precipitation, followed by recovery in the 3rd stage of Mn2+ ions by converting Mn2+ with an oxidizing agent into insoluble forms of manganese and subsequent recovery of the dispersed phase by electroflotation. The developed method was tested on the acidic tailing storage facility (TSF) water of a mining project in the Urals region. The practical results of the implementation of the developed method have shown that its implementation will allow to recover copper, iron, and manganese in the form of salable products with a simultaneous decrease in their concentrations in adjacent water bodies down to the applicable MPCs. The process is a simple one, does not require any sophisticated expensive equipment and can be implemented either as a standalone solution or as part of existing treatment facilities. INTRODUCTION As a result of unsustainable utilization of natural resources in Russia, only a small fraction is processed into commodity products, while the rest is systematically dumped as emissions, effluents, and other wastes, polluting the environment. By amount of waste and concentration of valuable components, those wastes can be classified as aqueous technogenic resources [1, 2]. Therefore, the development of processing methods for this mineral resource category is an urgent and priority task that will significantly improve the industry’s profitability and the environmental conditions in the respective regions. MATERIALS AND METHODS Following research methods were mainly applied in this study: lab-scale and pilot-scale tests in a diaphragmless two-chamber electric flotation cell; for solutions and recoverable process products — chemical analysis using photometric determination techniques for metal cations and atomic adsorption determination techniques for the processing products. The phase composition of the precipitates formed in the process was investigated by X-ray phase analysis in the general-purpose diffractometer with a copper anode DRON-1."

Jan 1, 2018

By Kozlov Andrey, Matveeva Tamara

"The results of mineralogical and technological studies of platiniferous dunites from Svetloborsky zonal massif (Urals platinum belt) are presented and the basic typomorphic signs of productive mineral assemblages are substantiated. The characteristic features of platinum ore mineralization are revealed: a wide range of iron-platinum alloys, enrichment of ore-formed system by the elements Os, Ir, Rh and activity of the S and As in it, intrusion of Fe-Ni sulfides in platinum and its fusion with magnetite. More than 80% of PGM mineral grains has size less than 100 microns, that determines the possibility of significant losses of platinum in the process of gravity separation and the need for additional recovery processes for small and fine fractions of platinum tailings and sludge products. Summarized results of laboratory tests of small-volume sample processing of platiniferous dunites are presented and the processing flow sheet is developed and tested. The flow sheet incorporates several stages, including stage-wise grinding and gravity separation of ore using the centrifugal concentrator Knelson KS-MD for differently sized material and flotation treatment of tailing products using new classes of reagents for additional recovery of PGM fines."

Jan 1, 2014

By Reinol Compañero, Ivy Gonzales, Herman Mendoza, Brian Buenaventura

"The extraction of gold in the Philippines has been a significant challenge for the past decades. Around 70-75% of gold mined in the country can be accounted from the small-scale mining industry which primarily use the traditional cyanidation and amalgamation; processes which have been advocated due to its adverse affects to health and environment. To address this challenge, an alternative clean and sustainable technology was developed for the small-scale miners to recover gold and other metal/mineral values efficiently from Philippine ores. An initial survey was conducted and followed through with extensive mineralogical investigations ascertain the best method applicable. It was determined that Philippine gold occur in ore as (1) very fine particles in the microns range, (2) free-milling, which is in abundance, and (3) locked particles with sulfides --- it was concluded that enhanced gravity concentration and flotation are viable alternatives. A comprehensive test regime was followed to check the response of the ores obtained from different small-scale mining districts across the country. It was shown conclusively that the gold ores respond positively, with recoveries using gravity concentration and flotation of at least 95% and 88%, respectively; exceeding the nominal recoveries using cyanidation or amalgamation. A specific process flow was designed for each type of ore with customized parameters. It was determined that while capital expenditure of implementing these alternative processes is higher than what is currently being used, the operational aspects show that it is much more economical to apply enhanced gravity and flotation. It should be noted that the process developed addresses the critical issue of environmental costs which should be more than enough to justify the shift from the current to the novel and sustainable technologies."

Jan 1, 2014

By T. Fujita

The incinerated bottom ash includes titanium oxides and a small amount of chromium oxides. Initially, 89 % of chromium was removed from ash at magnetic flux density at several stages of wet magnetic separation from 0.05 T to 6 T. The bottom ash from an industrial waste incineration process includes about 10 % of TiO2. The minerals that contain titanium are rutile and perovskite. These minerals are paramagnetic and show low magnetic susceptibility, therefore, the high magnetic field strength, created by a superconducting magnet, is necessary to capture these minerals. At the first stage of separation, a magnetic field strength of 6T was applied in order to attract the particles that contain iron oxides to the higher magnetic field region. At the second stage of separation, the magnetic capture rate of weekly magnetic particles decreased with increasing the magnetic susceptibility of the aqueous solution (i.e. the medium for dispersing the particles) in order to separate the highly magnetic materials. The para-magnetic salt such as ferric chloride was dissolved in the water to increase the magnetic susceptibility of the medium. After a two-step wet HGMS with superconducting magnet, the grade of TiO2was increased from 10 % to 28 % with a recovery of 64 %.

Jan 1, 2014

By E. V. Koporulina, I. Zh. Bunin, M. V. Ryazantseva

"We studied the mechanism of structural and chemical transformations of columbite, tantalite, zircon and feldspar surface during the treatment by high – power electromagnetic pulses (HPEMP) using the methods of X - ray photoelectron spectroscopy (XPS), analytical electron microscopy (SEM - EDX), Kelvin probe force microscopy and flotation experiments. According to XPS and SEM - EDX data, major changes in the atoms chemical state of investigated minerals surface are related with formation and modification of functional cover and changing in concentration (% at.) of hydroxyl groups on the mineral surface, leading to increase in the contrast of technological properties of the rare metals minerals. Research has identified the optimal parameters of HPEMP - treatment of rare - earth minerals Npuls ??104, Ttreatment ??100 sec. improving the selectivity of the flotation separation of columbite and zircon. The difference in mineral recovery into the froth (? e) before and after HPEMP - treatment was about 11 % and 24.5 %, respectively. No significant increase was observed in the flotation activity of feldspar. This study's findings demonstrate the effectiveness of HPEMP - treatment in inducing a controlled change in the structural and chemical properties of rare - earth minerals and improving the process efficiency for the processing of rougher tantalum - niobium gravity concentrates.INTRODUCTIONThe importance of improving the processing methods of tantalum-niobium ores and concentrates is explained by the mineralogical properties of rare - earth ores. These are properties such as the variable mineral, chemical, and grain size composition, complex morphometric properties, and the dissemination of ore mineral grains of micro - and nanometric size. Iron oxide and hydroxide films on the mineral surfaces neutralize the surface physicochemical and absorption properties of the minerals. Both in Russia and globally, nonconventional (non - mechanical) methods are being developed based on physicochemical, electrochemical, and pulsed energy impacts to improve the efficiency of disintegration and liberation processes of disseminated mineral complexes and to enhance the contrast of the structural, chemical, and technological (floatability) properties of refractory ores. This study is devoted to the investigation of the applicability of high – power electromagnetic pulses (HPEMP – treatment) for the change in the structural and chemical properties of rare - earth minerals and improving of the flotation properties contrast."

Jan 1, 2018

By Sun Chuanyao, Cao Fei, Sun Desi, Zhou Dezhi

"The research applies the density functional theory and molecule design technology to design and synthesize the novel flotation collectors for copper-sulphur separation. Density functional theory (DFT) was applied to investigate the electronic properties of O-isopropyl-N-benzyl thionocarbamate (IP-BIAN) and O-isopropyl-N-ethyl thionocarbamate (Z-200). The calculation results show that both the energy of highest occupied molecular orbital (EHOMO) and the lowest unoccupied molecular orbital (ELUMO) of IP-BIAN are smaller than that of Z-200, electronegativity of IP-BIAN is higher than that of Z-200. According to the Klopman’s generalized perturbation theory, the collecting power of the two compounds is predicted to be Z-200 > IP-BIAN, the selectivity of IP-BIAN is better than that of Z-200. Then the thionocarbamate molecular is synthesized, and the compounds are characterized by nuclear magnetic resonance (NMR). It turns out that the test result identifies the prediction after the flotation verified test of pure mineral and actual mineral. The results demonstrate that the EHOMO and ELUMO are smaller in the thionocarbamate after a nitrogen atom is bound to benzyl, the thionocarbamate has strong selectivity and low collecting power. The lower the LUMO energy of thionocarbamate is, the stronger the back donation covalent p-bond between collectors and chalcopyrite is, thus improving flotation power for chalcopyrite and selectivity against pyrite. The result proves the feasibility of design and synthesis of the novel thionocarbamate through the frontier orbital properties of the collectors.1. INTRODUCTION Thiocarbamate is a kind of nonionic polar collector and is now widely used as flotation collector for copper-sulphur separation. The flotation power of thiocarbamate to chalcopyrite is stronger than pyrite, so it has high selectivity against pyrite. The frontier orbital theory and density functional theory (DFT) has been widely applied to study the structure-activity relationship of flotation collectors [1-6]. The flotation test results can be interpreted by using the reaction energy criteria and quantum-chemical parameters, such as the energy of the highest occupied molecular orbital (EHOMO) and the energy of the lowest unoccupied molecular orbital (ELUMO) of collector [7-11]. In turn, there are rarely reports about screening the novel flotation collector, by the frontier orbital properties such as HOMO and LUMO of flotation collectors. In this thesis, we apply the density functional theory and molecule design technology to design and synthesize the novel flotation collectors for copper-sulphur separation. Based on the previous findings of the structure-activity relationship of xanthogen formats [12], it has stronger collecting ability to chalcopyrite while the xanthogen formats after a nitrogen atom is bound to benzyl. Thus, in this study, a novel thionocarbamate molecule O-isopropyl-N-benzyl thionocarbamate (IP-BIAN) will be constructed, when the group structure connected with N atom in the known collector O-isopropyl-N-ethyl thionocarbamate (Z-200) is replaced with ethyl by propyl. The collectors (IP-BIAN and Z-200) have been calculated by DFT methods in quantum chemistry. By analyzing the reaction energy criteria and the frontier orbital properties (HOMO and LUMO), this research predicts flotation performance of novel collectors (IP-BIAN), then the synthetic experiments and flotation verified tests are conducted. The research provides a new theory reference for screening out the high-effective flotation collectors of copper-sulphur separation. This technology adoption will contribute to the sustainable development of mineral resources as it shortens the research cycle of new collector molecules and reduces the investment."

Jan 1, 2018

By V. Z. Kozin, E. A. Bekchurina, P. S. Volkov, Yu. P. Morozov, A. S. Komlev

"The current sampling systems of ore flows or concentrates are based on the method of cross sections in point sampling and the method of scooping in reducing. The limited number of point samples in sampling and microsamples in reducing lead to big random and probable systematic errors. The paper defines the principles of sampling, which assure the absence of systematic errors and also provides calculation formulas of probable errors in sampling methods of cross and longitudinal sections as well as in samples preparation. The article sets the fundamental laws of sampling: the dependency of minimal mass of gross sample and number of point samples from mass of point sample in sampling from heterogeneous body; the dependency of a sample minimal mass from lumps’ size in preparation of carefully mixed samples; the dependency of point samples’ dispersion from duration of control period. The paper introduces the fundamental notions: lump variance; probable systematic error; methodical error. It also provides a solution of outstanding sample correct application in analysis results calculations. In application of automatic analyzers, mounted in material flows, the probable error connected with sampling, is calculated by the formulas for carefully mixed sampling bodies. The paper describes the developed and introduced sampling systems on the base of combined application of cross and longitudinal sections methods in sampling and preparation of samples. The advantages of this equipment are compactness, reliability, simplicity in service and operation, and for pulps it is adaptability in pipelines. Application of the developed equipment entirely excludes probable systematic error. The new systems of sampling and preparation of samples are introduced at 25 concentrating plants. Introduction of the developed systems at sampling balance points of concentrating plants allowed double reducing balance deficiency."

Jan 1, 2018

By S. M. Viduka

This paper presents a numerical investigation of solid separation in jigging device, which is a gravity separation method widely used in ore processing. Separation is recognized as being heavily dependent on fluid motion in the jig. This study explores the effects of the inlet time dependent velocity profile on jigging performance. Modelling of the liquid-solid system is performed through a combination of computational fluid dynamics (CFD) to simulate liquid flow and discrete element method (DEM) to resolve particle motion. The initial packing conditions consist of a binary-density particle system of 1130 particles each 1 cm in diameter. A variety of jigging profiles are implemented in jigging. The saw tooth pulsation profile is selected with three variations in both amplitude and frequency. The performance of each profile variant is compared in terms of solid flow patterns, separation kinetics, energy, and mean particle position. These quantitative comparisons demonstrate significant differences in the segregation rate, energy, and solid phenomena, helping find an alternative optimum operating setting for the system.

Sep 1, 2012

By N. Vasumathi

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

Sep 1, 2012

By Milind Chikhale, Ranjeev Kumar, Keshav Tyagi

Ore characterisation including mineralogy and beneficiation testwork of an ore is very important for determination of possible products and their quality. The results of such study help in ascertaining the beneficiation process route for the ore. The present study deals with ore characterisation study and beneficiation testwork on the samples of hematite iron ore with goethite impurity. The characterisation study reveals that the hematite is under alteration stage to goethite which has become an integral part of hematite. High goethite/limonite content is enhancing the loss of ignition content of the ore and reducing its Fe content. The findings indicate that in case of hematite iron ore associated with goethite and limonite, it is difficult to achieve high grade of concentrate above 65% Fe. It depends on the amount of goethite and limonite minerals and their association with hematite. These minerals contain aluminous impurities and hence, their rejection becomes essential. Separation of limonite and of goethite to limited extent is possible. In case of goethite, effective liberation is not achieved where it occurs as surface alteration product of hematite grains. The gangue mineral reported are clay and gibbsite, and are closely associated with iron minerals. The test work results indicate the grade and recovery of Fe along with alumina and silica content in lumps, sinter fines and pellet feed fines that can be achieved for the different ore types vis-a-vis the percent of available hematite in the ore. The recovery of iron is dependent on the hematite available and the loss of iron values in tailings is more because of rejection of limonite and goethite.

Jan 1, 2014

By P. Vijay Kumar

Phosphate minerals are conventionally concentrated by flotation process using soap or soap- light diesel oil emulsion as collector. Some plants use detergents such as sodium petroleum sulfonate or alfa olefin sulfonate to enhance efficiency of soap flotation. It is reported that urea a known hydrotrope enhances flotation efficiency of soap as efficiently as alfa olefin sulfonate or linear alkyl benzene sulfonate at bench scale tests. In the present study tri sodium citrate also a known hydrotrope is tested as promoter in the flotation of phosphate mineral from Eshidiya ore.

Sep 1, 2012

By J. K. Afidenyo

Microbial pretreatment of a double refractory gold ore was investigated using a white rot fungus, Coriolus versicolor (ATTC 20869) to improve gold extraction. A series of preliminary tests were conducted to determine the amenability of the ore to fungus degradation. Pulp density, temperature, pH and retention times were the process variables considered. Both a single. Stage and two-step processes were studied to establish process conditions. During the single stage process, the ore was contacted with the fungus culture (biotic) for 3weeks at 30°C and pH 10.0. For the two-step process, the first step involves ore contact with the culture medium (abiotic) at 45°C and pH 10.0 followed by fungal contact (biotic) at 30°C. Results indicated that carbonaceous matter is not degraded but passivated by the fungus; as preg-robbing activities dropped significantly from 18.1% to below 1.0%. The single stage process resulted in higher gold recovery than the two-step process Gold ex-traction by cyanidation of the pretreated ore was 78.9% for the single stage compared with 15.0% for the untreated ore. In the two-step process, only 73.3% gold extraction was achieved. Application of the two step process conditions to a high grade flotation concentrate, resulted in 93.3% gold ex-traction as against untreated concentrate of 30.5%. The results show that the microbial pretreatment process degraded sulfide sulfur, passivated carbonaceous matter and enhanced gold extraction from double refractory gold ore and concentrate.

Jan 1, 2014

By Tamara F. Kondrateva, Evgenia E. Savari, Galina V. Sedelnikova, Rauf Y. Aslanukov, RAS (INMI), Grigori I. Karavaiko

"The investigation is dedicated to study of biohydrometallurgical processing of refractory gold-arsenic concentrate with the large content of pyrrhotite. Sulfide concentrate of chemical constituents: 75g/t Au, 4,7g/t Ag, 6,3% As, 29,3% S, 2,3% Sb, 0,5% ? (organic) and of mineral composition, %: 11,8 arsenopyrite, 39 pyrrhotite, 12 pyrite, 2,9 antimonite and the rest – aluminosilicates, carbonates and quartz, was studied. The recovery of gold from concentrate by cyanidation is 51,2%. The rest of gold is embedded as finegraded segregation in sulfides.Sulfide oxidation process study is described. Bacterial oxidation was executed on a pilot laboratory unit using combined autotrophic bacterium: A. thiooxidans , A. ferrooxidans, Leptospirillum ferrooxidans and sulfobacillus thermosulfidooxidation, pH=1,5-2,2, t=28-32?C, oxidation time 120 hours. Pyrrhotite is the least stable sulfide mineral with electrode potential 0,45V versus arsenopyrite (0,55 V) and pyrite (0,55-0,6 V) and is oxidated primarily. Pyrrhotite oxidation is followed by large amount of elemental sulphur, which has a bad influence on cyanidation.It’s established that the rate of arsenopyrite (for the first 48 hours) from concentrate containing 39% pyrrhotite is 2-3 times as less as the rate of arsenopyrite bio-oxidation from concentrate without pyrrhotite. The arsenopyrite bio-oxidation is accelerated only after the elemental sulfur was oxidized by bacterium A. thiooxidans and elemental sulfur percentage was reduced from 6,8 to 3,9%. The bacterium concentration is increased from 2,5x107 to 2,5x109 cells/ml. Almost full oxidation of arsenopyrite (98%) and pyrrhotite (98- 99%) is finished in 120 hours. We have studied two pretreatment methods for elimination sulfur content influence on cyanidation: aeration in lime and electrochemical treatment. Such an operation enables to have supplemental oxidation of elemental sulfur and other oxygen and cyanide absorbants before cyanidation. After treatment the content of elemental sulfur was decreased from 3,9 to 2,2%, gold recovery from 90 to 96% and cyanide consumption from 16,2 to 7,2 kg/t decreases. The content of toxical rhodonite-ions in liquid phase of pulp and disinfection reagents consumption were decreased as result of elemental sulfur content in bio-oxidated product reduction."

Jan 1, 2003

By I. Ngoma, Marijke Fagan, Susan Harrison, Rebecca Chiume

"Heap bioleaching is an unsaturated hydrometallurgical extraction process which is commonly applied to the recovery of copper from low grade sulfide ores as well as for preparatory treatment of gold ores. The leaching reactions occur in the liquid phase, catalysed by iron and/or sulfur oxidising micro-organisms. Contact of the mineral grains with the leaching solution is consequently essential for metal recovery. Additionally, the liquid is responsible for the transport of the liberated metal out of the heap under gravitation-driven flow. However, the highly inhomogeneous structure of the heaps coupled with low irrigation rates cause the flow to vary between being gravitationally and capillary dominated, resulting in non-uniform wetting of the ore. In this study a 132 kg agglomerated ore ‘slice’ is used to examine the effect of liquid distribution on microbial colonisation and mineral recovery in a long term bioleach (> 500 days) when irrigation from a single drip emitter source is employed. The novel setup enabled sample collection from ports positioned along the length and height of the ore bed, so that 2D maps of the degree of wetting and microbial colonisation could be generated at different times in the leach. Lateral movement of the liquid increased with bed depth; the majority of flow was below the irrigation point while the top corner of the bed that was not irrigated remained the driest region of the heap throughout the experiment duration. The lowest cell numbers were also recorded in the driest regions. Specifically, cell numbers in the top corner of the bed, 400mm from the irrigation point, remained at undetectable levels until the 283rd day measurement, in line with typical heap operation durations. This indicates that slow colonisation of the heap in the regions between irrigation points may be a significant issue in heap optimisation."

Jan 1, 2014

By Xubo Chen, Zhiqiang Hu, Zhijian Sun, Gaoyun Zhou

"The research aimed at developing an efficient and environmental frother,which was applied in the flotation of sulfide ores. The flotation properties of an efficient frother and pine oil have been studied relatively by flotation tests of lead and zinc sulfide ores. At the same time, the biodegradability of two kinds of frother has been studied by the method of biological respiratory curve. The test results show that the flotation properties of new frother are superior to pine oil such as flotation rate, dosage etc. and its biodegradability is superior to pine oil. INTRODUCTION Frother is a kind of important agent in flotation reagents.In practice, the criterion of the foaming performance of the frother is what is high and low according to flotation indexes. The difference of different minerals and flotation technologies has great influence on the foaming performance of frother, and it is very important to choose the corresponding frother. The type, dosage and selectivity of frother in flotation process must be considered carefully. In today's society, environmental protection and ecological protection are becoming more and more important, and the environmental and ecological damage from mine development has aroused increasingly more attention. The use of mine agents has promoted the development of mineral resources, greatly improves the recovering utilization of mineral resources, at the same time, the production and use of mine reagents also inevitably bring about pollution, and result some influence or damage in the ecological environment.The frother is a common kind of reagent in the flotation process of the concentrator. In many cases, the waste water in the concentrator can not be let out in the natural water because the higher content of the frother in the waste water results in higher index of COD.This will inevitably increase the cost of waste water treatment in the mine.Therefore, the choice of frother should not only consider its influence on the flotation index, but also consider its influence on environmental protection. Waste water treatment is a way to solve the waste water pollution, but it needs to cost a lot of fund, manpower and material resources.And the development of high efficiency pollution-free reagent is a good way to reduce the production cost of mining enterprises and reduce the environmental pollution."

Jan 1, 2018

By Caroline Olsen

The objective of this study was to achieve Zn activation control in an industrial Cu flotation circuit treating a complex Cu-Pb-Zn-Au-Ag sulphide ore at the LaRonde Division of Agnico-Eagle Mines Limited (Québec, Canada). In order to provide process relevant results, a laboratory testing methodology was developed to duplicate plant operational parameters. The action mechanisms of ZnSO4, TETA (triethylenetetramine) and NaHSO3used as depressants in order to limit ZnS activation were examined. Laboratory flotation tests with and without Cu2+ions (the ions responsible for ZnSactivation)were performed. All depressants showed equal or better flotation performance relative to baseline tests. For example, in the presence of Cu2+, the Zn recovery reduced from 32.2% to 17.5% in the copper rougher concentrate after adding ZnSO4(with a dosage of 50 g/t). TOF-SIMS analyses confirmed the relative decrease in surface Cu in the samples treated with ZnSO4and TETA. For the case with TETA, this indirectlyindicates the formation of a copper TETA complex in solution, thereby reducing available Cu for transfer. The TOF-SIMS and XPS data indicate that the addition of ZnSO4and NaHSO3resulted in an increase in surface metal hydroxides and SO3 on ZnS grains inhibiting both Cu and collector attachment.ZnSO4 was subsequently tested with success in the LaRonde concentrator. The addition of 40 g/t ZnSO4 at the conditioning (or cleaning) stage led to a 2% reduction in Zn content in the Cu and PM concentrate. Recently, improvements towards the control of copper sulfate addition in the downstream Zn flotation circuit resulted in the reduction of Cu2+ in process water. As this ?cleaner? water is recycled for Cu and PM flotation, the addition of ZnSO4 is now used only as required.

Sep 1, 2012

By Gorki Davila, Irineu Brum

"Brazil has large reserves of coal (32 billion tons) located predominantly in the south of the country. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently the country's strategic planning aims to minimize the gap between coal and resources traditionally used in the Brazilian energy matrix. In this scenario the processing of Brazilian coal by flotation appears as a promising alternative, having been successful in mineral systems containing fine particles This paper aims to study the overall process of flotation for a specific Brazilian coal. The material used in this study consists of fine coal that is usually discarded as waste and deposited in the tailings dam. The objective is to recover carbonaceous matter and reduce the ash and contaminants grade. The variables analyzed were the influence of size particle, solids concentration in the pulp, the concentration of surfactants and frothers to be used. The results showed that it is possible, from a feed with around 65% of ashes, to obtain products with approximately 35% ashes with mass recoveries about 40%. The types of collector reagent and foaming employees result in different concentrates. This study also presents a preliminary analysis of the effect of water recovery in concentration parameters."

Jan 1, 2014

By Y. J. Ferdosi

This paper presents the outcomes of the preliminary investigation focused on the potential usage of Electrochemical Impedance Spectroscopy (EIS) in minerals processing. Currently, Electrochemical Impedance Spectroscopy has been successfully employed in the characterization of multilayer structures formed as molecules adsorb on flat surfaces and is commonly used in bio-related research. Few studies have explored the application of EIS in minerals processing, particularly for mineral particles and flotation systems. In the first series of tests, the impedance response was investigated as a function of particle size, shape and hydrophobicity using model quartz particles. The particle size fractions and the shape were found to contribute to the impedance response. The more hydrophobic quartz particles resulted in a higher impedance values. Further tests involved pure sulfide minerals including chalcocite, bornite, chalcopyrite and pyrite. The AC impedance measurements were conducted as a function of collector (sodium ethyl xanthate) dosage. The AC Impedance data was modeled using the combination of reference circuits. It has been shown that adsorption of collector onto sulfide minerals surfaces results in a higher magnitude of impedance. Increasing the collector dosage resulted in an increase in AC impedance for chalcopyrite, while a decrease was observed for chalcocite. Significant variations in impedance were exhibited by bornite and pyrite with a gradual increase in collector dosage.

Sep 1, 2012