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By Nirmal S. Weerasekara, Malcolm S. Powell, Mohsen Yahyaei

"An understanding of the fundamentals of different breakage mechanisms is critical for successfully modelling comminution processes. Due to the high frequency of low energy collisions in the grinding process, superficial breakage has a significant role in size reduction in mills. To develop a scaling up methodology for characterising low energy surface damage behaviour of ores, a series of surface damage tests have been conducted using three grinding mill sizes with diameters of 1.8, 1.2, and 0.8 m. Two types of gold-copper ore with different hardness were used: C-ore and T-ore. All tests were conducted using wet mode to remove the products during grinding. To ensure low energy surface damage was the dominant mechanism, in all tests the mill speed was reduced to 40% of critical speed. A surface damage index normalised with product mass and surface based specific energy is determined from the results enabling a study of the grinding performance regardless of mill size, energy level or charge mass. Incremental breakage tests using the JKRBT indicate that the A×b values of the T-ore were 60% higher than C-ore, suggesting the T-ore is considerably softer. The fractional mass loss rate for the T-ore in the 0.8 m and 1.8 m mills started from 16 and 7 (1/kWh/m2) while for the C-ore it was 4 and 2 (1/kWh/m2). After 6 minutes the surface damage index in all tests tends towards steady state a constant value, an indication of steady state surface damage condition. It has been demonstrated that this methodology can be a useful basis for characterising superficial breakage behaviour of ores."

Jan 1, 2014

By Alan Bye, Nick Beaton, Wayne Stange, Emmy Manlapig, James Groutsch

"For over 50 years the JKMRC has applied a unique education-based research strategy to develop modelling and simulation tools that are "fit for purpose" for industrial application. These tools are widely used for the analysis and optimisation of mining and mineral processing systems. As the mining industry context evolves to deal with declining head grades, falling commodity prices, professional skill shortages, and an exponential growth in the volume of data, a re-evaluation of what "fit for purpose" means in the future is required. It is contended that future industry needs for simulation-based decision support requires tools and systems that incorporate: • Multi-component modelling, • Models of complex sensor behaviour, • Integration across the physical value-chain e.g. resource to market, • Financial analysis including risk and uncertainty assessment, • Enabling multi-criterion decision making (technical, financial and environmental), • Ore-body knowledge at multiple scales, • The use of fundamental numerical models to provide insight for the development of practically useful models, and • Decision support delivered through remote operations centres. JKMRC and CRC-ORE are collaborating to develop a next-generation simulation-based decision support system that assists in addressing these challenges. The Integrated Extraction Simulator (IES) combines many years of pragmatic and successful work integrated with modern technology trends - in particular the rapid move to cloud-based computing."

Jan 1, 2014

By Tom Leistner, Urs A. Peuker, Martin Rudolph

"It is well known, that for conventional froth flotation techniques the processing of ultrafine mineral particles is generally inefficient and results in rather low-grade concentrates and relatively high losses of valuable minerals. Therefore, the investigation of other possible methods, which can selectively separate such fine particle systems effectively, is of considerable interest. In this study, the application of two-liquid flotation, a flotation-related process using oil droplets instead of air bubbles, is investigated as a possible processing strategy for the separation of ultrafine particle systems. The investigation involves the testing of the two-liquid flotation technique as simple laboratory-scale batch trials and moreover, the up-scaling to a semi-continuous process by using a modified lab scale flotation column. Magnetite and quartz particles, with particle sizes below 10 µm respectively, as academic mineral mixture and iso-octane and water as the two immiscible liquid phases are chosen for the experiments. To manipulate the wettability of the magnetite particles as well as the interfacial tension of the oil/water interfaces, surface active reagents of fatty acid basis are introduced in the system. The selectivity of the process is characterized by determining the removal of magnetite particles from the aqueous suspension through selective accumulation at the oil/water interface or extraction into the oil phase, respectively. Operational parameters including pH of the aqueous suspension, additional electrolyte addition and surfactant type as well as dosage are varied in order to maximize the efficiency and stability of the process."

Jan 1, 2014

By Peter Ay, Bodo Müller, Jens Markowski, Manfred Kanthak, Florian Logsch

"Presently the global commodity situation for non ferrous-, precious- and rare metals is characterized by a strong increase in consumption and a simultaneous shortage of materials derived from primary sources. So the use of secondary raw materials gains is important due to economic and ecological reasons. Non Ferrous-, precious- and rare earth metals were detected in household waste (Municipal solid waste, MSW) for years. In MSW-treatments plants NF-metals are actually mostly separated from dried fractions. The separation of these metals is carried out with the aim of removing particles which disrupt further processing. A selective enrichment of individual non-ferrous metals has not been carried out previously. The separated fractions contain mixtures of Al, Cu, Zn, Pb, Sn, alloys, precious metals (e. g. Au, Ag, Pt) and rare metals (Ga, In, Nd etc.) along with considerable amounts of contaminations. The R&D project "NE-Rec" selectively processes the coarsely separated non-ferrous-metal-conglomerates increasing the concentration of targeted metals. Metals and metal mixtures are concentrated by sorting steps and the impurities are discharged from the process. Still contaminated precious metals are then subjected to a wet-chemical treatment. So metals can be specifically brought into solution or can be precipitated to separate unwanted components (inerts, polymers, foreign metals). Further the relevant metals will be concentrated by thermal-metallurgical processes. The technology, developed in the R&D project, enables identification, separation and processing of non-ferrous metals, precious metals and REM in household waste and transfers them into further processable individual fractions."

Jan 1, 2014

By Nani Pajunen, Kari Heiskanen

"Products filling our societal needs, like communication and transportation needs, are becoming more sophisticated and efficient. The cost has been an increased complexity of material combinations. The same trend is also seen in investment goods. As an example, different crusher types have almost doubled the power to weight ratio in a relatively short time while producing even higher crushing rations. This has been possible by high performance materials and advanced designs. Another example is new hybrid materials in prefabricated high-strength steel structures in construction with the aim to lighten the products and obtain energy savings in the use phase e.g. in transportation. This development in general has made the end of life phase obscure. Recycling is often understood as the first phase of the material cycle. This has been supported by the material centric point of view. When, say indium, has been collected and mechanically treated to a concentrated fraction, it is assumed as recycled. This is not the case. The same applies to special steel alloys where one tends to lose some of the alloying elements to slag or even into the gas phase in the melting and refining stage, not in the earlier steps of recycling. At present there is no clear understanding of recycling of hybrid materials and no clear willingness to create new functional recycling systems. As the EU directives and most of legislation worldwide are based on the material centric thinking and implemented even on total mass recovery basis there is neither legislative incentive nor very strong economic incentives to work out the problem. In our research, we focus on industrial design towards sustainability from a product centric point of view from product collection to final metallurgical steps. It is vital, in the design phase of product, to understand the effects of decisions on recyclability to a saleable raw material. Main goal of our work is to create the fortunate circumstances in supply chain - to pass the barriers and find the effective and fruitful drivers - for reasonable use of raw materials and recycling co-operation with industry. The boundary conditions in the work are extractive metallurgical performance and the economic viability of all the steps. It can be shown from our work that small design alterations may have a large impact on the recyclability. The earlier the decisions are made in the product life chain the more positive impact they will have. It can also be shown, that a strong processing and metallurgical industry is vital to any meaningful recycling of the modern EoL products. Finally, it is also question of the individuals and values: supply and demand. Are you ready to take up the gauntlet: demand recyclable products."

Jan 1, 2014

By D. Saramak

Investigations over the application of hybrid comminution circuits with the High-Pressure Grinding Rolls (HPGR), on the main comminution stage on the basis of the lime and cement industry, were presented in the paper. Two crushing circuits were investigated, the first HPGR-based and the other one, with conventional jaw crusher. The results presented in the article confirm that hybrid comminution circuits with the application of HPGR are innovative ones, and they assure achieving the technological and economic competitiveness in the mineral raw materials processing industry. They are much more favorable in terms of the final product fineness and capacity but insignificantly less effective about the unit energy consumption. Technological performance of conventional crushing circuit and HPGR-based one were also compared in lab scale. The circuit with HPGR application gives finer products both on crushing and grinding stages. The average particle size reduction obtained in HPGR-based circuit is as much as twice greater, comparing to the conventional crushing devices. Keywords: comminution, HPGR technology

Sep 1, 2012

By S. Banisi, A. R. Ghasemi, M. Maleki-Moghaddam

Direct observation of the charge shape and its motion in industrial mills are not possible, it is then customary to use transparent end, small-scale mills (i.e., model mills) to determine the charge trajectory directly by visualization methods. Because of a short length of the model mills, the end-wall effects could introduce a significant bias on the observed charge trajectories and shape. The shorter the mill, the stronger the bias. This could be due to some material bridging between the end walls. In this research, the end-wall effects were investigated by gradually increasing the model mill length and analysing the charge trajectory and shape variation at a given operating conditions (i.e., ball filling, mill speed, liner type). The unbiased mill length was assumed to be beyond the mill length where no significant change observed in the charge trajectory and shape. For all tests, the torque of the charge was also measured by a torque sensor. The special design of the model mill with the diameter of 100 cm made possible to increase the mill length in steps of 3.6 cm up to 21.6 cm. Four types of liners, five steel ball fillings (10, 15, 20, 25, 30% v/v) and three mill speeds (55, 70, 85% of critical speed) were tested. The ball sizes ranged from 4 to 12 mm. The results indicated that when the mill length was below 10.8 cm the end walls prevented the charge from free falling. This resulted in lower impact point angles and lower power draws compared with the case of no end-wall effects. When the same experiments were performed using an iron ore instead of balls with the same size range, the impact of end-wall effects was more pronounced. For an increase of 30% in the speed (from 55 to 85%), the torque due the change in the charge shape decreased by 41% (from 3.7 to 2.2 kgf.m) when mill filling was 30%. At the same operating conditions when steel balls used the torque decreased only by 19% (from 9 to 7.2 kgf.m). This was expected due to irregular shapes of the ore particles which facilitated bridging. Three-dimensional DEM simulations also resulted in the similar conclusions.

Jan 1, 2014

By Henrique Kahn, Daniel Uliana, Carina Ulsen, Guilherme Nery

"Gold has been a material in high demand since the dawn of humanity. After hundreds of years of exploitation, the increasingly search for gold occurs in lower grade deposits with greater extraction difficulty. Therefore, for maximum efficiency, deep knowledge of the characteristics of these minerals and their associations is crucial, which is acquired through an accurate and rigorous routine of process mineralogy and batch extraction tests. The industrial gold process extraction occurs by gravity concentration, sulphides flotation and cyanidation. For gravity concentration, it is fundamental to establish the proportion of free or coarse gold grains and its association to heavy minerals; regarding flotation, the most relevant data are the proportion of gold associated to sulphides and their liberation by the surface area; for cyanidation, it is crucial to evaluate gold accessibility and the kinetics of leaching. Thus, the characterization of gold associations and liberation is vital to establish the plant design, to optimize operating plants and to reduce gold losses. Our aim is the characterization of gold occurrence in low-grade Brazilian deposits with complex mineralogical assemblages to support processing flowchart definition and to predict metallurgical recoveries. Gold distribution in light and heavy minerals was evaluated by heavy liquid separation and the occurrence of gold in free or locked particles was carried out on heavy products by SEM-based automated image analysis using the MLA system. All the products of heavy liquid separation were cyanidated in head samples with different milling conditions to evaluate the reaction kinetics and maximum recovery."

Jan 1, 2014

By S. A. Bogidaev, M. Yu. Tiunov

"The paper describes the results of the flotation tests with complex rare metal ores from deposits in the Trans-Baikal Territory. Correlations between the quality of produced wolframite, hubnerite and mica concentrates with or without the presence of various alkaline modifiers are determined. Commonly, rare metal ores contain minerals of comparable value to main elements recovered in processing plants using gravitational methods. The paper describes the results of flotation recovery of valuable minerals – main and associated – from gravity tailings of deposits in the Trans-Baikal Territory. It was found that gravity tailings from the first deposit contained fine-grained wolframite, mica (muscovite, lepidolite etc.), feldspar; hubnerite, scheelite, beryl, fluorite, rubidium-containing muscovite from the second deposit, correspondingly. This paper presents the results of the stage flotation tests with the production of tungsten (wolframite, hubnerite), fluorite and mica concentrates from gravity tailings. Figure 1 demonstrates the flowsheet of tungsten ore minerals and mica stage flotation from gravity tailings of the first deposit.Wolframite can be floated using oleic acid with the presence of soda ash, a complexing collector (IM-50), under slightly alkaline conditions in combination with a nonpolar collector [1, 2, 3, 4]. The study included wolframite flotation using the combination of two alkaline modifiers. Flotation of wolframite was performed after pulp desliming, using tall oil saponified with soda ash. The recovery of wolframite in the concentrate of rougher flotation reached 80-85%; the concentrate contained up to 1% of tungsten oxide that can be upgraded to a saleable product using gravitational methods. This procedure was tested during flotation of wolframite, tantalite-columbite and pyrochlore, and provided high performance regardless of a season, at pulp temperatures of 8-10°C, though fattyacid collectors are significantly inefficient at such low temperatures due to low solubility, dispersion and increased collector consumption, consequently. The introduction of two alkaline modifiers in pulp appears to improve these characteristics.The first stage of the tests was focused on increase of iron-bearing tungsten ore minerals recovery from gravity tailings and stabilization of the cold pulp flotation process."

Jan 1, 2018

By Christopher Greet, Alfred Van den Bosch

"A range of media alloys with different chromium content has been developed for different milling applications. When selecting the grinding media alloy for a specific application, consideration must be given to the mineralogy of the ore as well as the water chemistry and mill operating conditions. The paper describes the influence of the microstructure of the alloy on the wear resistance and the influence of the chrome content on the pulp chemistry and downstream processing. It also provides information about the in-house tools which Magotteaux have developed to predict the media wear rate with different chromium content alloys and predict their flotation efficiencies that can be expected when the right alloy is selected for a particular application."

Jan 1, 2014

By Fiona Sofra, Briony C. Ruse, David B. Boger

"The sustainability of the mining industry must be addressed through improving tailings management. The use of thickened tailings and pastes stems from a paradigm shift towards designing tailings disposal sites to suit their surrounding environment, rather than manipulating the environment to accommodate the tailings. Thickened tailings and pastes usually exhibit non-Newtonian behaviour, so a thorough understanding of the rheological characteristics of the material is required in order to determine the disposal plant operating conditions.Full Cost Accounting techniques may be used to provide financial justification for the implementation of alternative tailings disposal techniques through the calculation of a disposal cost per tonne of tailings over the life of the facility. Improved disposal methods such as thickened tailings disposal involve additional initial capital expenditure but reduce environmental impacts. The cost savings associated with environmental impact mitigation are reflected in Full Cost Accounting outcomes.Rheological characterisation is significant as a design basis that may be analysed using Full Cost Accounting to justify the initial capital expenditure of dry disposal systems for improved environmental performance."

Jan 1, 2003

By Chuansheng Luo, Qiuyang Hong, Lili Zhang, Dongyun Liang

"The metallogenic rock of a sandstone-type Cu ore is arkose-quartzite as well as siltstone and the cement is composed of argillaceous minerals including sericite, chlorite, etc. and carbonate minerals including calcite, dolomite, etc. A detailed process mineralogy study on this complex copper ore was carried out using MLA combined with traditional research methods. According to the results, there are many types of Cu minerals including copper sulfideminerals, secondary copper sulfideminerals, copper oxideminerals, copper carbonate hydroxide minerals and copper silicate minerals in the ore. Based on the occurrence of Cu, the copper existing as copper sulfide minerals (bornite, chalcopyrite and chalcocite) and copper oxide mineral (malachite) which have a good floatability accounts for 49.28% while the copper (chrysocolla) hard to be recovered by flotation and the copper existing in the cement (sericite, chlorite, psilomelane and limonite) accounts for 48.65%, and the copper existing in the carbonate minerals (calcite and dolomite) accounts for 1.72%. The process mineralogy study indicates that the process "beneficiation combined with hydrometallurgy" should be applied due to the various occurrence of Cu. The abundance of calcite and dolomite is about 12%, so removing these acid-consuming minerals by floatation is an effective way to reduce the acid consumption in the hydrometallurgical process and the lowest Cu loss is 1.72%. So the process "floating copper minerals-floating calcium minerals (calcite and dolomite)-leaching copper from the tailings" is used in the pilot tests. The recovery of floating copper and leaching copper from tailings is 46% and 30% respectively, so the total recovery of copper is 76%. Compared with the original process "leaching copper from crude ore-floating copper from the residue", the total recovery reduces by 1% but the acid consumption of producing per ton of copper decreases from 37t to 12t. The new technology process has a great advantage."

Jan 1, 2014

"The business importance of water for mining companies is unequivocal as it may affect several aspects of mining projects ranging from the life-and-death license to operate to the imperative economic viability. It is thus no wonder that nearly all mining companies acknowledge water-related risks, issues and opportunities in their respective sustainability report. Somehow, this procedure has fostered the idea that water frugality could be the sustainable solution to several water-related issues. The regular exercise of water accounting should then follow as a key strategic requirement. Water accounting is defined as the application of a consistent and structured approach to identifying, measuring, recording and reporting information about water. However, several factors discussed herein have led to the fact that some water accounts are still produced using means (hardware and software) which undermatch the value actually associated with water. The resulting fuzziness about water usage could result in missed opportunities, suboptimal operations or even lead to environmental law violations. This paper subscribes to the distinctive perspective that, once underlying concepts and practical definitions have been standardized under a supported framework, such as the openly available Water Accounting Framework (WAF) published by the Minerals Council of Australia, most of the remaining water accounting issues may be boiled down to accuracy issues and, ultimately, to how much accuracy is valued by the stakeholders. Using the latest WAF document as a baseline for best practices of water accounting and, borrowing concepts from the fields of sensor network design in the process industries and best practices of metal accounting, this paper reviews some essential accuracy issues to be considered when designing or analyzing water accounting systems in mineral processing. The current paper also includes some elements for a promising attempt to include the value of information paradigm inside the water accounting best practices."

Jan 1, 2014

By Kazutoshi Haga, Atsushi Shibayama, Altansukh Batnasan

The objectives of this study were to propose a viable alternative method for recovery of precious metals such as gold (Au), silver (Ag) and palladium (Pd) from waste printed circuit boards (WPCBs) and to regenerate the spent lixiviant solution for reuse. The proposed method generally consists of several steps as follows: 1). iodine-iodide leaching for metals extraction; 2). separation and recovery of precious metals and metal impurities from a pregnant leach solution; 3). regeneration of the spent iodine-iodide solution/lixiviant. In this method, more than 99% of Au leaching was achieved in the iodine-iodide solution from the solid residue of WPCBs that was obtained via sequential processes including incineration at 800 ?C and high pressure oxidative leaching with a diluted sulfuric acid at 120 ?C, while the leaching of Ag and Pd was less than 1%, respectively. Besides Ca, Cu, Ni, Co and Zn as main metal impurities, leaching efficiency of other metals did not exceed 1%. The precious metals and base metals as metal impurities present in the pregnant leach solution were separated and recovered by precipitation using L-AA and NaOH solutions. About 99.8% Au, 81.7% Ag and 72.8% Pd were recovered from the pregnant solution at pH of 2 with the addition of 0.1 M L-AA as precipitating agent. The remained small amounts of precious metals and metal impurities were precipitated at pH 13 using 1 M NaOH. The spent lixiviant after sequential precipitation was regenerated in the presence of hydrogen peroxide, hydrochloric acid and potassium iodide. It was revealed that over 90% of gold could be extracted from the residue of WPCBs with the regenerated lixiviant solution.

Jan 1, 2018

By Vladimir Vigdergauz, Sergey Kondratiev

The paper reviews the existing criteria of the formation of particle-bubble aggregates during flotation. It is shown that predictions obtained by these criteria do not completely fit to the interaction between mineral particles and air bubbles. Experimental results of the studies into the influence exerted by molecular forms of collectors on the particle-bubble interaction are reported. Rate of dry spot expansion on the surface of pyrite with various combinations of chemically and physically adsorbed xanthate are examined. It is shown that molecular forms of collectors accelerate the rate of dry spot expansion on the mineral surface after the local rupture of the water film between particle and air bubble. The authors come to a conclusion that the molecular forms of collectors remove water from the interlayer between mineral particle and air bubble during their contact. Similarities of the proposed mechanism with the action of ion-molecular associates of fatty acids and amines are discussed. Reagents with high surface pressure and rate of spreading at the water-bubble interface are required for the effective interfacial dewatering. It is concluded that the value of surface pressure can serve as the criterion for efficiency of physically adsorbed reagents. The low surface pressure indicates weak collecting ability but high selectivity of the collector. Therefore, the presence of the molecular forms of collectors in the sorption layer is the necessary condition for formation of particle-bubble aggregates, and comparison of the surface tensions of collectors could be recommended as the estimation criterion of their flotation activity and selectivity.

Jan 1, 2014

By Chao Li, Kym Runge, Saeed Farrokhpay, Dee Bradshaw

"It is well known that froth phase has a controlling influence on the overall flotation performance. Froth recovery is expected to be affected by froth transportation behaviour. The latter has been represented by different volume balance and energy balance based models. In froth transportation models based on a volume balance, the froth phase is divided into different zones. The total froth residence time is the sum of the time spent in each zone and is dependent on the cell geometry, bubble burst rate and the position that bubbles enter into the froth phase. Alternatively, the froth transportation model based on an energy balance treats the froth phase as a block. In this model, froth height above the concentrate lip is being predicted by minimising the energy of the system which is dependent on the froth geometry, froth stability and froth rheology. The froth height can be used to calculate the froth efficiency of delivering mineralized bubbles from the pulp to the concentrate lip. This paper critically analyses the current models of froth transportation in flotation, and examines the limitations of these models. The importance of froth rheology, which is the resistance to the froth flow towards the discharging weir, in determining froth transportation, is also highlighted."

Jan 1, 2014

Calcium sulfate whiskers are considered to be a prosperous reinforced material in application due to their high mechanical properties. But the hydration occurs easily at moist atmosphere or in aqueous solution. The surface topographies of the calcium sulfate hemihydrate whiskers and the hydrates were analyzed by on-line observation and using XRD. The results indicated the transformation of the crystal type and shape of calcium sulfate hemihydrate whiskers and the reduction of whiskers? aspect ratio. The hydration process of the calcium sulfate hemihydrate whiskers and the effective parameters were further discussed based on FT-IR measurements. The conclusions were obtained that the hydration of calcium sulfate hemihydrate whiskers can be divided into the three phases, namely, initial hemihydration phase, dehydration phase, and coarsening, dissolving and the re-formation of calcium sulfate dehydrate crystal phase. In addition, it was found that in the hydration process of calcium sulfate hemihydrate whiskers the calcium sulfate dihydrate whiskers are formed at first and then converted into the calcium sulfate dihydrate with different crystal shapes, but in the hydration of gypsum hemihydrate the gypsum dihydrate is formed without transition products. The surface active site-calcium ion which has strong trend to react with H2O, the surface ?OH and the inner channels are considered to play important roles in the hydration process of calcium sulfate hemihydrate whiskers.

Jan 1, 2014

By V. A. Feofanov

Technogenic water of ore mining enterprises, nonferrous metals operations, the enterprises of electroplating and instrument making, containing copper in the form of those or other connections can serve as perspective sources on receiving the copper-bearing raw material. Extraction of copper from the given water also solves a problem of water treating from a toxic component that reduces environmental load at evacuation of water in an open basin. The method of case hardening allows extracting copper selectively with reception of a deposit with the content of copper up to 70%. Weakness of the method is its efficiency basically in acid reduction, and also its low degree of copper extraction. On the basis of case hardening the method of galvanic coagulation is devised. It is based on the work of a short-circuited galvanic cell of iron-coke at variable contact of coupled metals components among themselves, cleared by the oxygen of air. The following processes of galvanic coagulation are considered: ? Extraction of copper; ? Formation ferrites of copper; ? Copper sorption on just-aggregated oxide forms of iron. Establishing conditions for passing the given stages provides an opportunity of copper extraction from technogenic water at any value of ??, content of salt and concentration of copper with reception of a compact deposit from which it is possible to extract copper by the known ways of enrichment and metallurgy. Investigations on optimization and intensification of galvanic coagulation with the purpose of reception the maximum rich deposit on copper have shown that the average contents of copper in a solution of 100~200 mg/dm3 the contents of copper in a deposit is 6%~10% at extraction 85%~90%, depending on characteristics of treated technogenic water. Using methods of scanning microscopy it is determined structures, composition and mechanism of phase formation in investigated electro-chemical process. The second stage of galvanic coagulation increases a degree of copper extraction up to 98%~99% that allows returning the cleared waters in circulation for waste recycling or evacuation in an open basin. Nowadays the method of galvanic coagulation is the most acceptable for copper extraction from technogenic water both from the point of view of efficiency and instrument setting that allows applying the method in conditions of the working enterprises.

Jan 1, 2014

By Cristian Melipichun, Leopoldo Gutierrez

The effect of the presence of fine particles of kaolinite and montmorillonite on the induction time for attachment of bubbles to particles of a copper concentrate rich in chalcopyrite was evaluated in this study. The results obtained from induction time measurements were correlated with data of concentrate recovery achieved from micro-flotation experiments. The effect of the presence of fine clays on the stability of air-water foams was also studied through measurements of the foam volume generated in a glass column under different conditions of air flowrate and MIBC concentrations. The experimental results showed that induction time values increased under the presence of fine clays. These data agreed with results obtained from micro-flotation experiments that showed that copper concentrate recovery decreased when clay particles were added. Although a complete explanation for these results is not available, the fact that experimental observations indicated that fine clay particles tend to adsorb on gas bubbles, suggests that the interactions between fine phyllosilicate particles and air bubbles have to be taken into account when studying the effect of clays on froth flotation. Foamability tests showed that the presence of fine clay particles increased the foam volumes only at high additions of clays and low dosages of MIBC. The results obtained at higher dosages of MIBC showed that the foam volumes decreased with the addition of clays under all the experimental conditions tested.

Jan 1, 2014

By Yu. Gurevich, M. Teremova, I. Prokopev, A. Razvjaznaya, N. Algebraistova

"The objective of this work is the scientific justification and development of efficient and environmentally-friendly method of bulk concentrate preparation for selection with application of microbiological practices. This research suggests to apply Pseudomonas Japonica bacterial culture to the bulk concentrate before the selection circuit in order to clear the surface of sulphides from the xanthate skin. It is also suggested to apply bacterial consortium Ochrobactrum ?nthropi and Pseudomonas aeruginosa JCM 5962 for desorption of diesel residual concentrations. High-efficient and environmentally friendly method of copper-molybdene and lead-zinc bulk concentrate selection was developed based on theoretical and experimental research work with application of microbiological practices. In comparison with conventional methods (steaming, sodium sulphide washing) the above suggested bio-technological method of bulk concentrate preparation before selection cycle will allow to reduce material and power expenditures, and it is also environmentally friendly. INTRODUCTION High-efficient selection of sulphide bulk concentrate is gained exclusively after collecting agent is removed from mineral surface. Therefore, the problem of bulk concentrate preparing before the selection cycle is acute, since the further technological parameters of the subsequent separation depends on the effectiveness of pulp preparation. Existing traditional ways of bulk concentrate preparation. such as washing or steaming, are characterized by high energy and material costs in industrial conditions [1,2]. The microbiological treatment before separation of the bulk concentrate into different kind of concentrates appear one of perspective processes for treatment of bulk concentrates [3,4]. At the present time, the world practice of processing mineral raw materials demonstrates the wide application of technologies using microorganisms: bacterial leaching and oxidation, purification of industrial wastewater. This is due to the fact that biotechnological methods are environmentally safe, low-cost, and suitable for refining complex ores and raw materials of industrial origin."

Jan 1, 2018