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By Andrzej Luszczkiewicz, Tomasz Chmielewski, Jan Drzymala, Andrzej Konieczny, Rafal Kaleta

Properties of the sedimentary Polish copper ore mined from the Legnica-Glogow Copper Basin (SW Poland) by KGHM Polish Copper S.A. were presented and currently used beneficiation technologies were described. Due to a unique lithological layered structure of the polymetallic deposit and existing mining system, the ore currently processed in the three KGHM concentrators is very complex with variable content of the carbonate, sandstone and shale fractions. The mined copper ore contains from 0.8 to 1.8 % Cu and Ag, Pb, Zn, Ni, Co, V and Mo as accompanying metals. The paper presents difficulties in upgrading the LGOM ore and selected possible solutions and development concepts of its processing. The first one is a chemical treatment with controlled amount of sulfuric acid of special product of flotation such as for instance middlings. The acid treatment leads to increased liberation of copper minerals and better further processing. Another concept is atmospheric leaching in oxygenated sulfuric acid and ferric ions solution as the major unit operation applied to selected low grade final flotation concentrates or flotation by-products. The third approach, based on copper ore pre-flotation with a frother to partially remove Corg, is also considered.

Jan 1, 2014

By Muammer Kaya, Sait Kursunoglu

"Energy is the major concern for society. It is expected that developing country economies and populations will grow and consume more energy. Interest in nuclear power is rising, while the world looks for non-depletable energy source that will not contribute to global warming. However, it still has concerns of nuclear proliferation, radioactive waste and safety. It is necessary to overcome these concerns if nuclear energy is expanded to developing countries. Thorium (Th) utilization as nuclear fuel will be an opening key of these difficulties because Th produces less Plutonium (Pu) and less radioactive waste with enhanced safety. Research into the use of Th as a nuclear fuel has been taking place over forty years, through with much less intensity than that for uranium (U) or U-Pu fuels. Nuclear industry is currently using only 0.7% of the available energy from mined U. With huge resources of Th and relatively little U, Turkey has made utilization of Th for large-scale energy production a major goal in its nuclear power programme. Thorium fuel is plentiful and inexpensive. Energy is major concern for developing Turkish society. Turkey, today exports more than 70% of its energy as fossil fuels. In the last 50 years, Turks are skeptical, anxious and indecisive about having nuclear energy for electricity production. In the last 10 years, Thorium is brought into Turkish government’s attention and national discussion as a new, safe, clean, affordable, CO2-free, alternative, strategic and domestic nuclear energy fuel. Turkey recently contacted four VVER-1200 type Russian Nuclear Power Reactors using U as a fuel in Akkuyu (Rosatom) and another four units will be established in Sinop in the next decade by Japan (Mitsubishi-Westinghouse). Turkish nuclear programme must envisage use of domestic Th as a fertile material. This paper briefly reviews the developments of Th-fuel cycle for nuclear energy from global and Turkish perspectives. Previous Th reserve development and recovery studies from Turkish bastnasite ore are summarized in this paper."

Jan 1, 2014

By F. O. Milovich, V. A. Ignatkina, L. A. Samatova, E. D. Shepeta

"The aim of the research was to increase technological parameters of the flotation of finely disseminated scheelitecarbonate ore using selective reagent regime.In the studies the monomineral fractions of scheelite and calcite; samples of the scheelite-carbonate ore of the Primorsky deposit with the range of the carbonate module 3-65 were used. A carbonate module of ore is the ratio an initial assay of calcite to an initial assay of scheelite. Sodium oleate, iso-decyl alcohol, water glass, calcium chloride, soda or sodium hydroxide as flotation reagents were used. The flotation method in the Hallimond tube and in a mechanical cell, an adsorption method for study the kinetics of adsorption of oleate and isodecyl alcohol and its combinations on scheelite and calcite, IR spectroscopy including ATR to study the composition of surfacecompounds were applied. Selective reagent regime may include two ways - a combination of collectors or a modification of depressants of calcite and other gangue minerals. On one hand the combination of sodium oleate and higher fatty iso-alcohols of fractions C12-C16 in the rough scheelite flotation to reduce the flotation activity of calcite has been studied. On the other hand depression of calcite flotation by calcium chloride with water glass into rough flotation was used; modified the steaming cycle by Petrov's method applying change the concentration of water glass and other. Fatty iso-alcohols can adsorb on the surface of the calcite that reducing the adsorption of sodium oleate and floatability of calcite has been fallen. Their co-adsorbing with oleat on the scheelite surface were support the hydrophobization and flocculation of slime particles of scheelite. Flocculation of the particles of scheelite leads to increased up 3 times of the recovery of scheelite from the slime class, and calcite change up only 1.4-1.1 times it’s recovery.The growth of the carbonate module more than 11 is decreased the assay of WO3 in the scheelite concentrate of selection cycle."

Jan 1, 2018

By B. McFadzean, K. Moller

"The mechanism whereby thiol collectors adsorb onto a mineral surface has been widely studied. Most of these studies examine the mineral surface at equilibrium state and, often, well above monolayer coverage. However, the formation of species at the mineral surface is a complex process that is both kinetically and thermodynamically controlled. In a typical industrial application, the dosage of collector will be around monolayer level. This study uses isothermal titration microcalorimetry to measure the heat evolved during the reaction of sodium ethyl xanthate (SEX) and sodium isobutyl dithiocarbamate (SIBDTC) and their mixtures with galena and chalcopyrite. The sensitivity of the instrument allows heats of reaction of sub-monolayer quantities of thiol collector to be measured.The study found that both the magnitude and kinetics of the reaction between a collector and a mineral surface was dependent on the type of mineral and the type of collector. Proposals are made for the reactions based on literature and the evidence from this investigation. It was found that when collectors were reacted with mixtures of galena and chalcopyrite, that the magnitude of the reaction was lower compared to that measured for the pure minerals alone. This may be due to galvanic interactions between the minerals, resulting in a passivating effect on one or both of the minerals."

Jan 1, 2014

By Markus Dammers, Christopher Robben, Hermann Wotruba, Christian Schropp

"In most underground mining processes the entire extracted ore is transported from underground workings to surface processing plants for separation of valuable minerals and gangue material. Most of the transported material consists of barren rock with negligible metal content, especially for low grade deposits, such as in the copper or gold metal ore mining. Increasing mining depths result in higher costs for transportation and hoisting. Therefore, rejecting waste rock as soon as possible from the material stream gains importance. The concept of resource to product integration in the form of earliest waste rejection in combination with subsequent backfilling follows the philosophy of ‚leaving waste underground?. Implementing mineral processing underground can lead to less required mass movement to surface, hence reducing transportation and hoisting costs. At the same time, rejected waste can be used as backfill to increase extraction rates by reducing pillar volumes. In the mill, a stable high grade feed leads to decreased specific operating and investment costs as well as increased productivity and recovery. These effects as a whole have a large potential to reduce cut-off grades so that resources can be turned into reserves. Within the I²Mine (Innovative Technologies and Concepts for the Intelligent Deep Mine of the Future) project of the European FP7, investigations are carried out by the Unit of Mineral Processing of RWTH Aachen University, the Institute of Mining Engineering I and TOMRA Sorting Solutions | Mining. One aim of the cooperation is to develop new concepts for a comprehensive integration of near-to-face processing in combination with backfill into the overall underground mining process. Effects on up-, down- and side-streams are investigated to prove the potential of resource to product integration in comparison to common underground mining systems and processing methods."

Jan 1, 2014

By Leena Vesa, Antti Remes

Design of thickeners is based on laboratory test work, characterizing the material and determining the optimal reagents, dosages and settling regimes. Several methods for dimensioning plant scale equipment exist. Kynch and Talmage-Fitch design procedures has been applied widely for a long time. Nowadays, besides them, a dynamic laboratory test work is applied for design of high rate thickeners. In that the laboratory unit is operated with known solids load per area, feed and flocculation conditions and with raking of the underflow. All these test methods afford useful data for setting up and calibrating a dynamic simulation model of a plant scale thickener. This paper presents a flocculation kinetics based dynamic thickener simulation model and a procedure to calibrate the model parameters. With the model, the underflow stream composition can be simulated over time as a function of the thickener operating parameters, which are: the feed rate and composition, underflow pumping rate, flocculant dosage and dilution of the feed. In addition, the model incorporates calculation of the slurry bed level, the cone pressure, the yield stress and the rake torque. Such a dynamic modeling scheme enables setting up simulation aided operator trainings and developing and testing of advanced control strategies, for example. The unit model can be integrated as a part of concentrator-wide flow sheet simulation model as well. Here, calibration of the kinetic flocculation model based on a laboratory test case data and further the operation of a simulated plant scale thickener are presented.

Jan 1, 2014

By P. Banerjee, P. Dash, S. Sriramoju, A. Suresh, R. Lingam, T. Ray

"One single property that influences the quality and market value of coal to the maximum extent is the ash content. The lower the coal ash higher is the energy utilization and potential for different applications. Even though Indian coal washeries aspire to produce coal with low ash, the intimate distribution pattern of ash bearing minerals in the coal matrix becomes the real bottleneck, as it brings down the clean coal yield to the impractical value. Because of this fact, most of the Indian washeries are operated to produce coal with 14-15% ash content at the yield of around 40%. In this context, with an objective to produce low ash coal at higher yield, a novel chemical beneficiation route has been explored to demineralize the high ash containing Indian coals. In this present work, the production of low ash clean coal from high ash Indian coals using chemical leaching process has been studied at pilot plant level. The leaching process parameters such as reaction temperature, reagent concentration, reaction time, coal-liquid ratio and agitator speed have been optimized for the flotation tailings sample from a captive washery of Tata Steel. The results obtained show that 67% demineralization could be achieved in a single stage of leaching process with a product yield of more than 65%. For further demineralization, multistage leaching was carried out and the results showed that 75-85% demineralization could be achieved with significant reduction in alumina to silica ratio. Additionally, the phosphorus content is also significantly reduced from 0.20 % to 0.022 %. Further, it is interesting to note that there is no increment of sodium content in the product coal after chemical treatment."

Jan 1, 2014

By Igor P. Solozhenkin, Peter M. Solozhenkin, Sanda Krausz

"In this work, authors will show the efficiency of computer technology and chemical programs at studying collectors for flotation of minerals of elements of platinum group (EPG). Clusters various minerals EPG (flotation reagents) are created, named us clusters minerals (reagents) as their structure corresponds to the chemical formula, and the distance between separate atoms corresponds to the known tabulated data. By molecular modeling are investigated clusters sperrylite PtAs2, stumpfilyte PtSb, sadberryte PdSb, sobolevskite PdBi, palladoarsenyte Pd2As, paolovyte Pd2Sn, rustenburgyte (Pt3Sn, Pt6Sn2) and their computer parameters (absolute rigidity, electronegativity, transfer factors of carry, charges of the atoms) are determined. Tellurides of palladium (IV, II) merenskyite PdTl2 and kotulskyte PdTe and platinum clusters are investigated: PtFe4, Pt3Fe, PtFe (Pt2Fe2), Pt2Fe (Cu) Ni. The technique of attachment of the collector (composites) to cluster atoms EPG is offered. For the first time, it is established that at linkage of flotation collectors on monodentate, bidentate and bridged to circuits with atoms clusters the minerals containing atoms As, Sb, Bi, Pb, Sn, reaction of connection with change of a degree of oxidation of these atoms and occurrence of a proton operates. It is executed virtual skirling organic compounds connections by the developed criteria from accessible libraries of a database. The principle of an estimation of interaction energy for flotation reagents with mineral clusters is offered. It is developed the prognosis of collector activity evaluation (P?AE) and his values for candidates in collectors for flotation of minerals EPG are calculated. For flotation of ores containing Pt and Pd minerals, a number of reagents, including compounds on basis P (III), for innovational technology of Pt, Pd mineral flotation are recommended. Key words: flotation, minerals, flotation reagents on the basis of phosphorus (III), molecular modelling, chemical programs, program ????? , electronic energy."

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 Henrique Kahn, Daniel Uliana, Juliana Antoniassi, Viviane Shimizu

"Mineral exploration and geometallurgy require a large number of samples for physical, chemical and mineralogical assays. The combination of all these data and their spatial distribution define the ore variability. This is important in exploration programs and crucial in feasibility studies as well as at the production operation level. Ore mineralogical composition and its associations, characterizing the geological formation and mineralization, are the main keys to define the ore domains and its variability, which can be quickly assessed by cluster analysis and by modern automated mineralogy tools. One hundred and ten copper ore samples from Sossego mine, in Brazil were compared and classified by X-ray diffraction cluster analysis based on the position and the intensity of the diffracted peaks. Initially four ore types were categorized based on content of major minerals: quartz, feldspar, amphibole, iron oxides, mica and chlorite. Results showed a strong correlation between the grouping and the samples location in Sequeirinho and Sossego orebodies, with a straight link to types/intensities of hydrothermal alteration prevailing in each body, which reflects the mineralogical composition and thus the X-ray patterns. Samples from four recognized ore types were submitted to detailed automated mineralogical studies by electron beam image analysis and differ strongly from each other regarding their chemical and mineralogical compositions and relevant parameters for mineral processing. Chalcopyrite is essentially the only valuable mineral, occurring both as submillimetric grains included in other minerals and as larger crystals. Except for pyrite, other sulfide minerals occur as traces. Chalcopyrite liberation curves indicate that samples from Sossego have higher liberation degree than those from Sequeirinho. The proposed method proved to be very efficient and accurate to classify a large number of samples within a short time frame, allowing the distinction of the ore types regarding their mineralogical composition as well as the mineral processing parameters."

Jan 1, 2014

By Yizhong Yuan, Dao Li, Nannan Xue, Tao Liu, Yimin Zhang

A new multi-stage counter-current circulation leaching process for extracting vanadium from stone coal was proposed, and the main factors on multi-stage counter-current circulation acid leaching process were investigated. The results show that the vanadium recovery could reach 86% under the conditions of sulfuric acid concentration of 4 M, liquid to solid ratio of 2 mL/g, temperature of 95 °C, reaction time of 60 min, mean particle size of 125 µm and circulation acid leaching stage of three. The losses of vanadium in acid leaching solution appeared during the four-stage acid leaching process. The strong adsorption performance of new formed KAl(SO4)2(H2O)12 crystal was main reason.

Jan 1, 2014

By Stephen Gay, Dewetia Latti

"When improving a plant a mineral processing engineer would like to know the mineral composition distribution. In order to assess this distribution in particles, as compared to the corresponding distribution in particle sections, a procedure needs to be applied to the observed particle sections. Such a procedure is called a stereological correction. There exists many stereological correction procedures, but one group of such procedures is based on using those stereological equations that do not require making assumptions regarding particle shape or texture.In particular Davy derived an equation to estimate the covariance of mineral composition distributions for particles from both particle sections and linear intercepts. Furthermore, this covariance can also be used to measure the variance of the composition distribution of each mineral.This paper shall present results verifying this equation. The experimental method was based on obtaining particle information from serially-sectioned particles. Particle samples selected for serial sectioning displayed a range of natural textures including liberated, binary and composite particles. The exposed surface of the polished sections were analysed using QEM*SEM. This procedure was repeated until all of the grains have been polished away. The covariance of mineral distributions were calculated from the serial sections and compared with that calculated using Davy’s equation."

Jan 1, 2003

By Gábor Mucsi, József Faitli, Imre Gombköto, Sanjay Kumar, Zoltán Molnár, Balázs Ráczkevi, Ádám Rácz

"Generally, fly ash particles are very fine (< 100 ?m), mainly spherical and glassy materials form an outer shell on it. This paper deals with the laboratory investigation of ground fly ash based geopolymer. This material can be applied in many fields, mainly in the construction industry, e.g. non-structural elements, concrete, pavements and products, containment and immobilization of toxic, hazardous and radioactive wastes, advanced structural tooling and refractory ceramics, and fire resistant composites used in buildings, etc. The preparation of fly ash using high energy density milling is presented. Systematic experimental series were carried out in order to optimize the preparation process. The particle size distribution (LPSA) and structure of fly ash (FTIR) and the uniaxial compressive strength ,the permeability and structure of geopolymer product, furthermore the rheology of geopolymer paste were investigated. The product properties were studied as a function of the fly ash fineness. As a result of the investigation the relationship between the grinding circumstances, the ground material properties and the geopolymer characteristics was identified. It was found that the above mentioned physical properties of the geopolymer strongly depend on the grinding process."

Jan 1, 2014

By Joseph Kelly, Christopher Kelsey

This revolutionary super-fine crusher has the unique capacity to generate fine and ultra-fine products from single stage reductions of coarse or fine mineral feeds. The crusher consists of a rotating compression chamber and an internal gyrating mandrel. The axis of rotation of the shell is displaced relative to the axis of the vertically mounted mandrel. The inner surface of the compression chamber is machined as double cone frustums at an angle equal to the displacement angle. Crusher feed is accelerated into a compacted particle bed, which lines the inside of the compression chamber. The depth of the compacted bed progressively increases until the mandrel is engaged. The mandrel is then free to rotate with the compression chamber. Continued feeding increases power draw and triggers the counter rotating mandrel gyration drive. The gyrating mandrel delivers multiple compressions at high pressure to the rotating particle bed. High concentrations of energy are harnessed within a small active volume over short retention times. The combination of extraordinarily high power intensity and extreme compressive force results in primary compressive fracture and induced secondary tensile failure. The axially displaced rotation of the compression chamber effectively distributes the breakage forces throughout the particle bed. This paper covers open circuit, pilot trials on magnetite, perlite, garnet, marble and a copper/pyrite concentrate. Particular emphasis is placed on the extraordinary results achieved with trials on zircon and highly refractory fly ash. The extreme duties were deliberately chosen to demonstrate the crusher’s application scope and potential to impact capital operating and maintenance costs as the technology matures. Super-fine crushing, once considered impracticable has the potential to offer compelling options for the generation of ultra-fine products.

Jan 1, 2014

By T. Kalliomäki, B. P. Wilson, M. Lundström, J. Aromaa

"The diffusion rate of cupric ions and limiting current density are important factors that determine the rate of copper mass transport in electrolytes proximal to the electrodes used in electrorefining. As a result, diffusion can critically affect both the rate and morphology of cathodic copper deposition thus it is crucial that it be optimized to improve production. The diffusion coefficient of cupric ion (DCu(II)) in copper electrolytes has been previously researched but the values detailed in the literature show significant variations and moreover arsenic - a common impurity - is generally excluded. Furthermore, in previous studies the models have only been validated with model solutions rather than real industrial electrolytes. In this study, the limiting current density and diffusion coefficient of cupric ion were defined for synthetic electrolytes containing copper (40–60 g/dm3), nickel (0–20 g/dm3), sulfuric acid (130–220 g/dm3) and arsenic (0–45 g/dm3). The cathodic limiting current densities were measured at three temperatures (50, 60, 70 °C) with linear sweep voltammetry using the rotating disc electrode (RDE) as the cathode. By utilizing the limiting current density, models for the DCu(II) were constructed using Levich equation. The validity of the DCu(II) model for technical use was confirmed through their application to industrial electrorefining electrolytes with known element concentrations. Consequently, this study provides improved models for limiting current density and diffusion coefficient of cupric ion that can be utilized for industrial process optimization.INTRODUCTION For an efficient copper electrolysis process, the mass transport of copper ions has to be effective. The main mass transport types of copper ions in copper electrorefining are diffusion and convection while the effect of migration is negligible. In order to maintain good mass transport, it is beneficial to keep both diffusion and convection high to maximize the limiting current density (jlim) (Bard and Faulkner, 2001). jlim is the highest current density that can flow in the cell, thus by maximizing jlim the deposition time can be minimized and the good quality of cathodic copper can be ensured. Thus, it is important to research possibilities that increase and optimize diffusion since slow diffusion in the electrolyte limits the rate of the process (Levich, 1947; Moats et al., 2000; Subbaiah and Das, 1989)."

Jan 1, 2018

By Frank van der Meer, Lea Quincke

"High Pressure Grinding is applied to achieve size reduction of the particles by inter-particle breakage and to generate micro-cracks in the product particles as a contributing factor in e.g. leaching or mineral liberation. As alternative to classification, a closed circuit operation for HPGR can be established by product recycling, where a proportion of the coarser edge material and parts of the center material are split-off to be recirculated to achieve a finer final (center) discharge product for subsequent processing steps as ball mill grinding or beneficiation. As a result of the product recycling, the content of fines in the feed material increases and may affect the grinding efficiency in terms of production of fines and the generation of micro-cracks in the particles. In the scope of this paper, the effects of the proportion of fines in HPGR feed on grinding efficiency and micro-crack generation were evaluated. Grinding tests were executed with different feed size distributions, from a fines-void situation (truncated feed) to a fines-abundant situation (high product recycle). The evaluation of grinding efficiency and generation of micro-cracks was done by particle size analysis, Bond Work Index tests, impact tests on HPGR feed and products, and X-ray computed tomography of single product particles. This publication summarizes the main aspects of the outcome of these investigations."

Jan 1, 2014

By Sanja Miskovic, Manjunath Basavarajappa

Numerical investigation of fluid flow characteristics and mixing efficiency of different impeller designs, based on the mixing characteristics of a passive scalar/tracer, is conducted using CFD for lab scale flotation cells of diameter D and height H equal to 300 mm. Fine computational mesh containing close to 1.6 million cells is used to obtain fully resolved steady state flow field close to the impeller. Unsteady scalar mixing simulations are performed on a relative coarse grid consisting of approximately 450,000 cells. Based on detailed numerical simulations, flows are fully characterized for four impeller designs at two off-bottom clearances C of 50 and 25 mm (D/6 and D/12). Passive scalar is injected from the cell bottom and the time required to attain uniform concentration distribution inside the cell volume is taken as the mixing time by monitoring scalar concentration at four discrete locations. The effect of varying agitation speed and off-bottom clearance on mean flow characteristics is also investigated. The scalar mixing results reveal regions of low mixing efficiency and are used to understand mixing process in greater detail. Through the previous research work, it was found that the main flow pattern undergoes transition from double-loop to single-loop configuration with decrease in off-bottom clearance below a certain critical height for stirred tanks using flotation impellers in the absence of stator. The inclusion of stator is found to alter the mean flow behaviour by preventing the jet from transitioning to axial type flow for lower clearance. Power numbers for different impeller designs are calculated based on the torque generated on impeller blades, and also from the total turbulent kinetic energy dissipation in the overall fluid volume. Power number is found to exhibit a significant dependence on off-bottom clearance based on the CFD results.

Jan 1, 2014

By Tsvetan Damyanov, Nikolay Hristov, Evgeni Kostadinov, Lubomir Kuzev

"The process of grinding in drum mills is directly dependent on the dynamic forces occuring in the free movement of the grinding bodies in the volume. The subject of discussion are the potential impacts between grinding bodies having different shape and equal weight in a drum mill that has a diameter of 1200 mm. The study utilised ball grinding bodies having a diameter of 120 mm and tetraballpebs having a conditional diameter of 120 mm. The study was carried out using the Solid Works Simulation software. The following cases were examined: • Impact between two identical grinding bodies; • Impact between a grinding body and the shell surface. The study provided numerical values for impact force, kinetic energy of impact, linear speed of impact, linear displacment of the center of gravity and duration of impact deformation. The impact force of the balls is approximately 179000 N. The impact force of the tetraballpebs with typical vertices, edges and spherical surfaces depending on the area of impact is 177000 to 185000 N. Upon impact between two spherical surfaces of tetraballpebs, the contact area is 263.55 mm2, which is more than twice the contact area upon impact between two balls, which is 114.39 mm2. This determines better conditions for the transmission of kinetic energy by reducing opportunities for overgrinding."

Jan 1, 2014

By Érica Linhares, Anderson Silveira Lopes, Aline Costa

In the production units of ferromanganese alloys wastewater are generated. They mainly arise from gutters of drainage water from warehouse of raw material (manganese ore, reducing agents and other), product and slag. This wastewater, in general, may contain particles that will suffer difficulty to naturally decant, giving the water turbidity and color characteristics. Thus, this study aims to characterize the effluent, the treated water and the sludge from the sedimentation tank from the one main Brazilian plant. The investigated characteristics were: turbidity, total solids (TS), suspended solids (SS), dissolved solids (DS), pH, Eh, COD (chemical oxygen demand), residue classification and chemical analysis by ICP - OES. The turbidity before treatment was 417 NTU and after passing through the tank, 44 NTU, a figure slightly higher than the emission standards for Class 1 regulated by the Brazilian environmental legislation in force. The values for TS, SS and DS of the effluent were 225, 114.3 and 110 mg/L, respectively. For the treated water the values were 93, 48.3 and 45 mg/L for TS, SS and DS, respectively. The sedimentation process was able to reduce by 21 % of the COD. In the test of loss on ignition (LOI) from the tank bottom sludge were observed losses of 29.35 %, while the volatile analysis found 20.70 % of volatiles in the sample. It was determined that the concentrations of Al, Fe, Mn and S are, respectively, 0.1875 mg.L-1, 0.3071 mg.L-1, 0,789 mg l-1 and 0.00828 mg.L-1, values above the maximum allowed by law. Based on the analysis of X-ray diffraction, the identified minerals in the sludge were quartz, muscovite, kaolinite, calcite and albite.

Jan 1, 2014

By P. Huang

Chitosan was tested as a depressant in the differential flotation separation of chalcopyrite and galena. The micro-flotation results showed that chitosan selectively depressed chalcopyrite while galena was floated by potassium ethyl xanthate in acidic solutions. With the addition of 0.67 mg/L chitosan (CT) in the slurry of chalcopyrite-galena mixtures at pH 4, the recovery of galena was 95% while that of chalcopyrite was 30%, indicating that chitosan could potentially be used in differential Cu-Pb sulfide separation. Furthermore, the study of chitosan with either low (LCT) or high molecular weight (HCT) in the differential flotation indicated that better separation was achieved by the chitosan with lower molecular weight (LCT). ToF-SIMS was employed to study the distribution of CT on the surface of chalcopyrite-galena mixtures by ion mass spectra analysis and surface imaging, which showed that CT adsorbed heavily on chalcopyrite but barely adsorbed on galena. The positive ion ToF-SIMS spectra provided information on the surface composition of chalcopyrite-galena mixtures after CT treatment. It appears that the selective adsorption of CT on chalcopyrite was originated from the strong interaction between NH3+ and Cu. Keywords: differential flotation, micro-flotation

Sep 1, 2012