Polymetallic Sulfide Ore Research Articles

Selective flotation of galena using a novel collector S-benzyl-N-ethoxycarbonyl thiocarbamate: An experimental and theoretical investigation

A novel collector S-benzyl-N-ethoxycarbonyl thiocarbamate (BET) was used for selectively recovering galena from a polymetallic sulfide ore, and its flotation performance, structure-property relation and adsorption mechanism to galena were investigated. The raw ore flotation experiment demonstrated that compared with two conventional collectors sodium diethyl dithiocarbamate (SDD) and ammonium dibutyl dithiophosphate (ADD), BET displayed superior flotation performance to galena. Pure mineral flotation and adsorption tests also illustrated that among the three collectors BET possessed the strongest collecting ability and the best selectivity toward galena. The structure-property relation study based on density functional theory (DFT) calculation supported the above conclusion. The adsorption mechanism analysis through DFT calculation indicated that BET was chemisorbed on galena surface via formation of normal covalent bond between carbonyl S atom and Pb atom and back donation covalent bond between carbonyl O atom and Pb atom, which was verified by the result of Fourier Transform Infrared (FTIR) spectra analysis. This new collector exhibits not only strong collecting ability but also good selectivity to galena, and therefore it has wide industrial application prospect.

SIMULATION OF CONTROL SYSTEM OF THE CHEMICAL-TECHNOLOGICAL PROCESSES

In this work is consider study and analysis of dynamic system for simulation of the technological process under uncertainty and complexity. To study and simulate a complicated technology process we carry out for consideration the technology of the process of roasting in fluidized bed furnaces of polymetallic sulphide ores. The choice is justified by the fact that, operation line producing of polymetallic sulphide ores represents a complex process, is characterized by a big number of transient processes, presence of process variables and deviations from technical regimes. To study process characteristics of any system functioning by means of mathematical methods the process should be formalized. This means, that adequate mathematical model needs to be developed. The choice of mathematical model depends a lot upon the features of the object and its controllability as well as of technological scheme and complexity of processes. Chemical engineering processes are complicated physical and chemical systems. Substance flows, which are part of these systems, are, as a rule, multicomponent. Therefore, for the purpose of study and qualitative control over chemical-engineering processes it is essential to apply the method of mathematic simulation, based on system analysis strategy, analysis of its structure, mathematical formulation development and evaluation of unknown parameters. Controllability means that such system attribute as having control actions, which make it possible to transfer the system from a pre-set initial state to the required condition during finite quantum of time. Therefore, the developed mathematical model of the process or control object should be controllable and stability.

ТРАНСФОРМАЦӀЯ ПРИРОДИ ПРОВӀДНОСТӀ ВИСОКОПРОВӀДНИХ ХАЛЬКОГЕНӀДНИХ РОЗПЛАВӀВ В БӀК ЇХ ЕЛЕКТРОЛӀТИЧНОЇ ЗДАТНОСТӀ

Ibe aim of this work is to study the nature of the conductivity of melts of iron chalcogenides (Fe-Se, Fe-Te, FeS-Na2S) and the conditions of its possible transformation in order to bring the high-conductivity melt to a state suitable for electrolytic decomposition into metal and chalcogen. To solve this problem, a set of methods was used - electrical conductivity (ж), thermo-EMF (a), polarization characteristics (І-V) and electrolysis (n). ж of high-conductivity melts was investigated by the four-probe method on a direct current in a quartz U-shaped cell of capillary type with graphite electrodes and molybdenum current leads in the direct current mode. The systematic error due to the accuracy class of the devices is 1%; random - does not exceed 1%. Low ж melts were studied by the two-probe AC method. Due to the high chemical aggressiveness of FeS-Na2S melts, a measuring cell with an alundum capillary was developed. Random error when measuring ж two-probe method on alternating current is 3%, systematic - is within 2%. Thermo-EMF was measured by the differential method with respect to tungsten probes. The temperature difference between the probes was recorded by a differential thermocouple. Systematic error in measuring thermo-EMF was 2%, random - 1.5%. Polarization characteristics were removed by the method of direct current in a simple cell without separation of electrode spaces. In cells of this type in an argon medium over the melt and experiments on electrolysis were performed. It is established that all samples are characterized by significant values of electrical conductivity (of the order of thousands of Sm/cm) and its negative temperature coefficients; the absolute thermo-EMF of all samples is units of цУ/deg. Melts are qualified as electron-ion (polyfunctional) conductors with a predominant metallic contribution to the conductivity. The introduction of Na2S into the FeS melt leads to a decrease in electrical conductivity and the transformation of its temperature dependence to the inherent ionic compounds. The melt electrolysis of the FeS-Na2S system with the production of iron was carried out. Thus the possibility of transformation of the nature of conductivity of highly conductive chalcogenide melts of iron towards their electrolytic ability is proved. The obtained results must be taken into account when using electrochemical technology of processing polymetallic sulfide ores, which include metal chalcogenides of iron family. KEYWORDS: MELTS, IRON CHALCOGENIDES, NATURE OF CONDUCTIVITY, ELECTRIC CONDUCTIVITY, TRANSFORMATION, ELECTROLYTIC CAPACITY.

MATHEMATICAL SIMULATION AND STUDY OF CONTROL STABILITY OF THE CHEMICAL-ENGINEERING PROCESSES IN INDUSTRY

In this work is consider study and analysis of dynamic system for simulation of the technological process under uncertainty and complexity. To study and simulate a complicated technology process we carry out for consideration the technology of the process of roasting in fluidized bed furnaces of polymetallic sulphide ores. The choice is justified by the fact that, operation line producing of polymetallic sulphide ores represents a complex process, is characterized by a big number of transient processes, presence of process variables and deviations from technical regimes. To study process characteristics of any system functioning by means of mathematical methods the process should be formalized. This means, that adequate mathematical model needs to be developed. The choice of mathematical model depends a lot upon the features of the object and its controllability as well as of technological scheme and complexity of processes. Chemical engineering processes are complicated physical and chemical systems. Substance flows, which are part of these systems, are, as a rule, multicomponent. Therefore, for the purpose of study and qualitative control over chemical-engineering processes it is essential to apply the method of mathematic simulation, based on system analysis strategy, analysis of its structure, mathematical formulation development and evaluation of unknown parameters. Controllability means that such system attribute as having control actions, which make it possible to transfer the system from a pre-set initial state to the required condition during finite quantum of time. Therefore, the developed mathematical model of the process or control object should be controllable and stability.

Multi-scale impact crushing characteristics of polymetallic sulphide ores

Abstract The effects of crushing energy, ore hardness and particle size of cassiterite polymetallic sulphide ore and lead−zinc polymetallic sulphide ore on the crushing characteristics during impact crushing were investigated by mineral liberation analyzer (MLA) and drop weight test. The results show that both ores contain pyrrhotite, sphalerite, jamesonite, gangue mica and quartz except cassiterite. Cassiterite is closely associated with sulphide and quartz to form aggregates, which are mixed with each other in the form of intergrowth or symbiotic disseminated fine grains. Cassiterite has a significant impact on ore crushing characteristics. Ore hardness is negatively correlated with the product of crushing parameters of A and b, i.e. A×b, the effect of crushing energy on crushing fineness is related to crushing parameters A and b, and the influence degree increases with the increase of A. The influence degree increases with the increase of b when crushing energy ECS is less than 1 kW·h/t, and the influence degree decreases with the increase of b when crushing energy ECS is greater than 1 kW·h/t. The impact of crushing energy on crushing fineness is greater than that of ore particle size when the crushing energy is lower; on the contrary, the impact of ore particle size on crushing fineness is greater than that of crushing energy when crushing energy is higher.

A technique to determine ore variability in a sulphide ore

Ore variability is a big challenge for mineral processing operations, especially in the flotation of complex polymetallic sulphide ores. Processing and blending strategies are determined mostly based on chemical and mineralogical characterization. However, surface characteristics of sulphide minerals is an equally important parameter affecting flotation performance. Changes in surface characteristics of sulphide minerals are usually studied at laboratory scale by using sophisticated equipment, such as ToFSIMs, XPS, etc. In this paper, use of Oxidation Index methodology based on the EDTA extraction technique was evaluated for determination of the presence of secondary copper minerals and surface oxidation of sulphide minerals using a low grade VMS ore deposit from Turkey. These two surface chemistry parameters are known to influence flotation performance significantly, particularly in the copper flotation stage. Therefore, ore variability across the entire ore deposit was evaluated using the relationship between Oxidation Index and flotation performance. The results showed that this methodology can potentially be used as a practical and cost effective method for mapping an ore body regarding variations in surface chemistry of sulphide minerals, prediction of flotation recoveries and selectivity.

Environmental Impact of Mine Exploitation: An Early Predictive Methodology Based on Ore Mineralogy and Contaminant Speciation

Mining wastes containing sulfide minerals can generate contaminated waters as acid mine drainage (AMD) and contaminated neutral drainage (CND). This occurs when such minerals are exposed to oxygen and water. Nowadays, mineralogical work—when it is done—is independently and differentially done according to the needs of the exploration, geotechnics, metallurgy or environment department, at different stages in the mine development process. Moreover, environmental impact assessments (EIA) are realized late in the process and rarely contain pertinent mineralogical characterization on ores and wastes, depending on countries’ regulations. Contaminant-bearing minerals are often not detected at an early stage of the mine life cycle and environmental problems could occur during production or once the mine has come to the end of its productive life. This work puts forward a more reliable methodology, based on mineralogical characterization of the ore at the exploration stages, which, in turn, will be useful for each stage of the mining project and limit the unforeseen environmental or metallurgical issues. Three polymetallic sulfide ores and seven gold deposits from various origins around the world were studied. Crushed ore samples representing feed ore of advanced projects and of production mines were used to validate the methodology with realistic cases. The mineralogical methodology consisted in chemical assays and XRD, optical microscopy, SEM and EPMA were done. Five of the ores were also submitted to geochemical tests to compare mineralogical prediction results with their experimental leaching behavior. Major, minor, and trace minerals were identified, quantified, and the bearing minerals were examined for the polluting elements (and valuables). The main conclusion is that detailed mineralogical work can avert redundant work, save time and money, and allow detection of the problems at the beginning of the mine development phase, improving waste management and closure planning.

The selective flotation of chalcopyrite against galena using alginate as a depressant

In this paper, sodium alginate was put forward as a flotation depressant for selectively separating the chalcopyrite from galena. The effects of the sodium alginate on the flotation performance of chalcopyrite and galena were studied using ammonium dibutyl dithiophosphate as the collector. The adsorption behaviors of sodium alginate on the mineral surfaces were investigated through surface analysis including zeta potential, FTIR spectra and XPS spectra analysis. The micro-flotation results showed that sodium alginate exhibited selective and strong depressant effect on the galena flotation while had little influence on the chalcopyrite flotation, whether it was added before or after the collector. The surface analysis results demonstrated that sodium alginate could selectively adsorb on the galena surface and then hinder the subsequent collector adsorption thus resulting in the hydrophilic galena surface. The selective adsorption mainly consisted of the interactions between the Pb2+ on the galena surface and the functional groups in sodium alginate. Sodium alginate did not adsorb on chalcopyrite surface or interfere with the collector coverage on chalcopyrite surface. Based on these findings, a possible adsorption model of the sodium alginate on the water-solid interface of the two minerals was proposed. The paper shows that sodium alginate has the potential to act as an effective, non-toxic depressant in the flotation of Cu-Pb polymetallic sulphide ores.

Valorisation of a flotation tailing by bioleaching and brine leaching, fostering environmental protection and sustainable development

Flotation tailing is a problematic mining waste, because contains sulphides that exposed to oxidising conditions generate acidic drainage and the subsequent metal mobilisation. In this study, a flotation tailing produced within an integral process for the treatment of polymetallic sulphide ores is cleaned and valorised seeking a better use of natural resources and a lower environmental impact. In this work, bacterial leaching followed by brine leaching is postulated as an alternative to the flotation tailing treatment. Bioleaching destroys pyritic matrix (99% Fe) producing biogenic ferric that can be used as oxidising agent and recycling to a hydrometallurgical process. 80–90% Cu and Zn are dissolved and critical raw materials as Sb, In and Co are recovered. Brine leaching achieves Pb and Ag extractions greater than 96% and generates a solid residue mainly composed of quartz, in which gold that initially was in flotation tailing is concentrated. A clean and easily treatable for gold recovery final residue is obtained. In conclusion, pyrite matrix has been destroyed avoiding the further acid generation and reducing dramatically waste volume, metals have been valorised, and tailing hazardousness has been removed. Therefore, the proposed process is a sustainable alternative for flotation tailing management, reducing the environmental impact, the management costs, and generating income from valorisation of metals and the production of leaching agent.

AMT survey in the Outokumpu ore belt, eastern Finland

ABSTRACTThe Outokumpu belt in eastern Finland is known for numerous polymetallic (Cu–Co–Zn–Ni–Ag–Au) sulphide ore deposits and it is a potential area for new discoveries. Audiomagnetotelluric (AMT) data have recently been collected to image the subsurface conductivity structure of the belt. The data were acquired along five profiles aiming to explore deep conductors, study their geometry and investigate the deep conductivity structure of the belt.The acquired AMT data were mostly adequate for 2D inversion, as the survey area is characterised by thin, laterally extensive conductors indicated by airborne electromagnetic data, deep drillings and regional strike analysis of the impedance tensor data. 2D smooth inversion was carried out jointly for transverse electric and transverse magnetic data. The results show southeast-dipping and sub-horizontal continuous conductors southeast of the Outokumpu old mine, suggesting the presence of prospective Outokumpu assemblage rocks. One ∼ 1 km deep sub-horizontal conductor is verified by a deep drill-hole located ∼ 8 km southeast of the mine. The results demonstrate a similar southeast-dipping structure in the Vuonos mine area, which is located ∼ 7 km northeast of the Outokumpu old mine. An eastwards-dipping conductor detected in the Miihkali serpentinite area indicates deep exploration potential in this area. Besides the smooth 2D inversion, a sharp-boundary 2D inversion was performed and the resulting model was assessed with the existing geological interpretation of the Miihkali area. In the area of the Sotkuma gneiss inlier, conductors are absent from the uppermost ∼ 6 km. This feature may represent an uplifted fault block rather than a thin thrust sheet of Archaean basement rocks.

Research on prediction model of ore grinding particle size distribution

The prediction of grinding particle size is an effective measure to optimize the grinding process. Cassiterite polymetallic sulfide ore and lead-zinc ore, as the research object in this paper, their particle size prediction mechanism are studied based on the drop weight test, batch grinding test, the theory law of media motion in ball mill and population balance model. The results show that particle size distribution of crushing products under different crushing energies and ore particle sizes is obtained by drop weight test, and the crushing parameters A and b are calculated by fitting regression, and then the correlation between tx and t10 obtained in drop weight test is also applicable to the correlation between tx and t10 of grinding products in ball mill medium throwing motion, which can effectively solve the crushing function and the selection function with the help of Matlab, and then establish the grinding population balance prediction model based on the drop weight test and the motion law of ball mill medium. The adaptability and reliability of the prediction model of grinding particle size are verified by batch grinding test.

Grinding Optimization of Cassiterite-Polymetallic Sulfide Ore

Due to the differences in beneficiation methods and mineral properties between cassiterite ore and polymetallic sulfide ore, there is an inherent contradiction between cassiterite overgrinding and sulfide ore undergrinding. A method to optimize and characterize the grinding performance is presented in this paper. In this method, the grinding characteristics are defined by the qualified particle size range index under unit energy consumption. By changing the grinding time, grinding concentration, and filling ratio, the optimized grinding conditions were evaluated, and they were predicted and verified by the response surface method. The results corroborate that when the grinding time of cassiterite is 4 min and the grinding time of sulfide ore is 8 min, the grinding qualified size range index under unit energy consumption is the largest. Cassiterite is brittle and easy to grind due to low hardness, while sulfide is difficult to grind due to high hardness. Hence, the time to beneficiate tin ore is when the grinding time is 4 min, and that to beneficiate sulfide ore is when the regrinding time is approximately 4 min. In this way, the contradiction between overgrinding cassiterite and undergrinding sulfide ore can be alleviated on the basis of the most effective utilization of grinding energy. The optimal grinding concentration and filling ratio are 65% and 37%, respectively. The response surface prediction and test results are almost identical, with an error of ±2%. Thus, the effectiveness of grinding characterization method is verified.

The effect of whey protein on the surface property of the copper-activated marmatite in xanthate flotation system

In this paper, the depressant effect of the whey protein, a chelating agent for copper ions, on the flotation of copper-activated marmatite was investigated by micro-flotation, zeta potential, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). The results showed that the formation of a complex through the interaction between the copper ions and the whey protein effectively prevented the activation of marmatite from copper ions, and the flotability of the copper activated marmatite was remarkably decreased. The finding can potentially offer new choices for developing new reagents for depressing the copper-activated marmatite in flotation separation of the polymetallic sulfide ores.

Chemometric Analysis of Mid-Wave Infrared Spectral Reflectance Data for Sulphide Ore Discrimination

Despite significant recent advancements in the sensor technologies, the use of sensors for raw material characterization in the mining industry remains limited. The aim of the present study was to assess the utility of applying the mid-wave infrared (MWIR) reflectance data acquired by the use of a handheld Fourier-transform infrared spectrometer (FTIR), combined with partial least squares-discriminant analysis (PLS-DA), for the characterization of a polymetallic sulphide ore deposit. In achieving the study objectives, focus was given to the MWIR portion of the FTIR dataset, as it is the least explored region of the infrared spectrum in mineral characterization studies. Three datasets—covering different wavelength ranges—were generated from the FTIR spectral data, namely the full FTIR range (2.5–15 µm), MWIR (2.5–7 µm) and long-wave infrared (LWIR: 7–15 µm), in order to investigate the associated information level of each defined wavelength region separately. Design of experiment was developed to determine the optimal data filtering techniques. Using the processed data and PLS-DA, a series of calibration and prediction models were developed for ore and waste materials separately. As the models applied to the MWIR data showed a successful classification rate of 86.3% for sulphide ore–waste discrimination, similarly using the full spectral FTIR dataset, a correct classification rate of 89.5% was achieved. This indicates that MWIR spectral range includes informative signals that are sufficient for classifying the material into ore or waste. The proposed approach could be extended for automating the sulphide ore–waste discrimination process, thus greatly benefiting marginally economical mining operations.

The geometallurgical assessment of by-products\u2014geochemical proxies for the complex mineralogical deportment of indium at Neves-Corvo, Portugal

Many by-product metals are classified as critical. However, they are only of marginal interest to many mining companies and are rarely part of detailed resource statements or geometallurgical assessments. As a result, there is a general lack of reliable quantitative data on the mineralogy and spatial distribution of these metals in ore deposits—hampering assessments of future availability. We propose here an innovative approach to integrate by-product metals into geometallurgical assessments. As an example, we use the distribution and deportment of indium at Neves-Corvo, a major European base-metal mine (Cu + Zn), and one of the largest and richest volcanic-hosted massive sulfide (VHMS) deposits in the world. Based on a combination of bulk-ore geochemistry and mineralogical and microanalytical data, this study is the first to develop a quantitative model of indium deportment in massive sulfide ores, demonstrating how regularities in indium partitioning between different minerals can be used to predict its mineralogical deportment in individual drill-core samples. Bulk-ore assays of As, Cu, Fe, Pb, S, Sb, Sn, Zn, and In are found to be sufficient for reasonably accurate predictions. The movement of indium through the ore processing plants is fully explained by its mineralogical deportment, allowing for specific mine and process planning. The novel methodologies implemented in this contribution for (1) the assessment of analytical uncertainties, (2) the prediction of complex mineralogical deportments from bulk geochemical data, and (3) the modeling of by-product recoveries from individual mining blocks, are of general applicability to the geometallurgical assessment of many other by-product metals in polymetallic sulfide ores, including Ga, Ge, Mo, Re, Se, Te, as well as the noble metals.

An alternative approach to recover lead, silver and gold from black gossan (polymetallic ore). Study of biological oxidation and lead recovery stages

A novel procedure to recover lead, silver and gold from polymetallic sulphide ores, cleaner than the traditional hydrometallurgical route (hot brine leaching), is proposed. This process consists of a biooxidation stage, where sulphides are oxidised by the action of extremophiles, followed by an acid washing and a citrate leaching in which lead is recovered. The final solid obtained, mainly composed of quartz, is rich in silver and gold. This paper is focused on the biooxidation and the lead recovery of the black gossan, a polymetallic sulphide ore with valuable amounts of lead, silver and gold. Biooxidation performed with a mixed mesophilic culture (mainly Acidithiobacillus ferrooxidans) at 20% pulp density is able to dissolve the sulphide matrix, removing the gold refractory behaviour and producing jarosite, beaverite, gypsum and anglesite. A previous sulphuric acid washing of biooxidation residue greatly improves the lead recovery in the citrate stage. In the sulphuric acid washing, jarosite and beaverite are dissolved, being the most important variables the temperature and sulphuric acid concentration. The jarosite dissolution kinetics shows that the rate controlling step is the chemical reaction, with an activation energy of 86.4 kJ/mol. A linear relationship between the jarosite dissolved and lead recovered is found, reinforcing the necessity of a previous H2SO4 washing. The optimal pH range for lead recovery in the citrate solution is 5–9. Pulp densities higher than 5% produces an unstable solution, precipitating a part of the lead. A negative effect of gypsum has been confirmed through several citrate leaching tests performed with pure anglesite. The solid obtained after the studied stages is suitable to recover gold and silver that contains.

Identification of Surface Processes in Individual Minerals of a Complex Ore through the Analysis of Polished Sections Using Polarization Microscopy and X-ray Photoelectron Spectroscopy (XPS)

Understanding the changes of a mineral during ore processing is of capital importance for the development of strategies aimed at increasing the efficiency of metal extraction. This task is often difficult due to the variability of the ore in terms of composition, mineralogy and texture. In particular, surface processes such as metal re-adsorption (preg-robbing) on specific minerals are difficult to evaluate, even though they may be of importance as the re-adsorbed material can be blocking the valuable mineral and negatively affect the extraction process. Here, we show a simple yet powerful approach, through which surface processes in individual minerals are identified by combining polarization microscopy (MP) and X-ray photoelectron spectroscopy (XPS). Taking as an example a silver-containing polymetallic sulfide ore from the Peruvian central Andes (pyrite-based with small amounts of galena), we track the changes in the sample during the course of cyanidation. While polarization microscopy is instrumental for identifying mineralogical species, XPS provides evidence of the re-adsorption of lead on a pyrite surface, possibly as lead oxide/hydroxide. The surface of pyrite does not show significant changes after the leaching process according to the microscopic results, although forms of oxidized iron are detected together with the re-adsorption of lead by XPS. Galena, embedded in pyrite, dissolves during cyanide leaching, as evidenced by PM and by the decrease of XPS signals at the positions associated with sulfide and sulfate. At the same time, the rise of a lead peak at a different position confirms that the re-adsorbed lead species cannot be sulfides or sulfates. Interestingly, lead is not detected on covellite surfaces during leaching, which shows that lead re-adsorption is a process that depends on the nature of the mineral. The methodology shown here is a tool of significant importance for understanding complex surface processes affecting various minerals during metal extraction.

The flotation separation of galena and pyrite using serpentine as depressant

Toxic inorganic depressants are commonly used in the flotation separation of polymetallic sulfide ores and it is desirable that they can be replaced by environmentally benign substances. Serpentine, a common gangue mineral encountered in complex sulfide ores, has been found to be an efficient depressant for ferric sulfide (e.g., pyrite). Serpentine was tested as a potential selective depressant in the differential flotation separation of galena and pyrite using potassium butyl xanthate (PBX) as a collector. In single mineral flotation, serpentine depressed the −150 + 74 μm and −74 + 37 μm galena while the −10 μm galena was floatable. Different from galena, serpentine has strong depression effect on all the three sizes of pyrite. So the flotation separation of fine grained galena and pyrite can be achieved. A concentrate with Pb grade of 65.09% and recovery of 67.72% can be achieved in the mixed minerals flotation when serpentine was added as depressant. Mechanism studies indicated that serpentine particles attach to the surface of pyrite more easily.

Spatial distribution and geochemistry of major and trace elements from Mohoș peatland, Harghita Mountains, Romania

The Mohoș peatland is used as environmental archives of deposition for major (Al, Ca, Mg, Fe, and Mn) and minor elements (Cr, Cu, Ni, Pb, Sr, and Zn). The intense mining activity of Cu-rich pyrite and polymetallic sulfide ore from Bălan districts during the past centuries with a strong pollution impact was the reason why the Mohoș peatland, located in the vicinity of a mining area, was selected for this study. The mineralogical and chemical compositions of the peat have been determined by inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM), and x-ray diffraction (XRD). The identification of the main processes affecting the concentrations of the elements in peat was statistically evaluated by principal component analysis (PCA), and the identification of the main groups was determined by hierarchical clustering analysis (HCA). Our results revealed that the source of chemical and mineralogical peat samples is mainly geogenic with most of the elements being accumulated following the disintegration of parental material and through volcanic activity. For Pb, Zn, Ni, Al, and Sr, the concentrations were influenced by both natural processes and anthropogenic activities, such as mining, burning of fossil fuels, traffic activities, and metallurgy. Copper was influenced by anthropogenic activities. The distribution maps of trace elements were built only for the area in which the samples were taken.

Influence of dextrin on beneficiation of components from copper flotation concentrate

Depressants are one of the most important reagents in flotation process. They are used to improve upgrading selectivity. Natural depressants, especially starch and its derivatives, are one of the most significant polysaccharides used in polymetallic sulphide ores flotation. In the paper influence of dextrin on flotation of copper, organic carbon and mineral components from rougher concentrate was investigated. It has been shown, that dextrin is a good depressant for organic carbon and clay minerals with micas as long as the appropriate collector for sulphides are added. Moreover, significantly better flotation of all copper sulphides and pyrite with marcasite was observed, in comparison with flotation test using collector and frother only. Using dextrin as a single reagent does not affect beneficiation of examined concentrate. However, dextrin had not depressed galena particles. It can suggest that various factors can influence on good flotation of galena, e.g. associations with other sulphides, mineral composition and structure of examined feed.