Preliminary List of Abstracts (Alphabetical Order)

1ST INTL. SYMP. ON SUSTAINABLE MINERAL PROCESSING

In order to meet the specifications of the blast furnace process for steel production regarding trace elements content, upgrading steps can be required. Flotation has become increasingly important to process intermediate- and low-grade iron ore in an attempt to harmonize iron ore high-grade exhaustion and market demand of production in Brazilian sites. Following the Brazilian production expectation by 2020, the amount of flotation chemical will rise significantly. From a sustainable point of view, starch could have an issue of concern related to the availability, where industrial application for flotation process and the growth of population demand the same raw material. The scope of the present work is to develop a depressant with better selectivity than starch to achieve an upgraded pellet feed product from intermediate- and low-grade iron ores. A synthetic biopolymer, called XMC, was developed out of the food and feed chain with better selectivity index than starch. Therefore, the present investigation deals with the objective of increasing metallic recovery values by improving the process of reverse cationic flotation selectivity at competitive cost. For that, two different underflow iron ore samples after desliming stage were evaluated. Results show that at the same SiO2 level (about 1%), new biopolymer was able to foster a completive cost/benefit compared to the starch application on the cationic reverse flotation. The approached strategies were: A) increasing the metallic recovery and b) decreasing the SiO2 content for intermediate- and low-grade iron ore. For both iron ore samples, it was demonstrated that XMC requires significantly lower collector dosages than starch to achieve SiO2 values below 1% in the concentrate. This new depressant is an option for cleaning iron ore concentrates aiming at the production of concentrate products with SiO2 < 1%. Furthermore, friendly made down and application with lower Capex/Opex were expected, since XMC is already in gel form.

A major sustainable challenge faced by the aluminum industry is to provide solutions regarding the reuse of its major hazardous residues (red mud and spent pot lining). This investigation addressed the characterization of the two residues as a preliminary step in the search for potential geopolymeric applications. The techniques utilized were X-ray diffraction, XRD, and Fourier Transform Infrared Spectroscopy, FTIR, for the red mud (RM) and X-ray diffraction and X-ray florescence, XRF, for the spent pot lining. The presence of traces of crystalline and amorphous phases in the RM was detected by FTIR. These phases may enhance the geopolymeric properties and their type and amount depend on the bauxite ore characteristics. The SPL characterization indicated the presence of aluminum and also of other metallic elements that are deleterious for geopolymeric applications.

A new method for integrated processing of molybdenum sulfide concentrates by hydrogen reduction was elaborated. It allowed high degree of extraction of major components of the concentrate: Molybdenum (98.5%), rhenium (96%), and full recovery of sulfur (about 98%) from the gas phase in the form of sodium sulfide, which is a necessary reactant for the enrichment of copper and molybdenum ores. The studies were conducted using Kajaran (Armenia) molybdenum sulfide concentrate. The kinetic and thermodynamic parameters of the process were obtained. The optimal operation regimes were found experimentally on the enlarged laboratory setup. It was shown that the technology is environment-friendly.

The harmful effect of slimes on iron ore flotation performance is well known, but understanding the mechanism of interaction with the ore is quite complex. Thus, tests were carried out with itabirite ore in the presence of different concentrations of slimes presenting different mineralogical compositions in an attempt to explain the effect on the flotation process. Three samples of ores and four samples of distinct slimes were selected. The results showed that the slimes consisting mainly of hydrated minerals had the least influence on the flotation performance and the slime with the highest content of alumina, titanium, and manganese caused the greatest impact on flotation, especially on its own ore. Analyzing the surface area of the samples, the zeta potential of the slime and the results of flotation, it was possible to conclude that these features are not the factors responsible for changes in the grades of silica in the concentrate, since for all tests with similar amounts of slime, the values for the specific surface area and the zeta potential were similar for all slurries under investigation at the flotation pH. Understanding the behavior of slimes is important for the yield is increased when flotation accepts ultrafines.

The effect of high-power (high-voltage) nanosecond electromagnetic pulses on chemical and phase surface composition, structural-chemical, electrophysical, electrochemical, physical-chemical and flotation properties of sulfide minerals has been studied in our previous investigations (see for example, Chanturiya V.A., Bunin I.Zh., Ryazantseva M.V., et al. Theory and Application of High-Power Nanosecond Pulses to Processing of Mineral Complexes // Mineral Processing and Extractive Metallurgy Review - 2011 - Vol. 32 . - No 2. - PP. 105-136).This work presents new experimental data on possible mechanisms for the formation of micro- and nanostructures on the surfaces (surface nanophases) of sulfide minerals (sphalerite and chalcopyrite) under the effect of high-voltage nanosecond pulses.The morphology, sizes, and elemental composition of nanostructures on chalcopyrite and sphalerite surface have been studied by scanning electron microscopy (SEM, LEO 1420 VP), X-ray spectral microanalysis (XRMA, EDS, INCA Oxford 350 X-ray microanalysis system), and scanning probe microscopy (AFM, INTEGRA Prima, NT-MDT). The results of SEM-XRMA investigations of the surface structure of chalcopyrite and sphalerite indicate the formation of defects (breakdown channels and microcracks) and the forced formation of new micro- and nanophases on sulfide surfaces, due to electric pulse processing. In addition to intensity peaks corresponding to Fe, Cu, Zn, and S, a pronounced peak corresponding to oxygen has been traced in the X-ray spectrum of a surface from the region of localization of neoformations, possibly indicating the formation of autonomous and nonautonomous phases.It is established that electrode potentials of chalcopyrite and sphalerite are moved together in the positive party owing to formation of cuprum, zinc and iron oxides (hydroxides) and cuprum, zinc and iron sulfates by nanosecond pulses that provides increase of xanthate sorption and increase in flotation extraction of these sulfides.

The dry physical coal beneficiation method, Air Dense Medium Fluidized Bed (ADMFB) system, can offer an efficient solution for ROM ash removal to improve coal quality and restrict its application issues and footprint. In this study a full-factorial (23) experiment design method was used to study the effect of main operating parameters and reveal their mutual interactions on ADMFB performance when dealing with western Canadian sub-bituminous coals (31% ash). This technique was used to avoid any misleading interpretations based on the traditional one factor at-a-time methods. The superficial air velocity, U; Residence time, T; Bed height, H; Coal particle size and fluidization medium size were the key influencing parameters affecting the apparatus performance. System separation efficiency and product (clean coal) ash content as well as organic material recovery are selected as response functions. Statistical analysis of the results on the three selected responses determined negative effect of increase of U and T on organic material recovery while H was affecting that positively. Two interactions between U and H, and, T and H were also revealed at 95% confidence level. The U and T had positive and negative effect on product ash content while H had no significant effect. The mutual interaction of T and H was found even more effective on product ash content than the direct effect of T. U and H had positive effect on separation efficiency where T and the interaction between U and T were negatively affecting efficiency. Considering the determined effectiveness of the operating parameters; U=16.5cm/s, T=90s and H=15cm were determined to be the optimum settings. Optimization of separation process resulted in product ash content, recovery and separation efficiency of 13.2%, 67.7% and 48.1% respectively for a feed with 31.5% ash.

Electrochemistry of sulphide minerals is the subject of many researches due to its semiconducting properties and the possibility of metals extraction associated with them. This study evaluated the electrochemical behavior of chalcopyrite (CuFeS2) and galena (PbS) samples, in the light of electrochemistry, in order to evaluate the effect of interaction between the different samples on their potential values in the absence and in the presence of previous oxidation of mineral surfaces. The rest of the potential measures have been taken in relation to a saturated calomel electrode (ECS; E0 = 0,242 V) for a period of 120 minutes in the presence of air, in the absence and presence of electric interconnection between them. In the absence of interaction, chalcopyrite suffered oxidation while galena was reduced. When the electrodes were connected electrically, chalcopyrite exhibited similar behavior, but galena behaved similarly to chalcopyrite surface; This same behavior was also observed in previously oxidized electrodes.

Copper ore deposit Veliki Krivelj belongs to porphyry copper ore with low copper grade. The main copper mineral is chalcopyrite and minor chalcocite, but the principal sulphide mineral is pyrite. Testing ore samples had low copper contents about 0.25% Cu. The classical flotation scheme by collector xanthates does not offer satisfy results on copper recovery and concentrate grade. An extensive investigation on laboratory conditions with collectors type tiono carbamates led to good results on flotation recovery and concentrate grade as well as a little bit in energy saving in grinding process. The obtained results will be presented in the paper in shorter form.

Most people will agree that right and wrong are opposites, but in a complex system, this may not be the case. Instead, right and wrong are complementary functions in which the boundary between the two concepts consists of a region in which right and wrong are partially correct. The decision to do the "right" thing within this region must wait for more information; Or must account for the fact that what is right for some people might be wrong for others; Or what is right at this time or place is not right at another time or place. Accordingly, choosing what one should decide to do becomes dependent on the collective importance of the various supporting and denying pieces of evidence, with the individual importance of each piece being measured by the person making the decision. In other words, a compromise is required. When one is within this boundary, a dialogue with those that have knowledge must take place that can be brought to bear on the problem. But even a dialogue has a degree to it. The depth and extent of the dialogue are affected in that a quick decision may be required which places a significant constraint on the discussions. If that situation exists, after the decision is made, great care is needed to monitor over time to see if any modification is required as time passes. The degree of monitoring may also be constrained since there may be adjacent problems that require attention at the same time leading to a reduction in the resources (time and effort) that can be expended. This paper will present a theoretical model to analysis how fuzzy logic and accumulated knowledge can impact on human decision-making. Examples from the mining industry will be used to illustrate the concept.

So far, milling has been an area that has stood out as one of the biggest costs in mineral processing industry. The inner lining of the mills has been taking greater prominence due to its direct influence on the grinding efficiency and the high aggregate cost related to its operation time. Once the lining attrition is not uniform, the monitoring of the lining attrition of the ball mill (SAG 4.87 x 6.09 m) of Vale Fertilizantes S.A. Catalao-GO Unit Company was performed. The mill works with phosphate ore and the monitoring was carried out using a practical device aiming to determine the behavior of lining attrition along the entire length of the mill, from the feed to the discharge, and the profile variation in a single lining plate. It was observed that the lining attrition was not uniform both along the mill and in a lining, indicating that the higher lining attrition occurs in the first and lasts 1.5 meters with very close values. At the mill feed, the specific lining attrition was equal to 0.60 g/t, in the discharge it was equal to 0.63 g/t and in the center of the mill it was around 0.55 g/t.

The development of Life Cycle Assessment (LCA) software tools over the last 25 years has been well documented in a variety of products and processes, in a multitude of industries. Regardless of the industry or application, mineral processing activities are instrumental in the production and development of these practices, and the focus of sustainable development in mineral processing activities has the potential to effect many downstream industries. Until recently, LCA has rarely been applied to mineral processing and mining related activities, and this paper aimed to look at some of the advantages and disadvantages of this tool, and how the results of LCA can be used to promote sustainable development in the mineral processing sector. This paper overviews some of the previous work done with LCA in different processing applications, while also conducting a LCA of a singular processing related activity (coal flotation). The coal flotation LCA in this paper was used as an illustrative tool of how process-based LCAs works, and how it can be applied to sustainable development, more so than as a formal study. The goal of this paper is to show not only the potential benefits and advantages of using LCA to assist in sustainable development, but also to comment on some of the short comings and hazards of relying on LCA results.

A challenge for sustainability in the mining industry is the use of toxic or harsh reagents for separation of mineral components. We present here a biotechnology approach which has the potential to improve mineral separation efficiencies, while also using biodegradable flotation agents that are effective at neutral pH conditions. The biotechnology approach is based on phage display, where phage (virus particles) are genetically modified to 'display' a different peptide on their 'tail' proteins, with around 109 different peptide combinations available from a commercial phage library. This library of phage clones can be placed in a solution containing the target material of interest, where the phage that happen to bind to the target are collected, and then subjected to another 'biopanning' round in order to 'evolve' a set of phage clones that have strong binding affinity to the target. From this group of clones, one can then chose the clones that do not bind to the undesired material, in order to achieve a specificity in binding. We demonstrate this biotechnology approach using a specific example based on the Florida phosphate mining industry, which is concerned with the separation of dolomite (CaMg(CO3)2) contaminants from the desired francolite mineral (a fluorapatite (Ca5(PO4)3(F,OH)), which have similar surface chemistries, and are therefore notoriously difficult to separate. Using phage display, we screened for phage clones that had a strong and preferential binding affinity to Francolite, relative dolomite. The coat proteins of phage are relatively hydrophobic, which enabled the phage to be used as bioamphiphiles for flotation, where they concentrated the content of francolite relative to dolomite from 25% to 42% in a bench-top flotation apparatus. The potential for using this biotechnology approach for commodity applications is discussed, where we believe that phage can provide a renewable 'surfactant' for environmentally-benign particle processing.

Nowadays, the mineral processing tailings disposal is a big problem due to the environmental degradation produced. The use of tailings dams is a globally used solution, but it generates very large impacted areas where soil, fauna and flora are equally suppressed. The present work proposes the mineral paste production with the tailings from phosphate rock in two stages. The first one was composed by the free settling of the material in presence of industrial flocculants. The second one was composed by the tailing filtration using a geotextile as filtration media. The used tailing samples were produced from Anglo American Fosfato Company, Ouvidor/GO unit. The results found were satisfactory for mineral paste production with solid grade around 35%.

In Curimatau Microrregion, Paraiba State, Brazil, the Borborema Pegmatite Province is characterized by the presence of intrusive pegmatites dikes and sills in meta-sedimentary sequences of Serida Group. These igneous bodies are presented concentrically zoned, with a core of quartz, feldspar developing bands ranging from albite to sanidine, pure or intergrowth with quartz, disseminated or concentrated muscovite, decreasing grain size towards the contact with the host rock. The crystallization of beryl, aquamarine, tourmaline and tantalite complete the petrographic framework of pegmatite bodies. The economic importance of mineralogical group has attracted the attention of researchers since the early twentieth century, including the United States Geological Survey, which explored tantalite in this region aiming to supply raw material for making weapons of war during World War II. At the time, the miners with the unplanned practice extractive which endures to present days. Recently, strengthening cooperatives in the mineral region have brought significant improvements on mining, causing a systematic organization of its members, regulating areas with the DNPM, acquiring safety equipment and instrumentation for the various stages of mining and mineral processing, such as panning, milling, and gravimetric concentration. This set of actions has led to significant improvements in economic conditions, environmental and social sustainability in mining.

Ores are heterogeneous materials from which metals are extracted. The heterogeneous nature of the ores makes extraction modeling challenging. New methodologies that characterize the relationship between valuable mineral grains and host rocks as well as the effect of comminution on that relationship facilitate improved modeling of leaching of crushed and ground ores in heap and tank leaching. These methodologies can be combined with additional techniques to account for heap leaching application scenarios that involve curing, point source solution application, and stacked ore compressibility in order to provide improved insights and accuracy in heap leach modeling. This presentation will describe the associated methodologies and techniques as well as provide a comparison of modeling and experimental results.

In the differential metal sulphide ore flotation, it is desirable to replace the toxic inorganic depressants with environmentally benign chemicals. Chitosan, as a natural and non-toxic material, has been proven to be an efficient depressant for chalcopyrite, while allowing galena to be floated by xanthate collectors. However, the poor solubility of chitosan limits its potential applications as the flotation could only be carried out at pH 4, where chitosan is soluble. A carboxymethyl derivative of chitosan, named N-carboxymethyl chitosan (N-CMC), was synthesized by replacing the amino groups of chitosan with carboxymethyl groups. The substitution improved significantly the solubility of chitosan. The structure of N-CMC was investigated and compared with chitosan via Fourier transform infrared spectroscopy (FTIR). Both micro and batch froth flotation tests were performed on single minerals and mineral mixtures (with weight ratio of 1:1) with the addition of appropriate amount of potassium ethyl xanthate (KEX, a collector) and N-CMC to study the selectivity of N-CMC between chalcopyrite and galena. The solution pH was varied from neutral to alkaline. The flotation concentrates and tailings were collected and analysed for the content of copper and lead by using an atomic absorption spectrometer (AAS).The results of FTIR showed new peaks of C=O stretching of -COOH and N-H deformation of -NH- appeared in N-CMC, which proves that the carboxymethyl groups were introduced and amino groups were the sites for substitution. The flotation tests at pH 7 and pH 10 showed interesting depressive functions of the N-CMC. At pH 7, chalcopyrite was depressed by N-CMC and galena was floated, whereas at pH 10, galena was depressed by N-CMC and chalcopyrite was floated. The results did not seem to be affected by the sequence of KEX or N-CMC addition. Therefore, the N-CMC is potentially useful in Cu-Pb sulphide separation following a bulk Cu-Pb sulphide flotation.

In the process of stainless steel production using ferrochrome, electric arc furnace melting and argon-oxygen decarburization 10-20 kg of dusts per ton of steel are produced. In addition, the final rolling and pickling stages produce significant amounts of metal-rich wastes and acid sludge. The dusts are usually treated by pyrometallurgical methods, such as plasma processing or Waelz kiln. Hydrometallurgical methods have been developed, especially for the recovery of zinc from Electric Arc Furnace (EAF) dusts. Most of the research has been focused on treatment of EAF dust from production of unalloyed steel. A new concept has been developed to selectively leach out zinc from the dusts, enabling the remaining iron, nickel and chromium compounds to be recycled to melting. Using either a strong alkaline solution or strong acid solution, zinc can be dissolved. Factors affecting the leaching efficiency have been determined. Mineralogical factors limiting the zinc dissolution have been determined and pre-treatment methods have been developed. Using the optimal conditions, the zinc level in the treated dust has been in the order of 0.1 wt-% allowing recycling of the dust.

The technology of direct electrochemical processing of copper sulfide concentrates was developed, providing the following processes: Electric smelting of concentrates on matte, casting the last into anodes and their temperature control; Electrolysis of sulfide copper-iron anodes, obtaining high-quality copper powder; Crystallization of iron sulfates and extraction of elemental sulfur from anode sludge.The proposed technology has a number of important advantages over existing pyrometallurgical methods, such as the environmental safety. The main steps of the proposed technology were tested in semi-industrial scale.

The relationship between ore composition or mineralogy and downstream processing is well known in the mining industry. In fact, the very definition of a mineral deposit as an ore body depends on its susceptibility to processing in an economical manner. With an ore tracking system, the information about each ore block, gained during exploration and mining, could be used as input data to the mine control system. This would allow the real-time optimization and control of the ore processing.A smart ore tracking system can be developed by using soft sensor technique. The ore tracking system utilizes the real time information available in both SCADA and database of a mineral processing plant or a mine. Using the ore geological data and the tonnage of ore being treated, the ore tracking system calculates and provides ore type information such as ore mixing percentage, ore grade and ore density. The ore type information provided by the ore tracking system can be made available at all process units at a mine, including primary crusher, primary stock pile, primary scrubbers, secondary scrubbers, secondary crushers, re-crusher stock pile, DMS stock piles, DMS feeders, DMS concentrate bin and the feed to next processing plant. The ore tracking system, developed originally for a diamond mine, can be used for other mines, including iron ore mines, coal mines, copper mines, chromium ore mine, etc.

With the advancement and the wide usage of measurement instruments associated with stockpiles, such as weightometers, a soft sensor can be developed to monitor the level of a stockpile. Furthermore, the stockpile soft sensor can be used to determine the mixing behaviour of different ores discharged out of the stockpile, by combining the soft sensor technique and DEM modeling. The mixing behaviour of different materials includes when and how the mixing takes place, and more important, when the mixed materials with a certain portion is discharged out of the stockpile. In this article, only the level function of the stockpile soft sensor will be discussed in detail.The stockpile soft sensor can help estimate accurate residual time for different group of ores charged to the stockpile. The soft sensor makes it possible to monitor the behavior of different ore types in real time in a stockpile, including when and how the different ores are mixed in the stockpile and when the mixed ores are discharged with certain mixing portion. Using the soft sensor system, the information on ore types can be provided for ores that are discharged from the stockpile. The ore type information includes ore grade, density, hardness, strength, etc. The stockpile soft sensor forms part of an ore tracking system, which utilises the real time information available in both SCADA and database of a mineral processing plant or a mine. Using the ore geological data and the tonnage of ore being treated, the ore tracking system calculates and provides ore type information to all process units at a mine, including primary crusher, primary stock pile, primary scrubbers, secondary scrubbers, secondary crushers, re-crusher stock pile, DMS stock piles, DMS feeders, DMS concentrate bin and the feed to next processing plant. The stockpile soft sensor, developed originally for a diamond mine, can be used for stockpiles of other mines, including iron ore mines, coal mines, copper mines, chromium ore mine, and even cement plants, etc.

The ore beneficiation at a mine could be described as complex and expensive, involving many balancing processes where material flow rates, size, density and other factors must all be in balance, if any degree of plant optimization is to be achieved. To determine the optimum setup for maximizing throughput at the final step in the beneficiation process, such as the dense media separation units, a mine optimizer is developed using constraint-based global optimization. The Mine Optimizer uses plant unit availability, capacity in tons per hour (t/h), change in material size (between crushers) and other constraints. The result is that improving cheaper upstream processes, such as blasting, can significantly increase the throughput of expensive downstream processes, like crushing, through improved fragmentation of the ROM ore. For instance, if the ROM ore is not in the required range, the plant production is unbalanced and consequently the mine could loss production by 10-20%, even 50% in the worst case. On one hand, a finer ROM ore may result in lower utilisation of both crushing and coarse separation by 50%. Meanwhile other process units are running at 100% capacity, such as slime and tailing dumping. In addition, a finer ROM ore may destroy the mineral value as well, such as in the cases of mining coal, iron ore, and diamond ore, where a higher price is for the products of larger size.

The thermodynamic studies of desulfurization processes of sulfides of non-ferrous and rare metals were studied. The calculations were performed using the thermodynamic database and NVTANTERMO software. On the basis of these calculations, the experimental investigations of desulfurization of sulfides of copper, lead, zinc, iron, silver, as well as collective polymetallic concentrates of Shahumyan deposit in Armenia were carried out. In the processing of reducing gases (H2 + CO), water vapor and steam-air mixture were used. The experiments showed that, from an economic point of view, the most efficient processing method is a steam-refining of concentrates. This method significantly reduces the energy expenses, process duration and ensures high degree of extraction (97 - 98%) of the major components. Besides, this method allows obtaining sulfur in elemental form.All this makes possible to organize an economical waste-free and ecologically clean processing of polymetallic concentrates.

Phosphate rocks (PR) are constituted by a calcium phosphate mineral: Apatite. Two main rock types are used: Marine sedimentary and volcanic igneous; For the production of phosphoric acid (PA). It is an important industrial chemical, utilized as an intermediate in the fertilizer industry, for metal surface treatment in the metallurgical industry and as an active additive for solid food , fruit juices and beverages, e.g. Cola-type drinks to impart tasty, slight acidity and to avoid iron sedimentation. Direct application of ground PR is practiced in tropical acidic soils to increase the pH and to improve the soil texture. PR is converted into PA by two processes: The wet process (WPA) by leaching with H2SO4 and by a novel process by treatment with HCl followed by separation applying solvent extraction (SX) technology. PRs contain many impurities; Fluoride, chloride, Fe and Al oxides, pyrites and fossilized organic matter, which interfere with production, impair the PA quality and enhance corrosion of the plant equipment engineering materials. Sometimes clays and silicates are added to the WPA reactor to reduce the reaction corrosivity. The PA industry is spread out in LA countries: Mexico, Venezuela, Colombia, Brazil and Peru, which operate PR mines and produce PA and phosphatic fertilizers. The production problems and the solutions implemented to increase gypsum filterability reduce corrosion, and noxious gases emission and improve the quality of the product, will be presented and illustrated, based on the author's experience and knowledge.

The objective is to produce pellets of lower cost with the appropriate technical qualities, to be used in metallurgic reactors, using fine manganese ore and additional substances, there by substituting the grinding stages, thickening, and homogenization and filtering by grinding in the roller press, thusly eliminating the stage of prior calcination of the ores. For the grinding process, only the particles with a size smaller than 1mm were selected. Limestone powder and binder were added to the ground ore and the components were mixed. During the agglomeration process, water is added to the mixture until the appropriate humidity is reached, there by producing crude pellets. During the thermal process, the crude pellets undergo stages of controlled drying, pre-burning and burning. Through knowledge of the mechanisms of transformations of phases with the increase of the temperature, to which the ore is subjected, it is possible to elaborate an appropriate thermal cycle to control the burning stage, reducing in that way destructive effects and degradation of the pellets, obtaining a product with chemical qualities (reduction / elimination of the heavy elements), physical qualities (high compression strength and low abrasion index) and metallurgic qualities, to withstand effects of handling, long distance transport and processing in the reactors.

Brazil has large reserves of coal (30 billion tons) located predominantly in the south of the country. Despite the relative ease of exploitation, these resources have been underestimated as a source of energy. Currently, the country's strategic planning aims to minimize the gap between coal and resources traditionally used in the Brazilian energy matrix. In this scenario, the processing of Brazilian coal in columns flotation appears as a promising alternative, having been successful in mineral systems containing fine particles. This paper aims to study the overall process of column flotation for a specific Brazilian coal.The sample used for this study is a material deposited in the tailings dam of the coal mine "Carbonifera Criciuma", located in the south of Brazil. Usually, the coal fines, along with the mineral part from the beneficiation process are called "sludge", are discarded as waste and deposited in the tailings pond. The recovery of coal fines can facilitate the obtainment of a concentrate that could be used as fuel in power generation. It can also contribute as a factor of environmental impact reduction by minimizing the formation of acid mine drainage (AMD), generated by the sulfur contained in the material under study, in addition to reducing the physical space occupied by the tailings dam. Among the methods coal beneficiation, flotation stands out as one of the most important concentration process, particularly in the treatment of fine particles. The characterization allowed us to define that we are working with a material 83% lower than 0,710 mm. The results showed that, from a feed with around 63% of ash content, we can get a concentrate with 30% of ash content and 40% of carbonaceous mass recoveries.

The recovery of iron bearing minerals from the reject products of the processing of iron ores is a challenge regarding the sustainability of the operation of concentrators. This paper describes two case studies addressing the concentration of fine particles from Samarco's concentrator I desliming cyclones overflow and from VALE's Brucutu concentrator slimes thickener underflow. Samarco's investigation included stages of micro-desliming and flotation. The concentrate produced via cationic reverse flotation presented silica content compatible with pellet feed requirements. VALE's investigation comprised four concentration routes, namely: Pilot scale magnetic separation as rougher stage and conventional mechanical flotation as cleaner stage (route A), rougher and cleaner stages laboratory scale flotation (route B), rougher stage followed by three scavenger stages gravity separation in Falcon centrifugal apparatus (route C), and rougher, cleaner, scavenger I and scavenger II magnetic separation stages (route D). The best overall result was achieved from route D. The expected total production would reach 363,000 metric tons per year of concentrate with grades 66.8% Fe, 0.80% SiO2, 0.97% Al2O3, 2.45% LOI. In both cases, the total mass of reject products should be decreased, the life of the tailings pond would be increased, and the resulting environmental impacts would be mitigated.

Old tailings dams and dumps are receiving increased attention by industry and governments because of the need to remediate legacy sites that are significant liabilities. The opportunity to retreat old tailings dams to generate a valuable product can significantly offset the costs of remediation. Re-processing of old tailings dams can often generate positive cash flows while at the same time improving long-term liabilities. A spreadsheet model has been developed to assess environmental and social benefits that derive from retreatment, together with potential economic positives. The system simulates human decision-making about these matters using fuzzy logic and fuzzy-neural equations in which data can be input as measured numbers or as linguistic terms of relative magnitude. There are four modules in the system: Economic and Design Module; Disposal and Reclamation Module; Risk Assessment Module; And a Decision-Making Module. The system can conceptually design all process activities from re-mining through to reclamation; Perform a balanced evaluation of the economic, environmental and social benefits; And assist in multi-criteria decision-making. Four hypothetical cases are described to validate and verify the model.

Molybdenum mine is spread on the territory of Mongolia in the main form of copper-molybdenum ore, and there were found rich deposits like Erdenet, Tsagaan-Suvarga and Oyu-tolgoi. The molybdenum mining process used at Mongolia Erdenet Company.Ltd is a selective flotation of molybdenite from the copper porphyry ores in which the extraction of molybdenum comes as a byproduct of the ongoing copper production.The experimental technological procedures and analysis were performed on the molybdenum concentrate of Erdenet. The mineralogical composition of molybdenum concentrate is 99.4% molybdenite (MoS2), 0.09% molybdenum oxide (MoO3), 0.52% powellite (CaMoO4) and wulfenite (PbMoO4) and content Mo 47.76-47.92%, Cu 1.5-2.67%, Re-0.04%. After mechano-chemical activation, the oxidized burning temperature of Mo-concentrate decreased from 5500C to 450-5000C and burning time decreased from 2 hour to 1 hour. The optimal regime for the calcium molybdate precipitation from molybdenum ammonium solution: PH= 9, temperature 400C and the result of X-ray is suited to chemical pure calcium molybdate. The optimal regime for molybdenum acid crystallization: PH=2, time is 6-7 hours. By direct evaporation of ammonia extract of molybdenum concentrate, we obtained ammonium par molybdate, which contains 73.47% MoO3.

The grains handling always need a storage form that prevents the loss of materials and takes easy the following operations, which are often in form of silos or stoke piles. This presents some disadvantages, like the environmental exposure and the difficulty in feeding downstream operations. The silos keep the particles in a closed volume and direct the flow to an orifice during the unloading, so it has been a very efficient alternative in the use of fines and for subsequent handling. However, the knowledge about the properties of the particles like density, size, angle of friction and attrition are absolutely important, because in combination with the silo geometry and the amount of grains, tensions arcs in the discharge can be cause, preventing the flow.The present work was developed to find relationships between the flow time and these variables. The orifice width, hopper inclination and height were restricted in relation to the equipment geometry. For this, we used the modeling and simulation 3D software Blender, version 2.68, created by Blender Foundation with free access and the methodology based on Computer Fluid Dynamics (CFD) tools. In the simulations, it was noticed the importance of the particles flowability in the flow time, which is conditioned, mainly, by the grains size and angle of flow. The humidity as well as time the granular package was in the bin before being discharged were despised, but they can influence in the flow time.

In order to find a new way to utilize the high phosphorus oolitic hematite ore as raw material for steelmaking, the reduction and carburization of high phosphorus oolitic hematite by the gas of CH4-H2 were studied. The behavior of the gangue in process was investigated. High phosphorus oolitic hematite, reduction and carburization products were investigated by the means of XRD and scanning electron microscope. The main compositions of this ore are hematite and quartz, and main microstructure is oolitic cluster with the zonal distribution of hematite and apatite. The high phosphorus oolitic hematite pellet was reduced and carburized by CH4-H2 gas in the temperature range from 923 K to 1073 K. The reduction of high phosphorus oolitic hematite was promoted effectively by increasing the temperature in the range of 923 K to 1023 K, but the carburization was retarded with increasing temperature. The SEM and EDS analysis of the reduction and carburization products proved that phosphorus in gangue was mostly not reduced and still existed in apatite during reduction and carburization reaction.

Mining and smelting in Bor Basin is over one hundred years old during which the rich copper ores has been excavated and processed by pyrometallurgical routes. In 1930's the flotation process to produce useful concentrates from ores was introduced due to the fact that copper grade in ores was decreasing. The increase of mining volume generated large amounts of waste materials in the form of solid, liquid and gas. Mining wastes (mining and flotation tailings) consist of about 650 Mt solid materials which is estimated to contains about 750.000 t of metal copper. All the wastes have a negative environment impact but flotation tailings are really a complicated issue. On one hand they contaminate water because they leak from tailing pond in nearby rivers and on the other hand they contain valuable elements such as Cu, Ag, Au, with an average content of copper 0.3%, gold 0.8 g/t, silver 2.4 g/t and sulfur 12.7 %. These valuable components can be extracted from these tailings through their reprocessing and recycling. The process normally consists of following main steps: Excavation, repulping, attrition, bulk sulfide and precious metals flotation, bulk concentrate treatment by selective flotation and newly obtained tailings returning to the old closed open pit mine. Extensive laboratory work was undertaken to obtain flotation bulk concentrate with good recoveries of above-mention valuable compounds. For instance, copper recovery in the bulk concentrate was achieved up to 98%. Present activities are orientated in bulk concentrate selection by flotation in order to separate copper minerals from pyrite. For mineral liberation and surface cleaning prior to flotation the attrition technique was applied rather than regrinding. This paper describes the laboratory results of flotation followed by attrition on copper minerals and pyrite. All proposed routes are based on sustainable development concepts applicable in a wide area.

Samples of molybdenum sulfide concentrate of Kajaran deposits in Armenia were subjected to oxidation in the atmosphere of water vapor in pilot plant with capacity of 2 kg per hour. It is shown that the rate of sulfur oxidation in the presence of water vapor depends on the reactor temperature, on organization of transport of the reaction products from the surface of treated samples, on the particle size of concentrate and other factors. The optimal process parameters which provide a high degree of molybdenum extraction (98.5%), as well as rhenium (99.6%) and sulfur (98%) in the form of elemental sulfur or sodium sulfide are revealed. The technology is characterized by high environmental safety.

The flotation process of complex sulfide ore of Pb and Zn, even after 100 years of experience, in terms of process control, is a challenge. The Empiric control of the process, based on the intuition of the operator, is considered "base manner" of control. To improve relevant technological indicators, good experiences are accumulated from the past, as well as theoretical developments are reviewed, which are combined with achievements in the development of computer hardware and software. Algorithms have been developed to conduct the process state and to realize necessary reactions in case of disturbances. Based on these, inside computer HD has created one processing Database, in a form of Situations and Actions. Created situations are an example of neural network constructs, whereas the actions are implemented in accordance with fuzzy logic rules. The process always learns from creating situations and actions, thus moving towards intelligent computer systems. Expanding the database, based on its learning system from the past, strengthens the role of the computer in effective control of the mineral processing plant.

Actual annual production of high grade chromium ores suitable to be treated in metallurgy in Albania is about 270 000 ton. The Cr2O3 content varies from 32% to 48%. Only about 100 000 ton per year are treated in Albania for ferro chromium production, the other quantity of about 170 000 ton per year is exported mainly to China. Chromium ore produced in the biggest mine of Albania, in Bulqiza, is treated by hand picking in particle size -300 + 70 mm, separating chromium product with 42% Cr2O3 content. The fractions under 70 mm contain 32 % Cr2O3 for the high dilution during mining underground. The heavy media separation plant in Klosi is processing the fractions -70 mm + 10mm to upgrade chromium product acceptable in metallurgy for ferro chromium production and it is studying the possibility of crushing and treating of all mine production. The flow sheet and technological economic evidences of this plant are described in the present paper aiming profit calculation of mineral processing of high grade chromium ores that need upgrading to be used in metallurgy for ferro chromium production. Different parts of chromium body in Bulqiza mine have different characteristics to be upgraded and need a certain separation density of heavy media separation. The used methods of mineral processing include testing in industrial scale to find optimal parameters of heavy media separation created with ferrosilicon. It is concluded that chromium ores with about 32%-36% Cr2O3 content can be upgraded to 36-42% Cr2O3 content product in drum heavy media separation with recovery of Cr2O3 over 90% against feed in the drum.

The minerals industry has been adopting new strategies to reduce energy and water consumption, as well as greenhouse gas (GHG) emissions, which, in turn, can be regarded as environmental impacts from the standpoint of sustainability. In spite of the important efforts that have been made towards this goal in plants during their operation, it is evident that the greatest opportunity in reducing these impacts for an industrial operation is in the design stage of the plant. However, in spite of this potential, only a few experiences and systematic implementations based on sustainability principles have been undertaken in the minerals industry. The present paper proposes a methodology based on sustainability principles applied to beneficiation operations, using a simplified Life Cycle Assessment (LCA) based approach. The proposed methodology has special emphasis on comminution of Brazilian ores, having been applied to itabirite iron ores, whose beneficiation is becoming strategic for current and future projects in Brazil.

Although the mining industry is very important for the economic and social development of any country, it is still seen as highly harmful to the environment. The current economic scenario has been increasingly requiring assurances that extractive activities are developed within the concept of sustainable development, i.e., they meet the basic principles of environmental responsibility and economic viability, without neglecting the demands of the future generations.In this context, this work is part of the re-evaluation of processes and inputs used in the mineral industry and it aims to verify the possibility of using residual frying oil as an anionic collector in phosphate ore flotation. This study may provide an important strategic contribution to the sustainability in the mining sector, since this oil is a residue generated in large volumes and it is one of the main problems faced by the food industry. The residual frying oil is attractive in the sense that, as it has already been subjected to high temperatures during long periods, it has a great amount of free fatty acids and, as a result, demands lower costs associated with the saponification reaction. To evaluate the use of this residue as a reagent in phosphate ore flotation, the studied oil will be characterized in fatty acids composition by gas chromatography, and iodine, saponification and acid indices will also be determined. Batch flotation tests will be carried out varying collector dosages in order to verify the reagent efficiency and the obtained results will be correlated with the oil properties. This paper expects to demonstrate the use of this residue to produce an alternative collector, aiming the partial or total replacement of reagents currently used.

Oil shale presents an energy resource for the future. There are many occurrences of oil shale in the world such as in USA, Estonia, Jordan, Morocco, Australia, etc. All of those are of great economic importance in terms of alternative energy sources. Also, there is one great oil shale deposit in the Republic of Serbia near the town Aleksinac. The oil shale occurs in the Aleksinac coal mine basin, following the coal seams and spreads on 40 km2. The known reserves of oil shale in this deposit are estimated on 3,935,522,000 t with average oil contents from 9.5 to 12.5%. In this paper, the results on utilization of oil shale in cement industry directly and indirectly after burning them and after retorting them, i.e. In form of ash and in form of petrol coke will be presented.

The monitoring, evaluation and diagnosis of control loops have shown significant growth over the past few years. Considering that modern plants have hundreds of control loops, it is necessary to develop techniques that are able to monitor and evaluate these loops continuously in order to select those that would result in greater economic returns if properly tuned. In modern industries, it is common to use advanced control strategies and expert systems for production optimization. Through these systems, it is possible to determine the optimal set point for the control loops, to ensure the highest production rate by spending the least possible inputs and performing the whole operation with safety and quality. However, most of these optimization systems determines the set point for the SISO (Single Input, Single Output) PID control loop. Thus, the regulatory PID control is essential to ensure the stability of the system, following the set point determined with the best possible performance. However, it is noted that often the PID controllers do not exhibit adequate performance to ensure high performance necessary for the control systems. In the processing of minerals, the step of reducing the ore to the corresponding metallic state is executed in reduction furnaces. These ovens require strict control of its operating temperature, and are used for this control strategy applied to conventional combustion chambers associated with an advanced control system to optimize the operation. The control loop in question operates by manipulating the flow rates of air and fuel oil fed to the reduction furnace to ensure incomplete combustion with the formation of a reducing atmosphere (rich in carbon monoxide) and controlling its temperature. The present contribution proposes a semi-empirical mathematical modeling of the reduction furnace temperature. The obtained model refers to operating under typical conditions and was validated against experimental data collected during the production process. This model was implemented in the database of advanced control system and operated in conjunction with the digital control for distributed real-time execution. Subsequently, the model was implemented in MATLAB to study the influence of variations in the flow of fuel oil in the core temperature of the furnace. The preliminary results obtained using statistical analysis, demonstrate a significant improvement in the equipment performance.

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