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By Leming Ou, Hongqiang Li, Li Zeng, Qiming Feng, Yiping Lu, Guofan Zhang

"The entrainment of sericite, especially in the presence of hydrophobic microcrystalline graphite, leads to the poor flotation selectivity of microcrystalline graphite ore. In this paper, it was attempted to reduce entrainment of sericite, selective flocculation of microcrystalline graphite using polyethylene oxide (PEO) was studied. For the sake of flocculate microcrystalline graphiteselectively, flocculation tests of microcrystalline graphite and sericite single mineral were conducted.To investigate the effect of selectiveflocculation of graphite on entrainment of sericite in microcrystalline graphite flotation, batch flotation tests of graphite single mineral and artificial mixtures were conducted; theflocculationselectivity of PEO of different molecular weight (M.W.) was alsocompared inartificial mixture flotation. Inthe end, the structure of flocs in different particle size was studied by sieve analysis and microscopic observation. The resultsindicated that PEO of molecular weightone million andtwo million could selectivelyflocculate the microcrystalline graphite and reduce the entrainment of sericite at a lower dosage; further increasingof the dosage of PEO(M.W. ?two million) led to hetero-flocculation between graphite and sericiteandmadethe ash content of concentrate increase again."

Jan 1, 2014

By N. D. Ilankoon

"The use of thiosulfate as an alternative lixiviant for cyanide to treat complex refractory ores followed by the use of ion exchange resins (IX resins) for gold recovery has become an industrial reality. In this study, polyethylenimine (PEI) coated iron oxide magnetic nanoparticles (MNPs) were used to recover gold from the leaching solutions that consist of calcium thiosulfate, copper and gold. The gold loaded MNPs were easily separated from the solution using an external magnetic field. Proposing a novel adsorbent with characteristically easy solid-liquid separation, to recover gold from synthetic thiosulfate leaching solutions and gold elution and reuse of MNPs were the main objectives of this study. Adsorption isotherm studies revealed that the data fitted both Langmuir and Freundlich isotherm models equally well. The maximum adsorption capacity was 18.5 mg/g at pH 8 and 50?C. According to thermodynamic studies the physisorption process was exothermic and spontaneous. Gold and copper elution, and the regeneration and reuse of the nanoparticles were investigated and promising results were obtained. Different elution systems comprising sulfites, chlorides, glycine, EDTA (ethylenediaminetetraacetic acid) and sodium hydroxide were considered. Among them, EDTA for copper elution and NaOH for gold elution were the most efficient eluants. Regeneration and reuse studies revealed that the MNPs can be used for several cycles without significant performance loss. INTRODUCTION Although cyanidation has been used for gold leaching for more than 100 years, some major drawbacks associated with cyanidation have led to a quest for alternative lixiviants for gold leaching. Cyanide is ineffective in treating carbonaceous refractory ores as gold cyanide complex is adsorbed onto the native carbon in the ore itself known as preg-robbing. On the other hand environmental concerns associated with cyanidation drives the need for environmental friendly alternatives for cyanide. As of today, thiosulfate is known to be the most extensively studied and most promising alternative lixiviant for cyanide in both technical and environmental perspectives (Aylmore and Muir 2001, Oraby 2009)."

Jan 1, 2018

By R. A. Kleiv, H. Havskjold, N. Church, T. Malvik, M. Tro, E. Larsen

Liberation is one of the major purposes of comminution in mineral processing. In the simplest form, two or more minerals are present in a particle and have to be reduced such that the individual particles contain only one mineral. The complexity of the mineral intergrowth varies from ore to ore. Poor magnetic separation of iron ore may have many causes. In this paper, the emphasis is given to the problem of fine magnetite inclusions in quartz or other gangue minerals. This is highlighted by two Norwegian cases: one on a magnetite ore and the other on a hematite/magnetite ore. The inclusions in question are so small that they are not liberated by reasonable grinding. In both cases, the result has been either poor recovery or lower grade concentrates than desired. The first example concerns production of direct reduction concentrates from magnetite. Magnetic inclusions in gangue particles will be magnetized enough for the particles to pass into the concentrate. The second example is given a more detailed study, where the problem is caused by silicates with small inclusions of magnetite in a combined LIMS and WHIMS separation. This study included microscopy, Davies tube testing, and magnetization measurements. In particular, large gangue particles with magnetite inclusions were shown to have a tendency to bypass the LIMS separators as drag forces in presence of hematite are large. Such particles will then be picked up by the WHIMS as their magnetization is higher than for hematite. This was demonstrated by Davies tube tests, which indicated that such particles were picked up in preference to hematite particles. However, the Davies results did not give a good quantification. Magnetization measurements of gangue particles with magnetite inclusions was shown to be a better tool to quantify the magnitude of the effect of magnetite inclusions in magnetic separation.

Jan 1, 2018

By Rong Fan, Roger Smart, Ning Xu

As part of an Australian Research Council project with Newmont and Newcrest mining companies studying the influence of clay minerals on rheology, hydrodynamics and flotation response, the cryo-SEM technique has been used to capture and image the clay (low crystallinity kaolinite Q38) aggregate structures in the flotation pulp immediately after collector and before frother addition. Samples were also collected from the earliest froth phase and the froth overflow corresponding to early and later concentrates. In this technique, a copper tube is filled with the sample during operation of the cell. The tube is immediately plunged into liquid nitrogen vitrifying the water phase before it can crystallise as ice thereby retaining the structures without volume or other physical change. After sublimation of the vitrified water surface, the aggregate structures are revealed and can be compared between pulp and froth phases from clays in different feeds and flotation conditions. The images from both low-clay ore and ore with clay content reveal various levels of aggregation as predominantly edge-edge connected aggregates similar to those found in our previous studies of high-clay tailings. For the samples from the ore with clay content, more extensive edge-edge clay strings are found in the early froth phase as compared to exiting froth overflow and the pulp phase with short edge-edge connected strings. It is suggested that the strings of clay particles result from edge-edge aggregation in the Plateau borders of the bubbles before breakage during sampling and the more extensive edge-edge aggregation in early froth phase is induced by crowding in the bubble borders. The clay strings collected into the overflow concentrate are almost all broken up compared with the Froth before drop-back. The implications for entrainment and entrapment mechanisms of gangue capture in froth will be discussed.

Jan 1, 2014

By Paul W. Weiblen, Louis J. Cabri, Rolando Lastra

"Preliminary tests were done to determine whether comminution by electric-pulse disaggregation, or E-PD (cf. Rudashevsky et al; 1995), was more effective than using conventional crushing for Merensky Reef ore. A hand sample of the Merensky Reef was sawn in two: then one sub-sample was comminuted to .2 mm using E-PD at the University of Minnesota, and the other sub-sample was crushed to .2 mm using a conventional jaw crusher at CANMET.The products of the electric-pulse disaggregation and jaw crusher were fractionated by sieving and by a separation using a heavy liquid with a specific gravity of 3.3, because the proportion of platinum-group minerals (PGM) and sulphides to silicate minerals is very low. Thus, four mineral separates were produced: .2000 + 833 µm, -833 +208 µm, -208-µm float and -208-µm sink. All the mineral separates were studied by image analysis (Lastra et al; 1998). The main objective was to determine the liberation of gangue (silicate minerals), chromite, pyrrhotite, chalcopyrite, pentlandite and PGM. In the case of the PGM, a specific image analysis program was written to search and measure these minerals.The results show that the liberation obtained for gangue was similar (~99%) using either method of comminution. However, the liberation obtained for chromite (~89% vs. ~38%), pentlandite (~50% vs. 1%), pyrrhotite (~56% vs. ~38%), and PGM (~56% vs. ~1%) by E-PD was higher than that obtained by conventional jaw crusher, whereas the liberation obtained for chalcopyrite (~20% vs. ~71%) by E-PD was lower. Nevertheless, the image analysis of the products also showed that the PGM are strongly associated with pentlandite. Thus, for the Merensky Reef, liberation of pentlandite from the gangue minerals and chromite is important to recover more of the PGM. This maybe be significant because, in addition to increased recovery of platinum-group minerals (PGM), Merensky Reef pentlandite also contains significant quantities of valuable platinum-group elements like Pd and Rh (Cabri, 1981; Cabri 1988, Kinloch 1982, Peyerl 1983). Hence, the results indicate that for the Merensky Reef, electric-pulse disaggregation would represent a better comminution operation than a conventional jaw crusher would. In addition, the greatly improved liberation for chromite may find application for the PGM-rich UG2 chromitite."

Jan 1, 2003

By Mario Gerards, Sergej Podkow, Marco Steinberg

"The JONES® WHIMS technology is based on the magnetic separation process and is widely used for the recovery of magnetically susceptible iron ore particles. The conventional machine design is well-known within the iron ore beneficiation industry for more than 50 years and recognized to be highly reliable, robust and extremely compact with the advantages of high capacity and selectivity. In 1981 Rana Gruber AS, Norway bought 14 JONES® WHIMS DP 317 separators when the magnetic separation plant was built and erected. Today, 11 of these old machines are still operating profitably and efficiently. The former supplier was the coal and minerals division of Klöckner-Humboldt-Deutz (KHD) which is today MBE Coal & Minerals Technology GmbH (MBE). This paper outlines a detailed description of the project of revamping the above mentioned old machines and describes the challenge of incorporating enhanced and newly developed technology into an existing processing plant. Further it gives an overview of the recent developments on the design of the JONES® WHIMS. In order to meet modern product requirements and to increase and secure plant productivity, in 2012 Rana Gruber AS settled a contract covering two new designed JONES® WHIMS DP 317 HFR separators to be implemented into the existing building and the upgrading of all 11 older JONES® WHIMS under the use of as many refurbished items as possible. The two new machines were fully developed by the product specialists of the supplier in cooperation with the operator Rana Gruber AS, thereby taking advantage of their great experience. The design of the new machine is based on the conventional design, i.e. the general operating mode as well as the overall dimensions are identical. Finally this paper gives an overview about the erection and commission phase of the two new machines and gives a detailed comparison between conventional and enhanced WHIMS technology."

Jan 1, 2014

By P. C. Beuria

Iron ore concentrate contains different mineral phases viz. hematite, magnetite, goethite, kaolinite, and gibbsite. Presence of some of these phases like goethite, kaolinite, and gibbsite contribute to the loss on ignition (LOI) content of the sample. Iron ore fines (pellet feed) are pelletized for utilization in DRI & BF processes. In the present pelletization technology i.e., straight grate and grate kiln processes, the LOI in the ore should be within the range of 2.0-2.5%. LOI content in the iron ore concentrate is found to be more than 4% after beneficiation of low-grade iron ore. It is therefore difficult to produce good quality pellet because of high LOI content. The LOI content of the sample is a detrimental factor in the pellet making. For effective pelletization, the LOI content in iron ore fines needs to be reduced before pelletization. It can be reduced by fluidized bed roasting. The objective of present work is to understand the kinetics of removal of LOI from iron ore fines. The effects of bed depth, temperature, and residence time on reduction of LOI content in iron ore fines were studied using muffle furnace. The process of roasting was carried out at four different temperatures varying from 400 to 950 °C with a variable residence time of 30, 45, 60 & 75 minutes and at bed depths of 16, 32, 48 & 64 mm. In all instance of experiments carried out, one of the parameters was kept constant. It was observed that at 850 °C and 30 minutes of residence time, there was sufficient removal of LOI in static bed condition even at a high bed depth of 64 mm. Keywords: LOI, pellet feed, fluidized bed roasting, goethite

Sep 1, 2012

By T. N. Matveeva, T. A. Ivanova

"The article presents the results of the research aimed at development and testing of new effective reagents – collectors and green modifiers for more complete extraction of gold and platinum to concentrates at reduced loss with waste products. The main deposits of Au and PGM ores of Russia and abroad are presented by refractory raw material with the non-uniform finely-interspersed sulfide mineralization, submicron gold and platinum, the low metal content, non-uniform distribution of valuable minerals. and show low indicators of recovery. The main losses of precious metals (up to 15 %) at flotation are associated with thin slam tailings because of inefficiency of standard reagent modes.In the paper, the new trends in design of collecting agents for extraction of gold and PGM sulfide minerals and their application in flotation tests are substantiated. The original technique for obtaining the modified collector reagents – dithiocarbamate, dithiophoshpinate and dithiazine, incorporated non-ionic compounds that are able to generate stable complexes with gold and platinum has been developed. A novel class of collectors – cloud point polymers showed high flotation recovery of fine particles of gold and platinum. The original technique to create the mineral samples of natural sulfides with ""invisible"" or sub-micron gold on their surface designed helped to indicate the mechanism of selective adsorption of novel agents on Au and Pt-sulfide minerals. Extractive UV spectrophotometry, potential measurements, X-ray phase and spectral analysis, scanning electronic microscopy (SEAM), laser SIM and AFM microscopy were applied to analyze the adsorbed layer of modified reagents on the mineral surface. Selective hydrophobic covering on the surface of micro- and nanoparticles of noble metals provided an increase in their extraction during flotation. New reagent modes of modified collectors and green modifiers were tested in scaled-up laboratory flotation and the results obtained demonstrated the increased quality of the concentrates in terms of gold content by 1.5 times and higher gold recovery by 1.5-5%. The studies have been supported by Grants of the President of RF “Scientific School of Academician Chanturiya” NSh-220.2012.5; NSh-748.2014.5."

Jan 1, 2018

By Tchingis Lekhatinov, Lev Filippov, Vyacheslav Severov, Alexandre Matinin, Victor Samyguin, Inna Filippova

"Comparison of flotation efficiency of the new multi-zone flotation cell (MZFC) and different conventional cells was carried out at lab and pilot scales on the various samples: high contrast pyrite tailings and old copper containing tailings. MZFC is a cell of intensive flotation, which provides optimal hydrodynamic conditions for all flotation sub processes. Enhancing of particle attachment, creation of conditions for coalescent flotation, selection of spatially separated zones according to optimal hydrodynamic conditions for flotation sub-processes are proposed as main principles to design an MZFC. The bubbles/pulp stratification was pointed out as a limiting step in the existing intensive flotation machines. Two strategies to improve bubbles/pulp stratification in the MZFC were studied: (a) impact of pulp-bubble jet to the surface of a prismatic insert inside of cell, which provides the detachment of low hydrophobic particles from bubbles, and (b) profiling the pulp/bubbles jet from the reactors due to a specific geometry of cell walls. The new continuous MZFC devices were demonstrated similar or higher efficiency in comparison with laboratory batch flotation cells for pyrite flotation. Higher flotation efficiency (82%) with pure pyrite concentrate (51.2% of sulfur) and a recovery level of 92% was obtained in MZFC when the cell with stratification by impact was used. Similar results were obtained with old Cu-containing tailings. Although MZFC had 1.5 times greater yields of concentrate than a batch flotation cell, it provided the increase of chalcopyrite recovery by 29.4% and concentrate grade by 4.8%. An original organization of pulp/bubbles stratification in the separator part of the new intensive flotation machine using variable geometry inserts allowed the best flotation selectivity with a bubble mineral loading coefficient 1.5 fold higher than the laboratory mechanical or pilot cells."

Jan 1, 2014

By A. V. Golovanov, A. V. Mihailova

"NPO RIVS employs complex approach to engineering and design of the new facilities in close cooperation of Mining, Research, Hydrometallurgy, Design, Construction, Power Supply, Automation, Production and other departments. General Design Contractor (and then General Contractor) is directly involved in geological exploration, engineering surveys, floatability studies, feasibility study of process solutions and construction options. It delivers greenfield project and guarantee its efficient performance in future. Shiralgin is a small gold and copper deposit, gold average grade is 4.7 g/t. RIVS departments have studied ore floatability, developed process procedures for design and performed pilot testing. Construction of integrated plant including ore crushing and grinding, flotation and hydrometallurgy units with Dore gold production of 5 000 thousand tons ore per year (66.7 t/h) is recognized as economically viable. The technology used of separate dry stockpiling of flotation tailings and cyanidation tailings. Water circuit for concentration and hydrometallurgy is separated, too. Process design was performed based on BIM software like Autodesk Revit, Civil 3D, Rocscience slide using process procedures developed by RIVS Research units. Engineers provided modeling of primary crushing unit, coarse ore storage, main building (including grinding, flotation, thickening, filtration, loading, hydrometallurgy), tailings thickening unit, building for reagent storage and conditioning, tailings pond for dry stockpiling of flotation tailings and cyanidation tailings, sedimentation ponds, laboratories, infrastructure including Administration building and camp. Payback period is 3.5 years. 3D model of facility is currently stored at the State Agency of Geology and Mineral Resources affiliated to the Government of the Kyrgyz Republic.INTRODUCTION The Kyrgyz Republic has substantial potential of mineral resources including gold ores. Mining industry actively develops and involves international investors. Inventory includes 42 deposits (Figure 1) that have reserves of 616.4 t [1] of gold. The Kyrgyz Republic takes the third place in gold mining among CIS countries after Russia and Uzbekistan by producing up to 20 t annually."

Jan 1, 2018

By Matveyeva Tamara

The main deposits of gold-sulfide ores of Russia are characterized as refractory raw material with the non-uniform finely-interspersed sulfide mineralization, submicron gold, the low gold content (3-5 ppm) and non-uniform distribution of the gold associated with pyrite and arsenopyrite. These ores show low indicators of extraction of gold and silver at cyanidation. Flotation is one of the basic technological procedures of processing of gold sulfide ores however simultaneous presence of pyrite and arsenopyrite and lack of effective methods of their selection constrains application possibility of flotation schemes because of rigid requirements to flotation concentrates under the arsenic content and practically excludes smelting of pyrite concentrate. The main losses of precious metals at flotation technologically are concentrated in thin classes (up to 15 %) demonstrating an inefficiency of standard reagent modes. For an estimation of expediency and possibility of application of selective flotation of pyrite and arsenopyrite a scientific substantiation of the mechanism and criteria of selection of gold-bearing ferrous sulfides of various material structure is developed and for difficultly divided pairs of sulfides with close technological properties the new selective reagents providing effective extraction of gold from hard-to-beneficiate ores are designed. The original technique for modifying surface composition of natural sulfides by nano-sized Au is worked out and the mechanism of selective adsorption of new reagents ? oxypropyl ester of diethyl-dithiocarbamatic acid (OPDTC) and oak bark extract (OBE) on Au-bearing sulfide minerals is revealed. Formation of almost insoluble OPDTC-Au compounds is defined by methods of scanning electronic microscopy (SEM) and UV-spectroscopy. Application of developed reagent modes using new reagents have been tested in laboratory conditions at flotation gold-sulfide ores samples and collective concentrate probes providing high extraction of gold and improved quality of the concentrate (less than 2 % As). Keywords: pyrite, arsenopyrite, selective flotation, flotation reagents adsorption, complex-forming, gold recovery.

Sep 1, 2012

By N. Panteleeva, E. Konoplev, I. Michailova, S. Titkov, S. Aliferova, T. Gurkova, T. Chumakova

Cationic flotation using alkylamines and their derivatives as collectors, and characterized by high selectivity of mineral particle separation, is finding ever growing industrial application. In recent years the industrial application has been initiated of new cationic collectors - alkylmorpholines. Efficiency of cationic surfactants operation as collectors is dependent upon their colloid and sorption properties and the availability of silicate .carbonate rock-forming mineral impurities in the ore, which sorb the cationic collector. Investigations have been carried out on the influence of frothers and organic depressors with various compositions upon physical-chemical and flotation properties of alkylamines and alkylmorpholines. On the basis of these investigations requirements for organic depressor were developed and new flotation reagents were proposed (V-1 frother and KS-MF depressor). The use of new reagents enables one to decrease considerably the consumption of expensive cationic collectors and to enhance the floatability of coarse mineral particles. Data of new reagents industrial application is presented. The reagents developed can be used for flotation processing of other ores.

Jan 1, 2003

By N. Pradhan

In the Sukinda valley, Orissa, India, a large quantity of overburden material is generated during the mining of chromite mineral (on average 10 tons for every ton of ore). The overburden hereby depicted as ?lateritic nickel ore? contains on an average 0.5% Ni. IMMT Bhubaneswar is working on this material for extraction of nickel and cobalt. But for better recovery of metal values, thermal activation or thermal reduction of ore is required. An alternative biotechnological route for reduction of ore is hereby attempted. An anaerobic dissimilatory Iron (III) reducing bacterial consortium (here denoted as IRB), capable of imparting iron phase changes in the lateritic nickel ore was established which improves the subsequent extraction of co-precipitated Co (III) and Ni (II) from the ore. In this study, properties of thermally and microbially reduced lateritic nickel ore are compared vis-à-vis original ore. Due to the phase changes, original light brown color of the lateritic nickel ore changes to dark brown on IRB treatment. This dissimilatory reduction of ore leads to formation of some magnetic particles, which were separable by hand held magnet. Roasting and IRB treated ore on acid leaching with H2SO4 show about 45 % and 36 % leaching of nickel ore compared to about 18 % leaching from the original lateritic ore. If bacterial reduction method is successful, cost intensive method of ore roasting process can be eliminated. Thus, it is possible to make use of dissimilatory iron reducing bacteria for recovery of valuable metals from off grade iron ore/ laterites. Keywords: lateritic nickel ore, bacterial reduction, thermal reduction, dissimilatory fe (iii) reducing bacteria

Sep 1, 2012

By Junji Shibata

In a present process to treat the tungsten carbide tool waste, the wastes are roasted in air and then an alkali leaching is carried out in an autoclave. An environmentally friendly process is required to recover rare metals (Co and W) from the wastes. The effect of mechano-chemical (MC) treatment on leaching of rare metals was investigated in this study. The solvent extraction and crystallization-stripping methods were applied to separate and recover tungsten and cobalt in the leached solutions. The MC treatment for the rare metal leaching is effective to dissolve rare metals from the wastes due to the change in crystalline structure of WC and oxidation of WC with KMnO4. Cobalt ions are extracted with D2EHPA by a cation exchange reaction. Tungsten in the leachate can be extracted by TOA (tri-octyl amine) as an extractant, because tungsten species exist as a form of anionic species in acidic solution. The rare metals in organic phase are recovered as insoluble salts such as oxalates and ammonium salts in the crystallization-stripping process. Keywords:unheated oxidation, solvent extraction, crystallization-stripping, recycling

Sep 1, 2012

By S. K. Chaurasiya

o meet the ever increasing demand of iron oxide feed stock for rapidly growing domestic steel industries and to effectively manage the depleting reserve of high grade lumpy iron ore, Pelletization of iron ore fines/slimes are expected to play a dominant role in the near future. Use of pellets will also enable the blast furnace operator to achieve higher levels of productivity with lowering of operating cost. The effective utilization of Iron Ore Slimes is important not only from the point of view of optimum utilization of Iron values in the mined ore but also for preventing environmental pollution. A significant amount of slime is being accumulated at the tailing dam of one of the iron ore mines and with the present scale of operation the tailing dam will be filled in another 10 years. Hence to increase the life of tailing dam and for better utilization of the iron values a study has been carried out for the suitability of pellet manufacturing with slimes and fines at our laboratory. The pelletization studies are aimed for optimization of various parameters for production of Blast furnace/ DR grade pellets from beneficiated slimes and Fines. This paper attempts to describe the production of blast furnace grade pellets from beneficiated slime and fines and its characterizations.

Sep 1, 2012

By Josefin Lannefors, Anders Klingberg, Natalija Gorochovceva

"Development of new anionic collectors becomes more and more important. This can be explained, on the one hand, by the fact that over the years phosphate ores have become more fine grained and complex (example weathered). On the other hand, a development with a focus on sustainability (sustainable development) of new anionic surfactants is required by authorities and society. Within the sustainable development several characteristics of a collector have to be taken into an account: efficiency, selectivity, froth characteristics, environmental profile, raw materials used for the synthesis, manufacturing complexity, stability upon storage, etc.Several anionic surfactants based on ester and amide chemistry were synthesized, characterized and used as flotation agents for calcium phosphate containing ore. The surfactants were used in a formulation together with other anionics, since in a pure form, during the flotation, they did not provide right froth characteristics.A new anionic collector/formulation was developed, that fulfills all above listed requirements."

Jan 1, 2014

By M. Saghaeian, R. Hejazi, L. Hosseini, M. Zare

Difference between plant feed specifications in practice and design feed is a problem that most of processing plants face during operating and commissioning. This topic has led to inappropriate operating and necessitates repeating the basic tests on new feed. Gol-E-Gohar fourth concentrate line with a capacity of 2 MTPY, located in Kerman province, is the first iron concentrate plant in Iran in which High Pressure Grinding Roll (HPGR) technology has been applied. Plant&apos;s feed consists of 30% AG mills pebbles of lines 1-3 and 70% run of mine crushed ore whose Fe=51%, Fe/FeO=2.5, S=1.7% and work index=15 kWh/t. Desired concentrate has Fe>68% and S<0.7%. After the plant construction and operation commencement, providing design feed was not possible due to the crushing unit`s not being complete, therefore the plant was fed by AG mills pebbles. For predicting optimal conditions of the plant and investigating the possibility of improving the current concentrate specifications, sampling from the new feed and laboratory and pilot tests was performed again. Studies showed that new feed has Fe=41%, Fe/FeO=3.5, work index=17 kWh/t. Results of laboratory tests with Davis tube device and pilot tests run using magnetic separators with simulating the plant`s circuit showed that with current feed, achievable recovery in industrial scale would be 75.52% which compared to plant&apos;s recovery in studied period (75.94%) shows that plant operated in optimal conditions. To improve the current concentrate specifications (Fe=66%, S=1.03%, Ferec=75.94%) and for achieving desired concentrate, samples were reground to four fractions with k100= 300, 212, 100, 45 and Davis tube tests were performed on each of the samples separately. Results showed that the fraction whose k100=212 µm or k80=200 µm has respective Fe and S grades of 68.27% and 0.681% which are consistent with the desired concentrate.

Jan 1, 2014

By Vladimir F. Skorokhodov, Nikolay N. Melnikov, Svetlana P. Mesyats

"Among the problems of the civilization development, a problem of interaction between man and natural environment can be highlighted. In the twentieth century the human transforming activity had got scales of geological processes and defined the contradiction between the goal to increase the quality of human life and possibilities of the natural environment. Last twenty-five years after the World Summit on the Environment (1992) indicate that the development of civilization is still based on receiving super profits from the natural resources exploitation. This statement is confirmed by economy globalization rates, growing contradictions between consumption and production, depletion and degradation natural environment. A new technological order is formed at the time of growing world population, technological capacities, organizational complexity, from one side, and global scales of geo-resources consumption, on the other side. Sciences, determining the further civilization development, should take on the task to change the social worldview, since the preservation of human population consists in remediating and maintenance of biosphere functions as a regulator of ecological balance. The new worldview in the geo-resources exploitation is based on the Ecological strategy of mining development, which consists in reducing mining-induced loading on natural environment while increasing efficient mineral production and processing, and providing for a comprehensive solution of tasks on mineral deposit development. One of strategic trend of mining development is to increase complexity and completeness of useful component extraction from ore and mining deposits while reducing wastes and decreasing their stockpiled volumes. The implementation of the ecological strategy has shown that the future is determined by reduction of the environmental impact while improving the efficiency of mineral mining and processing.INTRODUCTION The global nature of environmental problems caused by the scale of consumption of natural resources, huge amounts of waste, and intensive man-made impact on the environment requires a revision of the strategy for the natural resources development. Many existing technologies are ineffective in achieving the ultimate goal. Direct output in the raw materials - the end product technological chain rarely exceeds 10%, which implies a huge amount of work to move the soil. In addition, the feature of scientific and technological progress at the present stage is the growth of power-to-weight ratio."

Jan 1, 2018

By Sirish L. Shah

It is now common to have archival history of thousands of sensors sampled every second over long time. Yet we frequently have process engineers complain:??.We are drowning in data but starving for information??. How can these rich data sets be put to use? This paper addresses the issue of information and knowledge extraction from data with emphasis on process and performance monitoring including fault detection and isolation. Most of the major plant, factory, process, equipment and tool disruptions are avoidable, and yet preventable fault detection and diagnosis strategies are not the norm in most industries. It is not uncommon to see simple and preventable faults disrupt the operation of an entire integrated manufacturing facility. For example, faults such as malfunctioning sensors or actuators, inoperative alarm systems, poor controller tuning or configuration can render the most sophisticated control systems useless. Such disruptions can cost in the excess of $1 million per day and on the average they rob the plant of 7% of its annual capacity. Over the last decade the fields of multivariate statistics and data visualization and analysis methods have merged to develop powerful sensing and condition-based monitoring systems for predictive fault detection and diagnosis.These methods rely on the notion of sensor fusion whereby data from many sensors or units are combined with process information, such as physical connectivity of process units, to give a holistic picture of health of an integrated plant. Such methods are at a stage where these strategies are being implemented for off-line and on-line deployment. This article attempts to outline the field of sensor fusion - the application of signal processing methods, in the temporal as well as spectral domains, on a multitude and NOT singular sensor signals to detect incipient process abnormality before a catastrophic breakdown is likely to occur Keywords: Process analytics, process and performance monitoring, multivariate statistical analysis, sensor-fusion

Sep 1, 2012

The simulation study on the process of iron ore beneficiation plant of Essar Steel, Kirandul was carried out. The iron ore fines and slimes generated nearby Bailadila mines of NMDC are used as raw materials for this beneficiation plant. The capacity of the plant is 1400 TPH operating in parallel in two streams. The capacity of the plant was utilized about 60% of throughput capacity. To improve the plant capacity as well as quality performance, the simulation study was conducted to detect the bottleneck of the process. The process samples were collected from input and output of each processing unit operation to generate the data base for simulation study at the feed rate of 400 and 500 TPH of iron ore fines in a single stream. The characteristics data i.e., breakage and selection functions were generated using MILLSOFT package for simulation of ball mills. Then MODSIM package was used to evaluate the performance of each unit operation to identify the bottleneck. It was established by a simulation study that the intermediate thickener draws high current when the feed rate is more than 400 TPH due to high torque drawn by rotating rake because of presence of coarse particles in the input stream to thickener. The problem was sorted out by classification of input stream of thickener to remove the coarse particles. Then the process was simulated at its rated capacity, and experimental validation studies at the plant were also conducted at the feed capacity of 600 and 700 TPH by modification of process flowsheet. The experimental data was almost matching with simulated data. Finally, the processing plant is running with full rated capacity without any bottleneck. Keywords: simulation of ball mill, breakage function, selection function, iron ore

Sep 1, 2012