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By Alex Heath, Andrew Barycki, Baladron. Javier

"Efficient flocculation is important to thickener performance, affecting the overflow clarity, solids settling flux, underflow density and operability. Many factors affect flocculation; from the material/flocculant type, dilution of the feed and flocculant solution, mixing, to the shear rate and shear history. The flocculant addition point (or points) can be used as a tuning method to alter the effective flocculation time in a feedwell, with addition further up the feed pipe increasing the residence time but making the aggregates more prone to breakup if they experience high shear later in the process. Conversely, adding the flocculant later, eg under the feedwell shelf decreases the mixing time but allows some free (unadsorbed) flocculant to be available at the feedwell exit. An extensive trial has been performed on an operating thickener comparing seven individual different flocculant dosing positions through a Vane feedwell, and some combinations of two dosing points simultaneously. Measurements of the velocity, solids concentration and aggregate size were made throughout the feedwell at the different positions, with the dosing points significantly changing the aggregate size and clarity, and also affecting the solids concentration at some positions. The results are accessed in terms of flocculation kinetics and used as CFD validation data."

Jan 1, 2014

By Sergey Ulianov, Arkady Senchenko, Alexey Shvets, Arkady Bakotin

"This paper contains description of research results of technology development for copper recovery from weathered tails of iron processing plant. The predominant host mineral that contains valuable component is chalcopyrite occurring in its free form and in associations with ore and rock-forming minerals. Copper grade is 0.26-0.30%. Emulsion inclusions of chalcopyrite in pyrite and sphalerite were noted. Major problem is low copper recovery (30-35%) by flotation. When studying chalcopyrite in primary concentrate it was determined that the surfaces of many chalcopyrite grains are covered with oxide films which prevented collector attachment onto them. Second issue was deep association of chalcopyrite with pyrite and sphalerite. Sulfidizing reagent addition did not help to reach the required level of copper recovery to concentrate. In the result of research performed the technological flowsheet was developed including preliminary treatment of head material in a special unit aiming at oxide films removal, followed by copper rougher flotation on head size tails, crude concentrate regrinding and a number of cleaner flotation operations. After the treatment of weathered tails according to the flowsheet developed, copper recovery to flotation concentrate became 71.53%, at 23.46% copper grade. The suggested technology allows one to solve the issue with treatment of technology-related copper-containing stockpile material, as well as to include the ores where copper is represented by sulfide minerals covered with oxide films into processing."

Jan 1, 2014

By Liu Xinghua

Yuanjiacun iron ore located in Shanxi province of China has finely disseminated grain size and contains refractory iron-bearing silicate gangue minerals such as chlorite. Therefore, a large amount of secondary slime (the content of -10µm fraction was up to 32.92%) was produced inevitably in fine grinding process, and chlorite was also enriched in concentrate from the content of 4.3% to 14.8% after high intensity magnetic separation. These two characteristics result in the difficulty to deal with Yuanjiacun iron ore by flotation. In this test work, contrast tests between single reverse flotation and selective flocculation desliming-reverse flotation were conducted on Yuanjiacun iron ore. The test results show that after selective flocculation desliming, the iron grade of cationic reverse flotation concentrate increases by 6.15% and the recovery increases by 7.25%; the iron grade of anionic reverse flotation concentrate also increases by 2.15%. Furthermore, analyses of grain size composition and mineral composition were carried out on separation products, the results indicate that selective flocculation desliming plays a dual role of optimizing grain size composition of flotation feed and removing iron-bearing silicate gangue minerals (chlorite) effectively.

Sep 1, 2012

By N. Dhawan

In the last decades, High Pressure Grinding Roll (HPGR) has gained significant importance in hard rock processing due to numerous metallurgical benefits such as energy savings, particle weakening, preferential damage of coarse particles, and preferential comminution-liberation. There are a limited numbers of lab-scale HPGR units throughout the world. The laboratory-scale HPGR machine at the University of Utah is first-ever lab-scale machine designed by late Dr Klaus Schönert, the inventor of HPGR. This HPGR is constructed with two counter-rotating hardened tool steel rolls, each 200 mm in diameter and 100 mm in width. The HPGR unit is equipped with eight sensors and a robust control system, which serves as an ideal system for fundamental studies and lab-scale testing. In HPGR operation, throughput, energy and product size distribution are intricately linked to specific grinding pressure, roll gap and rolls speed. The nip angle existing during the operation determines the volume of feed material above the rolls that is pulled into rolls without slip. In this paper, scale-up factors and some of the existing models have been reviewed. A number of experiments have been carried out with limestone and a slag material. The influence of operating variables and their complex relationship has been studied.

Sep 1, 2012

By Tamara Matveyeva, Tatiana Ivanova, Nadezhda Gromova

"The paper presents the results of study of the sorption and flotation properties of the reagents of plant origin - tannin and natural extracts of the oak bark and stems of plants, with a view to their application as a low-cost environmentally friendly modifiers of iron sulfide flotation for the recovery of minerals containing precious metals. The technique of preparation of plant extracts with a fixed content of extractable tannins has been developed.The mechanism of flotation reaction of tannin extracts has been identified as based on their adsorption on the surface of pyrrhotite and arsenopyrite to form strong complexes with iron (III) at concentrations below micelle concentration. It has been found that adsorption of plant extracts occurs without displacement of primarily adsorbed xanthate, and preliminary adsorption of xanthate did not preclude fixation of tannin on the mineral surface.It has been shown that plant extracts having hydrophilizing properties at low concentrations could be applied as selective depressants for pyrite, pyrrhotite and arsenopyrite in a weakly acidic, neutral or weakly alkaline medium. The use of plant modifiers could help to increase the quality of gold- and platinumcontaining concentrates and reduce the ecological impact on the environment."

Jan 1, 2014

By P. Fawell, C. Castillo, C. Ihle

"The need to reduce fresh water consumption has pushed many Chilean mining companies to utilize seawater obtained from distant locations. At the same time, increasing amounts of fine particles in copper tailings raise new operational challenges, in particular, the thickening and transport of tailings featuring significant fine fractions, which are predominantly clays. In the present paper, we study the role of salinity – using seawater and NaCl – on the flocculation efficiency of copper sulphide tailings to which kaolinite was added. To mimic the water recovery stage in thickeners, flocculation has been induced in jar tests and the corresponding aggregate size distribution has been estimated from chord length distribution data obtained using a focused beam reflectance measurement (FBRM) probe, at various mean turbulence intensities. Results show that for constant flocculant dosing, a measurable influence of the salt on the resulting aggregation exists. For each case, resulting optimal turbulence levels are also reported, a particularly interesting feature when comparing flocculation efficiency of the coarse and fine fraction. INTRODUCTION The concentration of copper minerals through comminution and flotation is intensive in the use of fresh water. The need to reduce the consumption of fresh water and the environmental standards associated with increasingly demanding mining operations have driven improvements in the techniques of recovering water from tailings. The challenges are even greater when required to treat minerals with high clay contents. In Chile, kaolinite is one of the most important clays to consider due to its abundance in the tailings from many operations. The most common and highest throughput unit operation in the mining industry for the recovery of water from tailings is gravity thickening, with sedimentation of fine particles assisted by flocculation. Flocculation is the process of forming aggregates by contacting the suspended particles with a flocculant. The flocculant is typically a water-soluble synthetic long-chain polymer, where copolymers of acrylamide and sodium acrylate are the most common types used in the Chilean mining industry. The aggregation mechanism includes the following key steps: (1) flocculant distribution through the suspended particles, (2) flocculant adsorption onto particle surfaces, and (3) collisions between particles leading to polymer bridging to form aggregates, but concurrently (4) breakage of aggregates becomes a factor under prolonged shear (Gregory, 1988)."

Jan 1, 2018

By M. Holuszko, I. Mikhalev

"Previous studies described by Galvin et al. (2017) have shown that for Australian bituminous coal fines, both in batch and in continuous process, the new improved oil agglomeration procedure based on the use of high-internal-phase (HIP) emulsions, as compared to the conventional “pure oil” agglomeration process, enables a significant reduction in the amount of oil while reaching a high yield of clean coal (approximately 90% of agglomerates greater than 355 µm in size) in a significantly shorter time. The HIP emulsion used in these experiments comprised up to 95% vol. aqueous solution of sodium chloride (3% wt. concentration) and for the rest, a mixture of kerosene (oil) and sorbitan monooleate (SMO emulsifier) in a 1:1 ratio as a binder. This study evaluates the applicability of the new HIP-oil agglomeration process to treat Canadian bituminous ultra-fine coal and Russian sub-bituminous coal fines and compares results from agglomeration to the flotation response of both coals. Oil agglomeration is known to be sensitive to surface properties of coal. Since surface properties of coals depend not only on the rank of coal but also on their origin (depositional environment) and mineralogical composition, both the applicability of this new improved agglomeration process to the non-Australian coals and its efficiency became the motivation for this study. To evaluate the applicability of the new process to both Canadian bituminous and Russian sub-bituminous coals, a series of bench-scale tests were carried out under conditions similar to those described by van Netten et al. (2016) for the Australian coals. Based on the results obtained in this research, new boundary conditions for the application of the HIP emulsion-based oil agglomeration process have been outlined and conclusions on the viability of the new process to treat ultra-fine coal from Western Canada and Russian sub-bituminous coal fines have been reached.INTRODUCTION In most cases, to meet the market requirements, the mined coal has to be processed to reduce the ash content by the removal of mineral matter and thus to increase the quality of the coal products (van Netten et al., 2016). Generally, flotation is used for processing fines from high rank coals; however, there are high losses of very fine coal due to the inefficiency of this process. Furthermore, difficulty in dewatering the fine coal results in excessive moisture levels causing coal handleability issues, which increases costs in the coal-cleaning industry (Capes & Darcovich, 1984). Much of the development that has occurred in fine coal cleaning has taken place with higher-value coal, often metallurgical (Klima et al., 2012). If the fine coal is deemed to be too difficult or expensive to process, it may be discarded as waste (van Netten et al, 2014). Such disposal not only creates an environmental liability but may also result in the loss of a valuable, high quality product that is better liberated than the coarser fractions of coal."

Jan 1, 2018

By Mohan Ram

Structural impurities in the crystal lattice of rock phosphate of Indian origin is a great challenge for beneficiation and practically possesses remote scope of upgradation to the desired level for industrial utilization. There is a wide occurrence of rock phosphate in different parts of India with different characteristics viz. siliceous, carbonaceous and ferruginous. The structural cationic replacement in the composition of apatite is due to the exchangeable cations present in the external impurities associated with the rock phosphate ore. The Indian rock phosphate ore from Purulia district, West Bengal is characterized as unusual structural composition due to the exchangeable cation in its composition. The elemental distribution of ore exhibits the disproportionate ratio of P2O5 and CaO which is 5.88: 3.31 in reference to the theoretical composition of P2O5: CaO in apatite which is 4.23: 5.55. The substitution by trivalent Al+++ cations within the structure of apatite in place of divalent Ca++ is found upto 18% and substitution of exchangeable cation in place of PO4 and F ion by CO3/SO4 is found upto 0.1% and OH ions upto 0.2% respectively in a lattice of apatite thereby diluting the grade of rock phosphate and restricting its industrial use even after beneficiation. This paper reveals the unusual compositional features of rock phosphate under study and is a guideline to the mineral industries using such rock phosphate. Keywords: external impurities, exchangeable cation substitution, structural compositional features, electron probe micro analyzer

Sep 1, 2012

By L. Q. Luo

SHP-F3200 wet high-intensity magnetic separator (HIMS) was successfully used to separate the complex and weakly magnetic iron ores being composed of specularite, limonite and siderite in Ji-uquan Iron and Steel (Group) Co Ltd (JISCO). It is more and more difficult to separate iron ores from gangues, such as quartz, jasperite and phyllite, as the properties of iron ores gradually become more complicated and refractory. Some technologies have been used to improve SHP-F3200 HIMS, including modifying angle of magnetic polar from 90°to 83°, cooling exciting coils by oil instead of air, adding reverse-washing device to wash off magnetic particles, adjusting the tooth-space of matrix from 5.0 mm to 3.5 mm or 2.5 mm, so as to enhance the recovery of fine iron ore particles. It is still difficult to meet the requirement for recovering more difficultly-separated iron and the demands for high-grade concentrate of iron. In this paper, after analyzing magnetic force exerting on iron ore particles within different separating sections of SHP HIMS, it is proposed to apply the flowing-film technique into the HIMS. Thus a new-type LY matrix is designed to form magnetic gradient vertically, combined with a special flowing-film feeder to improve the existing SHP HIMS. The moving pattern of magnetic particles in pulp in HIMS separation district also has been analyzed in this paper. And the test on the SHP-F700 HIMS shows, under the condition of iron ore containing 30.52% Fe, with particle size of ?0.074 mm accounting for around 75%, if applied with flow-film technique, the iron recovery will be up from 69.45% to 76.07%, by 6.62 percent, with the same grade of concentrates of iron. The calculation of iron yield of every size fraction and the tests showed that film magnetic separation (Film-MS) could promote the iron yield of each size fraction, denoting an excellent result of application of the film technique to SHP HIMS. The mechanism of the film magnetic separation technique is to convert the turbulent flow and disordered movement of dynamic mass particles in the pulp into a directional and ordered laminar flow along the surface of tooth plate so as to strengthen the separation effects.

Jan 1, 2014

By V. A. Ivanova

Modification of hydrophobic part of carboxylic collector molecule is an upcoming trend for producing new reagents and changing its flotation properties such as activity, selectivity, sensitivity to hardness salts that inevitably present in the pulp liquid phase in the processing of ores containing calcium minerals. A wide range of apatite collectors ? monoalkyl ethers and monoalkylamides of dicarboxylic acids ? succinic, o-phthalic and maleinic acids have been synthesized by the addition of aliphatic alcohols and amines with various hydrocarbon radical value (from ?11 to ?16) to anhydride of the corresponding acid. Using computer modeling based on ChemBio 3D program of specialized complex Chem?ffice the calculation was carried out of charge distribution on atoms, energy parameters of molecules for investigated compounds. Calculated values of absolute hardness (?=6.75 ? 12.36) and absolute electronegativity (?= 5.67 ? 8.90) of the reagents showed that monoderivatives of dicarboxylic acids refer to the ?hard? type of bases. The degree of a charge transfer during calcium compounds formation of considered collecting agents (?N=0.009 ? 0.143) has been computed. Dissociations, micelle formation in solutions of these reagents and its hydrophobic and collecting properties were investigated in respect to apatite. Dependence of bulk, surface and collector properties on collector molecule architecture (double bond or benzene ring and non-ionogenic functional group in the structure of hydrocarbon radical) has been established. It is shown that experimentally determined dissociation constants (??a=5.16 ? 5.60 for succinic acid derivatives and ??a=3.32-3.78 for maleinic and o-phthalic acid derivatives) perfectly correspond to acidic properties predicted by computer calculations. Compounds of monoalkylderivative dicarboxilic acid have been determined optimum in composition and structure. The results of apatite flotation from apatite-nepheline ores of the Khibiny deposit (the Kola Peninsula) are presented here and show benefits of selected reagents. Keywords: monoalkylderivatives, dicarboxylic acids, reagents, microflotation

Sep 1, 2012

By F. M. Isik

Due to not to being our own sources, some energy sources such as oil and natural gas which are used frequently, are not reliable energy sources for our country. Coal is an important energy source that Turkey also has a certain reserve as many countries have. To be able to use for many years the reserves of this source that comes from fossils, there is a great need to make more investigation and development activities on it. On behalf of using more productively the current sources, briquetting facility is represented that commenced production in The Aegean Lignite Establishment in 2005 which is in Manisa, Soma. This facility is a part of General Directorate of Turkish Coal. This facility is run by Soma Coal Establishment that works in return for royalty in a licensed field that belongs to TKI. As the demand of market for 0.5 mm dust coal diminishes, we had to accumulate and stock unmerchantable dust coal. Besides, we have intermixed 0.5- 1 mm powder coal and 0.1 ? 0.5 mm fine powder coal obtained as a result of washing in coal washer with thermic coal with low price as we could not find a client in the market. In this study, the production stages of briquette coal with high quality produced as a result of pressing by mixing 0.5- 1 mm powder coal and 0.1 ? 0.5 mm fine powder coal with molasse and lime, quality control, and data?s obtained about calories and solidity of products were presented. By briquetting of 0.5- 1 mm powder coal and 0.1 ? 0.5 mm fine powder coal washed in coal washer, it became possible to sell these coals on a high unit price and by providing the demand of coal of the market, we contributed to productivity of our firm. Keywords: briquette coal, briquetting, producing stage

Sep 1, 2012

By Gabriel Aguilera, Juan Arismendy

"As a separator machine, the hydrocyclone is one of the most commonly used equipment in different types of industries and particularly in mineral processing, hydrodynamic behavior allows efficient separation, but developing tests to optimize experimental equipment is expensive, therefore Computational Fluid dynamics (CFD) becomes a useful tool for optimizing the geometrical and operational parameters, and allows to analyze and understand the dynamics within the equipment. In the research was developed to simulate of 40 mm hydrocyclone where turbulence model was used Large Eddy Simulation (LES) for the continuous phase, for the generation of the air core and for the interaction of particles at low concentrations was implemented (mixture model), after the simulation was completed validation and comparation was done between simulation values and experimental."

Jan 1, 2014

By M. K. G. Vermaak

Kimberlite weathering has been a topic of ongoing research within De Beers for many years. Using kimberlite weathering as an alternative to crushing has many advantages e.g. power and reducing diamond breakage. Weathering could also possibly be used in conjunction with crushing just to weaken the material and reduce power consumption. These forces have driven current research to investigate whether kimberlite weathering could be utilised for these reasons. Weathering in this context does not refer to weathering over long period of time but rather to disintegration of the material in aqeous media in relative short time periods. Previous published work discussed that the presence of smectite renders kimberlite weatherable and that the amount of smectite determines the rate of weathering (Morkel and Vermaak, 2006). The current work investigates whether cation ex-change or the adsorption of organic species in the smectite interlayer could influence the observed weathering behaviour. The results show that cation exchange does take place in the presence of cation species and that the weathering behaviour can be drastically improved with especially Cu2+ cations. Concentration and time effects of the weathering was also investigated. Weathering tests with organic species such as ethanol, methanol, edta, pentanol, butanol, acetic acid and oxalic acid was performed. The results show that organic species does improve weathering but under these testing conditions was not as effective as cations.

Jan 1, 2014

The molybdenum ores currently utilized in China are mostly molybdenum sulfide ores whereas oxidized molybdenum ores, being finely disseminated and difficult to process, have not been exploited and utilized effectively. In this article the beneficiation process of a molybdenum ore occurred in an oxidized ore zone was investigated in order to provide a new way for the development and utilization of the oxidized molybdenum ores in China. The molybdenum mineral in the ore was mainly wulfenite and the associated minerals included barite, limonite, quartz and small amount of cerusite. Limonite in the ore occurred in a crust and honeycomb-like colloidal state and composed the framework for the formation of the other minerals in the ore, which filled the pores in the framework. Wulfenite was mainly fine-grained and occurred in the fine porous crust and honeycomb-like framework. The finely disseminated ore structure made the separation and recovery of the molybdenum mineral in the ore very difficult. On the basis of the mineralogical study of the ore, experiments were conducted to compare the various mineral processing methods for the beneficiation of the ore, including single gravity concentration, single magnetic separation, single flotation, and a combination of high intensity magnetic separation and gravity concentration. The results indicated that with single gravity concentration a molybdenum concentrate containing 5.85 % Mo with a yield of 11.76 % and a Mo recovery of 43.5 % was produced. With single high intensity magnetic separation it was very hard to obtain a molybdenum concentrate product. With single flotation process a molybdenum concentrate containing 7.06 % Mo with a yield of 15.14 % and a Mo recovery of 62.63 % was produced. With a combination of high intensity magnetic separation and gravity concentration a molybdenum concentrate containing 6.46 % Mo with a yield of 11.81 % and a Mo recovery of 42.11 % was produced. In conclusion, compared to the other methods the flotation process can produce more reasonable technological and economical results and is the best process for the exploitation and utilization of the finely disseminated oxidized molybdenum ore.

Jan 1, 2014

By Sergey Dyachenko

"Following the adopted strategy for making the production modern, efficient and environmental friendly the Company completed a stage of the integrated program aimed at reconfiguration of its processing capacity.Upgrade of the Talnakh Concentrator with commissioning of two start-up facilities (SF) allowed an increase of 30% in its ore processing capacity up to 10 mtpa. In addition to a new high-tech equipment installed, a new concentration process was adopted offering the main advantage of 25-30% reduction of sulfides in concentrate. New concentration technology enabled the total amount of produced nickel concentrates (from Norilsk and Talnakh Concentrators) to be processed at upgraded smelting facilities of Nadezhda Metallurgical Plant and allowed decommissioning of smelting capacities of Nickel Plant resulting in emissions reduction by 30%.Nornickel plans to boost the capacity of Talnakh Concentrator to 18 mtpa by 2022, after commissioning of the 3rd SF. This will provide a shorter route for ores transportation from Talnakh mines along with improvement of cost/performance ratio of ore processing through the usage of the modern equipment and optimized concentration flow scheme. Total capacity of Talnakh Concentrator will be sufficient to process ores from Talnakh deposits with planned upstream assets development taken into account. Volume of ore mined from Norilsk deposits to be processed at Norilsk Concentrator will be also increased.Upgrading the crushing section at Kola MMC Concentrator in 2015 provided finer particles of the crushed ore, resulting in 6.6% increase in specific capacity of ore mills as well as 1% higher recovery of non-ferrous metals due to improved liberation of ore minerals.In 2015-2017 the Company was actively engaged in optimization of existing process flow schemes and parameters of Kola MMC, new high-performance reagents were adopted for concentration process, namely, collectors, depressors, flocculants. These measures allowed the Concentrator to reduce its annual operating unit costs and ensure sustainable production of concentrate with the lower grade of the incoming feedstock.Launched in October 2017, Bystrinsky GOK’s Concentrator was 3D designed and received a range of advanced technological solutions.All design process procedures and technologies rolled-out at the Company’s concentrators were developed by Russian R&D institutes, with the key role of Gipronickel Institute, R&D Service of Kola MMC and Polar Division's in-house Engineering Support Centre."

Jan 1, 2018

By M. Tang

The phosphate ore sample was taken from the iron tailings after recovering most of magnetite by magnetic separation in Longlin, Yunnan Province of China. Batch flotation tests had been conducted to upgrade the phosphate concentrate by conventional fatty acids reagents under 70% -75 µm of the particle size; however, the unsatisfied results (P2O5 grade of 27.84% and recovery of 49.25%) were obtained. Also there are a large amount of slimes trapped in the concentrate and high-dosages consumption of reagents, for example, more than15 kg/t soda ash and 2 kg/t sodium silicate at only one-staged roughing. Based on the analysis of X-ray diffraction (XRD) for the sample, most of gangues are clay, quartz, and chlorite, which may easy to over-grind and deteriorate the flotation process either on reagents consumption or slurry fluidity or viscosity. A hydro-cyclone had been introduced to pre-concentrate the phosphate ore by scrubbing the slime before flotation, which can result obviously in reducing the dosages of soda ash from 15 Kg/t to 4 Kg/t, and raising the grade of P2O5 in the concentrate from 27.84% to 36.13% at the expense of about 4% recovery of P2O5. They also substantially reduced the time of sedimentation of concentrate after flotation from ~10 to ~1 min. In this paper, the effects on the recovery of P2O5 by the different dosages of flotation reagents with or without de-sliming were studied, with the objective of determining the different effects on the functions of flotation reagents by slime during flotation. Keywords: de-sliming, phosphate, soda ash, flotation

Sep 1, 2012

With rapid development of Chinese iron & steel industry, it is of significance to intensify the utilization of domestic complex iron ore resources. The tin, zinc-bearing complex iron ores are typical polymetallic and intractable ones because of the complicated intergrowth relations among the multi-elements, and they have not been efficiently utilized, presently. Based on the thermodynamic analysis of iron, tin and zinc oxides reduction by CO, the technological conditions of tin and zinc recovery and pellets preparation from tin, zinc-containing iron concentrates by selective reduction roasting are studied and a new comprehensive utilization process is developed in this investigation. Under the optimum conditions, the tin and zinc volatilization is respectively in excess of 80% and 70%, and the compression strength of roasted pellet is more than 2500 N/P. Moreover, the residual tin and zinc in the finished pellets is below 0.06%. The finished pellets can be used as high quality iron-making burdens for large-scale blast furnace.

Jan 1, 2014

By D. Renda

With thise Process of obtaining a solid fuel which is both ecological clean and has a high calorific value by a two-stage method of enriching preferably type lignitic coals to remove a high content of all sulphurs, incuding organic sulphur, which method comprises converting the coal to a semi-coke from followed by magnetic separation. In the Experiments given the best results the washed lignite coal in the West-Turkey, Tavsanli- Region, size -3.35 mm on dry basis. In the microscopic studies of the brigh-thin cross-section taken from the samples of sulfur min-erals pyrite in the dimension of 2~50 micrometers and melnicovite 10 micrometers particles. An thermal treatment an semi-coking themperature between 370°C to 650°C give the best Result of 480 °C. The oxidation and decomposition of sulphur minerals pyrite and melnicovite in lignite coal proceed the iron oxides Fe2O3 and pyrrhotite FeS on the surface layer. The Magnetic Seperator (Rare Earth Magnetic Separator, REMS) is capable this two form of sulphur, including organic and inorganic sulphur, in semi-coke and resulted in the magnetic-fraction in REMS. The non-magnetic-fraction remove total sulphur by 68 %, ash by 44 % and increase the upper calorific value in 15 %. The clean lignitic coal can be utilized in human or energy power stations.

Jan 1, 2014

The Sydvaranger magnetite mine was shut down in 1996 due to low iron ore prices. It was reopened in 2009. The flowsheet has remained more or less as in the old plant, based upon two grinding steps followed by magnetic separation. The Sydvaranger magnetite is free of harmful elements and should therefore be sold on the high quality market. This requires a concentrate containing less than 2 % SiO2. In the old plant, this grade was achieved by amine flotation. Amine was preferred as collector because it could be used in process water from the sea. The use of amine has been restricted by the Norwegian pollution authorities during the time the mine was shut down. Test work to replace cationic with anionic flotation is therefore done. Research on activation of quartz with Ca or Mg ions prior to anionic flotation was shown by basic research in the period from 1960 to 1980 to be effective under simplified laboratory conditions. This old research has now been followed up from a practical/empirical point of view. The basic work was mainly done on quartz and iron minerals only. In this case, an actual feed containing a number of minerals common in iron ores is used, in order to demonstrate that a commercial process is possible. Calcium activation is shown to work excellently but requires too high pH to be environmentally and economically attractive. Magnesium activation is a more difficult process, because the maximum concentration of MgOH+, which was shown to be the activator, is about 100 times lower than the alternative CaOH+. Flotation success depends partly upon the ore, some amphibole minerals are more difficult to float than pure quartz. Ordinary batch flotation test work is time consuming. A South African microflotation test cell has shown promise, because work can be focused upon flotation of the more critical coarser fractions of the Sydvaranger ore. Keywords: iron ore concentration, anionic flotation, mineral activation, microflotation, Sydvaranger

Sep 1, 2012

By J. A. Sweet

The issues facing graduate training in the mineral processing industry are not too different today from those that prompted the initiation of the Anglo American Platinum Graduate Development Programme (AGDP) in 2002. Graduate metallurgists in South Africa enter the industry from different undergraduate programmes at various tertiary institutions, and so the knowledge and skills of the young graduates varies. Further, the geographical expansion of the industry combined with the downsizing of business units means that there are fewer opportunities for young graduates to be mentored through their first few years on site. Anglo American Platinum chose to address these issues by implementing an intensive, structured graduate training programme for all their new metallurgical graduates, known as the AGDP. The first two years of experience of the AGDP, from the viewpoints of both graduates and lecturers, were presented to the mineral processing community at the IMPC in Turkey in 2006 (Sweet et al, 2006). From the beginning, the programme was structured in a modular fashion to include a basic technical ?toolbox? including statistics, the scientific method and sampling protocols, while the mineral processing content comprised advanced learning in comminution, classification and flotation (later extended to include hydrometallurgy). Technical communication ? both written and verbal ? was included from the start. The programme was focussed very strongly on site work (?learning by doing?), with a major integrated site campaign conducted and analysed by each cohort. In 2012 the AGDP will accept its ninth cohort into the programme. This paper describes how Anglo American Platinum and the University of Cape Town have developed and adapted the programme over the last few years, in response to the challenges of the global recession, skills retention, and the changing operational needs of the company. The programme, which was drawn up to accommodate around 15 concentrator-only graduates, now accommodates 35-40 concentrator, smelter and refinery graduates annually. The programme has also been modified to facilitate new graduates spending most of their first year on the operations. The benefits of the programme for Anglo American Platinum have been tangible, and will be discussed in the paper. Keywords: graduate training, technology transfer

Sep 1, 2012