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By Alejandro Yañez, Martta Nousiainen, Rodrigo Grau

"Gas dispersion plays a fundamental role in froth flotation. Gas dispersion in flotation is quantified by using four properties: gas velocity, bubble size, gas hold-up and bubble surface area flux. Gas dispersion measurements were conducted in three flotation cells: TankCell 1, TankCell e300 and TankCell e500. The measurements reported in this paper were carried out exclusively in two-phase systems using only water and air at frother dosages exceeding the Critical Coalescence Concentration (CCC) in order to prevent bubbles from coalescing. The measurements conducted in TankCell 1 and TankCell e500 were conducted by Outotec specialists, whereas the characterization of TankCell e300 had been conducted earlier in 2008 by a team from McGill University. When working in two-phase systems and under non-coalescing conditions, gas dispersion characteristics measured in different scales can be compared directly. The measurements conducted in TankCell e300 are taken as a base line in order to compare the performance of TankCell e500, whereas TankCell 1 is a pilot-scale flotation cell which is used in rotor testing. The gas dispersion properties in TankCells were found to be affected by the air flow rate and rotor tip speed. Bubble sizes (d32) measured on the three-size scale seem to be within the same range of 0.6 mm to 1.6 mm. It was noted that the bubble size was influenced by rotor tip speed and gas velocity. In general, as the rotor tip speed increased, the bubble size decreased and as the gas velocity increased, so did the bubble size. The rotor tip speed also has an impact on the hold-up; in general, as the rotor tip speed increased the gas hold-up also increased but the influence of air flow rate on gas hold-up was greater. Bubble surface area flux was found to vary between 40 and 85 1/s. As the gas velocity increased, the bubble surface area flux also increased."

Jan 1, 2014

The value creation with kaolin clays depends on removing the colored impurities which manifests in to higher brightnessone of the most sought after properties on applications such as paper coating, paint and others. The processes for removing impurities include magnetic separation, froth flotation and selective flocculation. While the flotation and selective flocculation processes exploit the physico-chemical differences between the surface properties, the magnetic separation uses the bulk magnetic susceptibility differences between the diamagnetic clay and ferro- and para-magnetic nature of the impurities. The major advantage with magnetic separation remains high yield and no or low reagent usage. However, the magnetic separation technology suffers from low separation efficacy when finer colored impurities (<1 µm) are encountered in the feed. Use of stronger magnetic intensities during magnetic separation showed limited success; nonetheless the adverse effect due to finer size range remains a dominant effect even at 5 Tesla magnetic field. Furthermore, the presence of diamagnetic colored impurities irrespective of their sizes can not be removed. Cytec Industries has recently developed a ?bolt-on? chemical enhancement technology for magnetic separation that essentially embraces the best product performance attributes of flotation and selective flocculation while keeping the chemical usage to a minimum level and using the readily available magnetic separation equipment. The paper will outline the technology and illustrate optimization work at pilot plant magnet on a wide variety of crude accommodating the process needs and plant limitations. The major advantages of chemical enhancement technology to magnetic separation include: 1) simple extension to existing magnetic separation technology, 2) ability to produce comparable product in quality with cost effectiveness compared to flotation and selective flocculation, 3) removal of impurity minerals over wide size range, 4) removing non-magnetic impurities, 5) providing robust process with high process yield and 6) operation-friendly nature. Furthermore, chemical enhancement technology for magnetic separation has also emerged as a platform for re-moving impurities at low levels in other mineral systems as well.

Jan 1, 2014

By Jacob Masliyah, Zhenghe Xu, Lujie Yan

"Understanding adsorption mechanism of polymeric organic process modifierssuch as carboxymethyl cellulose (CMC) on talc hasbeen a major challenge due to anisotropic nature of talc basal planes and edge surfaces. The main objective of this study is to investigate the adsorption of CMC on the basal planes and edge surfaces of talc.Smooth basal plane and edge surfaces of talc were prepared successfully by simple cleavage and sophisticated ultramicrotome cutting method, respectively. The prepared surfaces were characterized by atomic force microscope (AFM) imaging to be sufficiently smooth for colloidal probe force measurements using AFM. Anisotropic surface charge characteristics were determined,with the basal planes to carry a permanent negative surface charge and edge surfaces featuring a pH-dependent charge characteristic. The adsorption of CMC on talc basal plane and edge surfaces at pH 9 in KClaqueous solutions of various ionic strengths wasinvestigated by in situ AFM imaging technique. Themorphology of adsorbed CMC on talc basal planes and edge surfaces was found to be significantly different, due to different binding mechanisms involved. Interaction of CMC with the talc basal plane was found to bedominated by hydrophobic interactions while its binding with the talc edge surface was mainly through chemical complexation and hydrogen bond. The amount of CMC adsorbed on both talc basal planes and edge surfaces increased with increasing ionic strengthof solutions. The methodology developed in our study opens the door to probe polymer adsorption on anisotropic phyllosilicate surfaces, which can help us better understand the mechanism of polymer adsorption on specific mineral faces."

Jan 1, 2014

By J. Ma

Vanadium ore is widely distributed in black rock series (Fan, Zhang and Ye, 2004) in many provinces of China, which accounts for 87% (Zuo, Peng and Dugang, 2001) of vanadium reserves in China. In Cambrian black rock series in south Qinling Mountain, there are large or medium-sized sedimentary deposits such as Zhongcun vanadium deposit, Yinhua vanadium deposit, Qianjiaping vanadium deposit, Xiajiadian gold-vanadium deposit and Lengshuigou vanadium deposit. The vanadium is distributed in other minerals mainly in the form of isomorphic replacement. These types of ore are characterized by no independent vanadium mineral, low grade and vast reserves. Now in China the vanadium extraction technology is backward with low utilization rate of resources. The difficulties of vanadium extraction from black rock series are that the enrichment by means of mechanical beneficiation is difficult; the cost of direct chemical extraction is high and the emission of waste gas from pyrogenic process does not conform to environmental protection standard. Therefore the study of vanadium occurrence, the improvement & optimization of vanadium extraction technology and the realization of pollution-free and low-cost extraction of vanadium from black rock series are of great and realistic importance for environment-friendly exploitation & utilization of vanadium resource in China. The study is based on carbon content in ore of Cambrian black rock series in south Qinling Mountain. Two kinds of ore are selected. Vanadium ore with low carbon content (TC<1%) is taken as Sample 1 while vanadium ore with high carbon content (TC>10%) as Sample 2. Based on analysis of ore?s lithologic features and vanadium?s occurrence, a vanadium extraction technological process characterized by selective grinding, low cost and no pollution is proposed.

Jan 1, 2014

Anglo American Platinum practices fine grinding in its processing plants to enhance the liberation of valuable minerals. If the fine particles of valuable minerals generated during fine grinding are not recovered during the flotation process, this could significantly contribute to the overall losses. This study examines the flotability of fine moncheite (PGE mineral) particles in a controlled environment (moncheite size distribution, concentration and liberation). A barren Norite ore ground to 40% and 80% passing 53µm was spiked, with four different size fractions of moncheite (-5, -10+5, -25+10 and -53+25µm) in order to evaluate the effect of particle size on flotation. The investigation also included the effect of energy input and collector dosage on the flotation of two moncheite size fractions, namely -5µm and -10+5µm. The results showed that the moncheite particle size has a significant impact on flotation. Coarse particles (-53+25µm) showed the highest Pt flotation kinetics and overall recoveries. The -5µm size fraction of moncheite could also be recovered by flotation, however, at a lower rate compared to the other size classes investigated. The increased collector dosage of 300g/t at the finer Norite grind of 80% passing 53µm enhanced the flotation rate of the -5µm size fraction of moncheite when compared to the lower collector dosage of 150g/t. The higher energy input during laboratory flotation, at an impeller speed of 1000rpm also increased the flotation rate of the -5µm size range, however, at a lower concentrate grade, when compared to the lower impeller speed of 700rpm. More favourable Pt flotation kinetics data was obtained for the -53 +25µm size fraction of moncheite at the fine Norite grind when compared to the coarse Norite grind. Keywords: flotation, moncheite, particle size, energy input and SIBX

Sep 1, 2012

By D. Govender

Theoretical flotation models suggest that there is a positive relationship between bubble-particle collision rates and turbulent kinetic energy dissipation. Fine particle flotation performance is generally enhanced by increased collision frequency and hence higher energy dissipation. Contrarily, increased turbulence in the rotor-stator region is related to higher detachment frequency of the coarser size range. Therefore, the optimal modes of recovery for the ?fine? and ?coarse? size classes are diametrically opposed. Industrial applications have previously confirmed that applying greater power to flotation slurries yields significant improvements in fine particle recovery. However, recovery of the coarser size class favors a different flotation environment. An improvement in the kinetics of the fine and coarse size classes, provided there is no adverse metallurgical influence on the intermediate size ranges, is obviously beneficial to the overall recovery response. Managing the local turbulent kinetic energy dissipation, and hence the power imparted to the slurry, offers the benefit of targeting the particle size ranges exhibiting slower kinetics. FLSmidth recently introduced the practical implementation of this concept. In principle, it decouples flotation regimes where fine and coarse particles exhibit preferential recovery. In the case of naturally aspirated machines (Wemco®), it is referred to as Hybrid Energy Flotation? and incorporates at least three phases: ? Standard flotation machines (standard energy input, rpm, rotor size/type) at the beginning of the row, where flotation is typically froth phase limited and operational, and set-up parameters have a limited influence on the recovery. ? Higher-powered flotation machines (high rpm, high power rotor size/type) at the end of the row to improve fine particle recovery. ? Lower-powered flotation machines (low rpm, low power rotor size/type) to enhance coarse particle recovery. In evaluating the effect of turbulent kinetic energy on flotation performance, the spatial distribution and its effect on size denominated recovery needs to be evaluated. The mean energy dissipation rate is a measure of the bulk energy input, but CFD-based models offer a more introspective view of flotation sub-processes. A CFD-based flotation model is used to highlight the effect of turbulent dissipation energy on attachment and detachment rates. Preferential collection zones for ?fine? and ?coarse? particles are predicted for both forced air and naturally aspirated machines. Keywords: CFD-based model, attachment, detachment, energy dissipation, hybrid energy flotation?, forced air, naturally aspirated

Sep 1, 2012

By P. A. Bepswa

A numerical study done to test the efficacy of heuristics developed for the design of measurement networks for high precision metallurgical accounting is presented in this paper. The heuristics considered were designed to maximise variance reduction of terminal stream measurements through data reconciliation for observable linear flow systems. A complex metallurgical process flow sheet from the mineral sands industry was used as a case study. Monte Carlo type simulations coupled with a non-linear programming based steady state data reconciliation algorithm were used as tools to investigate the heuristics. The results obtained suggested a close correlation between magnitudes of measured variances and the respective levels of variance reduction obtained through data reconciliation for both internal and terminal streams. It was observed that variance reduction through data reconciliation was maximised for terminal stream measurements in networks characterised by high precision measurement of internal streams and/or in flow sheets characterised by high ?stream to node ratios?. Terminal streams attached to highly interconnected parent nodes were observed to experience higher reductions in variance compared to terminal streams attached to less interconnected parent nodes. The results generally highlight the additional benefits of highly interconnected flow sheets and high precision internal stream measurement regimes on the maximisation of variance reduction of terminal stream measurements through data reconciliation. These findings are significant to metallurgical accounting and to process accounting applications in general in that they provide a conceptual basis for design decision making regarding the construction of measurement networks aimed at maximising variance reduction of targeted streams through data reconciliation.

Jan 1, 2014

By A. L. Hinde

The steady-state and dynamic behaviour of semi-autogenous grinding (SAG) mills are arguably best described using a population model that caters for the breakage kinetics and the material trans-port of rock and pulp inside the mill. Breakage kinetics are usually expressed in terms of a specific breakage rate function and a separate primary breakage distribution function. Material transport usually invokes the concept of a specific discharge rate function. Unfortunately, the breakage rate and breakage distribution functions for SAG mills are very difficult to estimate uniquely from plant data alone. Simplifying assumptions must be made to over-come this problem, which leads to many unresolved dilemmas with regard to whether or not the de-rived functions are accurate, precise, and reflect reality. For example, it is sometimes assumed that the breakage distribution function for a SAG mill treating run-of-mine ore can be derived from laboratory dropweight and tumbling tests on small rocks in narrow size ranges. Such tests hardly reflect the environmental conditions likely to be encountered in a pilot or production SAG mill where there is a wide spectrum of particle sizes. It is shown that the dilemmas associated with standard population balance models (models that utilise separate breakage rate and breakage distribution functions) can be overcome by expressing breakage behaviour inside a SAG mill in terms of a single function. This function is an energy-based cumulative breakage rate function defined as the fractional rate at which particles and rocks coarser than a given size break to below that size per unit specific energy input. A model for SAG milling is formulated, which invokes the concept of a cumulative breakage rate function. Comparisons are made between the mathematical structure of this ?simple model? and standard population balance models. Perhaps the most attractive feature of the ?simple model? is that the cumulative breakage rate function can be uniquely estimated from measurements of size distributions and mass flows of the feed and discharge streams together with the size distribution and holdup mass of the mill charge. Such measurement can easily be made at pilot scale. It is concluded that this simplified approach to SAG milling may turn out to be the quickest way to fully describe and quantify the performance of these very complex mills.

Jan 1, 2014

By U. M. J. Boin, E. V. Verhoef

Pyrometallurgical reactors constitute a key processing component in the total primary and industrial/recycling resource cycle, being involved both in primary smelting, converting and extraction, as well as the reprocessing of scrap, from aluminium cans to end-of-life automobiles. Therefore the pyrometallurgical reactor?s role in achieving sustainability is the central theme discussed in this paper since optimising their operation minimises waste, residue and offgas (NOx, dioxin, CO2) and maximises product quality and therefore efficiency. To effectively control the overall resource cycle, one needs to take a systems modelling approach of the whole cycle, seeking to also understand the dynamic process behaviour of the individual components of the cycle, and then especially the part that contributes most to the chemical conversion, namely the pyrometallurgical reactor. This paper highlights the role of pyrometallurgical thermodynamics in the whole resource cycle and specifically places equilibrium thermochemistry in the context of process dynamics where large, variable inventories are recycled or maintained within the system. This paper will therefore review the semi-empirical dynamic modelling tools, which are used to model complex systems with the specific goal of developing dynamic predictive models, which also include slag-alloy chemistry, towards controlling the recycling in a feed forward manner. To illustrate the primary production of metals, high carbon ferrochrome and Ni-Cu-matte smelting will be presented as a brief case study. Also fundamental studies in blast furnace and waste incineration kilns will be given. It also will show how the distributed nature of the chemistry of melts in the case of primary extraction, and industrial (recycling) materials such as recycled end-of-life vehicles, have a significant impact on the process outcomes and model predictions. It is therefore argued that the fundamental thermodynamics and kinetics in metallurgical reactors play a final crucial role in modelling the closed material cycle, but only when it is used in conjunction with process systems theory based on reconciled data for parameter estimation and model calibration. System models for aluminium and car recycling will be given as well as a dynamical system model that describes the interconnected material flows for Ag, Au, Bi, Cu, Fe, Ni, Pb, PGM, Sn and Zn for a study on lead-free solder.

Jan 1, 2003

By Y. D. Gao

A new technique has been developed for comprehensively recovering tantalum niobium tungsten ore by adoption of stage grinding, stage separation, combination of flotation and gravity separation, gravity separation for coarse particles, flotation for fine ones, combination of ore-dressing and hydrometallurgy. The new type and high efficiency combinative collector mainly composed of benzyl hydroxamic acid is firstly used to treat tantalum niobium and tungsten slime, besides the new type equipment for gravitational separation ?YTF-C shaking table for fine particles is adopted to treat flotation rough concentrate, hence having notably enhanced both recovery and concentrate grade of fine tantalum niobium and tungsten minerals. The commercial test obtains the tantalum concentrate assaying Ta2O5 31.98% with recovery 43.44% and tungsten product assaying WO3 89.40% with recovery 76.02%. The developed technique provides a reliable approach and an effective way for comprehensive utilization of lean fine complex refractory tantalum niobium tungsten ore resource.

Jan 1, 2014

By Baidyanath Mandal

Technology in the solid-liquid separation industry has evolved rapidly during the last fifty years and from the beginning, DIEMME Filtration has played a very important role in this evolutionary process by developing innovative solutions, which are used for a diverse range of industrial applications. Since the last decade, we find more and more examples of filter presses employed in the mining & mineral processing field, where high performances in terms of productivity, dewatering capacity and mechanical strength even in extreme working conditions are required. Mainly the requirement of such high quality equipment comes from the Process, however in few cases the reason could be linked with the environment. For stringent process applications like Mineral Concentrates dewatering & leached Slurry Filtration, it requires a high quality & extremely reliable equipment. In these applications, since many years industries are achieving the desired result by using Diemme Filter Presses. Also, recently, due to stringent environment practices are been applied globally, industries needs equipments which could dewater a high amount of residues / tailings with minimal moisture content in the filtered cake. In comparison to all the conventional dewatering equipments, Diemme Filter Presses are most efficient for these kind of product & applications. Diemme Filtration is a highly professional & technological company with several decades of experience in designing equipment for mineral processing. We take up each project as separate & design and manufacture equipment based on individual process or project requirement. This presentation will be focused on the Solid-Liquid separation technologies & equipment Diemme Filtration offers to the mineral processing Industries. It consists of Diemme?s History, Global Network, Technologies & Expertise, R & D Capabilities, Manufacturing Range, Some Applications & results on different mineral processing. Keywords: solid-liquid separation, filtration, dewatering, filter press

Sep 1, 2012

By M. Guo

Coal-based Direct Reduction in Interior-combustion Shaft Kiln (CDR/ISK) is a brand-new technique. Compared with the traditional Coal-based Direct Reduction (CDR) technique, its main character is to use Interior-combustion Shaft Kiln (ISK) as the reactor of direct reduction. After being crushed and grinded, iron ore is made into green pellet, which will be surface-coated by coal fines. Then, the surface-coated green pellet can be directly reduced in ISK. The pellet should not be too dry and should be charged from the top of ISK. Oxygen-contained air should be blasted into ISK to keep the temperature in it higher than 1000 degrees centigrade, at which iron oxide will start direct reduction. The reduced pellet will be discharged from the bottom of ISK and after de-surface-coated, spherical Direct Reduced Iron (DRI) can be gained. The volume of carbon monoxide in the off-gas discharged from ISK is less than one per cent. By using this technique to get one tonne DRI, the consumption of coal is about 300kg of fixed carbon, which is much lower than the energy consumption by using other CDR techniques. There is a lot of complex refractory iron ore in China, which remains unexploited. The iron-bearing minerals in this kind of the iron ore can not be beneficiated economically by present technique of gravity, magnetic, flotation or magnetic roasting because the iron minerals are too very finely disseminated to be liberated, or, the iron minerals are too similar to gangue to be separated each other. By using CDR/ISK, complex refractory iron ore can be directly reduced in lower temperature and all kinds of iron mineral can be turned into iron metal. As the grains of iron metal growing larger during direct reduction, magnetic separation can be used to separate iron metal from gangue mineral, thus high-grade iron metal fines can be gained. According to the experiments, the grade of iron metal fines is above 90 percent and the recovery of iron is higher than 90 percent. The consumption of coal to process one tonne of complex refractory iron ore is only about 90kg of fixed carbon.

Jan 1, 2014

Three high-grade limestone ores (CaO content over than 53 %) with different geological origin have been characterized for the synthesis of aragonite precipitated calcium carbonate. Limestone ores examined in this study showed different crystal particle size that cause difference in disintegration degree and surface area of the synthesized slaked limes. The limestone ore with smaller crystal particle size showed higher disintegration degree and also yielded slaked lime with smaller surface area, which is good for the synthesis of aragonite precipitated calcium carbonate. The synthesis of aragonite PCC using the limestone with a small crystal particle size was yielded needle-shaped aragonite with the aspect ratio of about 14. Keywords: limestone, lime, slaked lime, precipitated calcium carbonate, aragonite, accelerated carbonation

Sep 1, 2012

By M. Kargar Razi

According to the unique properties and many applications of nano gold powder, it was prepared from an acid leaching tail solution. The low value residual gold ions were existed in acid leaching tail solution in Mouteh gold mine in Iran with fellow heavy metals as pollutants (FeP2+P, Cu P2+P, and ZnP2+P). Preparation of nano gold particles is achieved by two steps. First, by addition of ammonia as separation step and second using suitable reagents for precipitation/extraction step. Conditions control includes pH, residence time, temperature, agitation, and molar ratio of reducing agents to reagents. The optimum results show that nano gold powder was prepared by temperature of 250 °C, urea to gold molar ratio of 3:1, and reduction time of 20 min. Also, heat treatment improves dispersion of nano sized gold particles. The properties of gold nano powders were evaluated by SEM, A.A, and UV- Vis spectroscopy methods. The size of prepared particles were about 80nm to 90nm.

Jan 1, 2014

By R. Venugopal

The paper reviews the development of Mineral Engineering education and training programmes in India. It highlights the major academic programmes and describes the evolution of the curriculum and design of courses in response to the changing requirements of India?s mineral and coal industries. An outline of the efforts needed to sustain and further improve the existing programmes is also provided. Keywords: manpower, mineral engineering

Sep 1, 2012

By R. J. Batterham

The science and practice of mineral processing has been driven for many years by the same set of challenges that shape the mining industry ? demand and supply, grades and their decline with time, mineralogy and the need to handle more complex ores, disposal and minimising of wastes and the availability of water, power, skilled labour and the like together with increasing expectations from the community, concerns on sustainability and safety and, as well, climate change forcing a more targeted approach on energy. In this paper, the author builds on previous reviews to the IMPC and suggests that while step changes are long overdue, the unprecedented demand mitigates against drastic changes. That said, the ?Mine of the Future? is already requiring some different approaches.

Jan 1, 2014

By C. R. Mambote

One of the processes developed for vanadium recovery from the fly ash of crude oil is through acid leaching. In the process, iron is one of the impurities that should be removed before vanadium precipitation, due to the fact that iron tends to co-precipitate with vanadium. The mechanism of iron precipitation is understood in terms of ferric hydrolysis, followed by the dimerization and subsequent polymerization of the crystalline iron compound. In order to develop a new approach for the fly ash processing, in the present paper the precipitation of iron from the liquor after the leaching process was studied with addition of NaOH or NH4OH in the presence of H2O2 or Na2C2O4 at 80°C. The objective was to investigate the feasibility of the selective precipitation which could be applied to vanadium and nickel recovery from the fly ash. The experimental results show the difficulties of removing iron by precipitation without co-precipitating nickel and vanadium.

Jan 1, 2014

By V. Sheikhzadeh, M. Saghaeian, R. Hejazi, A. Abazarpoor

The research aimed to compare the chemical analysis (K, Na, Cl) of Iranian concentrate plants, which are the main source of materials corrosion in the pelletizing plants. Cl alongside alkaline elements (especially K) may cause corrosion and plug in the grate plates and other involved equipment. Therefore, it is tried in the processing plants to remove impurities from the concentrate to prevent potential problems in pelletizing and iron/steel making processes. Part of these impurities are existed in the nature of ores and others are sourced in the processing water. Various samples from the largest Iranian concentrate plants including Chadormalu, Gol-e-Gohar, Jalal-Abad and Sechahun were prepared to investigate the possibility of alkaline problems for each samples. The amount of Cl, K and Na of Chadormalu sample was obviously low and therefore no alkaline problem is expected. The Cl content of Gol-e-Gohar sample was high (980 ppm) while amount of K was less (0.008 Wt. %). Due to low content of K, most of Cl will release as Cl2 or HCl and so problems caused by KCl plugging would not be a problem. The amount of Cl in Sechahun case was nearly same as Jalal-Abad (400-600 ppm), higher than Chadormalu and less than Gol-e-Gohar samples. However, the K content was higher than all samples (0.04 Wt. %). Therefore, the amount of evaporated K would be 2-4 times more than other samples. Since the amount of Cl and K is simultaneously higher than usual iron ores, therefore alkaline problems may be a serious prevention factor for the continuous operation of this plant. In order to solve this problem some counter-measures is suggested and discussed including cleaning system, partial dust enriched with KCl removal and variation in the materials type of involved equipment.

Jan 1, 2018

By Kr. J. Dedelyanova

Selective flocculation of iron minerals could improve the economics of high intensity magnetic separation as concomitant process. When the minerals are finely disseminated is necessary a finer grinding to be applied which generates a lot of slimes. The HIMS is not enough efficient for particles below 20 microns ? territory where the selective flocculation is already well known industrial practice, so the combination of these two methods of beneficiation can bring a higher grade at high recovery to be achieved. The dynamics and selectivity of the precipitation process is studied in batch tests with flocculant starch and dispersants sodium silicate and sodium hexametaphosphate. The influence of preliminary conditioning with nitrogen acid at pH 2 before flocculation is also investigated. Flowsheet including these two methods is tested and the distribution of iron is shown.

Jan 1, 2014

By B. Aydin, G. Erturk, G. Bulut

Coal is a complex material because of its structure consisting of carbon constituents and mineral matter. Flotation is readily carried out due to hydrophobic characteristic of coal. Therefore coal flotation is the most commonly used technique for fine coal beneficiation in order to acquire clean coal separating ash forming mineral matter from carbonaceous matter. In the coal flotation, floatability of coal both depends on characteristic of coal and used flotation reagent. Frothers as a flotation reagent are used to facilitate air dispersion into fine bubbles by prevention of bubble coalescence in the pulp phase, and stabilization of flotation froths. In this study, the effects of frother types and concentrations at different pH and particle size on the coal flotation were investigated. The representative sample was taken from Zonguldak, Turkey. It contains 9.1% ash and 7313 (kcal/kg) calorific value. Pine oil, Dowfroth 250, MIBC and Isooctanol were tested as frother types. It is determined that 1.92 ppm frother concentration is sufficient to float coal, except pine oil. In mixed frother tests, it is seen that Dowfroth 250 is more effective than others. No significant difference in coal recovery was observed for flotation tests at the different pH values. The best results are obtained in size of coal (-0.1 mm) with all frothers.

Jan 1, 2014