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By Mario Gerards

Maturing populations create an increase in the demand for the type of non-ferrous metals, which are used in the manufacturing of electronic products. The depletion of existing high-grade deposits, make it necessary to boost the efficiency of beneficiation processes and most importantly the yield (recovery rate of the value commodities). Increasing demand now makes it worthwhile to tap into resources, which were previously considered waste, for example secondary deposits such as tailing ponds and electronic waste. In order to achieve increased yields, increasingly finer, or even ultra-fine fractions have to be treated. In most cases, mineral characteristics such as size and density call for non-mechanical, high-capacity technologies to be used. There are various technologies that allow for the separation of fines and ultra-fines. This paper outlines the dynamics and efficiency of pneumatic flotation with emphasis on its application to the recovery of non-ferrous metals, from electronic waste. The conventional agitator flotation technology of an electronic waste processing plant was not able to recover ultra-fine non-ferrous metals satisfactorily, due to losses within the tailings. Because of its adaptability and its inherent suitability for non-ferrous metals, pneumatic flotation has been incorporated to the existing process achieving excellent results. The merit of the process lies in the state of the art technology, which does not utilize compressed air and any rotating parts, which results in a reduction in wear and energy requirement, both features of this innovative technology. In addition, the use of pneumatic flotation resulted in a significant reduction in residence time, when compared to mechanical flotation. Pneumatic technology is able to influence air bubble size in a flotation cell, by changing the speed and pressure of the slurry stream. Higher slurry velocities lead to the formation of smaller air bubbles, which is required for the successful flotation of ultra-fine particles. Conversely, decreasing the slurry velocity leads to bigger air bubbles. The optimum bubble size can be created according to different feed characteristics. This is important in case of feed fluctuations.

Sep 1, 2012

By X. G. Liu

Bentonite is an excellent sealant mineral material because of its desirable swelling and self-healing characteristics, low permeability, sorptive qualities, and longevity in nature. A new type of water-swelling building sealant made from bentonite was studied in this paper. The building sealant is prepared by Na-base bentonite, vaseline and paraffin wax under different mass fraction of bentonite (which is 60%,65%,70% respectively). Under unrestricted state, some properties of samples were investigated. The volume expansion ratio at 24 h is 211%, 222%, 256% , and permeability coefficient is 2.86×10-8 cm/s, 4.15×10-8 cm/s and 4.78×10-8 cm/s respectively; low temperature flexibility of the sample (bentonite quality is 65%, 70% respectively) is good, and it does not flow heated for 2 h under 80?. The results of XRD and SEM indicate that bentonite is coated preferably by vaseline, and the spacing of layers of bentonite do not changed. The sample can keep full water swelling ability, and has good molding process. The test results prove that the properties of samples may reach the standard of building sealant.

Jan 1, 2014

By Kaustubh Joshi, Pradip, Beena Rai, Kesri L. Menaria, Venugopal Tammishetti

"Beneficiation of alumina rich iron ore slimes is a major challenge for the Indian iron ore industry. High alumina is deleterious for the performance of both blast furnace as well as sintering plants. Slimes generally contain 5 - 10% alumina, and hence despite assaying as high as 60% Fe, those are dumped in tailing ponds. The slimes are typically less than 37 microns. Selective flocculation of iron ore slimes using highly selective reagents is thus an option worth exploring. Our research is directed at employing state-of-the-art molecular modeling techniques for the selection/design of selective reagents for this separation. We have earlier reported our results on starch as a selective flocculant for iron ore slimes. In this paper, we present our results on the selective dispersion-flocculation of natural iron ore slimes using guar gum flocculant. With careful selection of various process parameters such as flocculant dosage, dispersant dosage, pH and settling time, we were able to obtain a concentrate assaying >66% Fe and <3.5% Al2O3 with an yield of 65 to 68% (recovery of iron values more than 70%) from a natural iron ore slime sample assaying 58% Fe and 7% Al2O3."

Jan 1, 2014

By G. Weingrill, H. Flachberger, J. Neubacher

The so called Bublon®-process is an innovative process for the controlled expansion of volcanic glasses such as Perlite and for thermal treatment of other minerals. In this manner, functional light fillers with astonishingly altered physical properties can be manufactured. In contrast to conventional Perlite expanding processes no fossil fuels are burned in order to achieve the expansion. Instead, the feed material is heated electrically mainly by radiation based on heat transfer from heating elements. The main advantage is the better controllability of the production process. Therefore, the heating elements are segmented along the flow of the particles, hence in direction of the ongoing expansion. Overheating of the particles, which ultimately leads to the destruction of the particle surfaces and consequently decreasing the quality of the expansion product, can be reduced significantly. Due to flow characteristics and settling behaviors of fines the lower particle size limit of the feed in this process is restricted to not less than 100 µm. Otherwise process instabilities are to be expected. Manufacturing industry demands light and fine hollow microspheres. Therefore, a proven cooperation between Montanuniversität Leoben and Bublon GmbH was formed to develop a new process called ‘Bublite’. This issue was addressed by changing the conveying principle into a pneumatically conveying system transporting particles from the bottom to the top of the kiln by the means of a drag flow. This approach makes it possible to handle the difficult flow patterns in the kiln and to control the retention time of the particles in the heat transfer zone. As a result, it is now possible to expand very fine Perlite particles into a high quality functional lightweight filler with a glazed-closed surface. The dependence of the polymer industry on importing this kind of fillers from overseas can be reduced by producing it close to sites of demand. Also the Perlite mining and processing companies benefit from this technology because the mine lifespan and the output of the processing plant can be increased.

Jan 1, 2018

By T. C. Rao

This presentation identifies how mineral (coal included) processing profession should look at the challenges (threats) being faced by mineral industry. Presently, the focus is more on supply and demand on minerals. In addition, the R&D activities in the chain of mine-to-metal are paying more attention (if not only on) the processes being adopted, development of new equipments and modeling and simulation. But the profession is grossly ignoring aspects such as impact of the processes on other resources, of the ways we extract, use and dispose them socio-economically and efficiently. A business model which may encompass all these dimensions are essential for the sustainable development of mineral industry and a possible approach in this direction is presented. To start with, for the sustainable growth and existence, the profession must be aware of the prospective impacts of their activities on critical factors such as ? political (changing government policies), geographical (environment, land, water and habitat), which have major bearing on the survival and growth of the industry. Mineral Processing professionals have to join hands with mining engineers to answer some relevant questions related to the impact of mineral industry on society. Mining can become economically viable only if mineral processing engineers come out with innovative solutions to reduce capital and operating costs. The solutions have to be adoptable and practically feasible so that industry looks at us for directions. In fact, we have to move towards beneficiation of nano particles striving towards zero waste. Some of the gaps in the knowledge of procedures being followed in the design and operation of processing plants are highlighted. Enhancing the knowledge base for solving unexplored possibilities, solutions to evolve sustainable development measures which demands innovation both at academic and practicing levels is the need of the future. Well-structured academic programmes are to be formulated so that the graduates of these programmes can make an effort to look at processes/concepts with a new insight and approach; the profession should excite the young brains with challenges. R&D funding agencies have to have a long-term perspective on mineral processing so that closer interactions between academic institutes, industry and R&D organizations are sustainable and that innovations are at least a few years ahead of needs of future challenges. Keywords: sustainable growth

Sep 1, 2012

By V. Hema

Granular materials are widely used in process industries, such as chemical, pharmaceutical, cement, food, detergents, and fertilizers. Mixing, blending, calcining, reduction, heating, and granulation of these materials are frequently carried out in rotating cylinders. In all of these processes, the mixing and segregation of these granular materials is important as this controls the secondary phenomena in the rotating kiln such as heat transfer to the material. A significant amount of work is available in the literature but to date these efforts have not been able to capture the important parameters affecting the mixing and segregation in rotating kilns. In addition, the range of parameter values studied so far is rather limited. Simulations of granular materials are based on either discrete elements or continuum models. The discrete element methods (DEM) combine semi-empirical models for the inter particle interactions with the equations of motion from classical mechanics to simulate the explicit paths of all granules in a rotary kiln, thus yielding realistic predictions of the mixing process. This approach is very demanding computationally, which strongly limits the number of granules and the number of revolutions in a simulation. Continuum models dispense with the discrete particles and can therefore be scaled up more easily. But the constitutive relations that serve as the foundation for continuum modeling are difficult to come by, and often only applicable to specific systems and conditions. Here we have chosen DEM simulation for investigating the mixing and segregation behavior of granular materials in a rotating cylinder. This work is directed towards demonstrating the capability of the prediction of the mixing and segregation behavior of granular materials in a horizontal rotating cylinder through discrete element simulation. Further the effect of particle size and rotational velocity on the mixing and segregation behavior is investigated. The simulation results are quantified in terms of mixing index, mixing rate, segregation index and percolation index. Keywords: DEM simulation, granular mixing

Sep 1, 2012

By S. H. Shahcheraghi

The four operational parameters including collector dosage, frother dosage, conditioning time and pH, are the most important parameters effective on the flotation kinetic. The present study has been done at the Miduk Copper Complex in the province of Kerman. The effect of operational parameters on the flotation kinetic of copper minerals were studied and analyzed, so the optimum conditions for flotation kinetic of copper sulfide minerals were obtained. Under the obtained optimum operational conditions, the recovery of copper sulfide flotation at the 95% confidence level was estimated to be between 92.76% and 95.48% and the copper sulfide flotation kinetic constant was estimated to be between 1.40 and 1.45 min-1. Results showed that the consumption of the X231 collector (O-isopropyl-N-ethylthionocarbamate) and the A65 frother (Polypropylene glycol) could decrease up to 35% and 50% respectively while the copper sulfide recovery increases about 1 up to 2% at the laboratory scale. Keywords: flotation kinetics, sulfide copper, optimization, the Miduk Copper Complex, response surface method

Sep 1, 2012

By Y. Rama Murthy

Around 90% of the chromite resources of India are concentrated in the Boula-Nuasahi Sukinda belt of Orissa state. In order to conserve these valuable ore resources strategically, several companies established chrome ore beneficiation plants in this region. The general beneficiation process in these plants consists of gravity unit operations such as Floatex density separator, spiral, wet shaking table etc. Most of these gravity circuits suffer huge losses of valuable minerals in the tailing. Any attempt towards decreasing these losses would not only increase the limited reserves in India but also make the economics of the operations more attractive. Apart from the liberation phenomena, in many of the operating plants considerable quantity of values are lost in the tailings, due to inconsistent feed quality, inappropriate selection of operating and design parameters. Mineral engineers in this regard have to play a proactive and continuous role to improve the performance of all separating units by modifying even small changes based on tests conducted in laboratory under controlled conditions followed by attempts to make necessary changes in the plant. For such improvements, accurate data collection and proper data interpretation followed by making necessary change which is implementable in an operating plant play a very critical role in performance of the circuit. Databank collected over a period of time under various conditions would also help in overcoming the future problems related to either variation in the feed characteristics or specific demand by metallurgical industries. The above concept was adopted in one of the operating chromite beneficiation plant at Sukinda. The approach adopted and practical problems encountered during the study were reported in this paper. The result of trial campaign has shown that, an overall product assaying 30.2% Cr2O3 from the feed (18% Cr2O3 ) can be produced to in single stage. The final discards of the process contain 12% Cr2O3. Keywords: chromite, chromite beneficiation, chromite losses, gravity concentration techniques, plant operating data bank

Sep 1, 2012

By Q. W. Jiang

This paper presents a new process for producing industrial magnesium sulphate using waste water from titanium white plant and magnesium oxide from calcinations of magnesite ore as raw materials. With the laboratory experimental equipment, the waste liquid and magnesium dioxide react effectively at ambient temperature and under atmosphere pressure. Via the press filter, a clear liquid predominately containing magnesium sulphate is obtained. It is further evaporated and crystallized by cooling, separated by centrifuge and dried. Consequently a high quality of industrial magnesium sulphate is achieved as the final product. In the course of process, as the majority of valuable component (SO42-) is recovered in the final product, most of impurities from waste acid is being removed into the by- product. With the simple operational process, it is possible for titanium dioxide plant to resolve the environmental problem completely and benefit from the industrial magnesium sulphate product as well. The filter cakes containing valuable elements such as Mg, S, Fe, Mn, V, Ti are by-product proposed to be used for manufacture of agriculture fertilizer particularly for peanut planting.

Jan 1, 2014

By M. Abdollahy

In this paper, the hydrophobicity of chalcopyrite particles produced with different laboratory mills has been studied; different grinding mechanism in themills made some changes in particles shape, Image Analysis (IA) method was used to determine the shape properties of chalcopyrite particles which are ground by a laboratory ball mill, rod mill and ceramic ball mill. The shape characters are stated in terms of shape factors such as circularity, convexity, roundness and regularity factor. Hallimond tube was used to float chalcopyrite particles followed by determination of critical surface tension of particles, this parameter used as a criterion to study the wetting behavior of chalcopyrite particles. The correlation between shape properties and critical surface tension of chalcopyrite particles showed that the hydrophobicity of chalcopyrite was affected by the shape. Investigations showed that the circular, round and more convex particles that produced with ceramic ball mill had lower hydrophobicity with higher critical surface tension (?c). The results also showed that the hydrophobicity of particles ground by ball and rod mills increased with the decrease of roundness, circularity, convexity and regularity factor of particles. Keywords: chalcopyrite, particle morphology, flotation, image analysis system, micro flotation method, hydrophobicity, shape properties

Sep 1, 2012

By Elisabeth Schmidt

The conventional Canadian oil sand processing, the Clark Rowe process, is associated with many risks for the environment and high energy costs. To recover the bitumen from the oil sand (tar sand), large quantities of water have to be heated up and mixed with caustic soda and the oil sand. During this process, tailings with stabilized clay colloids are formed and dumped in tailings ponds. To avoid these disadvantages, a new, non-aqueous extraction process is to be established. Organic solvents are used instead of water and caustic soda to mobilize the bitumen from the sand-clay mixture. Pressure filtration, washing and steam pressure filtration are part of the new concept. A mixture of organic solvents and the oil sand is first pressure filtrated in a nutsch filter until a saturation level of one is obtained. After the cake has been formed, the filter cake is washed with organic solvent to flush the bitumen loaded solvent out of the cake. The following steam pressure filtration mechanically and thermally removes the remaining volatile components of the solvents from the filter cake. The filtrates from the pressure filtration, the washing phase and partly from steam pressure filtration are subsequently thermally treated to recover the organic solvents and obtain a higher bitumen concentration in the mixture. This mixture is then lead to an upgrader to win synthetic crude oil (SCO). The recovery of bitumen in the conventional hot water extraction process based on the Clark Rowe process can, in highly optimized plants, achieve between 88 and 92 %. Variation of oil sand properties leads to an actual range of between 80 and 90 % of bitumen recovery. With the alternative process based on organic solvents, the bitumen recovery exceeds the recovery of the conventional process by up to 16 percentage points. The composition of the two organic solvents in the first step of forming a suspension with the oil sand is important. The aromatic component is crucial for liberating and solving the asphaltenes, which tend to flocculate. The order of the two components of organic solvents is also important in the washing step. The paraffinic component is essential to achieve successful steam pressure filtration with respect to fast steam breakthrough and a filter cake free from organic compounds, as a result of its lower boiling point. Keywords: oil sand, filtration, organic solvents, pressure filtration, steam pressure filtration, filter cake washing

Sep 1, 2012

There are interactions between different minerals from the same ore, minerals and grinding media, and the electrochemical conditions present in the system. Grinding in steel rod and ball mills is a common practice in minerals processing. It is accepted, that the electrochemical interactions between the grinding media and minerals in a grinding mill, influence the corrosive wear of balls/rods and the surface properties of the ground minerals. A complex massive sulphide, Cu-Zn, TAKNAR, Iran, was used for all the experiments. The aim of this study was to investigate the effect of grinding media (dry or wet) on the pulp chemistry and recovery of Cu and Zn in bulk concentrate. 1100 g of ore samples were milled, and mill products with d80=85 and 75 micron in wet and dry grinding methods were produced. Rougher bulk flotation experiments were performed with 550g ore samples, at 30% solids. SIPX in conjunction with Aero238 in 1:2 ratio (48 g/t), was used as mixed collector system, and copper sulphate (200g/t) and MIBC (20 g/t) were employed as sphalerite activator and frother. Lime and High purity Oxygen gas were used for adjusting pH at 8.5 and aeration. The results showed that, more positive pulp potentials were measured when the feed had been ground in a dry environment, and the difference in pulp potentials between the dry and wet ground feed was approximately 250 mV after the grinding stage. In dry grinding method, the recovery of Cu and Zn increased approximately 5 and 10%, respectively. In addition, in dry ground samples, the volume of middling and coarse particles (+100 micron) were more and Dry ground flotation feed had better agreed with using a mixture of collectors. After using copper sulphate, pulp potential increased about 50 mV in dry and 75 mV in wet grinding methods. Keywords: grinding media, pulp potential, Cu-Zn massive sulphide, bulk flotation

Sep 1, 2012

By Gurubasayya Swamy

This paper presents the consequences of modernization and expansion of process plant by implementing SAG and Ball Mill and Carbon-in-pulp technology at the Hutti Gold Mine. From the inception of the process plant, it has undergone many changes for the improvement. In the beginning, only gravity recovery of gold was carried out by using Pebble Mills and Strake Tables. Later amalgamation, Cyanidation and Zinc precipitation and finally Carbon-in-pulp gold recovery system was implemented. Grinding plant was modernized by implementing SAG and Ball Mill and Knelson concentrator for free gold recovery as a result, the production rate, rate of recovery, reduced man power, Modernization and expansion of process plant has also yielded in safe and smooth running of the plant. Keywords: sag and ball mill, cip, modernization and expansion, productivity, gold recovery

Sep 1, 2012

By N. N. Ngoepe

Positron Emission particle tracking (PEPT), which makes use of a radioactively labeled tracer particle, a positron camera and a tracking algorithm has been shown to be a viable method for studying flow properties in both the pulp and froth phases of flotation cells. Detailed velocity measurements of 300-400 µm glass beads were extracted to assess turbulence from velocity fluctuations in a micro flotation cell. The effects of particle speed and orientation at the instant of attachment events were studied. A minimum speed of 0.16 m/s was needed for a collision to lead to attachment. The most attachment events happen when the particle is directly in line with the inlet tube at 90o.

Sep 1, 2012

By N. R. Mandre

In the present work an attempt has been made to study beneficiation of low-grade iron ore associated with manganese clay by selective flocculation. The representative samples obtained for this purpose were initially subjected to chemical and mineralogical studies. The chemical analyses indicated 42.56 % Fe, 6.25% Mn, 8.72 % SiO2 and 13.60 % Al2O3 in the representative sample. The mineralogical analyses carried out under optical microscope showed that the ore mineral predominantly comprised of iron oxides and hydroxides along with manganese and silicate as gangue minerals. Prior to the beneficiation studies, the samples were subjected to settling tests. These tests were carried out by using poly acrylic acid (paa), poly acryl amide (pam) and guar gum (gg) as the flocculants. From these studies it was observed that settling rate of particles increases with increase in pH and a maximum settling rate of 0.23 cm/secwas obtained at pH 9 in presence of poly acryl amide. Further, the samples were subjected to selective flocculation studies using above-mentioned reagents. From these studies better results were obtained in the experiments carried out with poly acryl amide as the flocculant. Thus, it was possible to upgrade the iron content from 42.5 to 53%, with a recovery of 92%. However, 51% Fe with recovery of 87% and 50% Fe with recovery of 94 % was obtained using poly acrylic acid and guar gum respectively.

Sep 1, 2012

By S. H. Lau

Rapid 3D characterization of multiphase mineral particles in a variety of mineral processing applications is described, including: mineral liberation analysis, grain size, mineral exposure analysis, particle damage, and pore network structure for fluid flow simulation in heap leaching. While micro X-ray computed tomography systems (microCTs) have been used for many years, industrial adoption is limited due to a variety of reasons, including insufficient resolution, the general lack of imaging contrast to differentiate different mineral phases within a multiphase mineral particle and the lack of automated 3D mineral processing software. For example, resolution with industrial CTs and desktop microCT is of the order of tens of microns to a few microns at best, depending on specimen size and CT configuration. We describe a novel lab-based X-ray microscope, XRM, which overcomes these resolution and contrast limitations, notably as the industry is going towards finer grains and more complex ore bodies. Using lens-based optics and detectors (similar to its XRM counterpart in synchrotron beam lines), resolution of the lab based system is in the submicron range with contrast better than conventional microCTs. Hence, visualization, differentiation and segmentation of most mineral phases of interest to the industry are now feasible. Coupling these high resolution and high contrast tomography images with a suite of customized 3D segmentation algorithms and analysis software, applications in mineral liberation analysis for process control, particle damage assessment and other mineral processing applications can be achieved. This non invasive 3D technique which requires relatively little sample preparation is currently being considered for coal, industrial minerals, and base/precious metal ores, complementing existing microscopy techniques such as QEMSCAN and MLA for a variety of applications

Sep 1, 2012

By C. Kleine

Coal sorting with an x-ray-transmission (XRT) sensor has experienced a lot of development since first described by Jekinson et.al. in 1974. Powerful computers and increasingly sensitive X-ray scintillation counters enabled the development of high-performance sensor-based sorting machines. The first industrial installation of a belt-type XRT-sorting for coal is in operation since 2004. It is upgrading high quality coal from 1% ash to 0.7% ash for cathode production. In comparison to the high quality coal which is treated with a belt-type sorter, the chute type sorter has been successfully optimized for high volume coal treatment of lower quality coals. This project was funded by the German Environmental Fund (Project Nr.244444). In cooperation with the RWTH Aachen University and Isambane Processing, CommodasUltrasort(now Tomra Sorting Solutions) conducted extensive pilot test work under production conditions in 2010 for the destoning of power station coal at Arnot Power Station in South Africa. The experience gained during this pilot test phase led to an optimized, redesigned PRO Secondary XRT Chute sorter which is now in operation at a South African coal mine. This flexible semi-mobile modular destoning plant is treating a size range of -120 mm +30 mm at a throughput of 150 tph. The implementation of this plant not only reduces the ash content, abrasiveness index and sulfur content significantly, but also reduces royalties, water treatment and transport costs.

Sep 1, 2012

By Swati Mohanty

Spiral concentrator, which works on the principle of gravity separation, is widely used in the mineral industries for separation of solid particles based on the size and density. In the present study, CFD simulation of the flow profile on a laboratory scale spiral concentrator of height 2.29 m, pitch 0.435 m and width 0.17m was carried out. A single computational domain covering the entire spiral was considered. Volume-of-Fluid algorithm was used to track the interface and predict the flow profile. In the present study the Donor-Acceptor method was used for the calculation of volume fraction in the cell. Simulation results show that the velocity increases as the water flows down due to the convective force and gravitational force, but the viscous force acting in the opposite direction retards the flow. Thus the maximum velocity is attained at turn three at which the viscous force overpowers the other forces and further down the velocity decreases. Measured water depths along the radius of the spiral at various heights were compared with simulated depths, which were in good agreement. The simulated liquid phase velocity profile was used to carry out preliminary studies on the flow profile of solid particles of size 500 micron and densities 2600kg/m3 and 5100kg/m3, based on the Lagrangian model taking into consideration fluid-particle interaction.

Sep 1, 2012

By J. Lampke

The superior characteristics of iron ore pellets compared with natural ore and sinter are well known. Due to the higher grade and bulk density they show improved transport and material handling properties. While charging blast furnaces with pellets an increased productivity is realized through pellet?s uniform structure and composition. The increased productivity is caused by a high permeable furnace burden with a decreased coke usage via fuel injection and oxygen enrichment. Therefore, a narrow pellet size distribution and a minimum content -6.3 mm are necessary (Meyer, 1980). The required pellet size distribution can be achieved on the one hand by screening the fired pellets after the induration furnace and recycle the undersized pellets. On the other hand it is possible to produce high quality iron ore pellets with a high degree of sphericity, the important narrow grain size distribution ranging between 9 to 16 mm with high green strength directly in the pelletizing device. To produce high quality green pellets, possibilities and knowledge about adjustments of the pelletizing device are necessary. The paper presents a classification of state of the art pelletizing systems in accordance with the advantages of the pelletizing disc and pelletizing drum in issues like adjustability, green pellet quality, the recycling rate and the space requirement. By a systematization of the influences on pelletizing the common reliance of objectives on influence like pelletizing moisture, disc inclination, rotational speed, mass flow and rim height are given. A variety of industry-proven examples are shown, too. Keywords: Pellet, iron ore, pelletizing, pelletizing disc

Sep 1, 2012

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