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By Moris Fresko, Julia Sun, Charles C. Golembewski, Vytas Svalbonas

"A history of mill strain gaging at Metso is presented. The output of these strain-gaging programs is compared with calculated stress ranges from different finite element solutions. These comparisons expose the amount of approximation that exists in the analytical solutions, starting from geometry, and material properties, and ending with different forms of internal load models. The influence of strain gaging results on mill design and analysis practices is also discussed. While these instrumentation programs are valuable in identifying areas of high stress in mills, and locations of stress concentration factors, they are by no means extensive or comprehensive enough to verify general internal load models. The vast majority of the programs were aimed at getting additional data about potential failure points, rather than describing overall mill stress behavior. This is especially true since the more recent gaging programs have not included the difficult task of gaging the mill rotating structure interior. This paper tries to avoid the novice path of leaping to general conclusions on the basis of insufficient data."

Jan 1, 2014

By V. Sheikhzadeh, M. Saghaeian, R. Hejazi, M. Zare

High Pressure Grinding Roll (HPGR) plays a major role in increasing specific surface area of iron ore concentrate for producing pellet feed. HPGR grinding mechanism implies that material be compressed between the two rolls, therefore layer of material must be able to resist required pressure for achieving suitable grinding conditions. In this study for determining a simple relationship between material pressure resistance ability and HPGR main design parameters, piston press tests were performed on different iron ore concentrate samples along with HPGR Blaine increasing tests. Piston press tests results showed that by decreasing moisture content, material pressure resistance increased and in constant moisture content this parameter will change based on material specifications. HPGR Blaine increasing tests results showed that by decreasing moisture content, HPGR specific throughput and working gap increased and in constant moisture content this parameter will change based on material specifications. For all of the studied samples at worst condition, we got the results including: HPGR delta gap equal to zero, specific throughput lower than 200 ts/hm3.According to the tests results, HPGR Applicability Index (HAI) can be introduced at four different class types from 1 (weak) to 4 (excellent). This index determines achievable specific throughput and possibility of using HPGR according to material specifications, i.e. for HAI 1-4 the pressure resistance is <90, 90 to<125, 125 to <150 and = 150 bar, respectively. Similarly for HAI 1-4 specific throughput is <200, =200, =220 and =250, respectively. So based on design moisture content, if concentrate HAI is 3 or 4, HPGR is a correct choice. For HAI 2, HPGR can also be used. But for a material with HAI equal to 1, HPGR is not a good solution. As a result in order to apply HPGR for HAI 1, material condition such as moisture or slime content should be decreased.

Jan 1, 2018

By V. Yu. Ivanov, A. I. Yuryev, L. S. Lesnikova, M. S. Datsiev

"The Talnakh Concentrator was put into operation in 1981 using a direct selective process to produce copper, nickel and pyrrhotite concentrates.In 2001, a novel selective-bulk-selective (SBS) technology for the concentration of massive sulfide ore was implemented, that allowed to increase the valuable components recovery into target concentrates with feedstock grinding coarser than before. In 2003-2005, the process upgrading included the differentiated processing of nickelpyrrhotite products recovered at the different concentration stages and made it possible to significantly enhance the contrast of the pentlandite and pyrrhotite flotation properties and to simultaneously increase separation of polymineral intergrowths.The next stage of the PD concentration complex development is the Project ""Talnakh Concentrator Reconstruction and Technical Upgrading"" to raise its capacity by half. The project has three Phases.• Phase 1. Pilot startup was carried out in January 2015 following the installation of new OK-100 TC flotation machines, manufactured by Outotec.• Phase 2. The introduction of a new technology developed by the Polar Division specialists launched in mid-2016. The new technology is based on maximization of iron and sulfur removal into tailings and maintenance of non-ferrous and precious metals losses at the same level.After the realization of Phase 3, the annual capacity of the Talnakh Concentrator will raise by another ~ 40% at the expense of processing cuprous and disseminated ores currently being processed by the Norilsk Concentrator.By 2023, due to upgrading of the PD production facilities the emissions to the atmosphere will reduce by 75%.Polar Division of PJSC MMC Norilsk Nickel (PD) searches for the ways to solve its environmental issues. Thus, in 2016, the Nickel Plant was shutdown and a new flowsheet was introduced at Talnakh Concentrator. It resulted in the reduction of sulfur specific amount sent to pyrometallurgical processing as a component of the concentrates.The Talnakh Concentrator was put into operation in 1981 using a direct selective process to produce copper, nickel and pyrrhotite concentrates.In 1981, its design capacity for processing of Cu-Ni ores from Oktyabrsky and Taimyrsky Mines did not exceed 3 million tons per year.In 2001, a novel selective-bulk-selective (SBS) technology for the concentration of massive sulfide ore was implemented at the Talnakh Concentrator, that allowed to increase the valuable components recovery into target concentrates with feedstock grinding coarser than before."

Jan 1, 2018

By Áureo Del Vecchio, Lídia Dely Alves de Sousa, José Pereira

The potassium demand for agriculture purposes has increased in Brazil, which has great deficit of internal demands. Potassium-rich rocks have been used as fertilizers as technological alternatives for agriculture aimed to reduce the amount of chemicals and the sector dependence for such products. Vermiculite tailings from União Brasileira de Mineração - UBM, at Santa Luzia - PB, was studied aiming their application in agriculture by potassium release. The sample was analyzed by XRF and XRD; studies on release kinetic with particles smaller than 2 mm added of organic acids (citric and oxalic) at 10-2 mol/L concentration; samples were analyzed by XRD after kinetic assays. The work was conducted using a shaker incubator at 300-rpm agitation and time variation to better understand the potassium availability in the ground. Results show the presence of K2O at 3.46% concentration. Citric and oxalic acids increased the release speed to almost the same level with speed coefficients (k) of 2.61x10-2 h-1/2 and 2.55x10-2 h-1/2 respectively. In statistical terms for both acids, the linear equation represents more than 99.0% of the experimental assays. Stonemeal was applied to banana seedlings in experiment conducted in a greenhouse. The use of vermiculite tailings in banana seedlings promoted potassium absorption, which influenced its growth. The amount of potassium liberated from vermiculite tailings could be used as a long-term alternative to fertilizers in agriculture cultures.

Jan 1, 2014

By H. Mengbing, A. Potokin, A. Usov

"Revealed and analyzed in the study are the ways of significant perfection of specific characteristics of the equipment, such as use of high-frequency voltage transformation to create a charger; use of pulse transformers, with core made of materials with high magnetic permeability, in pulse generating circuits; as well as use of special ways to produce voltage pulses with a short front. The experiments have proved the possibility to adapt these technological solutions for electric-pulse installations, and suggested on this base is a strategy of further development and application of electric-pulse technologies. The different applications joint work schemes of voltage sources with two levels voltage and energy in electric pulse technologies are investigated. The possibility of increasing energy efficiency of destruction is shown."

Jan 1, 2014

By T. Wajima

"A novel carbonaceous immobilizing agent for heavy metal contaminated soil was prepared from rice straw using sulfur immersion and pyrolysis, and the lead immobilization in artificial contaminated soils using sulfur-impregnated carbonaceous material was estimated. The rice straws were cut to 1 cm pieces, and then immersed in 0.1 - 1 M K2S solution for 0 - 24 h to prepare sulfur-immersed materials. The immersed-materials were heated at 400 oC for 1 h in nitrogen gas to produce the sulfur-impregnated carbonaceous material by pyrolysis. The abilities of the product to immobilize lead from aqueous solution were examined to obtain the product with high lead immobilization ability. With increasing K2S concentration, the immobilization ability of the product for lead gradually increases and then above 0.5 M K2S those are almost constant, while 15 min is sufficient for the immersed time to obtain the product with high lead immobilization ability. The product prepared from material immersed in more than 0.5 M K2S solution for less than 15 min has a maximum immobilization ability for lead ion. The lead immobilization using the sulfur-impregnated product is sustainable due to the formation of leadhillite [Pb4SO4(CO3)2(OH)2] and anglesite [PbSO4]. The product can immobilize lead ion in various artificial lead contaminated soils. By mixing artificial lead contaminated soil with the sulfur-impregnated product, the eluted solution became neutral, and the eluted concentrations of lead ion dropped below the Japanese elution standard for soil.INTRODUCTION Soil contamination with heavy metals is a worldwide problem. Accumulation of heavy metals in soils affect soil ecology, agricultural productivity, quality of agricultural products, water resources, and serious health problems for human and animal (Raicevic, et al., 2005). In the United States, for example, approximately 63 % of the sites on the National Priority List (NPL) for the treatment of contaminated soils are contaminated by metals, and lead is the most common metal, found at 15 % of the sites. In Japan, according to a report by the Ministry of Environment, 43 % of the contaminated sites that exceed the environmental quality standards are contaminated by lead compounds. Soil contamination by lead compounds is also prevalent in other developed and developing countries where lead compounds are used extensively in industrial activities without careful contamination management. Lead is a ubiquitous heavy metal pollutant in soils due to their use widely. The primary sources of Pb contamination include industrial activities such as mining, smelting of metals, and the use of Pb-containing products such as paints, lead-acid batteries, bullets, gasoline and pesticides (Cao, et al., 2009). It can damage human nervous (especially children) and reproductive systems (ATSDR, 2007). The high concentration of Pb in the soil poses risks to human and animal health by the leaching of metals from the soil into water and the consumption of edible plants growth in the contaminated soil. Therefore, proper remediation is necessary to reduce metal availability in soil for protecting human health."

Jan 1, 2018

By L. S. Zhou

HermesTM metal magnetic liner (MML) has been invented and manufactured by China Metallurgy and Mining General Co. (CMMC). This paper describes its mechanism, structure, magnetic field distribution, application, economic benefit and safety performance. The 10 years? service life in Benxi Steel?s Waitoushan Mine, along with 6 years? technological analysis on its application in 5500mm×8800mm (diameter × length) ball mill in Anshan Steel?s Diaojuntai mineral processing plant, has proved its advantages such as super reliability, long service life, light weight, thin thickness, low noise and short payback period. It has also demonstrated its positive effects on the grinding process such as high productivity, energy-effective performance and low consumption of grinding media. It reduces labour intensity and improves working conditions, due to its easy installation, free maintenance and the fact that it doesn?t require fastening bolts or cause slurry leakage. It is de-signed scientifically in accordance with the varieties of processing lines, mill specification, ore type and grinding media, and has been applied in different grinding processes for magnetite, hematite, gold ores, nonferrous ores and other materials. HermesTM MML has three types of products: General, Composite and Heavy-duty. They are designed to meet the requirements from customers in China and abroad. So far, more than 400 sets of MML have been applied in ball mills with diameter rang-ing from 1500mm to 5500mm. It has become highly popular in American market recently due to its safe and effective performance.

Jan 1, 2014

By S. P. Nagaeva, A. V. Kuptcova, O. Yu. Poperechnikova

"The present paper contains study results of gold morphology and grain size distribution in flotation concentrates produced from original ore samples from deposits of different genesis. Pre-concentration methods were used with selective dissolution of rock minerals and mineral heavy medium separation to obtain statistically valid data on gold grain size and morphology in concentration products. Special attention is given to study of flash flotation concentrates that is mainly used for coarse gold, underextracted in gravity circuit. Analysis of geometrical optics has allowed to establish that during flash flotation gold grains more than 150 µm can be extracted from 10 to 35%, and in some cases single gold grains above 300 µm. INTRODUCTION Distinctive features of gold that have a significant impact, and in some cases, decisive influence on its recovery into saleable products are mineral shape, grain size and morphology of metal particles, paragenetic associations of gold. Peculiar feature of coarse gold is its easy extraction during grinding from associated mineral components like quartz, sulphide and other and almost complete recovery into gravity concentrates (Lodeischikov V.V., 1997). Morphology of native gold is so diverse that different gold grains are better extracted using different methods of concentration. Compacted and rounded particles are easily processed using gravity concentration but low cyanidable and hard to process using flotation. On the contrary, lamellar, flake, dendrite and capillary aggregates of high specific surface are easily cyanidable and under definite conditions it has strong floatability (Lodeischikov V.V., 1997). Flotation of gold-containing sulphide minerals and free gold takes place simultaneously during flotation concentration. In case of low-sulphide ores, native gold takes the basic load, having the high density (15.6 to 18.3 g/cm3, for pure gold – 19.3 g/cm3) it has limited size and morphology for successful flotation. It is known that flake gold and fine-grained gold up to 0.1 mm are easily extracted (Lodeischikov V.V., 1997). Authors of the present paper performed a study of gold granulometry and morphology in flotation concentrates produced from gold-containing ores from two deposits of different types: gold-copper oxidized hematite ores and low-sulphide gold-quartz ores. Ores are different by both host rock composition, mineralogical and petrographic features, gold grade in mineral assemblage and morphology and size of precious metal. Common for both ore types is low-sulphide content and presence of free gold."

Jan 1, 2018

By Z. Naziemiec

Since several years in Poland a huge demands on mineral aggregates occur, for the reason of intensive development of housing and road industry, as well as industrial building. Limitations in re-sources of broken aggregates in Central and Northern parts of Poland cause, that both the non-waste production of aggregates with high quality and the production of alternative aggregates from recycling gain greater importance, nowadays. It entails increase in demands for crushing devices, which are easy and reliable in operating as well as inexpensive and enabling to obtain a good quality products. Jaw crusher, regarded as the most spread in Polish industry, meet these requirements, however, their crucial disadvantage is a large content of irregular grains in crushing products. Numerous investigations show, that the shape of grains is a significant feature of aggregates, which influences on durability and quality of produced concretes. The advantage of jaw crushers is their easy operation, low price as well as low amount of dusts (wastes) generated in comminution products in comparison to other types of crushers (i.e. hammer crushers).

Jan 1, 2014

By Gaurav Soni, Roe-Hoan Yoon

A first principle flotation model has been derived from the basic mechanisms involved in flotation. The model consists of a series of analytical equations for bubble generation, bubble-particle collision, attachment, detachment, and froth phase recovery. The model can predict flotation from both hydrodynamic and surface chemistry parameters such as bubble size, particle size, energy dissipation rate, ?-potentials, contact angles (?), etc. The model predictions have been compared with the results of a series of laboratory flotation tests conducted using mono-sized glass beads of different particle sizes and contact angles under different operating conditions. Some of the experiments were conducted using a 1:9 mixtures if hydrophobic silica and hydrophilic magnetite, so that the product graded could be readily determined by simple magnetic separation. The model predictions are in good agreement with the experimental results both in recovery and grade. A computer simulator developed on the basis of the model is capable of designing a preliminary flotation circuit on the basis of feed characteristics, e.g., size-by-liberation data, and the hydrodynamic information on the flotation cells to be incorporated in the circuit.

Jan 1, 2014

By Longjiang Li, Mao Jiang, Zhihui Shen, Guizhou University, Yin Pan

This paper aims to study the influence and action mechanism of collector Y-89 on the flotation of auriferous pyrite. The measurement to identify adsorption quantity, IR and XPS spectrum analysis and flotation experiment made on the pure mineral were conducted. The research results show that when the dosage of MIBC is 20 mg/L, and pH of 8, the dosage of Y-89 over 60 mg/L, the pyrite recovery rate is greater than 80%.And when the dosage of Y-89is 60 mg/L, dosage of MIBC 20 mg/L, the pH in a wider range (pH=4~9), the recovery is greater than 75%. When the pH is above 10, the pyrite is depressed and its recovery rate is found to be dramatically dropping. Adsorption quantity measurement also shows that the strong alkaline conditions inhibit the adsorption of Y-89 on the surface of auriferous pyrite. IR measurement indicates that chemisorption of Y-89 occurs on the surface of auriferous pyrite. XPS spectrum analysis indicates that without adding Y-89, oxidation reaction occurs on the surface of pyrite. But when Y-89 is added, the chemical environment of Fe on the surface of pyrite has changed. Such findings indicate that with Y-89, chemisorption occurs on the surface of auriferous pyrite.

Jan 1, 2014

By Ghislain Bournival, Seher Ata, Graeme J. Jameson

A common method to prevent bubbles from coalescing in a flotation cell is by the addition of surfactants, called frothers. The gas dispersion properties in a column were tested for solutions of 1-pentanol, tri(propylene glycol) methyl ether, and poly(propylene glycol) in the presence of sodium chloride. The dependency of surfactant on the gas holdup can be divided into regions. It seemed that for a sufficiently low concentration of surfactant, even a stronger surfactant could show a transition in gas holdup from constant/decreasing to increasing with concentration. This region, however, was not marked by a decrease in the average bubble size. In addition, PPG gave higher gas holdup values while averaging larger bubbles. On the other hand, sodium chloride mostly affected the gas holdup when the concentration was high enough to prevent bubble coalescence. Another parameter affecting the gas holdup was the superficial gas velocity. A linear dependency was found between the two under a bubbly flow regime. The current study showed that both surfactants and salt could slightly affect the influence of the superficial gas velocity on the gas holdup.

Jan 1, 2014

By Matti Kongas, Kari Saloheimo, Antti Remes

"The paper studies the control performance of the flotation process as a function of the measurement accuracy and sampling frequency of an on-stream XRF analyzer, using a simple dynamic model. An additional aim is to assess how the economical result of a mineral flotation process depends on the quality of process control based on the on-line elemental assays.An on-stream XRF analyzer measures the concentrations of slurry lines in a continuous cycle from several process points. The control performance depends on the analytical accuracy and sampling frequency of the concentration measurement. With a long cycle time, the state of the process changes before a new measurement becomes available. With short measurement times the statistical variance of the counted Xray pulses increases, increasing the random error in the analysis. In addition, the measurement accuracy depends on the concentration of the component to be measured from the slurry.To quantify the effect of analysis error and frequency to process control, a simple dynamic process model is created in the Matlab environment. Data from a copper flotation circuit is used as a test case. The process model comprises a first order reaction equation and the grade-recovery -relationship estimated from process data. The control was modeled using the control strategies implemented into a rule based advanced control system. The economical performance of the control was studied by calculating the overall net smelter return at various analyzer parameter combinations."

Jan 1, 2003

By S. Gerl

Since Schönert, 1980 a multiplicity of scientists have dedicated themselves intensively to the scientific investigation of wet grinding in agitated media mills. The achieved research results led to a clearly improved understanding of the comminution mechanism in wet operated agitated media mills and in consequence also to clearly more efficient machines. In contrast to this the standard of knowledge on dry grinding in agitated media mills is still very small. The practical experience from numerous plants shows however that the transferability of knowledge from wet grinding to the dry grinding regarding transport phenomena and comminution behaviour, influence of the operating parameters and also wear is very limited. In the industrial application above all the continuous mode of operation is preferred. The main problem which has to be solved in agitated media mills is minor the comminution itself, than rather the question of the trouble free material supply and material extraction as well as the cooling of the mill. The agitated media mill MaxxMill® offers an innovative concept to overcome the feeding and extraction problem with its rotating grinding chamber, the eccentrically mounted agitators as well as the eccentric flow deflector with integrated material supply. Because of the pneumatic extraction of the ground materi-al cooling of the milling chamber is not necessary. On a MaxxMill ® laboratory mill with a 5 litre grinding chamber volume extensive parameter studies were carried out to study the influence of operating parameters on the continuous dry grinding of quartz sand. The test were performed in a continuous single pass operation without classification of the final product. Apart from the influence of the throughput rate on fineness above all the influence of the agitator and grinding chamber speed as well as the grinding media size was examined.

Jan 1, 2014

By G. Unland

The sizing of crushers depends on the expected crushing forces. However, the crushing forces develop differently with every individual rock while it is compressed by the working surfaces of the crusher. For sizing, this compression process has to be characterized by the maximum crushing force. The maximum crushing force depends on the strength, shape and size of the rock, the amount and velocity of the imposed displacement of the working surfaces of the crusher on the rock and the conditions of the contact surfaces. From experience it is known that the strength of the material and, therefore, the crushing forces depend on the size of the specimen. This dependence is the so called size effect. The determination is based on compression tests. The force development is recorded during the compression of the specimen and for every individual test the maximum force is determined. The occurring maximum crushing forces of several rocks with the same diameter comminuted under the same conditions can be assessed by a mean value and a variance. The relationship between the mean values of the cross section related maximum crushing forces FAmax and the corresponding sizes d of the specimens can then be described by mathematical functions. They are derived from different approaches (phenomenological, statistical and statistical-physical methods). The phenomenological methods are subjective and yield functions depending on the assumptions of a person, whereas the statistical and statistical-physical methods are based on an evaluated function and the optimization of the parameters.

Jan 1, 2014

By Song Z. Guo

Calcite and magnesite are both carbonate minerals and their crystals belong to trigonal system. Flotation tests were carried out to investigate the flotation behaviors of calcite and magnesite. The test results show that the floatability of calcite and magnesite under different grinding environment had obvious differences. The floatability of calcite using sodium oleate as collector after dry grinding is better than wet grinding, but the floatability of magnesite after wet grinding is better than dry grinding. The XPS surface elements test and zeta potential measurement show that, wet and dry grinding process makes the distribution difference of surface anion and metal cation, then influence the floatability of the two carbonate minerals using sodium oleate as collector. Difference of the carbonate crystal structure and solubility properties was also investigated. Research shows that crystal structure difference of calcite and magnesite causes the difference of solubility, which can influence the flotation behaviors under different grinding environment. Keywords: carbonate mineral, crystal structure, solubility properties, flotation, surface character

Sep 1, 2012

The flotation behavior of kaolinite and diaspore using N, N-diethyl dodecyl amine (DEN12) and N, N-dimethyl dodecyl amine (DRN12) as collector have been investigated through flotation experiments. The mechanism of adsorption of two tertiary amine collectors on surface of kaolinite and diaspore were investigated by FTIR spectral, Zeta potentials measurements and calculation of molecular orbital energy. It has been found that DEN12 and DRN12 have stronger collecting power to kaolinite and weaker collecting abilityto diaspore than DDA. Kaolinite and diaspore in bauxite ores can be separated by using DEN12 and DRN12 as collectors at pulp pH below 8 and 6, respectively. The results of zeta potentials and calculation of molecular orbital energy indicated that the adsorption strength on kaolinite surface is in the order DEN12>DRN12>DDA and the adsorption strength on diaspore surface is in the order DDA>DEN12>DRN12. FTIR spectral analysis and Zeta potentials approve that the action between kaolinite and tertiary amine collector is strong electrostatic adsorption and that of diaspore is weak electrostatic adsorption in the range of pH 5~6.

Jan 1, 2014

By D. Saramak

"High-pressure grinding technology is considered as one of the most efficient techniques of ore comminution, especially in terms of energy consumption. HPGR devices has been utilized in many mining-related industrial sectors, including iron and non-ferrous metal ores processing (copper, platinum, gold), as well as cement and limestone flour production. Even though the technology well known (introduced into mineral processing circuits in 80’s), there are still examples of ineffective operation of HPGR devices. This is a result of improper application of HPGR into individual crushing circuit. The purpose of the paper was to analyze selected effects achieved in HPGR on the course and effectiveness of beneficiation operations. Investigations were carried out for copper ore, and investigative programme was run for different values of HPGR pressing force, as well as changeable ore characteristics (content of fine size fractions, material moisture). All crushing products were then treated in flotation process, in order to determine useful mineral recovery. Results of investigations show that HPGR operating pressure influences the metal recovery in proportional way, however too extensive pressure values have relatively lower impact on increasing of the metal recovery. Particle size distribution of HPGR feed and its moisture have lower influence on recovery level than HPGR pressure, but too extensive moisture content influences the higher energy consumption of the roller press, together with less effective comminution. The second aspect raised in the paper was a possibility to control and optimize the HPGR-based circuit. There were presented the proposed approach to adjustment of HPGR operating parameters that enables the higher metal recovery.INTRODUCTION The high-pressure grinding technology, invented and developed by Professor Schoenert in 70’s (Schoenert, 1979), is currently regarded as one of the most efficient methods of hard ore comminution. Since then the technology was introduced into raw materials treatment circuits in many mining and mining-related industrial sectors, including iron and non-ferrous metal ores processing (copper, platinum, gold), as well as cement and limestone flour production. Considerable number of works concerning modeling and optimization of HPGR operation were also presented (Daniel & Morell, 2004, Tavares, 2005, Saramak, 2012, Saramak & Kleiv, 2013). Nowadays high-pressure grinding rolls devices are considered as well know technology with over 500 sold machines, according to various sources."

Jan 1, 2018

By L. Li

Chemical composition, mineral composition, and iron occurrence state of main mineral are studied, Research of mineral processing technology is carried out according to ore features. The test results indicate, that through staged grinding-staged concentration process, the better separation index is up to 65.54%, iron preparation concentrate grade and 85.66% recovery with the fineness (-200 mesh) 45.88% in the primary grinding ore and the fineness (-200 mesh) 75.50%, in secondary grinding ore in the situation of best magnetic field intensity (roughing 0.2T and cleaning 0.15T).

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