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By S. N. Sahu

Attempt was taken in this study to explore the misplacement phenomena in binary mixture in solid-liquid fluidisation system. The binary mixtures of hematite and quartz particles at different sizes were taken. The closed size range particles were taken to minimize the size and shape effect in fluidization. As both the minerals have appreciable density difference, the separation of both minerals with closed size range has an advantage. The experiments were conducted in different permutation and combination of different sizes of binary mixture to observe the fluidization phenomena. The samples were taken at different heights in fluidized zones and analyzed the distribution of particles of both minerals. The fluidization characteristics were evaluated with respect to operating and design parameters. It has been observed that when the terminal velocity of quartz and hematite particles is same or near to each other, then misplacement is significant. In general, the segregation index value is near to one, complete segregation takes place whereas this value is near to zero, complete mixing takes place. The experimental data were used to find out the segregation index for different size ratios of quartz and hematite particles and the values are within 0-1. When the size ratio is 1 or less, complete segregation takes place whereas this ratio is within 1.0-1.4, partial mixing takes place. Similarly, when the size ratio is within 1.4-2.0, complete mixing takes place whereas this ratio is within 2.0-4.6, then it moves towards complete segregation in inversion manner. Keywords: particulate fluidization, misplacement zone, bed expansion, terminal velocity, mixing characteristics, segregation index

Sep 1, 2012

By Shounak Banerjee, Suresh Babu Dasari, Dharmendr Kumar, Shashank Pardhikar, Beena Rai, Venugopal Tammishetti

Recent increase in steel demand has led to the increased usage of high grade iron ores. During the mining, crushing and washing of ore, huge quantities of fines and slimes (<150 µm) are generated, majority of which is dumped into tailing ponds owing to their high alumina contents (~10-15%). Due to rapid depletion of high grade iron ore, it is the need of the hour to utilize low grade iron ore fines and slimes. These fines and slimes contain high iron values assaying 45-60% Fe. Dumping these valuable resources in ponds locks enormous land space and causes environmental hazards. The constituent minerals present in Indian iron ores comprise of hematite, goethite, gibbsite, kaolinite and quartz. Our research is focused on beneficiation of iron ore slimes through selective flocculation. We use density functional theory simulations to screen the reagents and perform experiments with screened reagents to determine the experimental conditions for effective performance of the reagents. Our studies revealed that reagents like starch, guar gum and carboxymethyl cellulose exhibit excellent selectivity in high alkaline pH range. However, the higher cost of alkali makes the process economically less attractive. In the present study, a commercial reagent from NALCO Water (Hi-Tex 83570) has been explored as selective flocculant for beneficiation of iron ore slimes in wide pH range (4-11). However, the reagent was also found to be the most selective in alkaline pH range only. Full factorial design of experiments was done considering three parameters namely, pulp density, flocculant dosage and settling time. Regression models were developed for yield, iron grade, alumina grade and iron recovery in the concentrate, using experimental results. Further parameter optimization was done to achieve high Fe recoveries and low alumina recoveries. The optimal parameters thus arrived at were validated with the experiments. We were able to achieve a concentrate grade of 60.0% Fe and 5.1% Al2O3 with 68.8% Fe recovery from a feed containing of 53.1% Fe and 8.9% Al2O3. The performance of flocculant Hi-Tex 83570 was also compared with reagents starch and guar gum.

Jan 1, 2018

By Neill Bartie, Jacques Eksteen, Sharif Jahanshahi, Shouyi Sun

The gradual increase in Cr2O3 levels of UG-2 ores has become a matter of concern for platinum producers in South Africa due to the formation of chromite spinels in melters. The effect of bulk FeOx/MgO ratio, Cr2O3, temperature and oxygen partial pressure on phase stability and composition in the system FeOx-MgOSiO2- Cr2O3-Al2O3-CaO has been studied between 1400°C and 1600°C using the drop-quench technique. An increase in temperature was found to result in a decrease in [Fe/Cr]spinel. An increase in bulk FeOx/MgO caused Mg, Al and Cr in spinel to decrease, forming more magnetite relative to other spinels. [Fe]spinel decreased and [Cr]glass increased with a decrease in oxygen partial pressure.

Jan 1, 2003

By Susanna A. C. Stadler, Chris Aldrich, Jacques J. Eksteen

"Slag foaming occurs in several pyrometallurgical processes. These processes include steelmaking in basic oxygen steelmaking furnaces and electric arc furnaces as well as various non-ferrous operations like sulphide smelting/converting and base metal slag cleaning. Although slag foaming in steelmaking processes has been extensively researched, little attention has been given to slag foaming in non-ferrous operations. Slag foaming phenomena are complex because often the system consists of three or more phases. With this in mind, factors previously identified as influencing slag foaming were investigated. These include the slag basicity, physical properties of the slag, namely viscosity, surface tension and density, the formation of particles due to undercooling of the slag and the FexO concentration in the slag.Slag foaming was investigated in a vertical tube furnace. The different slags were contained in alumina crucibles and bubbling argon gas through the molten slag induced foaming. The foam height was measured by using stainless steel probes and a voltmeter. The conductivity of the slags made it possible to measure the foam height from the position of the probes when the electrical circuit was completed. Slags were foamed at different temperatures to investigate the effect of solid precipitates.The effect of increasing FexO concentration was found to decrease the foam index due to lower viscosities, but higher surface tension depression appears to have led to increased foam index values at high FexO concentrations."

Jan 1, 2003

By Dave Deglon

"The Western Cape Mineral Processing Facility (WCMPF) is a collaborative educational initiative between the Departments of Chemical Engineering of the University of Cape Town, the University of Stellenbosch and the Cape Technikon. The primary objective of the WCMPF is to facilitate the education, development and graduation of suitably qualified engineering graduates and diplomates for the mining industry. The WCMPF consists of academics and Technical Officers in the Departments of Chemical Engineering of the three tertiary institutions. The Technical Officers are usually metallurgists, with several years of industrial experience. The main objective of the Technical Officers is to improve the practical education of mineral processing students. In addition, the Technical Officers are responsible for organising an annual mineral processing student field trip for students from all three tertiary educational institutions. In recent years the WCMPF has embarked on a number of additional initiatives aimed at improving the quality of mineral processing education. These include the development of several new pilot plant practicals, an initiative in pyrometallurgy, the introduction of novel ‘end to end’ or ‘integrated’ practicals and the use of mineral processing simulation packages to complement the practical training.The WCMPF has been functioning for well over a decade and, by virtue of this, might be considered a successful collaborative educational initiative. The WCMPF has played a key role in the education of over five hundred mineral processing graduates and diplomates. During this time period, the WCMPF has gained a body of internal knowledge which might be of benefit to other educational institutions, viz."

Jan 1, 2003

By M. Amani, A. Akbarinasab, M. Bazmandeh

The fourth iron ore production plant at Golgohar mining and industrial company consists a ball mill and wet medium intensity magnetic separators (3500 Guss). The ball mill product applies directly into MIMS and the MIMS concentrate directly transfers to the low intensity magnet separators (LIMS). The thickener is used for dewatering of MIMS and LIMS tailings. By sampling from streams of ball mill and separators, it was defined that the grade and iron recovery were 60% and 80% respectively while they would be 66% and 90% respectively based on the designing documentation. The average of P80 in the ball mill was 342 micron in a month that is coarser than optimized value. This problem was related to unsuitable operation of grinding. For optimization of grinding efficiency, the amount of charge volume was investigated as a variable. The measurements illustrated 32% charge volume. For increasing grinding efficiency, the charge volume was increased 1% and 1.6% in two stages. The results showed ball mill power draw average reached from 3650 kw to 4120 kw and the average P80 reached to 329 micron. All of parameters calculated about 35 day before and after change. Average of Ball mill feed iron ore grade before and after change was 49.24% and 50.32% respectively. This change caused an increase in efficiency of MIMS, where the enrichment ratio and concentrate grade increased 2% and 1.9% respectively. For increasing the iron grade of the MIMS concentrate; the orifice of the tail flow exit pipe changed from 4 inch to 6 inch and the concentrate grade increased 2%.

Jan 1, 2014

By B. Z. Wu

The flotation of low-grade zinc oxide ore which from Guizhou has been researched by sulfuration- amine method. The experimental result indicated that when pH of pulp was 11, good flotation index can be achieved by using sodium silicate as dispersant, mixed amine as collector, and the do-sage of sulfur sodium was 6kg/t, and the recovery of zinc can be heightened by using copper sulfate as activator and Hydroxamicacid as collector. When the zinc feed grade was 4.84%, the zinc concentrates with grade of 39.23 % and recoveries of 75.17 % were obtained by adopting this technics.

Jan 1, 2014

By Y. F. Li

Fengning ilmenite ore is a magnetic deposit in gabbro containing high phosphorus and low titanium, the main minerals in which are ilmenite, magnetite and apatite. The dissemination size of magnetite is so fine that even the percentage of -0.010mm level is up to 36.50%. The fine and vein magnetite are distributed in gangue and ilmenite, so the majority of the magnetite is difficult to be separated from the gangue. Ilmenite is difficult to be recovered by low-intensity magnetic separation even through fine grinding. In high-intensity magnetic separation of ilmenite, the gangue inter-growth with the magnetite and the Fe-containing silicates may be enriched in the concentrate, and the ilmenite of the concentrate will be reduced. Based on the processing mineralogy research, combined gravity-flotation process is suggested to recover the ilmenite. The method is also good to reduce phosphorus in the ilmenite concentrate.

Jan 1, 2014

By Y. Q. He

The methodology of active pulsing air separation is a new method for dry material classification. Especially, it is suitable to electronic scraps disposal and re-utilization. By studying the difference of drag coefficients of the particles moving through areas of varying Reynolds numbers, and considering the extra-mass forces acting on the particles in the active pulsing air field, models of the dynamic motion which particles follow were developed. A computer simulation was prepared that showed the traces of particles with different densities and/or diameters, but similar aerodynamic characteristics, as they moved through the turbulent flow, to modify and define the parameters of the models. The simulation was found to predict the observed results with artificial tracing spheres being separated by the laboratory equipment. The separation performance, as being affected by the particles, nature, the air velocity, the pulsing frequency and the air pattern, is discussed. In general, lower density particles are more responsive to variations in airflow velocity. In addition, an industrial scale active pulsing air separator was designed, and it provides a new and efficient method for resource re-utilization in China.

Jan 1, 2014

By E. V. Zelinskaya

"Mineral and industrial raw material mining and preparation make a negative impact on the environment. The main types of impact are the land resources gathering, soil and water balance disturbance, surface-water, underground space and atmospheric air pollution, as well as the vast amount of solid and liquid waste production. Considerable attention in recent decades has been given to waste recycling. The task is to maximize the use of both newly formed and accumulated solid and liquid wastes. The mining and mining and smelting enterprises industrial waters are a very promising source of secondary hydromineralic raw materials. They have high concentrations of not only calcium, sodium, but also, for example, lithium, rubidium, heavy non-ferrous metals. In general, unfortunately, we have to state that today there is no wide practice of extracting valuable components from waste enrichment, as well as processing of man-made waters to extract metals from them. The quantity of extracted components from underground, and furthermore passing waters, is insignificant. At the same time there is a tendency to increased demand for rare metals: Sr, B, Br, I. This is explained by their wide use in many industries. For example, the consumption of lithium products is steadily increasing. The obtained results showed that in the liquid phase in connection with high salt content and a significant difference in the macro- and microcomponents contents, conditions are initially created for the microcomponents selective isolation possibility. The identified conditions realization is most possible in such technological processes as cryotechnology, sorption and ion flotation. There is an urgent need to expand research in this direction and to recognize as a publicly important task the mining and industrial waste processing full-scale introduction into the practice of operating mining and processing enterprises and iron and steel companies.INTRODUCTION Mineral and industrial raw material mining and preparation make a negative impact on the environment. The main types of impact are the land resources gathering, soil and water balance disturbance, surface-water, underground space and atmospheric air pollution, as well as the vast amount of solid and liquid waste production."

Jan 1, 2018

By Sudhir Srivastava

India hosts a wide range of globally significant mineral resources, including four fuel minerals; 11 metallic minerals; 22 minor minerals and 52 non-metallic minerals. The country ranks among world?s top five nations for its commodity reserves of coal and iron ore. Interestingly, only small part of country&apos;s landmass has been explored that provides opportunity for future substantial mineral discoveries. India plans to double infrastructure investments to US$ 1trillion. Despite the challenges in infrastructure project implementation, mining sector remains a key driver of demand growth for commodities in the years to come with a good prospect to grow in future.

Sep 1, 2012

By Zoran S. Markovic

The extensive laboratory investigations were carried out in order to determinate behavior of sulphide and nonsulphide copper bearing particles during the flotation. The present ore sample were contained 0.55% Cu with 20.1% of nonsulphide copper in it and gangue material with higher contents of alumina about 19.07%. In this paper will be presented some results such as: effect of particle size, pH and applied collectors. The main goal was in application of collectors S-7518, as well as mixture of KEX and Z-96. Z-96 is a product from Chemical Industry Zupa Krusevac which was used as auxiliary collector in mixture with xanthates. The best results were done with this mixture in ratio KEX / Z-96 as 77/23 % in area of oxidized minerals flotation, but the collector S-7518 was achieved better results in sulphide mineral flotation. The S-7518 has better selectivity between copper minerals and pyrite comparing to mixture of KEX/Z-96 in mentioned optimal ratio. Flotation recovery and copper grade in concentrate were studied by flotation kinetics tests.

Sep 1, 2012

By A. Tolentino, J. Bravo, M. A. Corona-Arroyo, C. Quintero, R. Zarate, A. Lynch, L. Carillo

"This paper presents the performance of the flotation circuit of Minera Fresnillo PLC, Mexico. A plant survey was carried out on the lead banks and a size-by-size assay on the samples was conducted. The results indicate that the plant is treating fine particles in the flotation circuit. At least 30% of the particles in the feed are finer than 8 microns and that high amounts of Pb, Au, Ag and insolubles are in this particle size. It was also found that higher percentage of insolubles in the -8 micron particles are recovered in the final concentrate rather than being rejected in the tails. The presence of high amounts of insolubles in the concentrate is an issue of the company. The result of the plant survey provided valuable information for effective reduction of the insolubles in the concentrate and for plant optimization. The work conducted is part of the training of the students involved in a mine placement in the Alban Lynch Student Venture. INTRODUCTION Minera Fresnillo is one of the operating mines and the main contributor to the silver production of Fresnillo PLC group, the world’s leading producer of silver from ore. It is located in the mining district of Zacatecaz, Mexico, approximately 650 kilometers from Mexico City. The major minerals that make up the ore are galena, sphalerite, tetrahedrite, pyrargyrite, proustite, polybasite, pyrite and pyrrhotite. Minera Fresnillo has a capacity to treat 8300 tonnes of ore per day. The plant consists of semi-autogenous mill - ball mill – hydrocyclone circuit for primary grinding followed by silver-lead flotation then zinc flotation circuits. This paper reports the plant audit conducted in the silver-lead flotation circuit (Figure 1) of Minera Fresnillo. The circuit includes rougher, scavenger and two stages of cleaning. The tails from the scavenger goes to the zinc flotation circuit while the second cleaner yields the final silver-lead concentrate. The feed to the circuit has a particle size of 90% finer than 75 microns and generates a concentrate with grade of about 35% Pb, 5700 g/ton Ag, 16 g/ton Au and recoveries of 90% Pb, 90% Ag, 64% Au, respectively. Although the plant achieves their target concentrate grade and recovery, the concentrate also contains significant amount of insoluble materials which is about 18%. These insoluble materials consist of gangue minerals. The plant audit was conducted primarily to determine the possibility of further reducing the amount of insoluble materials present in the silver-lead concentrate."

Jan 1, 2018

By Xiong Dahe

In recent years many creative technologies are applied to SLon vertical ring and pulsating high gradient magnetic separators. SLon-2500 and SLon-3000 vertical ring and pulsating high gradient magnetic separators are created towards larger scale. Through optimizing the magnetic system and lowering the electric current density, their energy consumption is obviously dropped. New magnetic matrixes are developed to raise the beneficial efficiency of valuable minerals. Special SLon vertical ring and pulsating high gradient magnetic separators are developed which can treat coarser particles of 0-5 mm. Through these technology creations, the mineral processing efficiency of SLon magnetic separators is further raised and their processing cost dropped. Therefore, they have been found wider applications. SLon-2500 applied in Essar Steel of India. In 2007, Essar Steel did a test on its Kirandul hematite ore with SLon magnetic separator and got very good results. The feed grade is 59.77%Fe, after SLon one roughing and one scavenging, the total iron concentrate grade is 65.00%Fe and iron recovery 93.86%. In 2008-2010, the company bought 10 SLon-2500 magnetic separators to treat such iron ores. In 2010 the first SLon-3000 was applied to processing ilmenite. The magnetite-ilmenite deposit is located in Pan Zhi Hua, Si Chuan Province of China. The ore processing flow sheet is: Drum low intensity magnetic separator is used to take out magnetite, and then the SLon-3000 is used to recover ilmenite for roughing. The mags of the SLon-3000 are further cleaned by flotation. The SLon-3000 average operational results are: feed grade 9.52%TiO2, mags grade 17.43%TiO2, mags mass ratio 41.01%, TiO2 recovery 75.09%, non-mags grade 4.02% TiO2, non-mags mass ratio 58.99%. SLon magnetic separators Applied to treat 0-5mm limonite: The feed of SLon magnetic separator is usually 0-2 mm which needs to be ground by ball mill. As many Chinese iron ores are poor grades, if we can throw part of tails before grinding, the grinding cost will be greatly reduced. In 2010, a SLon-1500 and a SLon-2000 were specially built to treat 0-5 mm limonite. The feed grade is 26.51%Fe, mags grade 53.20%Fe, iron recovery 64.26, and tails grade 13.66% Fe. SLon-2500 applied to purify quartz. In 2009, a SLon-2500 magnetic separator was applied to purify quartz in Shan Xi province. Its feed is 0-1mm quartz which contains 0.15%-0.25%Fe2O3, the designed non-mags grade need to be less 0.08% Fe2O3. The production results of SLon-2500 non-mags are 0.05-0.06% Fe2O3, much better than the designed data. SLon applied in Si Jia Ying Iron Mine to recover hematite. Si Jia Ying is a big oxidized iron mine located in He Bei Province of China. In 2005-2010, a plant annually treating 10 million tons of oxidized iron ore was built in which 39 SLon magnetic separators are applied. The total flow sheet results are: Feed grade 30.44%Fe, iron concentrate grade 66%Fe, iron recovery 80%Fe, tails grade 9.65Fe%. SLon applied to recover specularite. Li Lou Iron Mine in An Hui Province of China built a plant annually processing 5 million tons of iron ore in 2010-2011. 25 SLon-2000 magnetic separators are applied to recover specularite. The total flow sheet results are: Feed grade 31.65%Fe, iron concentrate grade 65%Fe, iron recovery 80%Fe, tails grade 10.37%Fe. SLon applied in Da Hong Shan Iron Mine. Da Hong Shan Iron Mine is located in Yun Nan province of China. It treats 4.5 million tons of oxidized iron ore annually. 15 SLon-2000 magnetic separators are applied to recover hematite. The total flow sheet results are: Feed grade 35.61%Fe, iron concentrate grade 64.95%Fe, iron recovery 74.08%Fe, tails grade 15.55%. Keywords: SLon magnetic separator, iron ore, ilmenite, quartz, beneficiation

Sep 1, 2012

By O. Celep, H. Deveci, Ersin Y. Yazici, F. Ahlatci

"There are increasingly stricter environmental regulations imposed for use of cyanide leaching for the extraction of gold from ores. Alternative lixiviants to cyanide, preferably with low toxicity, have been extensively studied. Thiosulphate has emerged as one of the most suitable alternative leaching agent in place of cyanide due to its low toxicity and technical attributes e.g. fast leaching kinetics, high gold extractions from carbonaceous ores in particular. High solubility of most copper minerals in cyanide solutions results in low gold extractions due to excessively high consumption of cyanide. In contrast, low reactivity of copper minerals in thiosulphate solutions makes thiosulphate leaching potentially suitable alternative for treatment Cu-bearing gold ores. The extraction of gold/silver from a copper-bearing pyritic gold concentrate (62 g/t Au, 110 g/t Ag and 0.3% Cu) in thiosulphate solutions was investigated in this study. The concentrate is composed of predominantly quartz (25%) and pyrite (32.7%) as well as sphalerite (5.37%), galena (2.12%) and anglesite (1.13%). Other minor minerals are arsenopyrite, chalcopyrite, covellite and bournonite. Previous studies by the authors indicated that the concentrate did not respond well to cyanide leaching (i.e. 45-46% Au/Ag at 1 g/L NaCN). The effects of concentration of ammonia (0.2-1.5 M NH3), thiosulphate (0.1-0.75 M S2O3) and copper (0-20 mM CuSO4) on the extraction of gold and silver over 8 h. was investigated. Increasing the concentration of thiosulphate and ammonia substantially improved the rate and extent of gold leaching while high copper levels produced an adverse effect particularly at low concentration of thiosulphate (i.e. 0.1 M). Complete extraction of gold was achieved under suitable conditions. In contrast to gold, silver extractions remained consistently at low levels (i.e. 28%). These findings demonstrated that thiosulphate leaching could be used to achieve acceptable levels of gold extraction from the copper-bearing pyritic gold concentrate."

Jan 1, 2018

By Christopher M. Rule, Martyn P. Hay

"A methodology was developed in the mid-1980’s to predict plant performance from standard laboratory flotation tests. The methodology incorporates a flotation simulation program “SUPASIM” which translates flotation performance from bench-scale tests to full-scale plant. The technique is based on a simple, empirical kinetics model, and is tailored for use by the practical metallurgist. Kelsall’s unmodified equation incorporating two rate terms describing slow and fast floating components is used as the basis of the method. The flotation behaviour of an ore is described by a set of numbers, which can be compared in the evaluation of ore types, mineralogy and operating conditions. In so doing a precise relationship is developed between metallurgical performance in terms of grade and recovery and flotation kinetics.To date the performance of more than 20 flotation plants has been predicted, encompassing copper, lead, zinc, nickel, phosphate, pyrite, graphite, cassiterite, platinum and various slags. In three cases, plants have treated more than one type of ore. The method has successfully been used to predict and design four flotation plants using data generated from bench-scale laboratory flotation testwork. All have since been commissioned, and have performed as predicted. In the last year alone it has been used to drive flowsheet development for at least seven new plants in South Africa and the Americas. It is also being used to assist in the optimisation of existing operating plants."

Jan 1, 2003

By P. K. Fedotov

Annually at least 5% percent of world power consumption is involved in the process of ore dressing while ore processing technology. Such rate of energy consumption demonstrates the importance of a given process study in the human life-sustaining activity. Examining of interparticle destruction being under external stress pressure in ore responses this problem solution at the greatest degree. The technology of destruction in the roll press is of great interest. The use of the given equipment allows to save a significant amount of energy by means of the built-in ore destruction mechanism. Examination of stress-strain fields which determine the level of interparticle destruction between the rolls in the ore layer enables to specify both level of ore destruction and power consumption. The mathematical computer modeling for the deformable environment use based on the finite-element method (FEM) allows to carry out the given research. We use FEM solution for elastic contact problem for the most complete study of power consumption employed in ore and interparticle destruction. This problem solution allows also to examine energy consumption expenses spent for ore crushing in the roll press. Also we have identified the mechanism of ore in a layer of the particles under pressure roller press. It is established that high level of performance and reduction of energy consumption in interparticle destruction of ore in the layer due to the appearance of the gradient of normal stresses in contact of particles of mineral raw materials. The algorithm has been developed determining crushing product particle size distribution of fractured particles in the layer, using the Bond’s theory of crushing. The use of our FEM model reduces the time of equipment selection for new plant and at the design stage to reduce the risks of errors in the choice of roller presses.

Jan 1, 2018

By Yimin Zhu

This paper introduces the sixteen mappings and rules of mineral flotation and the subgroup, period etc in periodic table of chemical element to provide mineral flotation workers to refer in theory and practice research. the nine mappings and rules of mineral flotation and the subgroup, period are Saline minerals including the first main groups and collectors of aliphatic acid and aliphatic amines, Minerals including the second main group elements and collector of aliphatic acid, Hydrated ion of the second main group elements and quartz flotation, The floatability of oxidized minerals including the four main group elements, Organic acid including the fifth main group elements and wolframe, tin flotation collectors, The floatability of sulfide minerals including the fifth main group elements, Inorganic compounds including the seventh main group elements and mineral flotation regulator, Oxidized minerals including the forth Subgroup elements and organic flotation agents with phosphorus and arsenic, Oxidized minerals including the fifth subgroup elements and organic floating agents including the fifth main group elements, Minerals including the first subgroup elements and CN-, Sulfide minerals including the second subgroup elements and CN-, The effect of the highest N-valency inorganic acids or salts including p area elements of the third period in mineral flotation, Oxidized minerals including transition elements of the forth period and 3# flocculating agent, The floatability of minerals including elements of the sixth period, Element area of generating compositions and the collecting theory of mineral flotation and so and. Keywords: mineral flotation, periodic table of chemical element, subgroup, period, regulator, coordination chemistry

Sep 1, 2012

By V. E. Vigdergauz

Possibilities of the analysis of potential energy of bubble-particle interaction on the basis of extended DLVO theory are discussed. Interaction energies of mineral silica, coal and pyrite particles with contact angles from 20 to 100 degrees and air bubbles in neutral and alkaline solutions are analyzed. It is shown that for hydrophilic silica, the formation of particle-bubble complexes (either in the area of primary or secondary potential minima) is impossible due to the high potential barriers (from 6000 to 140000 kT)and low values of the attraction force. There is shown that for coal and pyrite particles the energy of interaction vs. particle-bubble distance strongly depends on pH value. Improvement of floatability of minerals by the hydrophobization of their surface by collectors leads to the eliminating of potential barriers and the formation of the stable complexes of minerals and air bubbles in the area of primary potential minimum. In addition, due to hydrophobization of coal and pyrite changing pH has practically no influence on the energy of interaction. There are discussed results of the numerical calculations of normalized interaction forces in particle-bubble systems on the nanometer distances for pyrite, sphalerite, and chalcopyrite at contact angles up to 85° in comparison with the experimental data. The values of adhesion force for hydrophobized particles of coal and pyrite to air bubbles are about 10-5 N, that indicates stability of the formed flotation complexes. Examples of using the long-range and high-energy effect of hydrophobic interactions for improving minerals floatability are discussed. There are illustrated minerals wettability changes induced by the adsorption of thiol collector and hydrophobic polymer. Possibilities of flocculation and flotation of mineral slimes due the polymer-collector hydrophobic interactions are shown. Keywords: bubble-particle interaction, contact angle, extended DLVO theory, floatability

Sep 1, 2012

By W. Pawlos

"The paper will present the methods of visual observation and recording of movement paths of coal grains of different physical properties in the paramagnetic liquid. The paths were recorded with a video camera in the working chamber by means of a specially constructed device, acting as a periscope, which were then transformed into digital images.Experimental movement paths were confronted to the paths obtained in a theoretical way by means of solving differential equations of movement. The outlet level of a grain of the same physical properties from the separator is a random variable with normal distribution which modal value is equal to the outlet level of a spherical grain, calculated from the solution of grain movement equations. At these assumptions it is possible to calculate the height of the passage from the separator working chamber to separate a given product with a given separation accuracy, measured by a probable error and to determine separation conditions."

Jan 1, 2003