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By Erico Tabosa

The turbulence characteristics and measurement techniques for agitated tanks are well established for liquid and liquid-gas systems. However, the literature shows that the overall energy dissipation rate (related to turbulence) is affected not only by air addition, but also by the concentration of solids. Unfortunately, there are no reliable measurement techniques for characterizing turbulence in a three phase (liquid-solids-gas) environmental system, which is the case in a flotation cell. Therefore, the effect of turbulence on flotation kinetics is very much one of conjecture. The aim of this work was to develop a sensor to characterize the degree of velocity fluctuation, which is related to turbulence, in a flotation cell operating with slurry and air. This sensor comprises a piezoelectric film transducer that converts mechanical to electrical energy. Hence, when the sensor deflects backwards and forwards an AC voltage is created. Flotation studies carried out using this sensor in a 3m3 Metso RCS cell processing a copper sulphide ore showed a highly turbulent impeller zone with transition to a significantly less turbulent zone in the upper portion of the cell. The transition region moves as the cell operating variables are changed, for instance the impeller speed, impeller size, air rate and feed solids concentration. Keywords: mechanical flotation cell hydrodynamics, turbulence characterization

Sep 1, 2012

By Carsten Gerold

The paper is giving an overview about successful operating Loesche Vertical ? Roller ? Mills (VRM) installations and summarises the main benefits of the dry compressive Loesche grinding technologies in Airflow- and Overflow-Mode. Some of these benefits are optimised energy efficiency of the grinding - classifying - circuits, increased mineral recoveries and decreased OPEX costs, at a parallel simplification of the process route. Within this paper the process values of the Loesche VRM are compared to existing or planned conventional grinding ? classifying circuits. Further advantages discovered in pilot trials and examples for new more efficient process route alternatives are given. The paper reports about production and pilot trial experiences obtained by crushing and grinding Iron Ore, Iron Ore Concentrates, Copper Shale, Copper Matte, Copper Slag, Titanium Slag, Tin Slag, Steel and Stainless Steel Slag with Loesche VRM.

Sep 1, 2012

By F. O. Milovich, V. A. Ignatkina, L. A. Samatova, E. D. Shepeta

"The aim of the research was to increase technological parameters of the flotation of finely disseminated scheelitecarbonate ore using selective reagent regime.In the studies the monomineral fractions of scheelite and calcite; samples of the scheelite-carbonate ore of the Primorsky deposit with the range of the carbonate module 3-65 were used. A carbonate module of ore is the ratio an initial assay of calcite to an initial assay of scheelite. Sodium oleate, iso-decyl alcohol, water glass, calcium chloride, soda or sodium hydroxide as flotation reagents were used. The flotation method in the Hallimond tube and in a mechanical cell, an adsorption method for study the kinetics of adsorption of oleate and isodecyl alcohol and its combinations on scheelite and calcite, IR spectroscopy including ATR to study the composition of surfacecompounds were applied. Selective reagent regime may include two ways - a combination of collectors or a modification of depressants of calcite and other gangue minerals. On one hand the combination of sodium oleate and higher fatty iso-alcohols of fractions C12-C16 in the rough scheelite flotation to reduce the flotation activity of calcite has been studied. On the other hand depression of calcite flotation by calcium chloride with water glass into rough flotation was used; modified the steaming cycle by Petrov's method applying change the concentration of water glass and other. Fatty iso-alcohols can adsorb on the surface of the calcite that reducing the adsorption of sodium oleate and floatability of calcite has been fallen. Their co-adsorbing with oleat on the scheelite surface were support the hydrophobization and flocculation of slime particles of scheelite. Flocculation of the particles of scheelite leads to increased up 3 times of the recovery of scheelite from the slime class, and calcite change up only 1.4-1.1 times it’s recovery.The growth of the carbonate module more than 11 is decreased the assay of WO3 in the scheelite concentrate of selection cycle."

Jan 1, 2018

By Y. X. Yang

Bottom ash is a solid waste stream in a Waste-to-Energy (WTE) processing plant during the combustion of the municipal solid waste (MSW). In the Netherlands, bottom ash contains typically about 18% metals originated from the MSW, and current industrial practice could recover about 10% metals through magnetic and eddy current separators. The remaining 8% as the finer particles is difficult to recover through current physical separation technology. Among various alternatives, vitrification is one of the promising options to immobilize the ash and recover the remaining metals. During vitrification a homogeneous glassy slag and a Fe-Cu based alloy were obtained. In the cur-rent study, the metal alloy recovered from the bottom ash originated from a Dutch Waste-to-Energy plant contains about 82 wt% Fe, 12 wt% Cu and 6 wt% other alloying elements and impurities such as C, S, P, Ni etc. The generated alloy does not have direct commercial applications, and separation of copper from iron-based alloy is critical to obtain the market value of both copper and ferrous constituents. To find a suitable processing route of this metal alloy, various alternative approaches have been considered for an efficient removal of copper from the alloy, and the focus in the present study was on the sulphide treatment at elevated temperatures of 1400 ~ 1500oC. The tested sulphide systems include pure FeS, FeS containing sulphide mixture (such as Na2S and Al2S3), pyrite (FeS2) mineral, ZnS containing sludge as an industrial waste. It was found that the carbon saturation of the alloy is proved to be an essential condition for a proper phase separation. The results showed that FeS mixed with Na2S, ZnS containing sludge and pyrite are effective sulphide systems for copper removal with a removal efficiency of 92% by using pyrite and 95% by zinc sludge at a S/Cu ratio of around 7 times of the stoichiometry. The copper content drops from 12 wt% to about 2 wt%. However, it is still difficult to remove copper completely from the alloy in a single step, and a multi-step operation is needed. The present research is expected to contribute both to the utilization of the metal recovered from bottom ash, and to the general recycling of steel scrap where copper removal from the steel scrap is a critical issue.

Jan 1, 2014

By Chris A. Fleming

"The ability to recover cyanide from gold plant tailings has been known almost as long as the cyanidation process has been practiced, but there has been little incentive to process tailings in this way in the past. With the development of technologies that make it possible to recover and recycle free or complexed cyanide directly from gold plant slurry tailings, which indicates, on paper at least, significant cost savings compared to cyanide destruction, coupled with the introduction of legislation to seriously limit the discharge of cyanide to the environment in most gold-producing regions of the world, many companies are evaluating the cyanide-recovery alternative.There is arguably an even more compelling reason for mining companies to consider cyanide recycling. With the growing storm of negative public opinion that the use of cyanide in the mining industry is attracting - following several highly publicized spills over the last couple of years - the time has come for the gold industry to demonstrate environmental diligence and stewardship in the use of this commodity that is so vital for their industry. There is no doubt that the widespread implementation of cyanide recycling will reduce the impact of the cyanidation process on the environment, both by reducing the risk of spills (with less cyanide being transported from manufacturing plants to gold mines), and by reducing the loading of toxic and nontoxic metals and ions in the tailings.This paper briefly discusses the pros and cons of the different processes that are available for the treatment of gold plant tailings to regenerate and recovery cyanide for recycling, and presents a techno-economic argument for the incorporation of this technology into many gold plant flowsheets today."

Jan 1, 2003

By Steven Wright, Sharif Jahanshahi, Shouyi Sun

"While there is a large industry based on recovering platinum group metals (PGM) from complex sulphide ores containing Cu and Ni, there is little information on the thermodynamics of the matte phase formed on smelting the ore and in particular the behaviour of Pt in the matte.The equilibrium between metallic platinum and industrial mattes was studied in a series of experiments where a small quantity of matte (5g) and platinum foil of 150 µm thickness (0.5 g) were equilibrated in magnesia crucibles at 1400°C under conditions where the oxygen and sulphur partial pressures were fixed.The chemical composition of the phases was determined from EDS analysis using a scanning electron microscope. Line scans were initially used to confirm that the foils had attained a uniform composition across their thickness. The composition of the matte was determined from analysis of an area of matte including the small metallic droplets and dendrites.The results of the equilibrium study are presented in terms of how the oxygen and the sulphur pressure affect the distribution of Pt, between the matte and the alloy foil (Lmatte/alloy). Other variables investigated were matte chemistry, i.e., the Fe content and the temperature. The activities of platinum in the mattes were calculated using a regular solution model describing the activity-composition relationship in the alloy."

Jan 1, 2003

By Samira Rashidi, Robert Dunne, Raj Rajamani

"High Pressure Grinding Rolls (HPGR) are known for more energy saving, better particle weakening and higher tonnage compared to semi-autogenous/ball mill circuits. These machines are scaled up based on the roll diameter. Therefore, studies in lab-scale HPGRs are always preferred because less weight of feed sample is required to run batch tests. The 50-hp laboratory-scale machine at the University of Utah is the first-ever lab-scale machine designed by late Prof Schönert, the inventor of HPGR. This 200x100 mm [DxL] HPGR is equipped with a robust data acquisition system, which enables running steady state tests using a feed sample as small as 6 kg to 12 kg. This paper presents the HPGR grinding study on two different categories of ores, one hard ore and the other soft. A test series has been performed to evaluate the energy consumption and the relation with size reduction on open multi-pass and locked-cycle HPGR circuits. The effect of feed size distribution and operating conditions has been investigated. Locked-cycle tests result in higher reduction ratio and higher rate of fines (100 mesh, 48 mesh and 28 mesh) generation when compared to open multi-pass tests. Data shows that scale-up trend lines stay consistent even when the circuit configuration and operating conditions are varied."

Jan 1, 2014

By Regis Texeira, Leopoldo Gutierrez, Vicente Hernandez, Caludia Vidal, Lina Uribe

"Molybdenum is currently the most important by-product of Chile´s copper mining industry. This mineral has gained international relevance over the years, because of its price. At mining deposits in Chile, copper and molybdenum are extracted together and then separated in a concentration process consisting of several flotation steps using sodium hydrosulfide (NaHS) as copper depressant. However, there are environmental issues related to the potential emisions of toxic hydrosulfide gas and bad odours, which affects nearby communities and suppose a risk for operators. This problem has led to the need for development of new technologies to eliminate the use of NaHS in the process of selective flotation of Cu and Mo minerals. In this work, results of flotation tests in which lignin derivatives reagents are used to obtain the selective separation of Cu and Mo minerals by flotation are presented. In this technology molybdenite is depressed by the action of lignin derivatives (lignosulfonates), while copper sulfides remain hydrophobic and float. The use of lignin derivatives in the selective flotation of copper molybdenum minerals represents a non-toxic alternative to NaHS.INTRODUCTIONSeparation of copper sulfides from molybdenite is commonly achieved through a two-stage flotation process. In the first stage the collective flotation of copper sulfides and molybdenite is promoted to generate a collective concentrate which is then treated in a second stage with sodium hydrosulfide (2.5-3.0 kg/t NaSH) to depress copper sulfides flotation without affecting the flotation of molybdenite. As a result a copper concentrate with 30-35% Cu, and a molybdenum concentrate with 50-52% Mo are generated. Although this process is widely used at industrial level, environmental issues related to the risk of H2S generation and bad odors have always been a concern. Thus there is a need in the industry for a more environmentally friendly process to separate copper sulfides and molybdenite."

Jan 1, 2018

By D. Izerdem, S. L. Ergun

"Beneficiation of the finely disseminated valuable minerals has been an important issue in the mineral processing field for decades. Treatment of the fine materials becomes difficult with using traditional gravity concentration equipment. To investigate particles behavior in a commonly used conventional gravity concentration equipment, a comprehensive study was undertaken in a plant, which only consists spiral concentrators as concentration units. Spiral concentrators require relatively coarse material to effectively concentrate valuables as well as offering greater simplicity for especially higher grade feeds. In the current work, chromite ore (d80 = 290 µm) was treated using spiral concentrators and the performance of spiral concentrators was examined. The design of the separation circuit comprised of rougher, cleaner and scavenger stages. The resultant fractions produced by each separation unit and feed samples were analyzed to identify the particle sizes, mineral liberations and chromite content. Grade and recovery comparisons were presented in size-by-size manner and the separation tendency of the particles were determined in varying feed rate conditions. The overall results indicated valuable mineral loss of the plant and alternative suggestions were pointed to reach the target values.INTRODUCTION Spiral concentrators are simple low energy consuming devices, which are generally used for pre-concentration of the minerals. They are cost efficient equipment separating minerals mainly based on density differences of the minerals. The adjustable splitters remove the concentrate as the remaining stream continues to move down the spiral. Separation on a spiral is achieved through a combination of forces that act on particles as they move down the trough of the spiral. The main forces known to act on the particle on a spiral are the gravitational force, centrifugal force, hydrodynamic drag and Bagnold force (Atasoy and Spottiswood, 1995; Burt, 1984). Since the classification in a spiral concentrator depends on particle specific gravity and size, the operation of spirals can be analyzed using size recovery or partition curves (Bazin et al., 2014). Spiral concentrators possess multiple design parameters for a variety of applications. The design parameters that govern the performance of the spiral can be identified as the diameter, number of turns, slope, pitch and the profile of the trough. For an efficient separation on a spiral concentrator, the properties of the slurry flowing on a spiral, ore texture, percent solids and flow rate play important roles."

Jan 1, 2018

By D. Z. Wei

Amine collectors with different structures and length of carbon-chain have been widely used in oxide minerals flotation. In this paper, we synthesized one kind of binary amine, N-dodecylethyl- enediamine, and studied its flotation performance. From the results, we can see N-dodecylethylenediamine which has excellent frothability, is a new type of chelating surfactants. And it also has fine catchability to quartz and hematite. The recoveries of quartz and hematite increase with the augment of N-dodecylethylenediamine concentration. When the dosage of collector reaches 100g/t, the recoveries of quartz and hematite achieve 95.30% and 87.89% respectively. Meanwhile, the influence of pH on the flotation recovery of hematite is studied and test results showed that, as pH increases, the flotation recovery rises until pH=9. And the recovery reaches its maximum in alkalescence. The collector has better flotation capability to quartz than to hematite. And the maximum recovery of quartz is gained in alkaline media, which reaches 97.87%. Finally, the flotation mechanism of N-dodecylethylenediamine is discussed through the measurement of infrared spectroscopy.

Jan 1, 2014

By Kumar Ashish, Shukla Akhilesh, Kr. Rokkam Kiran, M. Sheeba, S. Sombhatla Sundar

"Purification of zinc leachate plays a predominate role in zinc leaching refineries, to produce impurity free cathode sheets. As a part of such purification sequences, copper cementation with zinc dust is the preliminary step, since the presence of copper will preferentially deposit during zinc electro deposition and has the effect of reducing current efficiency. The cake thus produced is being accumulated as an inventory, due to invariable market and leading to space constraints & hazardous ambience. Hence, a project has been taken up for in-house generation of copper sulphate solution through ammonical leach followed by solvent extraction process and utilizing it as an active promoter for zinc sulphide flotation in Hindustan Zinc’s own captive mines. Cold purification cake majorly contains copper (30-40%) along with zinc (10-20%) and cadmium (2%). Confirmation to the above statement, photomicrographs of purification cake also confirmed the major presence of copper in metallic or oxidized form. In present work ammoniacal carbonate leaching of purification cake followed by solvent extraction using diketone based solvent has been studied under the influence of various parameters viz., temperature, agitation, pulp density, ammonia, CO2 dosages, solvent concentration, and impact of w/s zinc on leaching and solvent extraction. Leaching kinetics determined based on shrinking core model. Chemical reaction at unreacted core was found to be the rate controlling step. The estimated activation energy was found to be 24 KJ/mol. Leached copper has been extracted by solvent extraction with a ß diketone based solvent and is stripped with sulfuric acid as concentrated copper sulfate solution. The above established R&D findings are successfully implemented in the Commercial plant with a treatment capacity of two tons of cold purification cake per batch. Till now 500 MT of Purification cake has been treated, and generated 6500 MT of copper sulphate (55 g/l Cu), with final Cu recoveries between 87-90%."

Jan 1, 2018

By S. F. Kaplan, A. S. Dolotov, V. N. Kovalev

"At this point in time, autoclave recovery (POX) followed by sorption cyanidation (CIL) is one of the most promising technologies for the efficient processing of refractory and double refractory gold-bearing sulphide rock. This hydrometallurgical technology requires the use of a large amount of water (up to 5 tons per ton of used concentrate), resulting in highly saline water with high pH (pH 9-11), high content of cyanides (up to 300 mg/l), arsenic compounds, antimony and a number of heavy metals. In order to determine the possibility of using recycling industrial water in POX-CIL technology, several batches of experiments were conducted (using the double refractory flotation concentrate of the Mayskoye deposit). Urban water with a chloride ion content of 10 mg/l was used during the reference POX-CIL experiment as the liquid phase of the ??? feed pulp. At that, gold extraction rate amounted to 89.4 %. A full cycle of POX(200 ºC)-CIL was carried out during the first part of the experiments; at that, fresh concentrate of the untreated recycling water with cyanide ion content of 95.4 mg/l, left after the completion of the previous CIL cycle, was used for repulping. It has been established that direct use of untreated recycling industrial water is impossible due to a sharp decline in gold extraction (preg-robbing) down to 79.5%. The presence of chloride ions, cyanide ions and other ligands in the liquid phase provides effective complexion formation for the recovery gold; complex gold compounds are quickly and firmly sorbed by the natural carbonaceous substances of the concentrate at the stage of autoclave recovery; they are virtually not cyanized onwards, and gold is carried over to the tailings. During the the second batch of experiments, recycling industrial water with cyanide and chloride ions' concentration of 500 mg/l each was subjected to the reverse osmosis desalination (up to 6 times in a successive order). After each desalting cycle, such water was used as the liquid phase of the feed pulp in POX-CIL. 6 cycles of RO desalination enabled the extraction of 86.1% Au (which is close to reference recovery). During the third batch of experiments, recycling industrial water was diluted with distilled water (2, 4, 16, 32, 64 times); after each dilution cycle, this water was used as the liquid phase of the POX-CIL feed pulp. Gold extraction after 64-fold dilution amounted to 82.6%. The results of the conducted researches show that the use of untreated recycling industrial water in POX-CIL hydrometallurgical technology is absolutely impossible due to a sharp decline in gold extraction. Even the 64-fold dilution with pure water is inefficient both from the perspective of gold extraction and of rational use of water. Reverse osmosis desalination solves the problem of water treatment except for the removal of cyanide ion, which requires separate reagent treatment of water."

Jan 1, 2018

Geopolymers are novel engineering materials with the potential to play a highly significant role in the transformation of the construction materials and building products industry in the push to-wards sustainable development. These materials are formed by activation of industrial aluminosilicate waste materials such as coal ash or blast furnace slag with alkaline solutions. Some mineral waste can also be used, either as fillers or as reactive components. The use of waste-based geopolymers results in significant (up to 90%) reduction in carbon dioxide emissions when used in cement replacement applications. In addition to the formation of conventional pre-cast products, these high performance mineral binders are ideally suited to use in the conversion or encapsulation of toxic waste, including radioactive waste, due to their chemical stability and resistance to acid attack. It is the aim of this paper to review recent developments on the science underpinning this ?green? technology, and to discuss the technical and commercial drivers governing the large-scale adoption of the technology. Some of the recent fundamental breakthroughs in the study of geopolymer technology at the University of Melbourne will be presented. Despite the complexity of this reactive sol-id-gel system, progress has been made in the development of a thermochemical reaction kinetic model that has been validated using both calorimetric data and synchrotron kinetic data. Geopolymerization is potentially a disruptive technology, so that it is normal to expect strong resistance from established companies in the construction materials industry. It is increasingly necessary that waste generating industries such as mining collaborate with industries such as construction that could utilize this waste. The world?s first full scale geopolymer plant utilizing waste and re-cycled material has been commissioned recently in Melbourne, Australia, so progress on commercialization will also be presented. The authors frequently present keynote lectures on geopolymer science and technology at materials science, ceramics and construction materials conferences. However, this interdisciplinary technology that is still in its infancy, deserves more attention in the mineral processing and mining industry in view of its potential use in the mining industry, and also in view of the importance of mineral processing techniques in recent advances in geopolymers.

Jan 1, 2014

By K. A. Natarajan

"Interaction with microorganisms results in significant surface chemical changes on minerals. For example, chemolithotrophs such as Thiobacillus ferrooxidans and Thiobacillus thiooxidans significantly alter the surface chemistry of several sulfide minerals such as pyrite, chalcopyrite, sphalerite and galena. Heterotrophic bacteria such as Bacillus sp. could alter the electrokinetic properties of oxide minerals such as hematite, alumina, silica, kaolinite and calcite. Microbe-mineral interactions could thus be beneficially utilised in mineral beneficiation as different from bioleaching. Microbially induced mineral beneficiation unlike bioleaching deals with interfacial phenomena at mineral-solution-bacteria interfaces and surface chemical changes are brought about at very rapid rates amounting to a few minutes resulting in mineral separations in an aqueous medium.In this paper, the role of acidophilic chemolithotrophs such as Thiobacillus thiooxidans and neutrophilic heterotrophs such as Bacillus polymyxa in the beneficiation of sulfide and oxide minerals is illustrated. Mechanisms of bacterial attachment on various sulfide and oxide minerals are outlined with respect to the influence of bacterial interaction in bringing about mineral surface hydrophobicity or hydrophilicity. The role of bacterial cells as well as metabolic products such as bioproteins and exopolysaccharides in significantly altering the surface chemistry of sulfide minerals such as sphalerite and galena and oxides such as hematite, alumina, silica and calcite is discussed with probable mechanisms. Possibilities of generating mineralspecific bioreagents are outlined with respect to bacterial adaptation to mineral substrates."

Jan 1, 2003

By J. Vilcáez

The copper extraction yield from thermophilic bioleaching of chalcopyrite depends on temperature, pH, and the oxidation-reduction potential (ORP), as well as the activity of the microbe used. We studied copper extraction yields obtained from chalcopyrite with three thermophiles, Acidianus brierleyi, Sulfolobus metallicus, and Metallosphaera sedula, under various pH and temperature conditions and with different initial amounts of ferric iron. The results indicated that the capacity of each thermophile strain to leach iron as Fe3+ differed, which affected the influence of pH, temperature, ORP, and microbial activity level on the yield of copper. Microbial activity can cause ORP to be close to the critical value (450 mV) at which copper extraction at 65 °C can be higher than that at 80°C. An initial pH of 1.5 retards the precipitation of jarosite, allowing temperatures as high as 80°C to result in copper extraction yields close to 100%. However, if a thermophile with a poor capacity to form Fe3+ is employed, 100% copper extractions can also be obtained at pH 2.5, because ORP is low as result of low amounts of Fe3+ in solution. Optimum temperatures for the growth of thermophiles did not always mean high copper extraction yields. Conversely, high biomass concentrations depending on the capacity of the thermophile strain to leach iron as Fe3+, can result in excess Fe3+ in solution, leading to the precipitation of large amounts of Fe3+ as jarosite. The bioleaching capacity of A. brierleyi was reduced or suppressed when insufficient initial Fe3+ was pro-vided to trigger the leaching reaction, whereas S. metallicus and M. sedula were less sensitive to the initial availability of Fe3+. This result confirmed that a direct enzymatic attack on the mineral surface could initiate the leaching reaction, but later ORP governed the leaching rate of chalcopyrite.

Jan 1, 2014

By T. C. Sun

Two wasted activated sludges (WAS), from an industrial wastewater treatment and a sewage treatment plant respectively, and 7 collectors are used to investigate the feasibility of air flotation thickening of WAS by adding the collectors used in mineral processing. The collectors experimented include straight chain fat acids with different chain length, sodium oleate, alkyl sodium sulphonate, sodium dedecylsulfonate, and dodecylamine. The results show that the thickening efficiency varied depending on different collectors. Of the collectors experimented, dodecanoic acid and dodecylamine are best collector for thickening both sludges.

Jan 1, 2014

By M. Naymanbayev

The characteristics of the mineral composition of ores and valuable set of components: the technology of processing depending on the type of mineralization, the nature of the impregnation of ore minerals and their composition have been considered. There have been given technological schemes for processing concrete objects. The analysis of fitness fields for industrial development (degree of scrutiny, the effectiveness of developed enrichment and hydrometallurgy technology) has been provided.

Sep 1, 2012

By I. A. Podkamennyi, O. E. Kovalchuk, G. P. Dvoychenkova

"Using the methods of electron microscopy and IR spectroscopy, mineral components in the run-of-mine kimberlites and on the surface of diamonds were identified. The mechanism and sequence of mineral formation on the surface of diamond crystals were established. Systematization and classification thereof were undertaken for the first time ever.INTRODUCTION The high content of diamonds sized -5 mm in the kimberlite ores of Western Yakutia determines their processing depth in the size class 0.5 mm and finer [1, 2]. These diamonds are recovered by grease and froth separation based on the natural hydrophobic properties of the crystals. When refractory altered kimberlite ores are fed into the industrial process, the performance of grease and froth separation of the diamond ore greatly deteriorates. [4, 10, 15, 17]. Altered kimberlites are known to contain up to 90% of secondary minerals. This reduces by up to 40% the recovery of diamonds by grease and froth separation. [6].Diamond crystals from the grease and froth separation tailings were investigated. On the surface of the examined diamonds, hydrophilic mineral formations were identified, responsible for reduced recovery by physicochemical separation methods [3, 12, 18]. The aim of this study was to identify and describe the relationship between the composition of kimberlite ores and mineral formations on the surface of diamond crystals in order to systematize, classify, and then develop methods of removal in grease and froth separation processes. MATERIALS Following materials were examined in this study: - kimberlites of various material composition, - resulting slimes, - diamond crystals from kimberlite ore processing products."

Jan 1, 2018

By B. Das

The separation of iron values from a typical Indian iron ore slimes containing 57.2% Fe, 5.81% SiO2 and 7.05% Al2O3 by wet magnetic separation and selective magnetic coating is investigated. The iron phases, which are mostly paramagnetic in nature, have been coated with magnetite or colloidal magnetite in presence of surfactant by manipulating the surface properties of the minerals. The studies have indicated that an iron concentrate containing 62.32% Fe with 66.5% iron recovery can be obtained at medium magnetic intensity of 7.8 kG which is much less compared to normal magnetic intensity of 13 kG to14 kG required for hematite-goethite separation. The performance of this technique with respect to both grade and recovery is superior to conventional magnetic separation or flotation of iron ore slimes.

Jan 1, 2014

By G. H. Li

Preparation strontium carbonate with celestite concentrate by flotation is studied by agglomeration-reduction roasting process. It is shown that, the drop strength of green pellet is greater than 4 times?(0.5m) -1 under the balling conditions of moisture of 9% and time of 18~20min. Lignin xanthate obviously improves the ballability of the celestite concentrate due to the increase of surface hydrophilicity, therefore, the balling rate is increased, as well as green ball strength. The drop strength of 7 times?(0.5m) -1 can be obtained when the lignin xanthate dosage is 0.5%~1%. Reduction roasting with anthracite shows that the SrSO4 conversion is 82%~83% for celestite concentrate pellet, under the optimal conditions of roasting temperature of 1100~1150? and time of 30min, and it is 10% higher than conversion of celestite lump under the same conditions. The strontium carbonate are prepared after roasted pellets are leached, purified and carbonated, and the SrCO3 content is higher than 97% , while the content of CaCO3 is less than 0.3%.

Jan 1, 2014