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By Shailin Lalloo, Allan B. Nesbitt

A fluidised bed was exposed to high gravities by placing it in a centrifuge. The bed expansions were measured and compared with the bed expansions predicted by the Richardson-Zaki model (1954). The Richardson-Zaki model was found to predict effectively the fluidisation behaviour of defined particles in this increased gravity environment.

Jan 1, 2003

By C. Y. Wang

Based on Slurry Electrolysis, and combined with the problems of extraction antimony, lead and their separation from complicated antimony-lead concentrate, a series of tests have been done in this paper. Using Slurry Electrolysis to treat complicated antimony-lead concentrate, antimony and lead can be separated in one step. And 2# metal antimony can be achieved in cathode directly at the same time. Lead in concentrate is restrained still in the residue at the form of PbCl2. After converting the residue with ammonium carbonate and removing sulfur with kerosene, the high quality of lead concentrate (Pb is above 45%, S is below 15%) and pure sulfur can be achieved, respectively. The recovery of all in Slurry Electrolysis process is as: Sb 95%, Pb 95%, Ag 80%, S 60%.

Jan 1, 2014

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 C. R. Mambote

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

Jan 1, 2014

Electrochemical behaviors of synthetic and natural enargite in buffer solutions have been investigated using open circuit potential, stationary polarization and cyclic voltammetry as functions of solution pH, scan direction, scan range, scan rate and dissolved O2. The results indicate that the electrochemical behaviors of synthetic and natural enargite are very similar; solution pH, scan direction, scan range and scan rate have remarkable effects on the electrochemical behavior of enargite while dissolved O2 has little effect on the electrochemical behavior of enargite. The potential range in which enargite possesses the ability of passivation is from ?0.9 V to + 0.83 V vs. SCE. Enargite is most stable in neutral and alkaline solution around potential ?0.2 V vs. SCE. The main oxidation products on enargite surface in alkaline solution are Cu(OH)2 while the potential imposed on it is within the range of ?0.2 V to 0.33 V vs. SCE and Cu(OH)2 + S0while the potential applied is higher than 0.52 V vs. SCE.

Jan 1, 2014

By Y. F. Guo

Laboratory scale experiments were conducted to produce titanium-rich material from Panzhihua ilmenite. The results showed preoxidation with sodium salt additive especially for Na2B4O7 signif- icantly advance the reduction of iron in Panzhihua ilmenite. Acceleration mechanism of preoxidation with Na2B4O7 has been studied here. The maximum metallization of iron 92% can be obtained under conditions of preoxidation at 850? for 30 min and subsequent reduction at 1100? for 150 min. The rusting separation technique to reduced ilmenite has been further studied, obtaining titanium-rich product with TiO2 over 82% and the recovery of TiO2 above 97%.

Jan 1, 2014

By R. B. Shu

A moderate thermophilic microorganisms, has been isolated (45?) from a typical sulphide mine in the region of Mo Jiang located in the southwest of China. The culture has been used to extract copper from chalcopyrite concentrates obtained from De Xing copper mine. The majority of experiments were carried out in 300mL Erlenmeyer flasks containing 150mL volumes of mineral suspension. Effects of some variable parameters such as solids concentration, pH and the concentrations of inorganic nutrients on the bioleaching of chalcopyrite obtained from De Xing copper mine were investigated. For a given concentrate the most important factor affecting the fractional copper extraction was the size of the mineral particles. The overall rate of leaching was found to be limited by the area of mineral surface. The attack started in cracks and genetic defects and finally reached the whole chalcopyrite surface. As a consequence of this, the ore showed strongly cracks. The additive of ferrous sulfate increases the bacteria activity, but did not improve chalcopyrite bioleaching. The results indicate that the nature and relative proportions of the various minerals present have been shown to be important factors.

Jan 1, 2014

By F. A. V. Guimarães, A. M. Costa

"The moisture in sintering is a very important parameter for the performance of the process. It allows that the granulation takes pace in an efficient way making the water bridges between the bigger particles used as nucleus and the finer particles that perform the coating of those coarse particles. The formation of the micro pellets is extremely important to prevent loss in permeability of the bed in the sintering grate, avoiding excessive fuel consumption and producing a quality sinter. The aim of this project is to use some of the methodologies for determine the saturation degree on ores and coal to determine the optimal moisture for sintering. In the sinter pot grate series, 3 to 4 assays in a series of 10 are required to determine the optimal moisture for the process. The saturation degree curve test has shown that is really viable to use this technique to skip those tests and go directly to the series to determine productivity and the coke / anthracite consumption. In an industrial scale can be used to adjust the water addition in the conventional mixing methods used in the sintering plants to increase productivity in the process.INTRODUCTION Sintering Sintering is a high temperature agglomeration process in which iron ore fines are partially melted and bonded together using fluxes and a source of fuel, usually coke breeze. The agglomerated product, sinter, has improved metallurgical properties making it an ideal ferrous burden that enable the passage of hot gases in the iron-making blast furnace. The sintering process is normally carried out over three basic stages: granulation, ignition/sintering, and product sizing. In the granulation stage, iron ore fines (usually a blend of selected ores), sinter return fines, fluxes and fuel, and are mixed with water and micro-pelletised in a drum or disc before being introduced in the main granulation circuit. (Wang, Teng, & Wang, 2017)."

Jan 1, 2018

By L. A. Vaisberg

"Mining processing plants are the most high-performing industrial enterprises in the world economy system. Even at an average-scale mining enterprise, the grain-size separation equipment continuously processes 105 to 106 dissimilar mineral particles per hour. In separation by physical properties, their number increases by at least 10 to 50 times. Mathematical modeling of such a high flow of discrete particles is carried out using two different approaches: the discrete-particle and the phenomenological methods. The calculations demonstrate the possibility of handling big data when describing the processes of separation of granular material. INTRODUCTION The interest to the screening process and the process of formation of new screen designs in Mekhanobr is traditional since the moment of its foundation. It is symbolical that the first publication of the Mekhanobr proceedings in 1924 was the monograph dedicated to screens and screening products as such, which was the first one in the world at that moment. It was a book of Prof. L. B. Levenson, one of the founders of Mekhanobr, who headed the Technical Bureau of the Institute. Vibratory screening is the most mass process in the technologies of solid minerals processing, which determines significantly the energy demands of crushing and grinding cycles, and at some enterprises determines the quality of the final product, for example in case of crushed stone, coal or abrasive materials production. The general understanding and simulation of the process of poly-dispersed granular materials vibratory screening was developed at several conceptual levels taking into account the features of classification of materials with different size and density.Considering the real industrial processes of vibration screening, it shall be noted that at the sieve surface of the screen in the initial part of the deck the classification in a thick material layer (in natural conditions) occurs, which further transfers to a thin layer (free movement). In the process of screening of light minerals, for example coal or metallurgic feedstock, screening is mainly performed in the thick layer."

Jan 1, 2018

By Y. B. Zhang

China is rich in iron ore resources, but most of these ores are low-grade, polymetallic and refrac-tory ones. Furthermore, with the rapid development of chinese iron & steel industry, the comprehen-sive recovery of these ores is becoming more and more important. The tin, zinc-containing complex iron ores are typical polymetallic and intractable ones, and great reserves of them are found in China. At present, they have not been efficiently utilized. In this paper, based on the investigation of basic physicochemical properties of the tin, zinc-bearing iron concentrates, taken from a mineral processing plant, the mineralogy reason that these concentrates are so intractable and refractory is found out, using advanced microscopic testing methods, such as optical microscope (OM), Scanning Electronic Microscope (SEM), X-ray diffrac-tion (XRD), etc. It is found that the symbiotic relationship of iron, tin and zinc metallic minerals are very complicated, and magnetite in the concentrate is closely symbiotic or enwrapped by fine cassi-terite and sphalerite. So it is difficult to separate tin and zinc completely from the iron concentrates by simple regrinding and physical separation method. This investigation provides theoretical guid-ance for developing new approaches for utilizing these concentrates.

Jan 1, 2014

By Yang Zhao, Tao Xiu-xiang, Chen Song-jiang

"China is rich in low-rank coals that account for 45.68% of existing coal reserves in China. The clean and efficient utilization of low rank coals is of great significance for ensuring the effective energy supply and promoting economic development and environmental protection. In order to solve the difficult problem in flotation of low rank coal, it has become the focus of research in the related field that oily bubbles instead of air bubbles are taken as a carrier in flotation to improve the attachment efficiency and recovery of low rank coal. In this paper, low rank coal slime collected from Shendong mining area was used as the experimental material, and it focused on the characteristics of oily-bubble flotation process of low rank coal. Additionally, difference in conventional flotation and oily-bubble flotation was discussed. The induction time between air bubbles, oily-bubbles and fine low rank coal particles was measured. The results indicated that the induction time between oily-bubbles and coal particles was obviously lower than that of air bubbles. By comparing the foam height of air and oily bubbles, it was found that the amount of oily bubbles is less than air bubbles, causing relative low flotation rate of oily-bubble flotation at initial stage. Besides, the maximum foam height and half-life of air bubbles and oily-bubbles were measured respectively. The results showed that the stability of oily-bubbles was higher than that of air bubbles, which is benefit for the enrichment of concentrates. The clean coal water recovery of oily-bubble flotation is lower than that of air bubble flotation, which indicated oily-bubble flotation is lower in water entrainment. INTRODUCTION China is the largest energy consumer in the world, accounting for 23% of global energy consumption in 2016 and 27% of global energy consumption growth. Whereas coal is taken as the major primary energy source and its share of China’s primary energy consumption is 62% in 2016, in which the low rank coals, such as lignite, long-flame coal, weakly caking coal, and non-caking coal, accounted for about 50% of total coal production capacity (China’s energy market in 2016, BP). Moreover, the exploitation and utilization of low rank coals and other coals that are difficult to float have been an important strategy for China’s sustainable development of the coal industry (Liu et al., 2014). However, the combustion of low-quality coals leads to a serious environmental pollution. In addition, the deterioration in geological conditions of coal resources, and the increasing improvement in the mechanization for mining significantly caused the increased amount of fine coal."

Jan 1, 2018

By R. J. Batterham

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

Jan 1, 2014

This study examines the surface alteration and flotation behaviour of synthetic moncheite, PtPd(BiTe)2, in the presence of pentlandite. The telluride minerals contribute around 20% ~ 30% and up to 45% of the PGM present in the Platreef ore and are considered to be slow floating as there is evidence of these minerals reporting to the tailings. It was proposed that oxidation products from other minerals and grinding media would affect the mineral surface composition and floatability thereby causing inadvertent depression of moncheite due to precipitating ions. ToF-SIMS analyses (time of flight secondary ion mass spectrometry) was used to characterise the mineral surface as well as the extent of surface alteration. Microflotation was used to deter-mine the hydrophobicity of the synthetic minerals. Conditioning of moncheite in the presence of pentlandite reduced the flotation response of the + 38 -106µm size fraction from > 99% to 56%. This was due to pentlandite dissolution products (iron and nickel hydroxy species) which formed overlayers on the mineral surfaces thereby inhibiting the adsorption of collector. In addition, further grinding of these samples, with and without pentlandite conditioning showed a negative effect on recovery due to the fineness of the particle size distribution and there was no advantage gained from any possible exposure of fresh sites in the sample.

Jan 1, 2014

By Carlos G. Rudolp, Julio C. Videla, Mario Zuleta

"The present paper summarises the results of gravity pneumatic concentration of a borax ore with 17.5 % B2O3. The sample was extracted from the Tincalayu ore deposit located in the Salta Province of Argentina.The applied methodology was based on a former study (Zuleta, 1985). It consisted of sample characterization by means of physical and mineralogical determinations, chemical analyses as well as pneumatic table concentration tests. In this, a simplified concentrating flowsheet was utilized.A concentrate with 30.6 % B2O3 and 74.7 % recovery was obtained. The recovery was 8.8 % less than previously reported and that was of 30.6 % B2O3 with 87 % recovery. Nevertheless, the simplified flow sheet presented processes only two granulometric fractions, - 6.4 mm + 0.3 mm and - 0.3 mm, compared to the three granulometric fractions used in the previous study: - 6.4 mm + 1.4 mm; - 1.4 mm + 0.3 mm and . 0.3 mm. This would simplify industrial implementation."

Jan 1, 2003

By O. D. Khmelnitskaya

The research on selecting of an efficient technology of pyrite cinders complex treatment, sulfuric acid production wastes, have been made. The grades in the initial product were 2.04 g Au/t, 35.0 g Ag /t, 0.38%Cu, 1.1% Zn. Laboratory tests on cyanide technology, thiourea and sulphite leaching were carried out. Magnetic and flotation beneficiation and biohydrometallurgical technology were tested. After considering the results of the tests, the most economically efficient technology of pyrite cinders complex treatment with cyanide leaching of precious metals was determined. The technology involves water washing of soluble copper and zinc compounds, lime treatment and cyanide leaching of gold and silver, detoxification and utilization of mineral wastes. The precious metals are recovered from solutions by cementation onto zinc. Copper is recovered from rinse waters by SW/EW and then zinc is precipitated as hydroxide. All the solutions and organic agent are used in recirculation and therefore the technology is practically waste-free. Mineral wastes can be used as iron-containing materials for cement industry. The technology has been tested in pilot-plant scale under continuous operation with complete re-circulation of cyanide solutions. In this process recovery of 54% Au, 45% Ag, 30% Cu and 50% Zn has been achieved.

Jan 1, 2014

By L. S. Gertsch

The production of minerals for human use at locations other than the Earth is expected to ?advance ? human prosperity in ? ways that [do] not compromise the potential prosperity and quality of life of future generations? (Brundtland, 1987); in other words, sustainably. This paper examines the interaction of extra-terrestrial mineral production (ETMP) with the following sustainability imperatives: ? The sustainability of human activities on Earth; ? The sustainability of human activities elsewhere; ? Human survival in general, the ultimate sustainability goal. Some of the consequences of mineral production on Earth are widely considered to decrease the future prosperity and quality of human life. Examples include noxious by-products or wastes and unsettling economic up- and downswings. Moving mineral production activities to extra-terrestrial locations, where appropriate, will decrease many of its deleterious effects. Terrestrial mineral production presently is decreasing in some countries and increasing in others, moving from the cheaper and easier ores to more expensive, difficult materials. When the full costs of maintaining the terrestrial environment in a sustainable manner are included, total mineral pro-duction costs must increase. The cost of extracting mineral products from extra-terrestrial sources will be substantially higher, especially in the initial phases, but as the full costs of terrestrial production increase, at some point in the future (different points for different minerals), the curves will cross (Fig.1). This will occur at different points for different materials, a process whose prediction will be complicated by substitution of cheaper materials for some uses as prices of the original material rise. In summary, mineral products from extra-terrestrial sources will tend to increase the sustainability of human civilization, once steady state has been reached.

Jan 1, 2014

By G. Y. Zhou

During Zijinshan copper heap bioleaching, pyrite was leached in plenty resulting in high ferric concentration in solution. It has affected bioleaching and extraction processing greatly. It results much acid and iron in solution and bad effect to extraction processing. The paper studied the influence factors in the course of pyrite leaching and ferric ion chemical oxidation, especially studied the redox potential for copper bioleaching so as to find key factors affecting the dissolution difference between chalcocite and pyrite. The results show that the redox potential is important factor. Copper and pyrite leaching rates are 95% and 11% respectively and there is great dissolution difference between them at redox potential 700 mV (SHE). During pyrite bioleaching, the indirect action of bacteria gives priority to bioleaching cooperating with the direct attack of microbial cells attached to the mineral surface. Redox potential is determined by ratio of ferric and ferrous, ferric in solution was supplied by the way of oxidation of T. f bacteria, sufficient bacteria concentration and active character were two vial factors of controlling redox potential. It is indicated that copper can be selectively bioleached during copper bioleaching by controlling redox potential of bioleaching. The conclusion will provide theoretic foundation on balance of acid and iron during bioleaching for copper of higher S/Cu ratio. The experinment proved that bacteria activation was decreased on condition of both low pH value and intermittent aeratation during bioleaching. It resulted that the oxidation velocity of ferrous ion was decreased and redox potential was controlled. The dissolution of pyrite was depressed. It would be possible to actualize selective leaching of secondary sulfide copper ore during bioleaching process.

Jan 1, 2014

By T. M. Bhatti

The main purpose of present study was to characterize the dissolution of uranium from low-grade black shale with indigenous isolated strain of Acidithiobacillus ferrooxidans (BSAF-01). The nature of shale is quartzite-schistose and contains uranium content of 0.005% U3O8 (50 ppm U3O8). Uranium is present in the tetravalent oxidation state (U4+) in the shale matrix. The main minerals identified are graphite, quartz, pyrite, mica minerals (phlogopite, biotite, sericite, and chlorite), microcline, K-feldspar and kerogen (hydrocarbon-compounds). Bacterial oxidation of pyrite was an acid-generating system and produced sulfuric acid and ferric sulfate during this biological phenomenon. A series of bioleaching experiments were conducted in shake flasks for leaching of uranium from black shale. The leaching experiments were performed at 50% pulp density using indigenous Fe- and S-oxidizing bacterium (Acidithiobacillus ferrooxidans). Bioleaching data revealed that about 90% ~ 95% U3O8 was leached out from black shale ore. Uranium dissolution from shale depends on pH (pH 1.5~1.9), redox potential (=500 mev) and the concentration of Fe2+ and Fe3+ ions in the leaching environment. The oxidative leaching of U4+ involves a redox reaction with Fe3+ as an oxidant and bacterial re-oxidation of Fe2+ in acidic leaching environment. Uranium leaching efficiency was attributed to the sulfuric acid and ferric sulfate production during bacterial oxidation of pyrite.

Jan 1, 2014

By Walter W. Focke, Zola Kwela, Willem van der Merwe, Arao Manhique

"The advantages of the de Wet zirconium process for the manufacture of AZST from zircon sand include: Fewer processing steps; removal of radioactivity by leaching rather than by precipitation; alkali reagent recovery in the form of a sodium silicate solution that is essentially free of radioactivity; fewer waste streams and less waste to discard.Here we report on our efforts at maximizing the alkali recovery in the sodium silicate product stream: Milled zircon, d50 ˜ 9 µm, was fused with caustic soda pearls in open reaction vessels at temperatures between 650°C and 850°C. Fusion times of 1, 2, 4, 24 and 336 hours (with intermittent milling) were investigated.For prolonged fusion times the fusion products approached equilibrium compositions. However, the phases Na2ZrSiO5 and Na4Zr2Si3O12 observed at 850°C did not form at 650°C. Since they do not hydrolyse in water they limit the recovery of alkali. For 2-hour fusions a broad spectrum of non-equilibrium reaction-products, that are rich in sodium silicates, is formed. Optimum process conditions, with respect to NaOH recovery, correspond to a 2:1 stoichiometry and fusing for 2-hour at 850°C. At these conditions the alkali recovery is ca. 78% and the zirconia yield is ca. 57%."

Jan 1, 2003

By Y. C. Liu

Ningxiang-type iron deposit is a most important sedimentary oolitic hematite deposit in China. Its? detected ore reserves are 3.72 billion tons, which is 73.5% of all detected reserves, and there are about 10 billion tons of prognostic resources. It is considered as the ?poor mine? for a long time be-cause of its difficult prooerty. But based on the ore characteristics of different deposits, the technological characteristics of ore are different with great diversity in ore baring horizon, distribution range, deposit scale, ore petrology, ore mineral assemblage and iron content. Through the study of deposit features and technological mineralogy of different Ningxiang-type of iron deposits in China, and based on industrial types and natural types of ore deposits, we divide different technological types according the technological features of the ore such as mineral composition, particle size, dissemination, occurrence of useful elements and harmful elements, the main physical and chemical properties of mineral and geological conditions of deposits, etc, moreover, propose the different utilization, mineral processing technologies and product schemes for the different types of ore.

Jan 1, 2014