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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 Paul Gottlieb

This paper reviews the status of automated applied mineralogy today and describes the history and fundamental theoretical and practical bases underpinning the development of automated systems. Details are given of the technical challenges that were faced in creating the new technology and in applying it to a range of applications. In recent years, automated mineralogy has become established as an essential enabling technology for the reliable acquisition of statistically sound comprehensive mineralogical and metallurgical data. This has had a revolutionary effect on the industrial use of such data in the study of geology, mining and mineral processing. Previously, using manual methods, it was not feasible to attempt this work because the large data sets required could not be assembled in a realistic timescale. There was a reliance on individual expert mineralogists and this was not scalable. The speed, reliability, detail and repeatability of the modern automated measurements has now made this type of analysis routine. Automated Applied Mineralogy has come of age! More than 100 systems have been installed around the World. Automated mineralogical analysers such as QEMSCAN® were originally developed as diagnostic metallurgical tools to improve mineral processing plants using samples drawn from plant surveys, bench and pilot-scale tests. They were used mainly for the assessment and auditing of size fractions of mill products, such as concentrates and tails. Subsequently, they began to be used for concentrator design and optimisation where ore characterisation was used to help understand the relationship between the feed ore and its subsequent behaviour in the plant. They are now widely used to measure exploration cores and drill chips from drilling programs to predict eventual metallurgical performance. Ore samples can be classified into metallurgical, as well as geological types, by combining mineralogical features in the ores with metallurgical properties related to grade control, separation, comminution, flotation and leaching behaviour. Three-dimensional block models of ore deposits are now being created based on processing response in addition to geological and mining properties. The development of automated systems began in Australia, the United Kingdom and Canada in the late 1970s and early 1980s. There were many technical challenges. Mathematical theories of randomness, sampling theory, image analysis and stereology were developed to ensure sample representivity so that meaningful information could be obtained. Sample preparation, presentation and measurement methods were developed to ensure that the random sampling was preserved during the measurements. Methods of automatic measurement and mineral identification evolved from the use of electron microscopes, fitted with backscattered electron brightness and energy dispersive X-ray detectors. Operational procedures were required to ensure that these instruments could accommodate a large number of samples and operate unattended for long periods of time. The new technology was progressively applied to a range of commodities and applications and new analysis methods, such as liberation measurement, were needed for metallurgical interpretation of mineralogical data.

Jan 1, 2014

By Vladko Panayotov, Marinela Panayotova

"Recently, in order to extract metals, the industry is trying to process old metallurgical slag. The material requires very fine grinding that results in enhanced slime-formation. This in turn leads to problems in the course of the flotation process and to a loss of metal. In addition, it causes difficulties in the wastewater treatment aimed at water reuse. The aggregation and separation of the fine particles and their further subjecting to mineral processing would result in more efficient use of raw materials. Closing the water cycle also would be facilitated. The paper presents results from studying sixteen flocculation reagents, commercially available for treating municipal wastewater, including products based on nanotechnology, for their ability to rend the production wastewater in suitable for reuse in the flotation. It turned out that, from all studied reagents, the cationic C-587 is suitable for the purpose. Some of reagents were studied for their ability to flocculate selectively, in presence of coke fines, rich in copper fines which are produced at grinding of a slag from lead-zinc metallurgy. Most promising reagents are chosen, based on the chemical analysis of the flocculated materials. Open-cycle rough copper flotation experiments with the flocculated fines and recycled wastewater gave encouraging results."

Jan 1, 2014

By Peter N. Holtham, Geoffrey J. Lyman, Matthew S. Brennan, Vijay Subramanian, Rui X. Rong, Tim Napier-Munn

Studies of the dense medium and classifying cyclone have been conducted using the Fluent computational fluid dynamics code. Experimental measurements of the segregation of medium in a DM cyclone by gamma-ray tomography and the performance of a novel classifying cyclone design have been used to test and interpret the 3D CFD predictions. The predictions of the CFD models were generally plausible, though more work is required to incorporate turbulent mixing of the slurry in the cyclone. The benefits of the novel cyclone design were explained by the model in terms of conditions favouring reduction of short-circuiting at the vortex finder, and the removal of the air core from the wall at the apex. Work is continuing.

Jan 1, 2003

By A. D. Bas

Copper minerals present difficulties during the cyanide leaching of gold ores leading to excessively high consumption of cyanide (and oxygen) coupled with low extraction of gold. Copper cyanide species, if present at high levels, adversely affects the downstream processes such as the activated carbon adsorption and the effluent treatment. In this study, the extraction of gold from a copper-bearing gold ore by ammoniacal cyanide leaching was studied. Furthermore, ammonia leaching as a pretreatment process ahead of cyanide leaching was also examined. Only ~12% of gold was extracted by direct cyanide leaching of the ore. The addition of lead nitrate did not affect the leaching of gold. When ammoniacal cyanide leaching system was used, the extraction of gold was significantly improved to >90%. Similarly, the pretreatment of the ore by ammonia leaching was shown to lead to high gold extractions (98%), in subsequent cyanide leaching with significant reductions in the consumption of cyanide. This appeared to be linked with the ready dissolution/removal of copper during ammonia leaching.

Sep 1, 2012

By G. Aguilera

The mineral suspensions do not present a newtonian behavior as their continuous phase; they can be pseudoplastic, dilatant, or both. The viscosity becomes as the most important rheological variable because the different industrial processes involve a wide variety of rheological scenes, with a specific rheological behavior for each one. Some authors have tried to model the viscosity of suspensions considering the volumetric fraction of solids and others have also kept in mind the size of the particles (Einstein, 1906; Batchelor, 1977; Jinescu, 1974; Krieger and Dougherty, 1959; Tangsathitkulchai and Austin, 1988). Others consider the shear rate (Cross, 1965; Hershel-Bulckley, 1926; Bingham, 1916, etc). However, none of the models is able to simulate the viscosity involving the physical, chemical and mechanic factors at the same time for crowded suspensions. A new model based on Neural Networks is presented, taking into account all the variables of ceramic clay suspensions and chemical additives. Keywords: viscosity, clay minerals, neural networks, simulation, mathematical function

Sep 1, 2012

By T. S. Reddy

Research and Development Centre for Iron and Steel (RDCIS) a unit of Steel Authority of India Limited (SAIL) is continuously engaged in reduction of energy consumption at SAIL plants by implementing innovative and new concepts. In this regard, continuous efforts are being made to recover waste heat in Sinter Plants. This paper discusses existing waste heat recovery measures taken and proposed measures planned in Sinter Plants. One such effort is on waste heat recovery from sinter coolers. Hot sinter is discharged to the crusher at the end of the sinter machine at a temperature of 500 to 800°C. Temperature of hot sinter is brought down to nearly 100°C in the sinter cooler with air-cooling. The air after cooling the sinter is generally discharged to the atmosphere at about 225 to 300°C. It is planned to recover heat from the hot air that is being released to atmosphere and heat the process water, which is being added at ambient temperature in mixing drum at Bhilai Steel Plant. The temperature of raw sinter mix will be raised by addition of this hot water, which will help in improving the productivity of sinter machine. It is estimated that Waste heat recovery to the tune of 1.5 to 2.0 Gcal/h is possible with reduction in CO2 emissions in the range of 4000 to 5000 ton/year. The novel approach that is being adopted is addition of hot water in mixing drum for higher sinter productivity for the first time in India. Keywords: waste heat recovery, sinter plant, hot water generation, emission reduction, CDM

Sep 1, 2012

By Zehong Wang

Selecting sodium polyacrylate (PAAS) as grinding aid, the effect of grinding aid on the grinding efficiency of bauxite taken from Shanxi province was studied and its mechanisms were analyzed by measuring the variation of adsorption characteristic, pulp viscosity, surface electric potential of the bauxite and the surface appearance of particles. The results showed that, compared with no grinding aids added the content of -0.074mm in the ground product was increased by 5.45 percentage points under the optimal grinding conditions adding PAAS as grinding aid when the amount of PAAS was 0.7%wt of bauxite. Because the physical adsorption and chemical adsorption were occurred on the bauxite surface, which could reduce the pulp viscosity, change the surface electric potential of the bauxite, enhance the surface appearance of particles and lower the surface hardness of the bauxite, the grinding efficiency of bauxite was increased by PAAS. Keywords: bauxite, grinding aids, grinding efficiency, mechanism

Sep 1, 2012

By A. Lane

Africa is ripe with opportunity for the mining industry. The continent has large, and relatively unexplored mineral deposits, and recent high economic growth rates have meaningfully improved the political, economic, and infrastructural environments. However, these opportunities are accompanied by significant risks, including resource nationalism, uncertain regulation, corruption, and continuing political instability (up to and including war). Forward-looking companies actively manage these risks by creating a sense of shared purpose with the countries and communities that own the resources, using tools such as stakeholder analysis, local narratives, scenario planning, and constituency engagement. They also measure socio-economic impact to insure the creation and demonstration of shared value.

Sep 1, 2012

By C. L. Xiao

With reference to the test report carried out by Guangzhou Nonferrous Metal Research Institute in 1983, the mineral process flow sheet of Yichun Tantalum-niobium mine is determined based on the characters of ores and successful experiences in light of the problems in the existing flowsheet: The ore is desilted before crushing; the primary slime is separately treated; the staged grinding process used while the fine slime is collectedly treated with tantalum and niobium as the main recoveries and lepidolite and feldspar powder as the secondary. The flowsheet is featured by comprehensive recovery, low investment and low energy cost.

Jan 1, 2014

Cenospheres is a sandlike hollow sphere component of the fly ash that is collected in coal-burning electric power generating plants. Metal coated particles have been widely used in industries. Magnetron sputtering method which was used to coat copper film on the surface of the cenospheres is a widely used coating technique in large surface metal coating. A newly designed equipment is used to make the fine particle coating can be carried out because the fine particle is hard to disperse and it must make the particle keep moving to let every direction of the particle be coated. The copper film coated is compact, smooth, even and without uncoated spots under the optical microscopy and SEM. The film has good affinity to the cenosphere surface. The film does not separate with cenoshpere surface even when the cenosphere is crushed. The XRD, SEM, XPS, SPM was used to study the copper film characteristic. It is shown that using this newly designed magnetic sputtering equipment can coat high quality copper nanofilm on the cenoshpere surface.

Jan 1, 2014

By G. R. Forbes

Flotation froth machine vision systems provide consistent real-time measurements pertaining to the state of the flotation cell being monitored. Typical measurements include froth velocity, froth colour, froth texture and froth stability. This paper presents the results from test work conducted on the molybdenite rougher circuit at the Kennecott Utah Copper Concentrator during February 2006. Machine vision results show that it is not possible to accurately determine bubble size distribution information for the molybdenite froth, despite using state-of-the-art methods. Instead, it is necessary to make use of texture measurements to classify the various different froth states. Numerous combinations of texture measurements and classifiers are used to determine the best combination. Results show that the Fourier ring based texture measurements perform the best when both K nearest neighbour and Gaussian mixture model classifiers are used. The concentrate grade of the flotation cell is modelled using combinations of froth velocity and froth texture descriptors. The results show that by using a linear combination of these descriptors rather than either one by itself it is possible to account for a much larger percentage of the variation observed in the concentrate grade data. Adjusted R2 values of 92% and 84% are achieved when modelling the copper and the molybdenite concentrate grade respectively.

Jan 1, 2014

By F. Q. Cheng

As the important potash, the product yield of KCl in winter is low and the resources waste is serious according to the deficiency of collectors, which can be used in this condition currently. This paper studied on the change of contact angle, turbidity, and flotation recovery of KCl particles when different chain lengths, ratios of amines were used as collectors in KCl flotation process to get a new mixed collector. The contact angle values of KCl crystal in its brine solution added different amine collectors were first measured by captive bubble method. The turbidity of brine solutions were then measured by the laboratory turbidimeter at room temperature when different amine collectors were contained. In the end micro-flotation experiment using mixed amine with fixed ratios and ODA as collectors respectively at 5 °C, 23 °C were performed. The results show when the ratio of the mixed amine is DDA- 20%, ODA-60%, C20-20%, the contact angle at KCl surface is the maximum and the hydrophobic state is best. Meanwhile the result of turbidity measurement indicates that the dispersion of mixed amine colloids is better than the ODA collector due to the addition of DDA, which plays the role of frother. The flotation results also prove that the mixed amine is not only fit for the KCl flotation at room temperature but also fit for its flotation at low temperature. This study provides strong technical support to extend the production time of potash business in Chaerhan areas in China.

Sep 1, 2012

By Thomas Mütze, Petya Atanasova, Kai Bachmann, Urs A. Peuker, Thomas Leißner

"A method is presented for the evaluation of mineral processing by liberation and upgrading. The method bases on the plot of recovery of valuables versus the recovery of gangue (Fuerstenau upgrading curve). The locking curve of a feed material was plotted together with the upgrading curve in a Fuerstenau diagram. The assessment of liberation and upgrading is done by a comparison of surfaces formed by the curves and some characteristic lines of the diagram. This plot allows the calculation of two new quantitative measures for liberation and upgrading. Both parameters can be combined to a third parameter describing the quality of the whole technical setup for mineral processing by subtracting the upgrading parameter from the liberation parameter. The third parameter shows a positive value in cases of upgrading determined processes, a negative value in cases of liberation affected processes and about zero for processes affected equally by liberation and upgrading. Thus it is easily possible to distinguish between poor results in the mineral processing caused by insufficient liberation or poor results caused by insufficient upgrading. Preliminary results from two case studies, performed on two different ore types, are very promising illustrating the practical use of such an approach."

Jan 1, 2014

By E. Lee

With the growing environmental concern, as well as the increasing concern for sustainability of natural resources, the need of improving the performance and efficiency of today?s crushers is be-coming increasingly important. However, the development of existing crushers requires an extended basic knowledge about the crushing process itself. The aim of the present study is therefore to find the theoretically optimal way of crushing compressively under given circumstances. In the present paper, optimizations have been performed with the purposes of maximizing product yield and minimizing energy consumption. Performed on an ideal crushing stage free from physical limitations, the optimization results have been obtained in terms of number of compressions and their corresponding compression ratios. Complementing earlier results on interparticle breakage (Hulthén et al., 2006), presented here are thus the results from corresponding optimizations with single particle breakage and interparticle breakage. It is concluded that modern crushers are not working optimally in any of the studied aspects for gneiss. In fact, optimizations indicate that a lowering of the compression ratio, as well as a shortening of the crushing sequence, are theoretically favourable. The outcome of this study is therefore highly promising as to giving new ideas and suggestions of improvements in existing crushers, and can even result in redesign of compression crushers.

Jan 1, 2014

By M. Zolghadri

MIBC and sodium metasilicate are used as a frother and a dispersant in coal flotation respectively. In order to study interaction between them, flotation experiments were performed on fine coal (<150 microns). It was found that if the frother (MIBC) dosage is in excess of a certain limit, it has an activation effect on the gangue minerals associated with coal. In addition, it was found that however sodium metasilicate can disperse clay slimes eliminating slime coating, but in the case of excess dosage, could intensify activation effect of MIBC, which is undesirable in coal flotation. Keywords: coal flotation, sodium silicate, frother, dispersion, activation

Sep 1, 2012

New technology for on-line particle size analysis of mineral slurries has opened up new applications for particle size measurement. In some cases the particle size distribution of the final concentrate is an important quality issue. This paper discusses established on-line particle size analysis technologies and presents experiences on the use of a new technique employing laser diffraction in several minerals processing operations. The main innovations in the new instrument are a simple dilution system and multiple scattering correction algorithm, which allows wide solids content variations of diluted sample in the measurement cell. Representative sample for laser measurement is produced by a simple and reliable dilution system. The applications discussed are; Blaine number measurement of Fe concentrate before pelletizing, grinding of variable batches of ore and paste thickener control.

Jan 1, 2014

By Bertil I. Pålsson

The most common REE containing mineral that is worked today is bastnäsite. It means that mineral processes are adapted to it and that the metallurgical separation techniques for winning of individual REE are adapted to bastnäsite concentrates. For all other deposit types, suitable mineral processing methods and separation technologies need to be adapted and/or developed. Preliminary mineralogical analyses indicate that slightly less than half of the REE in the tailings dumps at LKAB/Kiruna are associated to apatite. The rest is in the minerals monazite (maybe associated to apatite) and allanite. At least allanite is probably not floatable with reagents commonly used for apatite. Mass and element distributions for the tailings sand reveal that very little apatite is present above 300 µm, and that approx. 30 % is below 20 µm. REE does not follow P2O5 completely and are also present in coarser fractions. Flotation results show that the best condition for both apatite and REE winning is pH 9, high collector addition and low dosage of water glass. Under these conditions, the lab-scale flotation gives an apatite concentrate with at least 30 % P2O5 at 70 % recovery. REE follows apatite in the cleaner steps but only partly. Its recovery is approx. half compared with apatite. The reason for the low REE recovery is likely to be that REE to a large extent is trapped in non-winnable minerals, especially allanite. The REE grades in the concentrate are expected to be in the range 3000 ? 4500 g/ton. Keywords: flotation, REE, apatite, monazite, allanite

Sep 1, 2012

By N. S. Phala

Declining gold grades, mineralogical complexity of ore bodies, increasing input costs, more stringent conditions in the licenses to operate, and uncertain gold price dynamics combine to exert significant ongoing pressure on margins of gold producers. Innovative approaches of extracting the metal from its ores are required to realize value from existing and future assets. In a conventional gold processing plant, size reduction of mined ore to produce floatable or leachable product is a significant cost contributor. A step change in cost reduction will be attained if radically energy efficient grinding approaches can be developed, replacing tumbling mills. In the path towards that goal, some quick wins are possible through waste rejection before grinding, and pre-treatment of mill feed to reduce grinding energy demands. Gold locked in complex mineralizations puts pressure on margins by increasing cost per oz (typically high $/t and low metal recoveries) in the hydrometallurgical steps. Gold miners are primarily price takers. The current narrow range of gold uses (predominantly investment and jewellery) is not an entirely desirable state. Some diversification into commercial uses would potentially be a price stabilizer. In this paper, promising research directions, some not always fully explored in the gold metallurgy research space, are highlighted to stimulate radical innovation for substantial value enhancements. The author strongly believes a shift from a traditionally conservative and incremental innovation approach to a more aggressive one, across all aspects of the gold metallurgy value stream (processes to products), is what the industry needs. Keywords: gold metallurgy value stream, thiobaccilus ferroxidants, HPGR

Sep 1, 2012

By Chi Zhang, Junyi Wu

"With the increasing popularity of lithium cobalt oxide in lithium ion battery industry, which is driven by new energy vehicle and mobile device applications, the demand of cobalt is also growing rapidly in recent years. There is a significant trend of increasing investment on cobalt capacity in China, and the automation renovation is considered as an option of improving production efficiency. This study aimed at evaluating the practicability of stainless permanent cathode blank and automatic stripping process in cobalt electrowinning process. The purpose is to replace the old starter sheet process in cobalt electrowinning, which so far was used by most of cobalt refineries in China, but very labor intensive and exposed operators to serious aerosols that contained both cobalt and acid. In the old starter sheet process, the initial cobalt starter sheet is produced onto a plate made of titanium, while the titanium cathode blank and hanger bar fit the critical corrosive environment but is lack of mechanical strength for automatic production which has been mature in copper electrowinning process. To evaluate the proper materials instead of titanium, the coupon corrosion tests with different raw materials including 316L and other stainless steel grades were held for several months in production environment at a cobalt tank house in China. Following the comparison between titanium and other tested materials, a pilot production test in a cobalt tank house is also on-going.INTRODUCTION Cobalt has been known in early China and used in pottery glazes, and the ancient Greeks and Romans used its compounds to make colored glass since long time ago. The blue on the colored porcelain from the Tang Dynasty in China was also due to the presence of cobalt compounds. The word cobalt is known being derived from the German kobalt, from kobold meaning ""goblin"", because the cobalt-bearing blue ore, CoAsS, was called kobaltin in Europe in the Middle Ages, it may have been thought to be harmful to the health of the miners because of arsenic in the ores."

Jan 1, 2018