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By Dee Bradshaw

"Process mineralogy’ is a form of applied mineralogy which focuses on addressing problems associated with the processing of ores. ‘Mineralogy’ is the scientific study of minerals and ‘mineral processing’ is the production of concentrates from ores. ‘Process mineralogy,’ however can be defined as the practical study of minerals associated with the processing of ores, concentrates and smelter products for the development and optimisation of metallurgical flowsheets, including the waste and environmental management considerations. This hybrid discipline consists of teams that include geologists, mineralogists, samplers, mineral processors and often others, working together. The degree of cross-training, communication and trust dictates the potential capacity of the team and where an appropriate work dynamic is fostered, in which relationships flourish as much as does the ethic of technical excellence, it is possible to develop technical capabilities that surpass those of conventional teams. The world’s demand for metals is ever increasing and ore deposits available for extraction and processing are lower grade and more complex, often containing deleterious elements that require tailored treatment. Generally, in the past, the technical challenges only needed to be overcome and assessed economically to make an ore deposit viable; increasingly and in the future, a more sustainable approach including environmental and societal considerations is needed. Process mineralogical assessment is increasingly providing the critical information that stands between failure or collapse and survival or success of some mining operations. In this paper, selected case studies are used to demonstrate the valuable role of the process mineralogy tools being used to provide the platform for innovative technology development. Their common attributes are discussed and distilled, thus providing some insights and potential guidance for addressing some of the likely future challenges of the mining industry."

Jan 1, 2014

By Olga D. Khmelnitskaya

The paper presents the results of research on the development of gold recovery technology from oxidized gold-copper ore of one of deposits in Russian Federation. Gold and copper grades in the ore are 9.5 g/t and 0.4%, respectively. Various options of flowsheets, such as direct cyanidation, thiourea leaching, flotation and gravity concentration followed by subsequent cyanidation of con-centration products, were tested. It was established that gravity-cyanidation technology with filtra-tion leaching tails and the use of solutions in the recirculation is the optimal option for ore treatment. The proposed flowsheet provides gold recovery for 91.0% at NaCN consumption 2.5 kg/t ac-cording to the results of pilot testing. Ammonia-cyanide gold leaching was also examined. In comparison with cyanidation, gold leaching solution in system NaCN-NH4OH-(NH4)2CO3 allows NaCN consumption to be reduced three times from 4.5 kg to 1.5 kg per 1 ton of the ore and provides the same gold recovery. Based on the laboratory and pilot plant tests results of gravity-cyanidation technology of gold dissolution, process design criteria were developed.

Jan 1, 2014

By Yuki Tsunazawa, Shuji Owada, Kazuki Tahara, Shinobu Ogino, Chiharu Tokoro

"Printed circuit boards (PCBs) are an important constituent of waste electric and electronic equipment (WEEE), and contain many electronic components with valuable, hazardous or both materials. Recycling of PCBs is an important subject not only from the treatment of waste but also from the recovery of valuable materials. Demand for rare earth metals is expected to accelerate because of their growing use in next generation high technologies. Since some of these metals are concentrated in a specific electronic component, for example, Ta in capacitors, a special and selective grinding such as parts detachment from the board is effective for the recycling of a part of rare metals. However, direct computer simulation method to investigate a comminution/detachment process of PCBs has not yet been established. In this study, our objective was revealing the mechanism of breakage phenomena in comminution / detachment process of PCBs using computer simulation. A special and selective grinding using an agitation mill promoted the removal of components from a PCB by detachment and was an effective method for the recovery of rare metals. Simulant PCBs on which some capacitors were solder-mounted were used for the comminution test using drum type mill with agitator. To describe this mechanism of the parts detachment process, a computer simulation using discrete element method (DEM) was conducted. Although only an indirect simulation using the spherical particle model was possible for part detachment and board breakage, the particle-based rigid body model could directly represent the behaviour of PCBs. Simulation results successfully corresponded to comminution experimental results."

Jan 1, 2014

By S. A. Vorobyev, Yu. L. Mikhlin, Ye. V. Tomashevich, A. A. Karacharov, M. N. Likhatski1, A. S. Romanchenko, S. V. Saikova

"A set of state-of-the-art methods have been applied to study ultrafine particles and nanoscale species arising on mineral surfaces upon milling, interaction with flotation reagents, and leaching of base metal sulfide ores in order to gain insights into interfacial mechanisms. The fine fractions produced by ball milling of a Pb-Zn Gorevsky ore and four Cu-Ni sulfide ores studied with laser diffraction, dynamic light scattering, zeta-potential measurement, Xray photoelectron spectroscopy (XPS), SEM, TEM and other techniques. The particle size distributions had, aside from the peaks at 20-60 ?m, maxima near 1-2 ?m; the flotation was considerably suppressed when the yield of positively charged ultrafine particles approached tenths % (several kg per ton). High-energy XPS and X-ray absorption spectra revealed that sulfide minerals depleted in metal in air and aqueous solutions were composed of outer “polysulfide” layers, strata with disulfide species, and heavily defective underlayers, and “passivation” was explained by stability of the metal-deficit structures. Dixanthogen at pyrite and copper-activated sphalerite, dixanthogen and then cuprous xanthate on chalcopyrite, and chemisorbed xanthate at galena were specified as the main interfacial products using cryo-XPS of fast-frozen flotation slurries. The particle size, zeta-potential and behavior of colloids of Cu and Pb xanthates and dixanthogens were largely determined by the initial ratio of a cation and collector; the properties of copper xanthate nanoparticles were also affected by incorporated dixanthogen (about 15 wt.%). Submicrometer gas domains of 3-8 nm in height and “hydrophobic” forces upon the probe retraction were found on xanthate-treated minerals using atomic force microscopy and spectroscopy; their impact on flotation is briefly discussed.INTRODUCTIONInterfacial phenomena play a key role in flotation, leaching, water purification and related environmental processes. The mineral processing and extraction of metal from sulfide ores commonly involves milling the ore, which produces, along with the particles of 20 µm to 100 µm, mineral entities ranging from micrometer to submicrometer and nanometer scale. Furthermore, ultrafine particles of flotation reagents, products of metal sulfide oxidation, and so on may form spontaneously and accumulate in production water, flotation froth, deposit on mineral surfaces, affecting the flotation performance, and then enter waste waters, mine and natural drainage, polluting soils, surface- and ground waters (Miettinen et al., 2010; Wang et al., 2014). The efficiency of flotation and hydrometallurgical recovery of values, environmental issues are crucially dependent on the state of mineral surfaces. Particularly, it is generally accepted that the surface non-stoichiometry of sulfide minerals induced by oxidation and leaching should affect their hydrophobicity and reactivity, including so-called “passivation”, but the nature of such surface layers are still a matter of controversy (see, for example, Holmes and Crundwell, 2013). Another phenomenon attracting rapidly growing interest in several areas is low-dimensional gas species (“nanobubbles”) at hydrophobic surfaces that may play a decisive role in particle-bubble attachment in flotation but remains scarcely investigated up to now (Xing et al., 2017). Here, we survey our recent results on the abovementioned problems applying a series of rather new methods and approaches; more details can be found in refs. Karacharov et al., 2016; Mikhlin et al., 2015; 2016; 2016a; 2016b; 2016c; 2016d; 2017; 2017a; Vorobyev et al., 2017."

Jan 1, 2018

By Saveliy F. Kaplan, Valeriy N. Tsyplakov, Vasily N. Kovalev, Igor A. Agapov, Nikolai V. Vorob’ev-Desyatovskii

"Based on the experiments, a possibility of successful processing of double-refractory gold sulphide concentrates with a high content of natural organic carbon, which has a high sorption capacity toward gold chloride complexes, has been demonstrated. The proposed approach involves deep burnout of sorption-active organic carbon in an autoclave at a higher temperature and a longer retention time. INTRODUCTION It is known that one of the reasons why gold-bearing ores and concentrates are refractory is the occurrence of fine gold in sulphides (usually in pyrite and arsenopyrite) in ores and concentrates. In addition, refractory gold-bearing ores and concentrates also contain an organic carbonaceous material, which has a sorption capacity towards gold chloride complex, making the ore or concentrate even more refractory. In pressure oxidation, metallic gold is oxidized by Fe (III) aqua-ions and complex Au(Cl)4- ions are formed at temperatures over 180°C, in the presence of chlorides contained in ores. Complex gold anion is adsorbed on the organic carbon surface and then reduced to Au0; the chloride ion is regenerated and gold, adsorbed on organic carbon microparticles, is ultimately transferred to tailings (preg-robbing). Currently, there are several suggestions how to suppress preg-robbing (Simmons, 1998, Pyke, 1999, Rees, van Deventer, 2000, Zhao Jun-wei, 2008). It can be done by reducing the organic carbon content by processing (flotation, etc.),reducing chloride ion concentration by preliminary washing of concentrates in thickeners, reducing the adsorption capacity of organic carbonaceous material by introducing some organic substances that are strongly adsorbed on its surface (blanking agents), and reducing the redox potential of the slurry liquids by introducing neutralizing agents (limestone)."

Jan 1, 2018

Calcium carbonate has three polymorphs: calcite, aragonite, and vaterite. Needlelike aragonite CaCO3 with a high ratio of length to diameter (aspect ratio) is widely used in plastics, rubber and ceramics as a filler and in pigments and paints as a carrier. This paper investigated the influence of H3PO4 dosage, reaction temperature, CO2 flow rate, and initial Ca(OH)2 concentration on formation of needlelike aragonite CaCO3. It was found that the presence of H3PO4 in Ca(OH)2 suspension resulted in rapid formation of (Ca5(PO4)3(OH)) crystal nuclei, which facilitated nucleation and growth of aragonite CaCO3 on the formed (Ca5(PO4)3(OH)) crystal surfaces. The results revealed that H3PO4 addition of P/Ca of 0. 2~0. 3, high temperature of 75~85 °C, low CO2 flow rate and initial Ca(OH)2 solid concentration of 1. 5 %~5. 6 % are beneficial to formation of aragonite. Well crystallized needlelike aragonite CaCO3 whiskers with length > 20 µm and aspect ratio > 15 were directly synthesized.

Jan 1, 2014

By R. Batterham

"The history of mineral processing is indeed long and has always been tied to mining methods of the day. While many new processes and devices have been developed, the most significant trend in recent times has been the ever increasing scale of operations. There is serious doubt this ongoing trend is enough to match the global trend of falling grades and rising energy demands needed for mineral processing. As well we see that globally, the social licence to operate for mining (and hence mineral processing) is far from secure. Indeed, some argue that mining as we know it is dying and in the future, mining will be much more environmentally secure, even to the extent of insisting upon “in place” recovery and only bringing to the surface the valued product. In this paper we comment on the ramifications of broader uptake of more sustainable mining for mineral processing methods and address the specific question of whether recent progress in in place recovery will lead to a timely breakthrough. The answer proposed is that this is possible in the next 10 - 20 years but in the meantime, the focus is just as likely to be on removal of waste much earlier in circuits. Either way, mineral processing as we know it will change significantly. INTRODUCTION Mineral processing has a long history well covered in a recent publication (Habashi, 2006) who points out “the ancient Egyptians knew already that it would be easier to melt an earth rich in gold particles than another which is poor. As a result, all efforts were made to enrich the gold by washing away the light gangue minerals. Similarly, another ancient method for enriching gold particles from a river stream was by means of fleece, hence the Greek myth of the “golden fleece”. Since the middle ages, striving for improved economics has driven a string of innovative developments in milling and separation. The reader is again referred to the informative and illustrative text by Habashi."

Jan 1, 2018

By A. Lewis

"Thiol collectors including the xanthates and dithiophosphates have dominated the sulfide mineral processing industry for over a century. Tecflote represents completely different chemistry, without sulfur or phosphorus, and will float all sulfides and associated precious metals. As these collectors are surfactant in nature, they comprise a head group which binds to mineral surfaces, a spacer and a long hydrophobic tail. The modification of the spacer behind the head group allows for collector optimisation for different sulfide ore types and process conditions.The Tecflote surfactants have been designed to be either very selective against pyrite at the natural pH of the ore (pH 7-9) or to float all sulfides including pyrite. Depending on the ore type and the process flow sheet, the use of lime can be maintained, reduced or completely eliminated.Tecflote can be used either as a rougher collector giving good recovery and grade for the sulfide minerals or it can be used to target valuable minerals after regrind and through cleaner flotation. It has repeatedly shown to be very effective at holding onto gold through the cleaner steps. The low solubility has a significant impact on the mechanism and surface activity of the collector, resulting in a very different flotation response compared to conventional thiol collectors.INTRODUCTIONXanthate was first made in 1882 by Zeise and first used in flotation in 1924 (Keller, 2018). In 1946 Keller patented thionocarbamate as a collector, which was produced by Dow Chemicals (Keller, 2018). Later it was replaced by Dow product Z-200, while dialkylthionocarbamate was discovered by Harris et al. (Harris, 1954. No significant chemistry change to collectors has occurred since they were introduced in the mid-20th century and now that the feed grades have been declining over the last decades creating a need to find more selective collectors to extract difficult and complex ores and pushing the industry to look at other reagents."

Jan 1, 2018

By Douglas Fuerstenau

"Comminution not only is the major energy cost in mineral processing but it also can limit the grade of ores that can economically be processed. Rittinger first postulated that the energy for comminution is proportional to the new surface produced. Because most of the strain energy needed to initiate and propagate cracks in particles cannot be recovered, researchers reported woefully low comminution efficiencies. Recognizing this, Schoenert proposed that the baseline for assessing comminution efficiency should be the mechanical energy needed to break single particles. After extensive single-particle studies, Schoenert turned to comminuting beds of particle in piston dies. Finding particle-bed comminution to be energy efficient, he had the brilliant conception of making the process continuous, namely his invention of the choke-fed high-pressure roll mill (HPGR). Practical comminution involves masses of particles, which can lead to energy efficiencies far less than that of single-particle breakage. A three-way classification of grinding modes in terms of the mobility of the particle mass provides the necessary insight into the low efficiency of different comminution machines: namely, single-particle breakage, confined particle-bed grinding (HPGR), and loose-bed grinding (ball mill). Examples are given for determining and comparing comminution efficiencies. The size distribution of comminuted products become self-similar, and a single parameter, the median size, can be used to quantify the extent of comminution. The reduction ratio, expressed in terms of the mean size of the feed and product, varies linearly with expended energy and the slope of such plots is a measure of the grindability of the mineral. This approach clearly gives the order of energy efficiency as single-particle > particle-bed > loose-bed comminution. HPGRs are more efficient at low reduction ratios but lose that advantage at higher reduction ratios. Extensive hybrid grinding experiments carried out with our instrumented ball mill and HPGR showed significant energy savings by first comminuting the material in the HPGR and followed by the ball mill. At Cerro Verde an industrial-scale hybrid HPGR/ball mill system is reported to have a 13 percent energy savings over a SAG mill/ball mill system."

Jan 1, 2014

By Markus A. Reuter, Jacques J. Eksteen

"The modelling of bath type furnaces tends to be either fundamental in nature or total empirical ""black box models"". While models of the first kind are robust, they tend to lack accuracy, in cases where they are to be used for process control, and may take an overly long in development time. On the other hand, black box models tend to lack robustness of prediction for all circumstances and tend to be limited to interpolate based on historical data. While this may very often provide short-term accuracy, the models may have problems with stability in the long term. Moreover, the model structure may not reflect any of the fundamental properties of the system and remains opaque to fundamental analysis. The aim of the model development is in obtaining a model that have robustness, high accuracy, a short development time and which is adaptive to a changing environment. The models are specifically developed for on-line decision support or control of furnaces. The modelling approach is evaluated for a chromite bath smelting furnace. The role of systems analysis, mass balance smoothing, thermodynamic analysis are integrated into one generic algorithm for bath type furnaces. Not only are fundamental process relationships such the mass and energy balances satisfied through a scientific method of data reconciliation; the proposed modelling approach allows adaptive prediction, the first step towards predictive control or metallurgical decision support.It is shown that neither an ARMAX model only, nor a purely equilibrium model only, could predict the dynamics of the process very well. However, a combination of the two approaches more than doubled the accuracy as measured by the R2. It was noted for carbon dissolved in the alloy, that the improvement in R2 in using a hybrid modelling approach was more than the sum of the R2 of the individual traditional approaches. Similar improvements in modelling performance were noted for all other species.It shows further that process dynamics may totally overshadow the effect of thermochemical equilibrium (even when the thermochemical equilibrium prediction includes the recycled alloy and slag heels as additional feeds). The exclusion of process dynamics therefore leads to erroneous results."

Jan 1, 2003

By S. Swaroopa

Copper-chromium mixed oxides are widely used as catalyst for organic chemicals industry, NOx and CO oxidation, solid propellant etc. In the present investigation, one such spent Cu-Cr catalyst has been tested for recovering copper and chromium values through hydrometallurgical route. The spent catalyst used in this study contains about 42% Cu and 36% Cr. Phase analysis through XRD indicates that major phases are copper chromium oxide (CuCrO2) and copper chromate (CuCr2O4) while minor phase is copper oxide (Cu64O). SEM images show that high energy ball milling changes surface morphology significantly ? more regular shaped grains in unmilled samples changed to fine agglomerates. Surface area also changes significantly due to milling. Preliminary leaching experiments with NH3 and H2SO4 media using unmilled samples indicate that both the media are suitable for selective extraction of copper. About 55% copper recovery is achieved in 2 h using 1.2 M NH3 + 0.2M (NH4)2SO4 solution at 100°C. Increasing NH3 concentration or temperature does not improve the recovery significantly. Under the above conditions chromium, dissolution is insignificant (max. 2.24%). XRD analysis of the residue indicates that copper chromate fraction (CuCr2O4), which is a spinel structure, remains mostly intact. In sulphuric acid media at ambient temperature, 47% copper recovery is achieved with 7.5% (v/v) H2SO4 and maximum of 57% with the increase in acid concentration to 20%. However, 67% recovery is achieved by increasing the leaching temperature to 150°C. High energy ball milled samples show improved leaching efficiency. Under the leaching conditions of 7% H2SO4 (v/v), 2% pulp density, 80°C an unmilled sample yields 47% Cu recovery whereas 3h and 5h milled samples yield 65% and 90% Cu recovery respectively in 2h leaching time. Influence of temperature is also more pronounced in milled sample leaching in comparison to unmilled sample. Water leaching of alkali (NaOH) roasted milled sample carried out at 750°C for 2 h with 100% NaOH (w/w) resulted in 80% Cr recovery as compared to 37% Cr recovery using unmilled sample under the same conditions. Keywords: spent catalyst, copper, chromium, leaching, mechanical activation, roasting

Sep 1, 2012

By T. Onnela

Metso Mining and Construction Technology is one of the world leading suppliers of equipment and knowhow for aggregate and mining industry. The processing capacity, ease of use, and reliability are featuring Metso?s state-of-the-art cone crushers. Crushing is a complicated process affected by numerous parameters. The optimized crusher kinematics is one of the key factors for high performance. To fine tune the crusher kinematics and crushing chambers one needs to know how different parameters affect. The main cone crusher parameters are head angle and diameter, gyration point, shaft speed, eccentricity, stroke length, and inclination and design of crushing cavity. Selecting the correct combination of these parameters is a multi task optimization challenge. In practical life there are more factors to achieve satisfactory performance, like crushing chamber wear and profile management keeping the performance constant over the whole wear life, control of crusher frame loads, ability to handle disturbances in feed material etc. The extensive research work has lead to a solution that enables the highest possible material density in the crushing chamber. This design provides maximum reduction of processed material and thus increased share of 0/10 mm product. High density in the cavity offers further benefits, such as high throughput capacity, less material contact with wear parts and even load on crusher frame and bearings. The challenge that an equipment supplier involved with high density crushing is how to design a robust cone crusher, which is able to cope with the high crushing forces due to high resistance from the crushed material against the gyration movement. Metso has launched a new series of cone crushers HP3, HP4 and HP5 that are all able to work in high density crushing applications The test results and evidence from over 300 installations clearly prove the effectiveness and importance of high density crushing. Keywords: cone crusher, crushing chamber, crusher kinematics

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 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 K. Saberyan

In this study, solvent extraction of zirconium by using triphenylphosphine oxide as extractant has been investigated. The results showed that extraction of zirconium by triphenylphosphine oxides in nitric acid and hydrochloric acid media were negligible. Extraction of zirconium in acetic acid media with concentration of 0.01~0.2 M has been studied and the results showed that the maximum percent of zirconium extraction was 40% in acid acetic with concentration of 0.01 M. By addition complexing agents such as potassium thiocyanate with the concentration of 0.01~0.2 M zirconium extraction increased up to 86% in 0.2 M potassium thiocyanate. By addition of sodium salicylate with concentration of 0.01 M and in pH=2.5, the maximum extraction of 96% was achieved. The striping of zirconium from organic phase can be carried out by 0.5 M solution of sulfuric acid.

Jan 1, 2014

By Minna Päällysaho

For the first time, the idea of sustainable development was recognised at a high political level at the UN Conference on Environment and Development held in Rio de Janeiro in 1992 (UNEP, 1992). Then the governments of the world committed themselves to promote sustainable development in their national activities and international co-operation. In 2001, the European Council approved the EU Strategy for Sustainable Development (European commission, 2011). This complements and supports the EU?s so-called Lisbon Strategy (European council, 2000) on competitiveness. The revised Strategy for Sustainable Development was approved in June 2006. Recently sustainability has had an important role in policy and decision-making while the public awareness towards limits of the environment has been rising. However, the indicators of industrial sustainability satisfy primarily the needs of corporate management and global investors. The information is often broad and non-specific and might occasionally even give a false impression. Moreover, contradictions between environmental, economical and social aspects also point out the unreliability of existing sustainability indexes. Therefore, the current state of affairs serves the interests of neither the industry nor the policy makers. Current corporate sustainability indexes and indicator systems need to be assessed with scientific methods encompassing the identification of their strengths and weaknesses. This requires quantitative and qualitative assessment and synthesis of existing indexes and indicator systems, providing new data on the functionality of existing corporate sustainability indicators. Therefore, the assessment lays the foundation for the development of new, more balanced sustainability index. Our first aim in this multidisciplinary article is to analyse existing global sustainability indexes for process industry. Second, we will introduce a first version of a new sustainability index for process industry, which includes the environmental, social and economic impacts of the plant, as well as legislation aspects.

Sep 1, 2012

By Robin J. Batterham

Alumina demand is steadily climbing around the world and is likely to continue to do so for many years. In such a commodity industry, the question arises as to what effort should be expended on innovation, given that for an individual company, the drivers of change are cost and quality as the market demand is essentially assured. This is of course a long-term view. The current conditions are less attractive. In this presentation, we review the broad issues that are considered targets for collaborative development by the industry as recently updated in the alumina industry roadmap published by the International Aluminium Institute in 2010. While they cover areas such as ?mine rehabilitation, residue management and use, alumina production from high sulfur bauxite, bauxite beneficiation, energy efficiency and alternative technologies for alkali and alumina recovery from bauxite residues,? it must be remembered that each refinery is different in terms of the feed material and the circumstances of waste disposal. Of particular interest is the more competitive area of breakthrough technologies. In the presentation, we will consider a range of opportunities that could transform the industry, from relatively near term possibilities such as bauxite activation through possibilities to eliminate crystallization as currently practiced to complete alternatives, such as the use of hyperaccumulating plants. Against this optimism, some of the realities that hold back breakthrough innovation will be presented for discussion.

Sep 1, 2012

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 T. Laxmi

This paper details the optimization of rougher Wet High Intensity Magnetic Separator (WHIMS) using response surface methodology. The optimization is in parametric form and takes account of the major operating variables in WHIMS operation such as current in ampere and grid gap, in inch. The objective is to recover ilmenite mineral from red sediment deposits of Srikakulam, India by optimizing the rougher WHIMS. We predict mineral recoveries as a function of current and grid gap. Combination of these predictions with assay data provides predictions of mineral grades and recoveries. The optimized response was validated against data derived from laboratory-scale rougher WHIMS test work, comprising (i) mineral grade, (ii) mineral recovery, and (iii) separation efficiency of the process. We observed close match between the experimental and the predicted data over most of the operational range. This paper describes how the optimization was carried out using the response surface methodology along with MATLAB. The response surface was used to closely investigate the separation of ilmenite mineral by varying ampere and grid gap. The results show that under optimum conditions, such as 3.5 amp current (0.53 Tesla) and 2 inch grid gap, the mineral grade could reach, as high as 87.9% in the concentrate with 74.3 % recovery and 74.4% yield. Keywords: red sediment, wet high intensity magnetic separator, optimization, ilmenite, placer heavy minerals

Sep 1, 2012

By Venkataramana Runkana, Pradip Gautham, Beena Rai, Sreedhar Reddy

"IT enabled platforms are the key to provide an integrated view of the business activity or an enterprise as a whole. Attempts to integrate all functions in an enterprise such as mine-to-market initiatives, wherever and to whatever extent implemented, have provided significant benefits to the industry. The transformative potential of IT enabled integration platforms is illustrated in this communication from our own work in this field. TCS PREMAP (Platform for the Realization of Materials and Products) is a knowledge-driven engineering design and development platform which leverages modeling and simulation and artificial intelligence into the engineering design process. We illustrate the customization of this generic platform for the design and optimization of mineral processing plants in an integrated manner. TCS PEACOCK (Process and Equipment Analytics for Optimization and Control) has been developed to enable automation of data analytics in the operating plants. We illustrate its utility and power in improving the plant performance with the help of case studies from our work on pelletization of iron ores and optimization of flotation plants. INTRODUCTION We are living in an exciting digital era. With the advent of cloud computing and social media on the one hand and rapid advances being made in several research areas of interest to us in the minerals and metals industry such as artificial intelligence (AI) & machine learning, robotics, unmanned vehicles including drones, big data analytics, 3D printing, sensor technologies, renewable energies and internet of things (IoT), many disruptive transformations in our industry are on the horizon. Recent advances in information technology (IT) and knowledge engineering, in combination with appropriate domain expertise, that is, our enhanced understanding of the underlying science of mining and mineral processing operations and the availability of a variety of powerful modeling-simulation tools make it possible to address the challenging problems facing the mining and mineral processing industry, in an integrated manner."

Jan 1, 2018