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By P. K. Rozakeas

It has been experimentally demonstrated that the application of electrokinetic techniques in the continuous flow of coal-water suspensions within a helical anode-cathode pipe geometry effectively causes a significant reduction in the wall shear stress. This reduction in the frictional force at the cathodic pipe wall surface is attributed to a decrease in the concentration of coal particles in this flow region caused by the migration of negatively charged coal particles towards the anodic surface(s). The disadvantage of flow-intrusive geometries is the reduction in effective flow area as well as an increase in frictional surface area caused by the placement of the anode(s) within the flow region. Experimental data is presented for a non-intrusive helical anode-cathode geometry embedded in the pipe wall which shows that a reduction in pumping energy of approximately an order of magnitude is possible. A sample of sub-bituminous black coal fines having a mean particle size of approximately 17 microns was used to prepare coal-water suspensions with a solids concentration of 50%(w/w). The practical and economic implications of this work relate to an enhanced method of long distance transportation of slurries in pipes as well as an alternative technique for continuously separating solid-liquid suspensions.

Jan 1, 2014

By I. Gombköto

To sustain the growth of industrial production necessitates the increasing of the amount of processed mined raw and secondary materials. As a side effect of raw material production, the amount of tailings material, - coming from mineral processing operations ? increases as well. Using wet technology, these tailing materials are generally transported and stored with the water used for previous operations. This habit could lead to dangerous situations. Enough to remember the disasters had happened to the last decade, safe tailings operations need to remove as much water from the solid as possible. Environmental, technical and economical needs should meet, therefore using a technology combining these specific needs could be necessary. Paste technology was introduced generally into tailings operations at the last ten years, as an answer to the call of the above mentioned challenges, however there are still many questions to answer within the frame of using it. The Institute of Raw Materials Processing and Environmental Process Engineering of the University of Miskolc has been dealing with mechanical process engineering, especially by the support of the EU project TAILSAFE Contract nº EVG1-CT-2002-0066 and the NKFP 3A/068/2004 Hungarian fund extensive research has been carried out about paste technology. Different test methods and materials were applied. Tested tailings materials were as follows: different fly ashes from coal power plants from Pécs ? Hungary, Gyöngyös ? Hungary, Neyvil ? India, different Croatian ashes, hazardous waste incineration plant ashes from Dorog ? Hungary, different kind of sands from Hungary, fine glass sand from Fehérvárcsúrgó ? Hungary, flotation ore processing tailing from Gyöngyösoroszi ? Hungary. Different additives, as gypsum, bentonite and cement were tested as well. The applied test methods were as follows: physical material testing (laser sizer, piknometer, different microscopes), X-ray diffraction analysis, settling columns, the three measuring pipes tube viscometer (16~27 mm pipe diameter), a hydraulic test loop with different pumps (40~53 mm pipe diameter, 0.2~4 m/s average slurry velocity range, 0%~52 % volumetric concentration range), rotational viscometer, Cassagrande yield locus tester and the slump cone test. This paper summarizes and systematizes the results of the aforementioned research as well as reports about the developed paste pipe transport design method based on the fine suspension ? coarse mixture model. The paper also reports about a systematic experimental series with different materials to establish criteria when high concentration suspensions behave like paste.

Jan 1, 2014

By Gábor Mucsi, József Faitli, Imre Gombköto, Sanjay Kumar, Zoltán Molnár, Balázs Ráczkevi, Ádám Rácz

"Generally, fly ash particles are very fine (< 100 ?m), mainly spherical and glassy materials form an outer shell on it. This paper deals with the laboratory investigation of ground fly ash based geopolymer. This material can be applied in many fields, mainly in the construction industry, e.g. non-structural elements, concrete, pavements and products, containment and immobilization of toxic, hazardous and radioactive wastes, advanced structural tooling and refractory ceramics, and fire resistant composites used in buildings, etc. The preparation of fly ash using high energy density milling is presented. Systematic experimental series were carried out in order to optimize the preparation process. The particle size distribution (LPSA) and structure of fly ash (FTIR) and the uniaxial compressive strength ,the permeability and structure of geopolymer product, furthermore the rheology of geopolymer paste were investigated. The product properties were studied as a function of the fly ash fineness. As a result of the investigation the relationship between the grinding circumstances, the ground material properties and the geopolymer characteristics was identified. It was found that the above mentioned physical properties of the geopolymer strongly depend on the grinding process."

Jan 1, 2014

Separation performance of a Floatex Density Separator (FDS) has been studied both experimentally and theoretically. Experimental results reveal that at a lower bed pressure the FDS acts like a classifier. Higher bed pressure is required to attain the concentration effect as proper development of suspension density occurs under these conditions. It is seen that the size or density alone is not able to describe the partition fully. The terminal settling velocity, which includes both the size as well as the density of the particle can be a useful descriptor of separation in a FDS. While a narrowly distributed feed offers better performance of a FDS, a wide size distribution of feed results in large scatter in the terminal settling velocity distribution and renders the separation difficult. The closely sized feed enhances the density effect in concentration. A higher teeter water flow rate also helps in carrying larger-lighter particles to the overflow by increasing the cut off terminal settling velocity as it increases the net upward force. A detailed description of separation performance in a Floatex Density Separator has also been established from theoretical considerations. Separation performance of the separator is described using a simple slip velocity model. The model has been validated com-paring the predicted FDS performance results with those experimentally measured under widely different operating conditions.

Jan 1, 2014

By M. Chettibi

The interaction and galena flotation with xanthenes and dexanthogen regularities have been de-fined. So, using thermodynamic method of analysis, the thermodynamic stability of [galena - xanthenes - water] system and the behavior of lead xanthenes surface state in solution were devised. Thus, results of cared out calculations and experimental investigation completely coincide with-out depending on witch product of sulfur oxidation is formed in the solution. In additional, was obtained quantitative physico-chemical models for the necessary xanthenes concentration of lead sul-fide complete flotation in the tuning fork of: at ?? values from 7.0 up to 9.0 (or at the formation of lead carbonate PbCO3 ) and at ?? values from 9.0 up to 12 (or at the formation of lead hydro carbonate Pb3(OH)2(CO3)2 Physico-chemical models derived can be used as the criteria for functional units of automation systems to control and regulate the flotation process in mineral processing plants.

Jan 1, 2014

By S. M. H. Haddad, M. Saghaeian, R. Hejazi

"Due to limited water resources in mineral processing plants, increasing the efficiency of iron tailing dewatering system in order to obtain more usable water is very important. In this research, flocculation process, as one of the best method for water recovery, was investigated by using one organic cationic and three anionic types of flocculants with different dosages (10, 20, 30 g/ton) and iron ore tailing slurry (8 % w/w solidity) in series of graduated cylinders and obtained results were compared. it is observed that for tailing sample, the anionic flocculants have a significant effect on the settling rate of solid particles compared to the cationic types. Furthermore, effects of temperature (10, 23 and 43 ºC) and pH (2, 7 and 12) on the rate of settlement and turbidity was studied by utilizing the best flocculant. Findings showed that by increasing the amount of flocculant dosage, sedimentation rate went up and turbidity decreased. Comparison the out-put data of tests indicated that at temperature 23 °C and pH=7, the best results for both of faster settling rate and producing more clear water were reached. It should be considered that lower temperature has a more negative effect on the sedimentation rate and overflow water quality. So it will be predicted that for cold seasons, the consumption of the flocculant powder would be higher than the moderate or warm seasons. Also, coagulation/flocculation was evaluated by applying organic cationic coagulant added to anionic flocculant in three different times. Different ratios of coagulant to flocculant was examined (70%:30%, 50%:50%, 30%:70%) as well. Overall, utilizing coagulant had desirable influence on sedimentation experiments and obtaining high quality water. 1- INTRODUCTION In mineral Factories, among the important processes, solid-liquid separation process due to limited resources of water is very important and operates on iron ore tailing in settling tank as thickener in order to gain clear water for preventing water loss and applying again in plant units (Ciftci and Serhat Isik, 2017). Iron ore tailing include inharmonious compounds of iron oxides, silicates and aluminum-silicates. The percentage of solid in the tailing usually changes between 5 and 10 percent (Dash et al., 2011). One of the major problem about dewatering of tailing in thickener is solid-liquid separation of slurries with high stability because of fine particles. It means that rate of sedimentation is very slow and recovered water quality is inappropriate. This issue can be solved to a large extent by factors such as pH control, ionic strength and flocculation/coagulation process which results in aggregation of particles so that settlement by gravity is happened (Dash et al., 2011)."

Jan 1, 2018

By F. Q. Dong

According to the principle that should be originated from nature, compatible with nature, used in nature and back to nature and based on conception of designing of eco-material, the author combined the ideas of material, environment, zoology and healthy. Properties of natural mineral materials were used to produce micro-aggregate elements by bionic method, so its components and function could accord with living environment. Eco-mineral functional materials which can adjust, purify and optimize the microclimate were reviewed. The authors pointed out the multifunction, com-pounding, the compound characteristics and integration regularities of micro-aggregates. It was the first time in the world to put forward the ?gene? technique or ?material chip? technique of manufacturing function micro-aggregates and eco-function elementary materials. The results of this re-search supported by the national ?863? Hi-tech Project, mainly including the high-efficient air purifying mineral compound material indoor, the clay elementary antibacterial materials, the masonry cement/coating/putty/compound with preventing radon radiation, environmental friendly composite functional coatings, mosquito repellent and healthcare material and zeolite-based energy-saving composite materials, were introduced. Finally, the foreground of mineral materials in the field of future advanced eco-friendly materials was also discussed.

Jan 1, 2014

By G. Bonifazi

Mining activities belong to human history, they are lost in the mists of time. They usually impact on large portions of the territory, both directly (exploitation areas and logistic activities directly related to exploitation) and indirectly (exploited material handling, processing and storage areas). As a result, at the end of mine life cycle, dismissed areas usually cannot be directly re-utilized without efficient and well addressed rehabilitation actions. Main goal of the proposed approach was to analyze the results obtained when a set of procedures, based on the collection and the analysis of remote sensed data, is developed to evaluate the effect of rehabilitation of land contaminated by extractive industry activities and to perform a monitoring and registration of the environmental impact of such operations by the application and the integration of modern information technologies, as Earth Observation (EO) and Geographic Information Systems (GIS). The study was developed in the framework of the EU-Asia program of the European union (EXTRACT-IT Project-Contract No: CN/ASIA IT&C/006 (89870): Application of Information Technologies for the sustainable management of Extractive industry activities) and it was addressed to three different dismissed mine areas in India, Thailand and China, respectively. The results, in terms of methodologies selected, strategies applied and results obtained, are described with particular reference to Fuxin coal mine area in China.

Jan 1, 2014

By Kari Niiranen, Andreas Fredriksson

LKAB (Luossavaara-Kiirunavaara AB) is operating iron ore mines, concentration plants and pelletizing plants in Northern Sweden. Geometallurgy, which combines geological and metallurgical information is not a new way of thinking at LKAB, but rather a revised and updated version of an old working process. A project called "Silica in the Mine" which started in 2007, was an important reason to set a new focus at the geometallurgy. The target of the project was to develop a simplified method in laboratory scale to predict SiO2 grade in the magnetite concentrate in Kiruna and further predict the physical properties of the crude ore with respect to processing characteristics. The connection between mineralogy and products properties have started to be even more vital and necessary to examine due to the future exploiting new iron ore deposits. Geometallurgy at LKAB can be described as a mental and strategic framework where the Research and Development department (R&D), and others within the organization of LKAB, aims towards the connection of the minerals-production-products. It could in its basics be called "research & development", but it must be clarified that changes have been made, mainly due to the development on the instrumental analysis side. LKAB’s idea is to work quite broad, with internal educations, an active working process in ongoing projects, together with external parties (such as universities), with several PhD-projects and an upgrading on the instrumental side at the LKAB Research & Development department. This paper is a summary about the concept Geometallurgy at LKAB and some of the actions within its framework.

Jan 1, 2014

By C. L. Tang

Parts of the wastewater are reused directly and the rest moderately purified and reused, so the utilization rate of wastewater of the whole processing plant reaches 100 percent. At the same time, beneficiation indicators have been improved stably, and great economic and social benefits have been achieved.

Jan 1, 2014

The status quo of ecological rehabilitation in metal mine in China and progress in the technology for ecological rehabilitation are presented, including soil reconstruction, soil improvement, plant selection. The present and future research fields are suggested: basic theory of ecological rehabilitation, operative technology of ecological rehabilitation, new technology application research and ecological rehabilitation plan, management and policy.

Jan 1, 2014

By S. F. Ye, L. Xiao, Y. L. Wang, P. W. Han

"Copper anode slime is a precious secondary source for the recovery of silver. However, current recovery process are constrained by either sever pollution or high cost. To cover the drawbacks of current process, this research employed a novel strategy by using the manganese dioxide as the oxidant in acid solution, which avoided the generation of sulfur dioxide while high silver extraction rate was achieved. The effects of manganese dioxide, sulfur acid concentration, stirring speed, temperature and leaching time on silver extraction rate were investigated. The silver recovery reached to 91.68% under the conditions of 1.2 g manganese, 2.0 mol/L H2SO4, 300 rpm, 80 °C and 6 h. INTRODUCTION Copper anode slime is generated from the electrolysis refining of copper and is extremely precious for its containing noble metal such as silver (Chatterjee, 1996; Amer, 2003; Yldrm et al., 2014; Syed, 2016; Wang et al., 2017). Therefore it is of great significance to extract silver from anode slime for the full utilization of resource. Pyrometallurgy is the most mature process for the extraction of silver because of its stability and adaptability (Hait et al., 2009; Zhao et al., 2010; Gao et al., 2017). However, it also suffers the drawbacks of high operating cost, low extraction rate of silver and severe pollution of smoke dust (usually containing lead and arsenic) (Ludvigsson and Larsson, 2003). To cover the drawbacks of pyrometallurgy process, more and more attentions are giving to the semi-hydrometallurgy process which usually includes a pretreatment process of sulphatising roast or low temperature oxidizing roasting (Tishchenko, 1964). After pretreatment, the refractory silver bearing phases (silver selenide, silver sulfide and silver) are converted into readily leached forms which are often extracted by ammonia, sodium sulfite in alkaline solution (Valiuniene et al., 2010; Wojciech, and Kitka, 2017). Despite its relatively high extraction rate and low investment, it still has the disadvantages of releasing harmful gases since the sulfur dioxide are generally generated in the pretreatment process. In addition, the use of ammonia can easily lead to a leaking into the atmosphere once not carefully dealt with (Aylmore and Muir, 2001). As for silver recovery by sulfite leaching, the consumption of sodium sulfite is rather high which often results in a pipe blocked (Yang et al., 2006)."

Jan 1, 2018

By Carlos de F. Gontijo

The flotation of quartz particles was studied over the particle size range from 0.5 µm to 1000 µm and for advancing water contact angles between 0º and 83º. Flotation was performed in a column and in a Rushton turbine cell. Particle contact angle threshold values, below which the particles could not be floated, were identified for the particle size range 0.5~1000 µm, under different hydrodynamic conditions. The flotation response of the particles, either in a column or in a mechanically agitated cell with a similar bubble size, was comparable. Turbulence plays a role, as does bubble-particle aggregate velocity and bubble size. The stability of the bubble-particle aggregate controls the maximum floatable particle size of coarse particles. For fine particles, the flotation limit is dictated by the energy required to rupture the intervening liquid film between the particle and bubble. Flotation of very fine and large particles is facilitated with small bubbles and high contact angles. These results greatly extend our earlier observations and theoretical predictions.

Jan 1, 2014

The air recovery from a flotation cell is the fraction of inlet air which overflows the weir as un-broken bubbles. The air recovery is an important factor in froth phase phenomena; such as gangue entrainment and froth recovery. Increasing the air recovery, results in a higher recovery of attached mineral particles. Air recovery can be measured experimentally on plant using image processing of the top surface of an overflowing froth. The air recovery is directly linked to froth stability and the bursting rate of the bubbles at the froth surface, making it very difficult to predict. Experimental results show a very strong correlation between the superficial velocity of the inlet air and the superficial velocity of the air leaving the cell through the froth surface due to bursting, calculated from the experimentally measured air recovery. This correlation holds over multiple banks from different plants. Development of a power law equation around the inlet air velocity and the bubble solids loading on the froth surface allows the superficial air velocity through the top surface of the froth to be predicted, and from this the air recovery. This model is valid for use when operating beyond the peak in air recovery.

Jan 1, 2014

It is well known that the crushing and grinding steps in the mineral processing of ores represent a substantial proportion of total energy, cost and carbon emission in mining. For instance a recent study calculated that 36% of the energy consumed by gold and copper producing mines in Australia was attributable to comminution (Ballantyne et al, 2012). Understanding this component of a business is essential in a world seeking to lower production costs, improve earnings and reduce its carbon footprint. The issue commands the attention and support of industry leaders in the mining sector, government, equipment manufacture, engineering design and research organizations. Furthermore, several researchers have often stated that globally, comminution processes consume between 3-4% of the world?s electrical energy production (Daniel and Lewis-Gray, 2011). In 2009-10, Australia?s Federal Government Energy Efficiency Opportunity (EEO) participants in the mining sector used 336.5 PJ, representing approximately 6 percent of Australia&apos;s total energy use. It is evident that the current practices of breaking rocks in tumbling mills are relatively inefficient (Fuerstenau and Abouzeid, 2002). Research and improved engineering design has established that a range of improved blasting, crushing and grinding techniques and flow sheets may lower project costs and carbon footprint. These include relatively simple process flow sheet strategies such as gangue rejection or pre-concentration prior to size reduction, a better combination of grinding technologies (both current and new systems), and selection of coarser grind sizes where ore and waste mineralogy allow. Yet, despite this systematic and detailed research, the industry remains somewhat reluctant to implement these strategies. CEEC (Coalition for Eco-Efficient Comminution) was established in 2011 to support knowledge sharing and change in an area of high-energy consumption for the global mineral industry. CEEC is a not-for-profit industry company, funded by grants from world wide industry companies, whose mission is to accelerate knowledge and technology transfer in the field of energy-efficient comminution. The key benefit to the mining sector arising from CEEC?s activities will be an increase in the rate at which more energy-efficient comminution data sets, processes, and technologies are developed, demonstrated, shared and applied. This will contribute directly to the industry?s target of reducing operating costs and carbon emissions. CEEC International Ltd and JKTech Pty Ltd teamed together to facilitate the inaugural CEEC Workshop, in June 2012. The purpose of the workshop was to produce a roadmap to provide guidelines for how (1) operations can achieve best EEC practice in the short to medium term, in collaboration with vendors, engineering companies and other service providers, and (2) what R&D is needed to achieve paradigm change in EEC in the medium to long term, e.g. 75% reduction in comminution energy in 10 years.

Sep 1, 2012

By J. C. van Dyk

In a previous study by Van Dyk, et al., (2006) and Van Dyk et al. (2006), a FactSage model was developed to understand the chemistry and interpret mineral matter transformation during a fixed bed counter-current gasification process. It was concluded that the FactSage model developed, compared with HT-XRD experimental results and that the FactSage thermodynamic modeling sup-plies insight into specific mineral reactions and slag formation. The specific value for Sasol in using FactSage, in combination with HT-XRD is that it can be used to analyze equilibrium conditions for reactions occurring between inorganic and organic materials together, as well as to provide insight into mineral transformation and slag formation. The purpose of the present study was to improve the current FactSage modeling approach, by combining specific zones in the gasification process. This can improve and speed-up the interpretation of mineral matter transformations and flow properties of reacted mineral matter in coal and assist in identifying and quantifying slag formation in the gasifier operation at temperatures not reflected by normal AFT analyses. The updated and improved FactSage model compared favorably with the original model as well as with HT-XRD results and thus will be able to supply results in a faster and more convenient manner. In the new FactSage model, supported by HT-XRD experimental findings, it is indicated that feldspar formation (including anorthite) correlated with slag formation at temperatures around 1000°C and no slag formation in the base case coal was observed in the drying and devolitilization zone, as was to be expected. Feldspar is one is the mineral species which has the lowest AFT causing the most slag-liquid formation and forms probably as a product between the SiO2, Al2O3 and Ca-containing species. In the gasification zone it was clear that slag-liquid formed at a temperature of 1000°C, with a decrease in the feldspar content. Mullite formation was also observed in the base case sample in the temperature range 1000°C and 1100°C. The decrease in the amount of SiO2 at 1100°C is related to the formation of mullite, but also that the slag-liquid phase also contains an amount of SiO2 in the molten form.

Jan 1, 2014

By I. Baltov

The Chelopech Mine, located in Central Bulgaria, is one of Europe?s largest underground copper- gold mines, currently mines and processes approximately one million tonnes of ore per year. Copper concentrates containing gold and silver with significant arsenic content are produced and sold on the world markets. The operation was acquired by Dundee Precious Metals in 2003. A modernization program for the Mine and Plant has since been in progress to increase both production and mechanical reliability, and also to optimize metallurgical recoveries. Since then, mine output and plant throughput have doubled, plant availabilities and utilization have increased significantly, and overall metallurgical performance for copper and gold improved. The paper presents the systematic approach for obtaining and analyzing data, communicating it, and making suggestions for changes to the technological parameters and flowsheet in order to maximize metal recoveries. These studies have correlated the ore characteristics (particle size distributions, metal assays, and Cu and Au mineralogical and phase analyses) with the actual plant performance (kinetics, recoveries, and throughput). Cu recovery by size has been calculated from the mineralogical analyses of feed, concentrate and tails, with the most significant losses being identified in terms of fraction and phase recoveries. This has provided the recommendations (some of them tested in plant) for changes in the grinding and flotation circuits.

Jan 1, 2014

By A. Vilinska

Microorganisms have a tremendous influence on their environment through the transfer of energy, charge, and materials across a complex biotic mineral-solution interface. Recent developments in biotechnology have not only aided hydrometallurgical leaching operations but also shown great promise in mineral beneficiation processes. The adhesion of bacteria on minerals alters the surface properties relevant to flotation and flocculation of minerals. The biomodification of mineral surfaces occurs through the attachment of microbial cells, oxidation reactions and adsorption or chemical reaction with the metabolite products. Several types of heterotrophic and chemolithotrophic bacteria have been successfully applied in flotation and flocculation processes for the last two decades. Al-though the potential of microorganisms in minerals beneficiation has been realised by several re-searchers from their laboratory investigations, the studies were mostly confined to pure mineral systems and there is hardly any sincere effort to apply the methodologies on ores. This paper presents a brief summary of the literature in bioflotation and bioflocculation, and attempts to outline new dimensions of research for a practicable application of this technology in mineral industry.

Jan 1, 2014

By R. Mukherjee

Consistency of Run-Off-Mine (ROM) quality plays an important role in mineral processing which is not very often talked about. The major impediment is limitation of sampling ROM ore, which makes processing plants to run without any realtime feedback on ore quality that comes in. The process of direct determination of Run-Off-Mine (ROM) ore quality is expensive and time consuming as drawing and preparing representative samples from blasted muckpiles are constrained by large sample size and inherent heterogeneity in terms of size and chemistry. In absence of techniques for direct measurement of quality, monitoring and control of ROM, feed to the processing plant at Joda East Mine, like all other iron ore beneficiation plants worldwide, is largely based on blasthole sampling and subsequent chemical analyses of blastcone chips. While such indirect methods proves to be more accurate for representing whole of a mining block or blasted muckpile (~30-50KT/blast), it is indeed a challenge to ascertain and predict day to day input quality for a part there off. This eventually leads to a gap between predicted and actual ROM quality, resulting in difficulties in process control, in turn, and leading to wide swings in product quality. Hence, it is imperative to bridge the gap between predicted and actual ROM quality by arriving at means, which ensure consistent plant feed grade to deliver consistent output. The paper discusses an efficient and affordable alternative for effective prediction of ROM alumina which has been developed by integrating blasthole quality database in GPS based Truck Dispatch System (GPS-TDS) at Joda East Mine. Initially, GPS-TDS has been installed for optimizing production parameters only, but this development has helped in further utilization of GPS-TDS for real time quality monitoring by improving ROM grade prediction and scheduling from several ore blocks in active mining areas. Keywords:run-off-mine (ROM), blast hole, feed grade, GPS-TDS

Sep 1, 2012

By A. P. Liu

Semi-industrial test on fine products of Meishan dressing plant was carried out with type RP80/25 high pressure roller mill produced by Homburg Corporation of Germany, and the influences of such factors as energy consumption, water containing, throughput and circulating load on rolling effect were investigated. Closed circuit experiment result showed that Meishan iron ore could be suitable for powder grinding with high pressure roller mill, and energy consumption of the operation was declined by 25%~30%, which was favorable for energy-saving, increasing production efficiency and improving grinding effects. According to above experimental results, this paper put forward the technical proposal of application of high pressure roller mill in Meishan, and pointed out some technical problems which needed to be settled urgently in technology disposal.

Jan 1, 2014