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By O. Guven, I. Karaagaçlioglu, O. Ozdemir, M. Çelik

In this study, the effect of morphological properties such as shape factors and roughness of the glass beads on their flotation efficiency were determined using image analysis and profilometer methods. There is a considerable correlation between the shape factors, surface roughness and flotation behavior of the glass sample. These results indicate that as the particle shape is away from roundness and smoothness, it acquires more hydrophobicity.

Jan 1, 2014

By Rhulani F. Maluleke, Francis W. Petersen, John H. Marsh, Johann de T. Steyl, Allan Nesbitt

"Pressure leaching of chalcopyrite and nickeliferrous pyrrotite at temperatures between 105 and 200 ºC has been proposed as a potentially viable route for the extraction of mineral elements from sulphide concentrates. In general, these concentrates contain iron, and the economic success of the processes is partially dependent on the choice of the environmentally acceptable iron-removal technique. One of the most widely used methods for the removal of iron from sulphate liquors is precipitation as hematite, goethite, or jarosite. The nature of the iron precipitate formed dictates downstream dewatering and residue treatment and disposal options. However, a better understanding of iron precipitation under the defined process conditions would consequently be of benefit in process design and optimisation.This study investigated the precipitation of iron in the autoclave at temperatures between 105 and 200 ºC. The effects of temperature, acid concentration, iron concentration, and the presence of other metal cations on the nature and composition of the precipitates were determined."

Jan 1, 2003

By Peter Ay, Vincenz Mehlstaubl, Satyanarayana Narra

"This study gives an insight into non-destructive testing methods suitable for porosity analysis at a small scale, firstly summarizing relevant state-of-the-art technology and pending patents, secondly realizing and documenting the start-up of the VHX-2000 digital microscope by the manufacturer Keyence and thirdly demonstrating practical application with the extended analysis of three fundamentally different agglomerates for which important application-related parameters are determined. Various analysis procedures on the different agglomerates the efficient and timesaving operational features of the digital microscope are outlined. Firstly an analysis of flax fibre agglomerates determines the process conditions best suited to produce agglomerates with specific properties by determining sphericity, cubicity, density and porosity as well as fibre damage and alteration. Secondly the production of iron-hydroxide - hemp-fibre agglomerates serves to obtain information on porosity values as a result of a cauterization of the fibres. The third analysis provides estimations of porosity values for acid-treated lignin agglomerates. Measurements were carried out with compact dry agglomerates and with soaked, expanded agglomerates, determining factors for total water carrying capacity. Practicability of non-destructive testing by digital microscopy is demonstrated and explained concerning the applications in this study by obtaining definite structural findings about the analysed agglomerates. Information on its operation is made available by a practice-oriented manual for the VHX-2000 digital microscope. Further suggestions for more in-detail analysis results with different instruments are given."

Jan 1, 2014

By M. Kargar Razi

According to the unique properties and many applications of nano silver powder, it was prepared from acid leaching tail solution. The low value residual gold and silver ions were occurred with fellow heavy metals as pollutants (Fe2+, Cu 2+and Zn2+) in acid leaching tail solution in Mouteh gold mine in Iran. Preparation of nano silver particles was achieved in two steps: first, by addition of ammonia as separation step and second by using different reagents as precipitation and extraction steps. Different controlled parameters were including pH, residence time and temperature, mixing time, and reducing reagents to metals molar ratio. Acid leaching process was carried out with sulphuric and nitric acid via suitable reductants. In order to remove copper, zinc, and silver ions from solution, all of the conditions were controlled. The optimum conditions for preparation of nano silver powder with less than 90 nm were pH 10.5, hydrazine/methanol to silver molar ratio of 3 to 4, and reduction time of 5 min in 45 °C. The results were evaluated via SEM, A.A and UV- Vis spectroscopy analytical methods.

Jan 1, 2014

By L. X. Yu

As is known, the oxidized antimony and antimonate are hard to treat. A new combined mineral processing flowsheet which is controlled in grinding and classification ?bulk floatation?gravity separation is adopted to dispose of gravity-separated tailings (antimony content: 1.48%; oxidization rate: 68.92%) in Muli Antimony Mine, the grade of floatation antimony concentrates is 32.64%; the grade of gravity-separated antimony concentrates is 26.99%; the combined grade of floatation and gravity-separated antimony concentrates is 30.85%, and the total recovery of antimony is 70.64%. Adopting the new mineral processing technique have solved the problem of over grinding of antimony ore by controlling grinding and classification, recovering effectively the sulfide antimony and the easy floatable oxidized antimony of fine size by bulk floatation, recovering effectively the oxidized antimony which is hard to float by classified gravity separation. This is a great breakthrough in the mineral processing technique of the recovery of the oxidized antimony. At present, favorable economic benefit has been obtained from the application of this processing technique in Muli Antimony Mine.

Jan 1, 2014

By X. W. Zhang

Mica plate is broadly used in electric industry, production of man-made mica paper plate is in-creasing. The problem coming with is that large quantities of leftover materials unable to be re-cycled are produced during cutting and molding of mica plate productions. The leftover materials are always abandoned as crabs, which not only pollute the environment but also waste our resources. The study intends to find a new measure to decompose and to reuse the mica plate leftover materials so as to create a new production process of mica plate, which is clean and does not produce crabs.

Jan 1, 2014

By Behzad Vaziri Hassas, Firat Karakas, Mehmet Celik, Onur Guven

Since dewatering is a costly process, removal of moisture from relatively fine size lignites is an important industrial problem. As the lignite gets finer, the presence of micropores and relatively low hydrophobic nature of lignite lead to trapping of large quantities of water in the coal matrix. Lignites used in power stations need to be dried to a certain degree of humidity before it is transferred to the combustion chamber. It is generally wise to dewater coal as much as possible by physical means before it is dried. However, dewatering cost in some cases may be prohibitive. Thus, sometimes removal of even little percent moisture may be of great help in such operations. Surfactants have been used to increase the efficiency of coal dewatering. It is crucial to select appropriate type and amount of surfactants in order to get higher efficiency. Since the hydrophobic characteristic of coals increases with increasing the coal rank, dewatering of bituminous and anthracite can be accomplished using low HLB surfactants (Oily), however, these surfactants are not efficient in the case of low rank coals like lignites and brown coals. It is suggested that adsorption of low HLB surfactants on high rank coals is governed by Acid-Base interactions rather than electrostatic and van der Waals forces. Since this characteristic in lignites is not strong enough, low HLB surfactants could not be effectively adsorbed on low rank coals to make surface more hydrophobic. In this paper, a special set-up has been designed to study the effect of high HLB surfactants on dewatering of fine lignite particles. It is shown that high HLB surfactants function more efficiently on low rank coals than low HLB ones.

Jan 1, 2014

By F. Karakas

Water based paint formulations consist of some industrial minerals with quantities varying from 20 to 50 %. Quality of paint is directly related to these minerals used as pigment or filler in the production. Titanium dioxide is the most important and expensive pigment in paint formulations. Other minerals such as calcite and calcined kaolin are used as filler and mainly as a substitute for TiO2. Consequently, particle-particle interactions including adsorption, coating and size distribution of pigment mixture directly affects the paint quality. In the present paper, a new type of pigment mixture for possible use in architectural water based paints was developed through grinding. The effect of different types of grinding methods on physical properties of TiO2 and calcite mixture and the quality of paint produced by these mixtures have been revealed. Three different types of mills; conventional ball mill, vibratory ball mill and high-speed attritor were used for grinding of TiO2 and calcite. Viscosity, zeta potential and particle size distributions were used to characterize the pigment mixtures obtained upon grinding. The quality of paint was evaluated by standards based on both wet and dry paints such as viscosity, density, opacity and gloss. The paint produced with the pigment mixtures prepared in vibratory ball mill and high speed attritor showed improvement in physical properties particularly in the distribution and dispersion of mineral particles. Keywords: grinding, pigment, paint, TiO2, calcite

Sep 1, 2012

By Dezhou Wei, Cong Han, Shuling Gao, Wengang Liu, Yanbai Shen

The recycling schemes of copper mineral to a copper raw ore produced in China is investigated in this paper, of which is aimed at copper concentrate‘s grade is over 26.00% and recovery is over 90.00%. The primary copper mineral the raw ore is chalcopyrite and the main gangue minerals are quartz, orthoclase, albite, clinochlore and phlogopite. There are four useful metal elements contained in the copper raw ore, which are Cu, Pb, Zn, Au and Ag, and the grade of each is 3.75%, 0.01%, 0.11%, 0.31 and 483.5 g/t. Two floating recycling schemes and its corresponding flotation reagent system were determined. The results show that calcium oxide, sodium carbonate and sodium sulphide were used as regulators, sodium n-butylxanthate was used as collector and terpenic oil was used as frother in two floating recycling schemes are effective. The open-circuit test’s results show that the copper mineral contained in raw ore can be effective collected, and both concentrates gotten through two schemes are up to grade.

Jan 1, 2014

By John A. Herbst

Professor A.M. Gaudin and his students at MIT were dedicated to understanding the fundamentals of mineral processing and as a consequence were constantly searching for better quantatative descriptions of size reduction, liberation and mineral separations. I have had the good fortune of meeting Professor Gaudin and working with many the modeling pioneers who followed him. I have observed first hand the refinement of mineral processing models as they increased in realisticness moving up the steps of the pyramid (see figure below) from pure empiricism to the current pinacle of physics based models. During this journey our industry benefited significanbtly as model prediction errors were reduced from ± 20% to ± 1%. Unit operation and plant simulations improved in accuracy and speed of calculations.

Sep 1, 2012

By J. Gong

Fine mineral particles pose two challenging problems in froth flotation, i.e., ineffective recovery of fine hydrophobic particles and mechanical entrainment of fine hydrophilic particles. The first problem has attracted much research effort while the second problem has received much less attention. We have recently proposed a method to deal with mechanical entrainment, i.e., utilizing the flocculating power of polymeric depressants to flocculate fine gangue particles and making the flocs big enough so that the mechanical entrainment of these particles can be reduced or eliminated. In this paper, we report results on the use of polyethylene oxide (PEO) in controlling quartz gangue in the flotation of sulphide ores. PEO was found to flocculate fine quartz and lower its entrainment. It was also found to modify air/water interfacial properties and acted as a frother, which could increase gangue entrainment. Nevertheless, when used at starvation dosages, PEO was found to significantly improve the grades of the floated sulphide concentrates.

Jan 1, 2014

By Rong Fan, Andrea Gerson

"The small recovery of Ag, often in the order of 50%, by traditional flotation and leaching process strategies is closely related to the complicated and heterogeneous nature of Ag-bearing minerals with Ag typically being associated with numerous minerals within any given ore-body. Moreover, grain sizes may be extremely fine with micron-scale common. In order to design cost-effective Ag-bearing mineral flotation and leach recovery strategies it is firstly necessary to characterise the speciation of Ag and its correlation with other elements, e.g., Cu, As and Sb, within the ore matrix and process streams. The traditional QEM-SCAN analytical approach can prove problematic for some mineralogies due to difficulties in recognising degrees of crystallinity, polymorphs, complex solid solution series, high value trace element mineralogy, very fine grained materials; and the requirement for a comprehensive data base. Moreover, there is difficulty ‘seeing’ either surface films or surface contaminants which can both lead to poor flotation performance. There is therefore clearly a need to develop confirmatory and complementary approaches when these uncertainties arise. Synchrotron X-ray microprobe analysis provides a powerful tool for the mineralogical characterisation of finely segregated heterogeneous Ag-containing materials. These measurements enable comprehensive characterisation of the Ag-bearing components using synchrotron microprobe X-ray fluorescence mapping (µ-XFM), X-ray diffraction (µ-XRD) and X-ray absorption spectroscopy (µ-XAS). Further analytical strength is provided by principal component analysis of laboratory ToF-SIMS data which enables the statistical identification of correlated surface species enabling examination of surface chemical characteristics responsible for mis-reporting of Ag containing components within flotation streams. We describe the application of these techniques to a selected Ag-containing feed and tail and demonstrate how these compliment and extend traditional analytical methodologies."

Jan 1, 2014

By Sergey Ulianov, Arkady Senchenko, Alexey Shvets, Arkady Bakotin

"This paper contains description of research results of technology development for copper recovery from weathered tails of iron processing plant. The predominant host mineral that contains valuable component is chalcopyrite occurring in its free form and in associations with ore and rock-forming minerals. Copper grade is 0.26-0.30%. Emulsion inclusions of chalcopyrite in pyrite and sphalerite were noted. Major problem is low copper recovery (30-35%) by flotation. When studying chalcopyrite in primary concentrate it was determined that the surfaces of many chalcopyrite grains are covered with oxide films which prevented collector attachment onto them. Second issue was deep association of chalcopyrite with pyrite and sphalerite. Sulfidizing reagent addition did not help to reach the required level of copper recovery to concentrate. In the result of research performed the technological flowsheet was developed including preliminary treatment of head material in a special unit aiming at oxide films removal, followed by copper rougher flotation on head size tails, crude concentrate regrinding and a number of cleaner flotation operations. After the treatment of weathered tails according to the flowsheet developed, copper recovery to flotation concentrate became 71.53%, at 23.46% copper grade. The suggested technology allows one to solve the issue with treatment of technology-related copper-containing stockpile material, as well as to include the ores where copper is represented by sulfide minerals covered with oxide films into processing."

Jan 1, 2014

Over the last four years, a major collaboration between CSIRO-MIS, UCT and JKMRC has produced two significant advances in the modelling of comminution. The Universal Comminution Model (UCM) uses parametric SPH/DEM studies of comminution and separation devices to calibrate mathematical models which are suitable for industrial use. The Virtual Comminution Machine (VCM) uses the same computationally intensive techniques based on discrete element modelling (DEM) and smoothed particle hydrodynamics (SPH) to directly model any comminution device by combining a CAD file describing the machine design, sophisticated ore characterisation methods and advanced particle scale flow and breakage simulation. The UCM should be useful for process analysis and optimisation of existing equipment and circuits while the VCM should make a major contribution to the evaluation and development of new machines. Progress to date is encouraging with several processes now well described using DEM. This paper also reports on progress towards combining DEM for particles with a realistic slurry model based on SPH for different types of comminution devices. In due course, this combination should allow accurate modelling of particle transport in wet mills to be combined with DEM models.

Jan 1, 2014

By D. Renda

With thise Process of obtaining a solid fuel which is both ecological clean and has a high calorific value by a two-stage method of enriching preferably type lignitic coals to remove a high content of all sulphurs, incuding organic sulphur, which method comprises converting the coal to a semi-coke from followed by magnetic separation. In the Experiments given the best results the washed lignite coal in the West-Turkey, Tavsanli- Region, size -3.35 mm on dry basis. In the microscopic studies of the brigh-thin cross-section taken from the samples of sulfur min-erals pyrite in the dimension of 2~50 micrometers and melnicovite 10 micrometers particles. An thermal treatment an semi-coking themperature between 370°C to 650°C give the best Result of 480 °C. The oxidation and decomposition of sulphur minerals pyrite and melnicovite in lignite coal proceed the iron oxides Fe2O3 and pyrrhotite FeS on the surface layer. The Magnetic Seperator (Rare Earth Magnetic Separator, REMS) is capable this two form of sulphur, including organic and inorganic sulphur, in semi-coke and resulted in the magnetic-fraction in REMS. The non-magnetic-fraction remove total sulphur by 68 %, ash by 44 % and increase the upper calorific value in 15 %. The clean lignitic coal can be utilized in human or energy power stations.

Jan 1, 2014

By V. Vogt

During the phosphating of car bodies containing aluminium, the employed phosphating chemicals zinc, manganese and nickel are, for thermodynamic reasons, only used to a limited extent for the desired surface coating. The major proportion of these metals is discharged together with the incidental cryolite-containing phosphating sludges and the rinse water. Commissioned by the German Federal Ministry of Education and Research (BMBF), the Institute of Mineral and Waste Processing, Waste Disposal and Geomechanics at the Clausthal University of Technology has developed a two-stage process for the production-integrated recovery of the dragged out chemicals and for closing the rinse water cycle for Audi AG. During the first stage, the phosphating chemicals are recovered by means of leaching. In the second stage, the rinse water is treated by means of electroflotation followed by an ion exchanger.

Jan 1, 2014

By R. S. C. Smart

Surface chemical factors, including the balance of hydrophobic (e.g. collectors) and hydrophilic (e.g. oxidation products, precipitates) species, are major control determinants in flotation rates of specific minerals and therefore grade and recovery. There are a number of challenges involved with the surface analysis of different mineral phases from process streams in a flotation facility. The first is to collect samples that are representative of the process and retain their surface chemistry prior to introduction into the instrument. The second challenge in studying the surface chemistry of specific minerals is to find reliable methods of mineral phase recognition. In surface analysis of mineral particles, confident mineral selection can be difficult with many multi-metal minerals and with precipitated, adsorbed, reacted and contaminant species in the outermost molecular layers. The third challenge is to provide a statistical surface analysis of multiple grains of the same mineral. Methods to achieve these aims are described. Principal component analysis (PCA) of ToF-SIMS data provides improvement in phase recognition, particle selection and associated variations in surface species. Specific examples from both lab and plant operations, demonstrate that this technique can be utilized to differentiate surface chemical factors promoting (hydrophobic species) or inhibiting (hydrophilic species) flotation. A study of copper ion transfer (inadvertent activation) from chalcopyrite to pyrite and sphalerite clearly identified a statistical difference in copper intensities between the sphalerite and pyrite phases corresponding to their flotation response. The PCA analysis applied to concentrate and tails samples collected from the Inco Matte Concentrator demonstrated extensive CuOH and NiOH transfer between chalcocite and heazlewoodite minerals. The statistical analysis has been able to identify mechanisms controlling recovery and selectivity. High intensity conditioning (HIC) tests in which sphalerite was separated from a complex sulfide ore gave a 5% increase in the overall Zn recovery. The PCA/ToF-SIMS statistical analysis revealed the discriminating depressant action of adherent aluminosilicate (gangue) fine particles and adsorbed ions on the surface of sphalerite grains. HIC conditioning resulted in the removal of these gangue fines improving surface collector attachment efficiency.

Jan 1, 2014

By Dilip Kumar Mohanty

In today?s world, Sustainability is the key issue before the mankind. With the ever-increasing population & unimaginable boost in industrial growth to cope up with a steady increase in demand and fast change in life style of a human being, the natural resources are exploited to such an extent that the very existence of living beings in this earth planet is threatened. In such devastating situation, the concept of Sustainability emerges out as a great savior. This concept focuses on minimum/ judicious use of natural resources, thereby preserving the resources for future generation while meeting the bare minimum requirement of the present generation. For an emerging economy like India, Mining and Mineral based industries form the back bone of our economic development. Thus, sustainability of mining and mineral processing industry has a far reaching impact on sustainable economic development of our nation. While at a macro-economic level, we have to strike a balance between economic development vis-à-vis socio-economic & environmental impacts, Industries have to ensure judicious and frugal use of natural resources by making use of energy efficient plants & machineries and adopting befitting technology for reduction & recycling of waste. In the context of the above, it would be interesting to look into the sustainability measures taken up by National Aluminium company (Nalco) at its Crushing & conveying plant at Panchpatmali Bauxite Mine, which is incidentally Asia?s largest Bauxite Mine. In the backdrop of the above stated facts, in this paper the authors make an attempt to bring out the sustainability issues in areas of energy conservation, environmental impact/pollution vis-a-vis mitigation measures adopted in crusher & conveyor plant of Panchpatmali Bauxite Mine & CSR / peripheral developmental activities undertaken by Nalco to mitigate the socio- economic impacts. Keywords: sustainability, energy efficiency, recycle, csr, peripheral development

Sep 1, 2012

By Richard A. Williams

The mineral processing community have been amongst the pioneer developers and early adopters of key platform technologies in analytical methods, chemistry, physical separation and advanced modelling. Fundamental research will continue to have a significant impact driven by the continued development of sustainable practices. Major drivers and challenges for change in our industry in the next two decades include: reduction in energy uses in processing; discovery of new energy materials; adoption of green chemistry routes; safeguarding of water resources; and demonstration of adherence to best practice at all times. With increasingly global mining enterprises, the provision of internationally accepted benchmarks for performance will continue to drive the creative process. This lecture highlights major opportunities around a new paradigm of Multi-scale Measurement coupled with Multi-scale Modelling, based on advanced sensors, communications and computing. Connecting real-time measurement sensors with dynamic simulation models opens up new horizons for visualising the process behaviour from an experimental and theoretical basis. Examples are given of the potential of this methodology and its implications for better design.

Jan 1, 2003

By X. S. Yuan

With a demand for increasing energy efficiency and a need for improving bitumen recovery, a highly integrated solution for sustainable lease development of Aurora North of Syncrude has been proposed and implementation plans are underway. Flocculation and thickening technology as an important component of the integrated solution provides Syncrude an opportunity of rapid heat recovery from tailings and more flexible tailings closure and reclamation options. Flocculation of fine-particle suspensions by polymers is a non-equilibrium process whose performance is strongly influenced by physical and chemical variables. While polymeric flocculants are frequently used to establish the chemical conditions favorable for flocculation, the actual performance of a flocculation process generally depends more on the physical variables, such as the hydrodynamic conditions in mixing the flocculants and slurry. In order to study the effect of hydrodynamic conditions on flocculation of Syncrude fine tailings, a standardized laboratory test procedure called power flocculation has been developed in comparison with the conventional manual mixing methods. It is shown that the agitation speed and time in conditioning the flocculant solution and the slurry have a profound effect on the flocculation performances measured by initial settling rates, supernatant clarity and sediment density. It was found that the optimum bench test conditions for power flocculation of Aurora fine tailings with a sand-to-fine ratio (SFR) of about 1:1 are conditioning of the flocculant solution and the tailings slurry at 250 rev/min to 300 rev/min in 20 s to 40 s. The test results are inter-preted with a flocculant adsorption/redistribution kinetic model that helps understanding of the effect of hydrodynamic conditions on flocculant adsorption, floc formation and floc growth.

Jan 1, 2014