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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

By Gurubasayya Swamy

This paper presents the performance study of sag mill in the processing of gold ore. Deterioting ore grade and high demand of metals has tremendously influenced the SAG mills. Today?s high capacity Semi-autogenous grinding (SAG) mills expand vast amounts of energy and in doing so consume tons of shell liners and steel balls, while processing ore. Semi-autogenous (SAG) mill performance is influenced by ball charge, feed properties, shell, grate, and pulp lifter design. In the performance study of SAG mill, based on the results obtained it can be observed that SAG mill performed better at feed size +4 inch and grinding media consumption 0.90kg/mt. In the present study the effect of crusher bypass on SAG mill performance, an immediate drop of throughput ranging from 10-20tph is observed. Keywords: sag mill, pulp lifters, grinding media, energy, consumption, throughput

Sep 1, 2012

By Peter Ay, Bodo Müller, Jens Markowski, Manfred Kanthak, Florian Logsch

"Presently the global commodity situation for non ferrous-, precious- and rare metals is characterized by a strong increase in consumption and a simultaneous shortage of materials derived from primary sources. So the use of secondary raw materials gains is important due to economic and ecological reasons. Non Ferrous-, precious- and rare earth metals were detected in household waste (Municipal solid waste, MSW) for years. In MSW-treatments plants NF-metals are actually mostly separated from dried fractions. The separation of these metals is carried out with the aim of removing particles which disrupt further processing. A selective enrichment of individual non-ferrous metals has not been carried out previously. The separated fractions contain mixtures of Al, Cu, Zn, Pb, Sn, alloys, precious metals (e. g. Au, Ag, Pt) and rare metals (Ga, In, Nd etc.) along with considerable amounts of contaminations. The R&D project "NE-Rec" selectively processes the coarsely separated non-ferrous-metal-conglomerates increasing the concentration of targeted metals. Metals and metal mixtures are concentrated by sorting steps and the impurities are discharged from the process. Still contaminated precious metals are then subjected to a wet-chemical treatment. So metals can be specifically brought into solution or can be precipitated to separate unwanted components (inerts, polymers, foreign metals). Further the relevant metals will be concentrated by thermal-metallurgical processes. The technology, developed in the R&D project, enables identification, separation and processing of non-ferrous metals, precious metals and REM in household waste and transfers them into further processable individual fractions."

Jan 1, 2014

By G. V. S. Murthy

Beach Placer Ilmenite is an important source for production of titanium metal, titania slag and pigment grade titanium dioxide. Besides, these well known applications for which Ilmenite is mined and processed, there are other emerging processes that are being tried for obtaining highvalue products. Synthesis of Ilmenite based materials for varistor applications and direct electrochemical reduction of Ilmenite to produce ferrotitanium are two such attempts being discussed in this work. In this paper, recent efforts undertaken to study the electrical and magnetic characteristics are discussed. Ilmenite, FeTiO3, is one of the mixed-valence transition metalbearing minerals, inwhich Fe can be in two different oxidation states, Fe2+ and Fe3+.. Similarly, Ti can be in Ti3+ and Ti4+.Ilmenite is inherently suitable for making Varistors, which are devices, used for limiting the transient voltage surges in a circuit. Varistors produced from Ilmenite can withstand harsh environments seen in nuclear reactors and outerspace. Electrochemical reduction of Ilmenite can be used to prepare ferrotitanium directly without any reductant. The process essentially involves removal of oxygen from the mineral through electrolytic action using calcium chloride as electrolyte and graphite as anode. At a temperature of 950°C, it is shown to be possible that all the oxygen can be removed from the Ilmenite sample, which passes through the electrolyte, to form CO/CO2 at the anode. The process has immense potential for cost effective production of titanium metal as well. Results of the above developmental works are presented in this paper. Keywords: beach placer ileminite, varistor applications

Sep 1, 2012

By Hermann Wotruba, Lars Weitkämper

"Dry coal dressing was popular during the 1950.s and 60.s in many parts of the world. The devices mainly used were air jigs and air tables.The increase in ash and moisture content of run-of-mine coals due to the wide advanced mechanisation of mining mechanisation during and after this period led to that pneumatic devices being unable to treat run-of-mine coals with the desired efficiency. Since the 1960.s almost all new coal preparation plants have been based on wet processes that are highly efficient in terms of coal recovery and their ability to handle damp and sticky run-of-mine coals. (Frankland, 1995)However, water is becoming increasingly costly and the disposal of fine products, containing most of the water, is an environmental concern. There would be significant cost savings and a lower total energy consumption if coal could be cleaned dry. Efficient dry coal treatment would be an interesting solution in desert, arid or cold areas.In Germany one dry coal dressing plant is in operation. The process and the advantages and disadvantages are presented below.Further on new developments in the field of dry density separation of coal are reviewed and analysed. Test results of new dry coal separation methods e.g. new developed air jig and magnetic separator are reported."

Jan 1, 2003

By S. M. Bradshaw, C. Dorfling, F. Ngandu

"Selenium removal and platinum group metal (PGM) recovery from copper sulfate leach solutions form an integral part of platinum producers’ base metal refinery operations. Recent studies found that substantially higher PGM recoveries can be achieved if excess thiourea instead of sulfurous acid is used as precipitation reagent; however, the impact of the proposed process on downstream processes was unknown. The objective of the current study was therefore to investigate the effects that excess thiourea and residual selenium present in the rich copper sulfate electrolyte have on copper electrowinning. This was achieved by performing cyclic voltammetry tests using a platinum rotating disk as working electrode, a graphite auxiliary electrode and a saturated calomel reference electrode. A synthetic copper sulfate electrolyte containing 0.01 M Cu2+, 1 M H2SO4 and varying amounts of selenium (20 – 150 mg/L) and thiourea (10 mg/L and 100 – 300 % excess) was used. The results obtained have shown that both thiourea and selenium interact with the cupric ion cathodic reduction reaction. Thiourea polarized the working electrode and lowered the efficiency of the cupric reduction reaction. Tests on the solutions with high selenium concentration showed simultaneous reduction of copper and selenium, which led to copper selenide formation. Nodule formation on the deposit surface also became significant at higher selenium concentrations. Based on these results, it was concluded that precipitation of PGMs from the copper sulfate solution with excess thiourea is not feasible due to the detrimental effect on downstream electrowinning operations.INTRODUCTION During the high pressure oxidative leaching stage in a typical base metal refinery (BMR) circuit, selenium, tellurium and some platinum group metals (PGMs) are dissolved along with the desired copper ions. The impurities (selenium and tellurium) may pass to the copper electrowinning circuit where it can result in the formation of nodular copper electrodeposits or reduced current efficiency. The presence of PGMs in solution, on the other hand, increases the precious metal inventory and potential losses of the operation. Currently, sulfurous acid is widely used for selenium and tellurium precipitation from copper sulfate leach solutions. Sulfurous acid is capable of reducing cupric ions to cuprous ions; the generated cuprous ions then react with Se4+ and Se6+ to precipitate selenium as a copper selenide (Bello, Dorfling, 2014). Recent studies have, however, proposed the use of excess thiourea as a precipitating agent for the removal of selenium and tellurium; it has the advantage of improved PGM recovery in the Se/Te precipitation step (Lottering, Eksteen et al., 2012; Mulwanda, Dorfling, 2015)."

Jan 1, 2018

By C. Raghu Kumar

Hydraulic or teetered bed separators (TBS) are finding new avenues for application in the field of mineral processing. Floatex Density Separator (FDS) is a hydraulic/teetered bed separator capable of operating at high tonnage due to its advanced instrumentation. FDS/TBS is being used in Indian mineral sand industry for classification and segregation of different minerals. The purpose of this paper is to provide details on the performance of the plant scale FDS in recovering the chromite from feed (below 1mm size). Historically this feed has been processed using hydrocyclones and spiral classifiers; however, there is a strong trend now to employ teetered bed separators, thus allowing significant changes to be made in the plant for improving process efficiency. In the present work, the performance of the plant scale FDS is described in terms of partition curve (yield, cut size, classification efficiency/Ep) for different combination of process variables and also in terms of metallurgical grade and recovery. It is found that, efficient classification can be achieved at a maximum cut size of 380 µm with and the imperfection is also reported as low as 0.16. The grade of the underflow product is enriched as maximum as 52.2% Cr2O3 from a feed assaying 40.4% Cr2O3.

Sep 1, 2012

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 Kirsten Corin, Margreth Tadie, Michael Nicol, Cyril O’Connor, Jenny Wiese

"The recovery of base metal sulfides has been emphasized in the study of the flotation of platinum group minerals (PGMs). However, in some ore bodies such as the Platreef of the Bushveld Complex, sulfide minerals do not make up the majority of the more significant PGM mineralization. It is therefore important to develop a fundamental understanding of how non-sulfide and sulfide PGMs respond respectively to the current reagents being used in the flotation of these minerals. The interactions between platinum and palladium sulfides and tellurides with the thiol collectors, ethyl xanthate and diethyl dithiophosphate, have been studied using the electrochemical techniques of mineral rest potential and voltammetry measurements. The differences in the interaction between the two types of minerals with these reagents were of key interest. Rest potential measurements indicated stronger electrochemical interactions of the minerals with ethyl xanthate than diethyl dithiophosphate. These measurements also indicated that there are different forms of oxidized collector present on the mineral surfaces after interaction with ethyl xanthates. Voltammetry measurements support these observations and suggest differences of adsorption on Pt and Pd sulfides than on Pt and Pd tellurides. Voltammetry also showed that there was minimal electrochemical interaction between the Pt and Pd minerals and diethyl dithiophosphate."

Jan 1, 2014

By Erico Tabosa, Meng. Jun, Kym Runge, Matthew Brennan, Weiguo Xie, Dee Bradshaw

Turbulence and its distribution are of great importance in flotation cell design as they affect suspension of particles, air dispersion and particle-bubble collision rates, which in turn determine flotation performance. However, there is no mature technique to measure turbulence in three phase (liquid-solid-gas) systems such as in flotation cells. In this article, the authors present two new approaches that are suitable for measuring turbulence distribution in three phase systems and validate their applicability. The first technique uses a piezoelectric vibration sensor (PVS) to measure fluid kinetic energy standard deviation and the second technique applies electrical resistance tomography (ERT) to measure conductivity variation at a measurement position in a flotation cell. For the PVS technique, calibration of the sensor was performed to determine the values of parameters that were needed to calculate the force applied to the sensor. Then measurement was conducted in a 60L batch flotation cell and the results were compared with LDA measurement. This demonstrated that the piezoelectric sensor signal provides a good representation of fluid kinetic energy standard deviation at the position of measurement. For the ERT technique, conductivity distribution data was processed to give conductivity variations, which were then used to calculate fluid kinetic energy standard deviation at the measurement position. The spatial distribution of turbulence obtained by performing multiple measurements at different positions in the 60 litre batch flotation cell was found to agree with the PVS measurement results. These two techniques are potentially powerful tools for turbulence measurement in flotation environments, enabling a clearer understanding of turbulence’s influence on flotation performance to be determined.

Jan 1, 2014

By A. S. Broesder

"With depletion of global ore deposits, there has been an increasing industry trend towards mining of lower average grade deposits in order to meet global demand, resulting in increased processing cost, energy usage and water usage. Consequently the industry is seeking pre-concentration technologies to reduce costs, increase production in existing operations and potentially enable the economic mining of previously uneconomical deposits. This pre-concentration can also advantage downstream processing and metal recovery. CSIRO has developed a large scale magnetic resonance based technology for the rapid quantitative detection of selected copper, iron and arsenic minerals in bulk ore. The technology is suited to measurement on large primary conveyors for enabling “pod” based sorting. The approach used in high tonnage sorting is to not sense and divert individual rocks, but to instead measure groups of rocks (“pods”) carried continuously on a single primary conveyor that can be diverted by conventional mechanical means. Bulk ore sorting operates by removing barren ore pods from a stream of crushed ore based on a bulk sensor measurement at a pod resolution of ~1 – 10 tonnes. The sorting process is based on the intrinsic variability of grade during the mining process that often occurs at the few tonne scale, and for instance, is common in many porphyry copper deposits. The MR technology has been proven in the laboratory for a wide range of copper, arsenic and iron minerals. A full scale prototype sensing system has been demonstrated in a trial at an Australian copper mine. Implementation trials of commercial MR based bulk sorting systems are progressing during 2018.INTRODUCTION An increasing trend in the mining industry is the exploitation of larger lower-grade deposits to meet global demand. Low-grade deposits involve increased processing cost, energy and water usage and increased tailings. There is therefore growing interest in technologies that enable more efficient extraction of low grade deposits. Water intensity of mining activities in a context of water scarcity, and the environmental and health implications of mine tailings are existing challenges, which are only made worse by the progression to lower grade orebodies. There is therefore also an interest in safer, cleaner and less wasteful extraction and production to ensure community well-being and environmental resilience."

Jan 1, 2018

By Homero Delboni, Mauricio Guimarães Bergerman

"At the regrind or secondary grinding stages of metal ores, usually the concern about the energy efficiency is extremely important. In general, the specific energy consumption at this stage is higher than in the primary stages of grinding. In addition, it has been observed a tendency of finer grinding in the new projects of metallic ores, due to the finer mineral liberation, which leads to an increasing capital and operational costs. In Brazil, during the last 10 years, regrind P80 sizes of approximately 40 to 20 ?m have been necessary in all new iron and copper plants. The use of conventional ball mills, adequate for primary grinding, can result in low energy efficiency with products below a P80 of 50 ?m. This paper presents an overview of the regrind circuits in Brazil that operate with vertical mills and the results of industrial surveys at selected vertical mill circuits. Where possible, comparison is made between the plant results and the design criteria and laboratory regrind tests used for the mill sizing."

Jan 1, 2014

By Pawel Strzalkowski, Marta Baszczynska, Urszula Kazmierczak

The paper presents issues related to interference of mining activities with the environment. Exploitation of mineral resources causes primarily a modification of the landscape. All of the negative impacts on environment are short-lived and last as much as it takes to exploit the raw material. After the mine closure reclamation is necessary during which all aspects that reduce harmful effects of the mining activities on the environment must be taken into account. Current ways of reclamation allow recreating natural environment, which is different from the original and enriched in diverse new values. This requires propositions of new forms of converted land development through a detailed analysis of technical, natural, planning, economic and social sphere requirements. Before making final decisions regarding selection of direction of reclamation, a thorough analysis of the key factors has to be carried out. All steps related to the implementation of the reclamation project are shown in the paper using Limestone Mine "Górazdze" located in the south-western part of Poland as an example. This paper also presents an analysis of current ways of post-mining reclamation towards agricultural and forestry landscape, along with our own suggestion for their extension in order to preserve biodiversity. For choosing optimal solutions the most relevant criteria were considered: existing natural values and possibility of their protection. Taking into account the economic and social aspects, supported by natural potentials, implementation of tourism and recreation in this area were proposed. It was shown that this proposition would not interfere with the current trends of the natural landscaping. Finally, after completion of reclamation and land development in the considered mine area, creation of a geo-park was proposed along with appearance of geotourism in the area. To illustrate the proposed forms of post-mining land development in the form of maps, an ArcGIS(ESRI) software was used.

Jan 1, 2014

By E. Lee

Cone crushers are widely used within the mining and aggregate industries for the size reduction of minerals, ores, and rock materials. In mining applications for example, the product from cone crushers is often fed to HPGRs or directly to mills in the subsequent grinding circuit. An improved cone crusher performance can therefore result in an overall improved and more efficient comminution process. The objective of this paper is to systematically study a number of different ways of applying compressive crushing. By mathematically modelling these different crushing concepts and then theoretically optimizing crushing sequences accordingly, each concept can be studied and evaluated. In addition, aspects concerning whether or not the results are mechanically or practically achievable are considered. This study thus explores the advantages and disadvantages of different crushing concepts. In this paper, four different theoretical crushing concepts are presented and studied. The results show that in terms of interparticle crushing, optimal crushing sequences with varying compression ratios can be replaced by easier implemented series of constant compressions without significant deterioration. It is also shown that that considerably better performance is obtained for crushing sequences with both breakage modes. The subsequent comparison between such concepts indicates that different approaches can achieve the same results, and that the different concepts are comparable. It is further concluded that interparticle crushing should be kept to a minimum if fines generation or energy consumption is to be minimized, and that each of the studied concepts presents different challenges for implementation. Keywords: compressive crushing, cone crusher, optimization, modeling, crushing concept

Sep 1, 2012

By K. W. Stöckelhuber, A. Wenger, H. J. Schulze

"An important elementary step of the flotation process is the forming, drainage and rupture of a thin intervening liquid film between bubble and mineral particle.After the encounter of the bubble with the solid surface a wetting film is formed. The initial thinning of this film is driven by the capillary pressure inside the bubble. When the film has reached a certain thickness rupture can take place.There are two possible mechanisms describing this process:-, Growing fluctuation waves (spinodal dewetting) on fluid interfaces under the influence of any kind of attractive forces (electrostatic, van der Waals). -, Nucleation inside the film.Metastable wetting films on negatively charged, hydrophobic glass surfaces (gaseous phase methylated), or on hydrophilic, positively charged glass surfaces (with Al3+ ions), have been analysed by means of the kinetics of film thinning according to the Reynolds law. These experiments demonstrate that both mechanisms can be responsible for the rupture of a thin wetting film. In the case of hydrophobic surfaces the nucleation mechanism is preferred; in the case of opposite charged silica surface the capillary waves mechanism due to an attractive electrostatic double layer force between silica and air bubble takes place.Hereby the existence of a long range hydrophobic force. on a hydrophobic surface can be excluded. The apparent interaction can be explained by the presence of gas nuclei formed on heterogeneous surface sites. The results provide deeper insight into the mechanisms of wetting film stability, adhesion process in flotation and droplet coalescence."

Jan 1, 2003

By M. A. Hampton

The surface oxidation of sulfide minerals in aqueous solutions is an important sub-process in sulfide flotation and hydrometallurgy, but a full understanding of the oxidation process and products is still lacking. Many oxidation pathways and products involving elemental sulfur, metal polysulfide, metal-deficient sulfide and sulfate have been proposed, confirmed and argued. In this paper we provide further insight into the surface electrochemical behaviour of galena in aqueous solutions. For this research we have developed a novel experimental system, that combines chronoamperometry and AC-mode AFM surface imaging, which allows for in-situ, synchronized electrochemical control and examination of oxidative surface morphology. At pH4, the morphology of elemental sulfur (detected by ex-situ Cryo-XPS) formed on the oxidizing galena surface depends on the electrochemical potential pathway. In multi-step chronoamperometry (i.e. four potential steps from 0 mV to + 350 mV) the sulfur forms as nanoscopic domains, whereas in single-step chronoamperometry (i.e. one potential step from 0 mV to + 350 mV) sulfur forms as a heterogeneous layer. In each case the oxidation is controlled so that the number of electrons (coulombs) passed per unit area is the same, therefore the amount of sulfur produced is also the same. The differences in morphology with electrochemical potential pathway are explained using a nucleation and growth model. The formation of sulfur on the surface increased both advancing and receding contact angle of galena, but the morphological changes induced by different electrochemical potential pathways did not significantly alter the hydrophobicity of the surface. Keywords: galena, lead sulfide, oxidation, Atomic Force Microscopy, electrochemistry, collectorless flotation, hydrophobic

Sep 1, 2012

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 Cheng Gan, Gui Xiahui, Li Shulei, Cao Yijun, Liu Jiongtian, Wu Lun

Flotation rate constant is an essential parameter in the flotation process. The fine coal sample utilized in this investigation is anthracite from the Shenhuo mine in eastern China. Fine coal flotation rate tests were conducted to compare the flotation rate constant at constant power input with that at gradually increasing power input. Results indicate that the flotation rate constant decreases with the flotation process and increases as the flotation energy is increased. In addition, the flotation rate constant is close to the maximum value. The increasing trend of the flotation rate constant gradually slows down as the flotation energy input increases.

Jan 1, 2014

By Francisco Vicuña, Miguel Becerra, Nelson Iglesias

"The following article presents the development of a dynamic tool for the estimation of Jb/Jc rate (ball filling level / total load filling level) of a SAG mil operating in a single stage mode. Using the methodology detailed in this article, it is now possible to have a dynamic estimation tool in the operation, which enables strategic decision making and achieving a continuous development in process optimization. The estimating of the load filling level (Jc) was conducted using a power model, which in this case corresponds to the C-Model developed by (Morrell, 1993) that was calibrated by measuring the load filling levels (Jc) and balls (Jb) using the FARO laser scanning technology by means of Grind-Out and Crash-Stop procedures during the year 2013 and 2014. Finally, to estimate the dynamic filling level of full charge, Jc, three independent models were developed that allowed to feed the adjusted power model: •,SAG mill discharge grate slot wear model •,SAG mill internal volume wear model •,Ball filling level estimation model."

Jan 1, 2014

By Anuttam Patra, Romain Bordes, Andreas Fredriksson, Tommy Karlkvist, Krister Holmberg, Kota Hanumantha Rao

Almost all of the flotation reagents used today were discovered by continued application of empirical methods and/or trial and error experimentation. Moreover, with the metal-ion specific approach used so far, it is difficult to separate the minerals containing the same constituent metal ion. A critical assessment of molecular recognition processes involved in biomineralization suggested the possibility of using reagents which are surface specific. The concept that the molecules consisting of two or more functional groups having appropriate spacing between those so as to achieve structural/stereochemical compatibility during interaction with the mineral surface exhibit structure-specificity is thought to be extended to the design of specific collectors in flotation processes. In the present study, for the first time, a rational design of surface active molecules, and thereby the recognition of crystal faces (of minerals) by these molecules through structural and stereochemical matching is being utilized successfully to selectively float various minerals. For this purpose, carboxylate-based collectors (for mineral specific flotation of calcium minerals) as well as xanthate-based collectors (for mineral specific flotation of sulphide minerals) with a fixed alkyl chain length but having two functional groups with varying geometrical distances (separated by a spacer of one, two and three carbon atoms) between them have been synthesized. In this article, we have discussed the design, synthesis, purification of these novel mineral specific collectors as well as their important solution parameters in relation to flotation processes.

Jan 1, 2014