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By Weiran Zuo, Emmy Manlapig, Fengnian Shi

The effect of metalliferous grains on electrical comminution efficiency was investigated by comparative experiments using natural rocks and synthetic samples. The result indicated that the existence of metalliferous grains affects the breakage probability and product size distribution of electrical comminution. On average, metalliferous grains increased the breakage probability of particle in the first pulse discharge by 55% and generated finer product at the coarse end. As a result, particles with metalliferous grains exhibited higher energy efficiency than that without metalliferous grain in electrical comminution. A positive linear relation between product fineness and specific energy in electrical comminution was observed. With the assistance of numerical simulation on the electrical field distribution of ore particle, the role of metalliferous grains in electrical comminution is confirmed and the mechanism of metalliferous grains effect is elucidated. Understanding of the effect of metalliferous grains on electrical comminution is important to evaluate the feasibility of applying electrical comminution to ores with different mineral composition, and to understand the breakage behavior in electrical comminution.

Jan 1, 2014

By A. V. Rasskazova

"The oxidized and mixed ores are processed by heap leaching. Primary ores with high gold content are floated. In recent years mining of primary ores with the low gold content (up to 4 ppm) has increased. Extraction of gold from these ores by floatation is technologically ineffective. Gravity concentration is ineffective for fine gold particles because of their floatability. The research objective was assessment of the viability of processing gold-bearing ore with combined gravitational and hydrometallurgical methods and testing of recovery of metals from a gold-copper oxidized ore chloride-hypochlorite leaching solution. The advantage of chloride-hypochlorite lixiviant is the low cost of reagents which is produced by the electrochemical synthesis of NaCl solution with the addition of HCl. The adsorption of chlorine compounds by a mineral matrix and its ability to oxidize the refractory ore components and allows for the application of chloride-hypochlorite systems for gold recovery for both oxidized and primary ores. The complexity and problem in using a gold–chloride system is the strong adsorption of gold–chloride complexes onto mineral surfaces, such as goethite, quartz, and alumina. In preliminary testing, gold recovery from gravity circuit gold bearing concentrates processed by agitation leaching in chloride-hypochlorite solution, gold recovery has reached up 82% after 4 hours of leaching. Chloride-hypochlorite leaching of copper-gold oxidized ore with preliminary processing by sulfuric acid provided for 94 % gold recovery to solution. Understanding of ecological hazard of cyanides is the motive power of researches in the field of search non-cyanic chemistries to provide for technologically and economically effective solvents of gold. Soluble compounds of chlorine with a suitable oxidizer are one of the alternatives to cyanides. Basic researches of gold extraction by chloride-hypochlorite solution have shown high rates of gold recovery.INTRODUCTION Because of the continued and growing environmental concern for the use of cyanide for gold processing, interest for the use of non-cyanide lixiviants, especially with halides has renewed recently (Tran et al., 2001; Ferron et al., 2003; Bhaghalha, 2007). Leaching solutions based on halides (chloride, bromide and iodide) are viable alternative to cyanide (Kwang et al., 2008). The major disadvantage of the chlorine–chloride system is the high reactivity of chlorine in reaction with sulfide and gangue carbonate minerals. It is believed that only high grade materials may be treated by chlorine–chloride systems economically (Baghalha, 2007). Another important problem of the application of gold–chloride complex is that it tends to be rather unstable and may re-precipitate upon contact with a reductant, such as sulfidic minerals of ore. It is well known that Au(III)–chloride hydrolysis species are strongly adsorbed by goethite, quartz, and alumina (Machfsky et al., 1991). To minimize adsorption of gold–chloro complexes, it works best to minimize the adsorption time."

Jan 1, 2018

By A. Mainza, I. Govender, J. Waters

"The study of the properties of mineral processing suspensions is important in understanding how a circuit might behave. As soon as the predominantly dry ore enters a wet milling stage the ore properties undergo changes as a ‘slurry’ is created. Slurries can be classified in terms of their physical properties (particle density, solids concentration, particle size and size distribution, particle shape), and their flow properties such as rheology. Slurry flow regimes are classified into true homogeneous, pseudo homogeneous, heterogeneous and fully segregated, and only true homogeneous and pseudo homogeneous suspensions can be characterized by their flow structure. A class of the heterogeneous regime are the so-called dense phase or settling slurries - those which result in a clear water surface on standing, although they may approach a pseudo homogeneous state if suspended for a sufficient period of time. They are usually extremely difficult to characterize by their rheological properties alone and the rheological characterization of these slurries has always posed a problem, especially at higher concentrations. Previous rheological studies have focused on the individual concentrator units dealing with milling, classification, pumping, flotation, fine grinding, thickening.In this work an attempt was made to characterize two ore types (copper and a Platreef platinum ore) using a custom built Paterson and Cooke tube rheometer, at concentrations up to 43% by volume. After applying a turbulence correction, results showed Bingham plastic behavior. A conventional vane rheometer was then used to compare the rheological behavior of platinum concentrator streams. A size criteria was used to identify any rheologically dominant streams."

Jan 1, 2014

By M. Panayotova

Most of the quantity of the water soluble xanthates, used in mineral flotation, is consumed in the process. However, the residue amounts are water contaminants downstream the mineral processing operations and can be toxic to aquatic biota at concentrations of 1 mg/L. In order to be able to discharge water from tailing ponds to natural water bodies the concentration of xanthates has to be decreased. The present paper studies the uptake of potassium ethyl xanthate by directly modified with copper and lead ions natural zeolitic rock, without passing through zeolite transformation into homoionic form. Modified zeolite exhibits high, comparable with powdered activated carbon of chemical purity grade, capacity to remove potassium ethyl xanthate from model wastewater, with pH in the range of 7?9 and pollutant concentration in the range of 10-150 mg/L. The pollutant immobilization is fast. Both Cu and Pb modified zeolite behave as selective with respect to xanthate in the model wastewater, and Cu-modified zeolite possesses higher selectivity. The equilibrium is best described by the Freundlich equation. Keywords: xanthate, wastewater, modified zeolite

Sep 1, 2012

By Kaustubh Joshi, Pradip, Beena Rai, Venugopal Tammishetti

"Rapid depletion of high grade iron ores coupled with the increasing demand for the blast furnace grade iron ore in recent times has shifted the research focus on the development of appropriate technologies for the utilization of low - grade alumina rich iron ore slimes. These slimes are currently being dumped into tailing ponds owing to their high alumina content. Typical constituent minerals present in the Indian iron ore slimes are hematite, goethite, gibbsite and kaolinite. Considering the fine particle size distribution (<37 microns) in the slimes, selective dispersion-flocculation seems to be one of the most appropriate process which has been explored by us. We present our successful results on a natural iron ore slime sample obtained from one of the mines in India. We have been able to achieve a concentrate assaying >67% Fe, and <3% Al2O3 and 2.8% loss on ignition (LOI) from the slime sample assaying 60.4% Fe, 7.7% Al2O3 and 5.45% LOI with an Fe recovery of 62-69% simply by adjusting the pulp pH. We have scaled up the process to a semi batch scale as a prelude to commercialize it for the beneficiation of low grade iron ore slimes."

Jan 1, 2014

By F. Burat

The present research covers the results of experiments carried out with high frequency vibration screen on dewatering of coal fines. In the tests, the addition of surface active reagents was studied employing a high frequency vibrating screen. To increase the efficiency of mechanical dewatering processes, ultrasonic treatment was applied along with surfactants and optimum dewatering conditions were obtained. The moisture content of the feed material was from 82.5% to 41% by the optimization of operation parameters including the angle of the screen, vibration frequency, feed rate and screen opening size. Optimum parameters obtained in dewatering processes carried out with the vibrating screen were kept constant and the effects of surface active reagents and ultrasonic treatment on dewatering were investigated. Finally, the moisture level of the material was further reduced from 41.0% to 37.66%.

Sep 1, 2012

By Nilmara Dias, Maria Margarida Martins, Maria Teresa Carvalho

"The heavy residual fraction of the mechanical and biological treatment (MBT) plants treating undifferentiated municipal solid waste is mostly composed by inert materials, such as glass, stones, ceramics and brick. Glass, appearing in significant grade and amount, is not recycled today due to the high content in the other materials, mainly stones. All these materials have approximately the same density but stones have significantly different shape from other materials particles. In this paper it is presented the research developed to eliminate stones appearing in the fine fraction (2.8-8 mm) of the MBT plants heavy residual fraction (MBTr) using a shaking table operated in dry conditions. Two different samples from two different MBT plants were used. Firstly, the samples were characterized (materials content and particle size analysis). Then, laboratory work was carried out to optimize the operation of the shaking table, by changing the machine parameters, deck slope and movement frequency. The study showed that it is possible to upgrade the product in glass. The best results, obtained with one single stage of processing, were 82% content in glass with 84% in recovery, in the glass concentrate, when the coarser fraction (-8+5.6 mm) of one of the MBT plants was used. With the intermediate particle size fraction (-5.6 + 4mm), the glass concentrate attained 74% content in glass with 91% recovery."

Jan 1, 2014

By Lei Pan, Roe-Hoan Yoon

"Direct force measurement for bubble-particle interaction has been difficult due to bubble deformation, which makes it difficult to know the separation distances between the two macroscopic surfaces. In the present work, we have developed a method of monitoring the deformation accurately, while directly measuring the interaction forces. In effect, we can ‘see’ bubbles interacting with mineral surfaces under different hydrodynamic and chemical conditions and determine both the hydrodynamic and surface forces involved. In the present work, a high-speed camera has been used to record the optical interference fringes of a thin liquid film (TLF) of water formed on a mineral surface. The recorded fringes are then used to reconstruct the spatiotemporal profiles, from which one can determine the hydrodynamic pressure using the Reynolds lubrications theory. From the forces directly measured in the present work and the hydrodynamic pressures obtained from the fringes, we have determined the disjoining pressure. The results show that air bubbles interacting with hydrophilic surfaces form stable TLFs with zero contact angles. The TLF formed on a hydrophobic surface thins fast, form a ‘pimpled’ film, and ruptures to form a finite contact angle. The new information obtained in the present work may be useful to better understand the role of hydrodynamic and surface forces affecting bubble-particle interactions."

Jan 1, 2014

By Thenepalli Thriveni, Seong-Young Nam, Nam-Il Um, Joobeom Seo

In the present work, we report a novel microstructure of synthesized scalenohedral PCC (precipitated calcium carbonate) without any additives by a simple and ecofriendly carbonation process carried out in a liquid-gas system on the crystal growth of the scalenohedral calcite phase. Especially, the process parameters of Ca(OH)2 concentration and CO2 flow rates were investigated to enhance the sensitivity of the process. The highest average length of the scalenohedral calcite was obtained at pH 6.0, temperature 450C, Ca(OH)2 concentration 0.2M, CO2 flow rate 80mL/min, and total volume 1L. The utilization of flue gas-derived CO2 from coal fired power plants could be a form of carbon capture and storage using carbonation reaction with scalenohedral PCC. Finally, the synthesized scalenohedral PCC was used as a filer for ONP recycling. We demonstrated all these experiemnts at semi pilot plant scale.

Jan 1, 2014

By C. H. Veloso

"Starch is the most widely used depressant in the reverse cationic flotation of iron ores. There is however, an indication from recent studies, that other polysaccharides may successfully replace them. When starches are used in the flotation of iron ores in the presence of quartz as gangue mineral, their strong adsorption on the surface of iron oxides can be explained by the molecular conformation between the available sites on the mineral surface and two hydroxyls of starches. However, when the gangue minerals are iron-bearing silicates, the strong interaction with starch can occur on these minerals since they have the same surface behaviour as iron oxide. In this work bench scale tests were conducted in order to generate scientific knowledge about other alternatives depressants for the flotation of iron ores. A magnetic pre-concentrate from a skarn iron ore processing plant was used as feed material for flotation tests. The reverse flotation approach was used to upgrade the iron content by removing complex ironbearing silicates. The depressants used in this study were: corn starch, dextrin, carboxymethyl cellulose (CMC) and humic acid. The tests were performed under different pH conditions in order to try to relate the efficiency of depression to the pH used during flotation. The results show the important role of pH as each depressant reached its best performance at different pH values. At alkaline pH the corn starch showed best depression performance while the humic acid is more efficient at pH close to neutrality.INTRODUCTIONIron corresponds to approximately 6% of earth’s crust composition (McDonough and Sun, 1995). It is the most used metal in our lives, some of its properties as resistance and facility to be shaped makes is replacement very difficult. The primary sources of iron on our planet are minerals. The iron-bearing minerals most commonly found in nature and economically exploited are magnetite [Fe3O4], hematite [Fe2O3], goethite [FeO(OH)] and siderite [FeCO3] (L O Filippov et al., 2014). These minerals are commonly associated with other minerals (most of the time not economically exploited) forming the so-called iron ore. Iron ore is the source of primary iron for the world’s iron and steel industries."

Jan 1, 2018

By M. Ito

Cobalt-rich ferromanganese crust and nodule ores from seamount areas contain volcanic and sedimentary rocks as substrate or nuclei and these ores require mineral processing to remove the substrate/nuclei rock before smelting. This paper reviews the results of jig separation and air table treatment for the coarse fraction and flotation and hybrid jigging for the fine fraction. Using these techniques substrate/nuclei rock was removed from the cobalt-rich ferromanganese oxide components. The mineralogical properties and metallurgical treatment methods including hydrometallurgical treatment of low grade ore is also reviewed.

Sep 1, 2012

By J. M. Ortiz, J. Haas, W. Kracht, G. Pamparana

This work explores the effect of ore hardness variability on the design of a solar photovoltaic system with battery storage and grid backup, to operate a semi-autogenous grinding mill (SAG). First, a case of two synthetic ore populations was studied, without any consideration of spatial distribution. The mean and variance of the ore hardness (measured in specific energy consumption, SEC) of both populations were subjected to a sensitivity analysis. The operation was evaluated with one and two stockpiles. The latter allows classifying according to ore hardness as a way to adapt the SAG energy consumption to the solar cycle. The results show that using two stockpiles allows achieving a larger autonomy (i.e. less energy imports) at lower total costs, especially when the difference of mean hardness between the two populations is large. The difference in variance (between the two populations) has a smaller impact on the design recommendations. Second, a case study was performed considering the spatial distribution of geometallurgical units. Two cases were considered: (a) brownfield, when there is historical information of the actual variability of the ore hardness; and (b) greenfield, when the system design relies mainly on geometallurgical modeling. Brownfield and greenfield planning result in similar sizing recommendations of the solar power plant, if precise drill cores are available. In this case, geometallurgical modeling is an effective tool for forecasting the energy demand necessary for designing the power plant.

Jan 1, 2018

By K. C. Corin, M. S. Manono, J. G. Wiese

"It has been suggested that hydroxo species, particularly those of calcium, selectively adsorb onto gangue minerals. Such species enhance the depressive action of carboxymethyl cellulose (CMC) onto gangue via an acid-base interaction between the positively charged mineral surface and the negatively charged CMC molecule. Thus, the hydrophilicity of gangue minerals is enhanced, preventing the dilution of the concentrate. However, as there is little evidence to support these claims it is important to investigate. Adsorption data and mineral surface charge analyses will allow a fundamental understanding into how electrolytes and their ionic strengths affect gangue-depressant adsorption. It is strongly anticipated that decoupling these effects will allow process operators to tailor their process water quality needs towards best flotation operating regimes and in the long run effect closed water circuits. Thus, using talc and pyrrhotite as proxies, this work investigates the influence of the ionic strength of process water on the adsorption of CMC onto minerals in sulphide flotation.INTRODUCTIONThe phenomenon of gangue depression in mineral flotation is of critical importance as regards the attainment of a required concentrate grade. This thus suggests that the depressant of choice has to have a highly selective affinity for the targeted gangue minerals. This would ensure the necessary prevention of gangue from reporting to the concentrate without inadvertently depressing the value bearing mineral. The chemistry of the environment regulates the manner in which gangue depression occurs. In sulphide flotation, polysaccharides are used as depressants of choice to depress naturally floatable gangue which may in the case of Merensky ores exist as talc. The two widely used polysaccharides in the South African context are carboxymethyl cellulose (CMC) and modified guar gum. It is suggested that polysaccharides depress gangue by rendering the surface of gangue hydrophilic or by preventing the formation of hydrophobic layers on gangue mineral surface, forming large gangue aggregates and thereby increasing their heterocoagulative nature (Shortridge et al., 1999)."

Jan 1, 2018

By John Ralston, Jona Addai-Mensah, Patience Mpofu

The flocculation and dewatering behaviour of kaolinite (non swelling) and smectite (swelling) clay dispersions has been investigated using hydrolysable metal ions Mn(II) and Ca(II) and anionic polyacrylamide-acrylate copolymer (PAM) at pH 7.5 and 10.5. A pH-dependent, specific metal ion adsorption behaviour, accompanied by a marked reduction in particle zeta potential and slurry shear yield stress, was observed to have a profound influence on the colloid stability of both types of clays. Due to the differences in the cation exchange capacity, the smectite clay dispersion required a higher amount of metal ions than kaolinite dispersion to produce similar effects. The adsorption density of the anionic PAM at the negatively charged clay particle surfaces correlated well with metal ion hydrolysis and adsorption behaviour, all of which had a strong effect on slurry settling rate and extent of consolidation. At pH 7.5 where Mn(II) ions hydrolyse, metal ion and flocculant adsorption densities were both greater in the presence of Mn(II) than Ca(II) ions. At pH 10.5, however, where Ca(II) ions begins to hydrolyse, higher adsorption densities were observed for Ca(II) ions in comparison with Mn(II) ions, as the latter hydrolysed completely and precipitated. The metal ion mediated flocculant adsorption led to improved hydrogen bond driven particle bridging and facilitated charge neutralisation flocculation mechanisms which significantly enhanced the dewaterability of both clay dispersions.

Jan 1, 2003

By Felipe Sepulveda, Edelmira Gálvez, Luis Cisternas

"In mineral processing, the recovery and/or concentration of the value components cannot occur in one operational stage, therefore requiring the use of separation circuits based on several flotation stages. The components to be separated are typically distributed at different concentrations and different particle sizes, resulting in different levels of recovery. Typically, more than one value component must be selectively removed by exploiting the differences in the components’ floatability at different pH values, pulp potential and particle size. Several methods for the design of these circuits are available in the literature, but comparatively few studies present circuit analysis tools or address the design of a multiple-product flotation circuit. In this study, global sensitivity analysis was used to analyze a flotation circuit with several products, such as copper, lead and zinc. This analysis was based on the Eureka mine concentrator plant. The analysis was performed for each of the sections of the circuit as an overall evaluation of the circuit. The Sobol’ method and the correlation method were used to evaluate the Eureka mine concentrator plant using the SimLab 2.2 software."

Jan 1, 2014

By Massimiliano Zanin, William Skinner, Owusu Clement, Jonas Addai-Mensah, Daniel Fornasiero

This paper highlights the importance of pulp aeration in the selective separation of chalcopyrite from chalcopyrite/pyrite mixtures of varying pyrite content (20-80 wt.%). Laboratory batch flotation studies and oxygen demand tests were performed to predict the optimum amount of air required for the selective separation of chalcopyrite from pyrite. The pulp oxygen demand was shown to increase with increasing pyrite content but decrease with time as more air is introduced into the system. Complementary batch flotation tests showed significant improvement in chalcopyrite flotation under moderate pre-aeration of the pulp. However, a continuous decrease of chalcopyrite flotation was observed under highly aerated conditions. The amount of air required to achieve maximum chalcopyrite flotation recovery correlated positively with the mass fraction of pyrite in the pulps. The greater the wt.% of pyrite in the chalcopyrite/pyrite pulp, the longer the aeration time required. The optimum aeration time was established as the time before which the oxygen consumption rate constant reaches a bottom plateau. Surface analysis (XPS) indicated that the continuous decrease in pyrite recovery observed with increasing aeration time was due to the formation of more iron oxy/hydroxide on its surfaces, the same species accounting for the decrease in Cp recovery after prolonged aeration.

Jan 1, 2014

By L. O. Filipov, N. E. Menad, A. Geneyton

"Zeta potential of synthetic monazites presenting various compositions were measured to investigate the effect of the main lanthanides substitutions on electrophoretic mobility and resulting IEP. The measurements are performed in a CO2 depleted and enriched solutions showing both reduced influence of monazite chemistry and strong influence of ions resulting from the solubilization and dissociation of CO2. The influence of oleic acid on the electrophoretic mobility of those monazites was also investigated. The influence of pH on oleate adsorption was studied using a bubble/particle adhesion system. Adhesion strength measurements were performed on pure synthetic monazite-(Ce) and monazite-(La). An extensive thermodynamic model of monazite in water was developed to highlight correlations between lanthanides hydroxides/carbonates species concentrations in the bulk solution and oleate adsorption. Based on electrophoretic measurements, advanced thermodynamic consideration and adhesion measurements, further details of the oleate adsorption model on monazite surface were proposed.INTRODUCTION Electrophoretic and potentiometric data on monazite and, a fortiori, other rare earth semi-soluble salts such as bastnaesite are extremely erratic (Chelgani et al. 2015). The isoelectric points measured with electrophoretic mobility methods range from 4.7 to 6.5 although sporadic data indicates an IEP (isoelectric point) far from that range. Different explanations are proposed in the literature to explain the IEP variability notably the numerous chemical substitutions that frequently occurred within monazite crystal lattice (Chelgani et al. 2015). Based on lanthanides speciation diagram, several authors highlighted the influence of specific lanthanide species on the flotation performance of rare earth semi-soluble salts when carboxylate or hydroxamate collectors are used. Although lanthanides ions have a great affinity for carbonates groups (Kragten et Decnop-Weever 1987), lanthanide (hydrogen) carbonates were not implemented in speciation diagrams. In this work, an advanced thermodynamic model is proposed to highlight correlation between flotation performance and lanthanide species predominance but also concentrations. Qualitative measurement of the monazite surface hydrophobicity are performed through tests of adhesion of coarse monazite particles onto bubbles. Since flotation and microflotation technics are highly influenced by hydrodynamic parameters, this method was investigated to obtain a sharp contrast between appropriate and inappropriate pH conditions. This paper is to investigate 1) the effect of lanthanides substitution on monazite surface properties through zeta potential measurements, 2) the mechanism of adsorption of carboxylates on monazite surfaces and 3) the effect of CO2 on monazite surface properties and carboxylates adsorption."

Jan 1, 2018

By Georg Unland, Thomas Wegner

"Different types of impact crushers use the physical effect of impact to crush rocks. The rocks can vary from soft to hard and from ductile to brittle but they should never be abrasive. Since the principles of impact crushing of larger rocks are hardly investigated these crushers are still sized rather by empirical than by scientific approaches.In order to investigate the principles of comminution by impact of large rocks a test rotor was developed and rocks of different dimensions were tested. The integrated measuring devices of the rotor enable the recording of impact forces and of absorbed impact energy with high resolution during the contact time.Since impact crushers stress the rock particles with a defined velocity the main crushing properties are gained as a function of the applied velocity and the particle size of the rock: likelihood of breakage, contact time, maximum crushing force, mass specific crushing work, surface related crushing ratio and crushed fragment shape distribution."

Jan 1, 2003

By Darryel Boucher, Raymond Langlois, Neil Rowson, Kristian Waters

The Knelson Concentrator is a centrifugal gravity concentrator composed of a high speed rotating bowl into which a mineral slurry is fed. The rotational motion creates a centrifugal acceleration up to an equivalent of 200 G. Under this acceleration, particles enter fluidised riffles along the side of the bowl, with the fluidisation allowing for the substitution of dense material for less dense. The separation mechanism is not fully understood and questions remain on the optimal residence time, slurry feed parameters and bowl surface profile to achieve a better separation. The positron emission particle tracking (PEPT) technique has been applied to record the motion of a -1700+1180 µm particle of a quartz-gold matrix, labelled with 18F radioisotope while it undergoes concentration inside a 3" laboratory scale Knelson Concentrator (KC-MD3) operated at 60 G. The slurry used was composed of quartz and magnetite. Particle trajectories during the first stage of the concentration process where the heavier particles centrifuge through the increasingly dense slurry towards the riffles of the bowl are shown with respect to time. This work reveals new information on particle motion inside the Knelson Concentrator and the results will be used for validation of developed separation model as well as optimisation of a centrifugal concentrator’s performance.

Jan 1, 2014

By M. Rudolph, D. H. Hoang, N. Kupka

"Froth flotation has been subjected to modelling since the 1930s and there is a large variety of approaches that intend to portray the entire process. Among these, three fundamental models could be considered exhaustive: the Pyke model [1], the Yoon model [2] and the Schwarz and Koh model [3]. The first model makes use of the generalized Sutherland equation collision model, the Dobby-Finch attachment model and its own stability model, the second model considers an extended DLVO approach for the attachment and stability whereas the third model makes use of computational fluid dynamics. Using a scheelite ore as a test case, a specific batch flotation test was repeated ten times and analyzed for chemical assays, mineralogical studies and froth properties. The detailed data are used to feed the three flotation models aforementioned in order to compare the outcomes of the three approaches, their capacity to reflect reality and to predict it. This article intends to pave the path towards reliable process models incorporating in depth mineralogy information, e.g. surface liberation, particle size and particle shape. KEYWORDS Froth flotation fundamental models, scheelite, automated mineralogy, critical assessment. INTRODUCTION In mineral processing, only three approaches aiming at describing froth flotation fundamentally could be considered exhaustive: Pyke’s collision and sliding approach [1], Yoon’s kinetic approach [2] and Schwarz and Koh’s approach [3]. The models will hereafter be referred to as Pyke model, Yoon model and Schwarz and Koh model. The first model makes use of the generalized Sutherland equation collision model, the Dobby-Finch attachment model and its own stability model, the second model considers an extended DLVO approach for the attachment and stability whereas the third model makes use of computational fluid dynamics. All three approaches rely on the widely accepted idea that flotation is a kinetic reaction dependent on a flotation rate constant kp, as expressed in Eq. [4]:"

Jan 1, 2018