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By S. M. Viduka

This paper presents a numerical investigation of solid separation in jigging device, which is a gravity separation method widely used in ore processing. Separation is recognized as being heavily dependent on fluid motion in the jig. This study explores the effects of the inlet time dependent velocity profile on jigging performance. Modelling of the liquid-solid system is performed through a combination of computational fluid dynamics (CFD) to simulate liquid flow and discrete element method (DEM) to resolve particle motion. The initial packing conditions consist of a binary-density particle system of 1130 particles each 1 cm in diameter. A variety of jigging profiles are implemented in jigging. The saw tooth pulsation profile is selected with three variations in both amplitude and frequency. The performance of each profile variant is compared in terms of solid flow patterns, separation kinetics, energy, and mean particle position. These quantitative comparisons demonstrate significant differences in the segregation rate, energy, and solid phenomena, helping find an alternative optimum operating setting for the system.

Sep 1, 2012

By E. V. Bratygin, E. G. Dmitrieva

The aim of the research was to study the thermodynamic characteristics of high-temperature processing of ilmenite concentrate deposits "Central" in a neutral and oxidizing atmosphere, as well as its interaction with alkaline additives. The research was conducted using a scanning colonoscopy on thermogravimetrical analyzer NETZSCH STA 449 F3. A sample of the test material weighing 10 mg was placed in a crucible and heated at a rate of 10 °C/min to 1200 °C in argon or air. Studies have been conducted pure ilmenite concentrate and its mixtures with 5 % and 12.5% of sodium carbonate. The results of the analysis of the thermogravimetric curves it was found that the recovery of the concentrate carbon will come from ulvospinel, not pseudobrookite, and the reaction recovery is possible at temperatures above 900°C. While removing produced in the decay ilmenorutile of iron oxides in an inactive form, for example, iron (III) oxide, it is possible to reduce the quantity of the solution of ilmenite formed during the restoration of the melt anosovite. The analysis of data obtained during heating of ilmenite concentrate with sodium carbonate in concentrations of 5 and 12.5% transition pseudobrookite in ulvospinel is missing, it just breaks down into hematite and titanium oxide, which, in turn, react with N?2??3. It should be noted that increasing the concentration of sodium carbonate in the sample contributes to more complete interaction of iron oxides and N?2??3 with formation of ferrites of sodium. This can ensure full recovery of iron oxides in the concentrate, which is part of secondary ilmenite can not be dissolved in the melt formed by the lower oxides of titanium. In addition, the increase in the content of soda in the mixture significantly reduces the temperature of the initial melting point of the slag and facilitates the coagulation of metallic iron.The obtained results were used for laboratory studies of the solid-phase sintering of briquettes from ilmenite concentrate with additives of sodium carbonate and a reducing – coal, as well as for the development of technological mode of solid-phase sintering of the concentrate with the aim of obtaining product recovery with a titanium dioxide content of more than 75 %.

Jan 1, 2018

By Y. Y. Li, T. T. Yang, R. X. Zhou, Z. H. Shen

"Wetting theory is one of the basic theories of flotation. The effects of concentrations, carbon chain length and pH values of saturated fatty acid collectors (lauric acid, myristic acid, palmitic acid and stearic acid) on the surface wettability of collophanite and dolomite were investigated by measuring the contact angle with dynamic captive-bubble technique and calculating adhesion work of bubble-mineral. The results show that the contact angles both of collophanite and dolomite are higher with enhancement of hydrophobicity when pH value of 5~9. The contact angles both of collophanite and dolomite are reduced with improvement of surface hydrophilicity. When strong acid pH value of 2~4 or strong alkaline pH value of 10~13. The reasons for this are that the fatty acids mainly exist with insoluble RCOOH molecules in strong acid condition, and competitive adsorption of OH- and RCOO- in the mineral surface is formed in strong alkaline condition. With the increase of the collector concentration, the contact angles of the collophanite and the dolomite all first increase then decrease. The formation of hydrophilic micelles results in the decreasing of contact angles and enhancement of surface hydrophilicity opposite when the collector concentration exceeds CMC. The contact angles of the collophanite and dolomite and the WSG of the bubble adhesion increase, the hydrophobicity enhance with the increasing of carbon chains of saturated fatty acid from 12 to 18. The variation tendency for the adsorption quantity of collectors and floatability of collophanite and dolomite are in line with the change trend of contact angle basically. It shows that the wettability of solid-liquid-gas interface can be well characterized by the dynamic captive-bubble technique.INTRODUCTIONPhosphorite resources are the main raw material for producing phosphate fertilizer and producing phosphoric acid (Cao et al.,2005), which is an important strategic mineral resource. The useful minerals in calcareous-magnesium phosphate ore are collophanite, and the main gangue minerals are dolomite (SISH et al.,2003). The lattice ions of the phosphorite and dolomite are both Ca2+, their similar surface properties and similar floatability are the main reason for the flotation of calcareous-magnesium phosphate ore difficultly (Fang et al.,2011). Usually, fatty acid collectors are used for the flotation of calcareous-magnesium phosphate ore under acidic conditions by reversing flotation method to remove dolomite (ABOUZEID et al.,2009), or direct flotation is used to gather collophanite in the alkaline conditions (Gong et al.,2017). The flotation behavior of collophanite and dolomite affects the indexes of concentrate and flotation efficiency directly. Therefore, it is necessary to study the action mechanism and the flotation method of the collector with the phosphate rock and dolomite respectively (Moudgil et al.,1988; Hanna, et al.,1990)."

Jan 1, 2018

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 Heikki Häkkänen, Tommi Kauppinen, Navid Khajehzadeh

"There are a variety of methods suitable to analyse elemental and mineralogical contents of rock drill core samples. Current demands are on fast exploration and objective analysis of ore samples. This paper proposes a combination of Laser-Induced Fluorescence (LIF) and image processing, entitled LIF-imaging, as a potential method for automated mineral analysis of the drill core samples. It is shown that LIF-imaging can produce a mineral map of the fluorescent minerals existing on the surface of the drill core samples. The test cases are drill core samples from a Ni-Cu mine situated in Kevitsa, Finland. The main prerequisite of LIF-imaging technique is a reference data, linking colours to the minerals. This study describes the calibration of LIF-imaging technique using precise but slow Raman spectroscopy. Using regularized logistic regression, a model is obtained that classifies the minerals based on their emitted fluorescent colours in the digital images. The abundance of each mineral group is estimated by pixel counting. The results are compared with X-Ray Diffraction laboratory assays performed on the same samples. The results show that the interpretation of the fluorescent minerals through LIF images corresponds to the XRD results. Furthermore, the utilization of the logistic regression to interpret the existing fluorescent minerals greatly improves the technique."

Jan 1, 2014

By Zhangm Zeqiang, Manman Lu, Hanquan Zhang, Hong Yu, Jintao Fu

"Pelletizing is an important technique in the ironmaking industry. Artificial and natural magnetites are materials that are widely utilized in the iron ore pelletizing process. In this work, the pelletizing characteristics of these two types of magnetite have been investigated in detail. The obtained results shown that in contrast to natural magnetite, the artificial magnetite concentrate exhibits stronger hydrophilicity, lower electronegativity, larger specific surface area, and rougher surface. In addition, the green pellets produced from the artificial magnetite concentrate are characterized by a higher compressive strength as compared to that of the pellets obtained from the natural magnetite concentrate. However, the shock temperature of the artificial magnetite pellets around 255 C is significantly lower than the threshold specified by the industry. The balling characteristics of the material obtained by mixing 20% of the artificial magnetite concentrate with 80% of the natural magnetite concentrate are considerably improved with respect to those of the individual components.INTRODUCTION Pelletization is an essential process of the ironmaking industry in China. Since the pellets produced from iron ore exhibit high mechanical strength, good particle granularity, and uniform shapes, pelletizing high-grade iron ores with good metallurgical reducibility can lower the coke ratio, improve their technico-economic index, and reduce the cost of processing pig iron in blast furnaces[1, 2]. Presently, high-grade magnetite is a material utilized for pelletizing various iron ores across the globe. However, its natural deposits have been depleting rapidly in recent years; as a result[3], China’s dependence on the foreign high-grade iron ores exceeded 70% in 2009 and reached the level of 87% in 2016. Hence, possible methods for the efficient cultivation of limonite, siderite, hematite, and other refractory minerals that correspond to low-grade, finely sized, inhomogeneous, and scattered iron ores have attracted significant attention [4, 5]. In particular, magnetization reduction roasting and magnetic separation techniques, which are widely utilized for obtaining high-grade artificial magnetite, represent effective ways of processing iron ores that can alleviate the scarcity of natural magnetite resources [6, 7]. The artificial magnetite produced by magnetization reduction roasting exhibits different characteristics as compared with those of natural magnetite (including the degree of hydrophilicity, surface potential, specific surface area, and other surface physicochemical properties[8-11], which significantly affect its pelletizing behavior. In this work, the surface characteristics of artificial and natural magnetites are investigated in detail, and their effect on their pelletizing properties (such as green ball strength, heat stability, and pelletization rate) are examined."

Jan 1, 2018

High flotation of iron sulfide minerals at high pH values in copper ores is mainly due to the activation of these minerals by copper species dissolved from copper sulfide minerals during grinding. Several methods have been tested to reduce this copper activation during grinding and therefore to depress iron sulfide flotation. They include grinding the minerals at high pH values or with a less reactive medium such as high chrome, and addition of a thiol collector or copper complexant during grinding. The efficacy of these methods in the flotation of a copper ore was tested against more common methods of depression of iron sulfide flotation. The mechanism of iron sulfide depression in these methods was also investigated.

Jan 1, 2014

By Gaurav Soni, Roe-Hoan Yoon

A first principle flotation model has been derived from the basic mechanisms involved in flotation. The model consists of a series of analytical equations for bubble generation, bubble-particle collision, attachment, detachment, and froth phase recovery. The model can predict flotation from both hydrodynamic and surface chemistry parameters such as bubble size, particle size, energy dissipation rate, ?-potentials, contact angles (?), etc. The model predictions have been compared with the results of a series of laboratory flotation tests conducted using mono-sized glass beads of different particle sizes and contact angles under different operating conditions. Some of the experiments were conducted using a 1:9 mixtures if hydrophobic silica and hydrophilic magnetite, so that the product graded could be readily determined by simple magnetic separation. The model predictions are in good agreement with the experimental results both in recovery and grade. A computer simulator developed on the basis of the model is capable of designing a preliminary flotation circuit on the basis of feed characteristics, e.g., size-by-liberation data, and the hydrodynamic information on the flotation cells to be incorporated in the circuit.

Jan 1, 2014

By Masanori Mori, Hajime Miki, Osamu Ichikawa, Tsuyoshi Hirajima, Mitsuru Sawada, Keiko Sasaki

For pretreatment of selective flotation, surface oxidation of chalcopyrite and molybdenite was applied by oxygen plasma then the minerals were washed by solution at pH 9 with oxygen bubbling. Surface characteristics of these minerals were investigated with AFM, XPS, zeta potential and contact angle measurements. Contact angle of chalcopyrite and molybdenite decreased a lot by plasma treatment. When they were washed with pH 9 solution with oxygen bubbling, contact angle of molybdenite increased whereas chalcopyrite one kept low. Adhesion force measurements indicated similar behavior. Result of flotation experiments indicated low recovery of both chalcopyrite and molybdenite after plasma treatment and only molybdenite recovery became higher after washing. Selective flotation of chalcopyrite and molybdenite could be achieved with this process. Possible mechanism of selective flotation was proposed from the results of XPS, AFM, etc.

Jan 1, 2014

By Shuji Owada, Shinya Suzuki, Chiharu Tokoro, Daisuke Haraguchi, Sayaka Izawa

"Coprecipitation with ferrihydrite has been one of the major treatment method for As(V) removal from wastewater such as acid mine drainage. We already confirmed coprecipitation of As(V) with ferrihydrite consists of two kinds of mechanism; one is two dimensional As(V) uptake to the surface of ferrihydrite by surface complexation and another is three dimensional As(V) uptake into ferrihydrite by surface precipitation. We also already confirmed As(V) adsorption process by ferrihydrite could be quantitatively evaluated by original surface complexation model with parameter values reported by Dzombak and Morel. However, As(V) coprecipitation process couldn’t quantitatively be represented by only the original model. In this study, construction and calculation using surface precipitation model were attempted for As(V) coprecipitation treatment with ferrihydrite. In the surface precipitation model, precipitation was described by the formation of solid compound between ferrihydrite and ferric arsenate. Activity of these precipitates was determined by surface precipitation ratio of FeAsO4(s) obtained experimentally from XANES analyses. Solubility products of surface precipitation of FeAsO4(s) (Ksp_FeAsO4(suf.)) were determined by fitting to sorption densities and surface precipitation ratio in each condition. The values of Ksp_FeAsO4(suf.) were determined 10-7.7 at pH5 and 10-10.2 at pH7, respectively. Based on the obtained Ksp_FeAsO4(suf.) value, As(V) removal and isotherm were calculated for As(V) co-precipitation treatment using surface precipitation model. Good agreement between experimental and calculated values was observed. These results were suggested that the quantitative prediction of As(V) co-precipitation treatment was possible if Ksp_FeAsO4(suf.) value was estimated experimentally."

Jan 1, 2014

By P. Vijay Kumar

Phosphate minerals are conventionally concentrated by flotation process using soap or soap- light diesel oil emulsion as collector. Some plants use detergents such as sodium petroleum sulfonate or alfa olefin sulfonate to enhance efficiency of soap flotation. It is reported that urea a known hydrotrope enhances flotation efficiency of soap as efficiently as alfa olefin sulfonate or linear alkyl benzene sulfonate at bench scale tests. In the present study tri sodium citrate also a known hydrotrope is tested as promoter in the flotation of phosphate mineral from Eshidiya ore.

Sep 1, 2012

By Jacob Masliyah, Zhenghe Xu, Lujie Yan

"Understanding adsorption mechanism of polymeric organic process modifierssuch as carboxymethyl cellulose (CMC) on talc hasbeen a major challenge due to anisotropic nature of talc basal planes and edge surfaces. The main objective of this study is to investigate the adsorption of CMC on the basal planes and edge surfaces of talc.Smooth basal plane and edge surfaces of talc were prepared successfully by simple cleavage and sophisticated ultramicrotome cutting method, respectively. The prepared surfaces were characterized by atomic force microscope (AFM) imaging to be sufficiently smooth for colloidal probe force measurements using AFM. Anisotropic surface charge characteristics were determined,with the basal planes to carry a permanent negative surface charge and edge surfaces featuring a pH-dependent charge characteristic. The adsorption of CMC on talc basal plane and edge surfaces at pH 9 in KClaqueous solutions of various ionic strengths wasinvestigated by in situ AFM imaging technique. Themorphology of adsorbed CMC on talc basal planes and edge surfaces was found to be significantly different, due to different binding mechanisms involved. Interaction of CMC with the talc basal plane was found to bedominated by hydrophobic interactions while its binding with the talc edge surface was mainly through chemical complexation and hydrogen bond. The amount of CMC adsorbed on both talc basal planes and edge surfaces increased with increasing ionic strengthof solutions. The methodology developed in our study opens the door to probe polymer adsorption on anisotropic phyllosilicate surfaces, which can help us better understand the mechanism of polymer adsorption on specific mineral faces."

Jan 1, 2014

By G. S. Zeng

The mechanism of cobalt removal from zinc sulfate solution with zinc dust is still not understood well. The experiments in this paper were carried out by zinc dust from zinc sulfate solution with high cobalt to study the mechanism of cobalt removal. Residues after the cementation process from zinc sulfate solution were analyzed by SEM and Electron probe micro-analysis (EPMA) to investigate the morphology of products. Different temperature will cause different structure of particles. With the increasement of temperature, cobalt removal can be improved considerably. The mechanism of cobalt removal by zinc dust is thought as follows: firstly, the cobalt ion forms Co-Zn alloy with zinc particles, and the reaction reaches equilibrium quickly; secondly, the Co-Zn alloy continues reacting to Co with Co2+, which is the control procedure of the whole reaction.

Jan 1, 2014

By F. L. Wang

The purification process of water-mining carnallite and rough potassium chloride concentrate from Qinghai Salt Lake Industry Group Co. Ltd. are investigated by the preprocessing-reverse flotation technology respectively. The results show that the impurities such as calcium sulfate and sodium chloride can be effectively removed from water-mining carnallite ore and rough potassium chloride concentrate by the new technology, the low-sodium carnallite is obtained and the final potassium chloride product greatly upgraded. The content and the recovery of KCl in the low-sodium carnallite are 25.78% and 97.50%, meanwhile the content of NaCl, CaSO4 in the low-sodium carnallite are 0.56% and 0.24%, and the removal of sodium chloride and calcium sulfate in the low-sodium carnallite are 97.48%, 85.10% respectively. The KCl content and recovery of high quality potassium chloride product are 98.25%, 96.70%, and CaSO4 content is 0.40% with 83.24% calcium sulfate removed in the high quality potassium chloride product.

Jan 1, 2014

By K. Haga

In this study, flotation tests were performed to investigate behavior of enargite and chalcopyrite ores from different sources synthetically mixed for separation of enargite. Flotation parameters including; pH, reagents concentration and type and flotation time were controlled to obtain an enargite concentrate with high As and chalcopyrite concentrate and final tailings with As content below 0.5 mass%. The copper ore bearing enargite mineral contained 5.87 mass% As and 16.50 mass% Cu while the chalcopyrite bearing ore contained 0.32 mass% As and 21.63 mass% Cu. The two ore samples were mixed at 7:3 (enargite: chalcopyrite) by weight ratio to prepare a mixed ore sample with arsenic content at 3.16 mass% and 18.25 mass% Cu for the flotation study. For enargite single ore flotation, the 38?75 µm size fraction showed that over 98% enargite was selectively recovered within 5 min at slurry pH of 4.0 and arsenic content in the final tailings was reduced to 0.22 mass%. In mix ore (enargite+chalcopyrite) flotation, 97% of enargite was first removed at pH 4 followed by chalcopyrite flotation at pH 8, and over 95% recovery was achieved in 15 min flotation time. Arsenic content in the final tailings was reduced to 0.1 mass%.

Sep 1, 2012

By X. Q. Ma

The beneficiation test on low grade phosphate ore from a state of Russia is carried out. The rougher-cleaner ? re-cleaner system is used in the flotation process, The fineness of grind is 39.07% minus 200 mesh. The result indicates that concentrate containing 31.25% P2O5 can be obtained from the flotation feed assaying 6.18% P2O5, with 93.54% P2O5 recovery. The test result is also a guideline for further development of some currently operated phosphate beneficiation plants.

Jan 1, 2014

By Lawrence Bbosa, Aubrey Mainza, Indresan Govender

"Positron Emission Particle Tracking (PEPT) and the Discrete Element Method (DEM) are used to develop a probability based model for the power draw of a tumbling mill. Experiments are conducted using dry spherical glass bead charge in a laboratory scale tumbling mill, which is mounted with a torque transducer and tachometer to measure mill power. Particle tracking information from PEPT is used to reconstruct the motion of glass beads and infer the overall charge behavior, while DEM is employed to simulate particle motion and interaction, with collision mechanics calculated using the Hertz-Mindlin contact model. For both sets of data, the product of torque and average angular velocities in discrete cells are accumulated to obtain mill power. This method is found to be within statistical agreement with measured power for all tests. The information from both techniques is then used to develop a model for the power draw as a function of particle size, mill speed and volumetric filling. Predictions of the model match well with measured and calculated values. The model is found to predict mill power within close agreement with measurement and follows trends consistent with existing work on tumbling mill modelling."

Jan 1, 2014

By Dingwu Feng, Jannie S. J. van Devente

"The effect of ultrasonication on reactions at solid/liquid interfaces was investigated in two slurry systems, i.e. gold cyanidation and geopolymerisation. The kinetics of gold extraction were significantly enhanced and the cyanide consumption was reduced in the cyanidation of a pyrite concentrate using ultrasonication, probably due to the prevention of leaching passivation, the improvement of the dissolution of the gold host sulphides and the oxidation of soluble sulphides to sulphate. The effectiveness for ultrasonication was improved with the injection of oxygen and the addition of dithiophosphate through enhancing the formation of the oxidation radicals and selectively inducing cavitation bubbles directly at the sulphide interfaces. Ultrasonically enhanced cyanidation could render currently uneconomic deposits viable for extraction by improved cavitation efficiency with the aid of surfactants.Ultrasonication increased the compressive strength of the formed geopolymers through accelerating the dissolution of the Al-Si materials, strengthening the bonds at the solid particle/gel phase interfaces, enhancing the polycondensation process and improving the formation of semi-crystalline to crystalline phases. The use of power ultrasound will yield high-performance geopolymer materials."

Jan 1, 2003

By M. Rudolph, E. Schach, M. Buchmann, T. Leißner, N. Krupko, U. Peuker, M. Kern

"In mineral processing, density and magnetic susceptibility are two very fundamental properties. For the beneficiation of valuables to produce a saleable concentrate a detailed understanding of these properties is essential. Especially when it comes to the processing of cassiterite, which is the main mineral for tin production, they become highly prominent. Due to the chemically inert character of cassiterite towards most industrial applied leaching agents, density and magnetic separation processes are mainly applied for its beneficiation. To guarantee an optimized utilization of the different operations not only cassiterite but also the different gangue minerals have to be considered. In this study, a skarn ore is characterized by density and magnetic susceptibility. Therefore, the material was first split into different density classes by heavy liquid separation. The obtained classes were further separated by their susceptibility to finally obtain a density-susceptibility matrix. For this purpose, an isodynamic separator was used. A more detailed characterization of the materials is done via gas pycnometer, magnetic susceptibility balance and vibrating sample magnetometer to estimate the characteristics of density and susceptibility for the various classes. Further, the determination of the chemical assay and the mineral intergrowth by mineral liberation analysis is used to generate a three dimensional database for detailed characterization of the present ore. The objective of this study is to estimate potential material streams for a modular processing plant via characterization of the material for the entire deposit by the two afore mentioned characteristic properties. The established multidimensional data matrix, enables predictions for the separation properties of the material and contributes to the characterization of the deposit within the context of geometallurgy."

Jan 1, 2018

By Rob Morrison, Andrew Scott

"Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data - especially with semi-automated data acquisition by instrumented mine equipment.However, much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model.An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc, not only have many areas of interest but also have very different conceptual models by which they evaluate performance.It is too ambitious to attempt to bring all of these cultures together - in a single step.However, the success of the Mine to Mill - project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measurement and then to track performance from ore body model to saleable product and waste disposal. From resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling.However, in both cases the data collected is strongly focused on the technical requirements - not on the business model.This paper considers how to define at least some of the key decision points in terms of some case studies.Performance data from many areas might be used to derive simple models which can then be used for forecasting and optimisation of planning."

Jan 1, 2003