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By T. Gong

Often plans to increase plant throughput provide an opportunity for optimising plant equipment and operating methods. This was the case in 2005 at TISCO Jianshan Iron Mine, when an increase in production was planned. The thickening circuit had presented a limitation to the plant throughput and operation with poor overflow clarity and underflow density. Following a course of test work by Outotec, a 53m diameter Supaflo® High Rate Thickener (HRT) was selected for the duty. From early stages of operation of the new thickener, the benefits have been dramatic, including: ? Improved tailings underflow density by 9% ? Improved Overflow clarity to less than 150ppm ? Considerably decreased the water and energy consumption as well as operation cost ? Stable and reliable operation This paper looks at this installation as a case study and compares the previous thickener installa-tion performance with the performance of the single 53m HRT.

Jan 1, 2014

By B. S. Moroney

Elemental distribution varies widely in the ores, minerals and beneficiated products depending on the constituents. Accurate analysis of each element present in various beneficiated products is utmost required to assess the grade in view of zero waste technology. Hence, the suitable methods and instrumental technique is of prime importance as the distribution of various elements differs in the beneficiated products. Conventional classical technique of analysis is absolute and due to this, it has not become obsolete. Besides, it is much needed for making standards for various relative techniques. Instrumental techniques comprising of X-ray fluorescence, Induced Coupled Plasma Analyzer, Carbon-Sulphur Analyzer, Atomic Absorption Spectrometer etc. are important for quick and accurate analysis. However, the selection of these instruments depend on the nature of material to be analyzed. This paper highlights the importance and use of various methods/techniques and instruments involved in the analysis of various ores, minerals and beneficiated products. Keywords: wet classical, x-ray fluorescence, induced coupled plasma analyzer, atomic absorption spectrometer

Sep 1, 2012

By Per Svedensten

One of the most significant behaviour of a crushing plant is the constant variation in the process. The variation is caused by two major effects. The first and constantly changing is the rock material properties. During operation rock material with different strength and particle size distribution is fed to the plant which makes the performance of the equipment to vary. The second and more slowly changing variation is caused by wear on the processing equipment. These effects must be predicted in order to be able to optimise a crushing plant. This paper demonstrates how Monte Carlo simulation can be utilised to study and operate crush-ing plants. By introducing Monte Carlo simulation the varying process can be study and also optimised. To maintain the optimised process performance supervision is needed. This paper demonstrates how results from the Monte Carlo simulation can be utilised for process supervision. Charts for process measurements can for example be derived. These can then be used to guide decision making and understand how the variation and performance of the plant changes over time.

Jan 1, 2014

By F. S. Hoseinian, K. Filho, D. Deglon, T. Souza, M. Safari

"This paper investigates the reverse flotation of hematite in three laboratory flotation cells with very different contacting environments. The main objectives are to investigate the recovery of coarse quartz by flotation and fine hematite by entrainment. The laboratory flotation cells used were the mechanical, oscillating grid and pneumatic cells. The effect of froth height and solid concentration were investigated in the mechanical and pneumatic cells. The effect of impeller speed and energy input were investigated in the mechanical and oscillating grid cells. Froth height results show that coarse quartz particle recovery decreases almost linearly with increasing froth height due to increased detachment of coarse quartz particles in the froth. Fine hematite particle recovery also decreases almost linearly with increasing froth height due to decreased water recovery and associated entrainment. Agitation/energy input results show that coarse quartz particle recovery increases with increasing impeller speed to an optimum, after which this decreases dramatically. The increase is due to improved gas dispersion, generation of smaller bubbles and increased bubble-particle collision and attachment. The decrease is due to significantly increased bubble-particle detachment at higher impeller speeds. The recovery of coarse quartz particles in the OGC is higher than that in the mechanical cell with an optimum at a much lower energy input. Solids concentration results show that both mass recovery and water recovery increase with increasing solid concentrations. The pneumatic cell achieves higher mass recoveries and lower water recoveries than those in the mechanical cell at equivalent solids concentrations and operating conditions. INTRODUCTIONFlotation is a selective process for separating different minerals from each other. The flotation separation efficiency depends on the recoveries of the mineral species by both true flotation and entrainment (Neethling and Cilliers 2009; Wang et al. 2015). Both chemical variables and hydrodynamic conditions within the flotation cell affect the recovery and selectivity of the flotation process. Cationic reverse flotation of hematite is a common method for selective separation of quartz from iron ores to produce pellet feed. The presence of coarse quartz particles in the tailings and fine hematite particles in the concentrate are two major challenges in the reverse flotation of hematite (Vieira and Peres 2007)."

Jan 1, 2018

By Yuri L. Nikolaev

The treatment of placer gold with fine gold, associated with gold-bearing sulfide minerals, heavy minerals and oxidized minerals such as manganowolframite (gubnerite) is not an easy task. In this case, this complex material cannot be treated using physical separation methods such as deep concentration and finishing, magnetic separation and solvent extraction. This technology is usually employed in gold washings finishing plant. The easiest way to recover precious metals in the form of an easy-to-sample saleable product is metallurgical treatment. This paper describes the application of pyrometallurgical processes with oxidative roasting, re-cleaning of cinders (if required) and ore-thermal smelting for producing gold bullion. Hydrometallurgical treatment of slags as an additional operation is recommended in order to maximize recovery of valuable metals. After this treatment, a barren leaching cake rich in PGM can be sold in the market. PGM can be collected as gold-silver alloy during smelting which allows the phase formation of polymetallic matte due to specific composition of fluxes. The PGM are then in the form of saleable gold bullions in the refinery.

Sep 1, 2012

By Marina Nicolova, Irena Spasova, Plamen Georgiev, Stoyan Groudev

Different strains of "silicate" bacteria were used to improve the quality of kaolin by different ways of treatment. All strains formed large slimy capsules consisting of exopolysaccharides and were related to different species of the genus Bacillus, mainly to B. circulans and B. mucilaginosus. It was found that even a short contact of some hours of well developed cultures of these bacteria resulted in improvement of the bending strength and the other ceramic properties of the kaolin. The improvement was connected with the action of some secreted microbial metabolites such as soluble heteropolysccharides, monosugars and organic acids. The best results were achieved by continuous cultivation of bacteria in the presence of kaolin with a high relative humidity and subjected to periodic stirring.

Jan 1, 2014

By Minna Päällysaho

For the first time, the idea of sustainable development was recognised at a high political level at the UN Conference on Environment and Development held in Rio de Janeiro in 1992 (UNEP, 1992). Then the governments of the world committed themselves to promote sustainable development in their national activities and international co-operation. In 2001, the European Council approved the EU Strategy for Sustainable Development (European commission, 2011). This complements and supports the EU?s so-called Lisbon Strategy (European council, 2000) on competitiveness. The revised Strategy for Sustainable Development was approved in June 2006. Recently sustainability has had an important role in policy and decision-making while the public awareness towards limits of the environment has been rising. However, the indicators of industrial sustainability satisfy primarily the needs of corporate management and global investors. The information is often broad and non-specific and might occasionally even give a false impression. Moreover, contradictions between environmental, economical and social aspects also point out the unreliability of existing sustainability indexes. Therefore, the current state of affairs serves the interests of neither the industry nor the policy makers. Current corporate sustainability indexes and indicator systems need to be assessed with scientific methods encompassing the identification of their strengths and weaknesses. This requires quantitative and qualitative assessment and synthesis of existing indexes and indicator systems, providing new data on the functionality of existing corporate sustainability indicators. Therefore, the assessment lays the foundation for the development of new, more balanced sustainability index. Our first aim in this multidisciplinary article is to analyse existing global sustainability indexes for process industry. Second, we will introduce a first version of a new sustainability index for process industry, which includes the environmental, social and economic impacts of the plant, as well as legislation aspects.

Sep 1, 2012

By V. M. Bystritsky, M. G. Sapozhnikov, G. M. Nikitin, A. B. Sadovsky, Yu. N. Rogov

"At present kimberlite ore is processed in crushers or grinding rolls with subsequent grinding in wet mills down to a size of 0.2 mm. The basic disadvantage of the standard diamond processing technology is that crushing kimberlite ore can damage the most valuable large diamonds of few carats. Tagged neutron method offers a possible solution to this problem. It allows detecting diamond inside kimberlite ore without its disruption. The results of the tests of the neutron separator prototype carried out at the Lomonosov processing factory of PJSC Severalmaz are discussed. The possibility to detect the diamond in the rock whose size is 10 times larger than the size of the diamond is demonstrated.INTRODUCTION At present standard diamond processing technology implies disintegration of kimberlite ore in crushers or grinding rolls down to a size of 0.2 mm. It inevitably leads to high probability that large and most valuable diamonds could be damaged. The fraction of diamonds which lost integrity in the process of ore enrichment could be as large as 35-65% [1]. Tagged neutron method (TNM) [2] offers a possible solution to this problem. It allows detecting diamond inside kimberlite ore without its disruption. The main idea of the TNM is irradiation of an object by fast 14.1 MeV neutrons from binary nuclear reaction d + 3H ?4He + n (1) and detecting (tagging) the 4He (a-particle) that accompanies neutron. That gives possibility to determine direction of the neutron momentum. Those tagged neutrons irradiate kimberlite ore under investigation and produce gamma rays via inelastic scattering reactions with nuclei"

Jan 1, 2018

Certainly, one of the core processes for the recovery of fine magnetic susceptible iron ore particles, mainly hematite iron ores, is the wet high intensity magnetic separation or WHIMS. This paper outlines a variety of recent developments and innovative process designs in the JONES® type WHIMS. It highlights the latest examples of flow sheets in terms of the diversity of combined rougher, scavenger, cleaner stages and adds to this the new more advanced JONES® type WHIMS equipment technologies like the HIGH FLOW ? HF, the QUATTRO ? Q and the SPLITT OPERATION ? SP. As a result of the increase of the capacity and magnetic intensity, the specific production cost could be decreased. The high worldwide acceptance for this continuous development testifies for the success and state of the art technology.

Sep 1, 2012

By S. H. Lau

Rapid 3D characterization of multiphase mineral particles in a variety of mineral processing applications is described, including: mineral liberation analysis, grain size, mineral exposure analysis, particle damage, and pore network structure for fluid flow simulation in heap leaching. While micro X-ray computed tomography systems (microCTs) have been used for many years, industrial adoption is limited due to a variety of reasons, including insufficient resolution, the general lack of imaging contrast to differentiate different mineral phases within a multiphase mineral particle and the lack of automated 3D mineral processing software. For example, resolution with industrial CTs and desktop microCT is of the order of tens of microns to a few microns at best, depending on specimen size and CT configuration. We describe a novel lab-based X-ray microscope, XRM, which overcomes these resolution and contrast limitations, notably as the industry is going towards finer grains and more complex ore bodies. Using lens-based optics and detectors (similar to its XRM counterpart in synchrotron beam lines), resolution of the lab based system is in the submicron range with contrast better than conventional microCTs. Hence, visualization, differentiation and segmentation of most mineral phases of interest to the industry are now feasible. Coupling these high resolution and high contrast tomography images with a suite of customized 3D segmentation algorithms and analysis software, applications in mineral liberation analysis for process control, particle damage assessment and other mineral processing applications can be achieved. This non invasive 3D technique which requires relatively little sample preparation is currently being considered for coal, industrial minerals, and base/precious metal ores, complementing existing microscopy techniques such as QEMSCAN and MLA for a variety of applications

Sep 1, 2012

By M. R. Garmsiri

With the environmental issues and water recycling becoming more significant, the development of deep cone thickeners has improved the efficiency of thickening. While deep cones performance is dependent on many factors, the sensitivity of an industrial thickener to each variable factor has not been determined. In this work, four industrial deep cone thickeners, which are used on tailings stream in Shahrebabak Copper Complex, were monitored for a year to analyze the effectiveness of different factors affecting the performance. Feed flow rate, fine fraction of the feed, solids concentration, flocculant dosage and concentration, solids density, pH, temperature and bed height were the factors investigated on the basis of partial R2 and partial correlation. Results indicated that, with positive effect, feed slurry dilution affected the dewatering efficiency most sensitively. With a negative effect, the sensitivity of dewatering efficiency of deep cone thickeners to flocculant dosage was negligible. While, decreasing flocculant solution concentration had a considerable positive effect.

Sep 1, 2012

By P. Matias

The study involved two projects that will produce copper concentrate and may have their operations integrated. Transport by trucks, conveyor belt, and the equipment called RopeCon were evaluated as options for the ore transport between the sites. A rainforest stretch, that Vale S.A. demands to preserve, is situated between the projects. It was suggested to further review RopeCon because it presents minimal interactions with the environment. To design the preliminary system layout, a research was done on the rainforest cover height data, but the information found was scarce and imprecise. For preserving the local forest, the use of this data would conduct to the oversizing of RopeCon towers and, consequently, overestimation of its costs. For the acquisition of reliable information, a method was developed using local data acquired through airborne laser survey. The volume between the digital surface and terrain models was calculated to generate a surface representing the forest cover height. It was revealed, by plotting the points obtained from this surface, that 85% of the vegetation is below 25 m. This height is suggested to review the preliminary project with a more accurate design of the equipment towers, thus reducing its costs estimates. The method permits the precise location of the large trees, making easier to find a pathway, for linear-shaped facilities, that would minimize the creation of vegetation-free zones as a measure to protect equipments against falling trees and forest fires. Keywords: forest cover, mining projects facilities, digital models, airborne laser survey

Sep 1, 2012

By Cristian Melipichun, Leopoldo Gutierrez

The effect of the presence of fine particles of kaolinite and montmorillonite on the induction time for attachment of bubbles to particles of a copper concentrate rich in chalcopyrite was evaluated in this study. The results obtained from induction time measurements were correlated with data of concentrate recovery achieved from micro-flotation experiments. The effect of the presence of fine clays on the stability of air-water foams was also studied through measurements of the foam volume generated in a glass column under different conditions of air flowrate and MIBC concentrations. The experimental results showed that induction time values increased under the presence of fine clays. These data agreed with results obtained from micro-flotation experiments that showed that copper concentrate recovery decreased when clay particles were added. Although a complete explanation for these results is not available, the fact that experimental observations indicated that fine clay particles tend to adsorb on gas bubbles, suggests that the interactions between fine phyllosilicate particles and air bubbles have to be taken into account when studying the effect of clays on froth flotation. Foamability tests showed that the presence of fine clay particles increased the foam volumes only at high additions of clays and low dosages of MIBC. The results obtained at higher dosages of MIBC showed that the foam volumes decreased with the addition of clays under all the experimental conditions tested.

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 B. McFadzean, K. Moller

"The mechanism whereby thiol collectors adsorb onto a mineral surface has been widely studied. Most of these studies examine the mineral surface at equilibrium state and, often, well above monolayer coverage. However, the formation of species at the mineral surface is a complex process that is both kinetically and thermodynamically controlled. In a typical industrial application, the dosage of collector will be around monolayer level. This study uses isothermal titration microcalorimetry to measure the heat evolved during the reaction of sodium ethyl xanthate (SEX) and sodium isobutyl dithiocarbamate (SIBDTC) and their mixtures with galena and chalcopyrite. The sensitivity of the instrument allows heats of reaction of sub-monolayer quantities of thiol collector to be measured.The study found that both the magnitude and kinetics of the reaction between a collector and a mineral surface was dependent on the type of mineral and the type of collector. Proposals are made for the reactions based on literature and the evidence from this investigation. It was found that when collectors were reacted with mixtures of galena and chalcopyrite, that the magnitude of the reaction was lower compared to that measured for the pure minerals alone. This may be due to galvanic interactions between the minerals, resulting in a passivating effect on one or both of the minerals."

Jan 1, 2014

By M. Brennan, A. Majumder

"The mineral processing research community has devoted enormous efforts to the modelling of mineral separators over the last 50 years. While many efforts have been made to use only fundamental physics as a basis for the models, fluid flow patterns in separators are not simple while the motion of particle swarms through fluids is extremely complex.One of the simplest separators is the sluice, in which separation takes place in a flowing film a few millimetres thick. The particles are suspended by turbulent eddies and motion relative to the fluid takes place in so-called hindered settling mode.In an effort to test the extent to which fundamental fluid mechanics can provide a prediction of particle separation, a study on a simple parallel-sided sluice has been carried out using glass beads at various particle concentrations and flow rates.The actual particle separation taking place was compared to predictions made by first describing the fluid flow by a modified ‘law of the wall’ model.Particle concentration distributions were described using Hunt’s sediment transport model, assuming the particle eddy diffusion coefficient to be the same as that for the water. Settling velocities were calculated using either the Richardson and Zaki or Brauer and Thiele models. The latter takes into account particle size and density distributions and solids volumetric concentration.The resulting predictions of particle separation are remarkably good, even though the model does not model the local settling velocity in the slurry."

Jan 1, 2003

By Érica Linhares, Anderson Silveira Lopes, Aline Costa

In the production units of ferromanganese alloys wastewater are generated. They mainly arise from gutters of drainage water from warehouse of raw material (manganese ore, reducing agents and other), product and slag. This wastewater, in general, may contain particles that will suffer difficulty to naturally decant, giving the water turbidity and color characteristics. Thus, this study aims to characterize the effluent, the treated water and the sludge from the sedimentation tank from the one main Brazilian plant. The investigated characteristics were: turbidity, total solids (TS), suspended solids (SS), dissolved solids (DS), pH, Eh, COD (chemical oxygen demand), residue classification and chemical analysis by ICP - OES. The turbidity before treatment was 417 NTU and after passing through the tank, 44 NTU, a figure slightly higher than the emission standards for Class 1 regulated by the Brazilian environmental legislation in force. The values for TS, SS and DS of the effluent were 225, 114.3 and 110 mg/L, respectively. For the treated water the values were 93, 48.3 and 45 mg/L for TS, SS and DS, respectively. The sedimentation process was able to reduce by 21 % of the COD. In the test of loss on ignition (LOI) from the tank bottom sludge were observed losses of 29.35 %, while the volatile analysis found 20.70 % of volatiles in the sample. It was determined that the concentrations of Al, Fe, Mn and S are, respectively, 0.1875 mg.L-1, 0.3071 mg.L-1, 0,789 mg l-1 and 0.00828 mg.L-1, values above the maximum allowed by law. Based on the analysis of X-ray diffraction, the identified minerals in the sludge were quartz, muscovite, kaolinite, calcite and albite.

Jan 1, 2014

By Fatemeh Saeidi, Malcolm S. Powell, Mohsen Yahyaei

In order to deal with the problems of existing comminution models a new approach towards the development of mechanistic models has been made so as to better understand the physics of milling processes and environments. Despite enormous improvement in this field a comprehensive study of rock breakage characterisation, appropriate for use in these types of models, is still scarce. This paper reviews the existing models of comminution according to ore characterisation techniques and parameters. The authors have looked into the existing testing methods and their applied mechanisms of breakage, using standard test results available at the JKMRC. The study includes classifying testing devices such as the drop weight tester, rotary breakage tester, slow compression, and piston and die based on the few major fundamental mechanisms of breakage that are experienced by rocks in the breakage process. The paper compares the range of particle size and energy utilisation, applied strain rates and loading mechanisms for the equipment. The product size distributions from the various equipment is compared for equivalent input energies, various loading rates but the same level of energy intensity, a broad range of energy including low energy utilisation and fines generation rate for equivalent specific energy input. The results clearly show that the outcomes and conclusions on competence and energy for breakage are a function of the test method that is applied. In ongoing work, it is proposed to investigate common tests that can be applied to characterising ores in a manner suited to modelling a range of comminution devices.

Jan 1, 2014

By X. L. Song

In this paper, ZrSiO4-Cd(S1-xSex) inclusion pigments were synthesized by hydrothermal method. Microstructure, morphology and properties of the powder were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared spectroscopy (IR) and CIE chromaticity, respectively. It shows that, precursors obtained at pH is about 6.0 are sol and products with higher crystallinity, red hues (a*=38.23) and inclusion ratio when hydrothermal synthesis temperature is 180? and holding time is 12h. Hydrothermal reaction mechanism was further analyzed as well. In particular, an ideal model of pigment formation was proposed.

Jan 1, 2014

By Janne Kauppi, Kaj Jansson, Piia Suvio, Saara Hagnäs

"Historically the focus at the mineral processing sites has been to improve the production operations, while little focus has been set on how factors, such as the quality of water used in the process affects the metal recovery. Simultaneously increasing public pressure and water scarcity is driving the mining industry to recycle more water back to the process, which in turn leads to accumulation of impurities within the recycled water. This paper presents a concept for a systematic approach on targeting the impurities that have a negative effect on the metal recovery at the flotation circuit by using a novel solution called Process Water Recycling Plant (PWRP). These plants are designed with specific ore type in mind. PWRP produces cost-effectively process water to different target qualities, especially for flotation purposes enabling higher and more stable flotation recovery. It consists of pre-designed and standard water treatment units for a wide range of volumes. The application-specific configuration of units is governed by the water quality requirements, and can be designed according to specific customer needs. Testing has been carried out in order to investigate, which recycling water impurities affect the different ore types and how the metal recovery in flotation is affected as a consequence of the poor-quality water. The results indicate that every ore type is impacted differently and without a good understanding on how the water quality impacts the process performance, adverse effects on the flotation recovery can occur.INTRODUCTION With a focus on where water is used within the mineral processing, it has become evident that even though water is used in several different processes, majority of the water losses within the site occur at the tailings processing and the tailings storage facility. New tailings management technologies that can increase the recovery of water are actively being developed, but the key to improving the efficiency of water use and reducing the operational risks lies in closing the water loops and increasing the slurry density in the tailings processing. With this shift from conventional tailings technologies towards paste and dry stacking, water efficiency is vastly improved, but it might in turn lead to process water challenges with impurities, reagents and fines being recycled and accumulated within the production processes."

Jan 1, 2018