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By Johan Nell, Paul den Hoed

"Carbochlorination tests were conducted with matched particle-size fractions of rutile, ilmenite and hightitania slag in a small bubbling fluidized-bed reactor. The effects of temperature, the type and proportion of solid reductant in the charge, and the fraction of Cl2 in the fluidizing gas were investigated. Tests confirm the need for solid carbon in the bed if chlorination is to run at high rates. With solid carbon in the bed, CO supplied with the fluidizing gas does not increase significantly the degree of chlorination after 75 minutes.When large proportions (30 wt%) of carbon are added to the charge, then the reactionTiO2 + 2C + 2Cl2 = TiCl4 + 2COis favoured overTiO2 + C + 2Cl2 = TiCl4 + CO2Ilmenite is chlorinated more quickly than titania slag, which in turn is chlorinated more quickly than rutile. Rates of chlorination at 1100°C and 1000°C are much the same and significantly higher than at 900°C. Chlorination is associated with significant increases in particle porosity (even for rutile), which is brought about by the rapid initial chlorination of FeO and MnO (in ilmenite and slag) and (it is argued) by the chlorination of Ti2O3 which forms at high-energy surface sites."

Jan 1, 2003

By Petrus van Staden, Dragan Milanovic, Francisco Sánchez, Eero Kolehmainen, Carlos Frias

"Currently there is no economical and viable process for on-site metal extraction from Low Grade, Complex or Poly-metallic deposits, and even more, there is not any industrial process or technology able to deal with polymetallic or bulk concentrates containing Cu+Zn+Pb base metals and also precious metals. Traditionally, metals recovery from polymetallic sulfide deposits is performed by mining, selective flotation to separate Cu, Pb and Zn concentrates, and finally, smelting/refining of those concentrates to obtain the refined metals. In many cases, selective flotation of that kind of complex ores produces low metals recovery and low concentrate quality containing impurities such as Hg, As, Bi, etc., which results in high penalties in treatment and refining charges, and consequently, worsening the economy of the mining business. Recovery of the valuable metals from Polymetallic, Complex or Low Grade ores could then be maximised by producing bulk concentrates or middling flotation products to feed novel hydrometallurgical processes, like the integral metallurgical system that is currently under development within the INTMET project. For example, producing bulk concentrates would increase more than 100% Cu+ Zn+Pb cumulative recovery versus conventional selective flotation. Founded by the Horizon-2020 EU Programme, the INTMET Project was started in February 2016 and will be running over three years. The INTMET consortium is led by Cobre Las Cruces (Spain) and integrates twelve partners from seven EU countries, and including Serbia and South Africa as well. The INTMET project represents a challenging opportunity to develop suitable technological solutions to deal efficiently with difficult, polymetallic and complex sulphide ores that are abundant in Europe and worldwide. Main activities carried out during the first 18 months of the INTMET project development includes: (i) An atmospheric leaching pilot plant having a capacity of 300 kg/h bulk concentrate which has been installed and operated continuously for nine months at the Las Cruces mine; (ii) Pressure leaching test work developed by Outotec; (iii) Bioleaching test work performed by Mintek in collaboration with MMI Bor. Prior test work was applied on bulk concentrate samples supplied from Spain, Portugal and Serbia. Some of the results of these technological developments have been very positive and are presented in this paper."

Jan 1, 2018

By Mahdi Shevrini, Hamed Haghi

"In this research, the operation of screen classifying in silica processing circuits was investigated and modified by replacement of available trommel screens with teetered bed separator (TBS). In addition the effect of the mentioned replacement and addition of attrition scrubber on quality of final product, impurities removal, recovery and production rate were inspected. Considering screen efficiency problems to achieve certain particle size distribution, hydraulic classifying system was selected instead of trommel screens. Application of suggested plan improved quality and particle size distribution of produced silica significantly. Optimization of size classification in process circuit resulted in increase in production rate up to 21% (from 67% to 81%), silica recovery (from 68.35% up to 83.11%) and relative enhancement in removal of impurities such as Fe2O3 and TiO2. After optimization and stabilization of grinding and size classification section, industrial attrition scrubbing tests were carried out and the best solid percent and retention time were determined i.e. 70% and 6 minutes, respectively. Using sodium carbonate during attrition scrubbing, has major effect on removal of surface coating and staining especially sharp increase in clay removal; therefore 2 kg/t of sodium carbonate can be optimistic point of industrial procedure for this silica processing plant. It should be mentioned that application of attrition scrubbing which is followed by screw classifier for de-sliming were useful for better cumulating of particles in the range of appropriate liberation degree (+106-300µm) and efficient removal of metallic (iron and titanium oxides) and non-metallic (clays and feldspars) impurities."

Jan 1, 2014

By Marco Le Roux, Quentin Campbell

"Most coal supply contracts include strict limitations on the moisture content of the products. This limitation exists because of calorific, transport cost, and handling reasons. Managing the retention time on product stockpiles to facilitate drainage commonly controls the moisture content in coarser coal products. A large-scale pilot rig has been commissioned to facilitate research in this regard. A stockpile of about 15 tonnes of a typical washed power station feed coal from the South African Witbank coalfield was loaded onto a 6 x 6 m platform on load cells. The platform was shielded from the elements, like rain and wind, and an artificial rain sprinkler system was installed. A variety of rainfall intensities and durations were simulated and the water accumulation and run-off was measured. The material was also sampled for moisture and particle size before and after the series of tests. At the same time, the drainage characteristics of the same coal were determined in smaller scale drainage columns for comparison. Data is presented in this paper on the drainage rates, maximum accumulated moisture, final moisture, and the effect of evaporation. The results showed that for all rainfall patterns tested, drainage ceased after 2 - 3 days, but evaporation continued for at least the time period under investigation, albeit at a low rate. Evaporation contributed to dewatering at rates that depended on wind, temperature and humidity conditions. This caused a slow reduction in moisture content even after the run-off had ceased. The value of the final moisture depended on the coal PSD. It was also found that the intensity and duration of the more intense rainfall events did not significantly affect the maximum water accumulation, with drainage rates equaling the corresponding water addition rates which suggested that water ran off over the surface of the stockpile with limited penetration. During more intense rainfall scenarios, some penetration was apparent."

Jan 1, 2014

By Liang Dianyin

In this paper, the molybdenite flotation tailing of cleaner-scavenger bank which has a mass of very fine particles has been taken as raw ore to be processed by flotation with/without ultrasonic. The effect of ultrasonic frequency, intensity, processing time and uploading location on molybdenite flotation efficiency is investigated by four-factor three-level orthogonal experiment, and the effect significances of these ultrasonic variables to molybdenite flotation efficiency have also been evaluated. Single-factor analysis of variance is conducted to investigate whether the effect of ultrasonic on molybdenum ore flotation efficiency is significant or not. The samples extracted from different ore species in different time have been mixed to analyze the particle size. The results show that the particle size of +38µm in concentrate obviously increases while the particle size of -25µmobviouslydecreaseswith ultrasonic, which means that ultrasonic is good for flotation due to sludge removing effect. Keywords: ultrasonic, flotation efficiency, sulfide ore, tailing, grade, sludge removing

Sep 1, 2012

By Venkataramana Runkana, Pradip Gautham, Beena Rai, Sreedhar Reddy

"IT enabled platforms are the key to provide an integrated view of the business activity or an enterprise as a whole. Attempts to integrate all functions in an enterprise such as mine-to-market initiatives, wherever and to whatever extent implemented, have provided significant benefits to the industry. The transformative potential of IT enabled integration platforms is illustrated in this communication from our own work in this field. TCS PREMAP (Platform for the Realization of Materials and Products) is a knowledge-driven engineering design and development platform which leverages modeling and simulation and artificial intelligence into the engineering design process. We illustrate the customization of this generic platform for the design and optimization of mineral processing plants in an integrated manner. TCS PEACOCK (Process and Equipment Analytics for Optimization and Control) has been developed to enable automation of data analytics in the operating plants. We illustrate its utility and power in improving the plant performance with the help of case studies from our work on pelletization of iron ores and optimization of flotation plants. INTRODUCTION We are living in an exciting digital era. With the advent of cloud computing and social media on the one hand and rapid advances being made in several research areas of interest to us in the minerals and metals industry such as artificial intelligence (AI) & machine learning, robotics, unmanned vehicles including drones, big data analytics, 3D printing, sensor technologies, renewable energies and internet of things (IoT), many disruptive transformations in our industry are on the horizon. Recent advances in information technology (IT) and knowledge engineering, in combination with appropriate domain expertise, that is, our enhanced understanding of the underlying science of mining and mineral processing operations and the availability of a variety of powerful modeling-simulation tools make it possible to address the challenging problems facing the mining and mineral processing industry, in an integrated manner."

Jan 1, 2018

By O. A. Bascur

It is difficult to analyse the economics without an integrated view of mine transactions, stockpile inventories, process flows and assays. The lack of integration of mining and metallurgical information with sufficient detail to analyse and act is a problem. However, to take action requires real time information from manufacturing assets, corrected for gross errors from trucks, shovels, conveyors, faulty sensors, bad instrument calibration. Validation methods use process models to identify inconsistent information in the case of corrupt actionable information. This paper presents new strategies that transform the data into business information for continuous improvement and optimization. This technical presentation will review recent implementations enabling large metallurgical complexes to improve their data quality for overall production and energy management. A competence center emerges as an enabler for implementing operational intelligence. The evolution of Web services to troubleshoot plant information and to collaborate at the enterprise level is presented.

Jan 1, 2014

By A. Y. Senchenko, Y. V. Kulikov

"The most common technique for selection of grinding equipment is the Bond method implying determination of a ball mill work index (BWi). The method is perfect for greenfield projects where a ball mill must be sized to grind an ore to 80% passing 75-100 µm. Finer grinding will require application of specific correction factors to a standard equation since initially the method was not designated for sizing of fine (minus 75 µm) grinding mills. Significant issues are related to selection of grinding equipment for treatment of originally fine materials when the standard procedure is not applicable. In 1984, Levin published his special technique titled as “A proposed test for the determination of the grindability of fine materials”, where he offered to use the standard Bond ball mill for determination of a specific grinding energy. However, this method did not meet with wide recognition. In 2017, Institute TOMS under guidance of JKMRC’s specialists performed a testwork aimed at verification of a new universal technique for determination of grindability of initially fine materials. An object was to test three aged tailings samples for the subsequent modelling of comminution circuit and evaluation of potential throughput of the existing ball mills with final grind size of ?80 passing 53 µm. In parallel with development of the universal approach, TOMS’ specialists carried out tests according to the Levin method in order to compare the data resulted from two methods. The results from lab ball mill testing on three products following the alternative test methods are presented in this paper along with the testing methodology and results analysis. Specific energy was calculated for regrinding of the materials to the required size. Difference of the examined methods and assessment of their applicability for sizing of full-scale equipment are explored."

Jan 1, 2018

By Y. S. Sun, P. Gao

Compared with conventional roasting and magnetic separation processes, higher reduction temperatures and stronger reducing atmospheres are used in reduction technologies to reduce iron oxides to metallic iron, which is often liberated during reduction and amenable to magnetic separation. Reduction and magnetic separation of an Australian refractory iron ore was therefore studied as a function of reduction temperature, time, coal addition, feed thickness and size of Australia iron ore. It was found that during reduction, the particle size of the reduced iron increased with reduction temperature and time. Subsequent magnetic separation tests were further conducted on the reduction products. A reduced iron powder with a Fe grade of 85.67% was obtained at a Fe recovery of 87.82% under optimum reduction conditions where a metallization rate of 85.82% was achieved. The mechanism involved in reduction is discussed based on XRD and SEM examinations. And the results indicated that theiron minerals such as hematite and limonite in the Australian iron ore were reduced as follows: Fe2O3?Fe3O4?FeO?Fe. Furthermore, the metallic iron particles produced by reduction increased in size with longer reduction times.

Jan 1, 2014

Compressive crushing is applied in crushing plants used in mineral, mining, and aggregate in-dustry for fragmentation of rock materials. From a global perspective, the total volume of crushed rock is massive and corresponds to several billion tons. All societies have to fulfil a daily need of rock material products and its derivatives such as metals and minerals. The business for metals and minerals is global while the aggregates production is mainly a local industry. This paper presents a broader overview of optimisation with respect to product yield, use of natural resources and energy consumption. High level plant optimisation of compressive crushing plants is covered as well as real-time optimisation and optimisation of single production units. Each of three optimisation areas are presented and a discussion around how these three areas will be able to communicate with each other is given. Several models, e.g. process performance behav-iour with respect to wear, as well as fitness functions can be common for all three areas. Well-defined and representative fitness functions are of the utmost importance in order to assure that the optimisation results reflect the production targets. It is concluded that great benefits can be achieved by linking together different areas of optimisa-tion. The future for compressing crushing lies, without a doubt, in tailored processes both with re-spect to machines optimised for each customer, plant parameters and operation routines as well as an on-line adjustment, which takes into account current information and control possibilities.

Jan 1, 2014

By M. Evertsson, K. Bhadani, E. Hulthén, M. Bengtsson

"Modelling and simulations for mineral processing plants have been successful in replicating and predicting predefined scenarios of an operating plant. However, there is a need to explore and increase the potential of such simulations to make them attractive for users. One of the tools to increase the attractiveness of the simulations is through applying optimization schemes. Optimization schemes, applied on mineral processing simulations, can identify non-intuitive solutions for a given problem. The problem definition itself is subjective in nature and is dependent on the purpose of the operating plant. The scope of this paper is to demonstrate two optimization schemes: Multi-Objective Optimization (MOO) using a Genetic Algorithm (GA) and Multi-Disciplinary Optimization (MDO) using an Individual Discipline Feasible (IDF) approach. A two stage coarse comminution plant is used as a case plant to demonstrate the applicability of the two optimization schemes. The two schemes are compared based on the problem formulations, types of result and computation time. Results show that the two optimization schemes are suitable in generating solutions to a defined problem and both schemes can be used together to produce complementary results. INTRODUCTION The comminution process for a mineral processing plant consists of multiple crushing and classification stages and aims to produce fine material to liberate ore from the minerals. The modelling and simulation of such processes are well established using static process models (King, 2001; Napier-Munn et al., 1996). A recent development in the dynamic modelling for such processes has shown further increase in fidelity compared to the static process models (Asbjörnsson, 2015). The developed simulations can be utilized to design, operate and control mineral processing plants based on the requirements of users (Bhadani et al., 2017). Typically, the requirements in the operation of the comminution process are conflicting in nature, as for instance, reduction of power draw by process units, maximization of production of fine materials, and increasing utilization of the process units. These conflicting requirements leads to a Multi-Objective Optimization (MOO) problem to operate a mineral processing plant. The MOO problems are normally referred to as non-linear problems and its fundamental understanding with respect to process behaviour is difficult to achieve."

Jan 1, 2018

Cenospheres is a sandlike hollow sphere component of the fly ash that is collected in coal-burning electric power generating plants. Metal coated particles have been widely used in industries. Magnetron sputtering method which was used to coat copper film on the surface of the cenospheres is a widely used coating technique in large surface metal coating. A newly designed equipment is used to make the fine particle coating can be carried out because the fine particle is hard to disperse and it must make the particle keep moving to let every direction of the particle be coated. The copper film coated is compact, smooth, even and without uncoated spots under the optical microscopy and SEM. The film has good affinity to the cenosphere surface. The film does not separate with cenoshpere surface even when the cenosphere is crushed. The XRD, SEM, XPS, SPM was used to study the copper film characteristic. It is shown that using this newly designed magnetic sputtering equipment can coat high quality copper nanofilm on the cenoshpere surface.

Jan 1, 2014

By Roberto Galery, Priscila Esteves, Braz Cardoso, Marcelo Stopa

"It was developed in this work a computational tool to aid in anomaly detection present in the operation of ball mills. The tool uses a torque estimator that is based on measurements taken exclusively in the drive motor. The ball mill equipment widely used in the mining industry has, inherent to its principle of operation, high energy consumption and low efficiency. These characteristics are accentuated when the mill operates outside the ideal conditions of velocity and loading. Direct measurement of these variables is extremely difficult because it requires the installation of sensors in moving parts of the mill. Thus, systems that can help monitoring the operating conditions and predict anomalies are useful because they contribute to improving the performance of the process, help to reduce the energetic consumption, wear on the mill surface and frequency of maintenance shutdowns. The detection strategy implemented in this work is based on the fact that operational anomalies such as an inadequate percentage of balls and incorrect angular velocity manifest itself as a change in spectral components of the torque signal in the mill driven by an electric motor. The mill torque was estimated by processing motor variables measured by sensors commonly used for control purpose and installed exclusively in the motor. The mill was operated at various fault operating conditions and signals from electric motor and vibration on the mill shaft were measured. The spectral components present in the estimated torque signal were then compared with signals from a vibration sensor in order to establishing a correlation with anomalous operation condition of the mill. The experimental results showed that the signals obtained has an excellent correlation with other variables obtained by direct measurement and have potential to be used to construct a system for automatic fault detection in the operation of ball mills."

Jan 1, 2014

By Y. Q. Qui

In the bauxite flotation process for desilication, the middling treatment mode is the important factor to raise the flotation recovery of the preparation concentrate. The middling treatment mode mainly depends on A/S and the size composition. However, similar ratio of A/S should not be the single factor of re-dressing, size composition plays an important role also. Re-dressing the middling mixed with the tailings of concentrated to the rough ground for desilication and the concentrate of scavenged to the fine ground for desilication to raise the recovery of 5.83%, when compared two flow sheet schemes.

Jan 1, 2014

By G. K. Nimal Subasinghe

The performance of Knelson Concentrators (KC) used in gravity gold circuits often rely on manufacturers recommendations for selecting operating parameters such as, fluidising water flow rate and cycle time. These parameters are not only dependent on the machine parameters but also on the feed characteristics such as, size distribution of the gold and gangue particles and the composition of its constituent minerals. Particles entering a KC experience a centrifugal acceleration due to the high bowl rotational speeds. The required centripetal force to maintain a circular orbit is provided by the fluid drag force created by inwardly moving fluidising water and the Bagnold?s force arising from the particle/particle collisions. When the fluidising water flow rate is low particles move towards the outer rim of the bowl forming a packed bed within the grooves. On the other hand, if the fluidizing water flowrate is high the bed expands and some particles would move towards the centre of the bowl and gets carried to the tailings stream, thereby reducing the amount of material retained within the grooves of the bowl. Based on a force balance on a particle captured within the KC, a criterion which can be used to predict the amount of material recovered in the bowl has been derived and validated by experimental data. It has been shown that this criterion may be used to demarcate the transition of the bed from a packed-bed state to a fluidised state depending on the fluidizing water flowrate. By identifying the conditions for the optimal expansion of the bed comprising different constituent mineral particles, it is possible to estimate the optimal fluidising water flow rate that would maximise gold recovery while minimising gangue recovery. It was also observed that the accumulation of valuable mineral in the bowl takes place by the displacement of the gangue particles in the bed by the incoming heavy mineral particles. The kinetics of this segregation process was also studied using synthetic mineral mixtures. The experimental data suggests that this process follows first order kinetics and that the build up of heavy mineral reaches a maximum which could be used to identify the optimal cycle time. In this work, the suitability of the above model in optimizing the performance of a KC have been reviewed. Also the necessity and merits of testing an unaltered

Jan 1, 2014

By L. Y. Wang

In order to produce the iron and steel products with high quality and decrease the output of steel tailings, the quality of molten iron is a critical factor for iron and steel companies, especially the content of sulfidic in molten iron. Hot metal pre-treatment, an important and effective method to desulphur, is widely used in steel production. Millions of tons of slag from desulphurization and slag skimming are produced each year in China, and many more times this amount is stored in slag dams because of the lack of effective means to deal with it. In order to achieve the goal of sustain-able development, recycling these slag becomes necessary. The main objective of this paper is to study the composition characteristics of slag that from desulphurization and slag skimming. The sample was obtained from Anshan Iron and Steel Group Corporation, processed by hot metal pre-treatment. In this study, the chemical components and the mineral compositions of sample were tested. The results of chemical components and iron chemistry phase analysis showed that the iron and sulphide content in this sample were high, and the iron products existed mainly in the form of magnetite, metallic iron, ferrosilite. X-ray diffraction (XRD) and scanning electron microscope (SEM) results indicated that the sample included metallic iron, ferrate, wustite, metasilicate, aluminate, aluminosilicate, white lime and soon. Grading magnetic separation test work showed that magnetic separation was an effective method to recovery iron products and decrease the sulphide content in concentrate, and the tailing could be used as the raw material or padding in cement production.

Jan 1, 2014

By R. K. Logric

Bor flotation tailings are very interesting from two reasons: first, is having due value presently, and second represent serious pollutant into this region of Balkan. This paper is only one small part of investigation about processing of valuable minerals from tailings, and desulphurization of this biggest pollutant in the same time, by refloating. The main objective of this work is to pay attention on this problem for resolve greatest environ-mental problem of Serbia and Balkan in the nearly future. Bor is potential regional risk spot, since that failure of its tailings dams would release high amounts of toxic materials that would reach the Danube River. The basic goal of this experimental investigation was finding some possibility for flotation tailings treatment by classical froth flotation. In order was obtained material effect through copper recovery, and environmental protection by moving the rest of reprocessing into the safe place. The work present obtained results of laboratory tests in two laboratories: laboratory of mineral and recycling technology at the faculty in Bor, and laboratory of department of mineral processing of ITNMS in Belgrade.

Jan 1, 2014

By G. J. Mei

Separation of hematite and iron-containing silicate gangue - aegirine by Flotation using fatty acid collector and (NH4)2SiF6 depressant was investigated in this paper. The flotation tests with single minerals show Ammonium hexafluorosilicate (AHFS) is a selective depressant for aegirine in hematite flotation in weakly acidic medium, which can strongly reduce the flotation recovery of aegirine in the pH range of 4~5 while has no evident effect on the flotation of hematite. The results of flotation tests with actual ores show the separation of hematite from aegirine gangue by forth flotation was possible, and good selectivity was achieved. Chemisorptions were observed on aegirine mineral surface treated by AHFS solution by using SEM and IR spectrum measurements. On the basis of coordination chemistry, a comprehensive mechanism, which reasonably explains the selective depression of AHFS for iron-containing silicate, is also proposed.

Jan 1, 2014

By X. Tong

Flotation researches of indium-beard marmatite from the Dulong multi-metallic ore in the Yunnan Province of China has been studied in order to improve the grades and recoveries of zinc and indium of the zinc concentrate in the Dulong concentration plant. The experimental results have shown that copper sulfate mixed with a chemical reagent X-1 as the activator in the marmatite flotation produced a much better beneficiation than copper sulfate alone, increasing the zinc and indium recoveries of 10% and 6%, respectively, while the concentrate grades were unchanged. Also, the new activator acted well around pH 10, allowing large savings on lime consumption in the marmatite flotation. In addition, it has been found that a sufficient activated time of activator with ore slur-ry in the flotation is needed to achieve good beneficiation of the marmatite ore.

Jan 1, 2014

By K. Saberyan

In this study the extraction of zirconium and hafnium has been investigated by solvent extraction using Cyanex 302 in various media such as nitric, sulfuric and hydrochloric acid has been investigated. Effect of various parameters such as type and acid concentration, extractant concentration, type of diluent, equilibrium time, various foreign ions and finally type and concentration of strip-ping agent have been studied. The results showed that nitric acid was optimum media for extraction of zirconium and hafnium. The extraction of zirconium and hafnium occurred quantitatively in the concentration of higher than 4 M nitric acid but in hydrochloric acid media, quantitative extraction obtains over 8 M HCl. In sulfuric acid media, extraction of zirconium and hafnium is negligible. Stripping studies showed that the optimum reagent for stripping was 0.5M sulfuric acid.

Jan 1, 2014