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By Shen Zhengchang

Based on the flotation features of coarse particle mineral, a new type of impeller & stator unit is developed. Particles suspension state generated by this impeller & stator unit under different speeds are tested in laboratory, and critical impeller speed suit for coarse particles flotation is presented. Comparing particle suspension parameters of the new impeller & stator unit with that of KYF impeller and stator unit, it comes up that the distance between the interface of two slurry circulation channels and the cell bottom is larger in the flotation cell with new impeller & stator unit. The test results indicate that the new type of impeller & stator unit is suitable for processing coarse particles due to its good suspension capacity for coarse particles. Keywords: coarse particles, flotation, suspension, critical speed, impeller and stator unit

Sep 1, 2012

By W. Fander, Zhonghan Zhang, T. Choo, J. Enraght-Moony

"This paper describes the mineralogical and metallurgical procedures used to determine the recovery and concentrate grade of heavy oxide minerals occurring in lode deposits. The data produced also provide vital information to the processing engineers, which allows them to develop the most suitable flow sheet for that particular heavy mineral, here called an Economic Oxide Mineral (EOM). It demonstrates how results are interpreted to ensure that the proper process is used at each treatment stage to optimise recovery and to produce the most suitable concentrate at that point. Reference is made to some of the current equipment and techniques that can be used to process EOMs. The paper shows that when assessing the economic potential of a new ore body, or existing ore treatment plant, ore characterisation (OC) is necessary. This is especially true for EOMs such as cassiterite (SnO2), wolframite ((Fe, Mn, WO4,) pyrochlore ((Na,Ca)2Nb2O6(OH,F)), and tantalite (MnTa2O6) where often what seem to be small changes in ore types can have major effects on recovery and concentrate grade. Due to advances in flotation technology scheelite (CaWO4) in some deposits can be less vulnerable to OC variability than other EOM’s. Thorough mineralogical examination is shown to be the fundamental basis of correctly undertaking OC. This is because mineralogical analysis identifies each of the steps required to ensure that all ore types and zones are recognised, and differences explained, and shows the benefit in using reference samples to compare differences in the ores. The OC methods used for EOMs containing metals such as tantalum, tin, tungsten and niobium are similar; if two or more of these EOMs occur in one deposit as separate minerals, then OC will show when and how these minerals should be separated. The OC techniques described for EOMs can also be tailored for other heavy minerals, precious metals and graphite."

Jan 1, 2014

By O. N. Mohanty, S. Mohan Rao, N. D. Rao, T. Mukherjee, P. V. T. Rao

"Chromite ore is an indispensable raw material in the manufacture of ferro-chrome and charge-chrome, which are used for the production of stainless and other alloy steels. The demand for chromite ore is ever increasing because of increasing consumption of these steels. Keeping this in view, Tata Steel is keen to recover values from fines and wastes, and also to produce value added products from their captive chromite mines and its processing plants.Tata Steel has its captive chromite resources at Sukinda, Orissa. They contain two ore types, i.e. (i) Ferruginous and (ii) Siliceous. The generation of off-grade ores is an increasing trend and simultaneously customer quality requirements are becoming ever more stringent. The ferruginous type ore also contains a considerable quantity of in-situ fines (~20% particles below 0.5 mm) that compound the beneficiation problem.In many places, in India and abroad, mined non-marketable off-grade and low grade chromite ores are upgraded by using either simple classification techniques like screw classification, hydrosizing, hydrocycloning or conventional gravity concentration processes such as Heavy media separation, Jigging, Spiraling, Tabling etc.At Tata Steel, the ferruginous type ores are treated in Chrome Ore Beneficiation (COB) Plant that comprises: a crushing and grinding circuit; a classification circuit using hydrocyclones; and a beneficiation circuit using 4 stage spirals in the coarse circuit (-0.5+0.1 mm) and 3 stage spirals & tables in the fine circuit (-0.1+0.038 mm). In this process, 3 types of tailings are being generated and together analyses about 17 % Cr2O3, which is high. From the present operation the chromite recovery is around 70% and could not produce coarse concentrates (+0.5 mm size). Whereas the siliceous type ore is treated in the Lumpy Ore Processing (LOP) plant, consisting of crushing-washing & classification-hand sorting operations, to produce marketable grade lumpy ore and –10 mm de-slimed fines. These fines are intermittently treated in the COB plant. The higher silica content (greater than 1%) and low Cr/Fe ratio (less than 2.8) are the problems with these concentrates."

Jan 1, 2003

Micro-fine disseminated molybdenite was ground in a laboratory stirred mill using steel media and zirconium media respectively. The floatability of ground molybdenite and slurry chemistry was investigated. It was found that the total recovery of ground molybdenite using zirconium media was higher while the pH and Eh of the slurry are lower than that using steel media. When steel media was used, iron oxy-hydroxides had been generated coated on the surface of molybdenite, and decreased the floatability of molybdenite, especially of the -10µm particles. The iron and lead oxy-hydroxides was generated by the reaction between steel media with pyrite and galena associated with molybdenite. It was also found that changing the grinding media to inert can benefit the flotation of molybdenite. Keywords: stirred mill, grinding environment, floatability, micro-fine disseminated molybdenite, fine grinding

Sep 1, 2012

By Slobodan B. Vujic

"Some twenty years ago, during construction of flotation in the “Veliki Krivelj” copper and non-metallic mine Bor, a computer supported system for remote controle of technological process was installed. Nowadays, the major part of equipment of this system is worn-out and technically old-fashioned. Having this in mind a decision was made to design a new computer supported information-management system for Flotation. The paper presents a concept and features of project solutions.For the requirements of remote monitoring and management of technological process in Flotation of “Veliki Krivelj”, Copper and non-metallic minerals mine in Bor, Yugoslavia (hereinafter: CNM Bor), a measuring-regulation equipment was implemented and a computer control system, adjusted for that time, built some twenty years ago. The major part of this equipment is today worn out and technically out of date.Having estimated that production and business activities could hardly be more efficient, operative and successful on one hand, and available mineral and other resources rationally exploited, the CNM Bor made a decision in 1999 to improve information-management function of Flotation. The idea was that the set task be realized through development and introduction into practice up-to-date integrated and computer-supported production-business information-management system. The first logic step in completion of this task refers to engineering-creative determination of information management system (hereinafter: IMS), namely to project elaboration.When considering the real system from technical, technological, organization, monitoring-management, logistic and business aspects, the Project on IMS of Flotation, should provide a rational, modern and, for the real system conditions, complete solution. The Project solutions should be based on the most recent knowledge from computer and measuring-regulation technics as well as from CIM concept (Computer Integrated Manufacturing)."

Jan 1, 2003

By Markus Dammers, Christopher Robben, Hermann Wotruba, Christian Schropp

"In most underground mining processes the entire extracted ore is transported from underground workings to surface processing plants for separation of valuable minerals and gangue material. Most of the transported material consists of barren rock with negligible metal content, especially for low grade deposits, such as in the copper or gold metal ore mining. Increasing mining depths result in higher costs for transportation and hoisting. Therefore, rejecting waste rock as soon as possible from the material stream gains importance. The concept of resource to product integration in the form of earliest waste rejection in combination with subsequent backfilling follows the philosophy of ‚leaving waste underground?. Implementing mineral processing underground can lead to less required mass movement to surface, hence reducing transportation and hoisting costs. At the same time, rejected waste can be used as backfill to increase extraction rates by reducing pillar volumes. In the mill, a stable high grade feed leads to decreased specific operating and investment costs as well as increased productivity and recovery. These effects as a whole have a large potential to reduce cut-off grades so that resources can be turned into reserves. Within the I²Mine (Innovative Technologies and Concepts for the Intelligent Deep Mine of the Future) project of the European FP7, investigations are carried out by the Unit of Mineral Processing of RWTH Aachen University, the Institute of Mining Engineering I and TOMRA Sorting Solutions | Mining. One aim of the cooperation is to develop new concepts for a comprehensive integration of near-to-face processing in combination with backfill into the overall underground mining process. Effects on up-, down- and side-streams are investigated to prove the potential of resource to product integration in comparison to common underground mining systems and processing methods."

Jan 1, 2014

By Gideon Chitombo

"Mining is a "continuous" process of dependent breakage and materials handling stages, from the initial breakage of the in-situ rock, extraction from the pit or underground, and finally to the surface stockpile and downstream processing. Over time, underground and in-pit mining activities diverged into two separate disciplines, each using a variety of in-situ breakage techniques and surface activities, with processing techniques dependent on mineralogy or grades. This artificial separation of underground and open pit activities was exacerbated when the two became increasingly managed as separate cost centres rather than as an integrated unit. Mass mining essentially began in 1903 when metallurgist Daniel Jackling initiated the world’s first open pit, mining system at the Bingham Canyon porphyry copper deposit in Utah. The term mass mining has since been construed to mean large open pits and cave mining methods, including their variants. These methods are largely non-selective, involving the mass extraction of a deposit irrespective of the uneven distribution of grade and mineralogy. The advantages of mass mining have historically applied mostly to low grade, large scale deposits. With the depletion of mineral reserves closer to the surface, however, new deposits are deeper, lower grade and mixed with more impurities. These and other factors make extraction more difficult and costly. Mass mining is moving rapidly into a new and less certain environment where revolutionary changes are required to effectively deal with future challenges which are technical, economic and environmental (licence to operate). This keynote address presents current initiatives being considered for the next generation of both underground and surface mass mining systems in order to significantly reduce lead times and mining costs (CAPEX and OPEX), substantially increase productivity and meet license to operate requirements. The address is designed to solicit discussion on how better integration of mining and processing can become a platform for these next generation of mass mining systems and can also help the industry deal with the future challenges."

Jan 1, 2014

By Vladimir S. Zharov, Vyacheslav A. Tsukerman

"Conceptual imitative dynamic model of developing enterprises for medium and long-term period permitting to ensure coordination of interests of the enterprise and territorial environmental authorities has been developed to enable the process of the prognostication and management of a concentrating mill development, in which a symbol language and terminology familiar to the manager of the company are applied. An algorithm of practical application of this model of company development was elaborated as well as a general methodological approach to the prognostication of the development and procedures of its implementation. The general methodological approach to the implementation of the model has been defined. Within the framework of system approach, a concentrating mill is considered as a subsystem of an ore mining and processing company or a mining and smelting one. A concentrating technology is considered in dynamics, its change is determined by the task of making the company operation profitable. Technological indicators are secondary relative to financial and economical indexes. At the same time, technological and economical indexes are determined in their interrelation with ecological parameters. The elaborated model allows us to estimate all necessary economic, financial and technological indexes in their interrelation both for the company as a whole and as separately redistributed estimating the basic prognostication documents - accounting balance-sheet, profit and loss report, as well as the funds flow statement. When varying the managing parameters, all necessary result-producing financial and economical indexes are estimated and a need in and a possibility of an external funding by various sources are considered.The implementation of the model enables one to determine the required scale of production capacity, as well as the amount of raw-material resources needed. In case of shortages of the latter, there should be considered various scenarios of the production capacity enhancement or the possibility of commissioning of new sites or deposits and introduction of improved technologies."

Jan 1, 2003

By L. S. Zhou

HermesTM metal magnetic liner (MML) has been invented and manufactured by China Metallurgy and Mining General Co. (CMMC). This paper describes its mechanism, structure, magnetic field distribution, application, economic benefit and safety performance. The 10 years? service life in Benxi Steel?s Waitoushan Mine, along with 6 years? technological analysis on its application in 5500mm×8800mm (diameter × length) ball mill in Anshan Steel?s Diaojuntai mineral processing plant, has proved its advantages such as super reliability, long service life, light weight, thin thickness, low noise and short payback period. It has also demonstrated its positive effects on the grinding process such as high productivity, energy-effective performance and low consumption of grinding media. It reduces labour intensity and improves working conditions, due to its easy installation, free maintenance and the fact that it doesn?t require fastening bolts or cause slurry leakage. It is de-signed scientifically in accordance with the varieties of processing lines, mill specification, ore type and grinding media, and has been applied in different grinding processes for magnetite, hematite, gold ores, nonferrous ores and other materials. HermesTM MML has three types of products: General, Composite and Heavy-duty. They are designed to meet the requirements from customers in China and abroad. So far, more than 400 sets of MML have been applied in ball mills with diameter rang-ing from 1500mm to 5500mm. It has become highly popular in American market recently due to its safe and effective performance.

Jan 1, 2014

By Chao Li, Kym Runge, Saeed Farrokhpay, Dee Bradshaw

"It is well known that froth phase has a controlling influence on the overall flotation performance. Froth recovery is expected to be affected by froth transportation behaviour. The latter has been represented by different volume balance and energy balance based models. In froth transportation models based on a volume balance, the froth phase is divided into different zones. The total froth residence time is the sum of the time spent in each zone and is dependent on the cell geometry, bubble burst rate and the position that bubbles enter into the froth phase. Alternatively, the froth transportation model based on an energy balance treats the froth phase as a block. In this model, froth height above the concentrate lip is being predicted by minimising the energy of the system which is dependent on the froth geometry, froth stability and froth rheology. The froth height can be used to calculate the froth efficiency of delivering mineralized bubbles from the pulp to the concentrate lip. This paper critically analyses the current models of froth transportation in flotation, and examines the limitations of these models. The importance of froth rheology, which is the resistance to the froth flow towards the discharging weir, in determining froth transportation, is also highlighted."

Jan 1, 2014

By Kwang Soon Moon

Liquid ? liquid reactions such as solvent extraction in hydrometallurgy and BTX extraction in petrochemical industry has long suffered from the long retention time mainly due to the limited interfacial area caused by the immiscibility between water and oil phase, requiring typically very large perfect mixer type reactors and tall adsorption towers. A novel spray reactor for immiscible liquids; that is the KISEI Nozzle Reactor (KNR) was introduced, enabling the drastic increase in the interfacial area between the reacting immiscible liquids. Various spray mechanisms were applied in materials processing, e.g. spray drying, powder metallurgy, and aerosol industry, but not in hydrometallurgy. The KISEI Nozzle Reactor(KNR) was fully developed and used in production of biodiesel from the immiscible triglycerides and methanol. An experience with a full production plant facility is briefly discussed in the current paper. With the fog-like methanol spray in oil medium, the trans esterification reaction was almost instantaneous, and transformed the traditional batch trans esterification process into a continuous production process. And above all, with no moving parts in the KISEI Nozzle Reactor (KNR), the process requires minimal operation and maintenance costs. Keywords: immiscible liquids reaction, nozzle spray reactor, continuous biodiesel reactor, hydrometallurgy, organic extraction, micro emulsion

Sep 1, 2012

By G. P. Karmakar, K. K. Chandan

"The drilling mud is an essential part of the drilling process, which plays a major role in keeping safe and efficient oil and gas well drilling. In the oil industry, bentonite clay dissolved in water produces the simplest type of drilling muds. Bentonite clay contains montmorillonite particles. These particles are dispersed uniformly in water and such dispersions are used in various industrial products like paints, ceramics, pesticides and drilling muds. The bentonite clay easily dissolves in water and increases the viscosity of the water, which is one of the most important properties of a drilling mud. Bentonite has the highest swelling capacity, which is responsible for building up of the viscosity of the clay-water system. The flocculation behavior of bentonite is one of the major concerns for the performance of the water-based drilling mud in the oil and gas well drilling process. The behavior of drilling mud greatly depends upon the quality and quantity of bentonite clay, as well as the additives that are used in their formulations. In this work, a comprehensive study has been carried out to find out the effect of added polyacrylamide (PAM) polymer, surfactant, pH and salt concentrations on the dispersion/ flocculation characteristics of bentonite clay-water system. It has been observed that the increase in PAM dosage reduces the residual turbidity and improves the settling rate of the bentonite particles. The flocculation rate has also been found to be better under higher pH conditions. The combined effect of salt concentration and PAM dosage improved the overall flocculation efficiency of the system.INTRODUCTIONIn the oil industry, bentonite clay dissolved in water produces simplest type of drilling muds. Bentonite clay containes montmorillonite particles. These particles are dispersed uniformly in water. Such dispersions are used in various industrial products like paints, ceramics, pesticides and drilling muds (Akther et al., 2007). The bentonite clay easily hydrates in water and increases the viscosity of the mud system (Razi et al., 2013; Meng et al., 2012). Bentonite clay in the drilling mud increases the viscosity which is one of the most important prop erties of a drilling mud. Bentonite has the highest swelling capacity, which is responsible for the building up viscosity of the clay-water system (Sonmez et al., 2013). The drilling mud is an essential part of the drilling process, which plays a major role in keeping a safe and efficient oil or gas well drilling (ASME, S. S. C., 2005). The flocculation behavior of bentonite is one of the major concerns for the performance of the water-based drilling mud in the oil or gas well drilling process. This behavior of drilling muds greatly depend upon the quality and quantity of bentonite clay, as well as the additives that are used in their formulations (Yu and Amanullah, 2005; Akther et al., 2007). Bentonite particles form aggregate under certain conditions including high temperature, and high concentration (Luckham and Rossi, 1999). If the quality of bentonite is not sufficient to accomplish intended viscosity of the muds, it is essential to add certain additives to increase the viscosity and prevent aggregation of the system (Razi et al., 2013). The anionic polymer bearing sample can build up inter-particle bonds between the polymer and clay particles. The addition of various additives like, polymers control the dispersion and enhance the viscosity of the mud by controlling the flocculation of montmorillonite particles in bentonite dispersion (Heller and Keren, 2002; Mahto and Sharma, 2004)."

Jan 1, 2018

By Przybycien Krzysztof, Tumidajski Tadeusz

"Materials being the feed to mineral dressing plants are the mixture of ore minerals having different physicochemical properties among others, especially susceptibility on crumbling. During exploitation of material and their preparation to communition the big number of narrow classes comes into being and they have different properties. The determination of common communition laws of multicomponent (on account of size and mineralogy) materials leads to the estimation of mutual influence of narrow classes and their rates, taking into account their endurance and mineral density, on general ratios and their simultaneous crumbling.If we try to accept the grain membership to the certain component as the differing feature, we can write the balance equation as: ( ) ( ) S= = k i i i g x p f x1where: fi – density functions of one type distribution and of different statistical moments (characterising the homogeneous materials grinding), pi – “stirring” proportions of each components, S== k i i p 1 1 . From the point of verification view of detailed versions of this equation the inverse operation should be done: in the base of the components’ mixture grinding results and the results of components grinding the legitimacy of equation should be checked.The using of finished distribution mixtures’ theories to the grinding process analysis allows, first of all, to verify the assumption of grinding independence of individual feed components. Talking more generally it would lead to the comparison of grain size distributions, obtained by individual components grinding from the defined in the mixture distributions theory calculations. One of experimental and calculation results for artificial mixtures of galena and dolomite is presented on figure below (df means distribution function)"

Jan 1, 2003

By L. Bbosa

Positron Emission Particle Tracking (PEPT) and the Discrete Element Method (DEM) are used to investigate Power Draw in a laboratory scale tumbling mill. The mill is run dry in batch mode at different speeds using mono-size charge of glass beads, and is mounted along with a torque transducer to measure 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 PEPT and DEM 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. Spatial distributions plotted from this approach highlight the regions of the mill that draw the greatest power. A second technique to obtain Power Draw from DEM data which sums particle forces against the mill geometry is similarly found to accurately predict mill power with lower statistical error. Keywords: Power Draw, PEPT, DEM

Sep 1, 2012

By Yuexin Han

The wet preconcentration of haematite, comminuted by high-pressure grinding roller was studied, using the cylindrical ferromagnetic medium. The effects of various factors including rod diameter, rod gap and background magnetic field intensity (BMFI) on the performances of preconcentration for different size fractions and the force analysis of single mineral particles with different diameter in the separation zone were emphatically investigated. The results showed that as the rod diameter increased, the rod gap decreased, and the BMFI increased the tailings grade and the tailings yield reduced while the concentrates recovery raised that was regardless of variations in feed size distribution. For the -3.2+0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 7 mm at BMFI of 454kA/m is used to get a higher performance. For -0.18mm size fraction preconcentration, the magnetic medium with a rod diameter of 4 mm and a rod gap of 4 mm at BMFI of 263kA/m is used to get a higher performance. After the classifying preconcentration, at the optimum condition, the overall concentrate grade increases by 9.56 percentage points and the concentrate recovery is up to the 82.67% with a tailing grade of 10.68% and a tailing yield of 40.31%. The magnetic force, exerted on weekly magnetic minerals was proportional, to the specific susceptibility and square of BMFI. For the same BMFI, the magnetic capturing force on coarse particles increased, and that on fine particles decreased with the increasing of rod diameter. For the lean locked-particles, considering the gravity and viscous resistance of particles, rods with a big diameter were beneficial to the capture of coarse particles and had no influence on the capture of fine particles, while rods with a small diameter were good for the capture of fine particles and not suitable for the capture of coarse particles of lean locked-particles. Keywords: low grade haematite, high-pressure grinding roller, high intensity magnetic separation, pre-concentration

Sep 1, 2012

By Ghislain Bournival, Cagri Emer, Seher Ata

"It is well known among flotation practitioners that the contact angle can be correlated with the amount of material recovered from feed by flotation. The contact angle of solids can easily be modified by the addition of a collector. However, some collectors also have frothing properties thus altering the solid and bubble surface properties simultaneously. To avoid this problem, a technique has previously been used in which silanol groups are attached to the surfaces of the particles, but this method has its own problems. In this work, silica particles with various surface hydrophobicities were prepared using an esterification process. By using alcohols with different hydrocarbon chain lengths, from 4 to 12 carbon atoms, surfaces with a wide range of contact angles could be prepared. The technique was used in the modification of silica particles that were tested in a fluidized bed flotation column, and a laboratory mechanical flotation cell. In parallel experiments, dodecylamine (DDA) was used as a collector. It was found that irrespective of the type of flotation machine and surface preparation method, there was a close correspondence between flotation recovery and the contact angle of the particles. The silanation process has known drawbacks relating to the presence of moisture during the reaction, and the stability of the silane coating after it is been prepared. Esterification does not suffer from these disadvantages. This work has shown that the esterification technique is a robust alternative method for preparing hydrophobic quartz surfaces."

Jan 1, 2014

By M. Lundström, J. Aromaa, S. Seisko

"Gold dissolution was investigated in ferric chloride media, promoted as one of the most promising alternatives for cyanide-free gold leaching. The characteristics of gold open circuit potential (OCP) and its relation to gold dissolution rate was investigated. Furthermore, the reaction mechanism of gold dissolution in ferric chloride leaching was discussed. The effect of solution variables, [Fe3+] = 0.02–1.0 M, [Cl–] = 2–5 M, T = 25–95 °C and pH = 0–1.0, on OCP and dissolution rate were studied electrochemically using rotating disk electrode (RDE) and linear polarization resistance (LPR) method with ?cyc = 1000 RPM. The investigated gold OCPs in ferric chloride solutions were found to vary between 597 and 688 mV vs. saturated calomel electrode (SCE) and gold dissolution rates between 1.2·10–5–5.0·10–4 mol s–1 m–2. Increase in temperature (25–55 °C) and ferric concentration (0.02–1.0 M) changed OCP into more positive values, while increase in chloride concentration (2–5 M) decreased it. The logarithm of gold dissolution rate was shown to increase linearly with increasing OCP at the temperature range 25–95 °C, ferric concentration range 0.02–0.5 M and chloride concentration range 2–4 M. A notable increase in the gold dissolution reaction rate was evident at T > 55 °C. INTRODUCTION Currently cyanide leaching is the predominant method used in gold production from primary raw materials (Marsden and House, 2006). However, since the Baia Mare disaster in Romania in 2000, the use of cyanide has been the subject of international concern due to the toxic nature of the chemical posing a significant health threat if exposed to the ecological entities (Hilson and Monhenius, 2006; UNEP/OCHA, 2000). Therefore, several countries e.g., Costa Rica, Czech Republic, Germany, Hungary, Turkey, many states of the USA and provinces of Argentina, have started to ban or limit cyanidation via legislation (Laitos, 2012). Thus, alternative solutions, such as thiourea, thiosulphate, oil-coal agglomerates as well as halides have been investigated in order to replace cyanide as lixiviant (Adams, 2016; Aromaa et al., 2014; Aylmore, 2005; Hilson and Monhemius, 2006; Lampinen et al., 2015). Ferric and cupric chloride leaching have been reported to have advantage over cyanidation being capable to dissolve refractory gold minerals, without pre-treatment such as pressure oxidation or roasting (Angelidis et al., 1993; Lundström et al., 2014; Marsden and House, 2006; van Meersbergen et al., 1993). According to Aylmore (2005), 4% of publications for alternative lixiviants to cyanide in gold leaching were within category oxidative chloride processes including aqua regia and acid ferric chloride leaching. Further, some patents have been granted for ferric chloride leaching of gold (Abe and Hosaka, 2010; Lundström et al., 2016)"

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. These ores require mineral processing to remove the sub-strate/nuclei rock before smelting. This paper reviews experimental results of previous investigations. Observations and analysis of 10 samples from different localities were carried out and it was found that the liberation ratio of crushed product was high even at coarse size fraction, 0.5mm to 4mm. Experimental and calculated results in the smelting stage confirmed that the separation product satisfies the standards of the subsequent smelting process if the substrate/nuclei rock is removed from the 0.5mm to 4mm fraction with high separation efficiency. There was a density difference between the substrate/nuclei rock and the ferromanganese component. Thus the coarse sized sample was treated with gravity separation; air table separation was used as a dry method and jig separation as a wet method and high grade values with high recoveries were obtained by both kinds of gravity separation.

Jan 1, 2014

By Q. Shi

An investigation into the hydrophobic aggregation of ultrafine smithsonite in surfactant solution has been undertaken through a combination of hydrophobic flocculation experiments, zeta potential measurements, surface tension measurements, and contact angle measurements. The experimental results have revealed that the behaviors of hydrophobic aggregation were closely correlated with the particle hydrophobicity, but they were not lowered byte change of the particle surface charges due to surfactants adsorption. On the other hand, the liquid (solution) surface tension (?LV) plays an important role in hydrophobic aggregation, and the hydrophobic aggregation could not occur below the critical liquid (solution) surface tension (?c). Meanwhile, this flocculation has been observed to require sufficient stirring strength and magnitudes of kinetic energy input to achieve the maximum aggregation degree. From the microflotation results, it has been found that the flotation kinetics response of smithsonite fines is markedly improved due to sufficient stirring strength, and the stirring strength influenced the floc flotation in a manner quite similar to their influence on the hydrophobic aggregation, suggesting that the formation of hydrophobic flocs is a promising means to recover smithsonite in the fine size range.

Sep 1, 2012

By Kari Niiranen, Patrick Krolop, Viktoria Töyrä

Luossavaara-Kiirunavaara AB (LKAB) operates an iron ore mine, three beneficiation plants and three pelletizing plants in Kiruna, Sweden. The current methods of separation in the beneficiation plants are wet low intensity magnetic separation (WLIMS) and reverse apatite flotation, where the WLIMS stage is regarded as the crucial part of silica separation from the ore. Currently, the high-grade iron ore deposit of Kiirunavaara has a low grade of silica in situ, of approximately 3.0% SiO2, but the silica grade is expected to increase in the deeper parts of the deposit with a complex silicate mineralogy. An increasing silica grade will affect especially the production of direct reduction pellets (LKAB DR Oxide Pellets), one of the main products of LKAB in Kiruna with an average silica grade of under 0.75% SiO2. The silica grade in the magnetite concentrate is normally limited to a maximum level of 0.55% SiO2 in order to achieve the required chemical composition in the pelletizing process. In order to study the possibility to reduce silicate content in the magnetite concentrate (pellet feed) in the beneficiation plants in Kiruna obtained by wet low intensity magnetic separation (WLIMS), enlarged mineral processing test work was carried out in the LKAB’s mineral processing laboratories in 2016. The test work consisted of comminution, low intensity magnetic separation and reverse cationic silicate flotation at laboratory scale, complemented by screen analysis, chemical assays and mineralogical investigation. The results of these mineral processing test work showed that the magnetic separation is not sufficient to reduce the silica content in the magnetite concentrate, particularly in the case of the high-SiO2 ore type B2-a. The reverse cationic flotation can be regarded as a possible solution to reduce the silicate content in the magnetite concentrate obtained by WLIMS and to achieve the required silica grade of less than 0.55 % SiO2 in the pellet feed. The results of this study provide a good basis to understand the behaviour of different silicates in the existing beneficiation process. Furthermore, it serves valuable information for development of new beneficiation processes and for investment in new equipment at the beneficiation plants in Kiruna in the future.

Jan 1, 2018