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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 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 Luís Marcelo Tavares, Juliana Segura

Comminution is one of the most energy consuming stages in a mineral processing plant. This consumption is not only related to the power supplied to equipment, but also to the indirect or embodied energy, mainly associated to materials that are worn during operation, including grinding media and liners. Until recently, preparation of iron ores in Brazil did not use comminution intensively, given that plants mainly produced sinter feed, natural pellet fines, besides lump ore. However, with decreasing ore grades, size reduction now occupies a centre stage in nearly all new plants. Technologies used up to date for processing low-grade iron ores in Brazil, in particular itabirites, have consisted of three or four stages of crushing followed by ball milling. A number of new plants are either being built or are currently being designed that will process the same type of ore, so that engineers are investigating alternative comminution routes. The paper analyses comparatively four comminution routes for processing a particular itabirite ore, many of which using technologies and layouts that have not yet been used in such application. Using data from bench scale and/or pilot-plant tests, the different routes are compared on the basis of sustainability principles in accordance to the Brazilian energy matrix, which is quite particular. It is concluded that if the sustainability criterion is used, then the optimal route would correspond to a circuit that uses HPGR technology with truncated feed followed by ball milling. Given the particular case of itabirite iron ores and specially to the one in the present work and the source of Brazilian energy, it is evident that indirect energy expenditure in comminution plays a significant role in greenhouse gas emissions when compared to direct energy, being the reason for the great attractiveness of HPGR technology. Evidently that these will have to be balanced against CAPEX, OPEX, NPV and other qualitative criteria, which can certainly lead to a different optimal circuit.

Jan 1, 2014

In this study, the effect of different regrinding conditions on the depression of fine pyrite at the cleaner stage was investigated. The regrinding condition was manipulated by different grinding media (stainless steel and mild steel). It was found that, after regrinding with mild steel grinding media, the flotation recovery of pyrite is much lower than with stainless steel grinding media, and it is more difficult to restore by adding more collector. This means, regrinding with mild steel grinding media may depress the pyrite flotation more strongly. The copper activation of pyrite during regrinding was also studied. It was found, that the mild steel grinding media is more beneficial to copper activation than stainless steel media. Additionally, the analysis of pyrite recovery based on the particle size indicated, that the fine particles are more susceptible to different grinding environments than intermediate and coarse particles and therefore are more easily depressed with a much lower flotation recovery.

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 Narasimha Mangadoddy

The complex nature of multi-phase flow in dense medium cyclones has restricted plant operators and designers to rely on empirical equations for predicting the performance. A number of empirical cyclone models have been developed in the past (Wood, 1990; Dunglison, 2002). In recent years, this subject has been broached with computational fluid dynamics (CFD). Most of the CFD models have not considered the correct rheological behavior of magnetite medium while simulating the medium segregation inside the cyclone. These models mostly predict excessive underflow volumetric flow rates. In this paper simulations of magnetite medium in a dense medium cyclone, were conducted in FLUENT where the particle phases were simulated using the modified Mixture model. The turbulence was resolved using Large Eddy Simulation (LES) model. The rheological behavior of medium was considered in the form of Granular viscosity, Newtonian and Non-Newtonian models corrected with particle loadings and fraction of ultrafines. Multi-phase simulations using granular viscosity option although predict the overall split product medium densities reasonably close to experiments, the mixture viscosity values are restricted to substantially lower values, similar to water viscosity. Simulations using Newtonian viscosity model corrected with particle loading, and fine fraction below 53µm size is predicting overall mixture viscosity levels well over water viscosity levels, but under predicting the under flow the underflow medium density. Multi-phase simulations using Non-Newtonian Herschel-Buckley model, calibrated for superfine magnetite medium measured viscosities, is closely predicting the medium segregation with gamma ray tomography data. Overall predicted product medium densities, underflow volume split are close to the experimental data. This model is can be further used to simulate coal portioning and hence in developing new designs.

Sep 1, 2012

By I. Blayda

The purpose of this work is to study and make comparative analysis of germanium extraction and related valuable components of the sublimates from the burning of domestic power coals (product 1) and germanium sulfide materials, which are a waste of lead-zinc production (product 2), by traditional chemical methods (distillation of germanium in the form of tetrachloride from raw and preliminary burning source) and by microbial bioleaching of sulfur-oxidizing bacteria. The dependence of the germanium extraction by chemical methods from phase composition of the initial raw materials was installed. The germanium tetrachloride extraction from products 1 and 2 were 78.50 and 19.52%, respectively. Such difference in indexes on extraction, is caused by germanium confinement as concomitant trace component to the basic phases to carriers. The share of acid-non-soluble compounds (tetragonal modification GeO2 and silikogermanaties) in the product 1 account for 21.5 % of germanium. Ratio between acid-soluble and acid-not -soluble germanium forms are 19.52 and 80.48 %, respectively, in the product 2. Our experiments have shown, that implementation of restorative firing (with addition of 30-40 % carbon at 1150 0?) of sulfide product 2 considerably impacted on the extraction of germanium tetrachloride (91.76 %) in comparison with its low enough extraction at straight distillation of hydrochloric acid (19.52 %). The results are confirmed by a set of physical methods. The results of processing the same so-called hard phase?s material (product 2) with the help of microorganisms are presented. It Has been established, that selected strains of bacteria are capable of extracting from initial raw materials not only macro components (iron, zinc, lead, manganese, aluminum, nickel), but also micro impurity of rare metals (gallium, germanium, zirconium). It is important that these metals were not extracted by traditional chemical methods (with application of aggressive conditions and heats) independently of the phase composition of the source. Almost complete extractions of germanium in solution using sulfur-oxidizing bacteria take place in the first day of the process independently of the phase composition of the source and the type strain. The results have practical significance and can be the basis for developing a unified biotechnological method of technogenic waste processing with a purpose of their sterilization and detoxification with simultaneous obtaining concentrates of valuable metals. Keywords: germanium, extraction, sublimates, bioleaching, sulfur-oxidizing bacteria.

Sep 1, 2012

By Tasuma Suzuki

Electrokinetic/permeable reactive barrier system is a promising in situ soil and ground water remediation technique to reduce toxic NO3- into less toxic NH4+. Using granular zero-valent iron (Fe0) as a reductant, the first objective of this study was to investigate the influence of the solid-liquid ratio and aqueouspHon NO3- reduction. The results obtained from a series of batch experiments showed that NO3- reduction was enhanced by either increasing solid-liquid ratio or decreasing aqueous pH. Based on insights obtained from batch experiments, the second objective of this study was set to design the remediation conditions of the electrokinetic/Fe0permeable reactive barrier system to maximize the NO3- reduction efficiency. Experimental results showed that the effectiveness of the system strongly depended on the Fe0 percentage in the reactive barrier, the pH in the anode reservoir, and the applied voltage, which were consistent with the results obtained from batch experiments. Under optimized treatment conditions, nearly 100 % NO3-was reduced into NH4+ in the permeable reactive barrier and collected in the cathode reservoir. Insights obtained from this study provided fundamental information on roles each of remediation design parameters plays, and will be useful to optimize the remediation conditions. Keywords: electrokinetic remediation, permeable reactive barrier, zero-valent iron, nitrate

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

By K. C. Corin

It is well known that the grinding circuit plays a crucial role in flotation. The effect of pulp chemistry during grinding is often overlooked. It is believed that the surface properties of the minerals can be adjusted during flotation rather than during grinding. However, recent development in surface analysis techniques (TOF-SIMS, XPS, and AES etc.) have proven that the hydrophilic iron hydroxides formed at the mineral surface during grinding make it difficult for collector adsorption, which may result in poor grades and recoveries of the valuable minerals. This study investigated the effect of the pulp chemistry conditions during milling and the subsequent effects on flotation performance of an Nkomati ore. The results have shown that there was approximately 10 % increase in Ni recovery, when the ore was ground at a dissolved oxygen (DO) concentration of 0 ppm (DO-0) in comparison to no gas control during the grinding stage. However, when the pH was changed from 9 to 11, no gas control resulted in a 20 % decrease in the Ni recovery compared to only 5 % decrease in the Ni recovery at DO-0. A noteworthy observation is that controlling a combination of DO and pH during grinding is of critical importance for better floatability and selectivity for such a system. It also became clear from this study that the presence of oxygen is critical to the consumption of xanthate, which is consistent with the general literature. It has been established that grinding at lower DO levels/redox potentials (Eh) in the presence of xanthate significantly improves the flotation performance of the valuable minerals.

Sep 1, 2012

By Vincent C. Smith, Agit Singh, Bernard Muller

The control of minerals processing plants is by no means trivial. In order to address some of the difficulties, it was decided to develop and test a model predictive controller (MPC) for a milling circuit. A milling simulator was written to test the MPC controller. Due to the large number of tuning parameters in a controller of this type, an optimising algorithm was written that automatically tunes the controller. Good, robust control was obtained when the controller was tuned using this algorithm. The controller was tested for various scenarios that are often encountered in the minerals processing industry. When problems were encountered, the MPC algorithm was specially adapted to accommodate for these difficulties. Control was further improved by using feedforward control as well as quadratic programming. The movement of the manipulated variables was reduced by using a region of uncertainty that allows the controlled variable to vary within a specified region around the setpoint. Integrators were handled by adapting the algorithm slightly and adding an optional integral error portion in the MPC controller. The performance of the enhanced MPC controller was compared to PI controllers on both the simulator and a commercial plant. The MPC controller showed faster responses with less interaction in both cases.

Jan 1, 2003

By E. V. Manlapig, M. C. Harris

"The complexity of the flotation process has made the identification of an appropriate model structure for the predictive simulation of flotation circuits far from obvious. Work performed under the auspices of the AMIRA P9 flotation program has indicated that the metallurgical performance achieved from a flotation cell arises from the interaction of two essentially independent property classes, namely the cell operating conditions and the properties of the cell feed stream. These observations have led to the development of a model structure that associates a constant set of flotation parameters to the streams of the circuit, which are transformed into a flotation response depending on the operating conditions within the flotation cell.A variety of alternative model structures exist within the literature which do not make this distinction between cell and stream flotation properties, and many of these models are in widespread use for flotation optimisation and design studies, both in industry and academia.In this paper, circuit survey and laboratory batch flotation data collected from an industrial flotation circuit are analysed. The data demonstrate that streams in an industrial flotation circuit exhibit varying particle floatability – concentrate streams typically float faster than tailing streams (Figure 1(a)). This floatability, however, is generally conserved around the various units within the flotation process (i.e. the effective floatability of the combined feed and product streams of a unit is equivalent (Figure 1(b)))."

Jan 1, 2003

By H. Araneda

Throughout Chile?s history, mining has consistently been a leading industry in the country. The 1990s marked the beginning of a boom in Chile?s mining industry, especially in copper mining, due to both foreign and local direct investment in the sector. Mining?s contribution to the GDP was 15.6% at current prices in 2009, and it accounts for 56% of the country?s exports. Chile?s copper market share reached 35% in 2009. The investment portfolio in mining in Chile for the coming decade has been estimated at 90 billion US dollars. The acute scarcity of human resources currently experienced by the mining sector in Chile will be accentuated in the coming decade as a result of this scenario of investments. The situation is, additionally, similar to the one confronted by other countries involved in the mining industry such as Australia, South Africa, Canada, and in Latin America includes, Peru, Colombia and Brazil. A study carried out by Fundacion Chile, ¨Labor Force in the Chile Mining Industry, Diagnostic and Recommendations, 2011-2020? shows the projected labor shortage for the operation of projects in the development stage, considering only the requirements of the process of extraction, processing, and maintenance. The demand, accumulated incrementally, will be around 115,000 technically skilled workers, professionals, and qualified workers. This figure refers to the operational work force, and does not include the human resources that will be required for the prior stage of the engineering and construction of the projects (brownfield and greenfield). The demand for technically skilled workers and professions for the stages of engineering and construction of the projects that have already received investments is estimated to be 190,000 people for the period 2012-2020. The peak of the demand for engineering is 2012, with a figure that surpasses the 12,000 professionals for all of the engineering specialties. The analysis of the formation of human resources at the tertiary level (where tertiary includes technical/vocational and academic degrees at the undergraduate level) for mining and related majors demonstrates that the programs are scarce with a bias toward theoretical contents and that they are excessively long (40% longer than comparable programs in Australia, Canada, and in OECD countries). The completion rates are low, especially in the technical-vocational programs, which have a completion rate of only around 30%. Finally, the rates of attraction of technically skilled labor and professionals towards careers in mining are insufficient to reduce the identified skill gaps. In the case of university professionals such as geologists, mining engineers and engineers in metallurgy, 80-90% will work in mining. In the case of graduates of relevant majors, that cover skills also utilized by other industries, not only mining?such as maintenance workers, operators of fixed and mobile equipment, etc.?the mining sector appears to be unattractive for reasons such as shift schedules, geographical location of work sites, and other factors. On the basis of the available diagnosis a strategy for the sector has been developed (Workforce Development and Skills Strategy) whose objective is (i) to define a Mining Qualifications Framework to identify the critical roles to be filled (ii) to start, with public resources, a ¨fast-track? training program to assure the availability of at least 28,000 operators (machinery operators, truck drivers, etc.) and maintenance specialists in 2015 (iii) to promote the development of training hubs for mining with learning technologies to train technical labor and professionals on the basis of world class standards (iv) to design and implement a campaign oriented toward the perception of mining as an attractive field of employment opportunity (v) to develop curricular innovations for tertiary education programs, on the basis of international benchmarks. Keynotes: Chile, mining, copper mining, skilled human resources

Sep 1, 2012

By E. Lee

Cone crushers are widely used within the mining and aggregate industries for the size reduction of minerals, ores, and rock materials. In mining applications for example, the product from cone crushers is often fed to HPGRs or directly to mills in the subsequent grinding circuit. An improved cone crusher performance can therefore result in an overall improved and more efficient comminution process. The objective of this paper is to systematically study a number of different ways of applying compressive crushing. By mathematically modelling these different crushing concepts and then theoretically optimizing crushing sequences accordingly, each concept can be studied and evaluated. In addition, aspects concerning whether or not the results are mechanically or practically achievable are considered. This study thus explores the advantages and disadvantages of different crushing concepts. In this paper, four different theoretical crushing concepts are presented and studied. The results show that in terms of interparticle crushing, optimal crushing sequences with varying compression ratios can be replaced by easier implemented series of constant compressions without significant deterioration. It is also shown that that considerably better performance is obtained for crushing sequences with both breakage modes. The subsequent comparison between such concepts indicates that different approaches can achieve the same results, and that the different concepts are comparable. It is further concluded that interparticle crushing should be kept to a minimum if fines generation or energy consumption is to be minimized, and that each of the studied concepts presents different challenges for implementation. Keywords: compressive crushing, cone crusher, optimization, modeling, crushing concept

Sep 1, 2012

By F. L. Mentg

The utilization of acid leaching tailings was studied. It is obvious that the Fe in acid leaching tailings can be leached into solutions as Fe2+. In this paper, the influence of conditions, including the concentration of ferrous sulfate, pH, temperature and velocity of air flow was investigated. The optimum conditions for preparing seed crystal are as follows: the concentration of ferrous sulfate is 20 g/L; pH is 9.5~10; reaction temperature is 10~20?; velocity of air flow is 0.4m3/h. The optimum conditions for preparing iron oxide red are as follows: the concentration of ferrous sulfate is 5 g/L; reaction temperature is 80~85?; velocity of air flow is 0.13m3/h. At last, the product of iron oxide red could be prepared by ammonia method.

Jan 1, 2014

By D. G. Hulbert

"Mineral processes are complex operations that have been modelled, controlled and simulated by diverse technologies. A review is given of some models of mineral processes in the literature. A new variation of a dynamic process model of flotation is presented. Process models, describing real and relevant physical variables, give a good understanding and good qualitative simulations, but can sometimes require prohibitively difficult and extensive parameter estimations. Process control is usually best done on operational plants by the fitting of system models, which can home in on the plant?s observability, controllability and optimisation. System models can be of a form amenable for use in appropriate techniques for controller design and implementation. The control of milling circuits is discussed in some detail. While simulators use models to predict dynamic or steady-state information, part of their strength lies in their ease of use and their ability to test different types of specifications. Some results are given for a flotation circuit simulator that can be made to solve virtually any permutation of specifications.INTRODUCTIONThe development and application of appropriate technology can lead to better operation of mineral processing plants in industry, so that substantial benefits can be obtained from improved throughputs, efficiencies and product qualities. This paper addresses some of the principles and methods used in the quest for the development and exploitation of such technology. Although the design of processes is often the motivation for modelling and simulation, this paper also targets the use of modelling and simulation for the control and optimum operation of mineral processes. The two processes given the most attention here are flotation and milling.Technologies used in mineral processing range from simple to very complex. Simple technical principles, such as mass and component balances, can yield some simple and effective strategies for modelling and control. However, minerals in particulate form have such complex physical and chemical properties that there appears no end to the complexity that emerges, as more and more factors are taken into consideration in the pursuit of better results and understanding. The situation is aggravated by the complexity of mineral processing plants, which have spatially variable conditions within process units, and complicated interactions between these units."

Jan 1, 2003

By Y. Y. Zhou

This paper introduces the application of CRIMM high-gradient magnetic separator in refinement of feldspar powders as well as the supporting technical outfits needed by the refining process with the high-gradient magnetic separator as main equipment. It could reduce the content of Fe2O3 to 0.03% with a deferrization rate of 85.88% from the feldspar raw ore containing 0.17% Fe2O3by using the above refining technology, producing an ultrapure feldspar product.

Jan 1, 2014

Spent automobile catalyst is an important secondary resource of PGMs (platinum group metals) and the recovery is significant. Various methods of recovery technology have been reported and applied in practical production, including pyro- and hydrometallurgical processes. Since the grade of PGMs in the catalysts is so low, approximately 0.5 wt. %, the present recycling technologies require high energy-consumption, it is of great significance to enrich the PGMs with some energy saving physical separation methods as a pretreatment. Automobile catalyst is usually composed of cordierite phase as a substrate and alumina phase, with PGMs, which covers the cordierite phase. We adopted the quenching pretreatment, one method of thermal shock, to generate micro-cracks between the two phases and separate the alumina phase from cordierite. Quenching was carried out by heating the catalysts in an electric furnace of different temperatures followed by rapid soaking into cold water. It was found that the phase boundary between alumina and cordierite was broken in the quenching and selective separation (detachment) of alumina from the cordierite could be achieved in the following surface grinding. The effect of quenching was checked by microscopic observation, hardness measurement, and chemical analysis. This paper figures out the stress formula of the quenching process, which is largely connected with layer thickness and temperature gradient by using an FEM (Finite Element Method) simulation and clarifies the mechanism of crack generation in the quenching process. Keywords: automobile catalyst, PGM, quenching process, FEM

Sep 1, 2012

By Komar Kawatra, Joseph Halt

"Bentonite clay has been the traditional binder for iron ore pellets. However, bentonite increases pellets’ silica contents and is expensive. Researchers have proposed lowering bentonite doses by mixing it with other common binders. These mixtures may only be successful if the fundamental bonding mechanisms are understood. For example, what happens when bentonite (physical bonding) is mixed with fly-ash (chemical bonding)? What happens when bentonite is mixed with cornstarch (physical bonding)? In this paper, experiments are described where bentonite was mixed with various ratios of cornstarch and fly-ash, and pellets were agglomerated using 0.66 % w/w binder. Ca(OH)2 and CaCl2 were added as activator and accelerator, respectively, to the bentonite-fly ash mixture. Curves of pellet dry strength vs. bentonite-starch ratio were linear, suggesting the physical-physical bonding mechanisms were compatible - acceptable strengths (> 22 N) were produced at all bentonite-to-starch ratios. This was contrary to bentonite-fly ash mixtures, which displayed dry strength curves with a noticeable minimum due to competing binding mechanisms. Bentonite alone and fly ash alone produced acceptable strengths (> 22 N), but their mixtures resulted in weak pellets. Due to the positive results using cornstarch (CS) binders, the effects of CS solubility in water were investigated using two CS with high and low solubility (60 and 7.5 %). CS was premixed with bentonite at various ratios (0, 20, 40, 60, 80, 100 %). Pellets were agglomerated using 0.66 % w/w binder. The dry strength of pellets ranged from 50-300 N using the high solubility CS mixtures, and from 50-85 N using the low solubility CS mixtures. Fired strengths exceeded 2200 N/pellet at all bentonite-cornstarch ratios. This research showed that cornstarch solubility is an important factor in determining its effectiveness as a binder for iron ore concentrates, but significant work is still necessary before it can be used as a bentonite replacement."

Jan 1, 2014

By C. Eswaraiah

A drop weight tester (DWT) is designed and fabricated for the purpose of analyzing single particle impact breakage characteristics of different ores. The test results were evaluated through the breakage distributions of different size fractions at five different input energy levels. The breakage parameter, t10 (Narayanan, 1986) is used to represent the degree of size reduction, which is assumed to be representative of the breakage product size distribution obtained from single particle breakage. Representation of breakage distribution with this method consist one more breakage dependent parameter (a). To evaluate the impact breakage characteristic of different ores, a mathematical relationship was established to analyze the dependency of breakage parameters, t10 and a on specific input energy (EIS) or fracture energy (Tavares et al, 1998, Fandrich, 1998), specimen size (?) and Bond?s operating work index (WI0). Mathematical results developed gives adequate model for all ball mill modeling. It can be concluded that the drop weight test method is a useful and practical way of evaluating the impact strengths of various ores and results of which can be used in modeling mills.

Sep 1, 2012