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By H. Weissenbaeck, B. Nowak, M. Oesterreicher, R. Stastny

The producers of certain metals like nickel and cobalt increasingly face a shortage of easy-to-mine and easy-to-process ore bodies. Their focus is shifting towards alternative raw materials which in turn demand new, different extraction techniques. One potential route for processing a ferrous ore with a non-ferrous target metal is atmospheric leaching with hydrochloric acid followed by purification of the pregnant leach solution (PLS). For the separation of iron from the PLS, and, in turn, the extraction of the non-ferrous compounds, the following flow sheet is proposed. Pre-concentration of the PLS, oxidation of ferrous (if present) to ferric chloride, hydrolysis of ferric chloride leading to the precipitation of hematite and the evaporation of hydrochloric acid, followed by crystallization of non-hydrolysable metal chlorides by means of sparging hydrogen chloride into the solution. Hydrogen chloride required in the latter step is produced internally by super-azeotropic distillation of regenerated hydrochloric acid. The liquid filtrate from the crystallization step is recycled to hydrolysis. Depending on the specific composition of the PLS, the hematite produced contains only traces of other impurities, whereas the crystallized mix of non-hydrolysable metal chlorides – containing also the target metal in enriched form – contains ferric chloride only in an amount referring to the filter cake moisture. These crystals can then undergo further hydrometallurgical separation and extraction processes. As an example, this flow sheet is proposed for treating nickel laterite ores. Experiments related to the demonstration of crucial assumptions in the flow sheet are presented. Based on those experiments a mass and energy balance of the flow sheet was calculated and is presented here together with a table of the major consumables in order to provide a basis for an operating cost estimate and other process economics.

Jan 1, 2016

Presentation Plan Hoist ropes ?Importance ?Mandatory and routine Inspections Continuous monitoring of wire ropes for mine hoisting ?Why a continuous monitoring of mine hoisting ropes.? ?Description of the ??Contiscan?? monitoring system ?Information data gathering Advantages of the ??Contiscan?? monitoring system ?Visual rope inspection on daily basis ?Monthly inspection ?Payload capacity flexibility and potential increase for deep mining operations. ?Periodical inspections by external experts ?Importance of the costs associated with hoisting production shutdowns. Commercialization and availability

Aug 1, 2013

By Zhigao Xu, Ruan Chi, Zhenyue Zhang, Yaoyang Ruan, Zhengyan He

Thorium is frequently the main radioactive element in rare earth ores and is a resource that can potentially substitute for uranium. Thorium must be separated from rare earths in order to obtain products with low radioactivity. There are abundant resources of thorium in the rare earth ores in China, especially in Baiyunebo mixed ores. As an associated element coexisting in rare earth ores, thorium is, or can be, separated from rare earth concentrate, iron concentrate, as well as from waste water and slag to achieve recovery of thorium. The methods of separation include ion exchange resin, liquid-liquid extraction, and liquid-solid extraction. TBP extraction has been the main method applied to separate thorium by domestic and foreign scholars. This paper presents a comparison of different processes for the separation of thorium from rare earth ores, especially Baiyunebo mixed ores, single bastnaesite and monazite ore, and provides suggestions for the future recovery of thorium resources.

Jan 1, 2014

By O. Laitinen, M. Rudolph, J. A. Sirviö, H. Liimatainen, R. Hartmann, University of Oulu

The increasing complexity of the ores composition worldwide calls for suitable collectors with specific properties, such as selectivity, wettability, and in regard to current regulations, environmental sustainability. Therefore, collectors have to satisfy many features to improve the efficiency of flotation processes. Cellulose nanocrystals gain more and more interest due to the versatile synthesis routes which enable the integration of specific functional groups and components with different degrees of hydrophobicity within the molecular structure. Consequently, cellulose nanocrystals can be employed in flotation processes as depressant or collector molecules, respectively. Nonetheless, the usage of cellulose nanocrystals is still limited due to a lack of the characterization of nanocrystal-mineral interactions and the change of the surface wetting properties of minerals after adsorption phenomena between nanocrystals and minerals. In these studies, butyl-amine cellulose nanocrystal (BAC) and quartz are used as model system to investigate physicochemical properties of both, BAC and quartz, and examine the applicability of BAC in flotation processes. Therefore, the surface charge distribution and electrophoretic mobility of BAC and quartz are investigated and compared to understand the effect of electrostatic interactions between BACs, and BAC and quartz. Based on this, the adsorption of BAC on quartz is examined. Finally, microflotation experiments test the efficiency of BAC to be used in flotation processes. The flotation response is correlated to the specific surface charge of BAC revealing the dominant effect of surface charges on effective particle-bubble adhesions.

Jan 1, 2016

By Tiago Webber

Mineral resources estimation comprises basically two stages: (i) data collection, analysis and validation, and (ii) the estimate of the grades and tones of the deposit. The most applied method for sampling survey in mineral exploration is rotary drilling with total core recovery. High drilling costs make borehole geophysical logging attractive to obtain the maximum possible information from each borehole helping to understand ore intersections, grades variability, limits of the deposits and continuity of the mineralization. In this paper, borehole geophysical logging was used to enhance the sampling survey and to derive grades indirectly (without lab analysis) with a certain amount of uncertainty. Indicator kriging (IK) was the estimation method used, as it is adequate to incorporate the uncertainty associated with the geophysical derived grade values. The results were compared to the conventional procedures using grades determined via core analysis and ordinary kriging. Borehole geophysical logging proved to be efficient to define the essential features of ore deposit and IK provided results with acceptable precision and accuracy if compared to the model provided by ordinary kriging.

Oct 1, 2009

By Jochen Franke, Matt Bird, Thoma Perkins, Malcolm Powell, Jason Robertson, Paul Toor

zThe operation of SAG mills is variable over time due to their continually changing liner shape, mass and subsequent load motion. However, this tends to be poorly accommodated in liner design and mill control, with only limited compensation made for this influence, usually in the first few weeks after a new liner is installed. With ever-increasing ore competency, increasing energy costs and decreasing ore grades, simplified design and operational approaches that compromise the achievable mill efficiency are no longer adequate. This paper presents a methodology that has been developed to measure and account for the changes in mill performance as the liner wears. This involves monitoring all liner profiles – in other words the three-dimensional liner shape - over the life of the liner, then conducting controlled surveys at different stages of the liner wear life, and correlating the mill performance to the liner profiles. The measured liner mass is modelled to provide an ongoing meaningful load mass measure that excludes the liner mass.

Jan 1, 2012

By K. Poorhaydari, B. M. Patchett, D. G. Ivey

In this paper, some applications of carbon extraction replicas, as samples for transmission electron microscopy (TEM), are discussed. Modern high strength microalloyed (HSMA) steels, used as structural or pipeline materials, have very small grains with substructures. Replicas used in TEM can resolve the grain boundaries and can be used for grain size measurements in cases where the small size of the grains pushes the resolution of conventional optical microscopes. The grain size variations obtained from replicas correlated very well with mechanical property variations, indicated by hardness, in the fine-grained heat-affected zone and base metal of some welded HSMA steels. Replicas are also very suitable samples for precipitate examination with analytical TEM. Advantages and limitations of the application of replicas, as well as some corrections for the estimation of the volume fraction of fine precipitates, are discussed.

Jan 1, 2005

By H. Assadi, S. Reutzel, D. M. Herlach

Intermetallics exhibit unique solidification behaviour due to their chemical longrange order. This includes, for instance, generally slow solidification kinetics, and in some cases, an anomalous partitioning behaviour. In the present work the electromagnetic levitation technique - complemented by theoretical modelling - is used to explore various aspects of this behaviour, as observed in solidification of B2 phase in undercooled melts of the Ni-Al system. Moreover, a phase-field model is developed and used to illustrate the effect of chemical order on the solidification kinetics of a B2 phase in a model system. The phase-field model provides an additional basis for the simulation of solidification microstructures in intermetallic forming systems. Both experimental studies and theoretical work signify the role of chemical order in solidification of intermetallics.

Jan 1, 2006

By W. J. D. Stone

"INTRODUCTION Over the past decade, a number of publications have described the advances in High Intensity Wet Magnetic Separation. A number of significant, but small capacity installations were made and are successfully operating. These were followed some three years ago by larger installations treating ilmenite gravity concentrates; at least one machine treating 25 tons per hour of new feed was installed and is successfully operating.However, this still did not result in general acceptance that High Intensity Wet Magnetic Separation could be applied on a large scale. Neither did it dispel the feeling that High Intensity Wet Magnetic Separation was ""expensive"" and hence, confined to small scale – high value applications suchas the cleaning of tin concentrates. In addition, there is the usual reluctance of being the ""guinea pig"" which has resulted in waiting to see ""someone else"" make the first large installation decision. Such a decision and installation has now been made.Therefore, the purpose of this paper is to show that High Intensity Wet Magnetic Separation has been commercially accepted on a large scale and to show its general application to the base metal mineral industry.Examples are confined to a few specifics due to the large volume of preliminary test data that is available. The art has now reached the stage where much of the preliminary work should be taken through to serious evaluation."

Jan 1, 1971

By Curtis Rempel, John Bartlett, Alex Holtzapple

METSIM is a powerful program capable of modelling and simulating every known metallurgical and inorganic chemical process. METSIM is used by companies throughout the world to design, simulate and control operations from mine to tailings and everything in between. At its absolute simplest, METSIM can be used to create a process flowsheet. METSIM modules and built-in unit operations cover mass and energy balances for either steady-state or dynamic simulations of mine, stockpile, heap leach, material handling, comminution, beneficiation, hydrometallurgy, pyrometallurgy, gas and steam handling, and tailings management processes. Data for the material being processed can include mineralogy, particle size analysis, grade by size or multicomponent size analysis, washability data, mechanical, physical and thermodynamic properties. METSIM is written in APL (A Programming Language). Unlike C++, APL is simple and easy to learn, allowing the user to program whatever they can imagine, without first obtaining a degree in computer science. METSIM can also interface with EXCEL and other software through dynamic data exchange (DDE), allowing data to be imported and exported for viewing, analyzing and controlling. METSIM can answer simple or complex metallurgical and process questions allowing the user to predict and engineer without the issues of clumsy and tortuous spreadsheets.

Jan 1, 2014

By Y. Hou, E. Arinaitwe, L. Tong

A series of dense medium separation (DMS) tests were performed on four low-grade copper ores from Mount Polley mine in order to determine their amenability to pre-concentration. The tested ores contained disseminated sulphides, mostly chalcopyrite with low copper grades (0.15% - 0.2%) and relatively high iron grades (4.76% - 5.63%). The samples were screened into different size fractions ranging from 9.5 mm to 50.8 mm and DMS tests were performed on each size fraction at various separation densities. The pre-concentration efficiency at different size fractions and separation densities was evaluated in terms of metal upgrading and distribution. Mineralogical tests were also performed on selected DMS sink and float samples in order to understand the influence of mineralogy on the pre-concentration efficiency. The results showed that significant copper upgrading was achieved for intermediate size fractions only at the highest separation density tested. The copper recoveries generally increased with particle size at all separation densities. However, it was impossible to upgrade the copper content in the ores and achieve acceptable recoveries and mass rejections at the same time. Copper recoveries and grades showed a strong correlation with iron recoveries and grades indicating that it is possible to pre-concentrate copper by recovering magnetite and other iron-containing minerals in the ore. Overall, the results suggest that the optimum separation density and pre-concentration efficiency is a function of particle size, and that the ore mineralization properties limit the performance of DMS as a pre-concentration technology for such low-grade disseminated ores.

Jan 1, 2014

By J. W. Senn

A magnesium alloy modeled after commercial alloy WE54 was thermomechanically processed and characterized to understand the mechanisms by which its texture can be randomized, as reported by Ball and Prangnell [1]. Samples were deformed in plane strain compression to prescribed strain levels at temperatures high enough to prevent cracking and then recrystallized. The deformation texture is very similar to that observed after plane strain compression (e.g., rolling) of other Mg alloys, such as common AZ31. However, the texture can radically evolve during recrystallization. Annealing above the precipitate solvus temperature results in a nearly random recrystallization texture where the initially strong basal texture is completely eliminated. Annealing below the solvus temperature produces a recrystallized texture similar to conventional Mg alloys, i.e., a weakened basal texture. If this same material is then annealed above the solvus to promote grain growth, a randomized texture evolves, which is similar that of samples simply recrystallized above the solvus. It is hypothesized that a sort of preferred growth mechanism, whereby grains with random orientation grow faster than those with the original basal texture, contributes significantly to the texture randomization observed in wrought magnesium alloys containing rare earth elements.

Jan 1, 2006

By David Rahal, Saul Ortiz, Maria Escobedo

The general trend in the minerals industry is towards the processing of fine grained, disseminated mineral deposits. This has led to an increase in the number of fine/ultra-fine grinding installations using stirred media mills. The challenge is that both the equipment type and the mineralogy of the deposit have an effect on specific energy consumption. Fresnillo PLC recognized this issue and addressed it by providing samples for testing in a laboratory regrind system. The objective of the test program was to determine the specific energy required to achieve a product size of 10 µm (P80). A specific energy plot was generated for both a lead and zinc flotation concentrate. It indicated that 34 kWh/t and 51 kWh/t were required for the two samples (Pb and Zn respectively). This difference highlights the effect of mineralogy on the energy required for fine grinding. The regrind feed and products were submitted to a range of basic mineralogy tests to quantify the mineral differences that could have changed the specific energy requirements. These tests provided general mineralogy, documented optical textures, and provided particle size microscopy. The lead concentrate was found to contain significant amounts of silicates in addition to the dominant sulphide, pyrite. The zinc concentrate was determined to be mostly sphalerite with minor amounts of quartz, chalcopyrite, pyrite and galena. The material testing results illustrate the importance of basic mineralogy studies in conjunction with comminution testing to determine specific energy consumption.

Jan 1, 2016

By D. H. Wilson

"This paper examines the increasing need for mechanical-electrical people within the industry and some of the reasons why such a shortfall exists. It is suggested that, in part, it is image related. The present industry-education relationship in addressing the situation is examined and some thoughts are expressed on how these may be built on, in order to help solve the problem of attracting people to this critical area.IntroductionAs a long-time proponent of plant engineering and maintenance as a management function, I would like to review the progress made by the industry/ educational approaches in satisfying the needs in that area. In doing so, I would like to make the following points:1) that there has been an accelerating shortfall of mechanical-electrical people relative to the needs of the industry;2) that the condition will probably get worse before it gets better; ,3) that the past industry I educational approaches to alleviate the problem have met with limited success; and finally4) I would like to review some of the things being done and consider how these efforts might be extended."

Jan 1, 1981

By C. M. Acuna, M. Sherrington

In high temperature processes thermodynamic equilibrium is assumed and therefore chemical potential of elements, among the condensed phases, have to be the same. In such situation impurities distribute accordingly and their fractional distributions are affected by the masses of the coexisting phases. It has been claimed Teniente Converters perform quite well for smelting high impurity concentrates, especially in respect to volatilization and/or slagging. Production of high matte grade near white metal composition, requiring moderate oxygen enrichment in the process air, results in a huge mass of gas and therefore a high fraction of impurities report to it. Similarly, by recycling different sources of slag, flue dust or other materials, the mass of the final slag is increased and so do the masses of impurities reporting to the slag. Nevertheless, above a certain level the recycling of smelter byproducts is no longer feasible and the cycle has to be halted, unless higher impurity mattes are accepted. Although the process might be continued during converting and refining, lengthy and expensive measures have to be taken if suitable anode copper for electrolytic refining is to be achieved. In the present study samples of high arsenic matte grade and slag were obtained on a pilot scale. The matte samples, on the order 75%Cu, were equilibrated with slag at varying ratios in magnesia crucibles under CO/C02 atmospheres at 1523 K. After 24 hours equilibrium matte and slag were rapidly solidified and analyzed by copper, sulfur, iron and arsenic. Furthermore, industrial samples of matte and slag, in the order 75%Cu at 1523 K, were obtained via a special quenching sampling device to determine the association of copper and suspension of matte and copper in slag. Based on the results, the distribution coefficient of arsenic between slag and matte was evaluated along with copper species in slag and the fractional distribution of arsenic, in the coexisting phases, was determined as a function of the ratio mass of slag to mass of matte.

Jan 1, 2007

By A. J. Neale, B. C. Flintoff

"A review of the dynamic rod mill-ball mill grinding circuit simulator developed at the University of Alberta, highlighting the modular structure and open-ended design, demonstrates the ease with which classical feedback control strategies can be designed and implemented. Various open loop simulations are presented to demonstrate the highly interactive nature of the grinding circuit and to indicate where potential control problems may be encountered. Closed loop simulations are examined, beginning with the basic SISO classical feedback control of circuit product size. Further improvement in the grinding circuit performance in the presence of various disturbances is realized through the application of a classical MIMO feedback controller. As an example of advanced (multivariable) control, static decoupling is implemented and shown to provide additional improvement in overall circuit performance.INTRODUCTIONIt has long been recognized in the processing industries that a dynamic process simulator is an indispensable tool in the design and evaluation of automatic control schemes. In mineral processing the lack of these simulators is felt to have been a major hindrance to the widespread implementation of effective process control systems. In particular dynamic simulation is a necessary precursor to any study of modern (as opposed to classical) process control methods. This paper discusses the development of a dynamic simulator that can be used to study various feedback control strategies. The simulation software provides a powerful educational tool for those individuals interested in grinding circuit control."

Jan 1, 1988

By F. Rosenblum, P. Spira

"A correlation has been established between the oxygen demand of Brunswick Mining and Smelting ore and flotation results at the bench, pilot plant and operating plant scale. A method of dete""1llining the aeration requirement of sulphide ores on the basis of this correlation is presented. It is shown that abraded iron from grinding media plays an important role in aeration and flotation. Laboratory grinding must therefore be conducted under controlled conditions with suitable grinding media in order to obtain the true aeration requirement of the ore.A method of evaluating aerator efficiency, also based on oxygen demand measurements, has been used successfully at Brunswick Mining to design pilot plant and full-scale aeration systems.1. IntroductionPre-flotation aeration of sulphide pulps has been practiced in the Noranda Group for many years to help in the depression of pyrite and pyrrhotite and to promote chalcopyrite and/or galena. Recently, two out of three parallel circuits at the Brunswick Mining and Smelting Corp. Ltd. concentrator have been converted on a test basis to a new flowsheet incorporating aeration as a basic step. Among other benefits, a substantial decrease in the middlings load has been achieved as a result of improved pyrite rejection. There has been increasing interest in other organizations in the potential advantages to be derived from' aeration in terms of improved metallurgy and/or decreased reagent consumption."

Jan 1, 1978

By Donald Lindell

Safety Share ?Dad receives fryer for Christmas 2009 and makes delicious sweet potato fries ?When the oil fryer was pushed back on the stove for cooling, the back edge comes into contact with the stove top controls, unknowingly activating the cooking element, family leaves kitchen. ?Faint smell of smoke from the melting plastic alerted the family; teenager arrives first and pulls the fryer forward causing oil to spill onto hot stove and burst into flames that reach the microwave ?Teen runs for sink to grab pan of water but is stopped by Dad ?Dad opens refrigerator, grabs baking soda and pours it on fire, extinguishing flames Lessons 1.DO NOT USE WATER ON GREASE FIRE 2.Where is the baking soda in your kitchen?

May 1, 2010

By M. Connell, S. Bedrossian

Alkali cracking followed by chloride-based leaching is one of the prominent methods for rare earth element processing. Regeneration of the leach lixiviant, namely hydrochloric acid, is a critical operation in the process. A number of different process routes are available for recovery of hydrochloric acid from chloride solutions. The objective of this paper is to discuss various recovery routes and analyze the impact of several input variables on the variable operating cost.

Jan 1, 2014

By Charle Lawrence, Murray E. Blanchard

"A significant addition to Canada's commodity export transportation capabilities is being built by Ridley Terminals Inc. on Ridley Island in the Port of Prince Rupert on British Columbia's north coast.Site preparation began in early 1982. By the end of 1983 the terminal will be receiving coal from two major new mines being developed in B. C.'s massive $2.5 billion northeast coal development.The RTI terminal will have initial capacity to transfer 12 million tonnes of coal a year from railcars to storage and to ships. Capacity will be doubled to 24 million tonnes as market opportunities are developed.The challenge of building this $220-million facility in less than 24 months, the benefits Canada has received from the work the project is generating, and the long-term faith in Canada that this project represents, are all part of the excitement which surrounds the Ridley Terminal and northeast coal developments.RIDLEY TERMINALS INC. (RTI) is building a very significant addition to Canada's commodity export transportation capabilities. The facility, on Ridley Island at Prince Rupert, on the north coast of British Columbia, is a key link in British Columbia's northeast coal development which in itself is a massive undertaking involving investment of some $2.5 billion. The entire project is making a substantial contribution to Canada's economy at a time when such contributions are sorely needed.The development is creating employment, not only in British Columbia where its various parts are being created by mining companies, railways and others, but also across the country where suppliers are manufacturing a wide variety of good s and equipment for the development's participants.The RTI terminal is no exception. It is a critical cog in this mega project's large transportation system and its construction is contributing substantially to job creation and to other economic activity, in the Prince Rupert area and in many other parts of British Columbia and the rest of Canada."

Jan 1, 1983