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By N. Djilali

Many of the transport phenomena encountered in proton exchange membrane fuel cells occur intrinsically at the microscale level. Physically representative models that fully account for the salient physico-chemical and transport processes in PEM fuel cells are necessary to achieve truly predictive models that can be used with confidence to: (i) gain a better understanding of in-situ processes and couplings, (ii) explore new concepts, and (iii) support design and optimization. The development of more general, rationally based macroscale models requires use of knowledge on the microscale level to provide guidance, and to determine the required parameters and coefficients (model "constants"). In this paper we present a new membrane transport model, the binary friction membrane model (BFM2), recently developed to account for coupled protonic and water transport in polymer membranes. This general model is based on rational and physical consideration, removes several of the limitations of the empirical models used to date, and is formulated for all purfluoro-sulfonic acid membranes. The use of the BFM2 in a fuel cell model is illustrated highlighting significant performance predictions compared to existing empirical model. The second part of the paper addresses the fundamentals of two-phase transport in hydrophobic gad diffusion media. Computational and experimental visualizations resolving the microscale dynamics of water transport between the fibres of a GDL are presented, revealing transport mechanisms that are, contrary to assumptions used to date, dominated by fingering and channeling.

Jan 1, 2005

By G. Riveros

A new, continuous fire refining process for copper has been developed and tested at the 5 tph pilot scale. During oxidation, the blister copper flows through a packed bed of crushed refractory bricks counter-current to a hot oxygen containing gas. The resulting desulphurized copper flows then directly into a packed bed of charcoal for deoxidation. By controlling the air to natural gas ratio, both temperature and reducing conditions can be controlled. Based on extensive laboratory scale measurements of the rate of copper oxidation and reduction, the process concept was developed aided by process modeling and simulation. The industrial-pilot scale installation built at the ENAMI Paipote smelter in Chile, consists of two cylindrical, compact reactors, operating in line, with a designed capacity of 5 t/h of blister copper. The results of the industrial-pilot tests confirmed the feasibility of the new process. The blister copper processing capacity was increased to 10 t/h with satisfactory sulphur removal. The degree of oxidation as well the copper temperature was controlled with relative ease. The specially designed siphon block allowed for smooth tapping of the oxidized copper and separation of refining slag. The reduction of oxidized copper in the packed bed of charcoal appeared to be very effective while control of the degree of reduction according to the height of the bed ensured control of the oxygen content in the refined copper at the required level.

Jan 1, 2007

By Dennis Martin

What is Borehole Hoisting Borehole Hoisting is the use of a hoisting plant to hoist rock, workers and materials or both, vertically through a borehole, between a mine level and surface or between two levels of an underground mine. Screen and bolt ground support on walls of 5.5 m diameter borehole hoisting shaft

May 1, 2013

By B. Das

"Computers have been used extensively in the mineral industry in exploration, reserves calculation, mining technology, mineral processing, etc. With respect to coal mining, there are also various applications for evaluating rock slope stability of open pits, design of open pits, underground operations, mine ventilation, ground control, data processing and management information, operations control and certain technological applications. Mine ventilation appears to be the field in underground coal mining touched on most; on the other hand, underground coal mining methods evaluation is represented only sparingly.It is therefore essential to review the status of the computer in underground coal mining methods evaluation in order to define its scope for further application. The paper discusses the roles of the mining engineer, programmer, computer operator and analyst as well as that of the computer. The important parameters will be identified and discussed along with their application for different underground coal mining methods, with their individual unit processes. Mainly, longwall face operations have been covered. Although many models have been of academic interest, they can be considered as important steps in a transition stage which will be followed by more practical applications for computers for underground coal mining method evaluations in the future. This calls for a coordinated effort from all concerned."

Jan 1, 1981

By Bhawani Singh, Mahendra Singh, N. K. C Samadhiya

"Inherently anisotropic rocks occur in abundance at many rock engineering project sites in Himalayan region. These rocks pose difficulty in analysis and design due to their direction dependent strength behaviour. Moreover the strength varies in a non-linear manner with confining pressure. Mohr- Coulomb strength criterion is widely used by geotechnical engineers for defining strength of rocks subjected to given confining pressure. However, the conventional Mohr-Coulomb (MC) criterion suffers from the limitation that the strength is treated to be linearly dependent on confining pressure. In the present article, the MC criterion has been modified by incorporating non-linear term while retaining the original parameters c and ?. The non-linearity with confining stress level has been imbibed through critical state concept (Barton, 1976). The criterion has been applied to a triaxial test data base comprising of more than 1140 triaxial tests conducted world-wide on anisotropic rocks. Statistical evaluation of the goodness of fit of the proposed criterion to the data-base has been carried out. Further the predictive capabilities have been evaluated by determining the error in estimation of triaxial strength if only few triaxial test data are available for determining the criterion parameters. The data base has also been back-analysed to assess the critical confining pressure for anisotropic rocks. Statistically the critical confining pressure, for the present criterion, may be taken nearly equal to 1.25?cmax, where ?cmax is the maximum value of the UCS out of all orientations of planes of anisotropy. It is concluded that reasonably good estimates of the anisotropic strength are possible through the proposed criterion.INTRODUCTIONMany rocks encountered in Himalayan region like shale, slate, schist and phyllite are inherently anisotropic and exhibit direction dependency in their strength behaviour. In addition, the strength of the rock also depends on the confining pressure and, the strength response is non-linear especially when the confining pressure may vary over large range. Conventionally, Mohr-Coulomb criterion is the most widely used criterion for rocks. However, the limitation of this criterion in its present form is that the strength is treated to be linearly dependent on the confining pressure. The present study attempts to address the following two main objectives: i) Include nonlinear response in the Mohr-Coulomb criterion while retaining parameters c and In their original form; and ii) consider anisotropic response of the rock for a given confining pressure. A nonlinear strength criterion, which uses shear strength parameters c and as per Mohr-Coulomb criterion, has been suggested based on critical state concept for rocks."

Jan 1, 2015

By Zorigtkhuu Davaanyam, Fisher Wang, Bern Klein, Amit Kumar

"The High Pressure Grinding Roll (HPGR) is an increasingly popular energy efficient solution for comminution of competent ore deposits that primarily competes with conventional crushers and tumbling mills. A significant barrier to increased adoption of HPGRs is the requirement for large amounts (one tonne or more) of sample for pilot testing which may not be feasible for most early staged projects.Various researchers have worked towards developing piston-die and JK drop weight tests to model and predict the energy requirements for an HPGR. Two small scale laboratory test procedures (the SMC test (Morrell, 2009) and the piston press tests (Davaanyam, 2015)) have been developed in recent years to provide necessary information to size an HPGR.These two methods were used to estimate the required specific energy for an HPGR unit and compared to HPGR pilot scale test results from a copper deposit. The comparison provides insight into the benefits and limitations of these tests.INTRODUCTIONHigh pressure grinding rolls (HPGR) have gained popularity in recent years because of their energy efficiency in comminution. Various researchers have suggested that approximately 50–80% of the total energy consumed in a mineral processing plant is used by the comminution equipment (Haque, 1999; Abouzeid & Fuerstenau, 2009; Wang, 2013). Haque (1999) showed that the efficiency of grinding equipment can be as low as 1%. Due to the energy intensive nature of comminution, mining industry has been forced to explore alternative energy efficient processes.An HPGR based circuit has been shown to be 10–25% more energy efficient than a conventional SABC circuit (Von Michaelis, 2009; Wang, 2013). A significant barrier to the increased adaptation of HPGRs is the requirement for a large amount of sample for pilot testing (up to 5 tons), even on a prefeasibility level. Numerous studies have been performed to utilize piston press test to analyze the performance of the HPGR circuit and to predict the energy consumption for an industrial application. This paper uses two small scale laboratory test procedures, the SMC test and a piston press test, to compare the energy requirement to the pilot HPGR data."

Jan 1, 2016

By Ian Sherrell, Michael Pirie, Riddhika Jain

"Conventionally, direct reduced iron (DRI) mixed with char from rotary furnace discharge is cooled down before separating the char via magnetic separator. The DRI must then be reheated for further downstream processing (i.e. smelting). Outotec has developed the PyroMagTM specifically to conserve thermal energy during this separation process. DRI is cleaned by feeding hot particles directly after reduction onto a rotating surface just above a stationary magnet assembly. This allows hot feeding of the clean DRI to the downstream equipment which renders the entire process more energy efficient.Continuous testing of the PyroMagTM was performed to verify design and separation. Because the use of DRI/char was not practical for test use, the pilot plant testing was conducted using a magnetite/sand mixture heated up to and beyond the Curie temperature of magnetite. The separation was efficient for both cold and hot processing with recoveries varying from 98.6% to 99.74%. As expected, the recoveries decreased to as low as 83.99% as the temperature was increased beyond the curie temperature of magnetite (585°C). Long term separation was thermally efficient and sustainable.INTRODUCTIONMagnetic drum separators are widely used in the mineral processing industry. These low to high intensity magnetic separators are used to concentrate various magnetic material, such as iron ore, and less magnetic materials, such as ilmenite and garnet from silica and other contaminantsThere are multiple classes of magnetism based on the effect that each material displays while in and out of a magnetic field. In a simplified fashion, which is more appropriate for mineral processing, the magnetic susceptibility of a mineral is used to define it as being ferromagnetic, paramagnetic or nonmagnetic. In this respect, minerals with varying degree of magnetic susceptibility can be selectively separated with different types of magnetic separation equipment in different stages of a process flow sheet. The lower strength magnets are employed early in the process to remove highly magnetic fractions. Later stages utilize greater magnetic fields for capture of less magnetically susceptible material."

Jan 1, 2016

By Feng Tianran, Lu Shijie, Shen Zhengchang, Han Zhibin, Tan Ming

"As a kind of non-metallic material, high-purify quartz sand has been widely used in many fields. Flotation is a popular way to process quartz sand. But it is in difficult position for flotation to get high-purify quartz product due to large amount of coarse particles contained in the feed. In this paper, a design principle of special flotation cell for high-purify quartz sand has been put forward base on ore property analysis and laboratory test, and the pilot scale special flotation cell has been developed to meet the requirement of the quartz sand flotation process. The special flotation cell for high-purify quartz sand is featured by middle positioned impeller, false bottom and draft tube, which could decrease the rising distance of mineralized bubble and strengthen the circulation capacity of the lower part of the flotation cell. Hydrodynamic study indicates that high air dispersion degree and strong lower slurry circulation could be produced by pilot scale special flotation cell, which is helpful to create a suitable hydrodynamic environment for quartz sand processing.INTRODUCTIONNatural quartz is a non-metallic mineral, which is widely used as raw material in multiple industry process (Shifu, 2006). High purity quartz, especially containing more than 99.9% silicon dioxide, is characterized by high temperature resistance, small thermal expansion coefficient, highly insulating and so on. The demand of high purity quartz has been rising along with social and economic development, now high purity quartz is widely used in the field of photovoltaic industry, electronic information, communications and aerospace industry.Quartz is a kind of main rocking-forming minerals in the nature. There are seven genetic types, such as natural crystal, quartz sandstone, quartzite, vein quartz, konilite, natural siliceous sand, granite quartz (Baolei, Shuilin, & Dianchao, 2012). The natural crystal is primarily used as raw material to refine high purity quartz, but it is not available for two reasons. On the one hand, the natural crystal is extremely expensive and poor in resources reserves, which can not satisfy the need of large-scale industrial production. On the other hand, the chemical component of natural crystal is instability, it may lead to low stable product performance in large industrial applications, and it is also difficult to achieve raw materials standardization. Therefore, there are a lot of studies to search for other technological methods to obtain high purity quartz from other genetic quartz types."

Jan 1, 2016

By R. Simard

"Conventional exploration strategies identify many mineral deposits as potentially interesting, although only a few of them turn out to be of economic importance. In the context of exploration for sulphide nickel deposits in the Canadian Shield, a decisional model, based on a statistical study of parameters relative to nickel deposits as well as to barren sulphide occurences, has been developed.Because such geophysical variables as gravimetry, aeromagnetism and topography could be related to the relative importance of nickel-bearing deposits, a statistical analysis of 13 such variables was carried out for 98 targets which were considered promising after conventional exploration. Among these 98 targets are36 sulphide nickel deposits in the Canadian Shield and 62 drill-tested non-economic occurrences. The results of this study led to the development of a linear logistic model that permits evaluation, for each of the targets, of the probability of finding a nickel deposit of potential commercial interest. This decisional model can thus complement conventional exploration strategies.RésuméLes stratégies conventionnelles d'exploration définissent un très grand nombre de cibles comportant un inténet minier potentiel dont seules quelques-unes correspondent à des gisements économiquement importants. Dans Ie cadre de l'exploration des dépôts nickélifères du Bouclier Canadien, nous avons défini un modelé de décision fonde sur l'étude statistique de divers paramètres relatifs tant aux gisements d'importance qu'aux cibles dites stériles.Ayant fait l'hypothèse que certaines variables géophysiques (gravimétrie, aéromagnétisme et topographie) peuvent suffire à fournir des indications sur l'importance relative d'un gisement nickélifère, nous avons entrepris l'analyse statistique de 13 variables évaluées sur un échantillon de 98 cibles considérées comme potentiellement intéressantes par les stratégies conventionnelles d'exploration. Ces 98 cibles se composent de 36 dépôt nickélifères d ‘importance recontrés sur tout Ie Bouclier Canadien et de 62 cibles stériles reconnues par forage. Nous avons défini à l'aide de ces données un modèle logistique linéaire. Ce dernier nous permet d'évaluer pour chacune des cibles les chances de trouver un gisement. Ce modèle de décision peut done s'inscrire comme outil complémentaire aux stratégies conventionnelles d ‘exploration."

Jan 1, 1980

By C. Chapman, P. Cowx

"INTRODUCTIONTetronics Research and Development Co. Limited has installed several plasma torches for steel heating in continuous caster tundishes. An extensive demonstration program on a 14 tonne tundish reported the following advantages of plasma heating.• close control of steel temperature to ± 5°C;• a reduction of the furnace tapping temperature of up to 20ºC, leading to savings in energy and refractories costs ;• improvement in steel quality, to produce a slab product with an equi-axed crystal structure and a reduced number of large sub-surface slag inclusions;• the virtual elimination of oxygen pickup in the tundish; and• the capability of making ferroalloy trim additions to the tundish to permit a change of steel grade during casting, greatly decreasing inventory costs.The Need for Tundish HeatingIn the continuous casting of steel, the function of the tundish is to transfer the molten metal between the ladle to one or more continuously fed casting moulds. Figure I shows a typical temperature profile of molten steel in the tundish over the first cast cycle. It is observed that a rapid drop in temperature occurs both at the start of the cast, due to the tundish refractories absorbing heat, and also during ladle changeover. In addition, as a result of thermal losses through the ladle sidewalls, there is a gradual decline in the bulk steel temperature over the entire heat cycle. Consequently, in normal tundish operation, it is necessary to cast with a high superheat (25°C to 30°C + above steel liquidus temperature) in order to prevent freeze-up of the strand. Problems of high temperature variation and the potential of the steel solidifying in the tundish are greater for small caster units of low thermal mass . A high steel superheat increases the steelmaking vessel process time and refractory wear and prevents the formation of a uniform equi-axed solidification structure in the cast steel, resulting in centre line segregation and porosity. The large drop in the casting temperature that occurs during unsteady state operation causes an increase in the number of sub-surface inclusions, reducing the value of the product. Accordingly, plasma heating may be employed to maintain the molten steel at an optimum temperature to produce a slab of consistent quality."

Jan 1, 1989

By Robin Perry, Claude Bazin

"Discrete transfer functions which use the grinding circuit feed tonnage to predict mass flowrates at reagent addition points in a flotation circuit were calibrated using a dynamic grinding/flotation circuit simulator. Predicted mass flow values are multiplied by reagent addition ratios to obtain actual reagent flow. The transfer functions are currently integrated into the distributed control system of Les Mines Selbaie.IntroductionThe development of adequate tools for the control of flotation processes is a continuous challenge. Since the early 1970s there have been numerous publications dealing with practical aspect of control of flotation processes. Most plants use a combination of feedback and feedforward controls to reduce the effect of the following flotation process disturbances (McKee, 1991):• changes in throughput;• changes in feed grade;• changes in particle floatability (size, liberation, surface oxidation ... ); and • deliberate changes of setpoint;Feedforward control manipulates variables such as reagent and/or air flow rate to attenuate the effect of disturbances such as changes of feed rate and mineral content. The feed forward strategy is driven by measurements of these disturbances. Feedback control is used to maintain process variables to targeted set-points of concentrate or tails grades. The feedback control action is driven by deviation from the set-point, caused by a deliberate change of set-point or disturbances.This paper proposes a method to improve feed forward control schemes by the addition of a simple model for solids transportation. The feedforward strategy considered in this paper is the ratio type, in which the manipulated variable is changed according to a predefmed ratio between this variable and the measured disturbance. A typical example is the ratio of the reagent addition to mass flow of ore.The paper reviews the state of the art in feed forward control strategy applied to flotation processes and describes the method used for predicting mass flow rates. The last section shows an application of the method in the Les Mines Selbaie flotation circuit."

Jan 1, 1994

By T. G. Joseph

ABSTRACT: The Canadian oil sands provide some of the harshest mining conditions in the world. Asoperations demand ever bigger tools, the toll on large mobile mining equipment is high, with structural life often half of that expected. Soft ground conditions predominantly lead to fatigue failure scenarios, poor stability, and inconsistent payload evaluations. These challenges are not solely a concern for Canadian oil sands mines; there are far-reaching implications for surface mining equipment in any poor ground-operating environment. This paper focuses on the basics of payload evaluation, motion response, and a simple estimate of structural life for haulers.

Jan 1, 2011

By W. F. J. Cosser

AN agreement having been arrived at in 1935 whereby McIntyre Porcupine Mines would purchase gravel for back-filling purposes from Hollinger Consolidated Gold Mines, the aerial gear as described below was installed. As originally discussed, the plan called for installation of a loading bin at the junction to the Hollinger tram, so making the McIntyre tram an entirely separate unit. The experience of the Hollinger engineers, however, went to prove that the operation of a bin (remote from sources of heat) should be avoided if possible, owing to the severe winter conditions (35° to 40° F. below zero).

Jan 1, 1938

By N. A. McPherson, P. C. Stevens, A. J. Rigby

"There has been a consistent move in recent years to continuously cast small billets while utilizing ceramic stream protection between tundish and mould. The need to have ceramic stream protection has developed from a need to improve billet surface quality by submerged pouring. The need to protect the ladle to tundish stream in conjunction with tundish to mould protection is explained.The continuous casting of thin slabs is at the development state and will require a great deal of ceramic development to ensure the economic viability of the project. An insight is given to the main problems.IntroductionDuring the early development period o f the continuous casting of steel in the late 1940s and 1950s, much of the work was carried out on small cross section products. For example, the continuous casting of 50 mm square billets was carried out on a production scale in the United Kingdom at Barrow. Slab casting was initiated on a production basis on 100 mm thick stainless steel slabs at Atlas Steel, Weiland, Ontario. In the case of slab casting the thickness increased gradually until it was similar to Slabbing Mill feedstock , i.e. in the range 200 mm to 250 mm , although stainless steel continued to be lower at around 185 mm thick.For billets , a significant proportion of steel is now cast at around 100 mm square which creates specific difficulties when casting with a submerged pour - mould powder practice. The move back to smaller cross sections is further emphasized by the current interest in "" Near Net Shape Casting"" . If this move continues, then significant development will be required to create the refractories used between tundish and mould in the continuous casting process.Two specific areas which will receive attention are; (I) the casting of small cross section billet s; and (2) the casting of thin slab."

Jan 1, 1990

By V. Panayotov, M. Panayotova

"Finding a reliable relationship between fundamental properties of minerals of non-ferrous metals and their ability to float is extremely important. The approach presented in this work allows us to draw predictive models for an effective flotation, suitable choice of reagents regime and expected technological results before the minerals enter the flotation process. Attempts to adjust the technological regime in already begun flotation are often unsuccessful because the basic physicochemical processes have already taken place. Mineral processing can be optimized on the basis of objective and basic parameters, decisive for the efficiency of the process - the state of the surface of the mineral; assessment of: minerals flotation ability, the need to apply and the type of needed pretreatment, and expected technological results. The theoretical foundations of such an approach are presented in the work, as well as supporting them experimental results, and information on practical implementation in lead-zinc and copper-pyrite ores selection.INTRODUCTIONIncreasing impoverishment of ores of nonferrous metals incoming to the flotation and rising costs for obtaining the final product lead to the inevitable question - will the mineral processing process be beneficial economically, technologically feasible and environmentally safe and what is the way to improve its efficiency. Some of the possible solutions are already in practice - new more efficient and less energy consuming flotation machines and equipment, new - more efficient and selective reagents, new combinations of flotation regimens, and so on.Finding a reliable relationship between fundamental properties of minerals of non-ferrous metals (sulphides and oxides - most of them with semiconductor properties) and their ability to float is extremely important. This is the subject of research, started in the 60s of the previous century and continuing to the present day. Such dependence would enable a realistic assessment of flotation ability (flotability) of minerals before their flotation processing. The basic dependence, displayed by the researchers as Hoberg (1975), Chanturia and Shafeev (1977), Chanturia and Lunin (1983), etc., represents a relationship between bulk properties of minerals and their flotability, considering especially the concentration of the main charge carriers, namely electrons or holes. The bulk properties are practically constant for minerals from a given field. But the 'main arena' of the flotation process is actually the mineral surface (Carta, 1970; Rao, Labonte, & Finch, 1992; Panayotov, 1999; Rao, 2003; Hu, Sun & Wang, 2010). Therefore, we introduce a methodology for studying the surface of minerals, which methodology gives the degree of semiconductor bands bending on the surface and respectively - the charge of the mineral surface and its ability to interact with reagent-collector. The latter can be used to select the most optimal reagent for the corresponding mineral."

Jan 1, 2016

By H. Ardehali, P. Lind

Many gold deposits also contain significant quantities of deleterious elements such as arsenic. Several biological pathways are possible for arsenic exposure; special care and caution must be used while undertaking metallurgical testwork on ores and concentrates that contain high levels of arsenic. Laboratory precautions pertaining to handling of airborne dust concentrations, necessary personal protective equipment, and effluent treatment are discussed.

Jan 1, 2014

By Alex Henderson

The underground hard rock mining industry has had little change since the mobile equipment era began in the 1970s. Equipment has become larger and faster but has not kept pace with the following challenges: ? Improvements in safe production, ? Increasing demand for metals, ? Environmental improvements, ? Decreasing grades, ? Increasing depth of mining, ? More metal from underground vs. surface mining, and ? Energy and green house gas awareness. We are on the cusp of a new mining era and must rethink how underground hard rock mining must change in order to meet these challenges. This paper will show historical changes and propose a set of guiding principles for the next era of mining. Mining has changed over the last century. Initially mining was primarily an endeavor carried on by private companies with minor environmental controls and few social expectations other than employment. In the mid to later part of the century the mining industry was facing new challenges: deeper mines, the London Metals Exchange markets for pricing, and environmental concerns related to acidic rock drainage coming to the forefront. In today?s context, mining has evolved in complexity with the social and environmental aspects equally or surpassing the technical complexities such as expanding from mining hard rock to laterites, and mining lower grades or at greater depths. Nowadays, communities must be considered as partners, both locally and globally and the increased international visibility pushes the mining sector to take a more balanced approach to the business of mining (Fig. 1).

May 1, 2011

By Kiran B. Chaudhuri, Michael Koch, Jorg Lema Patino

"Stricter pollution regulations together with other factors have stimulated interest in the modernization of the traditional sinter - blast-furnace lead operation. In this context, direct smelting methods have again come into prominence. Consequently, the Kivcet Lead Smelting Process, which belongs to this group, has attracted the attention of the lead producers of the world. The Kivcet Process offers the advantage that lead and zinc can be simultaneously recovered in a single furnace unit. KHD Humboldt Wedag A G, Koln, Federal Republic of Germany, has signed a contract with the Sociedad Complejo Metalurgico de Karachipampa of Bolivia for the delivery of a turn-key Kivcet plant, which is expected to be the first plant of its kind in commercial operation. This paper describes the design and expected operating data of the plant."

Jan 1, 1980

By A. Uribe-Salas, J. A. Finch, B. J. Huls

Froth depth or interface level is an important control variable in column flotation which can influence both grade and recovery. A common method of locating the level is based on sensing the hydrostatic pressure at one or more points along the column. The level indicated can be in considerable error, largely because of variations in froth and collection zone bulk densities. A portable conductivity probe has been developed to detect the position of the interface from conductance measurements across the interface. The location of the interface corresponds to the position where a large change in conductance is observed, which is primarily a consequence of the difference in gas holdup between the collection and froth zone. This probe detects the position of the interface to an accuracy of ± 5 cm. The probe can be used while the column is in operation, which allows for on-line recalibration of the level detection system. Results obtained in its application in a pilot-scale column (0.91 m in diameter) are described.

Jan 1, 1990

By R. E. Baylis, M. R. Tolley, S. Singh, A. J. Murray, R. Boden, L. E. Macaskie, T. P. Hathway, D. Vavlekas

We report rare earth element (REE) recovery using immobilized Serratia biofilm depositing metal phosphate via a robust enzymatic mechanism. Activity was approximately halved at pH 3.5 and restored at pH 5.5. REE(III) was recovered selectively against Th(IV) but the method was non-selective between different REEs (La, Y, Eu, Nd). Biofilms were active for a year (half life of ~ 3 months). The activity of aged biofilm was enhanced by pre-nucleation (‘priming’) with NdPO4 prior to onset of flow-through conditions. The use of different ‘priming’ metals and bacteria via a combinatorial approach revealed some REE selectivity through the selective exclusion of specific REEs.

Jan 1, 2014