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By M. Lahtinen

Traditionally, there have been three main methods for iron removal in the hydrometallurgical production of zinc. These methods are atmospheric precipitation of jarosite or goethite and pressurised precipitation of hematite. Jarosite precipitation is without doubt the leading and the most commonly used technology for iron removal. However, jarosite precipitation has some drawbacks, such as a low iron content (and, thus, high residue volume), high moisture content after filtration and often a high zinc content. These features make any environmentally acceptable way of using or disposing of jarosite more expensive, as compared to hematite and goethite. The importance of environmental regulations has grown in the zinc industry during the last decade, which will have an increasing effect on new investments. Hematite has several advantages over jarosite, such as a high iron content, low moisture and low zinc content. An important advantage of hematite is that it is suited for further use in the cement industry. However, until now the need for autoclave equipment has limited the spread and implementation of hematite precipitation in the zinc industry. Outokumpu Technology Oy has recently developed an alternative method for iron removal, which is the atmospheric precipitation of hematite. A patented method for precipitating hematite at atmospheric pressure is presented and compared with conventional methods for iron removal. The process conditions, the quality of the hematite precipitate and the environmental aspects are also discussed.

Jan 1, 2006

By Robert Bottge

When a company develops a mineral property in a remote area of Alaska, it must consider how best to house its personnel. This Bureau of Mines report examines the economics of two options: company towns and company camps. The price required to maintain a 15% discounted-cash-flow rate of return (DCFROR) was derived for hypothetical 1,000-st/d cut-and-fill mines and 50,000-st/d open-pit mines located in three different regions of the State, One set of hypothetical mines utilizes a townsite; the other utilizes a relatively new concept, a fly-in camp or commuting operation, in which two shifts of employees operate the mine and all associated facilities for 1 week before being replaced by a second crew. The study shows that operating costs were higher for mines employing the commuting option than for mines having a company town because of the additional wages paid for overtime hours; however, the price required to obtain a 15% DCFROR for the single-product copper concentrate, f.0.b. the mill site, was significantly lower owing to the lower investment costs for the camp-type operation. The economic advantage for those mines utilizing the camp increases from south to north and from the coast toward the interior.

Jan 1, 1986

By Arthur Laing

"IT is indeed a pleasure to have the opportunity of addressing this group today. Not only does it give me the opportunity of meeting with representatives of what is considered by many to be the most dynamic segment of industry in Canada today, but it also allows me to talk about a subject of para-mount interest to myself, the development of the North, and to explain, if even only briefly, some of our beliefs and hopes in this regard.It is inconceivable that all lands north of the 60th parallel, representing 35 per cent of Canada's total land area, which we believe contain a great natural resource potential, will remain as an undeveloped portion of Canada. The re-sources are there, although the people and private industry are as yet not there in sufficient numbers.It has been estimated that in the west and north of Canada there are 1.6 million cubic miles of sedimentary rocks. Of this figure, 342,-000 are thought to lie in Alberta, 115,000 in British Columbia and about 1 million cubic miles are thought to lie in Canada's northern regions, the bulk in the Arctic Islands. On the basis of apparent volumes of sedimentary rock, we estimate that as much as 13 billion barrels of petroleum may lie beneath the permafrost of the North-west Territories, another 3 billion barrels in the Yukon Territory and 33 billion barrels in the Arctic Islands. This is, indeed, a rich and elusive prize, and one which must be sought with a view to fulfilling demands on the production of petroleum."

Jan 1, 1966

By W. L. Uglow

In recent years, the microscope has come to be recognized as a valuable aid to engineers whose business is the discovery, development, concentration or reduction of metallic ores. In many of the large treatment plants microscopical research has already an important status; and in the hands of efficient operators the microscope has indicated methods of solving ore problems resulting in the saving of thousands of dollars that otherwise might have been lost in tailings, or expended in freight rates or smelter charges. Failure to procure all the information that the microscope can supply concerning the physical and mineralogical characteristics of complex ores has in many cases led to the construction of unsuitable concentrators, just as the failure to investigate in detail the geological conditions of an ore deposit has often results in the squandering of money on shaft sinking, and mechanical installations which subsequent development of the deposit failed to justify. The great progress recently made in the selective separation of minerals by means of the various processes of flotation and leaching brings strongly to our attention, the scope of the field in which microscopical methods may be advantageously employed. The microscope enables one to observe the minute details of rock, ore, gangue, concentrate, tailing, matte, slag and metal, that are invisible to the naked eye. Furthermore, the technique of microscopal research has been so highly developed that a microscopist can not only observe, but deter-mine the compositions and measure the diameters of the mineral constituents in the ore to be treated. Magnifications of these constituents up to 3,000 diameters may be produced by the proper combination of eyepiece, objective, and projection apparatus, and the images thus viewed may be photographed through the microscope, and permanent records made of them.

Jan 1, 1924

By Wallace E. Pratt

UNDER the stimulus of war psychology the American public has grown confused and jittery in its thinking on the subject of this nation's petroleum resources. This confusion arises from the failure of the average citizen, and even of many leaders in government, in our armed forces, and in the petroleum industry itself, to distinguish between our proved reserves of petroleum in the several oil-producing states and the total petroleum re- sources available to this nation. Leaders and public alike examine the accepted estimates of our proved reserves and thoughtlessly conclude that these estimates represent the total of our petroleum resources. Our fears are aggravated if we turn to the statistics on oil-finding and observe that the discovery of new reserves has waned decidedly in recent years. This confusion is dangerous because, under its influence, ill - considered policies spring up and flourish, choking out the most valuable fruits of the long experience of the American petroleum industry.

Jan 1, 1944

By A. H. Lang

"The name Barkc:rville district is applied loosely to the gold-bearing area around the historic town of Barkerville; the first mining camp in western Canada. The region is partly in the Cariboo mining division and partly in the Quesnel mining division. It contains two producing lode gold mines; the Cariboo Gold Quartz and the Island Mountain; and numerous other deposits. The regional structural pattern is outlined in this paper; the structural details of the producing mines are described in the papers that follow.The discovery of rich placer deposits in this district in 1860 was followed by the Cariboo gold rush. Placer mining in the area flourished until 1875 and then declined as the shallow diggings were exhausted, but important operations are still active. The total placer production amounts to about $50,000,000. An extraordinary number of quartz veins outcrop in the district, but many have only a small gold content. The miners soon recognized that the placer gold must have been derived from the erosion of these veins, and some directed their attention to the possibility of quartz mining. The erection of a 4stamp mill in 1876 was the first attempt at ore reduction in British Columbia, exclusive of arrastras. Efforts to mine the Cariboo lodes on a large scale were not successful, however, until 1933, when, due to the pertinacity of F. M. Wells and to the increased price of gold, the Cariboo Gold Quartz mine commenced production, followed by the Island Mountain mine in 1934. This success led to development work at many properties in the district, but the only ones that have reached production to date are the Columbia Tungstens, where scheelite has been mined intermittently since 1937, and the Cariboo Hudson, from which gold was produced in 1938 and 1939."

Jan 1, 1954

By Raúl Castro, Marco Vera, Alfonso Ovalle

The underground mining evolution for block cave mines in Chile and worldwide has made important strides in the last decades. Nonetheless, reserves determination in the initial stages of these types of projects—mainly for long-term planning—is not studied in as much detail as it should be, especially regarding the impact on the final value of the enterprise. Today, the first estimation of the size of a block cave mine, typically expressed in tons, tends to determine very large footprints and ore bodies. The resulting large-scale mine is obtained by applying the marginal cut-off grade (COG) to determine reserves. Yet, in many cases, it is possible to obtain an equal or higher benefit, extracting fewer reserves in less time, with a smaller active area, which significantly reduces the project’s uncertainty. To explore scenarios obtained by applying a higher marginal COG in the initial phases of the project, the Hill of Value methodology is used to estimate the net present value (NPV) in relation to the production rate and the COG. However, the application of this methodology considers certain simplifications that generate results which are not completely satisfactory in specific cases. This paper suggests an improvement of this method to obtain more reliable results regarding determination of a COG profile that will optimize the NPVof a block-cave project. The methodology was developed and applied in a massive polymetallic deposit with zinc, lead, and silver mineralization, corresponding to a real block caving project. The methodology provides NPV results that differ by approximately 15% in comparison to the real mine plan, while also being considerably simpler and faster to calculate. In summary, the proposed methodology provides a reasonable and fast procedure to estimate higher than marginal COG that increases the NPV of block cave mine projects.

By W. J. Taylor, T. D. Parris

"Over 90,000 feet of raise have been bored at International Nickel underground mining operations throughout the Sudbury District since the advent of raise boring in the early part of July, 1964. With a total of 10 raise borers on hand at this time, techniques have improved steadily since introduction at INCO mines. The first unit, designed for use in rock of low compressive strength, had to be modified and redesigned to cope with Sudbury Area Precambrian rock. As equipment and boring techniques improved, a specially designed machine for larger holes was developed and is now in use. More powerful units, with a thrust capacity of up to 750,000 pounds, are under investigation. Raises have been bored up to 84-inch diameter, and the changeover to 5- and 6-foot flat reaming heads with improved cutter design has increased performance substantially. As a result, 5-foot-diameter raises have been completed to a length of 750 feet and 6- and 7-foot raises to over 500 feet. Reference is also made to the drilling of over 23,000 feet of drainage and sand-fill holes, ranging up to 7% inches in diameter, with smaller underground rotary drill equipment.Finally, a look into the future indicates the need for further improvements in equipment design to permit economic boring of 7- to 8-foot-diameter raises in Sudbury Area ground types."

Jan 1, 1972

By Satish Kate

Indian limestone mines which are highly mechanized in operation and supply limestone to the cement plants have been quite successful in devising ways and means to optimize blasting parameters, so as to have best fragmentation, powder factor, and cost of excavation. In primary blasting mechanized or manually mixed ammonium nitrate Fuel Oil is quite popular in dry holes, and in case of watery holes conventional packaged slurry/emulsions are being used. In order to avail the low density characteristics of the ANFO, some limestone mines have also used Saw Dust and Rice Husk along with ANFO. A number of field trials have been undertaken to explore the suitability of mixing rice-husk and saw dust with ANFO. Presently, about 10% of rice husk/saw dust is being used only to expand the explosive column. The main technical consideration for the use of saw dust/rice husk, has been to reduce the final density and increase the occupancy of explosive in the blast-hole. This not only lowers the detonation pressure in the blast holes, but also reduces cost of explosive without compromising on the fragmentation quality. Besides, with sleeping of the charge there is no substantial fall in the blast quality.

Jan 1, 2006

By R. D. Mollison

"Ecstall Mining Limited was formed to operate the Kidd Creek mine, discovered by Texasgulf Incorporated in 1961 the orebody is geologically very complex, containing rich values of zinc, copper, silver and lead. The first phase of the operation involved an open pit, railroad and concentrator complex, which was under construction in 1965 and began operations in late 1966. The open pit, with rim dimensions of 2,000 by 1,000 feet, was computer-designed and highlights excellent wall control and efficient ore extraction and grade control. The railroad was built over the worst type of muskeg country, but it has been well maintained, resulting in an uninterrupted supply of ore in the trains. The 10,000-tpd concentrator, located 17 miles from the mine, is highly instrumented and automated. It features computer control of reagents and, in addition to the copper, zinc and lead flotation circuits, has a modern gravity tin plant. The concentrator is large, because very fine grinding is required for good metallurgy and nearly 2,500 tons per day of concentrates are produced. In 1969, work was started on the underground mine to take over from the open pit; it began partial production in mid-1973. The mine is highly instrumented, has a ramp from surface, a high-production shaft, an underground gyratory crusher and an efficient orehandling system, and employs the latest mining techniques. The electrolytic zine plant, rated at 120,000 tons of slab zinc per year, started operation in April, 1972, with batch leaching and purification circuits. It has been converted to continuous leaching and is now in the process of converting to continuous purification. Further modernization and automation will be carried out in the next few years. Five service departments support the five operating departments. These are maintenance, engineering and technical services, geology, administration and employee relations. How these ten departments function and work together using the most advanced technology to produce an efficient operation is the main theme of the Ecstall Story."

Jan 1, 1974

By Huw Williams

"Power companies are always looking to increase the carrying capacity of existing transmission lines, and the preferred method is to string heavier capacity conductor lines. However this results in higher wind loading and the potential for towers overturning, if the existing foundations do not have the tensile capacity. On older lines, there is often a lack of information on construction type and dimensions and in practice the as-built foundation can differ considerably from design drawings, due to unforeseen ground conditions along the line route, and no record of the resulting change in design being made.Following successful trials in New Zealand, integrity testing with Frequency Response and impedance profiling techniques is now being used in the region to check concrete foundation properties in-situ and are enabling power companies to get the most out of their assets. INTRODUCTIONIn most regions of the globe, the US included, there is generally a requirement to upgrade transmission line capacities, to cope with increasing power consumption. Problems with under capacity only come to light for the public when blackouts occur, even in developed countries.A large number of transmission line towers are designed with a certain capacity redundancy and will be able to carry greater loads than originally designed for. Power companies are therefore looking for ways to assess their assets and to minimize the costs of upgrade work.Re-assessment of tower foundation capacities using design drawings may not be valid , as constructed foundations may differ considerably from design drawings, to accommodate local difficulties and in some instanced, particularly with earlier lines, there is no information whatsoever. This complicates efforts to determine the capacity of foundations considerably."

Jan 1, 2005

By S Mitchell

Jetcrete Australia Pty Ltd, shotcrete contractor took the initiative in 2008 to discontinue the use of ‘road registerable’ concrete trucks for all underground works in Australia and internationally.The rationale for this decision was basic, safety. Historically these vehicles have been and still are involved in far too many accidents; this obvious trend needs to be addressed by engineering out the root cause of the problem which in this case is suitability for purpose.Road registerable concrete trucks have been widely used for the delivery of concrete in Australian mines for many years prior to and after the inception of wet shotcrete as ‘in cycle’ ground support in underground excavations around 1992. With this inception came a wide interest in the shotcrete process and an influx of new shotcrete contractors, all using road registerable concrete trucks to deliver the large volumes of Shotcrete required for these services and in turn largely increasing the use of these vehicles underground. The road registerable concrete trucks were difficult to control and each trip underground required the operators to maintain good management of the inherent risks. We virtually had no reasonable alternative for the industry and could only encourage the operators to drive with soft controls such as, reducing overall speed to a maximum of 15 km per hour when declining, regardless of the road conditions, coming to a complete halt prior to turning into any sharp corners, remaining in the same gear both inclining and declining.

Mar 21, 2011

By J. P. Morris

A diphenyl ether calorimeter for measuring high-temperature heat contents of ferrous alloys and iron-and steelmaking slags was constructed and calibrated with specimens of molybdenum, alumina, and platinum that were heated to temperatures ranging from 1,720° to 1,875° K. The standard deviation of the calibration measurements was 0.37 percent. By measurements of the enthalpy of delta and liquid iron, the heat of fusion of iron was found to be 3,298 ±100 cal per mole.

Jan 1, 1966

By G Gilchrist, S C. Dominy, T Jashashvili, R C. A Minnitt

The grouping and segregation error is one of Gy’s seven errors that cannot be measured in any qualitative manner because of its transient and changing characteristics each time the sample is handled mechanically. Attempts to calculate the mean and variance of the segregation error is considered by some as ‘an exercise in futility’ that would not help us achieve representative sampling. This research is aimed at understanding the process of segregation of dense, finely divided and dilute particulate materials supported in a clean quartz substrate during intense agitation. Several mixtures of fine-grained materials including steel, tungsten carbide and gold grains were used in these experiments. Four hundred grains of each of the minerals and metals at a top size of 2 mm were mixed with approximately 600 g of finely ground quartz material (95 per cent passing 2000 microns) in a 500 ml plastic jar with a sealable lid. The mineral–?metal mixtures were analysed in three steps using microfocus X-ray computed tomography. Step one consisted of rolling the containers on a flat surface in an attempt to concentrate the mineral and metal grains in the core of the supporting substrate; this is a base case that can be reconstructed after each session of analysis. The second step involved gentle and vigorous shaking of the mixtures in order to segregate the denser minerals and metals from the supporting quartz substrate. In some cases, a third step involved splitting the sample through a riffle splitter. Three-?dimensional images of the surface of each grain, its volume and its X-, Y- and Z-coordinates, before and after intense agitation of the container, were interpreted from the reconstruction of the tomographic X-ray data. The spatial analysis of grains using cell declustering and 3D variography provided a useful means of characterising the distribution of the grains in space and the extent to which they had become segregated during the process of agitation. Spatial analysis indicates that in general, grouping and continuity of grains is weakly developed. The modelled nugget effect remains high for most tests, indicating that grains of similar size did not group together strongly. Agitation through rolling provided the best continuity, although not consistently in the long axis of the plastic jar. The nugget effect was consistently highest, and the range of continuity shortest in samples that had been split, indicating that the grouping and continuity were reduced through splitting the sample. Initial results indicate that very little segregation of the minerals and metals occurs in the quartz substrate. This is somewhat counter-intuitive, but suggests that the effects of agitation on mixtures of dense minerals and metals in substrates of lower density do not lead to excessive segregation. Differences in behaviour between dense materials in response to agitation are evident. Grains of different composition and shape did not group and segregate in a predictable manner in response to the agitation methods. Initial results indicate that the degree to which a material groups and segregates relates more to the characteristics of the denser material itself, rather than the agitation method employed.CITATION:Minnitt, R C A, Jashashvili, T, Gilchrist, G and Dominy, S C, 2017. Quantifying segregation of minerals and metals in particulate materials using computed X-ray tomography and variography, in Proceedings Eighth World Conference on Sampling and Blending , pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Antony Amberg, Gonzalo Saldías, Romke Kuyvenhoven, Catherine Souza, Heriban Soto, Francisco Soto

"Vizcachitas is an advanced stage copper–molybdenum porphyry deposit, fully owned by Los Andes Copper and located in Central Chile. The property contains an indicated resource of 1,038 million tonnes grading 0.37% Cu and 0.012% Mo, and an inferred resource of 318 million tonnes grading 0.345% Cu and 0.013% Mo (Coffey & Alquimia, 2014). The deposit occurs in the same geological belt as several other giant copper-molybdenum porphyry deposits including Río Blanco-Los Bronces, Los Pelambres-Pachon and El Teniente. In 2018, the original Preliminary Economic Assessment (PEA) study from 2014 was updated; this paper presents the geometallurgical testwork that was performed to support that update. The testwork focused on the metallurgical characterization of 40 DDH samples and the development of a more profound orebody knowledge by relating geological features with metallurgical performance. The scope of work included complete chemical and mineralogical QemSCAN characterization; SAG, ball mill and abrasion testing; complete rougher and cleaner kinetics including locked-cycle-test; environmental ABA and settling tests on rougher tailings. The results show that the ore can be classified as medium-hard, with a hardness that is slightly below the average for large Cu/Mo deposits in the region. A good correlation was found between lithology and breakage characteristics, implying that the specific energy consumption (kWh/t) is well correlated to rock type. The results of the flotation tests were very encouraging and did not show significant variability. An overall Cu recovery of 91% can be expected for the flotation circuit. The use of a relatively coarse primary grind size gave good final recovery and grade for both Cu and Mo, and deserves further attention in future work, as this impacts positively both energy consumption and water recovery.INTRODUCTION Los Andes Copper Ltd. is a Canadian exploration and development company focused on the acquisition, exploration and development of advanced stage copper deposits in Latin America. The company owns 100% of the Vizcachitas project in Chile, the largest copper deposit in the Americas not controlled by the majors. Vizcachitas is a copper-molybdenum porphyry deposit, located 120 km north of Santiago, in an area of very good infrastructure."

Jan 1, 2018

By J Player, G Sweby, S Webber, E Jones

Seismic systems are a tool for the monitoring and forecasting the rock mass response to excavation. Common issues encountered at mine site audits and reviews are: how to design an effective seismic system, implementation of the design, interpretation of seismic source results and understanding the reliability of the seismic source. These issues are often a function of several items including: • Experience of site personnel in undertaking seismic system design. • Personnel not envisioning multiple phases of system expansion to understand system robustness issues. • System design/expansion occurring in response to damaging seismic activity rather than planned expansion of a system • The mine access development is often localised in comparison to the total orebody being mined hence, planning sensors in longholes in advance of development rather than in short holes close to development will improve the three-dimensional aspect of the network. • Limited site processing of the seismic event data, hence engineers do not see the uncertainty associated with event location, size, source and system layout. Mine site users require a framework to appreciate the challenges and limitations in locating large events. For example, event locations are given as precise measurements (to the nearest centimetre) whereas the volume of deformation resulting in the event often has dimensions of tens of metres or more (as defined by the source radius). A stronger awareness of the uncertainty of rock mass yield within large seismic sources will assist site users in the interpretation of rock mass damage. The encountered design and implementation errors are reviewed and discussed with a practical set of rules presented to provide a robust seismic system that provides consistent results and increases the user’s understanding of uncertainty in source location and size. The authors’ experience across multiple mine sites, seismic systems and damaging seismic events over a 30 year period has been summarised into practical rules for site personnel of all experience levels.

Nov 29, 2022

By T. A. Rickard

A severely technical article, however well written, can not be an agreeable form of literature. It suffers from the defects of its qualities. One defect is a congestion of language, due to a multiplicity of adjectival nouns. The sentences are packed with words of unpleasing sound, charged with complex ideas, crowding one another so closely that the phraseology moves like an ice-pack in Bering Sea or a log-drive in a river; the undercurrent of meaning may continue to move, but the surface is obstructed. This verbal congestion is made evident by ugly compoundings, many of which are adopted by the technical writer in the mistaken belief that they give directness to his statements. For example: A unanimously approved scheme "A scheme unanimously approved" The continuous temperature record "The continuous record of temperature" To stimulate interest in synthetic plant construction "To stimulate interest in the construction of synthetic plants " In smelters reverberatory-furnace firing with powdered coal has been practised for a decade. "In smelting, the firing of reverberatory furnaces with powdered coal has been practised for a decade. " A tar consumption of one pound per ton "A consumption of tar at the rate of one pound per ton'

Jan 1, 1931

By K. G. Chipman

The Geological Survey is the oldest map making department in the Canadian Government service, and when organized in 1842, one of the first principles to be recognized was the absolute necessity of having good maps. The primary purpose of the Survey has always been geology; but because a graphic representation by means of maps makes the written report .more readily intelligible; because the correlation of known geological facts is often difficult or nearly impossible unless they can be represented on a map; and, because the public demand information shown in this way, the Geological Survey must continue to supply maps; and the supplying of these maps must be considered as an essential part of the work of the Survey. It is a commonly recognized principle of pedagogics that an appeal to the eye is quicker than one to the ear; that children (and others) learn more quickly when a thing is presented to them through the eye rather than through the ear. The application of this principle to the work of the Geological Survey is that, to a large number of people, the message of a map is more quickly grasped, is more readily intelligible, and is in many ways of more interest and value than is the same information in a report. I do not mean that the maps are of more importance than the reports.

Jan 1, 1924

By O Arafat, K M. Bartholomew

A voracious consumer of energy and grinding media, the modern ball milling circuit has a huge direct cost impact on a mineral processing operation. Through optimisation, grinding also has the potential to unlock great improvements in recovery and throughput, but how can the complex interactions between mills, classifiers, tonnage, ore-type and downstream recovery be measured, understood and managed in a systematic manner?Functional performance analysis provides the tools and insights needed to measure, understand and improve the two key process efficiencies in ball milling circuits: classification system efficiency (CSE) and mill grinding efficiency.CSE measures the composite performance of the classification system as a whole. In short, the purpose of the classification system is to ensure that grinding mill energy is used to grind coarse particles while minimising overgrinding. CSE is simple to measure in the plant and it provides immediate feedback to the plant metallurgist, mill superintendent and management about the performance of the classification system and the amount of wasted energy in the grinding plant.Mill grinding efficiency measures the capacity of the grinding mill to convert feed-sized material into product-sized material on a tonnes per kilowatt hour basis. It is normalised based upon the ore resistance to breakage, so it provides feedback about the ‘health’ of the milling process under varying operating conditions and ore types. Mill grinding efficiency is measured at the same time as CSE through circuit sampling.Functional performance analysis combines CSE and mill grinding efficiency to provide a measureable, manageable optimisation objective. It also provides a link to tonnage, ore type and recovery. As a result, systematic optimisation of a grinding circuit is a measureable and manageable process to meet business objectives.CITATION:Bartholomew, K M, McIvor, R E and Arafat, O, 2014. Functional performance of ball milling circuits – a plant metallurgist’s tool for process characterisation and optimisation, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 227–232 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By W. J. Dolinar

The U.S. Bureau of Mines implemented the Fe2+ /Fe3+-SO2 anode reaction in a Cu electrowinning cell with full-size electrodes. Electrowinning was conducted using industrial electrolyte at 258 A/m2 (24 A/ft2) and 40 'C. Manifold injection of electrolyte provided circulation between the electrodes. Five-day operation using an optimized manifold gave an average cell voltage of 0.94 V at 89% current efficiency, which amounted to an energy savings of 2.82 MJ/kg (0.355 kW-hr/lb) compared to conventional electrowinning. Acid misting was completely eliminated, and SO2 concentration 23 cm (9 in.) above the cell averaged 0.06 ppm.

Jan 1, 1995