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By A. K. Croteau

"At Craigmont Mines Limited, Merritt, B.C., the mining practice of trackless sub-level caving was started in the latter part of 1966. This type of mining was new to the mine personnel and the mining industry of Canada as a whole. Sub-level caving has presented many old and a number of new problems in maintaining the equipment used in this method. This paper will deal with some of these problems as they affect this particular mining operation. It will be impossible to review all phases of the equipment, but an attempt will be made to cover the most pertinent aspects in maintaining the drilling, mucking and hauling, and auxiliary equipment."

Jan 1, 1970

By Stephen Hammond

?Our own prejudices form the greatest barrier to creating an inclusive working environment.? Have you witnessed? Racism or Negative Comments about an Aboriginal Person? ?You are free to compete with all the others?, and still justly believe that you have been completely fair.? Lyndon B. Johnson

May 1, 2008

By E. E. Mason

THE Myrtle group of mining claims is situated on Barkerville mountain in the Cariboo mining district of British Columbia, west of the old mining town of Barkerville. An 1,800-foot adit, known as the Shamrock tunnel, was driven in 1935-36 from the Barkerville road and in the general direction of the Myrtle group. It was proposed to enlarge this adit to more convenient section, extend it 2,500 feet int0 Myrtle ground, and from there drive a main entry 3,000 feet along the length of the group. Several laterals were also to be driven off this main entry as part of the tunnel schedule. It was thus originally proposed to drive 5,500 feet of new adit and 1,800 feet of laterals, a total of 7,300 feet of new work. Work was commenced with a bulldozer on April 21st, 1941, cutting a bench on the hillside for a plant site. The power plant was ready for operation on August 8th. Slashing and re-timbering of the old adit rook longer than was expected. It was found that 57 per cent of the length required timbering, chiefly by fore-poling, and there was also trouble in several sections with swelling ground. First round in the new face was taken on September 17th, when a 2-shift daily schedule was commenced. Due to delays in delivery of electrical equipment, it was not possible to add the third shift until November 14th. From then on, a 3-shift daily schedule was maintained with the exception of holidays and fortnightly change Sundays until August 1st, 1942, when shortage of labour caused the dropping of a shift. All work was suspended on August 14th. The ground through which the tunnel passed was such that the driving was often interrupted by the need of protective timber at the face. Further, crews were continuously employed timbering behind the face, and in maintenance of timbered sections in swelling ground. Roughly 980 feet of the new workings are now timbered, about 21 per cent of the total.

Jan 1, 1942

By J. P. Grau, J. Z. Lu

"Thickeners/clarifiers are widely used in coal preparation plants, potash processing and other mineral processing facilities. Thickeners play a very important role in slurry treatment systems to accomplish solid/liquid separation. The demand for larger plants and the increased thickener handling capacities sometime require thickener diameters as large as 200m. The development and use of high capacity thickeners makes it possible to increase the handling capacity of these thickeners by several to more than 10 times compared to conventional thickeners. Hence, for a given slurry rate, selection of a high capacity thickener will significantly reduce the footprint of the thickener. Much higher handling rate, higher concentration of underflow, clearer overflow and lower capital cost are obvious advantages of high capacity thickeners; however, some process requirements and the concerns of operational cost, especially the flocculant cost of a high capacity thickener operation, keep some engineers selecting conventional thickeners and staying away from the high capacity thickeners. Forty years after the first high capacity thickener was developed, there are still arguments in the selection of conventional thickeners or high capacity thickeners in mineral processing. The arguments will continue unless there is a clear picture of capital cost vs. operational cost for each of the thickener types. The purpose of this paper is to analyze these costs and to provide guidelines for selection of thickeners. INTRODUCTIONThickeners/clarifiers are widely used in various slurry treatment systems. For mining and mineral processing, thickeners are an integral part of the solid/liquid separation system. The feed to the thickeners are processing slurries. The fundamental mechanism for the solids/liquid separation is for the solid particles in the slurry to gravity settle inside the thickener tank. The clear water overflows from the top of the thickener tank and is typically reused in the processing circuit, and the concentrated underflow is discharged to different downstream process systems depending on the application of the thickeners. The general requirements for a thickener operation include high density of underflow and clear overflow. Since thickener operation consists of continuous feeding, overflow and discharge of underflow, the solid particles will gravity settle against an upward flow with its velocity dependent on the feed rate and the underflow discharge rate. Higher feed rates to a given thickener produce higher upward velocities. Underflow discharge is typically relatively small compared to the amount of overflow. The upward flow tends to take particles up to the overflow. Only those particles having a settling velocity greater than the upward flow velocity will possibly settle out. Hence, thickener feed rate has to be controlled so that the required overflow water clarity can be achieved."

Jan 1, 2012

By D. Imeson, T. Grammatikopoulos, G. Pearse, M. Aghamirian, C. Mohns

"Spodumene mineral is a source of lithium for lithium ion batteries. Thus, the production of a spodumene concentrate with an approximate grade of 6% Li2O is targeted. Traditionally, spodumene is concentrated by froth flotation using fatty acid as the collector. Amine collector can also be used to float mica ahead of spodumene as required or feldspar from the spodumene tailings. Slimes have a negative effect on spodumene flotation and they are commonly separated by scrubbing and de-sliming prior to spodumene flotation. The main losses in spodumene flotation typically occur in cyclone overflow, scrubbing slimes, spodumene flotation tailings and mica concentrate. In recent years, dense media separation (DMS) is the main concentrating process in Australian spodumene operations. In these operations, DMS is efficient at generating coarse grain concentrates and rejecting large portions of silicate gangue, thereby directly reducing the milling cost. The ore should be crushed to 3/8” or coarser while further crushing is possibly necessary on the middling particles to scalp further spodumene. The DMS feed should be classified to remove fines (typically -0.5 mm particles). The final middlings and undersize fractions could then be processed by flotation. The main requirement in DMS operations is to have good spodumene liberation at relatively large grain size. This paper reviews the most significant DMS and flotation parameters in spodumene beneficiation. The treatments of different minerals in the spodumene ore are also addressed.INTRODUCTION A number of laboratory/pilot plant programs have been recently conducted at the SGS Lakefield site, sponsored by different clients. The main objective has been to develop a process flowsheet to generate a spodumene concentrate containing 6.0% or higher Li2O (~75% spodumene) suitable for producing lithium carbonate by a hydrometallurgical process. Depending on spodumene liberation size, dense media separation (DMS) can be an attractive option to produce a final high grade concentrate and to reduce the mass to be treated in the flotation circuit. In such a case, crushing would typically be performed in stages, with DMS separation to recover a spodumene concentrate and reject gangue minerals following each stage. DMS middlings and -0.5 mm fines can be processed by flotation to further recover spodumene. In the flotation process, coarse stage grinding minimizes the grinding cost and formation of slimes. In the majority of cases, a grind size (K80) of approximately 200 microns is sufficient for flotation. After primary grinding, mica, if present in an appreciable amount, should be floated to minimize interference with spodumene flotation. Desliming after scrubbing and high density conditioning are the key process operations prior to spodumene flotation. Spodumene can then be floated from silicate gangue minerals with a fatty acid or a mixture of fatty acid and petroleum sulfonate at slightly alkaline pH. Subsequently, feldspars can then be floated from the spodumene tailings."

Jan 1, 2012

By Ho-Sung Yoon, Jyothi Rajesh Kumar, Chul-Joo Kim, Sung-Don Kim

A recovery process for rare earths (REs) such as dysprosium and neodymium from the leach liquor of permanent magnet scrap (PMS) was developed. The two hydrometallurgical routes namely liquid-liquid extraction (solvent extraction) and selective stripping were implemented. The present study deals with the separation and recovery process development by using organo-phosphorous based extractant di-(2-ethylhexyl phosphoric acid (D2EHPA) as reagent for REs processing. Initial studies considered the influence of time on the extraction process, as well as pH and extractant concentration effects. This suggested the aqueous mechanism and separation factors played a role in process during development. McCabe-Thiele diagrams for extraction isotherms were developed. Counter current extraction (CCE) using various phase ratios influenced metals separation. Maximum loading capacity of the D2EHPA was determined. The loaded organic generated by the CCE process was water washed followed by a scrubbing process to remove the other metal ion from targeted metal. Finally, a stripping process was tested using various mineral acids.

Jan 1, 2015

By V. D. del Valle, T. G. Joseph, J. J. Berezan

Aggressive driving patterns, rough and poorly maintained roads and pit floors, along with the occasional bump and poorly placed load from a shovel can create intense and sometimes serious vibration levels on a heavy hauler. The effects of high vibration have been shown to be of concern for the health of the operator as well as the reliability of the equipment. It is proposed that an onboard vibration warning system based on the ISO 2631-1 standard could be used to help operators reduce the vibration levels experienced in a heavy hauler. The onboard system would consist of a screen that displays the instantaneous vibration in the form of three lights: green (safe zone), yellow (cautious zone), and red (danger zone), as well as an overall vibration exposure or dose for the entire shift. With the utilization of the warning system, it is anticipated that the overall vibration levels will be decreased resulting in improved operator health, a reduction of vibration-induced maintenance, and improved haul roads through reduced impact loading and repair for localized trouble areas.

Jan 1, 2004

By Shen Zhengchang, Dong Ganguo, Chen Dong, Zhang Ming

"It is advantageous to process low grade ores with large scale flotation cells. Large-scale flotation cells have been enhanced with effective volume scale-up. In this paper, the latest and largest flotation cell with effective volume of 680 m3 in China is investigated. The hydrodynamics and flotation kinetics characteristics are conducted using CFD simulation. The similar circulating flow is formed compared to the previous BGRIMM (Beijing General Research Institute of Mining and Metallurgy) flotation cell and it is a suitable fluid dynamics environment. It is demonstrated that the flotation cell produces good gas dispersion and solid suspension. It is indicated that kinetic eddy dissipation plays a key role on collision kernel and collision probability profile. The higher collision probability profile appears at the impeller and stator regions aiding good metallurgical performances. The properties of the large-scale flotation cell are assessed using hydrodynamic numbers. The variation of hydrodynamic numbers such as the power number Np, the Froude number Fr, the air flow number Na, etc with flotation cell volumes show similar properties to previous flotation cells proven to be good in engineering applications. This research would aid structure optimization of the 680 m3 flotation cell.INTRODUCTIONFroth flotation is one of the mains method used in the mineral industry, which is used to process the most of metallic minerals. The proportion of low grade ores has increased with the minerals exploited around world. The increased capacity of concentrators demands large-scale flotation cells. Therefore, flotation equipment has seen a significant increase in size, for which large-scale flotation cells have prominent advantages in improving metallurgical performances, reducing area of plant blueprint printer, lowering the power consumption of the unit ore, decreasing labor cost and overall capital cost. Since the end of 1940’s, flotation cell sizes have continuously increased. To the end of 1990’s, flotation cells with the effective volume of 200 m3 were developed. In the last two decades, flotation cells have achieved a dramatic increase in size. In 2003, an industrial experiment on 257 m3 Smart Cell flotation cells was carried out in Minera Los-Pelambres, Chile. In 2007, the first 300 m3 Tank Cell flotation cell was designed and obtained industrial application in Macraes gold ore, New Zealand. And 320 m3 BGRIMM flotation cells are also in good operation in Toromocho Copper Mine, Peru and Wunugetushan Copper Mine, China. However, flotation cells are conventionally designed using empirically derived relations and geometric similarity. The continual scale-up of flotation cells is still a significant developing process. A 500 m3 Tank Cell was designed for the industrial experiment in Finland and a 620 m3 Tank Cell have also been completed the design. A 660 m3 Super Cell also was manufactured for the industrial experiment released in IMPC 2014. So, the flotation cells with volume exceeding 600 m3 become a pioneering research field for researchers worldwide."

Jan 1, 2016

"The application of telerobotics to mining is currently being introduced into production systems around the world. Mining companies in Canada, Sweden, South Africa, and Australia have tended to lead the international charge to this form of technology for mining. While this introduction is taking place, a few basic questions have yet to be answered. How many machines can a single operator run? How many types of machines can a single operator run?A Canadian Research Chair in Robotics and Mine Automation has been established at Laurentian University to investigate these questions and many more through a series of experiments in a telerobotics laboratory that connects Laurentian teleoperation workstations to model mining machines at Cambrian College’s eDome. The laboratory supports many experiments allowing researchers to physically run multiple robot scenarios differing the numbers and types of machines at one quarter scale. Further experiments are being designed to investigate the potential for managing time delays in telerobotics. This paper describes the laboratory, experiments, and some preliminary results."

Jan 1, 2005

By C. T. Morley

The steadily increasing interest in high pressure grinding rolls (HPGR) as a legitimate alternative comminution technology for hard rock applications has led to a proportional increase in the demand for trade-off studies comparing HPGR with more established approaches, typically SAG-based but including AG and stage-crushing designs. The primary trade-off is between a) the higher capital cost typically incurred with HPGR-based designs and b) the higher operating costs of the more traditional technologies. However, if, through circuit design innovation, the capital cost penalty of HPGR circuits could be eliminated or reversed, then the need for trade-off studies would diminish.

Jan 1, 2012

By D. A. Wheeler, Rémi Tremblay

"INTRODUCTIONDuring the last few years, through Column Flotation Company of Canada ltd, the Centre de Recherches minérales has worked on the column flotation of coal, phosphate, feldspar, talc, graphite, copper, lead-zinc and diamond ores. The operating companies and prospective deposits were located in Canada and in other countries. Since these projects were financed by the concerned mining companies, all results remain confidential unless we obtain permission to publish. Three companies have graciously allowed us to use their information which I will describe in this text. These are the Polkowice copper mine in Poland, the North Coast Industries ltd graphite deposit and a talc company which preferred to remain anonymous. I will also describe our 2 inch column which was used for all tests. Data is also given on how to scale-up the 2 inch column to industrial size.Figure 1 presents a schematic of a flotation column. Feed, at a controlled rate and pulp density, enters at about 1/4 of the height of the column from the top. A controlled rate of air is bubbled into the bottom of column through a fine-holed sparger. The column volume between the feed point and the top of the sparger is called the recovery zone. Tailings, at a controlled rate, always slightly greater than the feed rate, discharges from the bottom of the column. This difference in feed and tailings flowrates is called the bias. The floated mineral is carried through the recovery zone on air bubbles which rise into the cleaning zone which is that column volume between the feed point and the overflow at the top. As the bubbles rise in this zone they are washed of gangue material by wash water which enters over the top of the froth layer. The froth layer is maintained at a given depth during flotation but this depth will depend on the froth cleanliness, for quite a bit of cleaning by wash water is accomplished in this layer."

Jan 1, 1988

By Andrew Neale, Len Anderson, Rob Perry

"P.T Freeport Indonesia's new SAG mill commenced operation in February 1995. The reclaim system consists of four apron feeders and a series of three conveyors. The feeders are used in various combinations and relative speeds to blend SAG mill feed. It was recognized during design of the control system that effective automatic control would require dead-time and gain compensation. The successful implementation of the Dahlin algorithm to provide variable dead-time and gain compensation is described and compared to Pl control.RésumeL'opération du nouveau SAG de P.T. Freeport Indonésie a commencé en Février 1995. Le système de réclamation du minerai comprend 4 alimentateurs à tablier et une série de 3 convoyeurs. Les alimentateurs sont utilisés dans une combinaison variée et à des vitesses relatives différentes pour mélanger l'alimentation du SAG. II a été reconnu pendant la conception du système du contrôle que le contrôle automatique demandera une compensation pour le temps de délai et le gain. L'implantation de l'algorithme de Dahlin a été un succès et ii est comparé avec le contrôle Pl.ResumenP.T. Freeport Indonesia inició la operación de un molino semi autogeno (SAG) en febrero de 1995. El mineral es alimentado desde cuatro alimentadores tipo apron feeders y una serie de correas transportadoras. Los alimentadores se utilizan en variadas combinaciones y velocidades para mezclar apropiadamente el mineral que alimenta al molino SAG. Durante el diseño del sistema de control se detectó que el control automático requería de un tiempo muerto y compensaci6n de ganancia. En este documento se describe la implementación del algoritmo de Dahlin, que ha sido exitosa y ha permitido proveer tiempos muertos variables y compensaci6n de ganancia. Ademas se hace una comparaci6n con el Pl de control."

Jan 1, 1996

By Jr. Arcand

Canadian Economy ? Getting Results ???? A stronger Canadian economy ???? National debt cut ???? Taxes reduced, tax-free savings account, support for manufacturing sector ???? Assisting with infrastructure Aboriginal issues affect all Canadians ???? Aboriginal prosperity is in everyone?s interest ???? Conditions for Aboriginal success include: - Indian residential school settlement - resolving outstanding specific claims

May 1, 2008

By R. Bruce Ferguson

"IntroductionThe Beaverlodge Operation of Eldorado Nuclear Limited is a uranium property located near the north shore of Lake Athabasca about 7 miles from Uranium City, Saskatchewan.The mill is a 2000 tpd carbonate leach operation producing a high grade yellowcake concentrate.The Lamella Thickener was purchased to replace a 55 foot conventional unit which had deteriorated beyond repair. The cost of the unit was considerably lower than for a conventional unit, installation was much simpler and the unit is much more compact allowing it to be installed in the mill basement and be insulated completely.The unit was sized according to the results of tests performed both by the supplier and Beaverlodge engineering staff. The supplier guaranteed overflow clarities of less than 100 ppm suspended solids. The Lamella thickener was developed by A. Johnson Co. of Stockholm, Sweden, is manufactured under license by Parkson Corporation of Ft. Lauderdale, Florida and is distributed in Canada by A. Johnson Co. of Montreal."

Jan 1, 1975

During heap leaching of secondary copper sulphide ores operated at low heap temperatures and high levels of leach solution salinity, copper recovery is usually unsatisfactory, due to a slow chemical and bacteriological leaching of the covellite minerals either formed from leaching of chalcocite or naturally occurring in ores. A laboratory test program was conducted to investigate the effect of leach solution temperature in the range of 20 to 50°C on copper extraction during stirred reactor, bottle roll, and short column leaching of fresh or heap leached secondary copper sulphide ores. It was demonstrated that increasing heap temperature is an effective approach for improving recovery of copper from secondary copper sulphide ores. A review of the technologies available for heating heap leach solution or decreasing solution salinity to improve copper recovery from secondary sulphide ore indicates that an integration of copper concentrate pressure leaching with heap leaching is potentially a cost-effective approach. A copper flotation concentrate sample was tested through pressure oxidation with the use of heap leach solutions of varying strengths for the repulping of the concentrate in order to examine its effect on pressure oxidation performance. The test results indicate that use of heap leach solution of high salinity in the pressure oxidation process does not cause a negative impact on the process performance for copper extraction, sulphide oxidation, and recovery of gold (if present) from pressure leach residue, and has additional advantages of removing the bacterially inhibitory aluminum from heap leach solution and generating more acid and ferric iron in the pregnant leach solution. A flowsheet configuration for full integration of the copper concentrate pressure oxidation with heap leaching of secondary copper sulphide ore is proposed and discussed.

Jan 1, 2014

By K. Peake, A. Dalvi, V. Hernandez, S. Chang, M. Oliazadeh

"Ironstone Resources Ltd. is developing the Clear Hills oolitic iron ore deposit in northwest Alberta, Canada. Sources of oolitic iron ore worldwide are abundant and ubiquitous, but there is currently no commercial technology to extract iron from oolitic iron ores. Mineral processing of the ore to generate a commercial iron ore concentrate is very challenging due to the nature of these ores. Accordingly, Hatch and Ironstone are developing a new pyrometallurgical process (Hatch Ironstone Chloride Segregation) to produce metallic iron from high silica and high phosphorus oolitic iron ores. Following the chloride segregation process, the treated ore is subjected to fine grinding. The iron is then separated by magnetic separation. The iron grade and phosphorus content of the final product shows a strong dependence on the separation methodology and the grind size. The pyrometallurgical process has been developed and tested at a lab-scale pilot plant. The commercialization of this technology could provide an opportunity for the development of a new alternate iron making technology. This paper presents the results of test work done on the raw iron ore to create a concentrate and also on the products of the pyrometallurgical process for the production of a high grade 90% metallic iron product.INTRODUCTION Oolite is a sedimentary rock formed from ooids – spherical particles with concentric layers. There are a number of large oolitic iron deposits where the mineralogical form features a low iron content and high concentration of impurities making them presently impossible to exploit on either a technical or economic basis. The fifteen largest oolitic iron ore deposits in the world are estimated to contain approximately 337 billion tonnes of iron ore, which would be a significant source of supply for worldwide steel production. A viable process that can economically recover iron from these oolitic iron ore deposits could become an important new technology to meet future demand in the steel industry. Hatch and Ironstone have demonstrated that oolitic iron ores can be exploited to produce direct reduced iron (DRI). Direct reduction ironmaking is a method for producing solid metallic iron using different techniques compared to the blast furnace process, which is the more conventional ironmaking route. The demand for the construction of direct reduction ironmaking plants has increased in response to the increasing demand for crude steel. It is viewed as a method of providing low-residual iron sources to scrap-based steelmaking in electric arc furnaces."

Jan 1, 2014

By Dave Ecobichon, Éric Côté, Simon Nickson, Michel Leclerc

The feasibility assessment of a mineral deposit requires the construction of a geo mechanical model of rock mass properties, for the purpose of preliminary mine design. The Noranda Technology Centre has been involved in the development of geomechanical models for several mineral deposits at the feasibility stage. Each model is constructed through intact rock testing, geotechnical core logging, geotechnical mapping and rock mass classification. Rock mechanics principles are used to develop conceptual stope designs and propose possible mining sequences. This methodology is applicable to both new mining projects and to the development of new areas within anoperating mine. This paper explains how the geomechanical model is developed and reviews its application to several case studies.

Jan 1, 1996

By Frederick Bird

This paper is based upon a review of studies of mostly Canadian mining companies in Chile, northern Canada, Tanzania, Guatemala, Ghana, Sierra Leone, and the Democratic Republic of Congo. In spite of often well-meaning efforts most mining firms produce wealth in developing areas that largely benefit those immediately involved, sometimes neighboring communities, and often those in the governing strata. Typically mining takes place in enclaves and fosters enclave development, rather than the kind of inclusive wealth development favored by the recently UN published Inclusive Wealth Report. One way by which mining operations can foster more inclusive wealth development is to adopt much broader approaches towards the construction of the various physical and social infrastructures ? roads, water, electricity, health services, schools, security ? required for their own operations by collaborating with diverse regional, provincial, and/or national agencies and businesses to develop these infrastructures for larger populations and areas beyond the immediate sites where they are operating. Established mining firms can also foster more inclusive wealth development by establishing more formal, collaborative relationships with artisanal miners.

Aug 1, 2013

By John A. Allan

Introduction There are times when meditation on the past is worth while. Too often does it happen that in the busy routine there appears t9 be little time for reflection, and little good or benefit to be derived from what has already taken place, or what has become past achievement. Under conditions such as those that prevail at present, consideration is being given to many subjects that a few years ago were not looked upon as worthy of time or thought. The temporary lull in industrial development is permitting of a stock-taking investigation, a perusal of past activities, and a planning for future development with the return to normality. It is not proposed to include much new data in this address, but the endeavour will be made to survey, in resume, the sequence of events which led up to the birth of the mining industry in Canada, and to show how, as new discoveries were made, the centres of interest changed from time to time until mineral development extended across Canada from the Atlantic to the Pacific. It will appear, also, that external causes have accentuated mineral development at one time and retarded it at another. Early Records A, historical background to the mining industry extends even to an earlier date than the discovery by white men of that part of the continent of North America represented by Canada. It has been stated that the aborigines were still in the neolithic stage when the white man arrived. One metal only was known to the natives, and that was copper, obtained from possibly many parts of Canada, but particularly from the shores of lake Superior in Ontario, from the Coppermine river on the Arctic coast, and from die coastal regions of British Columbia.

Jan 1, 1933

By A. Idegami, M. Imamura, S. Heguri, Y. Ozaki

"Nickel powder can be produced by the reduction of a nickel ammine complex solution by hydrogen at high temperature and pressure. To minimize the deposition of fine nickel on the surface of the reactor and other equipment, seed crystals are added to the initial solution to promote nucleation of the nickel powder. Such seed crystals catalyze the precipitation of the nickel particles on the surface of the seed and enhance grain growth. In this study, nickel nuclei were precipitated by the addition of a polymer to the nickel ammine complex solution, resulting in the production of nickel powder. Thus, we herein propose a model that explains the effect of the polymer in the precipitation of nickel nuclei.INTRODUCTIONNickel powder is commonly produced via a hydrometallurgical process from the hydrogen reduction of a solution containing a nickel ammine complex at high temperatures and pressures, and this process was commercialized in the 1950s by Sherritt Gordon (Sherritt International, Canada, Benson & Colvin,1973; The Staff, Research and Development Division, Sherritt Gordon Mines, Ltd., 1958).In the above transformation, upon the injection of hydrogen gas into the solution, nickel is reduced as outlined in Equation(1), ultimately resulting in the production of nickel powder.Ni(NH3)nSO4+ H2?Ni+ (NH4)2SO4+ (n-2)NH3(n:2–6)(1)In this process, seed crystals are added to the reactor to suppress the precipitation of fine nickel (scaling) and to enhance nickel reduction (Benson & Colvin, 1973; Mackiw, Lin & Kunda, 1957). More specifically, iron sulfate and a small amount of dispersant polymer are added, which leads to the formation of nuclei. Upon subsequent hydrogen reduction, the reduced nickel can then be deposited on the nuclei, allowing nickel particle growth to take place. However, this results in iron contamination in the final nickel product, and so the use of pure nickel as a seed crystal is desirable to produce high quality nickel powders."

Jan 1, 2017