Search Documents

By Alex MacEachern

Air is the gaseous substance that envelopes the earth and forms its atmosphere. It is remarkable in the constancy of its composition; for while this is being continually changed as the result of the respiration of men and animals, and by addition of gases arising from organic changes and the products of combustion, it is ever being brought back to normal and the proper balance restored by the processes of plant and vegetable life. Nature sees to it that the air in which we live and breathe is kept purified. This does not apply to the air in a coal mine, where there are no natural forces to change and make use of the different gases formed or evolved, and where mechanical ventilation is the only effective means of keeping the air pure. The atmosphere consists of oxygen and nitrogen, not in the combined state but merely mixed. By volume, the composition is: oxygen, 21 percent, nitrogen, 79 percent, there being included with the latter small quantities of such substances as water vapour, carbon dioxide, nitric acid, ammonia, ozone, argon, neon, and organic gases. Of the two principal gases which form air, oxygen alone supports life. When air is inhaled into the lungs the oxygen is absorbed by the blood, which carries it through the body to nourish and energize it. Exhaled air consists of water vapour and about 4 per cent carbon dioxide, with from 16 1/2 to 17 per cent oxygen and 79 per cent nitrogen; the oxygen alone having been drawn on to any considerable extent.

Jan 1, 1930

By E. Dernedde

Cell rooms of aluminium smelters have large openings in the sidewalls and in the roof. These openings provide a high ventilation rate, which removes heat and contaminants emitted by the reduction cells and thereby ensures acceptable working conditions inside the cell room. However the large openings make the airflows through the smelter building sensitive to the wind. In this study equations for the airflow through the openings of a smelter building exposed to crosswinds were developed and verified against plant measurements. The equations were then used to estimate the airflows through a two-storeyed smelter building containing VS Soderberg cells. Wind protection by wind-covers over the sidewall openings and by upwind buildings made the airflows through the building less sensitive to the wind. Physical and mathematical modelling showed that working conditions inside the wind-protected cell room would be acceptable for crosswinds at speeds up to 16 km/h. These predictions were confirmed by measurements taken in a VS Soderberg smelter.

Jan 1, 2007

By V. G. Papangelakis, J. E. Dutrizac, G. Azimi

A new model capable of predicting the solubility of calcium sulphate solid phases in zinc sulphate processing solutions from 25 to 95°C was developed. The model uses the Mixed Solvent Electrolyte (MSE) model of the OLI systems software to calculate the mean activity coefficients of the electrolyte species. The model was tested using recently developed experimental measurements. It was shown to predict accurately the solubility behaviour of calcium sulphate in multi-component zinc processing solutions containing ZnSO4, H2SO4, MgSO4, MnSO4, Fe2(SO4)3, Na2SO4 and (NH4)2SO4. The model can also explain the complex effect of coexisting metal sulphates on the solubility of the CaSO4 phases. The model is a practical tool for assessing the process chemistry of a wide variety of complex aqueous processing streams.

Jan 1, 2008

By S. P. Chong, N. C. Shih, G. A. Turner

Fine powders, with the bulk of the particle diameters Jess than 10 microns, were aerated so that each particle was, on the average, separated from its neighbours by 1.3 to 2 mean diameters. In this state, measurements were made of the viscosity and settling rate of the powder, and the interfacial tension between it and a moist pellet. From the viscosity measurements, qualitative analogies are drawn between the behaviour of the aerated powder and that of a dense gas near its critical point.

Jan 1, 1970

By T. Grammatikopoulos, SGS Canada Inc.

"The Nechalacho rare metal deposit, located in the Northwest Territories, Canada, is currently being taken through Feasibility Study by Avalon Rare Metals Inc. QEMSCAN analysis and supplementary electron microprobe analysis were utilized to identify and quantify the mineralogy of the deposit, and determine REE distribution among the minerals. QEMSCAN mineralogy was performed to provide textural information on the mineralization, determine the variability of the ore and identify REE domains, and the liberation and association of the REE minerals. The sample matrix consists predominantly of silicate minerals. The REE minerals include allanite, monazite, synchysite, columbite, fergusonite, and bastnaesite. Zircon is present in considerable amounts and is a REE carrier. Fergusonite and zircon account for most of the HREE, and monazite, allanite, synchysite and bastnaesite the LREE. QEMSCAN mineralogical data is extremely valuable in assessing the mineralogy of the ore. The data are implemented to define the mineralogy of the ore body, support metallurgical test work, and predict recoveries and grades.INTRODUCTIONThe term rare earth elements (REE) is used to describe the 15 lanthanide elements or metals and, more recently, the metals yttrium and scandium, which display similar physical and chemical properties.Economic and potentially economic REE deposits form two main groups, a more commonly occurring “light rare earth element” (LREE) group containing lanthanum, cerium, praseodymium, neodymium, and samarium and a less commonly occurring “heavy rare earth element” (HREE) group which, in addition to the LREE, contains elevated concentrations of the more valuable REE, europium, gadolinium, terbium, dysprosium, holmium, yttrium, erbium, thulium, ytterbium, lutetium and scandium. The first group is hosted primarily by carbonatites and the second by highly alkaline (Na + K > Al) silicate igneous rocks. The LREE are produced mainly from bastnaesite, monazite, etc., while HREE are produced almost exclusively from low-grade secondary ion adsorption clay deposits in which the REE are adsorbed onto the surfaces of kaolinite and halloysite, clay minerals produced by the weathering of granite and sediments. HREE are also found in fegusonite, zircon, xenotime, etc but are not produced presently from these minerals. China is responsible for 97% of the World’s production of the REE, mainly from the giant Bayan Obo, carbonatite-related deposit and from the clay deposits mentioned above.Quantitative automated mineralogy is increasingly being applied to ore deposits. It helps users to understand and improve mineralogical parameters for geological and metallurgical purposes. Data include textural characterization, to quantification and distribution of ore and gangue minerals, liberation and association of the REE minerals. The data can be used to define mineralogical domains and predict the metallurgical response of the ore (Gunning, de Souza, & Grammatikopoulos, 2009)."

Jan 1, 2012

By Karl J. C. Harries

"7.1. INTRODUCTIONThis chapter addresses the joint venture and examines a number of general concepts of the joint venture relationship. Chapter 8 looks at some specific concepts related to the provisions of a joint venture agreement, which are equally applicable to a shareholders’ agreement or other contractual relationship. The term “joint venture” is used because the author is a common law solicitor (a matter of convenience for which apologies are offered to civil law readers), but it should be noted that, in many aspects, the legal structure of an entity is irrelevant. It is the relationship of the parties, be they venturers or shareholders, that is important, and the areas of concern are surprisingly similar (except for terminology).The details of the joint venture relationship and agreement could fill several books. Accordingly, this chapter and the next focus on selected topics that appear to have caused problems or confusion or to be the basis for disputes. And remember that, although the following discussion is in the context of a joint venture, many of the comments apply, either directly or indirectly, to virtually any common undertaking and the agreement defining it.For interest’s sake, this chapter starts with a summary of some of the earlier types of agreements and arrangements that have evolved into the joint venture agreement of today in Canada, the philosophy of their format, and the reasons for their demise.7.2. EVOLUTION OF THE CANADIAN JOINT VENTUREThe Early DaysMuch of the opening up of Canada’s north is due to exploration for and development of mines. The early discoverers were relatively free to roam and explore at will and, if they were fortunate enough to find something, they dealt with the appropriate government to acquire exploitation rights. The early interests lay in gold or silver. Workings were small, usually worked by the owner alone or with only a couple of helpers to extract the native gold or silver. If the owner wanted to move on, he could sell his property outright and use his stake to look elsewhere.As logging and mining camps were opened, the development of better roads and railways made access easier. Entrepreneurs saw the opportunity to make money by assembling large parcels of land and working them as a single operation. In order to do this, some owners who were not ready to sell out had to be convinced to do so through more attractive offers"

Jan 1, 2003

By Margaret Anne Stephenson

Today, in Australia, it is increasingly common to see agreements between Indigenous peoples and resource companies being achieved generally as Indigenous Land Use Agreements or agreements pursuant to the ?right to negotiation? process under the Native Title Act 1993 (Cth). Despite progress in this area, resource development on Indigenous lands is not without its challenges for both the resource proponents and the Indigenous parties. History demonstrates that resource development on Indigenous lands has produced struggles between the traditional owners of the land and the resource proponents. In Australia their relationship is generally defined by issues of access to land and assuring continued access to the land for the life of the project. In this context, divisions in Indigenous communities often emerge. The proposed resource project can have the effect of polarising members of an Indigenous community. It may be regarded by some traditional land owners as an advantageous opportunity for the community and by others as a hazard to country and culture. The process of agreement making has proved not only a test for the Indigenous community but also for the resource proponent. In this paper we undertake a contemporary case study of a proposed Australian resource related-development project on Indigenous lands. This project involved a multi-billion gas hub precinct proposed at James Price Point in the Kimberley region in Western Australia. The James Price Point proposal produced a litany of challenges for all parties. The traditional owners faced fundamental social and human rights issues, including a minority opposition to the project, the project's potential cultural heritage impact, the threat of compulsory acquisition of their native title interest by a State government due to an initial failure to settle an agreement, a fracture of their unsettled land claim and a minority rejection of the agreement ultimately reached. Additionally, the ?green? lobby also rejected the proposed gas hub on environmental grounds bringing the green lobby into direct conflict with both the traditional owners in favour of the project and the resource proponent. Ultimately, Woodside announced its decision not to proceed with the proposed gas precinct at James Price Point, in April 2013. In this paper we analyse the complexity of the James Price Point gas hub negotiations with the traditional owners which resulted in an Agreement that promised to deliver substantial benefits for the Indigenous communities. We question why such a favourable and beneficial agreement for the Indigenous community also produced the plethora of challenges and concerns and we consider how future negotiation processes could be better structured to avoid the difficulties that have confronted Indigenous land owners and resource proponents alike.

Aug 1, 2013

By J. Duby

"A description is given of a series of tests performed to determine the comparative effects which dynamic and static straining, in compression, have on the physical strength properties of mild steel and an aluminum alloy. The dynamic deformation was imposed during the passage of single stress pulses of about 100 micro-second duration. These pulses were recorded with strain gauges mounted near both ends of the specimen. The resulting records were analysed using a simple wave theory; there from the dynamic stress-strain curves for the respective metals were deter-mined and were then compared with the static stress-strain relation. The respective hardnesses of the metals after deformation are evaluates by means of static stress-strain curves in compression. The micro-structures of the metals before and after deformation are also shown. It is observed that dynamic de-formation considerably modifies the rate of strain hardening. This modified hardening appears to be persistent. The observed differences in physical strength properties and micro-structures are discussed in the light of the accepted dislocation theory for metals."

Jan 1, 1960

By John L. Mero

"The ocean has served humanity as a source of raw materials for thousands of years, but only on a minimal scale relative to its potential. Exploration programs have shown the ocean to contain a large number of mineral deposits of great extent and attractive grade. Recent research has indicated that a number of these deposits can be economically exploited with present-day technology and that the cost of winning many industrially important minerals from the oceanic deposits is potentially much less than that of winning similar minerals from land deposits. Although the finding of mineral deposits in the sea is a relatively simple matter at the present time, the exploitation of many of these deposits has lagged due to the lack of the availability of specific mining techniques for the individual deposits. Within the past two years, however, several developments have taken place in the design and testing of ocean mining systems in depths of water as great as 12,000 feet which indicate that the problem of mining in the ocean may soon be solved.Within the next decade, the ocean should prove to be a major source of many minerals for society and should come to dominate as a source of such metals as copper, nickel, cobalt, manganese, etc. Within a few years of the initiation of the mining of the deep-sea metalliferous nodules, land sources of such metals as nickel, cobalt, copper, manganese, etc. will be seriously affected and it is conceivable that the present structure of the world mining industry will undergo a substantial change in character."

Jan 1, 1972

By Mike Johnson, Greg Andrews, Niels Verbaan, David Dreisinger

"The Search Minerals Foxtrot project in Labrador represents a significant Canadian resource of rare earth elements rich in the sought after heavy rare earth elements (19.8% HREE/TREE). A preliminary economic assessment of the project indicated that the project is technically feasible and economically attractive. A variety of metallurgical test programs have been undertaken which have led to significant streamlining and simplification of the process flowsheet. The improved flowsheet should allow Search to reach production earlier and will use conventional processing equipment. The results of these test programs are presented and discussed in this paper INTRODUCTIONSearch Minerals Inc. (Search) is exploring and developing a number of deposits for rare earth element (REE) recovery in Labrador, Canada. The Port Hope Simpson District is in the southeast of Labrador and is highly prospective for heavy and light rare earth elements. The Foxtrot deposit sits within the Port Hope Simpson REE District (Figure 1), which is 70 km long by up to 10 km wide. The infrastructure available at Foxtrot is excellent; a deep-water port, air strip, and road and power infrastructure are pre-existing at St. Lewis. The three communities of Port Hope Simpson, St. Lewis and Mary’s Harbour are in close proximity to the site."

Jan 1, 2016

By C. A. Lavery

A DISCUSSION is presented of natural gas production and field processing equipment as now utilized in the gas producing areas of the United States, with reference to use of such equipment in Canadian gas areas. The scope of the paper is confined to a general description of various types and methods of using surface production equipment. The discussion is divided under two general groups: well-head production equipment, and field processing. The first will be concerned primarily with indirect heaters, separators, knockouts, and special versions of this equipment. The second major group includes the field processing equipment for handling natural gas. A delineation should be made here as to the meaning of field processing as used in this discussion. We will limit our term to mean such processing equipment as may be used in producing fields to process gas or its by products in a manner that does not require conventional plant practices either in operation or supervision. This covers such equipment as is necessary to complete preparation of gas for sale to pipeline and/ or is necessary to recover valuable components. Under this heading we will discuss glycol dehydration, solid desiccant dehydration, low-temperature separation, mechanical refrigeration, and desorbtion-stabilization. These are all processes involved in preparing gas for final sale or disposal. They do not include the more conventional and large-scale plant process systems.

Jan 1, 1956

By Minerals Refining Company, Gerald Luttrell, Biao Li, Robert Bratton, Roe-Hoan Yoon, Stan Suboleski, Nikhil Gupta

Flotation is regarded as the best available method of upgrading coal and mineral fines in the mining industry. However, its efficiency deteriorates rapidly with decreasing particle size. Furthermore, ultrafine concentrates are difficult to be dewatered economically. Due to these technological problems, some operators are forced to discard at least part of the ultrafine materials to tailings (or refuse) ponds, causing significant losses of valuable resources and creating environmental concerns. To address these technological issues, a new separation process named hydrophobic-hydrophilic separation has been developed on the basis of the recent advances in the science of hydrophobic interactions. The results obtained to date show that the process can recover and dewater ultrafine particles simultaneously with high separation efficiencies. Following a series of extensive laboratory tests, the process has been scaled up to proof-of-concept and pilot-scale continuous tests. The results obtained with desliming cyclone overflows, screenbowl effluents, and by-zero coal flotation feeds can be cleaned to less than 4% ash and moisture with over 97% organic matter (or coal) recoveries. The results obtained with mineral fines also showed encouraging results.

Jan 1, 2016

By J. B. Mawdsley

A LITILE north of the geographic centre of the Province of Saskatchewan, 150 miles north of the city of Prince Albert, is a narrow green-stone and sedimentary belt of pronounced structural characteristics. This belt, generally known as the Sulphide Lake belt, is about two and a half miles wide. During the past three years prospecting has uncovered numerous gold-bearing showings occurring chiefly along the centre of the belt for a distance of at least nine miles. The number of these showings, the nature of some of them, and their relationship to strong structural features, make it altogether likely that intensive work will eventually locate ore-bodies that will be of economic importance. The discovery of gold in the fall of 1938 on the south shore of Mackay lake, about five miles northwest of the Sulphide Lake gold-bearing belt, indicates that there are neighbouring zones of interest. This paper, an attempt to outline the present status of the interesting mineralized belt, is based largely on the information gained on a five-day tour of this district, made in August, 1939, on behalf of the Department of Natural Resources of the Province of Saskatchewan. The Sulphide Lake belt is named after a small lake centrally located in it. This lake and others are just north and within short portage distances of some of the long bays along the north shore of Lac La-Ronge, an irregular, island-studded lake, about twenty miles in diameter, in relatively rocky Precambrian country, just north of the Palaeozoic contact. The fur-trading post and settlement of Lac La-Ronge is on the west shore of this lake and a road, now under construction, will shortly link this community with the city of Prince Albert. In the past, the most direct route was an indifferent canoe route, in part following Montreal lake and river; more recently, the aeroplane has made this section easily accessible.

Jan 1, 1940

By A. M. L. Cushing, S. Kelebek

Presently, adsorption is one of the effective methods of removing toxic contaminants from waste waters. The contaminants from metal mining industrial operations include an effluent water containing various types of heavy metal species at concentrations beyond the maximum allowable limits, which are 0.5 ppm and 0.3 ppm for nickel and copper species, respectively. Adsorption behavior of copper ions pre-chelated with diethylenetriamine (DETA) and triethylenetetramine (TETA) onto natural bentonite and peat has been investigated. Both natural bentonite and peat was found to be capable of removing these copper-polyamine complexes from aqueous solutions relevant to process water effluents. However, the adsorption capacity of bentonite was significantly higher than that of peat. Two models were used to study the adsorption kinetics: a pseudo-first-order rate expression and a pseudo-second-order rate expression. For both adsorbents, the data conformed best to the pseudo-second-order rate expression. Representation of the experimental data through adsorption models was also investigated. Out of the four cases considered, namely, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms, it was found that for both bentonite and peat, the copper polyamine adsorption data conformed best to the Dubinin-Radushkevich adsorption model. The Langmuir model also represents the bentonite-copper polyamine adsorption system reasonably well as the second best case, suggesting that the amount adsorbed on bentonite might be a monolayer with strong affinity.

Jan 1, 2015

By S Grönstrand, C. Perez, A. B. Yañez, F. Coddou, P. Morales, H. Elgueta

"The TankCell® 300 forced air flotation cell designed and built by Outotec, with active volume of over 300 m3, was installed at Codelco’s Chuquicamata concentrator in September 2008. After that, a program was conducted, where the new cell was tested against the plant’s existing flotation cells of type TankCell® 160, with an active volume of over 160 cubic meters.Testing program was exhaustive and detailed. Grade-recovery curves for each setup were reported, along with recoveries by particle size. Secondly, operational characteristics like air feed and froth height setpoints, and power consumption are compared side-by-side. As the third topic, gas dispersion characterization included velocity mapping, holdup, bubble size and bubble surface area flux operating range. The fourth area of interest was the retention time distribution (RTD) of the 300 and 160 m3 cells in comparison. A detailed campaign using radioactive tracer tests was conducted to clarify this.All of the investigations mentioned above are reported in separate papers for more detail. The aim of this paper is to collect the key findings, and present them in real terms, always referring to operability and metallurgy of the cells. It is destined for people designing new plants and to those improving and expanding existing ones. The most frequently heard question is: will the new large cells operate at same efficiency as the smaller ones. In short, the answer is: NO. They operate at improved efficiency!INTRODUCTIONIn the last two decades of minerals processing, there have been three dominant trends of development in the flotation technology: equipment scale-up, cell characterization and circuit modeling. Equipment scale-up has been rapid in the past two decades. In the year 1990, the largest flotation cell in use was 50 cubic meters of size. This year, 300 cubic meters is the largest installed cell. Characterization of flotation equipment and circuits is a very popular subject nowadays and has helped many operations to improve their recoveries through better control strategies, for example by using optimized air feed and level control profiles (Gorain, 2005), (Doucet, Gomez, Finch, 2006), or through better maintenance (Coleman, Urtubia, Alexander, 2006). Characterization work is closely linked to circuit modeling. The aim is to produce sufficient amount of data to allow reliable model building. These models are then used to design new circuits and to improve existing ones. So in summary, these three lines of development have slightly different aims – from capital and operational cost to performance optimization. Ultimately, they converge in the same end result – maximizing the profitability of the operation. Following chapters will summarize the extensive test work and scientific studies at Codelco Chuquicamata. The aim was to compare a TankCell® 300 cell, with nominal volume of 300 m3, against two TankCell® 160 machines, with 160 m3 volume in each. The work should yield answers to questions: does the larger cell produce similar results – is the scale-up successful?"

Jan 1, 2010

By F. W. Gray

Ideal utilization of the heat energy in coal should theoretically be secured by supplying each atom of combustible material present with the exact quantity of oxygen necessary for complete combination. An intimate and equal admixture of the fuel particles with air is therefore to be sought. Coal, or the combustible substances of which coal is composed, may be used in solid or liquid or gaseous form. The use of coal in small particles intimately mixed with air is, in effect, a specification of coal in pulverized or dust form. There has been much important development of this manner of using coal, which may be instanced as the outstanding advance in the use of coal as a solid. The completeness and efficiency of combustion in a properly designed dust-fired furnace permits the use of locally available coals of inferior quality, and enables them to be used commercially instead of imported coals of better quality. That is to say, some grades of coal of low calorific value, that are not economically useable in lump form on grates, are useable in pulverised form, because of the more complete combustion thereby obtained, and the consequent more efficient results. In the case of coals that are unsuitable for steam-raising in grate-fired furnaces, because of clinker troubles, (arising usually from a combination of high sulphur content and low-temperature fusibility of the ash content) use in pulverised form has obvious advantages, and in addition gives the benefit of any heat units that are contributed by free sulphur in the coal.

Jan 1, 1924

By A. G. Roach

Introduction This paper deals with the operations and plant of the Craigmont Corundum Project, formerly of Wartime Metals Corporation but now under the Mines Section of the Resources Development Branch of the Department of Reconstruction and Supply. Corundum is recovered by the re-treatment of an old tailing deposit at Craigmont, Ontario. Crude concentrates so produced are shipped to the plant of the American Abrasives Company, Inc., at Westfield, Mass., for final processing and distribution to the abrasive industry. The plant was recently described in a paper entitled Craigmont Corundum which was presented by the writer before the Chicago meeting of the A.I .M.E. in February, 1946. General The Project is located on? lots 4 and 5, concession XVIII, township of Raglan, Renfrew county, Ontario, near the village of Combermere, which is on Highway 62. The property is about 135 miles from Ottawa. The general area enjoys a pleasant climate with moderate summer temperatures, though the winters are rather severe, the mercury frequently falling to - 35 deg. F. The excellent boating, fishing, and hunting have made the district a favourite resort for tourists. Lumbering is the main industry. Some farming is carried on, but the soil is poor and much of the land is hilly and rocky. There are no other operating mines in the immediate vicinity, though several 'industrial minerals', including mica, feldspar, nepheline, beryl, socialite, and others have been produced in the area. The district is drained by the York and Madawaska rivers and is generously dotted with large and small lakes. The general elevation is about 1,000 feet above sea level, though numerous hills rising several hundred feet give a rolling appearance to the landscape.

Jan 1, 1946

We describe a new method of characterising the effect of dissolved materials on the rate of coalescence of bubbles in aqueous media. Single bubbles were allowed to rise to meet the surface of an aqueous solution, and the time of persistence between arrival and bursting of bubble was measured as a function of solute concentration. A laser beam was placed just above the surface of the liquid, with a detector in the light path, so that any disturbance at the surface could be seen as a break in the beam. The arrival of a bubble at the surface could be detected from the behaviour of the trace on an oscilloscope, and when the bubble broke, another significant change in the signal could easily be seen. The time between disruptions was reported as the persistence time. The effect of a homologous series of n-alcohols (C1 to C8) on the persistence time was measured, in aqueous solution. It was found that with increasing concentration of a particular solute, the persistence time increased up to a point, and then declined. However the magnitude of the persistence time was found to increase with increasing numbers of carbon atoms in the molecule. Bubbles of 1, 2 and 3 mm diameter were used. Persistence time increased with increasing bubble diameter, the maximum values observed being of order 100 secs. For a given solute, the persistence (drainage) time increased with increasing bubble diameter. The concentration Cmax at which the maximum persistence time was observed, was found to be independent of the bubble size. It decreased uniformly as the carbon number increased, and was well correlated by the function y1/2 (dy /dc) -2 I dc)-2 . There was no apparent correlation with the surface excess at maximum persistence time.

Jan 1, 2006

By Sylvie Lévesque, Cory Hennessey, Daniel Amariei

"In the iron ore industry, fine particles recovery is an important concern in terms of process performance and production costs. Continuous efforts are thus devoted to increase the efficiency in handling these fines.The Reflux Classifier (RC) is a relatively new technology that is mainly used in the coal and industrial minerals industries. The operating principle of this system is based on three mechanisms: hindered settling, autogenous dense medium and lamella settling. A preliminary evaluation of the Reflux Classifier technology for the beneficiation of iron ore fines was formerly done at the pilot scale using a RCTM300 unit. The good results obtained, using iron ore fines from screened spiral stream, made this technology very attractive for the iron industry. However, the high capacity of the RCTM300 unit (1–3 t/h), makes it unsuitable for R&D purposes. Thus, a smaller unit, the RCTM100, was assessed to validate the performances obtained with the RCTM300.This paper summarizes the performances obtained with the RCTM100. The challenges of the scale-down related to the adaptability of this technology to the iron ore industry are also presented. The results are compared to the RCTM300 performances, as well as benchmarked against sink-float tests. The metallurgical results on feed and products issued after the test work with the RCTM100 unit are supported by mineralogical characterization using a Mineral Liberation Analyzer.INTRODUCTIONFine particles recovery by physical separation means is a historical concern (Holland-Batt, 1992; Peukert and Wadenpohl, 2001; Srivastavaa et al., 2001; Majumder et al., 2003). Attempts to improve fine particle recovery at the laboratory, pilot and industrial scales adopting different strategies with traditional equipment or assessing new promising devices such as the MGS (multi-gravity separator), the Kelsey jig, the Yang jig, etc. (Kim, 2002; Goudreau, 2008; Kerr, 2012) have yielded variable success."

Jan 1, 2016

By Joseph Bradley

THROUGHOUT this article, minerals used in the paint industry are designated 'pigments'. They may be classified in two groups: (1) Pigments which are used in the state in which they occur in nature, requiring only mechanical preparation. (2) Pigments which require heating or chemical treatment before use, in order to obtain from them a product of the desired quality or shade of colour. They may be further classified according to colour, as follows: White Pigments .-These include calcium carbonate (chalk, marble), gypsum and alabaster, kaolin-or china-clay, and magnesia. However, the white pigments most extensively used are compounds prepared chemically from minerals containing lead, zinc, titanium, and antimony. The white pigments are of particular importance because, not only are they used by themselves, but they also serve as adjuncts to other colours for the production of special shades. Yellow Pigments.-These are mainly naturally occurring ferric hydroxides, as limonite and bog iron ore, or similar. compounds prepared artificially. Brown Pigments .-Pigments of this group are distinguished for their beauty and depth of colour, and many of them are used in the finest of paintings. Familiar names are sienna, umber, and Vandyke brown. They are for the most part ferric hydroxides, containing varying amounts of water; but the group also includes a manganese brown, which consists chiefly of a mixture of oxide and hydroxide of manganese. Red Pigments.-Chief among this group is ferric oxide, known under various trade-names, such as Canadian red, Persian red, etc., and also the much prized and somewhat rare vermilion. The pigment used is either naturally occurring hematite, de-hydrated limonite, or artificially produced red ferric oxide.

Jan 1, 1937