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By Brian Lewis

"IntroductionThe leaching method selected for the dissolving of uranium ore depends in part on the physical characteristics of the ore, as well as the uranium mineralization. There are two main methods of leaching employed in uranium circuits in North America, one being ""Carbonate Leaching"" on sandstone, and pitchblende type ores, and ""Acid Leaching"", on quartzite type ores.This chapter deals with the acid leaching of uranium ores found in the Elliot Lake area, using sulphuric acid, for the leaching reagent, and ""pachucas"" for the contactor.The basic leaching process involves the pregrinding of the ore and the mixing of the ore with hot sulphuric acid, the mixture is air agitated, the air being used to oxidize the ore as well as produce agitation. The chemical reaction is as follows: Uranium Oxide + Sulphuric Acid = Uranyl SulphateThe following equations show the actual dissolution of the ""Hexavalent Uranium"", which show that more than one ion or complex of uranium is possible.Uranium DissolutionsI. UO, + 2H-(UOJ + H,O2. (UO,) + SO, = -UO, SO, (Uranyl Sulphate)3. UO, + SO,-(UO, (SO,),)=4. (UO, (SO,),)= -(UO, (SO,),)'Test work carried out in the laboratory as well as in the plants has determined the most efficient methods of extracting the uranium from the ore. A very important factor that has to be determined during initial test work are the amount of acid consumers in the ore. Within the Elliot Lake orebodies are minerals such as chlorite schist, diabase, and basement material, all very high acid consumers, consuming up to 1000 lbs. of acid per ton of ore. Of these minerals only the chlorite schist contain any uranium at all.The following are the operating parameters that have to be controlled in the plant:I. sulphuric acid concentration2. temperature of the mixture3. agitation4. liquid solid ratio5. reaction time6. particle size of ground ore"

Jan 1, 1989

By A. L. Rutledge, R. S. Nichols

"Waste dump development at the Fording River Operation s in British Columbia began in 1971. In 1981, several unique as well as unplanned situations provided an opportunity to study water flows through waste dumps.The key to the drainage is naturally segregated rock sizes .created by end dumping from the crest of a pile. The largest size material accumulates at the toe. Flow rates along the base of the studied dumps varied from 2,800 to 13,500 m3/day or 0.032 to 0. 156 m3/s (1.2-5.5 cfs}. Sediment concentrations in the water ranged from 1 to 1,800 mg/I.This paper describes water flows through dumps of varied lithology and maturity. The results suggest that neither long-term water flow nor contained sediments in small streams are jeopardized when crossed by end-dumped fills.IntroductionThe Fording River Operations are located in southeastern British Columbia approximately 115 km north of the United State s and 10 km west of Alberta, within the medial range of the Rocky Mountains. All production is carried out at elevations ranging between 1,600 and 2,200 m above sea level.The property is within a continental climatic zone, with temperature extremes of - 40°C in January to +35°C in July. The average annual precipitation of 335 mm of rainfall and 390 cm of snowfall feeds the numerous seasonal, small drainage courses along the Fording River valley.Since start-up in 1971, 149 million bank cubic met res of waste from truck-shovel and dragline mining have been placed in numerous dumps or ""spoils"". The dumps were developed to the point that several unique situations could be studied. During the peak run-off period of May-June 1981, water flow studies were performed on dumps of varied lithology and maturity. This paper describes the results of the study."

Jan 1, 1982

By James Tuer, John R. Goode, Jim Cambon

"Hudson Resources Inc. (Hudson) has defined a major resource of high purity anorthosite (calcium feldspar) assaying about 30% Al2O3 at the White Mountain (Naajat) deposit in Western Greenland. Extensive beneficiation and evaluation testwork has shown that the material can be simply beneficiated to produce a feed material ideal for the production of low-alkali E-glass used for making glass fibre. An offtake agreement is in place with a major US fibreglass manufacturer and, subject to the mine construction schedule, shipments are scheduled for late 2016 or early 2017. In parallel with the E-glass program, Hudson has completed an initial program of metallurgical testwork which shows that the White Mountain anorthosite can be processed by hydro- and pyro-metallurgical processes to yield either smelter-grade alumina (SGA), suitable for conversion to aluminium metal, or a high purity, chemical/specialty-grade alpha-alumina (CGA) commanding a premium price. The process includes dissolution of the anorthosite in hydrochloric acid, HCl sparging to precipitate aluminium chloride hexahydrate (ACH), recycle of the ACH filtrate to leaching with a bleed stream processed for HCl regeneration from CaCl2, and two-stage calcination of the ACH to regenerate HCl and produce SGA and/or CGA. Calcium silicate and amorphous silica are marketable by-products. This paper discusses the White Mountain anorthosite deposit; the process testwork completed to develop production processes for SGA and CGA; production plans, and indicative economics.INTRODUCTIONHudson Resources Inc. (Hudson) holds a 100% interest in the Naajat Exploitation Licence in Western Greenland that cover the White Mountain high-calcic anorthosite deposit. Anorthosite is a calcium aluminosilicate of slightly variable composition but generally containing about 30% Al2O3. The alumina content is similar to that in bauxite and anorthosite has long been studied as a feedstock for the production of alumina. Other potential uses include feedstock for the high-end fiberglass (E-glass) industry and as a filler for use in paint and plastics."

Jan 1, 2016

By Jacob Wood, Robert Matusewicz

The Outotec® Ausmelt Top Submerged Lance (TSL) Process has achieved widespread commercial acceptance over the past 40 years for the processing of copper, nickel, lead, tin, zinc and precious metal bearing feeds. The continual development and evolution of the technology during this period has resulted in a more intense smelting process with higher energy efficiency and lower operating costs. More recently, considerable effort has been invested in decarbonisation of the process through improvements such as increased oxygen usage, dry feed injection and use of low-carbon auxiliary fuels. This paper covers a number of these recent advances to the technology and highlights their impacts on energy consumption and CO2 emissions for a range of non-ferrous smelting flowsheets. INTRODUCTION Relentless demand for improvements in the profitability, safety and environmental performance of non-ferrous smelting plants has driven a continual development and evolution of processing technologies in this industry. In response to these demands, a number of bath smelting technologies have emerged over the past 40 years and have been implemented for the treatment of primary and secondary feedstocks. The Outotec® Ausmelt Top Submerged Lance (TSL) Process (henceforth Ausmelt Process) is one such bath smelting technology which has been widely adopted in a large number of greenfield projects and brownfield plant modernisations (Wood & Hughes, 2016). Emissions of CO2 from the production of non-ferrous metals represent approximately 4-5% of global totals (Rankin, 2012), comparable with the almost 10% attributed to iron and steel production. Despite significant improvements in the energy efficiency of modern smelting technologies (Coursol, Mackey, Kapusta & Cardona Valencia, 2015), primarily through increased oxygen usage, further innovation and development is still required to address their reliance on fossil fuels such as coke and coal. Transformation of the non-ferrous smelting industry to low-carbon technologies and process flowsheets is lagging behind the power and transport sectors, which have witnessed significant growth in clean/renewable energy technologies to reduce CO2 emissions and address the issue of anthropogenic climate change (IRENA, 2018; IEA, 2018).

Jan 1, 2019

By Max W. Ball

YOU have been kind enough to ask me to speak to you on "The War and Anglo-American Relations." A speaker always takes the liberty of putting his own interpretation on the scope of his subject. I am going to exercise that privilege, and try to look back over a generation of Anglo-American relationships and forward beyond the present war. I should like particularly to consider responsibilities as well as relationships. A more accurate caption for what I am going to say would be "Anglo-American Responsibilities.?? THE WAR WILL BE WON I am assuming that sooner or later we shall win this war. History and economics point to the same conclusion, that Germany has attempted the impossible and that the seeds of defeat are already sown. As to one ecof1:omic factor, I am already on public record as believing that Germany's oil supply is inadequate for the war she has launched. That opinion is unchanged. Aside from such tangible factors, moreover, I am convinced that the spirit of freedom is unquenchable, and that no combination of powers will be able to rout it from the British Commonwealth of Nations and the United States. Stronger even than this conviction is my faith in a God who will not suffer the defeat of man's aspiration to be master of his own soul. I am sure that all of you share that faith, and that we need not argue it. We can start with the assumption that the war will end in victory. The subject we are to consider, then, is the relationship of the English-thinking peoples during the conflict, and their joint responsibilities in the difficult days that will follow it. A CANADIAN-AMERICAN No talk on such a subject is worth listening to unless the audience knows the background and fundamental beliefs of the speaker. No human statement stands alone; behind and beside and within it are the ideals and the bias of the man who makes it. Because I am a stranger to most of you, I am constrained to talk about myself before I talk about more important matters. The review may be profitable, not because of the subject, but because it may illustrate the evolution of an attitude toward England.

Jan 1, 1941

By N. Kubo

Sumitomo Toyo Copper Smelter and Refinery was commenced in 1971, and its production capacity of sulfuric acid was 550tpd at the beginning. In 2001 Toyo Copper Smelter and Refinery projected to expand its copper production capacity to 450,000tpy, and now the project is still in progress. To achieve this expansion project, 4,000tpd of sulfuric acid production capacity is necessary to the acid plant. So as a part of this project, the construction of the new converting and absorbing line and the improvement of the existing converting and absorbing line were carried out from 2001 until 2005. Then the production capacity of these 2 lines has already reached the target, 4,000tpd of sulfuric acid. Moreover, at the design of the new line, we adopted several latest technologies and materials in order to construct the world's leading acid plant. Basing on the operation performance of the new line, we have improved the existing line in 2005. Both of these 2 converting and absorbing lines are working quite well and contribute to big energy saving and excellently stable operation. Cu2007

Jan 1, 2007

By Lyall J. Lichty

THE property of New Calumet Mines, Limited, is on Calumet island, in the Ottawa river, about sixty-six miles northwest of Ottawa. Lead and zinc orebodies were discovered here in 1893. A gravity concentration plant was built in 1912 but was not a success metallurgically, and the plant was later destroyed by fire. A programme of diamond drilling on the property, started in 1937 and continuing to 1942, indicated ore reserves amounting to 1,300,000 tons averaging 2.75 per cent lead, 8.82 per cent zinc, and 0.041 oz. gold and 6.24 oz. silver per ton( l ). These orebodies have been developed underground by cross-cutting and drifting from a three-compartment vertical shaft, sunk to a depth of 745 feet. 'The ore is a contact metamorphic deposit occurring in rocks of the Grenville series, on or near the contact between biotite gneiss and an overlying calcareous amphibolite(2,3). It consists chiefly of iron-bearing sphalerite, galena, pyrrhotite, pyrite, and minor amounts of chalcopyriteand argentite. The gangue minerals closely associated with the ore are calcite, quartz, and various lime-silicate minerals.

Jan 1, 1945

By G. Q. Liu

"The application of oxygen-enriched cyanidation to three Canadian gold ore samples has been investigated. The results showed that the use of oxygen can improve gold dissolution kinetics, reduce grinding time, and lower cyanide and lime consumptions. To obtain the same gold extraction, the required cyanide leaching time was reduced from 48 hours in slurry containing 8 ppm O2 to 12 - 24 hours in 20 ppm O2 slurry. Reagent consumptions were reduced by 23 - 37% for cyanide and by 35 - 54% for lime. There was little advantage to further increasing the dissolved oxygen to 32 ppm from 20 ppm. Gold extraction from the +200 mesh fraction improved 4 - 14% in oxygen-enriched slurry. A general kinetic model derived from the cyanidation of three ore samples can be described by the following equation: <equation>where E is the gold extraction (%) at time t (hours), EI is the ultimate gold extraction (%) , and &apos;P and k are constants depending on cyanide concentration, level of dissolved oxygen, and the characteristics of the ore samples. Comparative studies of conventional carbon adsorption and carbon adsorption in oxygen-enriched slurry have also demonstrated that oxygen enrichment resulted in more favourable conditions for gold adsorption."

Jan 1, 1995

By T. Motegi

Semisolid casting provides grain refinement of the cast structure and prevents macro-segregation. The conventional semisolid slurry is obtained by electromagnetic or mechanical stirring. In our process, the magnesium alloy (AZ31) slurry is made using an inclined cooling plate instead of the conventional methods. The slurry obtained is cast into a twin-roll caster and makes a continuous sheet of 2 or 3 mm thick. The most important factors that influence the sheet casting are the casting temperature and twin-roll speed.

Jan 1, 2007

By Daniel B. Leznoff

The cyanoaurate anions [Au(CN)2]- and [Au(CN)4]- are shown to be useful building blocks for synthesizing supramolecular coordination polymers. For the gold(I) unit, aurophilic interactions often increase the structural dimensionality of the system and can impart increased thermal stability to the metal-polymers produced. A series of polymers of the form M[Au(CN)2]2(Ligand)x have also been prepared and show large colour changes upon changing the ligand, thus illustrating a sensor-type application. Both building blocks can mediate significant antiferromagnetic and ferromagnetic interactions between transition-metal centres in the polymers. For the gold(III) unit, no metal-metal interactions are observed, although weak Au-N(cyano) interactions control the intermolecular packing. Several structural examples of cyanoaurate-based coordination polymers are presented, including 2-D and 3-D arrays and a supramolecular square.

Oct 1, 2003

By L. Bichler, A. Siebert-Timmer

In this research, novel YSZ ceramics doped with 5 mol% Nd2O3 were manufactured via Spark Plasma Sintering (SPS) process. The sintered Nd2O3-YSZ ceramics were subjected to a static supercritical water environment at a temperature and pressure of 400 °C and 31 MPa, respectively. The weight loss and microstructure development of the sintered ceramic before and after exposure to supercritical water was studied. The results suggested that Nd2O3 addition significantly improved the degradation resistance of the YSZ ceramics. This was attributed to the improved phase stability of the 5 mol% Nd2O3-YSZ ceramics, since X-ray Diffraction (XRD) studies showed that the cubic stabilized matrix in these ceramics was retained after exposure to supercritical water. In comparison, pure YSZ ceramics exhibited a rapid degradation behavior as well as a phase change.

Jan 1, 2014

By J. W. M. Porritt, K. C. Cheng

Knowledge of radon emanation rates from uranium-bearing rocks is essential to the design of mine ventilation systems for uranium mines. Measurements of equilibrium ratio between radon and its daughters in mine air are important for a better control of mine radiation conditions. The concentrations of radon and daughters were monitored at cut-and-fill stopes in the Beaverlodge Mine of Eldorado Nuclear Ltd. during all phases of the mining cycle. The radon emanation rates of ore and rock samples were measured at the laboratory and the results were compared with in-situ emanation tests in an isolated ore drift. Samples of backfill solution, backfill drainage and ground seepage water were measured [or radon and analyzed for radium and uranium. The results showed that discharges of backfill solution and daily shift-end blasts were the two major sources for a rapid release of radon gas in the ventilation air. Other mining operations, such as drilling, mucking, etc., contributed little effect on radon release to the mining environment. Radon emanation rates of the Beaverlodge are samples ranged from 13 x 10-18 to 600 X 10-18 Ci/cm2/ sec and that of waste rock samples from 0.54 x 10-18 to 13.4 X 10-18 Ci/cm2/sec. The in-situ emanation rate of mine walls with ore-to-rock ratios of 1 to 7 was 60 x 10-18 Ci/cm2/sec. The average equilibrium ratio of radon and its daughters in stapes was 32.6%. Under a normal ventilation condition, the average background levels of radon concentration in cut-and-fill stopes ranged from 13 to 80 pCi/L. The discharges of backfill solution during backfill operations at 100 tons solids per hour released approximately 1.8 x 106 pCi/min of radon and elevated radon concentration in stapes 2 to 5 times above the background levels.

Jan 1, 1981

By Charles S. Ney

"THE WRITER'S acquaintance with Kootenay King mine is limited to a brief geological excursion in the vicinity. This paper has been compiled largely from maps of J. Sullivan, mine geologist in 1952, kindly made available to the writer by Transcontinental Resources; a 1942 private report by W. L. Brown; and personal communications with J. Sullivan. Remarks on regional geology, and the comparison with Sullivan mine, are specifically the writer's.The Kootenay King mine is situated in the westernmost range of the southern Canadian Rockies at an elevation of 7,300 feet. From the Sullivan Mine at Kimberley, B. C., it lies 19 miles due east. Six miles of this distance are represented by the pronounced topographical and structural gap of the Rocky Mountain Trench. Mineral claims were locat-ed in the area prior to 1898. The deposit was first seriously explored in the late 1920s, and a small orebody was then outlined and developed. Mining and milling were undertaken in 1951.52. The orebody, amounting to about 14,000 tons, was mined out, and no significant new ore was revealed.The orebody is a replacement of dolomitic argillite by fine-grained galena, sphalerite, and pyrite. The sulphides are finely laminated in the direction of bedding, following out minor folds faithfully. The grade of ore estimated from diamond drill holes (W. L. Brown, 1942) was 11 ·I per cent zinc, 11 ·I per cent lead, and 3·8 ounces per ton of silver. The mineralized zone extends about 250 feet horizontally, 160 feet vertically, with a width of six to twenty feet.General GeologyThe country rocks are sediments of the Aldridge formation of late Precambrian age. For several thousand feet stratigraphically above and below the mine, the formation consists mainly of thinly laminated argillite and siltstone. Several horizons contain appreciable carbonate. About 2,800 feet stratigraphically below the mine, predominantly dolomitic beds mark the top of the underlying Fort Steele formation. The medium-bedded fine quartzites, which characterize about 10,000 feet of the Middle Aldridge in the Purcell range, have a restricted development amounting to only 2,000 feet in the Rocky Mountains. This member is about 2,200 feet above the mine horizon."

Jan 1, 1949

By Burden of Occupational Cancer in Canada Project Team, Demers P. A., Kim J., Arrandale V. H., Jardine K.

"In 2012 diesel engine exhaust (DEE) was classified as a human carcinogen by the International Agency for Research on Cancer (IARC) and is one of the most common workplace carcinogens internationally. We estimate that approximately 2.4% of lung cancers (n=560) and a suspected 2.7% of bladder cancers (n=200) are attributable to occupational exposure to DEE annually in Canada. High levels of exposure to DEE in mining results in a disproportionate number of cancers in this sector (approximately 220 lung and 20 suspected bladder cancers annually). These could be prevented by reducing the number of workers exposed and level of exposure. KEYWORDS Bladder cancer, Diesel engine exhaust, Economic burden, Lung cancer, Mining, Occupational cancer, Prevention, Regulation INTRODUCTION Diesel engine exhaust is a complex mixture of gases and particulates containing known and suspected carcinogens such as benzene, polycyclic aromatic hydrocarbons (PAHs), and metals. Approximately 900,000 Canadians are exposed to diesel engine exhaust at work, making it the most prevalent occupational lung carcinogen in Canada (CAREX Canada). Diesel engine exhaust is recognized as one of the most common workplace carcinogens in the world, but its classification as a human carcinogen by the International Agency for Research on Cancer (IARC) was relatively recent. In 2012, after decades of mounting evidence, diesel engine exhaust was upgraded from a probable (IARC Group 2A) to a definite human carcinogen (IARC Group 1) (IARC, 2014). The IARC evaluation was based on strong evidence in humans for an increased risk of lung cancer, as well as strong evidence in animal studies. The key human evidence considered by IARC was from epidemiologic studies of workers in truck transportation, rail transportation, and mining industries, where the use of diesel engines is widespread. These studies provided strong sufficient evidence for an increased risk of lung cancer, as well as limited evidence for bladder cancer. The human studies used particulate matter, generally measured as elemental carbon (EC) or total carbon, as a surrogate for diesel engine exhaust to assess the risk associated with level of exposure. The animal studies reviewed by IARC showed sufficient evidence for cancer with exposure to whole diesel exhaust and the particulate matter fraction of diesel exhaust, but not for the gas phase components."

Jan 1, 2019

By K. N. Subramanian, H. Kanduth

"It is well known that chalcopyrite can be dissociated into simple sulphides by heating with elemental sulphur at about 475°C:CuFeS2 + S -> CuS + FeS2Experimental work was undertaken to determine whether this ""activation"" could be used to advantage in the selective leaching of copper from chalcopyrite concentrate.A method of treating copper concentrate with molten sulphur was developed and the activated product was leached in dilute sulphuric acid using oxygen, ferric iron or manganese dioxide as the oxidant. The object was to obtain a solution suitable for electrowinning with minimal purification, but it was impossible to obtain rapid extraction of copper without simultaneously dissolving a large proportion of iron. This was attributed to the fact that some of the copper was present as a low iron-copper sulphide (idaite) and that the pyrite formed during the ""activation"" step was more easily oxidized than natural pyrite."

Jan 1, 1973

By Jean-Yve Tremblay, Michel Prud'homme

"Industrial minerals include a group of more than fifty minerals which are marketed into almost all the sectors of industry; they are the backbone of many manufacturing industries. Table I shows major end-uses for industrial minerals in manufacturing sectors. At Energy, Mines and Resources, industrial minerals are divided in three major categories: (I) agro chemicals and chemicals, (2) construction mineral s, and (3) ceramics and specialty minerals. A listing of the major groups of minerals is shown in Table 2. Agro-chemicals and chemicals are sold on the basis of their chemical content and purity. Construction minerals or structural minerals are distinguished by their performance as low cost and bulky commodities. Ceramics and specialty minerals are performance-specific and are sold for their property on imparting functions on end-products. Industrial minerals have unique characteristics that are useful in many stages of processing; from crushed size to micronized fillers a single mineral ca n serve a broad range of industries because of its intrinsic properties."

Jan 1, 1988

By T. Nagasaka, T. Miki

Suppression of CO2 and waste such as slags discharged from iron- and steelmaking processes are some of the typical major issues for the protection of global environment and sustainable growth of steelmaking industry. Utilization of active phytoplankton growth will be one of the best options to stabilize and suppress carbon dioxide at high-efficiency. Inorganic minerals such as C, 0, N, Si, P and Fe are necessary for phytoplankton multiplication. It is crucial for supply of nutrition into seawater effectively for phytoplankton multiplication to understand the dissolution behavior of some elements from steelmaking slags into seawater. The morphology of the precipitated phases in steelmaking slags during cooling period was investigated in the present work. The dissolution behavior of some elements from steelmaking slags into artificial seawater has also been studied. The effect of nutrient dissolved into seawater on phytoplankton multiplication, some examples of marine structure made from steelmaking slag, and estimation of CO2 fixation amount by marine phytoplankton are also discussed.

Jan 1, 2004

By H. Helmstaedt, P. Thurston, R. Harrap

"Evolution of the continental lithosphere over Earth’s 4.6 billion year history is one of the fundamental questions of geoscience. Much of the Earth’s present-day continental crust formed during the first 2 billion years, the Archean eon, of the planet’s lifetime and thus, Archean processes of lithospheric formation must be studied in order to address this question. Until recently, the processes of Archean lithospheric evolution were thought to be fundamentally different from present-day plate tectonic processes. However, subsequent evidence suggests that the growth of Archean continents may be explained in terms of modern tectonic accretionary tectonics similar to those presently operating in the southwest Pacific region. The evidence supporting this hypothesis was compiled largely by Canadian geoscientists working in the Superior Province of the Canadian Shield in northwestern Ontario, over the past 15 years. Study of Archean rocks is also economically important because the Archean rocks of the world, although comprising only a relatively small fraction of the exposed continental crust, contain much of the world’s mineral wealth, including more than half of the world’s gold, as well as significant base metal reserves. Furthermore, the vast majority of primary economic diamond deposits are derived from the lithospheric roots beneath Archean cratons.The LITHOPROBE Western Superior Transect is located within the western part of the Superior Province in northwestern Ontario (Fig. 1). The Superior Province is the largest and best exposed Archean crustal block in the world and forms the nucleus of the North American continent. The internal structure of the Superior Province records a history of the processes that formed the earliest lithospheric elements of the Earth into cratons, thus providing an ideal laboratory for investigating early crustal evolution. The Western Superior Province is characterized by a regional pattern of alternating, 100 km to 200 km wide geological belts (Fig. 2). The observed geologic relationships between and within these subprovinces have been explained in terms of a modern tectonic model of terrane accretion. Oceanic floor, volcanic island arcs, oceanic sediments and continental fragments were accreted successively from north to south against the southern margin of a cratonic nucleus (North Caribou terrane, Fig. 2) which grew steadily in size with the arrival of new terranes through geologic time. If this model is correct, it suggests that the tectonic processes operating today have been active without major variation over the past 3 billion years."

Jan 1, 1998

By R. A. L. Drew, J. P. Immarigeon, F. Jalilian, M. Jahazi

In the present work TLP bonding of Inconel 617 is investigated. The influence of the main processing parameters i.e. time and thickness of the interlayer were studied with optical and scanning electron microscopy. Boron containing interlayers with two different thicknesses were used and the influence of various holding times from 5 min to 24 hours on the microstructure of the bond region was investigated. The results indicated that, for the testing temperature of 1065°C and holding times above 2 hours with an interlayer of 25.4 microns thick no liquid phase was observed. The same phenomenon occurred only after 6 hours for a 76.2 microns thick interlayer. Precipitate growth started at grain boundaries and continued inside the grains. The composition, size and morphology of the precipitates were studied using electron microprobe analysis. No noticeable changes were observed in the grain size of the base metal with increasing holding times.

Jan 1, 2004

By Q. Dong, S. A. Nightingale

An investigation has been carried out to assess the effects of an applied voltage on the dissolution rate of MgO refractory in a steelmaking like slag. In this study corrosion results obtained from dip tests using a dense direct bonded MgO refractory in a CaO-SiO2-Fe2O3-FeO-MgO slag are presented. These results demonstrate that the application of a voltage across a dense MgO refractory-slag interface can change the rate of refractory dissolution. For the slag composition used and the voltage range tested, it was found that a maximum corrosion rate was obtained at a voltage setting of -0.45V. The results of this investigation have been explained in terms of voltage affects on Marangoni (interfacial tension induced) stirring and its effect on the MgO dissolution reaction that is at least partly controlled by mass transfer in the slag.

Jan 1, 2004