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By Dirk Verhulst

The Altair Hydrochloride Pigment Process is a new ?third route?, besides the established high-temperature chloride process and the older sulfate process, to manufacture TiO2 pigment from ilmenite ore. It has been tested at a scale of 5 t/day feed. The ore concentrate is digested in high-acid, high total chloride solution (+/- 39% Cl). Titanium and iron both go into solution. Iron is separated as FeCl2 crystals after reduction and cooling. Titanium is transferred by solvent extraction into a purified, high-Ti stream. It is spray-hydrolyzed to produce a TiO2 hydrate and further calcined with additives into high-quality pigment. HCl solutions generated by pyrohydrolysis and spray hydrolysis are treated by pressure-swing distillation to regenerate HCl gas for re-injection into the digestion reactor. All chloride streams are recycled. Recent work has concentrated on optimization, particularly in 3 areas: - Solvent extraction: a new organic mixture, including a new diluent, makes it possible to work at room temperature, to avoid TiO2 hydrolysis problems and to improve phase disengagement and impurity separation. - Pigment finishing: a systematic study of the parameters involved, followed by long runs in the best conditions confirm pigment quality. - Flow sheet optimization: innovative modifications of the conditions of spray hydrolysis and pyrohydrolysis, combined with re-routing of streams achieve significant energy savings. A 100 t/year pilot plant including these features as well as other process improvements is under construction.

Jan 1, 2006

By Keith E. Dyas, John Nelson, Ronald T. Johnson

GENERAL DESCRIPTION The Bruce mine of Cyprus Mines Corp. is located in Bagdad, AZ. The mining method used is open cut-and-fill. Of the annual production of 81 647 t (90,000 st), approximately 83% is taken from load-haul-dump (LHD) stopes and the balance from slusher stopes. All ore is produced from the area between the 1250 level and the 2300 level. The average travel time from the shaft pocket to the stope is approximately 5 min. GENERAL ORE BODY REQUIREMENTS AND LIMITATIONS Size, Shape, and Dip The Bruce ore body occurs in quartz-sericite schist with Dick rhyolite on the footwall and andesite on the hanging wall. Diabase dikes are found in the hanging wall; there is also a dike coming off the footwall and crosscutting the ore body. All of the rock types are of the Precambrian Yavapai series and have been subjected to regional metamorphism. A composite of the ore body is given in Fig. 1. The deposit is of massive sulfides occurring as a steeply dipping replacement body. On the upper levels the ore is veinlike with widths from 0.6 to 4.6 m (2 to 15 ft), dipping at 1.4 to 1.5 rad (80° to 85°). On the lower levels the ore is dipping from I to 1.2 rad (60° to 70°) with widths from 3 to 16.8 m (10 to 55 ft). The strike length varies between 107 to 183 m (350 to 600 ft). The rhyolite footwall generally has a knife-edge contact with the massive sulfides. The exceptions to this are the upper levels where there is a 1.5 to 3 m (5 to 10 ft) band of silicified sericite schist between the sulfides and the rhyolite. In the southern part of the ore body the hanging wall is tuffaceous andesite and andesite. In this area the contact is generally sharp and easy to follow. However, to the north there is a large chlorite schist zone that crosscuts the bedding and comes in contact with the massive sulfides. This is apparently due to hydrothermal alteration of the andesite. The chlorite schist is highly mineralized with chalcopyrite and pyrite and quite often forms economic pockets of ore. In the massive sulfides the chief ore minerals are sphalerite and chalcopyrite. Pyrite is the predominant sulfide with considerable pyrrhotite throughout. Bright arsenopyrite ouhedrons in fine grain massive sulfides are quite common. Occasionally small amounts of galena are seen, usually near the foot or hanging wall contacts. On rare occasions tennanite is associated with massive arsenopyrite. Minor amounts of quartz, calcite, and un¬replaced remnants of sericite schist occur, but essentially pyrite is the gangue in which the ore minerals occur. The ore values are in excess of 3.5% copper and 12.5% zinc with some silver and rare gold as byproducts. Ground Conditions The massive sulfides are generally self-supporting. One exception is in the 1850 stope where the ore body is 9 to 11 m (30 to 55 ft) wide and 152 m (500 ft) long. There are flat to shallow dipping slips and seams in the ore, creating extremely blocky ground. For support, old 25.4-mm (1-in.) hoist ropes were installed tensioned to 27 t (30 st), and then cement grouted over the entire length in longholes [14 to 15 in (40 to 50 ft) in length) drilled on 3-m (10-ft) centers from the level above. This has tied the formation together very successfully and virtually eliminated the blocky ground condition. Both the hanging wall and footwall are quite shaley in some areas. Reasons for Adopting Trackless Open Cut-and-Fill Methods First, any method other than open cut-and-fill would have caused too much dilution. The use of rubber-tired mining equipment in the pro¬duction stopes requires a footwall ramp. The inclines in ore will be mined out, so this ramp in the footwall will provide access to and from the stopes (Fig. 2). This incline is very expensive, but necessary to convert existing stopes to LHD mining. 'The final cost of ore mined by the LHD machines has not been determined. As of 1972, tons per manshift in the 2150 stope-the only one to complete a full cut-had increased from 7.58 t (8.36 st) to 12.83 t (14.14

Jan 1, 1982

By W. H. Patterson

The history and experience of early companies in the Islands is illustrated by the typical transactions of Trans-Western from 1959 to date. Trans-Western had entered into farmout agreements with companies strong enough to carry out at least the required minimum exploratory work and then such development as might be warranted. The farmee companies were required to make deposits to guarantee work performance during the first period of validity, i.e. the first 3 years of the 12-year life of the permits, and at the rate of 5 cents per acre. At that time, a good deal of geology was available, as a result of extensive exploration that had been carried on by the Geological Survey of Canada and other geological enterprises, with field parties travelling over and camping on all of those Islands. Trans-Western's farmees then selected, from Trans-Western's priority on 13.5 million acres, what they believed were the lands most prospective of producing large oil and gas discoveries, and, having the right to trim off acreage which they considered less prospective, thereby reducing the acreage of Trans-Western and its farmees to in excess of 5.5 million acres. The farmees then commenced a 3-year program carrying out geological exploration to the required minimum of 5 cents per acre, and with some permanent and many mobile camps.

Jan 1, 1969

By Chengliang Jliang, B. K. Parek, Xuxin Shao

Of the impurities present in phosphate ore, dolomite is the most difficult to remove due to the similar chemical compositions of the impurities and also adsorption of dissolved species of dolomite onto phosphate. A new amphoteric surfactant was found to be a suitable collector for separation of dolomite from phosphate. Flotation results showed that the new amphoteric collector had a high flotation selectivity for dolomite in wide pH ranges. The flotation study of francolite and dolomite in each other's supernatant demonstrated that the dissolved ions had little effect on the selectivity of the new collector, but were detrimental to the flotation separation using sodium oleate as collector. A phosphate concentrate with 35.2% P2O5 with 90% recovery was obtained using 290 g/t of the amphoteric collector from a mixture of francolite and dolomite containing 26.2% P2O5. The rejection of MgO was 81.41%.

Jan 1, 1999

By McDougall I, Claoue-Long J

A combination of high precision 40Ar/39Ar and U-Pb dating has been used to determine the age of hydrothermal minerals and host rocks in a number of Lachlan Fold Belt (LFB) gold deposits in New South Wales, Au4 ralii In particular, this investigation demonstrates that the UAr/ Ar technique of K-Ar dating can be used to determine the timing of mineralization in Palaeozoic systems.A close temporal link between mineralization and Late Ordovician to Early Silurian magmatism is indicated by the dating work. Hydrothermal sericite from the Goonumbla p8rph gy Cu deposit and Glendale Au prospect yieldsAt/ Ar step heating ages between 437.9 ¦ 1.1 and 441.2 ¦ 1.1 Ma (16), and4 minjrnum age of about 425 Ma has been obtained by Ar/ Ar dating of hydrothermal amphibole from the Browns Creek Au-Cu skarn deposit. Hydrothermal aluniI8 frog the Gidginbung epithermal Au deposit yields reset 44 Ar/ Ar ages of 401.0 ¦ 1.3 to 417.3 ¦ 1.3 Ma (16). U-Pb dating by ion microprobe on magmatic zircons from the vicinity of the Goonumbla and Gidginbung deposits gives ages of 438 ¦ 3.5 Ma (2 6), and 435 ¦ 2.5 Ma (2 (7) respectimly, W a minimum age of 435 Ma has been obtained by Ar/ Ar dating of magmatic phases from volcanic rocks adjacent to the Browns Creek skarn deposit. Magmatic episodes near the Sheahan-Grants gold skarnpost give ages of 479.2 ¦ 1.1 and 467.9 ¦ 4o1 by 'Ar/ 9Ar dating of magmatic amphibole. Most Ar/3yAr age spectra show the effects of partial Ar loss at between 360-420 Ma, probably due to heating caused by granitoid emplacement.The radiometric dating work in this paper suggests a restricted metallogenic epoch in the Late Ordovician-Early Silurian LFB, NSW, of similar duration to that found in the Andean margin and the western Pacific island arcs around the Pacific Rini.

Jan 1, 1990

By J. H. Swisher

The solubility of sulfur and rate of solution of sulfur in pure Lron were measured in H2S + H2 and H2S + H2 H2O gas mixtures. The solubility and diffusivity of sulfur at 1410°Care 0.13 pet S and 1.0 x 10-5 sq cm per sec, respectively. The solubility iS the same, but the rate of sulfurization is slower in the presence of H2O in the reacting gas. Under these conditions, the over-all rate is controlled jointly by a slow surface reaction and by solid-state diffusion; the mechanism for the surface reaction has not been identified. KNOWLEDGE of the behavior of sulfur in solid iron is desirable for the metallurgy of such products as free machining steel, where a high sulfur level is required, and inclusion-free high-strength steels, where the sulfur specifications are very low. The present investigation was undertaken to check previously reported values for sulfur solubility and diffusivity in 6 iron, and to study the poisoning effect of chemisorbed oxygen on sulfurization kinetics in H2-H2S-H2O gas mixtures. All of the experiments were performed at 1410°C. The thermodynamic behavior of sulfur in 6 iron was the subject of a paper by Rosenqvist and Dunicz.' The sulfur solubility at 1400" and 1500°C was determined by equilibrating pure iron specimens with H2-H2S gas mixtures. The maximum solubility of sulfur in 6 iron was alsc determined by Barloga, Bock, and parlee2 by reacting iron wires with sulfur in sealed capsules. In another investigation, the diffusion coefficient of sulfur in 6 iron at temperatures up to 1450°C was measured by Seibel.3 The method used was to measure sulfur concentration profiles in diffusion couples containing radioactive sulfur EXPERIMENTAL Apparatus. A vertical resistance furnace wound with molybdenum wire and containing a recrystallized alumina reaction rube was used for the experiments. The hot zone in the furnace was approximately 2 in. long with a temperature variation of ±3oC. The hot zone temperature was automatically controlled to within ±2°C, and the test temperature was measured with a pt/Pt-10 pet Rh thermocouple before and after each experiment. Flow rates of the reacting gases were obtained using capillary flow meters. Materials. The source of H2S in the gas train was a premixed cylinder containing 5 pet H2S in H2. This mixture then was diluted with additional hydrogen and argon. In some experiments, water vapor was introduced by passing hydrogen and argon through a column containing 10 pet anhydrous oxalic acid and 90 pet oxalic acid dihydrate. The vapor pressure of water above this mixture is well-known.4 Argon was used as a diluent to minimize thermal segregation of H2S in the furnace5 and to reach higher H2O:H2 ratios than could be obtained in mixtures of H2 and H2S alone. Argon was purified by passage over copper chips at 350°C and subsequently over anhydrone. Hydrogen was purified by passage over platinized asbestos at 450°C and then over anhydrone. The H2-H2S mixture was purified by passage over platinized asbestos and then over P2O5. The specimen stock was made by melting and vacuum-carbon deoxidizing electrolytic "Plastiron" in a zirconia crucible. The principal impurities are listed in Table I. In some of the equilibrium experiments, six-pass zone-refined iron was used to minimize impurity side effects. This zone-refined iron had a total impurity level of about 25 ppm. Procedure. Specimens were annealed in hydrogen for a period of at least 2 hr at the beginning of each experiment. The specimens were held in the reacting gas for times varying between 10 min and 17 hr, and cooled to room temperature in a water-cooled stainless-steel block at the bottom of the furnace. The pH2S/pH2 ratios reported are those for gas equilibrium at 1410°C. Calculations based on available thermodynamic data8 showed that the only other gaseous8 species that formed in significant amounts in the furnace were S2 and S. Even when water vapor was introduced into the gas mixture, the concentrations of SO2, SO, and so forth, were negligible. The initial partial pressure of H2S was therefore corrected for its partial dissociation to S2 and S in determining the equi-

Jan 1, 1968

By Melinda Channel, Alan W. Weimer, Jonathan R. Scheffe

"There is a need to develop cost effective renewable energy processes for the production of clean fuels that can simultaneously mitigate the U.S. energy/global environmental security issue. If H2 can be obtained cost effectively via the splitting of water using concentrated sunlight, then it’s possible to operate a fuel cell using renewable H2 or to synthesize other fuels based on renewable H2 for generating electricity or for running internal combustion engines. For example, H2 can be reacted with sequestered carbon dioxide (CO2) to produce syngas (H2/CO) via reverse water gas shift (RWGS), i.e. H2 + CO2 ? CO + H2O. The syngas can be catalytically methanated to form synthetic natural gas (SNG) or it can be catalytically reformed to produce liquid fuels such as “green” gasoline via the MTG process (syngas? methanol ? gasoline). The desert SW United States is home to world class sunlight. Fundamental ferrite thermodynamics will be reviewed, an example of the beneficial effect of ferrite surface area on reaction kinetics will shown, and process economics will be investigated for a 100,000 kg/day facility to produce H2.Introduction and Background ThermodynamicsSpinel ferrites of the form MxFe3-xO4, where M generally represents Ni, Zn, Co, Mn, or other transition metals, have been shown to be capable of splitting water according to the two step cycle shown below:MxFe3-xO4 + solar thermal energy ? xMO + (3-x)FeO + 0.5 O2 (1)xMO + (3-x)FeO + H2O ? MxFe3-xO4 + 2H2 (2)This is an inherently clean and sustainable process, as the only net inputs are solar energy and water, and the net outputs are hydrogen and oxygen. Ferrite water splitting cycles are advantages compared to other high temperature water splitting cycles, such as the ZnO/Zn and Mn2O3/MnO cycles, because thermal reduction has been demonstrated at significantly lower temperatures[1, 2]. As a result, overall efficiency may be increased due to the fact that radiation losses increase as the fourth power of temperature, and material considerations for reactor design should be more flexible. Additionally, cycle repeatability has been demonstrated with relative ease as compared to other thermochemical cycles [3-6]. However, the amount of hydrogen per mole that is generated is significantly less than for other high temperature thermochemical cycles due to the fact that only Fe3+ is capable of being reduced at the temperatures of interest[6]. In addition, water oxidation kinetics appear to be very slow, likely due to diffusion or surface area limitations created by near surface oxidation [6, 7]."

Jan 1, 2010

By P. H. Dudley

A quarter of a century of service of steel rails on our oldest railroads, many of which have changed their standard sections three or four times, has furnished, and is furnishing, excellent opportunities to study their wear and behavior in the track. Such experience is valuable for the design of new sections, now required to meet the constantly increasing severity of railroad service. Before presenting the new sections for consideration, I will briefly call attention to some features of past experience. For convenience of study, rails may be separated according to their weight and height into four groups, viz.: 1. Hails weighing per yard from 52 to 60 pounds, and 34 to 4 inches high. 2. " " " " " 60 " 72 " " 46 to 44 " " 3. " " " " " 72 " 90 ' 41/8 to 5 4. " " " " " 85 or more " " over 5 " I Experience in this country is confined mainly to sections in groups Nos. 1, 2 and 3. • During the past few years I have had the opportunity to run my car over many thousands of miles of railway laid with the principal sections in use, and to obtain diagrams showing their deflections, permanent set, and, in a great measure, their manner of wear. The First Group.—The first steel rails imported, and those manufactured here, were light sections—included in the first group—and many of them, being rolled in rolls used for rolling iron sections, have pear-shaped heads, 2 3/8 to 2 1/2 inches wide, the base being heavy and from 1/4 to 1/2 inch narrower than the height. These rails were laid upon ties of solid timber, at least 8 inches face, spaced 2 feet from center to center. The moments of inertia of these rails were low, only ranging from 8 for the lightest sections to 12 for the heaviest. The deflections were, of course, great; but the quality of the metal was excellent. It was physically hard and

Jan 1, 1890

By K. E. Yassin, A. Yehia, M. Amar

Phosphate fines (size ≤ 45 μm), from the Red Sea Region, Egypt, were subjected to beneficiation process to recover the phosphorite grains from such fines. The sample is characterized by low P2O5 content (18.78%) associated with gangue minerals such as silica (22.77% SiO2) and carbonate (2.01% MgO) indicating its low grade. Phosphate pre-concentrate was prepared by gravity separation, using Falcon, where 63.37% of the phosphate, with 24.94% P2O5, 1.46% MgO, and 10.54% SiO2, was firstly recovered reducing the mass flow to the subsequent beneficiation process. However, the gravity tailing was the feed for the reverse phosphate flotation using bench scale column flotation where oleic acid was used as a carbonate gangue collector and amylase enzyme as a phosphate depressant. Under the appropriate flotation conditions (0.1% amylase, 5·10−4 mol/dm3 oleic acid, and temp. 30 °C), phospho-concentrate assaying 0.61% MgO, 13.14% SiO2, and 27.85% P2O5 with a P2O5 recovery of 55.45%, was finally obtained without the use of expensive depressants, e.g., phosphoric acid or sodium silicate. A tentative flow sheet for the whole process was postulated.

By Walter Crafts, C. M. Offenhauer

IN the course of study of the heat-treatment of low-alloy steels, the behavior of alloy carbides at subcritical temperatures was found to vary from that indicated by published investigations. In order to establish the ranges of formation of carbides in low-chromium steels, a series of steels containing up to 0.60 per cent carbon and 7.5 per cent chromium has been investigated with respect to the type of carbide formed after quenching and tempering at sub-critical temperatures. The types of carbide formed as products of austenite transformation to pearlitic and pseudomartensitic structures have also been determined. There have been numerous investigations of the carbides in chromium steels and diagrams of the iron-chromium-carbon system.' Westgren, Phragrnén and Ne-gresco2 identified the following carbides in chromium steels: Cementitc............ Fe3C (containing up to about 15 per cent Cr) Trigonal carbide...... Cr7C3 (containing up to about 55 per cent Fe) Cubic carbide........ Cr4C (or Cr23C6) (con- . taining up to about 25 per cent Fe) Orthorhombic carbide , cr3c2 (containing only a few per cent Fe) The most complete information on the iron-chromium-carbon system was supplied by Tofaute, Sponheuer and Bennek3 and by Tofaute, Küttner and Büttinghaus,4 By means of dilatometric and microscopic stzdies, sections of the diagram were established. This diagram showed the presence of the special carbide CI7C3 in steels containing about 2.5 per cent to 12 per cent chromium in low-carbon steels and from about 5 to 20 per cent chromium in I per cent carbon alloys from A1 to room temperature. The present investigation has shown that a carbide inversion from Fe3C to Cr7C3 occurs in chromium steels containing more than about I per cent chromium after hardening and tempering at subcritical temperatures above about 500°C. The type of carbide observed to be more stable in quenched and tempered specimens was also found to be produced by direct austenite transformation in corresponding ranges of temperature and composition. Experimental Procedure The steels used in these experiments were made in magnesia-lined crucibles in high-frequency furnaces and were poured into 2-in. ingots. The ingots were forged into I-in. round bars, and all heat-treatments were conducted on specimens of this section size. Sections of the bar stock 8 in. long were hardened in air, oil or water, depending on the composition, after heating to a temperature sufficiently high to dissolve the carbides. The low-carbon and low-chromium steels were not entirely martensitic after quenching, and contained some ferrite and pseudomartensite. No pearlite was observed in the microstructures after quenching. The quenched bars were cut into

Jan 1, 1942

By Walter Crafts, C. M. Offenhauer

IN the course of study of the heat-treatment of low-alloy steels, the behavior of alloy carbides at subcritical temperatures was found to vary from that indicated by published investigations. In order to establish the ranges of formation of carbides in low-chromium steels, a series of steels containing up to 0.60 per cent carbon and 7.5 per cent chromium has been investigated with respect to the type of carbide formed after quenching and tempering at sub-critical temperatures. The types of carbide formed as products of austenite transformation to pearlitic and pseudomartensitic structures have also been determined. There have been numerous investigations of the carbides in chromium steels and diagrams of the iron-chromium-carbon system.' Westgren, Phragrnén and Ne-gresco2 identified the following carbides in chromium steels: Cementitc............ Fe3C (containing up to about 15 per cent Cr) Trigonal carbide...... Cr7C3 (containing up to about 55 per cent Fe) Cubic carbide........ Cr4C (or Cr23C6) (con- . taining up to about 25 per cent Fe) Orthorhombic carbide , cr3c2 (containing only a few per cent Fe) The most complete information on the iron-chromium-carbon system was supplied by Tofaute, Sponheuer and Bennek3 and by Tofaute, Küttner and Büttinghaus,4 By means of dilatometric and microscopic stzdies, sections of the diagram were established. This diagram showed the presence of the special carbide CI7C3 in steels containing about 2.5 per cent to 12 per cent chromium in low-carbon steels and from about 5 to 20 per cent chromium in I per cent carbon alloys from A1 to room temperature. The present investigation has shown that a carbide inversion from Fe3C to Cr7C3 occurs in chromium steels containing more than about I per cent chromium after hardening and tempering at subcritical temperatures above about 500°C. The type of carbide observed to be more stable in quenched and tempered specimens was also found to be produced by direct austenite transformation in corresponding ranges of temperature and composition. Experimental Procedure The steels used in these experiments were made in magnesia-lined crucibles in high-frequency furnaces and were poured into 2-in. ingots. The ingots were forged into I-in. round bars, and all heat-treatments were conducted on specimens of this section size. Sections of the bar stock 8 in. long were hardened in air, oil or water, depending on the composition, after heating to a temperature sufficiently high to dissolve the carbides. The low-carbon and low-chromium steels were not entirely martensitic after quenching, and contained some ferrite and pseudomartensite. No pearlite was observed in the microstructures after quenching. The quenched bars were cut into

Jan 1, 1942

By Danny A. Riley, James R. Sanger, Hani S. Matloub, Michael Agresti, David Rowe, Lin-Ling Zhang, Yuhui Yan, Paula Galaviz, Judith Marchant-Hanson, Ji-Geng Yan

Until now there has been controversy about which tests should be performed to diagnose early Hand-Arm Vibration Syndrome (HAVS). Initial screening questions, especially about tingling and numbness, routinely given to patients prior to examinations proved to be a very important tool in the diagnostic process1, 4. However, standardized tests that are simple, quick, valid and reliable are needed to support a diagnosis of HAVS. Purpose: To find the most valid and reliable tests to diagnose HAVS. Material and Methods Five major tests were performed on Group I and Group II. Group I: Control group of 12 volunteers including students, nurses, secretaries and physicians with no history of using vibrating tools (age 20 to 50y, mean age 38.5y; 5male, 5 female.) Group II: 12 workers (age 17 to 65y, mean age 39y; 9 male, 3 female) were sent by a local trade union with a history of using vibrating power tools on their jobs for varying amounts of time (mean 12.2y, from 0.5 to 35y.) Pre-enrollment survey showed that each had more than 4 complaints commonly associated with use of vibrating tools (including numbness, tingling, weakness, pain, finger color or nail changes, temperature change, and difficulty moving.) 1. Sensory nerve conductive tests: Amplitude and nerve conductive velocity (NCV) were evaluated. 2. Cold Stress-Temperature recovery time tests were done on the index finger of the dominant hand following these steps: Confirm water bath is within 4-5º C. Place the finger temperature probe on pad of the index finger of the dominant hand. Record temperature every 15 seconds. Place subject’s hand in the cold- water bath for exactly five minutes. Record temperature every 15 seconds for ten minutes. 3. Blood test: Venous blood was taken by a 21-gauge needle with the yellow collection tube adapter. S-ICAM, Sera Thrombomodulin, Norepinephrine levels were evaluated by Henderson Research Centre, Canada. 4. Finger Sensory Evaluation: Semmes-Weinstein monofilament test and 2-point discrimination tests were performed on bilateral fingers. 5. Digital blood pressure test: blood pressure was measured in bilateral index fingers. Results 1. Median nerve sensory conductive amplitude from palm to wrist : GI: mean 96 ± 31µm; GII: mean 43± 30µm; for dominant hands. GI vs GII: P<0.001

Jan 6, 2006

Chairman: Mr. R. C. Heers, Project Manager, Kaiser Company, Inc. CHAIRMAN HEERS: Fellows, I can&apos;t say it gives me a lot of pleasure to call this meeting together because I would rather somebody else had the job. I haven&apos;t anything to say this morning and I think the sooner we get started with the fellows that have something to say, the better pleased everybody will be. The first speaker this morning is Mr. John Griffen of the McNally Pittsburgh Company. He has a talk on coal preparation and I am pleased to present Mr. Griffen.

Jan 1, 1947

By R. H. Matjie, J. R. Bunt, A. C. Collins, J. C. van Dyk, C. A. Strydom

South African discard coal fines and K₂CO₃ blends were heated in a laboratory-scale rotary kiln to produce ashes for H₂SO₄ leaching tests. The optimized H₂SO₄ leaching conditions of 6.12 mol.dm³ (M) H₂SO₄, solid to liquid ratios 1:5 and 1:10, and 80°C for 8 hours were used. K₂CO₃ was added to increase the dissolution efficiency of K. The objective was to determine if the Al present in metakaolinite (Al₂O₃.2SiO₂), the Al, K, and Ti in the alumino-silicate glasses, and the Ti in rutile (TiO₂) in the ashes could be selectively dissolved in H₂SO₄. XRF results show that the ashes formed at 700°C dissolved more efficiently (87% Al, 89% K and 23% Ti) compared to the ashes formed at 1050°C. This can be attributed to the presence of Al₂O₃.2SiO₂, K₂CO₃ melt, K₂CO₃ remnants, KAl(SO₄)₂, and K-aluminosilicate glass in these ashes. XRD results indicate that the ashes prepared at 1050°C contained anorthite (CaAl₂Si₂O₈), microcline (KAlSi₃O₈), pseudomullite (Al₂O₃.SiO₂), and silicon spinel (2Al₂O₃.3SiO₂), which are either insoluble or only sparingly soluble in H₂SO₄. These minerals resulted in the lower dissolution efficiencies of Al and K. Based on the high dissolution efficiencies of Al and K for the ashes produced at 700°C, coal fines blended with K₂CO₃ could possibly be utilized as feedstocks for the production of aluminium(III), potassium(I), and titanium(IV) and a sulphate-containing leach liquor. Furthermore, the environmental issues and costs associated with the handling and disposal of large volumes of coal fines will also be resolved.

Aug 2, 2022

By Davi Silva Braga

Controlar o perfil térmico dos fornos de uma planta de pelotização é essencial para se garantir a qualidade das pelotas e manter a competitividade da produção. A medição online de variáveis-chave é restrita devido às condições da planta ou limitações tecnológicas, fazendo-se necessário a utilização de um modelo matemático (Soft Sensor) para estimar essas variáveis e, então, exercer maior controle sobre a qualidade e custos do processo. Através de balanços térmico e mássico, o modelo é capaz de predizer o perfil térmico das pelotas e as perdas, térmicas e mássicas, além de simular mudanças no processo e implicações no consumo de combustível. Com o modelo, observou-se a possibilidade de redução de 5% de perda térmica, resultando em redução de 2% do consumo de combustível, devido à melhora da recuperação de calor da zona 2 do resfriador para a pré-queima 1 do forno grelha. O trabalho foi realizado na planta da Vallourec &amp; Sumitomo Tubos do Brasil (VSB).

Aug 17, 2017

By K. A. Elbarawy

Processing of Egyptian barite ore with a composition of 85.5% BaSO4; 2.75%SiO2;1.56%Fe2O3 and 5.1% Al2O3 was performed with the aim to prepare pure barium salts. The process took place through pelletization-solid state reduction and leaching steps. Each of these steps was optimized. Pure barium sulphate (99% < 0.82µm) and carbonate (99%<0.75µm )were the final products. This article deals with the reduction process that occur whn coal was added to the ore during pelletization in the ratio of 5:1 stoichiometry. Optimum reduction of pellets of 8-12mm in diameter was achieved after 60 minutes at 1050oC and under a rate of 5 lmin-1 of nitrogen atmosphere, where 87.79% of the ore was reduced. The kinetic studies showed that the reduction process could be modeled according to the core mechanism of diffusion control in which the effective diffusivity is based on the surface area of unreacted ore. The activation energy calculated was 92.7 kJmol-1.

Jan 1, 2006

"SUMMARYThe K.M.A. reservoir was discovered to be oil bearing at a depth of 3,719 feet on March 11, 1931. Extensive development, however, was not begun immediately, because the discovery well had a low initial daily oil production, and market conditions for oil were unfavorable. Development of the field progressed slowly for the next 6 1/2 years. In the latter part of 1937, a wildcat well approximately 2 miles southwest of the discovery well was drilled on a magnetometer high and completed with an initial flowing production of 2,016 barrels of 43° A.P.I.-gravity oil in 12 hours. Rapid development of the southwestern part of the K.M.A. field was begun immediately and continued until over 700 wells were drilled and approximately 12,500 acres proved oil productive.Because of the large size of the entire K.M.A. field, this report is limited in scope to the southwestern part only, and the discussion that follows pertains to this area only. The closing date for production statistics is August 1, 1949.The K.M.A. structure is a complex anticline having a maximum closure of 250 feet, and the K.M.A. formation is composed of sediments that grade from limestone through sandy lime and limy sand to sandstone with thin streaks of shale. Two distinct members of the K.M.A. formation, zone I and zone II, are oil productive. Core analyses indicate the average porosity to be 16.5 percent for zone I and 16.1 percent for zone II. A relationship was established from core data, which showed the correlative permeabilities to be 42.1 millidarcys for zone I and 39.5 millidarcys for zone II, whereas the arithmetical averages of the permeabilities were 84 millidarcys for zone I and 216 millidarcys for zone II. Connate water saturations were 17.5 percent for zone I and 20.0 percent for zone II. The porosity-saturation method, using a thickness-correction factor, was employed to calculate the volume c 168.1 million barrels of stock-tank oil initially in place in the reservoir. Analyses of the reservoir oilIn that, although the initial reservoir pressure was 1,750 p.s.i., the original reservoir oil was saturated to only 1,300 at which pressure 1 barrel of stock,tank oil contained 525 cubic feet of gas in solution.A serious decline in reservoir pressure during the 2 years of rapid development alarmed the operators and caused them to consider a cooperative pressure-maintenance program. In the latter part of 1939, the K.M.A. Pressure Maintenance Association was organized, and the gasoline plants in the field agreed to process the wet gas and return the dry gas to leases having gas-injection wells. Approximately 27 percent of the cumulative volume of produced gas had been returned to the reservoir by August 1, 1949."

Jun 1, 1952

By James W. Neill

The occurrence of minerals of nickel and cobalt at Mine La Motte is probably known to every mineralogist. I will not attempt to describe these minerals, but, before entering on my subject, will briefly mention the ores, etc., which call for metallurgical treatment and enter into the composition of our mattes. Our staple lead-ore, the dressed galena, is the chief source of nickel and cobalt. It carries but a small percentage of these metals, viz.: 0.2 to 0.3 percent. usually, though when much copper pyrites is contained in the gangue, the amount of nickel and cobalt may be as great as 1.0 to 1.5 per cent. Next in importance is the ((middle product" of the dressingworks, consisting of the sulphides of iron (and copper) with gangue and galena. This usually carries 20 to 23 per cent. of lead, 0.5 to 1.0 per cent. of copper and 2.5 to 3.5 per cent. of nickel and cobalt. A larger percentage of copper always carries with it an increase of nickel and cobalt. In some few cases 12 to 15 per cent. of copper gives 6.5 to 8.0 per cent of these metals. Resides these products of the dressing-works, there is a small quantity of true nickel-cobalt-ore

Jan 1, 1885

By F Gervilla, J Laukkanen

The Kevitsa Ni-Cu-PGE deposit in northern Finland contains disseminated Ni-Cu-Fe sulfides, and platinum-group minerals (PGM). The 2.05 Ga-old ultramafic-mafic, funnel-shaped intrusion is intruded into a volcanosedimentary sequence. The major ore minerals are pentlandite, hexagonal pyrrhotite and troilite, chalcopyrite, cubanite and magnetite. Pyrrhotite and pentlandite are replaced by pyrite, millerite and heazelwoodite near the surface. Nickeline, maucherite and gersdorffite are locally abundant. A pilot feed sample of 575 t of the main orebody at Kevitsa had average grades 0.45 per cent Cu, 0.36 per cent Ni, 1.85 per cent S, 0.33 g/t Pt, 0.34 g/t Pd and 0.19 g/t Au, with 0.06 per cent Ni contained in silicates. Higher PGE contents (2 - 27 ppm) occur in a vertical N-S bearing fault zone. The PGM (n = 6022) mapped in specimens of four drill holes, consist of sperrylite 34.7 vol per cent, braggite and cooperite 18.5 vol per cent, geversite 17.2 vol per cent, moncheite 14.7 vol per cent, merenskyite 6.7 vol per cent, stibiopalladinite 4.3 vol per cent, sobolevskite 1.9 vol per cent, kotulskite 0.7 vol per cent, michenerite 0.6 vol per cent, keithconnite 0.3 vol per cent, rustenburgite 0.1 vol per cent, melonite, froodite, laurite together 0.1 vol per cent and only a few grains of sudburyite, irarsite, vysotskite, erlichmanite, hongishiite, Pt-Cu-alloys, three undefined Pd and Pt bismuthinides and antimonides and a Pd-Cu-bearing Pt-Ni-Fe sulfide. Most of the PGM, 62 per cent, are enclosed in silicates, 29 per cent are intergrown with sulfides, nine per cent are within sulfides. A portion of the PGE occurs in solid solution in sulfides and arsenides. Ni flotation yielded smelter-grade concentrates averaging 12.2 per cent nickel. The average sulfide Ni recovery is 78.8 per cent and total Ni recovery is 65.3 per cent. The average Pt is 10 g/t at 55 per cent recovery, Pd 7.7 g/t at 38 per cent recovery and Au 1.6 g/t at ten per cent recovery. Cu concentrates averaged 28.6 per cent Cu with an average recovery of 78 per cent and further 11 per cent in the nickel concentrate. The copper concentrate contains 4 g/t Au at 24 per cent recovery. The average Fe to MgO ratio 17.9 is well above the targeted minimum of 4.5. The pilot results show that the previously used TETA (triethylene tetramine) can be avoided and good quality, smelter-grade concentrates can be produced from the Kevitsa ore at economical levels of recovery by conventional flotation methods.

Jan 1, 2008

By Afonso Rangel Garcez de Azevedo

A produção de papel gera grande quantidade de resíduo em diferentes etapas da produção, constituído basicamente de celulose e caulim, que atualmente não tem um destino adequado e acaba gerando custos para indústria. O objetivo deste trabalho é avaliar o efeito de ciclos de molhagem e secagem na substituição deste resíduo em massa de cal (5, 10 e 15%) em argamassas a base de cimento e cal, traço 1:1:6 (cimento: cal: areia), para assentamento de blocos e revestimento de paredes e tetos onde serão analisadas propriedades como a perda de massa e resistência mecânica após a ocorrência de ciclos de imersão em água a temperatura ambiente e secagem em estufa em períodos de 15, 30 e 45 dias após o tempo de cura (28 dias). Os resultados encontrados mostraram que a perda de massa apresentada não é significativa, sendo maior em 15%, provavelmente devido à tendência de preenchimento dos poros na matriz cimentícia, quando correlacionados com resultados da argamassa no estado fresco. Quanto à resistência mecânica a compressão, as argamassas não apresentaram perdas significativas que impedisse seu uso em todos os ciclos analisados. Pode-se concluir que os traços estudados apresentam desempenho satisfatório em ensaios de ciclagem podendo com uso recomendado.

Oct 30, 2017