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By A. G. McGregor

DURING the past 5 years, five new copper-smelting plants have been built and put into operation in the State of Arizona. The monthly copper output from these plants averages from 5,000,000 to 18,000,000 lb. Previously, there never was as much activity in copper-smelting plant construction in the same length of time in all the rest of the world. Naturally, in this amount of work, some new problems were met and new features in plant design and. equipment developed. Some of these features are described in this paper. CONCENTRATE HAULING, UNLOADING AND SAMPLING SYSTEM (a) Concentrate Car The International Smelting Co. has provided at its plant at Miami specially designed cars for hauling the concentrates from the mills of the Inspiration Copper Co. and the Miami Copper Co.. The car has a bottom that is readily made tight to hold flotation concentrates and is quickly and cheaply unloaded. Figs. 1, 2 and 3 show views and details of the car. The main feature of this car is the slot in the bottom throughout its length, which is closed by means of short planks that overlap like ship-lap as shown by Fig. 1. At one end of the car an iron gate operated by a screw and hand wheel is provided, which clamps or presses the planks together, making the bottom tight. A removable tapered plug rests vertically over this gate when the loading of the concentrates at the mill commences.

Jan 8, 1916

By A. Soundraraj, S. Singh, R. C. Deshpande

THE detonation of a high-explosive charge having a metal-lined conical cavity (shaped charge) results in a fast-moving jet and a slow-moving slug.1-4 Clark and Bruckner reported the metallographic studies of a cast-iron slug. The present note describes the metallographic studies of a copper slug and discusses the principle of flow involved. The shaped charge consisted of a 5-cm diam cylinder of cast high explosive (60-40 RDX-TNT mixture) having a 45 deg and 0.16-cm thick copper cone. The copper (99.5 pct purity) had a grain size of 0.06 to 0.08 mm diam and a hardness of 65 to 75 Hv. These were fired into a deep container of water and the slugs were recovered undamaged. The longitudinal and transverse sections of the slug were polished, etched, and examined for mi-crostructural changes. Macroexamination revealed a radial grain flow inwards towards the center and a downward component of flow towards the base of the slug. Fig. 1 shows schematically the micro-structural changes observed on the longitudinal section of the slug. The region D near the apex and also along the outer surface of the slug was characterized by the presence of heavily deformed and twinned grains. Some of the grains were having bent or crossed twins, Fig. 2. The grain size in this region was of the same order as that of the

Jan 1, 1960

By F. F. Lines

IT is not the intention of the writer to enter into a discussion of the relative merits of the duplex process as compared with the straight scrap and pig iron process, working under the same conditions, but rather to present in a general way several modifications of the former process, and then describe the method adopted by the Maryland Steel Co., as best suited to local conditions, and also to meet the metallurgical problem presented in the removal from the iron of an unusual constituent-chromium. The principal factors to be considered in deciding whether or not duplexing should be employed are: (1) Chemical constituents of pig iron. (2) Variety and quantity of steel to be produced. (3) Relative cost of pig iron and scrap. (4) Regularity of operation. (5) Capital to be invested. (6) An existing Bessemer plant. Having decided to adopt the duplex process, several combinations may be used, viz.: (1) Acid-lined converter with basic open hearth. (2) Acid-lined converter with electric furnace. (3) Basic-lined converter with basic open hearth. (4) Basic-lined converter with electric furnace. (5) Basic open hearth with electric furnace. The combination of an acid-lined converter with a basic open-hearth furnace is the one most commonly employed, and as it is the one best adapted to the conditions encountered at the plant of the Maryland Steel Co., we will briefly outline the advantages and disadvantages of the different methods of working.

Jan 4, 1915

By C. G. Dunn, J. L. Walter

COULOMB' and Coulomb and Lacombe2,3 have recently discussed secondary recrystallization in soft iron (99.5 pct Fe). They found that the appearance of this phenomenon was dependent on both the presence of impurities and the thickness of sheet specimens. They concluded that impurities such as carbon, sulfur, and oxygen in the soft iron stabilized the matrix structure and allowed growth of a few grains of specific orientations. They also found that secondary recrystallization ceased when the final thickness was small and attributed this complete inhibition of growth in thin sheet to the restraining action of thermal grooves. When purer iron (99.99 pct Fe) was used, normal grain growth but not secondary recrystallization was obtained. On the other hand it is known that the necessary stabilization of the matrix structure for secondary recrystallization in high-purity silicon iron probably does not depend on impurities but more likely results from the specimen thickness effect of Beck et al.,4 according to evidence and ideas advanced by Walter and Dunn,5,6 and Detert.7 Furthermore, Mullins8 has indicated that if a gas-metal surface energy difference exists across a grain boundary equal to or greater than about 3 pct of the grain boundary energy, then such a grain boundary should not become stuck. Similarly, Walter and Dunn have estimated that any increase in restraining force due to increased thermal grooving with decrease in

Jan 1, 1962

By K. A. Kiselev, V. I. Zelentsov, V. P. Nebera

INTRODUCTION Most works on flotation of ions and precipitates from solutions have been summarized recently (1-3). Flotation is more desirable than thickening or centrifuging because of higher recovery, productivity, simplicity of apparatus and better economics in general. Electrolytic flotation that utilizes gases is more favorable than other flotation processes because of the following: higher dispersity of gas bubbles, low coalescence of the bubbles, possibility of gradual regulation of the dispersity and other parameters of flotation (4-5). Flotation from solutions is mostly based on the use of alkaline reagents as precipitants (5). Flotation from acid solutions is less common. We used multicomponent solutions with more than 2-3 components, unlike previous research methods. Acidic flotation allows recirculation of solutions to previous operations such as leaching, etc. REAGENTS FOR PRECIPITATION Electroflotation was studied over a wide range of pH with the addition of ferrocyanide, oxyquinoline, hydroxide and carbonate precipitants. In recent works (1,2,6,7) on flotation of Ni, Cu, Zn from alkaline solutions, mostly ferrocyanides were applied. Our choice was oxyquinoline because of the following: 8-oxyquinoline is a nonspecific reagent for many metals, it is readily soluble in acids and alkalis, oxyquinolates of the studied metals are in soluble compounds, the reagent works over a wide range of pH, it is widely available, oxyquinolate precipitates are stable when exposed to air, are readily floatable, and are easily converted to oxides of the metals by sintering.

Jan 1, 1980

By Fred Chappell

Pyrophyllite, a hydrous aluminum silicate, physically similar to talc, receives its name from the Greek word Pyr, for fire and phyllite, a rock or stone. Firestone refers to its first recorded use as firestones or hearthstones. Composition and Properties Pyrophyllite is an aluminum silicate A12O34SiO2H2O (alumina 28.3 pct, silica 66.7 [ ] pct, water 5.0 pct) (Table 1). Vanderbilt1 gives pH value of pyrophyllite as 5.6 to 8.4. Pyrophyllite is usually white or cream, though it may be found in shades of pale green, pale yellow, buff or light gray, and in darker shades and other colors principally due to oxidation of contained iron minerals. It is opaque to translucent in thin sections. Its hardness is 1 to 2 in the Mohs scale. Its specific gravity is 2.8 to 2.9. Its luster is pearly to dull; it is recognized chiefly by its micaceous structure and cleavage, and its soft greasy feel. Two other varieties occur, one in which there are radiated needles in the crystalline form, and there is also a massive homogeneous structure found. Fine grinding reduces pyrophyllite to fiat plates or scales but aggregates of minute foliated plates may be formed.1 Distribution of Deposits Pyrophyllite is found in metamorphic rocks throughout the world but it is only in comparatively recent years that it has assumed much commercial importance. The principal

Jan 1, 1960

By Paul Berggreen

LIST OF PUBLICATIONS In the Bibliography titles of publications are replaced by corresponding symbols in this list. American A-1. Transactions of the American Institute of Mining Engineers, New York. A-2. Journal of the New York Microscopical Society, New York. A-3. Journal of the Franklin Institute, Philadelphia, Pa. A-4. The Metallographist, Boston, Mass. A-5. The Electrochemical and Metallurgical Industry, New York. A-6. Bulletin of the American Institute of Mining Engineers, New York. A-7. The Iron Trade Review, Cleveland, Ohio. A-8. The Journal of Physical Chemistry, Ithaca, N. Y. A-9. The Physical Review, New York. A-10. Van Nostrand's Electric Engineering Magazine, New York. English E-1. Proceedings of the Institution of Mechanical Engineers, London. E-2. Journal of the Iron and Steel Institute, London. E3. Proceedings of the Institution of Civil Engineers, London. E-4. Journal of the Chemical Society of London, London. E-5. Philosophical Magazine, London. E-6. Proceedings of the Royal Society of Edinburgh, Edinburgh., E7. Carnegie Scholarship Memoirs, London. E-8. Proceedings of the Royal Society of London, London. E-9. Chemical News, London. E-10. Philosophical Transactions of the Royal Society of London,, London. E-11. Transactions of the North-East Coast Institution of Engineers and Shipbuilders, Newcastle-on-Tyne E-12. Iron, London. E-13. Nature, London. E14. English Mechanic and World of Science, London.

Jan 6, 1914

Roof Bolts An expansion shell and plug Westinghouse roof bolting assembly made for use with threaded steel rods and large flat washers or steel channel employs a plug larger in diameter than those for trolley wire service. The notched plug helps prevent shell and plug from turning. The unit is shipped complete. Circle No. 1 Fan The Jeffrey Mfg. Co. Aerodyne Midget fan is a self contained blower or exhauster for auxiliary ventilation through tubing. Operating rating with 5 hp motor is 6.5 in. maximum static pressure, and 6200 cfm free delivery volume. Weight is 340 to 475 lb and it may be furnished in open or permissible form. Circle No. 2 Heavy-Density Initial installation in the Mesabi Range country of the Wilmot-Daniels heavy-density concentrating system was a 175 ton per hour plant at the [ ] Skubic Bros. Virginia, Minn., operation. This Wilmot Engineering Co. unit has a separatory vessel providing unidirectional medium flow and as the only moving part uses a standard drag-line conveyor for lifting sink out of the bath. Circle No. 3 Portable pH Meter A low priced battery-operated portable pH meter of utmost simplicity announced by the Photovolt Corp. uses only 3 ordinary radio batteries which give over 2000 hours of service. Accuracy of 0.03 pH is claimed by the manufacturer for the model 125, and AC power line supply is available. Circle No. 4

Jan 1, 1952

By G. W. Elger, H. E. Bell, J. E. Tress, J. B. Wright

This paper describes laboratory techniques and subsequent results of US Bureau of Mines (USBM) research to produce chlorination-grade feed- stock from an abundant, low-grade, domestic, rock ilmenite ore. The research is part of the Bureau effort to devise technology that may help decrease US dependence on imported raw materials. A rock ilmenite containing about 46 wt % TiO2 was smelted in an electric arc furnace with coke, wood-chips, and Na2CO3 to separate most of the iron as pig iron and to form a low-iron, titanium-enriched slug. The slug was ground, pelletized, oxidized, and then sulfated with mixtures of SO2 and air in a continuous 4.5- to 9.1-kg/h (10- to 20-lb per hour) apparatus at 1023° to 122J0 K (1380° to 1740° F). The sulfated slug, containing 60% to 65% TiOb, was reground and leached in water at ambient temperature to decrease the combined levels of the troublesome calcium, magnesium, and manganese impurities from 7.0 to 1.7 wt 70. The final product was upgraded to about 8.4 wt % TiO2. This material is potentially suitable for chlorination in a fluidized bed reactor. The most favorable results were achieved with leached slug sulfated at a feed rate of 4.5 kg/h (10 lb per hour) and at temperatures of 1073° to 1123° K (1470° to 1560' F).

Jan 1, 1986

By W. A. Krivsky, R. Schuhmann

PREVIOUS papers in this series on the thermo-•t dynamics of copper-smelting systems have presented a survey of the field and an outline of the overall program: thermodynamic studies of iron silicate slags, 2-4 and thermodynamic data for simple mattes in the Cu-S system.5 Since this program was started, an excellent summary of the whole field of physical chemistry of copper smelting was published by Ruddle. The present paper represents a further step in the study of liquid mattes, and deals specifically with the Cu-Fe-S system. The importance of the Cu-Fe-S system to copper smelting is evident from the fact that these three elements constitute 90 to 99 pct of the totalweight of most commercial mattes. In copper mattes oxygen is an important fourth component. Oxygen was rigorously excluded in the work to be described in this paper. However, the behavior of oxygen in mattes was the subject of a companion research by Lander' which will be described in a subsequent publication. Several studies have been made previously of phase equilibria in the Cu-Fe-S system,8-10 so that the ternary phase diagram is fairly well established in most regions. Also, separate studies have been made of the phase diagrams and thermodynamic properties for the three binary systems: CU-S,5,12-15 CU-Fe,11,14,17 and FeS.11,14,16,17 However, no work has

Jan 1, 1958

By I. R. M. Chaston

Radial layout’s guiding principle is the grouping under one roof of the operating processes which require continuous supervision. Separate treatment sections are isolated by outside stockpiles fed with radiating conveyors. Hence the name ‘radial’ layout. Many plants are designed with ‘linear’ layout where successive operating stages are dotted like beads along a string of conveyors. [Figures 1 through 5] show the development of the radial concept in the layout of heavy-media diamond recovery plants over

Jan 1, 1979

Organization Place Date 1919 Automotive Engineers New York, N. Y. Feb. 4-6 American Institute of Mining Engineers New York, N. Y. Feb. 17-20 New England Association of Gas Engineers Boston, Mass. Feb. 19 American Institute of Electrical Engineers New York, N. Y. Feb. 19-21 National Society for the Study of Education Chicago, Ill. Feb. 25-28 American Railway Engineering Association Chicago, Ill. Mch. 18-20 American Electrochemical Society New York, N. Y. Apr. 3-5.

Jan 2, 1919

THE iron and steel industry spent $1,170,000,000 in 1952 for improvements and expansion, with an accompanying rise of 9 million net tons in capacity to 117.5 million tons of ingots and steel for castings. More than $4,600,000,000 has been invested in the seven years following World War 11. An average of $1260 has been laid out every minute during those seven years for an increase in capacity of 25.6 million tons.

Jan 3, 1953

By M. Deighton, R. N. Parkins

The metals Cd, ,Wg-, Sn, TI, Zn, and Zr reach a peak hardness after a criticfir1 deformation by rolling- and then soften with fwther rolling-, thereby exhibiting wovk softening. Optical metallography on Cd, Mg, and Zn shows that work softening is accompanied by a change in grain size occurring during deformation. The creep of zinc from -1l° to +60°C at stresses in the range of 7.9 to 17.3 kg per sq mm is given by € = e0 -t- Bt + Kt +at6. The third and second rate constcints are related by the equation a = K~ K6 and their stress and temperature dependence can be represented by the equations K = A, . exp - (u, - Bu)/kT. A model based upon the stress activated glide of sub-boundaries is proposed which qualitatively accounts for the metallog-raphic observations. Expressions, which are in reasonable quantitative agreement with the ex-pe~inzental observations, are derived for the creep of zinc. THE term "work softening" has been used previously by Polakowski1 and by Cottrell and stokes2 to describe phenomena where further strain of a deformed material leads to a decrease in flow stress. In both cases, however, the conditions were changed for the second straining. Here, the term "work softening" is intended to refer to a decrease in flow stress after continued straining in the same direction at the same temperature: work softening is the antithesis of "work hardening". Work softening of zinc was reported by chadwick3 and in discussion of that paper Jenkins4 indicated that cadmium also work softens. More recently work softening has been reported5 in two magnesium alloys, -99.5 pct Mg. Chadwick found that the hardness, 0.2 pct Proof Stress and the UTS of electrolytic zinc all increased with progressive cold reductions up to 30 pct and then progressively decreased with further rolling. Gay and Kelly6 used a back-reflection X-ray technique to study the effect of cold rolling zinc and found that although deformations greater than 2 to 5 pct reduction in thickness produced some recrystallized grains, deformations greater than 40 pct caused com-plete spontaneous recrystallization. At deformations greater than 60 pct the material was found to consist solely of recrystallized grains, -20 pm diam, the size of which decreased with increasing reduction and was much less than the initial grain size of the annealed material (-300 pm diam). Similar results were also reported for cadmium, tin, and lead.6 Gay, Hirsch, and Kelly' suggest that these experiments indicate recrys-tallization takes place when the dislocation density exceeds a certain value. However, no measurements of MATERIALS AND EXPERIMENTAL PROCEDURE The purity of the metals used in this work is indicated by the following figures: Zn (99.99); Cd (99.94); Mg (99.95); T1 (99.99). The zirconium was iodide crys tal bar with a probable purity of about 98 pct. The metals were obtained in the form of 0.25 in. thick strip or 0.425 in. diam rod by various fabrication methods and then annealed to ensure complete re-crystallization. Hardness-deformation curves were obtained at room temperature by rolling 4 in. thick strip under conditions which left a surface adequate for diamond pyramid hardness tests immediately after rolling. The hardness was taken as the niean of five impressions made using a 5 kg load and the time elapsing between rolling and making the last impression never exceeded 5 min. The zinc specimens for creep testing were from 3 by 3 by 4 in. cast slabs which were rolled to 0.10 in. thickness starting at 350°C and finishing cold. The resulting strip was cut into pieces 1 in. wide and annealed in batches. With suitable choices of annealing temperature between 100" arid 400°C five different grain sizes varying from 4.54 x 10' to 3.03 x l05 grains per sq cm (530 to 20 um diam) were obtained. Creep tests were done in compression using a sub-press, based on a design after Ford,8 in which the strip is compressed between dies 0.100 in. wide under conditions of plane strain. Since there is no lateral spread of the material, the area of contact between the dies and strip remains constant throughout the test and the application of a constant load, using the load maintaining device of a hydraulic testing machine, resulted in a constant stress. Covering the dies with strips of P.T.F.E. reduced frictional effects to a minimum. The creep strain was obtained by measuring the travel of the crosshead of the testing machine to a sensitivity of 0.1 pct reduction in thickness. The complete subpress assembly was contained in a steel box and for tests above the ambient this was filled with liquid paraffin and heated electrically. Temperatures below the ambient were obtained with a cooling mixture of acetone and solid carbon dioxide in the box. The liquids were stirred and the temperature of the specimen, which was controlled to ±0.5"C dur-ing a test, was measured by a thermocouple placed near the dies. Compression testing of cylindrical specimens was also carried out in the subpress using hardened flat discs separated from the test material by P.T.F.E. sheets which obviated barrelling of the specimens. Various initial strain rates were supplied by the hydraulic testing machine, and the deformation was measured by a clock dial gage resting on the cross-

Jan 1, 1970

By John S. Crandall

Occurrence: small crystals in alluvial sands from the eroding Belt Series mica schists. Flowsheet: dragline, trommel screen, jigs, drier, crusher, screens. Value: ground, $2.50 per cu yd, garnet sand gross $60. per ton. Costs: production and sales $48. per ton. Uses: blasting sand in aircraft plants, monumental works, foundries. Efficiency comparison: superior to silica sand. Future: possibilities only touched upon, research continuing.

Jan 1, 1950

The mining companies on the page opposite are among the elite industrial 500 in Fortune magazine's June Directory of U. S. firms that rang up the largest dollar sales volume in 1967. The companies are listed according to their 1967 sales rank, which is given along with their 1966 rank for comparison. Mergers played an important role in the addition and deletion of several companies to the list. Tenneco, Occidental Petroleum and Gulf & Western Industries made the list of mining companies by their purchases of Kern County Land, Island Creek Coal, and New Jersey Zinc, respectively. In turn, these three companies disappeared from the list. General Aniline & Film acquired Ruberoid, and Ideal Cement is now a part of Ideal Basic Industries -a name change only. Only two companies, St. Joseph Lead and U.S. Smelting, Refining & Mining, were actually displaced from the list. The mining industry increased its sales 14.5%, placing fourth among the 22 industrial classifications listed in the Directory. However, among the ten biggest losers in sales were four mining companies-Kennecott Copper, -33.8% ; Asarco, -21.8% ; Amax, -16.5%; and Anaconda, -15.1%.-which was mostly a result of the copper strike, except for Amax which suffered strikes at its molybdenum and aluminum operations. Mining heads the list of industries for return on sales and assets per employee, while it rests at the bottom with respect to sales per dollar of invested capital.

Jan 8, 1968

H. 0. HOFMAN, Boston, Mass (written discussion*).-The paper by Mr.. Pyne gives clear evidence of the difficulties the metallurgist is likely to encounter when he tries to recover in the blast furnace the metal from old chromite lining used as a refractory material in the copper reverberatory furnace. It appears that chromite cannot be fluxed at temperatures which usually prevail in copper blast furnaces. This calls to mind the freezing-point curve drawn by M. Simonis1 of mixtures of chromite and kaolinite. The chromite used in the experiments contained 52.9 per cent. Cr203, 22.6 FeO, 4.8 AI203, 9.6 Si02, .10.1-MgO; FIG. 1. the kaolinite was clay from Zettlitz with 98.5 per cent. clay-substance: The accompanying curve shows that the eutectic mixture with 35 per cent. kaolinite and 65 per cent. chromite freezes at Seger cone No. 15 (1435° C.), while kaolinite fuses at cone No. 35 (1770° C.) and chromite at cone No. 42 (2000° C.). The curve indicates that the difficulty in the blast furnace can be overcome by having at the smelting zone a temperature much higher than is usual in copper smelting; a charge composition similar to that prevailing at the Mansfeld copper smeltery -which gives with 23 per cent. coke a, slag of the composition Si02, .49.09; .(FeMg)0, 5.58; (CaMg)0, 16.02; A1203,-16.02-might flux and fuse chromite.

Jan 3, 1918

By M. H. Gidel, D. C. Bard

These notes are based on the megascopic study of a suite of 2,400 specimens of minerals and ores from the Butte mines, combined with field observations at intervals over a period of several years. The estimate of average vein composition is based on field acquaintance with the veins. It is probably correct in its broader proportions, and should be of use for comparison. Chemical and Mineral Composition of Unoxidized Vein Matter. Per Cent. Oxygen,......48.00—Quartz, rhodonite, rhodochrosite, sericite, kaolinite, barite, calcite, and hübnerite. Silicon,...... 36.O0—Quartz, rhodonite, sericite, kaolinite, and willemite (very rare). Sulphur,.....5.0—Sulphides of iron, zinc, copper, lead, and sulphates of barium and rarely calcium. Iron,.......5.00—Ferric sulphides (pyrite, bornite, chalcopyrite), also in sphalerite, tetrahedrite, and rarely hematite and siderite. Manganese,.... 2.00—Rhodonite, rhodochrosite, and hübnerite. Zinc,.......1.00—Sphalerite, very rare wurtzite and willemite, and tetrahedrite and tennantite. Carbon,......0.50—Rhodochrosite and calcite. Capper,......0.75—Cuprous ( + ) and cupric (—) sulphides. Aluminum,.... 0.50—Sericite and kaolinite. Hydrogen,.... 0.50—Water, sericite, and kaolinite. Potassium,.....0.20—hicite. Lead,....... 0.20—Galena. Arsenic,......0.10—Tennantite and enargite. Barium,......0.10—Barite. Calcium,.....0.10—Fluorite, calcite, and rare gypsum. Antimony,.... 0.02—Tetrahedrite, famatinite, and silver sulphantimonites. Fluorine,.....0.05—Fluorite. Silver,.....1 —Argentite, and sulphantimonites. Tungsten,.... —Hübnerite. Phosphorus, • —Wavellite. Bismuth,' .... 0.05—Sulphide (?) Tellurium,... 1 —Telluride (?) Selenium,.... —Selenide (?) Cadmium,.... —Sulphide (?) Gold,..... —Native and telluride (?)

Jan 1, 1914

Geological and Natural History Survey of Minnesota, Minneapolis, Minn W. H Emmons, Director A list of publications will be sent upon application Orders for publications should be addressed to The University of Minnesota Press, Minneapolis, Minnesota The Geological Survey of Minnesota has a record of long and useful service Some of the papers published have been outstanding in their field A series of 24 Annual Reports, covering the years 1872 to 1895-98, inclusive, was issued, of which 16 are still available at a price. More important however, are the six volumes of Final Reports, in which is collected the material presented in the earlier Annual Reports. All the strictly geological papers are found in four of the volumes of the Final Reports. vol 1 (1872-1882), principally geology by counties, 2 (1882-1885), same as 1, 4 (1896-1898), same as 1, 5 (1898-1900), Structural and petrographic geology Prices for each volume, leather $3, cloth $2 50, excluding postage, unless other directions accompany the order, volumes of the Final Reports will be sent express collect. A series of Bulletins has been issued, of which a few are out of print. Considering only those available, and of greatest interest, they are: Bulletin 5, Natural gas in Minnesota, by N H Winchell (1889), 50 cents, 6, Iron ores in Minnesota, their geology, discovery, development, qualities and origin, by N H Winchell and H V.

Jan 1, 1933

By Emile Hiertz

THE first press was installed in June, 1910, and the second in March,1911. They produce 1,000 briquettes per hour, weighing 5 kg. (11.05 1b.) each, under a pressure of about 400 kg. per square centimeter (5,689.2 lb. per square inch). The chloride of magnesium is received from the potash mines at Hanover in tank cars in approximately a 35 per cent. solution. The quantity of solution added to the flue dust varies between 2 and 3 per cent., so that the briquettes contain about 1 per cent of MgCl2. To fresh dust as much as 10 per cent. of coke breeze may be added and bri¬quettes made that still have a crushing strength of from 25 to 30 kg. (377 to 426.6 lb. per square inch) after 36 hr., and 45 kg. (639.9 lb. per square inch) after six days. After having treated 140,000 tons of the material, the reports of the blast furnaces show that the briquettes improved the action of a furnace and produced less dust than did Minette ore. As much as 35 per cent. of briquettes is added to the furnace charge without bad effects on operations. The presence of chlorine did not produce any corrosion in the furnace, downtakes or other piping. The presence of a certain amount of chlorine in the dust reduces the amount of chloride of magnesium which it is necessary to add for briquetting.

Jan 12, 1913