Synopsis of Recent Chemical and Metallurgical Literature

Copper in Slags-A very important contribution. to our knowledge as to the exact condition in which copper is held in furnace slags appeared in Engineering and Mining Journal for May 10, 1919, Volume 107, page 815, from the pens of C. G. MAIER and G. D. VAN ARSDALE. Their investigations were confined exclusively to Phelps-Dodge slag when making a 30 to 40 per cent matte by smelting raw or roasted sulphides. Microscopically, such matte shows FeS islands in Cu,S, ground mass, as in the globule of Fig. 6. Silver-nitrate is a good etching agent, deeply corroding the Cu,S, which fact is utilized in determining whether any copper sulphide is present as a true solution in the slag. showed no effect on

FIG. 6. BLAST-FURNACE SAG, CHILLED UNETCHED INCLUSION

IS UNALTERED MATTE.

X 35

Under a microscope this reagent

slag, while it actually dissolved more than 98 per cent of the copper from mattes and white metal. The equation is probably

Cu,S+4AgNO, = 2Cu (NO,), + 2Ag + Ag,S Analyses of several blast-furnace and reverberatory slags showed an average residue of 0.7 per cent copper insoluble in AgNO,, with an average deviation of only 0.11, which figure (0.7 per cent) possibly represents the maximum solubility of some copper compound in such slags as 36 per cent SiO,, 10 per cent Al,O,, 34 to 42 per cent FeO, 4 to 18 per cent CaO + MgO.

Table I shows various possible forms whereby copper may be held in slags.

Since no oxidized copper minerals were found in crystallized samples, and also since the copper dissolved in slags appeared to be a constant quantity, it is prob

FIG. 2. CONVERTER SLAG, UNETCHED. FLOTATIVE EFFECT OF BUBBLES INDICATED BY CO-PLANAR OCCURRENCE. X 150

Coagulation and Settling

FIG. 34.

FIG. 7. CHILLED BLAST-FURNACE SLAG; INCLUSION WITH LITTLE FeS. X 35. FIG. 10. CHILLED BLAST-FURNACE SLAG; FeS CONSTITUENT ELIMINATED; WELL DEVELOPED GAS BUBBLES. X 150

actual nature of this soluble sulphide is not known, but it very likely contains little FeS, because the latter ordinarily tends to disappear in the microscopic globules observed-in other words the shot of typical matte shown in Fig. 6 is usually replaced by spherical inclusions such as Fig. 7 or 10, where the FeS has largely disappeared, thus leaving particles of Cu,S containing more or less FeS in solution. Iron sulphide constituent is not commonly observed even in slags from high grade matte. Gas bubbles appear to be attached to the inclusions

2

curs only at a narrow range of temperatures giving a mushy state. From microscopic evidence, the authors conclude that, since gas bubbles accompany the disappearance of FeS, the gas is probably SO,. It is logical to assume that Fe,O, is the oxidizing agent since ferrous oxide and dissolved air would produce metallic iron and copper, respectively, neither of which was found. Ferric oxide is present, since it is required to form the magnetite ordinarily present in furnace slag. Magnetite occurs in converter slags in allotriomorphic crystals shown in Fig. 36. Magnetite is also present in reverberatory slags in holomorphic crystals often with fringes of dark colored Fe,O, (Fig. 34), or in dendritic form (Fig. 27). However, magnetite was not found by these authors in their blast-furnace slags, whose structure is represented by Fig. 35.

Apparently, therefore, copper is held in furnace slags to a certain small extent as a true solution of sulphide, while the balance occurs as globules of white metal floated by attached gas bubbles. Continued settling would not appear to reduce the quantity of the latter, which could only be done by changing the composition of the slag so as to practically eliminate the occurrence of ferric oxide. Converter slags may contain as high as 0.5 per cent of copper in true solution, with the balance present as particles of white metal. As the blow continues the soluble copper continually decreases. Here is additional evidence that practically no copper silicates are formed in normal furnace practice.

Recent Chemical and Metallurgical Patents

Automatic Hardener.-T. J. FAY of Brooklyn, N. Y., has patented a special machine, illustrated here. with, designed for the automatic cambering and heat treatment of such parts as spring leaves. A heated plate of spring steel containing about 1 per cent carbon is heated to about 1535 deg. F., and placed on the lower anvil 7. The recessed upper head 11 then descends, shaping the bar to the desired radius. The entire assembly then descends past the oil sprays 40 and 41 into the tank below, which contain an oil layer 12 in. thick, resting upon a body of water. The passage of the oil layer requires 3 sec. when the hot metal is held in the water for 57 seconds. After this time the mechanism is elevated out of the fluid, and

the cool, cambered bar removed from the machine. The temperature of the metal and the relative time it is held in oil and water are subject to variation depending upon the kind of metal being treated. The entire equipment is electrically driven and by means of time relays the proper intervals can be absolutely fixed and repeated, so that at the end of the operation the core of the leaf will contain enough residual heat so that it may be properly annealed by blooming. (1,298,682; assigned to Standard Parts Co., Apr. 1, 1919.)

Ignition of D. & L. Cake.-C. W. ADAMS of Murray, Utah, notes that many times the usual oil-flame ignition for a Dwight & Lloyd sinter cake is not entirely satisfactory. In some cases such intense ignition fuses a crust on the top of the ore, making the charge semi-impervious to the passage of oxygen. This causes elemental sulphur to distill into the flues,

giving rise to the danger of explosive combustion. High loss in lead and silver is also characteristic of such practice. The inventor proposes to ignite the cake by spreading a thin layer of hot calcine on it. One-half inch of a bright red calcine having 12 to 15 per cent sulphur content has been satisfactorily used and has been found to obviate the disadvantages attending high-temperature ignition. For ease it is suggested that the hot calcine be discharged from a roasting furnace placed directly above the sintering machine. (1,299,892; assigned to American Smelting & Refining Co., Apr. 8, 1919.)

Resistors for Electric Furnace.- H. G. WEIDENTHAL of Cleveland, Ohio, suggests a novel arrangement for an electric furnace, whereby gangs of parallel, vertical resistors form the inner lining of the furnace laboratory. These terminate below in a conductor placed below a refractory hearth, which is banked up somewhat above their lower ends, and above are clamped to a conducting bar, in such a way that any damaged individual may be easily removed. Resistor gangs are so arranged as to allow spaces for pouring spout, and charging and inspection doors. For the individual resistors the inventor suggests molded rods of carborundum sand, coated with crystalline corborundum. At least one of each gang must have a small conducting rod in its axis, so as to start the current through the carborundum, which has a high resistance when cold. (1,304,425, assigned to J. H. Herron Co.; May 20, 1919).

Converter Puncher.-CHARLES J. ARCH of Douglas, Ariz., has patented an automatic device for punching tuyeres in a copper converter. It consists of a frame carrying several air cylinders, one lined up for each tuyere, and with valves interlinked in a train so that each tuyere shall be punched by the piston rods in succession upon starting the first. Any plugged tuyere can also be skipped. Removable piston-rod ends are provided against wear, and a circular scraper is placed some distance ahead of the cylinder so that adhering slag may be peeled off the rod. The entire apparatus is counterweighted and normally connected by side arms to the connector shell and it tilts in a circle as the converter moves. Automatic releases are provided, however, so that the puncher is left stationary when the converter passes a limiting position. (1,303,755, May 13, 1919.)

Electrolytic Tungsten.-Present methods of drawing hot tungsten wire through diamond dies lubricated with graphite form an undesirable carbide alloy. F. G. KEYES of Cambridge, Mass., finds that WO, will dissolve in boric acid at 1200 to 1400 deg. C., and may then be electrodeposited upon, say, a fine tungsten wire. When the deposit has grown to sufficient size. it will be found somewhat ductile and can be drawn through dies of high-speed steel lubricated with tale (1,293,117; assigned to Cooper Hewitt Electric Co., Feb. 4, 1919.)

Crucibles.-F. J. TONE of Niagara Falls. has discovered that a very excellent crucible for melting metals can be made of 40 per cent graphite ground to 16 mesh, 40 per cent commercial magnesia, sintered in the electric furnace and ground to 40 mesh, and 20 per cent plastic refractory clay. This forms a plastic mass which can be made into crucibles and fired in the ordinary manner, and produces a superior, tough article which resists scaling or slabbing under heat variation in a superior manner. (1,303,993; May 20, 1919.)

Detinning Process.-WALTER ZACHARIAS of Pittsburgh, Pa., has discovered that when dry tin scrap is treated with chlorine, the reaction forming SnCl, starts at local points when the concentration reaches a rather high figure, but rapidly spreads to all parts of the mass by the liberated heat. In order to prevent unduly high temperatures (which form undesirable iron chlorides) and loss in excess chlorine, he proposes to start the reaction when only low concentrations of chlorine are present by the addition of finely powdered metallic tin, which by virtue of its high specific surface will react at low temperatures and concentrations. He also proposes to place a hopper containing powdered tin above a suitable opening in the detinning vessel, so that this reagent can be introduced at will to regulate the temperature within, and to avoid the loss in time, chlorine, iron and tin chloride certain to follow undue irregularities. (1,283,016; Oct. 29, 1918.)

Improvements to Electric Furnaces.-W. E. MOORE of Pittsburgh, Pa., patents features designed to improve mechanical operation of electric furnaces. For instance, he recommends an arched bottom plate so that local heating may not destroy the furnace lining by buckling. A tilting arrangement consisting of stationary traction rollers, gear driven, is also suggested. Electrode holders should also be mounted at the side of the

FIG. 1. ELECTRODE HOLDER

furnace and capable of rotation about the axis of their supporting column, so that they may be swung away from the furnace roof when renewing roof or electrode. This arrangement also allows the hoisting chains to be drawn together to a point near the tilting center of the furnace, and thence leading them off to any convenient location for the motors. Electrode holders and arms themselves should preferably be split and hinged some

the other side of the skip-bridge (4). This construction is proposed in order that a considerable proportion of the dust taken off by furnace gases or explosions may be arrested and fall back into the furnace proper before passing into the downtake. (1,303,914; May 20, 1919.)

Preparation of Iron Ore.-W. G. SWART of Duluth, Minn., and B. G. KLUGH of Anniston, Ala., note that certain fine or clay-bearing iron ores or concentrates, or high-sulphur ores, must be agglomerated before use in blast-furnaces. Commercially such agglomeration is best performed on an intimate mixture of fine ore and solid fuel, with sufficient water to make it plastic. Mixing of such wet, sticky masses is extremely difficult and expensive, and the inventors propose to take unwatered concentrates (or make up a thin pulp of the iron-bearing material), add dry pulverized coal or even wet peat, agitate thoroughly, and then filter the now well-mixed mass on a continuous filter so operated that the resulting cake shall have the proper proportion of moisture for sintering. (1,303,411, May 13, 1919.)

Lactic Acid. By digesting sawdust with a solution of lactic acid, GEORGE A. RICHTER of Berlin, N. H., obtains a mixture containing reducing sugars. After filtering, the solution is treated with an excess of calcium carbonate and fermented by lactic acid bacteria. The excess CaCO, serves to neutralize the lactic acid as rapidly as it is formed during fermentation. Sufficient sulphuric acid is added to precipitate all the calcium as sulphate, which is filtered off, leaving a solution of lactic acid. (1,305,623; assigned to the Brown Company; June 3, 1919.)

Personal

The Salt Lake office of CHEMICAL & METALLURGICAL ENGINEERING has been closed and transferred to Rialto Building, San Francisco, Cal. Mr. Ernest E. Thum, formerly Western Editor, will be transferred to New York City as associate editor and Mr. L. W. Chapman, formerly with the Anaconda and duPont organizations, will go to San Francisco as Western editor.

DR. RAYMOND F. BACON, Director of the Mellon Institute of Industrial Research, received the honorary degree of Doctor of Science, on the occasion of the annual commencement of De Pauw University, Greencastle, Indiana, on June DR. H. K. BENSON has received his discharge as a captain in the research section of the nitrate division of the Army Ordnance and has returned to the University of Washington, Seattle, to resume his work as professor of chemical engineering and administrative head of the Department of Chemistry.

MR. FRANCIS S. BOSQUI will shortly open his office as metallurgical engineer at 90 West Street, New York City. MAJOR ARTHUR S. Dwight, 11th Engineers, has recently returned to civil life after two years service in France with the A. E. F. On June 26 he addressed the New York Section of the A. I. M. E. on his war experiences.

MR. ELLWOOD HENDRICK, consulting editor of CHEMICAL & METALLURGICAL ENGINEERING, expects to sail for Venezuela, Wednesday, July 2.

COL. G. A. BURRELL has received the Distinguished Service Medal for his work as chief of the research Division, Chemical Warfare Service, during the war.

DR. VANNOY H. MANNING, director of the United States Bureau of Mines, on the occasion of the annual commencement of the University of Pittsburgh on June 13, received the honorary degree of Doctor of Engineering, in recognition of his noteworthy accomplishments in the investigation of problems of mineral technology. The university also conferred the honorary degree of Doctor of Chemistry upon DR. WILLIS R. WHITNEY, director of the Research Laboratory of the General Electric Co., Schenectady, New York, because of the valuable service which he rendered to the Government as a member of the Naval Consulting Board. These honorary degrees were given upon the recommendation of the Mellon Institute of Industrial Research, an integral part of the University of Pittsburgh.

PROFESSORS W. A. PATRICK and M. E. REID of the chemical department of the Johns Hopkins University will act as consulting chemists for the du Pont organization during part of the vacation period.

DR. J. W. RICHARDS, professor of metallurgy in Lehigh University and secretary of the American Electrochemical Society, leaves New York July 3 for Norway. After visiting some electrochemical plants in Norway and Sweden, and his son in Copenhagen, Dr. Richards will return about the middle of September.

MR. E. H. ROBIE, recently assistant metallurgist for the Canadian Copper Co., Copper Cliff, Canada, has joined the editorial staff of Engineering and Mining Journal.

DR. JULIUS STIEGLITZ has been appointed chairman of the advisory committee on synthetic drugs to the Chemical Foundation, Inc., New York.

MESSRS. THORNE L. WHEELER and JOHN C. WOODRUFF have formed a partnership for the general practice of chemical engineering under the firm name of Wheeler & Woodruff, with offices at 280 Madison Ave., New York.

MR. EDWARD S. WIARD has resigned as consulting engineer for the Colorado Central Mines Co. and the Anondaga Mines Co. and will resume regular practice at 409 Boston Bldg., Denver, Colo.

MR. HORACE V. WINCHELL, president of the American Institute of Mining and Metallurgical Engineers, recently addressed the New York Section on the new developments at the Eastern end of the Mesabi Range in Minnesota.

Book Reviews

BOILER CHEMISTRY AND FEED WATER SUPPLIES. By J. H. Paul. 242 pages, illustrated. New York: Longmans, Green and Co.

The author has included a great amount of original data taken from his own experience. The book is written with the point of view of the usual technical training of the average power engineer in mind. Boiler chemistry is mainly concerned with the innumerable reactions that take place when natural waters are heated to around 400 deg. F. under a pressure of fifteen to twenty atmospheres. The chapter on water softening processes is too limited in scope. The book will serve a long neglected field and should be read by all engineers concerned with steam engineering. WALLACE SAVAGE.

Current Market Reports

The Non-Ferrous Metal Market

Tuesday, June 24.-The prospects of the signing of the Peace Terms as well as the summer impetus toward increased construction work have greatly strengthened the metal market. Prices that had declined are now rising.

Aluminum:-No variation from the 33c. per lb. price on 98-99 per cent ingots is reported. Scrap sales are equally stable: Cast, 20-23c.; sheet, 20-23c., and clippings, 224-26c. Sheets, 18 gage and heavier, 42c. Powder, $0.70-1.40 lb.

Antimony:-There is a slight shortage in antimony supplies, wholesale spot bringing 8c. and future 8-81c. lb. Job lots, 8gc. lb.

Copper:-The copper market is showing considerable strength with 18c. lb. for spot and 18 c. for August futures. Predictions of 20c. copper are being made.

The Iron and Steel Market

The key to the steel market's future is the relation between the buying of steel for ordinary everyday consumption and the buying of steel for construction purposes or permanent investment. Such claims as have been made that the outlook is unfavorable have been based on a view that buying of steel for permanent or prolonged use, in other words for investment, is abnormally small, but such an argument defeats its own end, for it that were true the buying that has been in progress has been purely for current consumption, and that buying has lately represented more than 60 per cent. of the productive capacity.