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Grinding Brass Ashes in a Ball Mill

In the manufacture of brass and brass products the weight of the finished product leaving the plant is much less than the total weight of copper and zinc entering. A small part of this discrepancy is due to the unavoidable oxidation of the metals in melting, but by far the largest part of the loss is in the form of metallic particles of copper, zinc, and brass. These losses occur principally at three points in the process:

  1. in the casting-shop ashes;
  2. in the slags from furnaces melting scrap brass;
  3. in material spilled on the floor throughout the manufacturing process.

The amount of these products in some plants is nearly 100 tons per 24 hours.

Casting-shop ashes contain the metal spilled from the crucibles during melting and pouring, and the metal included in the slags formed in the melting process. The ashes also contain pieces of broken crucibles with adhering metal; 20 to 30 per cent, of unburned coal is also present. The metal in casting-shop ashes contains clean pieces of zinc or copper ingots weighing 1 to 2 lb., jagged pieces of metal of all shapes ranging in size from several inches down to the finest dust, and shot and

Diastrophic Theory

The writer has devoted a number of years to practical operations and to the study of geology in the oil fields. In consequence, he has been brought to investigate the theories advanced to account for the accumulation of oil and gas in commercial deposits. It is the result of these investigations and his personal conclusions that he wishes to sum up in this paper.

The writer is an advocate of the organic origin of petroleum found in pools. He has been led to believe that the present theories of oil and gas accumulations are incomplete and, in certain respects, incorrect, although they may embody certain elements of truth; that the forces that are called upon to explain the movement are only secondary forces in the process, and insufficient, by themselves, to cause this movement; and that the phenomenon of accumulation is of much larger order than heretofore admitted and bears an intimate relation with the general as well as with the local deformations of the crust and is a direct consequence and a mechanical effect of these deformations to which the term “diastrophic” has been applied. As a complement to this theory, the writer offers a new interpretation of the “rock

Antimony Assay & Determination by Roasting Stibnite

The product obtained by roasting stibnite is likely to contain some unoxidized antimony trisulphide and a mixture of antimony trioxide and antimony tetroxide. It was desired to determine, as accurately as possible, the condition of the antimony as well as the total quantity present. Attempts were made to separate the trisulphide and the two oxides by methods based upon their varying solubilities in different solvents, but no satisfactory results were obtained in this way. It was found, however, that by determining the total antimony content, the antimony present as trioxide, and the antimony present as trisulphide, a good idea of the chemical composition of the roasted product could be obtained.

The total antimony was determined by dissolving the sample in concentrated hydrochloric acid, reducing the antimony entirely to the trivalent condition by means of hydriodic acid and eventually titrating the antimony back to the pentavalent condition by means of iodine in the presence of sodium bicarbonate. The details of the procedure are as follows:

Weigh out 0.25 gram of the roasted product into a trapped flask (Fig. 1), add 4 grams of powdered tartaric acid, 2 grams of potassium iodide and 40 c.c. of concentrated hydrochloric acid. Boil the solution gently for

Cyanide Leaching Clay Ore

The ore deposit of the Buckhorn Mines Co., Buckhorn, Nev., is peculiar in being a shallow kaolinized mass of material with basalt walls, and having apparently no direct connection with any of the usual gold-bearing rocks. The average ore contains 16 per cent, water of hydration, and the cyaniding of this hydrous clayey material offered unusual difficulties as compared with the typical gold quartz ores of Nevada.

The orebody was thoroughly developed; then the mill was built according to the latest cyanide practice, with such changes as were thought to be demanded by the peculiar nature of this ore.

Upon starting the mill, the ore proved more difficult to handle than had been anticipated. It is hoped that an account of how these difficulties were met may prove of interest to anyone having a clayey ore to handle and to the profession in general.

Geology

The Buckhorn orebody lies along a north and south fault plane, of perhaps 1,000 ft. dislocation, that can be traced for miles; but the only other known mineralization consists of similar ore in the Murphy mine, a mile farther north.

The east or hanging wall is hard and smooth, being a typical fault plane. The best ore is

Conveyor Belt Calculating Chart

The accompanying chart has been drawn for the convenience of engineers as a means of quickly determining the correct number of plies of conveyor belts operating under specific conditions.

The calculations are based on the average safe strength (factor of safety, 15) of the various standard rubber conveyor belts.

The calculations assume maximum loading conditions; that is, the belt is considered as carrying the greatest load that it will handle without spillage at ordinary belt speeds. This not only produces the most economical operating conditions, but also the maximum tension in the belt.

The chart is a graphical representation of the formula :

Where, p = kgW(L + 10H)
p = the correct number of plies
k = a constant, depending on the type of drive
g = the weight in pounds per cubic foot of material handled
W = the width of the belt in inches
L = the length of the belt in feet (approximately twice the center distance).
H = the difference in elevation between the head and tail pulleys, in feet.
For a simple drive, with a bare pulley, k = 1/250,000
For a simple drive, with a rubber-lagged pulley, k = 1/300,000
For a tandem drive, with bare pulleys, k = 1/375,000
For a tandem drive, with rubber-lagged pulleys,

Marathon, Chilean and Hardinge Grinding Mills Comparison

During 1914 and 1915 extensive experiments were conducted at the concentrator of The Detroit Copper Mining Co. of Arizona, at Morenci, Ariz., in order to test the relative grinding efficiencies of the Marathon, the Chilean and the Hardinge Mills.

The Marathon mill used in the experiments,was the first one ever built by the manufacturers; and since this was the first time that it was given a thorough tryout, with such remarkable results, the data have been assembled in the following paper and submitted in the interests of the miffing profession.

Description of the Flow Sheet

The concentrator flow sheet, as it existed at the time of these tests, is shown in Fig. 1. The total mill feed, as delivered from the crushing plant, had as its maximum size 1-in. material. This material was screened dry on Cole Zig-Zag screens fitted with 4-mesh openings; the oversize going to one pair of coarse rolls, the undersize to five Wilfley tables fitted with Butchart National riffles. The coarse-roll product was elevated and screened wet on Zig-Zag screens fitted with 4-mesh openings, the undersize going to the five tables mentioned above and the oversize to one pair of fine rolls.

The fine-roll product was elevated and screened

Casting Metal Rods

In view of the circumstance that very few important changes have been made within the last 15 or 20 years in the equipment of rod and wire mills, the description of a new process introduced by Grenville Mellen, of Llewellyn Park, N. J., to take the place of the present laborious system of producing rods of lead, zinc, brass, copper, aluminum, etc., may be interesting to members of the Institute. This new process consists in the production of cast rods at one operation in a small continuous casting machine.

The hot liquid metal is transferred from the melting crucibles directly into an endless chain of mold blocks in the machine, where solidification takes place, and the rod comes out continuously in a solid form at one end as long as the molten metal is supplied. The operation of these mold blocks so as to produce a solid rod of uniform structure constitutes an important part of Mr. Mellen’s invention.

The machine (Figs. 1 and 2), 12 ft. in height over all, 2 by 3 ft. in horizontal cross-sectional area, and 6,000 lb. in weight, has a framework of cast iron, holding in position two endless chains of mold blocks, which are made

Hardinge Conical Mill Capacity

The following conclusions on the work of the Hardinge mill are based on data furnished to the writer by the Hardinge Conical Mill Co. in the form of the mesh cards hereto appended. Energy units (E. U.) and relative mechanical efficiencies (R. M. E.) are computed by the “volume method” of Stadler. Screen apertures used are the average apertures of testing screens of the meshes given.hardinge-conical-mill-danish-pebbles

Card 122. June 28, 1912. Vipond Porcupine Mines Co., Ltd., Schumacher, Ont., Canada.
Ore from mill bin. Gangue, quartz and basalt.
4.5 ft. by 13 in. ball mill,
Capacity, 48 tons per 24 hr.
Charge, 4,000 lb. balls.
Speed, 33 rev. per minute.
Horsepower, 15 to 17.
Water, 100 per cent, by weight. (50 per cent. ?)
Product deslimed and oversize reground in pebble mill, see Card 113.
Feed to mill through 2-in. mesh.

hardinge-conical-mill-mesh

Card 107. Jan. 30, 1912. Miami Copper Co., Miami, Ariz.
Material from mill bin. Gangue, siliceous porphyry.
6 ft. by 16 in. ball mill.
Capacity, 351 tons per 24 hr.
Charge, 4 tons balls.
Speed, 28 rev. per minute.
Horsepower, 35 net.
Water, 50 per cent, (approx.).
Elevation of feed end, 2 in.
Consumption of balls, 0.578 lb. per ton of ore crushed.
Feed to mill through

Oxidizing Roast; Stibnite the Antimony Mineral

The leading antimony mineral is stibnite. In smelting stibnite ore two processes are available, precipitation and roasting-reduction. The former is suited, only for high-grade ores. As low-grade ores are more common than high-grade, roasting-reduction is of greater importance than precipitation. In the roasting process the aim may be to leave the oxidized antimony in the ore, or it may be to volatilize as much of the antimony as possible, collect the volatilized oxide as a rich intermediary product and smelt it for antimony, leaving the gangue poor enough to be considered a waste product.

Whichever way the roast is conducted certain difficulties inherent in stibnite are encountered. These are:

  1. The low melting point of stibnite which; according to Pelabon, is 550°C., according to Wagemann 540°C., and according to Borgstrom 546°C.
  2. The ignition temperature: According to Friedrich, stibnite, if heated in air, begins to oxidize at 290°C. if the size of a grain is 0.1 mm. in diameter; at 343°, if 0.1 to 0.2 mm.; and 430° if 0.2 mm.
  3. The fusibility of a mixture of Sb2S3 and Sb2O3 which in the form of kermesite (Sb2S3)2.Sb2O3 melts at 517°C.
  4. The volatility of Sb2S3 and Sb2O3, for which no numerical data appear to

Smelting of Lead Ores using High Lime Slags

Anton Eilers, who was then interested in the lead smelting and refining business near Salt Lake City, Utah, made a somewhat radical departure from the regular practice at that time, which was to use but little lime in the slag, with a high percentage of iron. Lime was not only a cheaper flux than iron, but it enabled the metallurgist to make a more siliceous slag, an economical advantage in smelting where the smelting companies had to purchase either iron or lime to neutralize the excess silica, and penalize the ore shippers accordingly. The larger amount of both lime and silica in the slag also made it of lighter specific gravity, and a better separation of the metals and mattes was secured. This change in the formation of slags for lead smelting was brought about by Anton Eilers, prior to the Leadville mining excitement. We must also give Mr. Eilers credit for the general introduction of the hollow water-cooled cast-iron jacket for the blast furnace.

Again referring to the use of more lime and less iron in the formation of slags, there is no doubt but that it prevents the formation of a great many so-called “sows” in the lead crucible,

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