[CONTRIBUTION FROM THE MASSACHTJS~TTS INSTITUTE O F TECHNOLOGY.]
REVIEW OF AMERICAN CHEMICAL RESEARCH. VOL. VII.
No. 9.
ARTHURA. NOYES,Editor ; A. G. WOODMAN,Associate Editor. REVIEWERS:Analytical Chemistry, H. P. Talbot and F. J. Moore; Biological Chemistry, A. G. Woodman ; Carbohydrates, G. W. Rolfe ; General Chemistry, A. A. Noyes ; Geological and Mineralogical Chemistry, W. 0. Crosby and C. H. Warren; Inorganic Chemistry, Henry Fay; Metallurgical Chemistry and Assaying, H. 0. Hofman ; Organic Chemistry, J. F. Norris ; Physical Chemistry, H. M. Goodwin ; Sanitary Chemistry, E. H. Richsrds; Industrial Chemistry, A. H. Gill and F. H. Thorp.
AETALLURGICAL CHEnISTRY. H. 0. H O F M A I , REVIEWER.
The Department of Mining and Metallurgy at the AcGill University, Aontreal. BY CORRESPONDENT.Ezg. Mix. J., 71, 514-516.-The paper describes with much detail the new mining and metallurgical laboratory, giving a plan of the same, and discusses in a general way the history of the department and its methods of instruction. Stamp Milling of Free Gold Ores. BY D. HARMON.Min. Sa*.Press, 82, 556-56o.-The paper discusses, with illustrations, the practical details of milling gold ores ; they are more of a mechanical than of a chemical nature. Electro-Silvered Versus Plain Copper Plates. BY J. R. COOPER. Eng. Min. J . , 71, 331.-In the extraction of gold from its ores by means of the batteryamalgamating process, electro-silvered plates have replaced in most instances the plain amalgamated copper plates, as the latter become more or less tarnished with copper salts, which prevent amalgam or quicksilver from adhering. The author calls attention to the fact that all copper contains more or less cuprous oxide, and that, as this oxide does not combine with quicksilver, a plain copper plate can be only imperfectly amalgamated. Even if at first the whole plate is coated with quicksilver, this will break off from the oxidized parts and the latter be exposed to the action of water, oxygen, carbonic acid, etc. Mackay's Amalgam Press. BYTHEEDITOR.E n g . Min. J., 71, 83-84.-The paper is an illustrated description of a pistonpress worked by steam, air, or water. I t removes in a better way than is possible by ordinary means the surplus quicksilver
132
Review of Amevicait Chemical Research.
from amalgam, thus enriching the amalgam and reducing the amount to be retorted.
When to Begin Treatment of Cyanide Tailings. BY H. M. CROWTHER. Ezg. Min. J . , 70, 732.-The tailings coming from mills which leach gold ores with potassium cyanide always retain more or less gold. If rich enough, they are re-treated directly, if not they go to waste or are perhaps stored to be re-treated at a later date, when the cost of working will be lower on account of the cheapening of labor and materials. The author found that by simply rewashing tailings from three to twelve months old from the dumps of the Mercur mine, Utah, containing 13.2 per cent. water and assaying $1.05, he obtained an extraction of 53.3 per cent. of the gold. Tailings usually retain at least 4 lb. of potassium cyanide and somewhat more free caustic alkali per ton. If care is taken to add to the last wash-water from one to several pounds of caustic alkali the tailings will retain sufficient alkali to protect the residual potassium cyanide and allow it to have its solvent effect upon the residue in the tailings, which are being slowly affected by the action of air, moisture, and warmth. The Agitation Process for Cyaniding Slimes. BY C. S. HURTER. Eng. Min. J , , 71, 82-83. Discussion. BY J . F. WEBB. (bid., 144.-The paper is an illustrated description of the manner in which the pneumatic cyanide process is carried out a t the works of the Cochiti Gold Mining Co., near Bland, N. 31. Low-grade slimes, of which ninety-six per cent. will pass a IOOmesh sieve, are treated at a cost of $1.00 a ton with an extraction of eighty per cent. The slimes are agitated (in 3 to 3 ; ton charges) in tanks nine feet in diameter and five feet deep (holding six tons solution with 0.15per cent. potassium cyanide) for twenty-four hours with steam and compressed air which pass into the solution through a number of perforated pipes placed along the bottom of the vat. About sixty pounds of lime are charged into a wire bucket suspended to reach below the surface of the solution. T h e lime not only neutralizes any acid reaction of the pulp, but also aids later in settling the slimes. After treatment the pulp is run from the agitating tanks into ‘ ‘ wire” settling tanks, placed in series, from which the overflow is made to pass through upward-filtering tanks before it goes to the zinc boxes. From the settling tanks the slimes are sluiced out into decanting tanks and allowed to settle for from twelve to twenty-four hours ; the clear solutions, drawn off through openings in the side, are mixed with the liquors from the ‘ ‘ wire” settling tanks before they pass through the filtering tanks. One man in a Io-hour shift can do the work of a 20-ton plant ; for agitation one-tenth of one horse-power a day is required per ton of ore. The consumption of reagents per ton of ore is one
f i e f alluvgical Chemistry.
I33
pound potassium cyanide, twenty pounds lime, and one pound zinc. T h e cost of treatment is as follows :
............................... ....................... ................................... .......................................
Cyanide, I Ib. a t 31c. Lime, 20 lbs., a t $18 per ton Zinc, I lb. a t 12c. Tramming.. Power, 0.I H. P. a t 40c.. Labor, 0.05 day a t $3.50.. Extras, repairs, smelting, etc.
............................ ........................... ...................... Total cost per ton of pulp treated.. ..............
$0.31
0.18
0.12
0.04 0.04 0,175 0.I35
$1.00
The Riecken Process for Treating Telluride and Sulphide Ores. BY H. R. CASSEL. Eng. Min. I., 70, 664 ; 71, 47.This process aims to extract coarse and fine gold from raw or roasted ores by means of a combination of amalgamation and lixiviation with potassium cyanide in a manner somewhat similar to that attempted in the electrochemical process of PelatanClerici. T h e apparatus used consists of a horizontal stationary tank with stirring shaft having beaters. T h e tank, open at the top, has vertical ends, inclined sides, and a rounded bottom. T h e sides and bottom are lined with removable amalgamated copper plates, forming the negative pole ; the positive pole is stationary. A small pump, drawing its supply from a trap at the bottom of the tank, causes quicksilver to flow continuously over the amalgamated plates. T h e ore is charged with quicksilver and a dilute solution of potassium cyanide into the vat ; the coape gold is amalgamated and the fine gold dissolved and electrically precipitated on the quicksilver cathode. Pyritic Smelting and Hot Blast. BY S. E. BRETHERTON. Eng. Min. I., 70, 760-761.-The author, a strong advocate of pyritic smelting, claims that in comparison with lead smelting, pyritic smelting saves as high a percentage of gold and silver with a concentration of 8 to 15 tons of ore into I of matte with 50 to 60 per cent. of copper ; that it permits a higher degree of concentration in working ores with I to 2 per cent. copper ; and that it allows a larger percentage of zinc in the charge as well as a more silicious slag. T h e charges run by the author, using hot blast, contain 3 per cent. copper and over, 20 to 30 per cent. iron, 8 to 13 per cent. lime, not over I O per cent. zinc, I O per cent. alumina, 30 to 36 per cent. silica, I O to 30 per cent. sulphur. Pyritic Smelting and Hot Blast. BY A. E. BRETHERTON. Eng. Min. I.,71, 458..-The main point of interest in this paper is a dimensioned drawing of the author’s blast-furnace and forehearth, with air-chamber and flues for superheating the blast by means of the waste heat of the fused matte and slag collecting in the fore-hearth.
I34
Review of American Chemical Research.
The Province of Pyritic Smelting. BYH. LANG. E n g . Miw. J . , 7 f , 589-590 ; 617-61S,-Pyritic smelting may be defined as a matting blast-furnace smelting process in which parts of the metallic sulphides are oxidized, thereby giving a more concentrated product. T h e degree of concentration depends mainly on the proportion of silica in the charge. As the silica increases the matte-fall decreases, as does also the smelting power, because slags when acid run more slowly than when basic. Thus a furnace with a charge rich in pyrite, run to form a basic slag, will give much low-grade matte and put through large quantities with little fuel. At Tilt Cove, Newfoundland, 3 tons pyrite were concentrated into I ton of matte, the furnace running without any coke and with cold blast. At Mount Zyell, Tasmania, heavy pyritic ore with 3 per cent. copper is smelted with silicious flux to a matte containing over 2 0 per cent. copper, i. e., a concentration of six into one. The matte is smelted pyritically with silicious flux (raising the tenor of copper to 50 per cent., i. e., a concentration of 2 ? ~tons into I ) when it is Resseinerized. A furnace with a charge containing 3j per cent. pyrite, which is run to form an acid slag, will give a concentration of eight into one and put through a considerable amount of ore, but it will require about 5 per cent. coke and a blast heated to 2j0O C. X furnace running a charge with a deficiency of sulphides, or with a slag that is very silicious, loses most of its pyritic character and requires, of course, much largerquantities of coke, from I O to 2 0 per cent. In pyritic work two-thirds of the coke can be replaced by the use of hot-blast. The Leaching of Copper Ores. BY J . OHLT. Min. Sci. PFms, 82, 51-61.-This paper is a partial review of the subject written for the general public. Some of the reactions said to take place in roasting previous to leaching are at least doubtful ; thus sodium sulphate and cupric silicate, when subjected to an oxidizing roast, will hardly form sodium silicate and cupric sulphate. nodern Leaching Processes. BY J . OHLY. Milt. Sei. Pwss, 82, 168-169.-The general character of this paper is similar to that of the preceding one. Name Plates. BY E. S. SPERRY.A / . Woda', 7, 74-75.Name plates, i. e . , plates bearing the names of manufacturers of machinery, are usually cast of bronze or of aluminum ; brass is sometimes used, but its color is not so pleasing as that of bronze ; iron plates are unsightly. I n order to obtain the right color the composition of the bronze is somewhat limited. T h e two following mixtures, copper go per cent. , tin 8 per cent. , zinc 2 per cent., and copper 92 per cent., tin 3 per cent., and zinc 5 per cent., give satisfactory castings. An alloy of aluminum with 6 per cent. copper also works well. T h e paper gives some practical details about casting these alloys.
Metallurgical Chemistry.
=35
Method ot Making Alumina. BY C. M. HALL. Al. World, 7, 75-76.-The new method of producing pure alumina consists in charging bauxite (calcined at a low heat if necessary), burnt lime, sodium carbonate, and water into a digester provided with a stirring mechanism and subjecting the mixture a t a considerable pressure to an elevated temperature for from one to three hours. Insoluble carbonate and silicate and inert impurities of the bauxite, such as iron oxide, insoluble alumina, etc., will form a residue to be separated by filtration from the soluble sodium aluminate. From the latter, aluminum hydroxide is precipitated in the usual way by carbonic acid and filtered off ; the filtrate, with its sodium carbonate, is concentrated by heating and used again with another charge. Aluminum-Zinc Alloys. BY J. W. RICHARDS. Al. World, 7 , 153-154.--Alloys containing equal parts of zinc and aluminum or more zinc than aluminum have no specially valuable mechanical properties ; the case is different when aluminum prevails over zinc. The alloy 2 parts aluminum to I part zinc, that is, with 334 per cent. zinc, is remarkable. According to Durand (Science, 1897,p. 396), its strength equals that of cast-iron ; it melts at about 425' C., fills the joints of a mold perfectly, does not oxidize readily, and takes a fine finish ; it is brittle, but resists corrosion well. T h e author adds to the above that while his first castings showed a breaking strain of 18,000 to 24,000 pounds per square inch with no perceptible elongation, he has no difficulty at present in securing a tensile strength of 40,000 pounds. Such a casting resembles a high-carbon steel ; it, however, works well under tools and does not require any lubrication. Its high specific gravity of 3.8 shows that a great contraction has taken place in the formation (viz., 17 per cent.), which suggests a cause for its great strength. The alloy, 3 parts aluminum to I part zinc, that is, with 25 per cent. zinc, is the one most commonly used. It is softer than the alloy with 334 per cent. zinc, has a tensile strength of 35,000 pounds, and is less brittle ; its specific gravity is 3.4, showing a contraction of 14 per cent. With alloys containing less than 25 per cent. zinc, the strength and hardness decrease quickly ; an alloy with I O per cent. and less zinc can be forged, rolled, and drawn. The Dominion Iron and SteelCo., Limited. BYC. KIRCHHOFF. Zron Age, 66, 18-22.-The paper is an illustrated description of the new iron and steel works in the process of erection near Sydney, Cape Breton. It will consist of four blast-furnaces (85 feet high, 20-foot bosh), ten 50-ton open-hearth furnaces, a 35-ton blooming mill, a coal-washing plant, and 400 Otto-Hoffmann byproduct coke-ovens. The ore mined on Great Bed Island, Newfoundland, contains H,O, 1.50-2.50 ; Fe, 54.43-57.84 ; SO!, 9.34-13.00 ; P, 0.744-0.835 ; S, 0.05-0.03. Good limestone is
136
Review
,4merican Chemical Research.
quarried near the works. The following analyses are given as being characteristic of the unwashed and washed coal of the leading mines of the Dominion Coal Co., and of the coke produced from the washed coal. GENERALCOALANALYSIS. Raw coal.
Reserve mine.
cent. ..............Per1.45 ........ 32.45 .......... 60.45 ................ 1.64
Moisture.. Volatile matter.. Fixed carbon.. Sulphur Ash. ....................
Calrdonia mine. Per cent.
Dominion mine. Per cent.
1.54 70.86 62.91 1.50 4.69
31.89 61.49 1.56 5.41
5.65
1-21
Washed coal.
RIoisture ................ I .OI Volatile matter.. 52-99 Fixed carbon.. 62.21 Sulphur 1.11 Ash.. 3.79
I .os 33.92 61.69 1.07 3.3'
0.91 6.07
0.78 5.38
........ ..........
................ ................... Retort coke. Sulphur ................ Ash. ....................
0.84
37.86 62.60 1.17 4.50 1.01
6.24
Heat and Power from the Waste Gases of Blast-Furnaces. BY F. W. GORDON.Iron A g e , 66, 1-6.-The paper shows which part of the total heat generated by an iron blast-furnace is required by the furnace itself, and which is available for other purposes. The calculations are based on data of one of the South Chicago blast-furnaces published by the author in 1885 ( T r a m . A m . Inst. Min. E n g . , 14,3 6 2 ) . Cast-Iron Car-Wheels. BY G. W. BEEBE. I ~ o i tTrade Rev., 33, 16-17.-'I'he author calls attention to the small amount of damage done by the failures of cast-iron car-wheels, when it is considered that 10,269,924 such wheels are in use at present. H e attributes this fact to the close inspection and to the thermal and drop tests exacted by the railroad companies, both of which are described in detail with illustrations. The thermal test requires that a sample wheel of a melt when cast under specified conditions shall not crack upon cooling ; the drop test requires that the wheel, supported in a certain definite way, shall stand a number of blows from a hatnmer weighing IOO to 140 pounds and lifted 7 to 12 feet. The subjoined table gives the chemical composition of wheels that withstood the physical tests and that did not : Wheels that failed in thermal test. Max. Min.
Wheels that stood thermal test. Max. Min.
3.03 2.92 0.89 0.71 o . 0 ~0.042 0.60 0.49 0.82 0.50 0.48 0.39
3.90 2.98 0.92 0.60 0.58 0.91
0.67 0.080 0.48
0.52
0.26
.... 3.02 3.91
Totalcarbon Graphiticcarbon. Combined carbon Salphur Manganese Silicon Phosphorus
......... ...... ..........
......
3.38
2.71
0.50
Wheels t h a t failed under 50 blows, Barr drop. Max. Min.
3.87 3.19 0.68 0.080 0.62 0.97 0.58
Wheels t h a t stoodsoblows and over, Barr drop. Max Min.
3.42
3.93
3.49
2.90
3.02
2.90
0.52 0.020
0.40 0.67 0.30
0.91 0.59 0.070 0.05 0.72 0.47 0.68 1.10 0.53 0.28
.
GeologicaI and MineraZogica I Chemistry
I37
The Tropenas Process for Steel Castings. BY THEEDITOR. Foundry, 17, 237 ; Eng. Min. I., 70, 761.-The paper contains a brief description of the Tropenas process with illustrations of converter and of castings. Influence of Copper in Retarding Corrosion of Soft Steel and Wrought Iron. BY F. H. WILLIAMS. Eng. SOC.Western Pa., 26, 231, through Iron Age, 66, 16.-The experiments described were carried out in order to show what effects small additions of copper would have in retarding the corrosive effect of moisture on soft steel and wrought iron. For this purpose the specimens were cut and filed to the same dimensions, weighed, suspended on a frame, dipped together into water, and then left to hang in the air until dry. This treatment was repeated several times a day for a month, until the oxide-scale formed showed a tendency to peel off. The specimens were freed from oxide and then weighed. I n the table below are given the percentage losses : L O S S FROM
ATMOSPHERIC CORROSION. Loss in weight. Per cent.
....................... .... ..... ....
A-Soft Bessemer steel B-Soft Bessemer steel with 0.078 copper.. C -Soft Bessemer steel with 0.145 copper D-Soft Bessemer steel with 0.263 copper..
1.85 0.89 0.75 0.74
STEELAND WROUGHTIRON. in weight. Per cent.
1,oss
.......................... ..................... .....................
Soft Bessemer steel Wrought iron, sample I . . Wrought iron, sample 2 . . Wrought iron, sample 3 Wrought iron, sample 4 (containing 0.393 per cent. copper).
......................
..............................
1.65 0.76 0.80
0.87 0.53
They show that both soft Bessemer steel and wrought iron resist corrosion much better when they contain some copper than when they do not.
GEOLOGICAL AND MINERALOGICAL CHEnISTRY. W. 0 .
CROSBY,
REVIEWER.
On the Constitution of Barytocelestites. BY C. W. VOLNEY. J. A m . Chent. SOC.,21, 386-388.-Although previous work had discredited the existence of a true barium-strontium sulphate, showing only barites containing a trace of strontium or celestites containing a trace of barium, the author finds this mineral from eastern Ontario to yield : BaSO,, 30.850, and SrSO,, 70.010. A previous analysis by the author had given : BaSO,, 39.850, and
