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By Monte J. Pool, Rudolph Speiser, George R. St. Pierre, William T. Ebihara

Standard free energies of formation of WO,, W O W20058 and WO3from oxygen and the lower oxide or tungsten have been determined in the tempel-ature range of 700° to 1220°C. A tentative W-O phase diagmm is presented based on the evidence that the oxide phases, "W18O49" and "W20058", are unstable at l~atm total pressure, below 585° and 485°C:, respectively. A HE need for a complete quantitative treatment of the phase equilibria of the W-O system has been establishedby metallurgists during the past few years. In an attempt to improve the endurance of tungsten exposed to oxidizing atmospheres at high temperatures, many research groups have studied the kinetics of tungsten oxidation. The reverse process, the reduction of the tungsten oxides to metal, has also been investigated to some extent. Regardless of the particular interest, metal to oxide or oxide to metal, a knowledge of the phase equilibria of the W-O system is required to properly interpret all of the kinetic observations. It should be possible to state the stable phases of the W-O system at any given values of the chemical potential of oxygen and the temperature.

Jan 1, 1962

By W. B. Potter

There is probably no more interesting group of mineral fuels to be found in any country than that occurring within the limits of the new State of Colorado. The supplies are so abundant, and the occurrence and distribution are so favorable for easy development and transportation to the future manufacturing centres of the State, that they are destined to play a very important part in the material growth and prosperity of the region, the more so because of the rich and varied stores of ores awaiting metallurgical treatment, and the comparative scarcity of timber for fuel. From a purely scientific point, also, these lignitic coals form an interesting and important series. An examination of their geological occurrence and relations opens up new and important questions regarding the comparative value of various kinds of geological evidence, while a study of the character and composition of this class of fuels, which forms a connecting link, as it were, between the lignites and the true bituminous coals, may lead to a more thorough and accurate classification of mineral fuels. The analyses here presented are from samples, of not less than fifty pounds each, obtained by myself during the summer of 1875, and may be regarded as representing very fairly the average run of

By Georges Fleming

The new burden preparation plant of ARBED Luxembourg, Belval- Works, which comprises 2 large sinter strands, is equipped with a process computer connected to a comprehensive process control system. The main jobs done by the computer are the control of the raw mix composition, and thus the monitoring of the stacking of the piles at the bed-blending plant, and the optimization of the sintering process. Among the optimization criteria, quality is considered as the most important. The sinter quality, characterized by the mechanical strength and the state of oxidation, is controlled automatically. The control system which we have dev loped is highly reliable; as a result, the standard deviation of Fe++, for the control of bivalent iron, has been narrowed to 0,5 % and the standard deviation of the IS0 + 6, 3 mm index, for the control of the mechanical strength, has been kept within 1 %. Thanks to these results, the combined savings in fuel consumption at the sinter plant and at the blast furnaces have covered the total costs of the optimization project in 2 years. By applying automatic control, the optimum driving range of the sinter plant has been defined and these new guidelines are used for monitoring the sinter production.

Jan 1, 1977

By Ian Wark

MERCAPTOBENZTHIAZOLE and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium mercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group -SH or -SNa. The general method of investigation has been based on contact tests. Two temperatures, 10° and 35° C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Ian William Wark, Keith Leonard Sutherland

MERCAPTOBENZTHIAZOLE and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium mercaptobenzthiazole and for sodium ethyl xanthate are: [ ] Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group -SH or -SNa. The general method of investigation has been based on contact tests. Two temperatures, 10º and 35º C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Keith Sutherland

AEROFLOAT 25 is a complex mixture of free cresylic acid with aryl substituted dithiophosphoric acids, sulphides, disulphides, etc. Its complete composition has not been published by the makers or patentees. It is prepared1 by the reaction between phosphorus pentasulphide and carefully selected cresylic acid. We have been informed that this acid contains no phenol and very little cresol, and that it is rich in the higher alkyl phenols, particularly the xylenols. The reaction between a phenol ROH and phosphorus pentasulphide may produce compounds of the following type:2 (i) RO S P Diaryldithiophosphoric acids RO SH (ii) R-SH Thiophenolic compounds (iii) R-S-R Diaryl sulphides (iv) R-S-S-R Diaryl disulphides (v) Substituted thianthren compounds Except for the simplest type, the thiophenols (ii), the boiling points of these compounds lie above 300° C. The amounts of the thianthren compounds formed from the five xylenols (if all these are present) will vary according to the position of the substituents. In an attempt to ascertain something of the nature of the reagent, fractional distillation under atmospheric pressure was undertaken. At the outset, hydrogen sulphide was freely evolved, and-particularly below 200° C.-the fractions had the strong odor characteristic of the

Jan 1, 1939

By W. B. Potter

THERE is probably no more interesting group of mineral fuels to be found in any country than that occurring within the limits of the new State of Colorado. The supplies are so abundant, and the occurrence and distribution are so favorable for easy development and transportation to the future manufacturing centres of the State, that they are destined to play a very important part in the material growth and prosperity of the region, the more so because of the rich and varied stores of ores awaiting metallurgical treatment, and the comparative scarcity of timber for fuel. From a purely scientific point, also, these lignitic coals form an interesting and important series. An examination of their geological occurrence and relations opens up new and important questions regarding the comparative value of various kinds of geological evidence, while a study of the character and composition of this class of fuels, which forms a connecting link, as it were, between the lignites and the true bituminous coals, may lead to a more thorough and accurate classification of mineral fuels. The analyses here presented are from samples, of not less than fifty pounds each, obtained by myself during the summer of 1875, and may be regarded as representing very fairly the average run of

Jan 1, 1877

By A. Donald Kelmers, Forest G. Seeley, B. Zane Egan

INTRODUCTION Coal ash, presently the fifth most abundant of the solid minerals produced in the United States, is expected to become the fourth most abundant by the end of this decade (1). The production of fly ash from the combustion of pulverized coal amounted to a total of 44 million metric tons (Mt) in 1977 and is expected to Increase to 91 Mt by 1985. Coal ash, which results from the Inorganic clay and mineral content of the coal, contains several elements and thus can be considered as a mined and crushed mineral resource rather than a waste material Furthermore, potential problems associated with fly-ash disposal ponds and the leaching of potentially hazardous elements through groundwater infiltration and/or rainfall provide additional incentive for processing fly ash for environ- mental control as well as for the recovery of certain metal values. Fly ash could provide an abundant domestic source of aluminum and several other metals Aluminum is now recovered from bauxite, and over 90% of this ore is imported since domestic sources are limited and cannot meet the U.S. demand There is a close relationship between the aluminum content of fly ash and the domestic consumption of this metal (Table 1).

Jan 1, 1981

By D. A. Dahlstrom

THE necessity for slime elimination from valuable mineral and coal products has become increasingly significant within the past 5 years.' , Most of the mechanized mining and present beneficiation methods have resulted in larger tonnages of extreme fines, silts, and clay, commonly called slimes, processed by the preparation plant. Economics in turn have forced the plant operator constantly to lower the bottom size of effective beneficiation, necessitating an almost complete recovery of valuable solids regardless of particle size. When these important factors are considered, the need for an efficient slime removal method for fine solids becomes self-evident. Ordinarily slimes have been classified as ranging from 75 microns, or 200 mesh, down to colloidal dimensions of less than one micron. At the same time there is general agreement that the most troublesome slimes are primarily clays, silts and extreme fines, so that the actual top size may be placed at approximately 30 to 40 microns. This immediately restricts any desliming operation to classification, as screening or other methods would be both uneconomical and grossly inefficient at such dimensions. The liquid-solid cyclone has been recognized as one of the most efficient fine size classifiers available to the mining industry. Applications of cyclones to thickening, high efficiency solid recovery, degritting,

Jan 1, 1953

By Stephen Birch

THE Chitina mining district of Alaska is located at the headwaters of the Chitina and Copper Rivers. At present, the only producing min-ing properties are the mines of the Kennecott Copper Corpn. and the Mother Lode Coalition Co., which are situated 196 miles from Cordova the port of entry. The first claims, later acquired by the Kennecott Mines Co. and afterwards transferred to the Kennecott Copper Corpn., were discovered in 1900. The Copper River & Northwestern Ry., which connects the mines with tide water at Cordova, was completed in the spring of 1911. Contemporary with the construction of the railroad, aerial tram equipment was brought to the mines by pack train and a tramway, 3 miles, long, connecting Bonanza mine with the proposed railroad terminal, was finished, enabling shipments of high-grade ore to be made immediately on the completion of the railroad. A mill to treat the lower grade ore was begun the same year. The Kennecott company's holdings consist of 111 mineral claims. The Mother Lode Coalition Mines Co., which is controlled by the Kennecott Copper Corpn., owns 73 claims adjoining the Kennecott holdings. All data on operations and geology refer equally well to the Mother Lode property.

Jan 1, 1924

By Ian William Wark, Keith Leonard Sutherland

Mercaptobenzthiazole and its sodium salt are marketed under the trade names Flotagen and Flotagen S respectively, for use as collectors for cerussite and other minerals. The structural formulas for sodium rnercaptobenzthiazole and for sodium ethyl xanthate are: Chemically there is a resemblance between the two compounds, though the free acid (mercaptobenzthiazole itself) is much more stable than xanthic acid. Both are readily oxidized, e.g., by iodine to disulphides, and can be estimated by iodometric titration. Qualitatively they are similar as collectors in flotation, although there are quantitative differences between them that may be important in practice. It is deduced that the influence of the nitrogen atom is subordinated to that of the sulphur atoms, and that the dominant group of these compounds is the mercapto group —SH or —5Na. The general method of investigation has been based on contact tests. Two temperatures, 10" and 35" C., have been chosen, and with a standard concentration of 20 mg. per liter of mercaptobenzthiazole (i.e., of the free acid) the influence of alkali, cyanide and copper sulphate on contact at sulphide mineral surfaces has been studied. This standard concentration corresponds to about 19 mg. per liter potassium ethyl xanthate; it brings out the differences between the minerals better than a higher concentra-

Jan 1, 1939

By Jerome C. Motz

Primary Crushers The types, sizes and number of crushers employed in a complete reduction system will vary with such factors as the volume of ore to be processed, the size of the mine-run lump material, the hardness of the ore bearing rock and the size and dimension required for the final product. Basically, for primary crushing there are only three distinct types of crushing equipment. These are the Jaw crushers, Gyratory crushers and Impact crushers, and they each have their own distinctive operating characteristics. Jaw crushers operate by squeezing the rock between the fixed and the movable sides of a tapered cavity. Variations of pitch and swing have been tried, but most Blake-type machines have a crushing angle of about 27° between swing and stationary jaws. The principle of which Gyratory crushers work is very simple. If a Cone is mounted on the upper end of a vertical shaft and the top of the shaft is held .stationary while the lower end is rotated eccentrically, the Cone will also swing eccentrically. If the Cone is enclosed in a suitable housing, it will swing toward and away from the housing walls-as it rotates. If the done and the housing walls are sufficiently strong and heavy, anything caught between them will be crushed.

Jan 1, 1978

By J. J. Kramer, W. A. Tiller, G. F. Bolling

The temperatures of solid-liquid interfaces have been measured during the growth of Sn-Pb alloy crystals which exhibited a cellulur substructure. A simple descriptive theory was used in combination with this data and the other measurable growth variables to predict some features of the solute segregation such as the intercell excess concentration and the depth of cell grooves during freezing. The effective distribution coefficient at the tip of a cell, a, was predicted and experimentally found to vary in the range, 1 >a > k0. At the lower limit, the severe segregation that must arise between dendritic cells was substantiated by various observations such as the existence of a second Phase even for alloys of only 0.2 wt pct Pb. ThE cellular morphology of a solid-liquid interface is known to coincide with the formation of a zone of constitutional supercooling ahead of the interface during growth.' The occurrence of various cell structures, (two-dimensional cells, regular cells, dendritic cells), has been quantitatively investigated,'2,4 but the segregation of solute which arises as a consequence of this mode of growth has only been examined qualitatively. An indirect method of obtaining the solute concentration at the tip of a cell cap during solidification has been de-

Jan 1, 1963

By John P. Ashby

Mine production blasting is a process of destruction of rock masses in order that ore may be extracted. Many open pit operations are faced with the apparently conflicting requirements of providing large quantities of fragmented rock for the processing plant and of minimizing the damage inflicted upon the surrounding pit slopes. A reasonable compromise between these two conflicting demands may often be found by means of simple engineering of production blasts. Many operations tend to rely too heavily upon traditional wall control techniques to alleviate a problem already created by the production blasts. Various production trends including use of larger blastholes and patterns have tended to aggravate the situation. These practices only serve to emphasize the need for engineered improvements. Central to blasting engineering is the process of systematic trial and evaluation. Changes to the blasting system should be made singly, starting with the simplest. This paper discusses simple changes involving drill pattern control, effective use of blastholes and explosives, adequate delaying including use of down-the-hole sequential techniques, effective utilization of free faces, and avoidance of "choked" situations. By directing explosive effort where it is needed, such changes generally result in a significant improvement of slope conditions and of production blasting cost and performance.

Jan 1, 1983

By J. N. Ong, J. P. Ratledge, J. H. Boyce

Since German operators opened the Tsumeb mine in the early 1900's, continuous operation has been interrupted only by enforced shutdowns during two world wars and the depression of the 1930's. Original metallurgical practice was blast furnace smelting. This was applicable only to low zinc ore, leaving large tonnages of high zinc ore to be stockpiled on the surface. A gravity concentrator using tables, buddles, and jigs operated for several years, but differential flotation of the ore did not get beyond the experimental stage. When the property was put up for sale by the South African Custodian of Enemy Property there was an estimated 434,000 tons of ore on surface dumps. The dump material, assaying 4.48 pct Cu, 15.8 pct Pb, and 10.9 pct Zn, had become highly oxidized during a stay of many years on the surface. But these dump ores had to be used in evaluating possible metallurgy because the shaft became flooded after the 1940 shutdown and underground ore was unavailable. Many companies examined Tsumeb but quickly lost enthusiasm because of the formidable metallurgical problems presented by the dump ore. However, on the basis of extensive test work, the present company decided that differential flotation would be successful and purchased the property after competitive bidding.

Jan 4, 1955

By C. Elbaum

If a thin layer of liquid gallium is spread on a surface of solid aluminum, the gallium penetrates high-angle grain boundaries at a very rapid rate and separation along these boundaries follows. An experiment was carried out to investigate this phenomenon. A well-annealed specimen of aluminum 99.994 pct pure, consisting of several large grains was used, Fig. 1. The dimensions of the sample were 25 mm wide by 2.5 mm thick and all the grain boundaries extended through the entire thickness of the plate. This sample was prepared by strain-annealing and, as can be seen in Fig. 1, contained one long, straight boundary. An examination of the crystal orientations showed this boundary to be a coherent twin boundary. The angular misorientations between the grains forming the other boundaries were all in excess of 20 deg. A thin layer of liquid gallium was spread on one side of the specimen at about 30°C (the melting point of gallium is 29.7"C). After the application of the liquid the temperature was lowered to about 27°C. The gallium remained liquid at this temperature and it can be seen from the A1-Ga phase diagram1 that the liquid was probably saturated with aluminum.

Jan 1, 1960

By Ralph Hayden

PAGE I. IntRoduction........239 II. Definition of Anaconda SLime....240 III. The Source of Slime......240 Remodeled Flow Sheet......240 Old Plow Sheet,.......242 IV. ConStitution of Slimes......243 Chemical........243 Physical.........243 V. The Slime Problem.......247 VI. THe Experimental Slime Plant....248 VII. Slime Thickeners. ETc .......249 Slime Ponds........249 Tanks.........249 Comparative Efficiency of Open and Baffle Tanks .260 Callow Tanks........252 Kuchs-Laist Centrifugal Separator....253 Garred Filter........256 Dorr Continuous Thickener.....256 VIII. Concentrators........257 Round Table........558 Peck Centrifugal Concentrator....259 Competitive Tests.......260 Twenty-Deck Round Table..... 260 Slime Feed Distributor......261 IX. ConcluSion.........262 I. Introduction. In the wet concentration of ores there is always a certain amount of very fine material with which to contend. and which invariably carries such quantities of value that the treatment of it is worth while. commercially. This fine material usually contains that portion of the ore which hinders the separation of the mineral values: namely. the colloidal material resulting from the decomposition of certain constituents of the ore. The object of this paper is to show what efforts have been made to solve the slime problem as it occurs in the concentrator of the Washoe

Jan 1, 1914

By G. L. Oldright

THE economic manufacture of sulfuric acid by the ordinary chamber process usually involves production on a large scale and a plant that is costly to construct. The nature of sulfuric acid makes it costly to transport any great distance. For these reasons, the metallurgist has not found it feasible, at times, to beneficiate ores amenable to leaching, and a. need exists for a local process that will produce acid cheaply on a small or large scale. To leach ores containing residual sulfides, an oxidizer, such as ferric sulfate, is needed in solution. Precipitation with scrap iron is one of the cheapest methods of removing some metals from solution, giving a plant of low first cost and supplying a source of cheap ferrous sulfate. The other ingredient needed for the process is SO2 roaster gas; the addition of which, as, described below, will give both ferric sulfate and sulfuric acid. Where roaster gas is a waste or obnoxious, product, the expense. for materials is still further lessened. The use of ferric sulfate and sulfuric acid as a solvent lends itself, well to the utilization of scrap iron as a precipitant, and the stages of the process fit in well together as an economic whole.

Jan 8, 1925

By L. A. Panek

Using an approach based on the theory of similitude, the author develops a general equation and related concepts that provide new insights to an old problem. The load-bearing capacity (strength) of a square, rectangular, or cylindrical prism of a brittle material such as rock, coal, or concrete is expressed as the mathematical product of a size effect, a shape effect, and a function of the mechanical properties (deformability, cleat/joint spacing, and friction) of the pillar, roof, and floor materials. Through an application of multivariate statistical analysis, the results of assorted tests (laboratory and in situ) and observations of failed pillars can be combined into a fundamental scaling equation, which provides a unified, consistent approach to the estimation of mine pillar strength. The form of the equation is sufficiently general to be able to incorporate refinements in the characterization of the structural parameters, as they become available through future analysis and experimentation. Analysis of the published test data suggests that pillar compressive strength (per unit of area) is proportional to the cube root of the pillar width, and that the height effect can be described as the superimposing of a variable size effect (characteristic of the material) on the constant width effect.

Jan 1, 1981

By H. D. Kessler, Joseph B. McAndrew

WHEN there is occasion to make structural use of metals at temperatures above 900°C (1652°F), the choice of alloys is severely limited, and those materials which meet special requirements as to density, strength, toughness, and resistance to creep, oxidation, or fatigue at such temperatures are at a premium. Any new type of high temperature alloy which is found to be outstanding with respect to several of these properties is therefore likely to find special applications for which it is uniquely advantageous as compared to other alloys. Such is the case with the 7 titanium-aluminum alloys. This y phase is an intermediate phase based on the composition TiAl, and extends from about 35.5 to 44.5 wt pct Al at temperatures up to 1000°C, above which the field broadens to include 60 pct A1 at 1340°C.' The alloys of principal interest have a narrow melting range, with 7 forming by the peri-tectic reaction, melt + ß=y at about 1460°C. Unlike most intermediate phases, the binary alloys containing titanium and aluminum in approximately equiatomic proportion possess low room temperature hardness,' in addition to which they have low density, good resistance to oxidation, and relatively high modulus of elasticity.' Unpublished work done at Armour Research Foundation showed

Jan 1, 1957