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By J. B. Ackerman, J. D. Miller

Alunite [KA13(S04)2(OH)6] is a promising non-bauxitic aluminum resource, the domestic reserves of which are estimated to be 800 x 106 tons at 35 percent alunite. The major gangue mineral associated with alunite is quartz. The thermochemical process that has been developed for treatment of this ore does not provide for the initial removal of gangue prior to processing. In this regard, it may be desirable to concentrate the ore to gain significant technical and economic advantages. Experimental results indicate the effectiveness of an oleic acid flotation technique and exemplify the problems encountered in fine particles processing. These results show that the quality of separation studied as a function of temperature, collector addition, and depressant addition is dependent on the degree of liberation achieved during size reduction. At coarse grinds the quality of separation was limited by the presence of locked particles while for finer grinds where more extensive liberation is achieved, better separations were obtained. The degree of liberation for each size interval was determined by an SEM/energy dispersive x-ray technique and found to be independent of the extent of size reduction, suggesting that liberation occurs by indiscriminate fracture and not by detachment. Up to 89 percent liberation was realized for a minus 400 mesh grind. Under these circumstances, the quality of separation appears not only to be limited by the remaining locked particles, but, also, by contamination of the alunite concentrate with fine quartz gangue (< 2µm). The best separation for the minus 400 mesh grind was a rougher recovery of 88 percent with a grade of 65% alunite at 50°C.

Jan 1, 1980

By Ralph C. Holmer

IN the field of mineral exploration, 1956 can be looked upon as the International Geochemical Year. This is not because of unusual developments in geochemical prospecting but rather because of the world-wide effort in geochemistry and the realization that geochemistry is now an established exploration method. Use of mining geophysics has continued to increase. Those extensively employing exploration techniques indicate that developments of the past few years have permitted better programming of methods, from reconnaissance to location of drill- holes. There is greater diversification of methods- reliance is not placed on results of one. However, it is realized that often it is more economical to drill an anomaly than to conduct additional expensive geophysical surveys

Jan 2, 1957

By J. Mote, P. Ward Flynn, J. E. Dorn

The effect of strain and strain rate on the critical resolved shear stress for prismatic slip in specially oriented single magnesium crystals was determined over a range of temperatures in an effort to identify the thermally activated strain-rate controlling dislocation process. Below about 450°K prismatic slip was preceded by twinning and fracturing. Above 450°K extensive prismatic slip was obtained followed by fracturing. Neither the Peierls&apos; mechanism nor the dislocation intersection mechanism can account for the observations. The data, however, are in good agreement with the dictates of Friedel&apos;s theory for cross slip to the prismatic plane. PREVIOUS investigations on single and polycrys-talline magnesium have resulted in the identification of the mechanisms of plastic deformation summarized in Table I. The-only well-confirmed mechanisms are {0001}, (1010}, (1011) slip plus (1012) twinning. The other twinning modes were only tentatively established and additional investigations are required to further confirm their operation. As noted in Table I, slip in this hexagonal close-packed metal invariably occurs in the direction of greatest atomic density, revealing that the Burger&apos;s vector for-active slip dislocations is always given by b = a/3<1210>. Slip is easily induced on the basal plane, and recent investigations have shown that the strain-rate controlling mechanism at low temperatures is the thermally activated intersection of the glide dislocations with dislocations threading the basal plane. In contrast, very little is known about prismatic slip. It has been reported to be active at points of stress concentration in polycrystals below

Jan 1, 1962

By E. Tulcanaza

The practical significance of the in situ grade variability is usually neglected. Although recognized, often times it is either ignored or just considered as a vague guideline in many of the decisions dealing with exploration, reserve estimation, and mine planning. This paper stresses the significance of grade variability for exploration and mining, and illustrates its liaison to the structural features of the ore deposits, as well as to the mining parameters used for mine extraction. Some geostatistical results obtained from a silver mine, tungsten mine, and copper mine in South America are discussed.

Jan 1, 1985

By N. M. Levine, W. M. Fassell

In this laboratory study the problem of aerative conditioning to separate chalcopyrite and pyrite from cobaltite was simply effected with a sulfy-drate collector and pH by proper choice of mixing variables. It was shown that for a given impeller type and geometry, selectivity is governed by a relation between the Froude number and a modified power number multiplied by impeller tank-diameter ratio wherein the power factor is expressed as power intensity or horsepower per unit volume of contained pulp. In applying this approach to other systems, other criteria would be used in place of selectivity. The purpose of this paper is to show how solutions to problems of aerative conditioning of pulps may be enhanced by development of mixing parameters in a given system through application of a fundamental approach to agitation. The term aerative conditioning refers to a combination of processes which include mechanical gas dispersion, gas solution in the liquid phase, transport of dissolved gases and other reactants to the reaction zone, physico-chemico interaction within the liquid phase and/or at the solid surface, and, finally transport of products away from the reaction zone. Important elements of these processes are: 1) Air-Liquid Contact Area: This area limits the rate at which a given gas may dissolve in a given liquid. Thus, an aerative conditioning system should be designed for optimum gas dispersion. 2) Diffusional Factors: Such factors as concentration gradient, diffusion film thickness, and diffusivity may govern the rate at which dissolved constituents are transferred to the zone of interaction at a particle surface and the rate at which reaction products are transported therefrom. Thus, such systems would be designed for maximum turbulence to effect good mixing and to minimize diffusion film thickness. 3) Solids-Turbulent Liquid Contact Time: Sufficient time should be provided for interactions to take place at solid-liquid interfaces. The region of maximum turbulence for mechanical systems being in the impeller zone, it is important that the number of passes through this zone be optimized. This means that a proper balance should be struck be- tween flow and turbulent power to achieve optimum conditioning time. Too high a flow rate and insufficient turbulence may be improper if the reactions are diffusion limited. On the other hand, too much turbulent power and too little time in the reaction zone due to insufficient flow power may also be limiting. 4) Geometry and Impeller Design: The design of the conditioning vessel and the type of impeller employed are important factors in determining the relative distribution between flow and turbulent power and the degree of gas dispersion. Maximization of power input would be to no avail if the distribution between flow and turbulent power were improper or gas dispersion insufficient. 5. Physical Chemistry: The reactions between dissolved gases and solid surfaces may be limiting if gas solubility, activation energies and/or free energies are not favorable. J. H. Rushton, E. W. Costich, and H. J. Everett&apos; have summarized the mechanical elements of the combination of processes listed in a fundamental mixing equation. This equation was derived by dimensional analysis and relates the physical variables for a single impeller, centered in a cylindrical, vertical axis, flat-bottomed tank. It is, where T is tank diameter in feet; H is liquid depth in feet; C is height of impeller off tank bottom in feet; S is pitch of impeller; L is length of impeller blades; W is width of impeller blades; R is number of baffles; D is impeller diameter in feet; Np is the power number, pg/dN3D5; P is power in foot-pounds per second; g is the gravitational constant, feet per second; J is width of baffles; B is number of im-

Jan 1, 1961

By R. C. Schmidt, B. E. Kennedy

The Mont Klahoyo magnetite deposit is located about 600 km (373 miles) northwest of Abidjan, Ivory Coast. During an exploration period ending in 1977 an international joint venture group investigated the deposit and proved reserves of 670 Mt (739 million short tons) grading 36% iron. The deposit occurs at the northeast end of the Baoubly-Kiriao chain of Precambrian iron formations with associated amphibolites, pyroxenites, and gneisses of the Liberian Shield. The ore body is represented by a highly metamorphosed banded quartz-magnetite iron formation with alternating beds of iron silicates and quartz-magnetite. Amphibolite-pyroxenites and sillimanite-cordierite-garnet gneisses form hanging and footwall rocks. The iron formation has been folded into an elongated, overturned 2-shaped major drag fold with axes trending and plunging approximately northeast. Beds are vertical or dip steeply to the southeast. The ore zone has an average thickness of 130 m (427 ft) and outcrops intermittently over a distance of approximately 5.5 km (3.4 miles). Based upon detailed studies of drill cores and the results of ore dressing test work, eight stratigraphic units, identified as K- 1 to K-8, are recognizable in the iron formation. Four interbedded units are low grade silicate zones (silicate facies) while the remaining quartz-magnetite units are oxide facies, representing the important Mont Klahoyo deposit ores. Ore-bearing "K" units are subdivided further into 11 ore types, based upon their specific lithologies, iron content, and concentration characteristics. Identification of these ore types proved particularly useful to mine planning and flowsheet design. A cap of oxidized material overlies the primary quartz- magnetite iron formation, but no enrichment has occurred. It is thought that the Mont Klahoyo iron formations were deposited chemically in a volcanic environment as a siliceous iron formation with volcanism the primary source of iron and silica. Metamorphism converted the siliceous iron formation to a coarse-grained, quartz-magnetite-silicate iron formation.

Jan 1, 1983

By M. D. Banus, M. B. Bever, A. K. Jena

Measurements of the heat effects on addition of various solid phases of InSb to a solution calorimeter have confirmed the existence of a new high-pressure plzase InSbQII), which was jormed at 37 kbar and 623°K. The heats of formation of InSbQ), InSbfl), and InSb(111) have been measured and the heats of transjormation of InSb(1) to InSb(1l) and InSb(Iii) and of &apos;InSb(ll) to InSb(iiI) at atmospheric pressure and 78°K have been determined independently. Other thermodynamic properties of these phases, the phase boundary InSb(i)/InSb(ll), and the relative positions of the triple points are calculated. The pressure-Dolume term is shown to be more critical than the internal energy difference in making the phase InSbQ) less stable than InSb(II) at high pressures. Observations on partially transformed specimens suggest that the transformation of&apos; metastable InSb (III) takes place in the two steps InSb(lll) — InSbQI) and InSbQI) — InSb(l). The compound InSb can exist as several phases depending on the temperature and pressure. The phase InSb(I), which is a semiconductor having the zinc-blende structure, transforms into the phase InSb(11) at a pressure of about 23 kbar and room temperature.&apos;-3 The phase InSb(II) has the 6 tin structure,4-6 is metallic, and becomes a superconductor below 2.lok7 An orthorhombic phase of InSb has been reported to occur above a pressure of approximately 30 kbar at room temperature.&apos; This phase is also a superconductor below about 3.4k9 The phase InSb(I1) is retained at atmospheric pressure if it is quenched to 78°K under pressure,6,7 but tends to transform at higher temperatures and does so explosively above approximately 210ok,7 A value of the heat of transformation of InSb(1) to InSb(II) at 210°K and atmospheric pressure has been reported.&apos; A concurrent publication&apos;0 reports evidence for a new solid phase InSb(III), which was formed by annealing InSb above 58 1°K at 37 kbar, above 560°K at 52 kbar, and above 473°K at 65 kbar. Specimens of InSb(II1) had a superconducting transition temperature of 4.lo ± 0.1oK. X-ray diffraction patterns also indicated the presence of a new phase. In this communication, thermodynamic properties of the phases InSb(I), InSb(II), and InSb(II1) are reported and discussed. The phase boundary InSb(I)/InSb(II) and the relative positions of the triple points are calculated. 1) EXPERIMENTAL 1.1) Preparation of Specimens. Specimens of the high-pressure phases of InSb were prepared in a belt-type high-pressure chamber by a tichnique described in detail elsewhere.&apos;&apos; Charges of 0.6 to 0.8 g of Cominco semiconductor grade InSb were used. The temperatures were measured with a chromel-alumel thermocouple, the hot junction of which was within 0.5 mm of the specimen. The specimens were heated under a pressure of 37 kbar for 1 hr at 723°K (which is well above the liquidus) and quenched to room temperature. One set was annealed at 523°K and another set at 623°K for 20 to 24 hr. These annealing temperatures were chosen because 523°K was below and 623°K was above the temperature of the transformation of InSb(II) to InSb(1Tl) at 37 kbar.10 The specimens were then cooled to 125°K by passing liquid nitrogen through the jacket of the belt die before the

Jan 1, 1968

By W. A. Ver Wiebe

Under the impetus of new demands caused by the war, the oil and gas industries of Kansas established new records during the year 1942. In all, 1513 test wells were drilled, which is somewhat of a drop from the figure of 2113 for 1941. The 1513 tests yielded 800 new oil wells, 85 new gas wells, and 628 dry holes. Thus there was an increase in two categories, the gas wells and the dry holes. Considering that last year only 592 dry holes were completed out of a much larger total, the figure of 628 dry holes causes some concern among local operators. The increase in unsuccessful tests illustrates once more the fact that each year it is becoming harder to find the remaining oil pools. When the figures are broken down, it appears that western Kansas accounted for 1177 tests, of which 689 were oil wells, 33 gas wells, and 455 dry holes. The total potential daily initial production uncovered by the successful wells amounted to 753,178 bbl. of oil and 619,734,000 cu. it. of gas. The figures for new initial production indicate a substantial drop from last year&apos;s figure of 1,691,000 bbl., and the figures on gas are slightly higher. In 1941 the new gas as based on a daily potential was 508,000,-000 cu. ft. In eastern Kansas, 336 wells were drilled. Among these in were oil wells, accounting for a daily initial potential production of 16,199 bbl. The new gas wells numbered 52 and added 253,725,000 cu. ft. per day to the gas potential production of the state. The remaining tests, 173 in number, were dry. It is interesting and perhaps significant that about half (630) of the wells drilled in western Kansas were drilled by the independent operators. Among the large companies, the Cities Service Oil Co. drilled 163 wells; the Stanolind Oil and Gas Co., 52; the Skelly Oil Co., 39; the Continental Oil Co., 48; and the Shell Petroleum Co., 21 wells. In eastern Kansas the independent operators drilled 297 out of the total of 336 wells. Among the major oil companies the Cities Service Oil Co. drilled 19; the Phillips Petroleum Co. 7; and the Sinclair-Prairie Oil Co., 6 wells. The figures based on relative percentages of dry holes to successful oil or gas wells are revealing. In western Kansas almost one half of all wells drilled by the independent operators were dry holes. The major oil companies drilled approximately 547 wells in western Kansas, of which 379 were successful in finding either oil or gas. It thus appears that the major companies fared better than the independents. In eastern Kansas the major companies drilled 39 wells, of which 29 were successful in finding commercial quantities of oil or of gas. No less than 329 wildcat test holes were put down in western Kansas and 105 in eastern Kansas, or 434 in all, during 1942. Considerably more than half of these were drilled by independent operators; 223 in western and 99 in eastern Kansas. An exploratory hole 56 mile or more from production is regarded as a wildcat well in Kansas. On a percentage basis, about 80 per cent of wildcat wells were failures. In western Kansas only 20 per cent found either oil or gas. The failures were about equally distributed among the major

Jan 1, 1943

By W. A. Ver Wiebe

Under the impetus of new demands caused by the war, the oil and gas industries of Kansas established new records during the year 1942. In all, 1513 test wells were drilled, which is somewhat of a drop from the figure of 2113 for 1941. The 1513 tests yielded 800 new oil wells, 85 new gas wells, and 628 dry holes. Thus there was an increase in two categories, the gas wells and the dry holes. Considering that last year only 592 dry holes were completed out of a much larger total, the figure of 628 dry holes causes some concern among local operators. The increase in unsuccessful tests illustrates once more the fact that each year it is becoming harder to find the remaining oil pools. When the figures are broken down, it appears that western Kansas accounted for 1177 tests, of which 689 were oil wells, 33 gas wells, and 455 dry holes. The total potential daily initial production uncovered by the successful wells amounted to 753,178 bbl. of oil and 619,734,000 cu. it. of gas. The figures for new initial production indicate a substantial drop from last year&apos;s figure of 1,691,000 bbl., and the figures on gas are slightly higher. In 1941 the new gas as based on a daily potential was 508,000,-000 cu. ft. In eastern Kansas, 336 wells were drilled. Among these in were oil wells, accounting for a daily initial potential production of 16,199 bbl. The new gas wells numbered 52 and added 253,725,000 cu. ft. per day to the gas potential production of the state. The remaining tests, 173 in number, were dry. It is interesting and perhaps significant that about half (630) of the wells drilled in western Kansas were drilled by the independent operators. Among the large companies, the Cities Service Oil Co. drilled 163 wells; the Stanolind Oil and Gas Co., 52; the Skelly Oil Co., 39; the Continental Oil Co., 48; and the Shell Petroleum Co., 21 wells. In eastern Kansas the independent operators drilled 297 out of the total of 336 wells. Among the major oil companies the Cities Service Oil Co. drilled 19; the Phillips Petroleum Co. 7; and the Sinclair-Prairie Oil Co., 6 wells. The figures based on relative percentages of dry holes to successful oil or gas wells are revealing. In western Kansas almost one half of all wells drilled by the independent operators were dry holes. The major oil companies drilled approximately 547 wells in western Kansas, of which 379 were successful in finding either oil or gas. It thus appears that the major companies fared better than the independents. In eastern Kansas the major companies drilled 39 wells, of which 29 were successful in finding commercial quantities of oil or of gas. No less than 329 wildcat test holes were put down in western Kansas and 105 in eastern Kansas, or 434 in all, during 1942. Considerably more than half of these were drilled by independent operators; 223 in western and 99 in eastern Kansas. An exploratory hole 56 mile or more from production is regarded as a wildcat well in Kansas. On a percentage basis, about 80 per cent of wildcat wells were failures. In western Kansas only 20 per cent found either oil or gas. The failures were about equally distributed among the major

Jan 1, 1943

By Persifor Frazer

(Read at the Wilkes-Barre Meeting, May, 1877.) A CLASSIFICATION of natural objects is usually based either upon some fundamental and permanent attribute of the thing itself (as in the case of scientific classifications), or it embraces one or more generalizations convenient for use in ordinary life. Thus, it suffices for the statistician to, know that so many tons of fish are annually taken by our fishermen, and that they realize so many thousands of dollars, whereas to the student of natural history the anatomy, habits, and relationships of the animals are of chief interest, as settling their respective places in the scale of animate nature. Many different classifications of coals have been attempted, as one would naturally anticipate from the immense extent of the coal trade, and the different localities whence the supply was derived. The English divisions were prevalent up to the date of the publication of the last geological survey of the State, except so far as they were modified by local designations. Indeed, Rogers&apos; classifications made very little alteration in the English nomenclature, as may be seen by comparing. the tables given below. To commence with the different kinds mentioned in Ure&apos;s Dictionary of Arts, Manufactures and Mines of 1845 " 1. Cubical Coal.-Black, shining, compact, moderately hard and easily frangible. Comes out in rectangular masses, of which the

Jan 1, 1878

By Alexander Field

The hot-rolling properties of a series of high-sulfur steels are described. From a consideration of the sulfur, manganese, and zirconium contents of these steels, it is shown that zirconium reacts with the sulfur content of molten steel in accordance with the equation Zr + 2S = ZrS2. Zirconium disulfide appears in the finished state as gray-colored inclusions, similar to manganese sulfide in plastic behavior and general appearance. Zirconium completes its act of deoxidation before proceeding to combine with sulfur and indirectly increases the effective sulfur-combining power of any manganese which may be present. IN A previous paper,1 the experimental methods used and some of the results obtained in an extensive investigation of steels containing zirconium were described. The present paper considers in greater detail one of the most interesting of these effects, namely, the elimination of "red shortness" and the occurrence in steel of a compound of zirconium and sulfur. A consideration of the actual percentages of zirconium, manganese, and sulfur in numerous steels in the light of behavior during rolling has led to new conclusions of the most practical import regarding the reciprocal relationships of these elements. The microscopic examination of high-sulfur steels containing zirconium has also been productive of interesting results. Before discussing the experimental data in question, it may be stated, briefly, that the reaction between zirconium and sulfur in molten steel may he represented by the simple equation, Zr + 2S = ZrS2, and that the zirconium sulfide thus formed occurs in the finished steel in the form of gray-colored inclusions, closely resembling manganese sulfide and, like the latter, exhibiting plasticity at rolling temperatures. Molten steel containing zirconium retains such a negligibly small amount of oxygen in solution that the foregoing reaction goes to completion.

Jan 2, 1924

By Richard H. Olson

"Rarely in our technological society does the discovery of a new class of inorganic materials result in such a wide scientific interest and kaleidoscopic development of applications as has happened with the zeolite molecular sieves." That opening sentence in a landmark volume on zeolite molecular sieves by D. W. Breck (1974), is, if anything, an understatement. Zeolites were recognized as a new group of minerals in the 1750s, but it was not until 1930 that the first analysis of the crystal structure of a zeolite mineral was made. In the late 1940s research workers at Union Carbide Corp. began a program of zeolite synthesis and study which has resulted in one of the major research achievements of all time. Naturally, with the vast research and development efforts devoted to the synthetic molecular sieves, Union Carbide became concerned in the mid-1950s about its position should minable deposits of natural analogues be discovered. Zeolite minerals have diverse origins, and even a brief discussion of these is beyond the scope of this paper. The early work on zeolites was confined to igneous rock occurrences (e.g., amygdules and veins) which were formed by "space-filling;" these crystals tend to be euhedral, thereby rendering them appealing to both mineralogists and collectors. During the first year or so of Union Carbide&apos;s exploration (which began in mid-1957) attention was devoted solely to such igneous, occurrences. A landmark paper by Bramlette and Posnjak (1933) heralded the potential significance of the occurrence of zeolite minerals as alteration products of vitric ash and similar materials. In the summer of 1958, full attention was directed by Union Carbide to the search for deposits of this type in the western United States. Since then, such exploration has been continuous by both commercial firms and private parties. The future economic potential for natural zeolite deposits seems to be restricted to those of the "open-and-closed system" types as described by Sheppard (this chapter). Therefore, this and the following discussions will concentrate upon these types; the other types of zeolites in sedimentary rocks (e.g., deep-sea sediments, burial metamorphic, and hydrothermal) will be, for the most part, ignored. Despite the relative cheapness of natural zeolite deposits as compared with the cost of synthetic molecular sieves, there has been minimal development of zeolite mining in the US over the past 25 years or so. Mumpton (this chapter) discusses the present commercial utilization of natural zeolites and their future potential in detail, but perhaps the following will serve as useful background. In the early days of synthetic molecular sieve research and production, the efforts were concentrated largely upon such high-value applications as physical separation of components in a stream (based upon molecular size and geometry) and in catalysis. Due to a number of reasons (some of which are difficult for an outsider to understand), natural zeolite ores (beneficiated or not) have not made substantial inroads upon the use of the higher-priced synthetic molecular sieves for the foregoing applications, but this is not to say that such a condition will exist forever. Furthermore, in view of the many other uses which are now known, or which loom in the future, the competitive position of the natural zeolites vs. the more expensive

Jan 1, 1983

By C. Wert, D. Keefer

The results of this study indicate that sudden increases in aging temperature lead to reversion phenmena in carbon in the a, iron system. These phenomena are thought to be associated with the dissolution of carbide precipitates. Reversion is studied with respect to three variables: 1) Specimen grain size, 2) the initial amount of carbon in solution, and 3) difference between initial and final aging temperature. It is found that of these variables the initial carbon concentration has the greatest effect on reversion. THE solid solution of carbon in n iron has been the subject of numerous investigations throughout the past few years. Despite the great amount of effort which has been put forth toward understanding this system, however, there persist a number of interesting aspects of the system which are open to further research&apos; Studies Of the precipitate which forms as a result of aging a supersaturated solution of carbon in a, iron appear to be particularly interesting. The present work is an attempt to determine certain

Jan 1, 1960

By Frederick Laist

About six years ago the Anaconda Copper Mining Co. decided to investigate the possibility of extracting zinc from the ores of certain mines in the Butte district. These ores are of a complex character and contain so much iron and lead that the concentrate contains only 33 to 35 per cent. zinc. Investigations showed that while a high-grade concentrate could not be obtained by ordinary methods, such as tabling and magnetic treatment, a fair grade could be made by the Horwood process. In this method, the concentrate resulting from the flotation of all of the sulfides is given a light roast and this calcine is subjected to flotation in the presence of a large amount of sulfuric acid; the resulting concentrate contains most of the zinc and a residue contains most of the iron. The fact that the lead, copper, and silver are divided approximately equally between the zinc concentrate and the iron residue and the large consumption of acid, which ranged from 50 to 100 lb. (22 to 45 kg.) per ton of concentrates, were serious objections to this plan. The zinc recovery, moreover, was low, as a considerable percentage invariably accompanied the iron. While a profit might be made on the ores by the use of this process, it was thought that other and more promising methods might be devised. After carefully studying the field and doing some laboratory work on various processes that had been suggested, it was decided that the electrolysis of sulfate solutions was the most promising. We soon found, as have other investigators, that the only way to obtain a good zinc deposit is to have the electrolyte free from all metals more electronegative than zinc, such as copper, cadmium, lead, arsenic, antimony, etc. Arsenic and antimony are particularly injurious, causing very poor current efficiency and small yield per horsepower when present in amounts so small as almost to defy detection—1 mg. or less per liter. A pure zinc is soluble only with difficulty in sulfuric acid; an impure zinc dissolves very readily. Electrolytic zinc deposited from pure solutions is, of course, extremely pure and dissolves only about one-fiftieth

Jan 1, 1921

By William G. Schultz

Sylvite of Canada, a division of Hudson Bay Mining and Smelting Co., operates a new 8500-tpd potash mine ten miles northeast of Rocanville, Sask. This mine, employing less than 60 men in its underground maintenance, engineering, and production operations probably ranks as one of the most highly mechanized and automated mining operations in the world. Access to the flat lying potash bed is through two 16-ft-diam concrete and steel lined shafts 3300 ft deep. The backbone of the operation is two 258-ton, 1500-hp continuous mining machines capable of mining in excess of 700 tph per machine while employing extensible conveyors for haulage. This production capability is complemented by a completely automated haulage, storage, and hoisting system. Of the other unique features of this operation, the principal ones are that the mine was designed and developed by the people that are currently operating it and from the time the shafts were commissioned, the mine was completely developed, equipped, and brought to full production in less than six months.

Jan 1, 1974

By C. B. Alcock, L. I. Cheng

By the use of radiochemical methods for the study of the gas-liquid equilibria at low temperature, and for the determination of the sulfur contents of metal beads which had been equilibrated with H2S/H2 mixtures of known sulfur potential, it has been possible to obtain the liquid solubility and the free energy of solution of sulfur in liquid tin and lead at temperatures between 500°and 680°C. THE gas-liquid equilibrium method has proved in the past to be most successful in the determination of the thermodynamic behavior of dilute solutions of sulfur in liquid metals.1,2 One of the basic requirements for success with this method is that the volatility of both the metal and its lowest sulfide should be small, otherwise sulfide will be deposited at the cool end of the furnace, where it may react with the outgoing gases to form either sulfur-rich lowest sulfide or higher sulfides. The resultant value of the apparent equilibrium constant will then be lower than the correct one. This argument applies even at sulfur potentials below that in equilibrium with a separate condensed phase of the lowest sulfide at the reaction temperature, T. The mass of sulfide which is deposited at the cold end of the furnace, and hence the extent to which further reaction occurs with the outgoing gases, depends on the time taken for equilibrium to be reached between metal and gas. Since this will depend principally on the bulk of the metal phase which is used, one should clearly attempt to uie as small metal samples as possible. These considerations are important in the study of dilute solutions of sulfur dissolved in liquid tin and lead which both have moderately high vapor pressures as metals and form volatile sulfides. The limit on the size of the metal samples which may be used is set chiefly by the difficulties of analysis for very small amounts of sulfur. The oxygen or carbon dioxide combustion method, followed by iodimetric determination of the sulfur dioxide which is formed,has been found to be successful for the determination of small amounts of sulfur in copper, iron, cobalt and nickel.4 This method was unsatisfactory for sulfur dissolved in tin and lead, mainly because the sulfur dioxide was to some extent absorbed by the copious tin or lead oxide deposits which were formed on the walls of the combustion tube. Furthermore some of the sulfur was found to segregate on the surface of the beads as flaky sulfide crystals which would easily be lost in the transfer of a bead from a boat in the gas equilibration apparatus to one in the combustion apparatus. Oxidation in aqueous media to sulfate ion followed by precipitation as barium sulfate was, therefore, adopted as the analytical procedure. The gas-metal equilibrium experiments were all carried out with radioactive sulfur and thus the analysis involved the counting of barium radiosulfate. Furthermore the use of the radioisotope meant that the approach to the gas-metal equilibrium could be followed continuously by gas counting.&apos; The metal beads were held separately in glass crucibles during equilibration and were transferred from the furnace to the beaker for dissolution in nitric acid still in the crucibles, and thus the possibility of sulfur loss by detachment of the sulfide segregates was eliminated. The temperature range of this investigation was 500° to 680°C. EXPERIMENTAL APPARATUS AND METHOD The apparatus consisted of two furnaces placed in series in a gas recirculation system, Fig. 1. One furnace F1, which was vertical was used to heat the alumina crucible, A, holding six metal beads in separate glass crucibles. The beads weighed between 300 and 700 mg each. The crucible assembly was introduced and removed from the furnace mechanically under a stream of oxygen-free argon. The other furnace, F2, was horizontal and was used to heat a cobalt Co9S8 mixture, held in an alumina boat, and made with radiosulfur containing about 1/2 millicurie per g of sulphur. This mixture, which was finely powdered, was used as a source of known H2S/H2 mixtures6 for a given furnace temperature. The recirculation system also contained a gas re-circulation pump (P), an end window Geiger-Miiller counter (N)—placed downstream of F1 so as to monitor the H2S pressure in the gas leaving this furnace— a sample volume for chemical analysis of the gas phase (G), gas drying tubes (D), filling taps and other standard ancillary equipment. The gas sampling volume was principally used in the cali-

Jan 1, 1962

By D. C. Seidel, M. C. Fuerstenau, R. J. Roman

The role of surface charge in soluble salt flotation, which was developed in Part I, is extended to relate the theory to the specific phenomena of KCI-NaC1 separations. Temperature-collector solubility relationships, metal ion activation, and particle size effects are discussed. The initial paper in this series developed and presented the hypothesis that one of the mechanisms of soluble salt flotation may involve electrical attraction between the collector and mineral surface. This hypothesis was developed from a combination of experimental data and free energy calculations, and details of the logic are presented in this first paper.* The studies have indicated that KC1 has a positive surface charge and NaCl a negative charge. KC1 can therefore be floated with sulfonate ion (RSO;) or with an aqueous polar species such as the aqueous amine chloride, RNH3C1(,,). The chloride end of the RNH3C1(,,) molecular dipole is probably negative and will be attracted to the positive surface of the KC1 particles and absorb (actually probably fit into a vacant chloride site) on the mineral surface. The amine end of the collector molecule would extend into the solution phase and provide the air avid surface required for flotation. NaCl particles are floated by such collectors as aqueous molecules of fatty acid salt, RCOONa(,,), in which the positive inorganic end of the dipole is attracted to the negatively charged surface of the NaCl and, in this case, adsorb and probably fit into a vacant sodium site on the surface. The aminium cation, RNH~, should also be a collector for NaC1. For certain collectors, actual precipitates of the collector must be formed before a sufficient amount of the polar aqueous molecule is present to effect flotation. In a system of this type there is a three-way equilibrium between: Aqeous Molecular Solid Precipitate - A of the Collector (Not Dissociated) . Ionic Species (Dissociated). The controlling equilibrium is probably between the precipitated form of the reagent and the aqueous

Jan 1, 1969

By Julian M. Avery

In its dual role of pig-iron smelter and gas producer, the blast furnace is a remarkably satisfactory and efficient apparatus. Many metallurgists and engineers have pointed out, however, that since the primary function of the blast furnace is to produce pig iron at the lowest possible cost, its function as a gas producer should be subordinated to this primary purpose. During the past 10 years or more, improvements in blast-furnace technique and economy have, in fact, been directed primarily to increasing efficiency in the use of the reducing power of the gases produced by combustion of coke at the tuyeres, to reduce iron ore within the furnace. The net over-all result is a decrease in the fuel value of the top gas per unit of volume, and per ton of pig iron, which is evidently more than offset in value by the corollary saving in coke and the possibility of increased furnace capacity, for otherwise there would be no point in making such improvements. The purpose of the present paper is to suggest that, while progress has been made in this direction, there is another approach to the problem of increasing the chemical and thermal efficiency of the blast furnace in its primary role as a pig-iron smelter, which appears to offer possibilities of improvement in over-all ecorlomy of a different order of magnitude than results thus far obtained by the use of other expedients. The present argument is based in large part upon the hypothesis that the efficiency and economics of pig-iron smelting are seriously and adversely affected by the phenomenon known as "solution loss," and that the problem of solution loss call be successfully attacked by increasing the over-all pressure; i.e., the "top prcssure" under which the furnace is operated. It is indicated that pressure operation may also be expected to result in concomitant benefits, which may be summed up as generally improved operating conditions, together with a substantial saving in fuel and/or a substantial increase in furnace capacity. In a broad sense, the suggestion of pressure operation of the pig-iron blast furnace is not new, for operation under moderately increased over-all pressure was suggested as early as 1871, by no less an authority than

Jan 1, 1938

By Julian M. Avery

In its dual role of pig-iron smelter and gas producer, the blast furnace is a remarkably satisfactory and efficient apparatus. Many metallurgists and engineers have pointed out, however, that since the primary function of the blast furnace is to produce pig iron at the lowest possible cost, its function as a gas producer should be subordinated to this primary purpose. During the past 10 years or more, improvements in blast-furnace technique and economy have, in fact, been directed primarily to increasing efficiency in the use of the reducing power of the gases produced by combustion of coke at the tuyeres, to reduce iron ore within the furnace. The net over-all result is a decrease in the fuel value of the top gas per unit of volume, and per ton of pig iron, which is evidently more than offset in value by the corollary saving in coke and the possibility of increased furnace capacity, for otherwise there would be no point in making such improvements. The purpose of the present paper is to suggest that, while progress has been made in this direction, there is another approach to the problem of increasing the chemical and thermal efficiency of the blast furnace in its primary role as a pig-iron smelter, which appears to offer possibilities of improvement in over-all ecorlomy of a different order of magnitude than results thus far obtained by the use of other expedients. The present argument is based in large part upon the hypothesis that the efficiency and economics of pig-iron smelting are seriously and adversely affected by the phenomenon known as "solution loss," and that the problem of solution loss call be successfully attacked by increasing the over-all pressure; i.e., the "top prcssure" under which the furnace is operated. It is indicated that pressure operation may also be expected to result in concomitant benefits, which may be summed up as generally improved operating conditions, together with a substantial saving in fuel and/or a substantial increase in furnace capacity. In a broad sense, the suggestion of pressure operation of the pig-iron blast furnace is not new, for operation under moderately increased over-all pressure was suggested as early as 1871, by no less an authority than

Jan 1, 1938

By Louis Bender

AFTER investigating the work of coal-dust fired reverberatories of the Canadian Copper Co., at Copper Cliff, Ontario, the management of the Washoe Reduction Works decided to experiment with and ascertain the advantages of using coal dust as a fuel in their reverberatories. Consequently, during the month of June, 1914, reverberatory furnace No. 8 was changed in order to use powdered coal as a fuel. The results obtained by this method of firing are gratifying and show a decided saving in cost of smelting as compared to grate firing with lump coal. The furnace, as remodeled; is 124 ft. long by 21 ft. wide, and varies in height from 8 ft. 6 in. at the back end to 5 ft. 7 in. at the skimming end. The general construction of the furnace is similar to that of the other furnaces at this plant. There are no side doors to this furnace, as it was thought that with the present arrangement for feeding no "fettling" or "claying" would be required. The interior of the furnace can be inspected through the burner port holes, after shutting off the burners and giving a few seconds&apos; time for the gases inside the furnace to clear away. The charging is done on either side of the furnace from longitudinal hoppers, extending a distance of 74 ft. from the back end of the furnace. Leading from the hoppers into the furnace are 6-in. pipes, spaced 194 in. apart, through which the charge is intermittently dropped. The charge is kept well above the slag line at all times; in this way the side walls are protected and no fettling is needed on this portion of the furnace. The remainder of the furnace requires fettling. After operating for three months, we found that the bricks were eaten into along each side wall from the skimming door back to the point where the charge had been dropped. The depth of this cutting away was 8 in. close to the front end and gradually tapered to zero at a distance of 50 ft., and was greatest on the side of the furnace having the larger flue connection. Hoppers will be put in for the entire length of furnace, from which fettling material will be dropped, to prevent this cutting.

Jan 1, 1915