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By C. N. Schuette

THE producers of this liquid metal call it quicksilver, while the consumer generally refers to it as mercury. It is one of he seven metals that were known to the ancients. These seven were gold, silver, iron, copper, quicksilver, lead, and tin. Other metals were sometimes accidentally alloyed with some of these, but it was not until 1490 that antimony, for example, was discovered and identified as a separate metal. It is not surprising that quicksilver should have been known in ancient or even in prehistoric times, as globules of the native metal often occur in the outcrops of the ore. Furthermore, the first man to build a fire on an outcropping of quicksilver ore would probably have found globules of quicksilver in the cold ashes of his fire after it burned out. The inability to pick up the globules with the fingers would excite interest and an attempt to gather it in shells or gourds to be exhibited and traded. The ore of quicksilver is the red sulfide, cinnabar, which has been mined and used as the pigment vermilion since before the beginning of written history. In recorded history, quicksilver is first mentioned in documents by Aristotle, 384-322 B.C. Theophrastus, in 315 B.C., credited the Athenian, Callias, with the invention of methods to beneficiate cinnabar in 415 B.C. In China also there are records antedating Christ which mention both vermilion paint and the fluid metal. From these early records, it seems certain that not only was cinnabar used as a pigment in those days but also that the metal was reduced from the ore and was used for amalgamation, for gilding, and for medicinal purposes. Quicksilver mining and metal-

Jan 1, 1953

By L. Moussoulos

Pyrite concentrates produced at the Olympias mines, Northern Greece, show an unusually high gold and silver content (16-20 and 25-40 ppm respectively), associated with the presence of arsenopyrite; their high As content (5-8%) has hindered their utilization so far. In the present paper a simple and environmentally safe method that permits their complete utilization for the production of SO2 gas, As203, and the recovery of Au and Ag is described. According to this method, the pyrites are subjected to a single-stage oxidizing roasting in a fluid bed reactor. The precious metals, and approximately 45% of the contained As, remain with the cinders, while the rest of the As is removed with the SO2 - bearing gases and can be recovered by suitable treatment. The gases, after further cleaning, can be utilized for the production of sulfuric acid.

Jan 1, 1984

By W. E. Bergman, P. G. Carpenter, H. B. Fisher

The conditions under which barium carbonate can be used to remove sulfates from drilling muds are limited The amount of sulfate remaining in solution in the system after treatment with barium carbonate is shown to be a function of the concentration of the carbonate and barium ions and the concentration of other electrolytes. Barium hydroxide may advantageously replace barium carbonate when the contamination is not entirely due to anhydrite (calcium in the system is then stoichiometrically less than sulfate) or when the carbonate concentration is high. The effect of substances such as quebracho, phosphates, and chromates, which form complexes or precipitates with barium, is discussed. INTRODUCTION As the complexity of the operations in drilling for oil has increased, more attention has of necessity been directed to the problems pertaining to the maintenance of good drilling mud properties. As a result, chemical treatment of muds has become an important factor in recent years. Some of these treatments have been designed to eliminate the deleterious effects of contaminants in aqueous mud systems by precipitation or other means. The most common of substances encountered during drilling include sodium chloride, cement, and calcium sulfate while various other contaminants: usually in small amounts, may be introduced from the water, clays, and other materials used in preparation of the mud. In certain cases, for example where continued salt-water flow is encountered or massive anhydrite is drilled, special muds may be used so that the physical properties of the mud will remain satisfactory for drilling. In other cases, it is desirable to remove the contaminants so that soluble electrolytes in the system are maintained at low values. For sulfate contamination, the conlmon practice in the field is to add barium carbonate to precipitate the sulfate as barium sulfate Ordinarily such a procedure gives satisfactory results. There have been important instances, however, where addition of barium carbonate was not effective in removal of soluble sulfates from drilling muds. and it is to these cases that the present paper is directed. While it is generally known that barium carbonate is not always effective in removing soluble sulfates from drilling muds, certain inconsistencies appear in the literature as to the limitations of its use, and little explanation for the limitations are given. Varnell and Kimbrel state that "the treatment (with barium carbonate for removal of sulfate) is simple and consists in maintaining a pH of 9 with caustic soda and quebracho." They caution that concentrations of quebracho greater than 1 lb./bbl. may inhibit the reaction. In another publication', a pH of 10.5 is considered "the maximum desirable," and the indication is that as much as 2.5 lb. quebracho per barrel may be present in the particular mud under discussion. Lancaster and Mitchell5 state that appreciable amounts of phosphates in the mud will inhibit the reaction with barium carbonate and that the phosphate treatment should be discontinued at least 24 hours before addition of the carbonate. Experimental work was initiated to ascertain the factors involved in using barium carbonate for the removal of sulfate contamination in drilling muds. While the experimental data herein reported are limited, they focus attention on the pertinent factors which must be considered for successful treatment. These factors are discussed from a practical and a theoretical view, the latter being supported by equilibrium data found in the literature. Further, it will be appreciated that the factors involved in this specific study will be closely analogous to those in certain of the other chemical treatments which involve a precipitation of the soluble contaminant. A thorough comprehension of these factors should result in a more fruitful application of this type of chemical reaction to the treatment of drilling muds. EXPERIMENTAL A. Reagents Two muds were used during this investigation. For one series of tests, bentonite suspensions were prepared by dilution of a stock suspension containing 8 per cent by weight of bentonite (Aquagel). For another series, a 6.4 per cent ben-tonitic mud weighted to 9.7 lb./gal. with barium sulfate (Mag-cobar) was used. Distilled water was used in all preparations. The quebracho (72% tannin extract) was obtained from the Thompson-Hayward Co. of Tulsa and contained 11.4 per cent moisture (105 C.). All other materials were reagent grade, and concentrations were corrected for water of crystallization, if any. All concentrations are expressed in pounds per barrel (42 gallons). B. Technique The systems — either mud or water — were contaminated with either sodium or calcium sulfate after treatment with the desired amounts of sodium hydroxide and quebracbo. For treatments with barium carbonate an approximately 3-fold excess (5 lb./bbl.) was used over that computed to be required to precipitate all the sulfate as barium sulfate. Barium hydroxide was used in concentrations of 2 lb./bbl. — about

Jan 1, 1949

By P. G. Carpenter, H. B. Fisher, W. E. Bergman

The conditions under which barium carbonate can be used to remove sulfates from drilling muds are limited The amount of sulfate remaining in solution in the system after treatment with barium carbonate is shown to be a function of the concentration of the carbonate and barium ions and the concentration of other electrolytes. Barium hydroxide may advantageously replace barium carbonate when the contamination is not entirely due to anhydrite (calcium in the system is then stoichiometrically less than sulfate) or when the carbonate concentration is high. The effect of substances such as quebracho, phosphates, and chromates, which form complexes or precipitates with barium, is discussed. INTRODUCTION As the complexity of the operations in drilling for oil has increased, more attention has of necessity been directed to the problems pertaining to the maintenance of good drilling mud properties. As a result, chemical treatment of muds has become an important factor in recent years. Some of these treatments have been designed to eliminate the deleterious effects of contaminants in aqueous mud systems by precipitation or other means. The most common of substances encountered during drilling include sodium chloride, cement, and calcium sulfate while various other contaminants: usually in small amounts, may be introduced from the water, clays, and other materials used in preparation of the mud. In certain cases, for example where continued salt-water flow is encountered or massive anhydrite is drilled, special muds may be used so that the physical properties of the mud will remain satisfactory for drilling. In other cases, it is desirable to remove the contaminants so that soluble electrolytes in the system are maintained at low values. For sulfate contamination, the conlmon practice in the field is to add barium carbonate to precipitate the sulfate as barium sulfate Ordinarily such a procedure gives satisfactory results. There have been important instances, however, where addition of barium carbonate was not effective in removal of soluble sulfates from drilling muds. and it is to these cases that the present paper is directed. While it is generally known that barium carbonate is not always effective in removing soluble sulfates from drilling muds, certain inconsistencies appear in the literature as to the limitations of its use, and little explanation for the limitations are given. Varnell and Kimbrel state that "the treatment (with barium carbonate for removal of sulfate) is simple and consists in maintaining a pH of 9 with caustic soda and quebracho." They caution that concentrations of quebracho greater than 1 lb./bbl. may inhibit the reaction. In another publication', a pH of 10.5 is considered "the maximum desirable," and the indication is that as much as 2.5 lb. quebracho per barrel may be present in the particular mud under discussion. Lancaster and Mitchell5 state that appreciable amounts of phosphates in the mud will inhibit the reaction with barium carbonate and that the phosphate treatment should be discontinued at least 24 hours before addition of the carbonate. Experimental work was initiated to ascertain the factors involved in using barium carbonate for the removal of sulfate contamination in drilling muds. While the experimental data herein reported are limited, they focus attention on the pertinent factors which must be considered for successful treatment. These factors are discussed from a practical and a theoretical view, the latter being supported by equilibrium data found in the literature. Further, it will be appreciated that the factors involved in this specific study will be closely analogous to those in certain of the other chemical treatments which involve a precipitation of the soluble contaminant. A thorough comprehension of these factors should result in a more fruitful application of this type of chemical reaction to the treatment of drilling muds. EXPERIMENTAL A. Reagents Two muds were used during this investigation. For one series of tests, bentonite suspensions were prepared by dilution of a stock suspension containing 8 per cent by weight of bentonite (Aquagel). For another series, a 6.4 per cent ben-tonitic mud weighted to 9.7 lb./gal. with barium sulfate (Mag-cobar) was used. Distilled water was used in all preparations. The quebracho (72% tannin extract) was obtained from the Thompson-Hayward Co. of Tulsa and contained 11.4 per cent moisture (105 C.). All other materials were reagent grade, and concentrations were corrected for water of crystallization, if any. All concentrations are expressed in pounds per barrel (42 gallons). B. Technique The systems — either mud or water — were contaminated with either sodium or calcium sulfate after treatment with the desired amounts of sodium hydroxide and quebracbo. For treatments with barium carbonate an approximately 3-fold excess (5 lb./bbl.) was used over that computed to be required to precipitate all the sulfate as barium sulfate. Barium hydroxide was used in concentrations of 2 lb./bbl. — about

Jan 1, 1949

By J. H. Swisher, E. O. Fuchs

Rate equations were derived to describe the kinetics of internal oxidation of cylinders and spheres. The derived equations for cylinders were checked experimentally by means of sub scale thickness and electrical conductivity measurements on Cu-Cr alloy wires. The properties of the internally oxidized samples were examined with conductivity applications in mind. It was possible to produce uniform dispersions of Cr2O3 in copper with an initial chromium content as high as 3 wt pct. While electrical conductivities only a few pct less than that of OFHC copper were obtained, the Cr2Os particle size and spacing were too large for effective dispersion hardening. T.HE process of internal oxidation has been used widely in basic studies of the permeability of gases in metals. In a review article, Rapp1 has discussed the principles of internal oxidation in considerable detail. From a technological standpoint, internal oxidation is often considered undesirable, since it is a means by which inclusions can be introduced into an otherwise clean material. Another important aspect of internal oxidation is its use as a means of dispersion hardening a material. Broutman and Krock2 discuss this and other methods for making dispersion hardened alloys. The only internally oxidized material known to the authors which is commercially available is a Cu-BeO alloy.3'4 This alloy is made from Cu-Be alloy powder, using a so-called Rhines pack. It has a tensile strength of 80,000 psi and retains its strength at relatively high temperatures. The objectives of the present study were to derive rate equations for the internal oxidation of cylinders and spheres, to check the derived equations for cylinders experimentally, and to examine the structure and properties of internally oxidized Cu-Cr alloys. The Cu-Cr system was chosen for this study because uniform dispersions are obtainable at high alloy contents, which is a desirable characteristic in dispersion hardened materials. RATE EQUATIONS FOR VARIOUS GEOMETRIES A number of authors5--9 have derived equations to describe internal oxidation kinetics. These derivations differ somewhat in mathematical assumptions and approximations, and all except one of the derivations deal exclusively with the internal oxidation of plates. The exception is a brief treatment of cylindrical and spherical geometries given by Meijering and Druy-vesteyn9 as a part of a comprehensive paper on the general subject of internal oxidation. These authors did not obtain rate data to check their derivations, although they did show that the hardness profile across an internally oxidized sample is directly related to the rate of interface movement. For cylindrical and spherical geometries, a quasi-steady-state approximation is needed to circumvent mathematical complications in obtaining a solution to the basic differential equations. In using this approximation, we consider the concentration gradient of dissolved oxygen in the internally oxidized zone or sub-scale to be the same as the gradient which would be present if there were no movement of the subscale interface. The steady-state approximation introduces an error of about 1 pct in computing the rate of internal oxidation of an Fe-1.0 pct Mn alloy plate, if the present method is compared to the more exact method of Wagner.7'10 The details of the derivations of the rate equations for cylinders and spheres are given in the Appendix, and only the results of these derivations are given below. The final equations obtained by Meijering and Druyvesteyn9 can be shown to be equivalent to our Eqs. [1] and [2], although the two approaches are somewhat different. Cylindrical Geometry. [2] where r1 is the outer radius of the cylinder or sphere, cm, r2 is the radius of the unreacted core, cm, see Fig. l(a), D is the diffusion coefficient of oxygen in copper, cm2 per sec, %O is the concentration of dissolved oxygen at the surface of the specimen, wt pct, %Cr is the initial chromium concentration in the alloy, wt pct, and t is the reaction time, sec. Plate Geometry. The analogous rate equation for a plate has been derived previously for internal oxidation of Fe-Al alloys.8'11 For Cu-Cr alloys, we may write the same equation as follows: [3] where r1 is the half-thickness of the plate, cm, and r2 is the distance from the mid-plane to the subscale intherate is An analysis of Eqs. [1], [2], and [3] shows that for a plate the rate is completely parabolic. The initial

Jan 1, 1970

By W. B. Gogarty

The reported decreases in water mobility do not seem unusual in view of non-Newtonian fluid properties. Shear stress vs shear rate diagrams have been reported for other solutions of water-soluble polymers. Some of these polymers are similar to the type mentioned by the author. Generally, the shear stress-shear rate is a non-linear function for these solutions. Data for plotting apparent viscosity vs shear rate can be obtained from this function. Apparent viscosity is defined as the ratio of shear stress to shear rate at a given shear rate. When plotted, the apparent viscosity decreases with increasing shear rate. This behavior is typical of a pseudoplastic fluid. For some water-soluble polymer solutions, the apparent viscosity decreases more than 50 times while the shear rate increases 1,000 times. Thus, viscosity of a pseudoplastic fluid only has meaning at a specified shear rate. Results of Fig. 1 could be explained in these terms. Viscosities measured in the Ostwald viscometer represent values at a given shear rate. Some average shear rate is affecting the polymer solutions while flowing through the core. This average value fixes the apparent viscosity as long as the flow rate remains constant. Viscosities measured by the two methods will be equal if shear rates are the same. The results indicate that shear rate in the core is lower (higher apparent viscosity) than in the viscometer. In the paper by Johnson, Bossler and Naumann, the relative permeability is independent of viscosity ratio. Thus, the relative permeability with respect to water flow at residual oil should be independent of the flowing phase viscosity. Polymer solutions will appear as Newtonian fluids The discussion emphasizes the nature of the "resistance factor effect" as discussed in the paper. Repeated anomalies arising in hundreds of experiments led us to the conclusion that non-Newtonian flow is not the only factor. Several of the key anomalies are as follows: 1. Measured viscosities over a range of shear rates from <1 sec-&apos; to 1,000 sec-&apos; do not account for but a minor fraction of the R observed in cores when compared in similar shear-rate ranges. 2. The slope of R vs flow rates in cores is always different from that expected from viscometer shear-rate measurements as shown in Fig. 2. in a core, the level of viscosity being fixed at a given flow rate. With these conditions, the definition of resistance factor R by Eq. 2 is simplified to Since , is constant with rate, R becomes a measure of the apparent viscosity in a core at a given flow rate. Variation in flow rate could easily account for the changes of R shown in Fig. 5. Also, this points to the fallacy of assuming R to be a unique parameter. The constant resistance factors at different flooding velocities appear to be in disagreement with the above discussion. The author furnishes Fig. 2 to support his arguments. As shown, the resistance factors remained substantially constant in the two cores over a considerable range of flooding velocities. However, in the 73-md core, the factor increases at lower rates. This behavior agrees with known characteristics of some pseudoplastic material. These materials act both as Newtonian and as non-Newtonian fluids in different regions of shear rate. Some exhibit first Newtonian, then non-Newtonian, finally, Newtonian character. Others are first non-Newtonian and then Newtonian. This latter type would explain the results with the 73-md core. The Fann-instrument results are not significant since shear rates in the core may be much different than with the viscometer. The higher resistance factor at high rates in the 150-md core is more difficult to explain. The greater resistance at increased flow rates could be attributed to what might be termed temporary bridging. As envisioned, changes in polymer configuration occur at the higher energy associated with the increased flow rate. These changes could cause less effective passage of polymer through the core. Correspondingly, increases in pressure drop will occur. These will be interpreted as higher resistance factors. 3. Most polymer solutions are non-Newtonian and many are more shear-rate sensitive than the polymers in question, yet only a very few polymers demonstrate useful R values. Gogarty&apos;s assumption that viscosities in cores and vis-cometers will be the same if measured at the same shear rate is only valid if non-Newtonian rheology is the only parameter. The experimental evidence does not validate this assumption. The anomalies observed in the equilibrium displacement experiment shown in Fig. 5 are not explained on the basis of varying flow rates since the rates were held constant. M

Jan 1, 1965

By F. R. S., B. Hopkinson, R. Hadfield

A short time ago Professor Stoughton askes the writer if he would present a paper for the Feburary meeting of our Institute.

Jan 1, 1915

By Erwin S. Sperry

It is a tradition in the brass industry that bismuth is ail injurious element in brass, even more deleterious than antimony; but such a belief has lacked verification. The occasional presence of bismuth in commercial copper (although less frequent than was formerly supposed) led the author to investigate this tradition. The f&apos;ollowing experiments mere conducted in the same man-

Jan 1, 1899

By Charles V. Riley

While the late 1960&apos;s are known as the years of the public recognition of impending environmental crises, the 1970&apos;s will be known as the decade of public concern for improving the quality of that environment. One of the major environmental concerns is the temporary disturbance resulting from coal surface or open cast mining. Increasing energy demands in the U.S., a doubling of electrical power consumption each decade during the present century and the projected needs for the remainder of the century are indications that coal surface mining as a major extractive industry will continue. Coal and lignite, prime energy resources and extremely abundant in these United States, in the face of seemingly limited gas, oil and uranium reserves, are both destined for expanded future use. Presently some extremely serious technological and environmental problems are associated with the development and use of nuclear power. It is true that the extraction and use of coal as an energy fuel poses disruptive problems for the environment, but the solutions to many of the problems are known or can he solved within a reasonable time framework Certainly our national well-being and continued survival as a free nation within the world community automatically dictate the continued use of the coal resource for energy. Concurrently, those engaged in coal surface mining, with the temporary disturbance of the land and water resources, must also realistically conclude that public concern for maintaining and improving the quality of the environment will not diminish. Although as ecological, economic, social and aesthetic elements of cost-benefits and human desires are more adequately understood, a more rational and reasonable public and governmental attitude hopefully will result.

Jan 3, 1973

By Nico Van Wingen

Experiments performed with distilled water, unconsolidated sand and dead oil for the purpose of determining the influence of oil flow on the water content of sands were described. While results found are not necessarily, therefore, identical with those that would be obtained under natural petroleum reservoir conditions, the following conclusions were drawn. 1. When oil under constant head is flowed through an unconsolidated sand, the amount of water retained in the core is inversely proportional to the specific permeability of the core. This corroborates the view that the degree to which oil displaces water out of the pore space is limited by the size of the pores. 2. For the range investigated, the displacing action of a more viscous oil of higher specific gravity was found to be the same as a less viscous oil, or lower specific gravity. 3. The amount of interstitial water retained in the sand bears an inverse relationship to the pressure head of the displacing liquid. 4. The degree of retained water saturation of the sand appears to approach 100 per cent as the specific permeability approaches zero. 5. For the higher values of specific permeability and for the pressure range investigated the remaining amount of water in the sand occupies approximately 10 per cent of the pore space. This, together with the fact that the limiting oil velocity curve approaches approximately 10 per cent water saturation as an asymptote, indicates that beyond this point removal of water is achieved only by a stripping of the grains requiring considerable pressure drops across the sands; or by a balancing of the molecular forces. 6. As the water saturation of the sand exceeds approximately 15 per cent of the pore volume, the permeability of the sand to oil decreases rapidly. 7. Sands with water saturations as high as 40 per cent were found to produce 100 per cent oil.

Jan 1, 1939

By Nico Van Wingen

Experiments performed with distilled water, unconsolidated sand and dead oil for the purpose of determining the influence of oil flow on the water content of sands were described. While results found are not necessarily, therefore, identical with those that would be obtained under natural petroleum reservoir conditions, the following conclusions were drawn. 1. When oil under constant head is flowed through an unconsolidated sand, the amount of water retained in the core is inversely proportional to the specific permeability of the core. This corroborates the view that the degree to which oil displaces water out of the pore space is limited by the size of the pores. 2. For the range investigated, the displacing action of a more viscous oil of higher specific gravity was found to be the same as a less viscous oil, or lower specific gravity. 3. The amount of interstitial water retained in the sand bears an inverse relationship to the pressure head of the displacing liquid. 4. The degree of retained water saturation of the sand appears to approach 100 per cent as the specific permeability approaches zero. 5. For the higher values of specific permeability and for the pressure range investigated the remaining amount of water in the sand occupies approximately 10 per cent of the pore space. This, together with the fact that the limiting oil velocity curve approaches approximately 10 per cent water saturation as an asymptote, indicates that beyond this point removal of water is achieved only by a stripping of the grains requiring considerable pressure drops across the sands; or by a balancing of the molecular forces. 6. As the water saturation of the sand exceeds approximately 15 per cent of the pore volume, the permeability of the sand to oil decreases rapidly. 7. Sands with water saturations as high as 40 per cent were found to produce 100 per cent oil.

Jan 1, 1939

By S. M. Runke, R. G. Meara, O&apos

The Bureau of Mines has been charged by Congress to investigate processes for the production of alumina from low-grade bauxite, alunite, and clay. As one part of the program, an investigation of the application of ore-dressing methods to improve the grade of high-silica bauxite is in progress at the Mississippi Valley Experiment Station at Rolla, Mo. This paper summarizes data obtained so far and presents detailcd results of tests on four typical samples. Mineralogy of Batjxite The name bauxite originally was used to designate the dihydrous aluminum oxide (A1203.2HzO). The designation has been retained, although the existence of a specific mineral of such composition has been disproved. The term is now applied to ores of aluminum consisting of various mixtures of the minerals gibbsite (AlzOa.3H20), diaspore (A120a.H20), and boehmite (Alr-03.H20). The predominant hydrous aluminum oxide in most American bauxite, however, is gibbsite. In some instances bauxite may be amorphous mixtures of the hydrous aluminum oxides that approximate the composition of dihydrous aluminum oxide (A1203.2Hz0). The proposed name for this material is cliachite. Gibbsite and boehmite, the trihydrate and monohydrate, are soluble in a solution of sodium hydroxide at elevated temperature and pressure, whereas diaspore is practically insoluble. The solubility of these two minerals is the basis of the Bayer process of alumina extraction. All bauxites contain certain impurities, the commonest of which, in the order of their importance, are: silica, principally as a constituent of kaolinite, and to a lesser extent as quartz; iron, as hematite, limonite, and siderite; and titanium, as ilmenite, rutile and leucoxene. Minor impurities are zircon, cobalt and nickel. Bauxite is produced commercially in Arkansas, Alabama, Mississippi, Georgia and Tennessee, but the most important deposits in the United States are in Arkansas, in the vicinity of Little Rock. History of Batjxite Beneficiatjon The literature on bauxite beneficiation is limited, but the reports of Gandrud and DeVaneyl and Clemmer, Clemmons, and Stacy2 show the possibilities of flotation as a means of beneficiating bauxite. Their work has also developed reagent combinations that are satisfactory for flotation of gibbsite.

Jan 1, 1944

By Edward Walsh

In the early history of the production of metallic iron from the native oxides or ores, success attended the labors of the workman according to the care he devoted to his work, and according to the degree of skill he possessed in furnishing the required amounts of fuel and ores to be acted upon by the blast propelled by the bellows, trompe, or wooden tub, and delivered into the hearths of the Persian, bloomery, or Catalan forges. The same skill may also have been of avail in the use of the lower forms of the ".Stück," "Blue,"or" Wolf"

Jan 1, 1887

By D. M. S. Bhatia, Richard D. Hagni

Five sulfide minerals from the Magmont mine, southeast Missouri were sampled for 31 trace elements in over 300 samples by laser microprobe spectrographic analysis of polished sections. The concentration of several trace elements shows a pattern of progressive variation with depth (space) and variation with different paragenetic stages (time) of each mineral. Factor analysis of the geochemical data shows sympathetic correlation both in space and in time of Bi, Cd, Ge, and Sn in galena and sphalerite, and Ni and Co in sphalerite and marcasite.

Jan 1, 1981

By E. K. C. Williams, Nathaniel Arbiter

INTRODUCTION The surface processes involved in preparing ores for flotation and for operations depending on their flocculation/dispersion characteristics * vary widely in agitation dependence. Most of the reagents used for these purposes are added to grinding circuits, pump sumps, launders, or directly to flotation cells with the turbulent flow conditions usually adequate both for mixing reagents and for surface reactions without special conditioners. However, some reagent systems do require specific control of agitation intensities and reaction times, the more important of these being the following: 1. Activation of ZnS with CuSO4. With the usual conditions pH about 10, with collector added with the CuSO4, Cu 2+ is almost completely precipitated as basic compounds and as collector salt. As a result the levels of reagent in solution are extremely low which probably accounts for the need for separate conditioning. The agitation intensities are at about the 0.01 HP/ton level.** 2. Flocculation with natural or synthetic polymers. In this case the agitation problem is two-fold; first, to insure adequate initial mixing of the viscous stock solution of the

Jan 1, 1980

By W. J. Babyak, J. M. Sheehan, H. W. Paxton

THE- solubility of hydrogen and deuterium in solid niobium up to I-atm pressure has been established bv a number of workers.1-5 X-ray examination at room temperature of specimens reacted in hydrogen at high temperatures from 300° to 1000°C shows the presence of two phases—a bcc phase (a) based on the niobium lattice and with an u0, increasing from 3.30A for Nb to 3.32Afor NbHo.L, and an orthorhombic phase6n = 4.84A, h=4.90A, c =

Jan 1, 1960

By C. Norman Bowers, Blaine B. Wescott

MARKED improvement in the serviceability of sucker rods has been effected in the last two years, partly because of the insistent necessity for greater economy in the operating costs of crude oil production growing out of the general industrial depression and partly because many of the recently developed fields have imposed more severe operating conditions upon both surface and underground equipment. The latter is particularly true of Kansas, where practically all of the oil produced. is associated with damaging amounts of hydrogen sulfide brine and where the method of establishing potential production demands equipment capable of being operated at maximum capacity without interruptions. The decline of flush production in the Oklahoma City field created new problems in deep-well pumping on a scale heretofore unequaled and the increased proportion of water it has been necessary to produce in the fields of the Greater Seminole area presented conditions that were acutely in need of betterment. The problem in the latter fields was complicated by the shift towards sulfide characteristics, which accompanied water encroachment, and it is probably true that nowhere, at the present time, are pump¬ing conditions generally as severe as in this territory. The Mid-Continent district, therefore, has become the proving ground for the numerous materials that have been proposed for sucker-rod fabrication. The information that ultimately will be obtained from an unprecedented amount of field experimentation will pay ample dividends when the decline of East Texas increases the demand for the vast reserves of sour crude in West Texas. It is a rare occurrence in industry that the use of such a simple piece of equipment as a sucker rod presents so complicated a problem for solution. As proof of this, it is only necessary to consider the numerous types of sucker rods on .the market at the present time and contrast this condition with that of less than four years ago, when it was the common aim of manufacturers to develop a single sucker rod for all conditions of

Jan 1, 1935

By Keith Leonard 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 [ ] 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 Earl R. Johnson

Ore broken at the mine or quarry face generally is loaded by power shovels into large trucks or rail cars and hauled to a primary crushing plant where it is reduced to a more workable size for ease in handling. The primary crushing plant is customarily located as close as possible to the center of gravity of the ore body and the projected limits of the mine pit to minimize the cost of hauling and to increase safety from flying rock as a result of blasting operations. A belt conveyor is used to transport the crushed product to a nearby ore treatment plant or, should this plant be located some distance away, the ore is loaded directly into cars and hauled by rail. Between trips the crusher product is accumulated in bins or stock piles. In all open pit mining and quarrying operations, the power shovel, the transportation equipment, and the primary crushing plant should work as a team, complementing each other. When establishing the design and selecting the equipment for these closely integrated operations, capital and operating costs for each unit operation must be weighed to achieve an optimum balance. Rising labor costs have given impetus to the universal trend toward greater efficiency, higher speed and larger equipment, and higher degrees of automatic control. The result is that power shovels have increased in size, haulage trucks are larger and faster, and only coarse crushers with feed openings adequate to receive run-of-mine lumps of ore with a minimum of secondary blasting are selected for new installations. These coarse crushers also have large through-put capacities, even when adjusted to produce a 6- to 10-in. size of product, thus making it possible to use a single stage of coarse crushing at the average mine. The use of a single crusher results in a compact crushing plant layout consisting of a dumping pocket for receiving loads of run-of-mine ore, a coarse crusher followed by a surge chamber for the crushed product, and a feeder to withdraw the ore at a uniform rate to deposit it on a belt conveyor. A

Jan 1, 1968

By Will H. Coghill, Fred D. DeVaney, R. G. O’Meara

The size of ball mills in the ore-dressing industry has increased from about 4 ft. in each dimension to 10.5 ft. in diameter by 8 ft. in length. In the cement industry they are as long as 45 ft. Plainly the trend has been toward larger mills. The common belief is that the big mills economize in floor space and first cost, but the advantage with respect to friction has not been clearly defined. In the ball-mill studies at Rolla, Mo., laboratory mills as small as 2 by 2 ft. have been found as efficient in terms of the amount of grinding per unit of net power as mills 6 by 4 or 6 by 12 ft. Therefore, if supremacy can be claimed for the big mills, advantage must come from other sources. The advantage to be considered here is reduced loss by friction or dead load. In the study to determine whether big mills have relatively less loss by friction the commercial catalogs were used for fundamental figures. The dimensions and weights of Table 1 are taken from the catalogs (the last line gives data on a Rolla laboratory mill). The net power—that is, the power expended within the mill for grinding—is calculated by a new formula.&apos; The assumed speeds are each at 70 per cent of their theoretical critical speeds, and the mills are loaded to the center with balls. In other words, they are assumed to be working under analogous conditions and are set for good grinding. In the last column the ratio B: A shows that the larger commercial mills are lighter per unit of net power than the smaller mills, and more of the motor output should therefore go into grinding. The laboratory mill seems to have some advantage over the larger mills; it would be expected to be light because it has no liners.

Jan 1, 1935