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By Georg Masing

Jan 1, 1933

Jan 1, 1932

By Allen J. Johnson

It is probable that the word "anthracite" was derived from the Greek preposition an, and the Greek word for Thrace, meaning, in combination, "toward or near Thrace." Aristotle, Theophrastus, Strabo and Pliny all mention Thrace, or Samothrace, in treatises upon stones and stone coals dating back to about 371 B.C. In 1769 Obadiah Gore, a blacksmith of Wilkes-Barre, successfully burned anthracite in his forge, the first of millions of consumers of Pennsylvania anthracite. The Anthracite Region While anthracite is found in widely scattered locations throughout the world, 99 per cent of the total production of the United States origintitles within an area of 3300 square miles in castern Pennsylvania, less than 500 square miles of which arc underlain by workable coal beds. Eminent authorities such as the United States Geological Survey agree that this Pennsylvania anthracite is the only true anthracite east of the Rocky Mountains. There is some graphitic anthracite in Rhode Island but it is not suitable for combustion; and coals from such states as Virginia and Arkansas, frequently sold as anthracite, are in reality semi-

Jan 1, 1934

By L. W. Kempf, R. S. Archer

The binary aluminum-silicon alloys have certain characteristic advantages which are now well known, and these alloys have come into considerable use during the past several years.' Their field of application has been limited to a certain extent, however, by their low yield point and hardness, low endurance limit, and relatively poor machining characteristics. These properties are improved by the addition of copper, and the ternary aluminum-silicon-copper alloys constitute an important class. The addition of copper decreases the corrosion resistance of the aluminum-silicon alloys and increases specific gravity. Magnesium is a hardening addition which seems to have relatively little effect on corrosion resistance, and which, of course, reduces specific gravity. The object of the work described in this paper was the development of alloys and heat treatments for the production of sand castings and permanent-mold castings having substantially all the advantages of the binary aluminum-silicon alloys together with mechanical properties improved to a degree permitting wider application. Constitution of Alloys Magnesium and silicon combine in aluminum alloys as the compound Mg2Si, which forms a binary system with aluminum. In alloys containing an excess of silicon over that required to form the compound, solidification ends with the freezing at 1022' F. (550' C.) of a ternary eutectic of aluminum, Mg²Si, and silicon. Judging from the horizontal projection of the liquidus surface as given by Hanson and Gayler,² this ternary eut,ectic contains about 13 per cent. silicon and 6 per cent. magnesium. All of the alloys discussed here contain excess silicon, so it

Jan 1, 1931

By Frank R. Corwin, Selden S. Rodgers

PAGE I. Introduction,........... 383 11. Brief History of Present MacDoUgall Plant,.... 384 III. First Experimental Work on Increasing Capacity of Furnaces, 385 IV. Effect On MacDouRall Plant of IncreaBed Draft from New Smelter Stack,,.......... V. Increasing the Capacity of the MacDouGall FurnaceS,.. 391 (A). Test of Arthur Crowfoot on Increasing Capacity,.... (a). Description of Test,........ (6). Discussion of Results Obtained from Test,... 393 (B). Investigation Carried Out by John A. Church, Jr.,... 395 (a). Advantages of High Speed,......398 (C). Effect on Regular Operation of Department by Applying Results Obtained from Experimental Work ..... 399 (D). Fundamental Principles Involved in Increasing the Tonnage, . 400 VI. Treatment of an INcreased Amount of Ore Screenings,.. 401 VII. Maximum Percentage oF Ore Screenings in a MacDoUGall Feed, 403 VIII. Tests to Further Increase Capacity of Furnaces,... 406 IX. Tests to Decrease PercentaGe of Flue Dust made by MacDouGall Furnaces,............. (A). Repath-Marcy Furnace......... 408 (B). Modified Hepath-Marcy Furnace,....... (C). Crouse Furnace Designed for Dust Prevention,.... 413 (a). Tests on Crouse Furnace,....... X. Concrete Hearths,.......... 419 XI. Conclusion,............ I. Introduction. Since the first installation of MacDougall roasters at the Great Falls smelter of the Anaconda Copper Mining Co., the capacity of the furnaces.has been more than doubled. During the first nine or ten years of the operation of the MacDougall department the tonnage treated by the furnaces remained practically unchanged. Experimental work carried out in 1906, however, showed that increasing the draft of the furnaces would bring about an increase in capacity. In 1909 the MacDougall department was connected to the new smelter stack and

Jan 1, 1914

By R. S. Shoemaker, F. W. McQuiston

ECOLOGICAL CONSIDERATIONS IN CYANIDATION PLANT PRACTICES Ecological controls of tailing storage pond effluents are mainly concerned with mercury and residual cyanide and are critical problems for gold and silver recovery plant operators. For example, mercury for direct amalgamation of gold ore was used at Homestake until 1970 when the Federal Government acted to prevent further use thereby forcing the abandonment of this practice. However, mercury is still used at Homestake, in South Africa, and also in some Philippine and Canadian cyanide plants for barrel amalgamation of free gold gravity concentrates. The amount of mercury involved in South African practice is about 150 ounces for every 100,000 tons of ore milled and which reaches the tailings ponds. In South Africa, it is obligatory that no pond effluent be discharged beyond the mining property boundaries and waters containing mercury and cyanide must be evaporated either on the tailings pond or in specially constructed evaporation dams. In some cyanide plants such as Carlin and Cortez in the United States, all supernatant solution from the tailings ponds are returned to the plant for reuse. When all solution cannot be reused, the excess may be evaporated in shallow ponds, or by spray systems inside of the tailings dam. Such plant reuse of tailings effluent depends strictly upon the degree of contamination or "fouling" of the barren solution and tailing water with cyanicides. Foul solutions that cannot be returned from the tailings pond may be effectively cleaned up by cyanide regeneration. Cyanogens in plant solutions exist chiefly as free alkali cyanides, as zinc and copper double cyanides, as sulphocyanides, and as ferrocyanides. From the free cyanides and zinc double cyanides, substantially complete recovery of the cyanogen is easily effected. Part of the cyanogen combined with copper is also recovered; regeneration of the remainder with the cyanogen existing as sulphocyanide and ferrocyanides requires special treatment. At this stage, it would be generally more practical to eliminate the remaining cyanogen by chlorination. Ecologists have also been concerned with pollution of ground waters from cyanidation plant tailings. An accute problem is solution seepage down stream from tailings dams and strict attention to prevent or collect any seepage is a real necessity. The tolerance levels of the total cyanide content in potable water set by several U. S. and State health agencies are 10 ppb, and 20 ppb discharged into ground waters. The cyanide content so established is, strangely enough, based on the survival tolerance of fingerling trout. Decanted waste water from tailings dams may be effectively treated by the use of alkaline chlorination for the purpose of destroying all cyanide compounds. The alkaline hypochlorite used to oxidize the cyanide to cyanate is applied as such or generated within the waste solution by adding caustic (NaOH) and chlorine gas. A second chemical reaction involves complete destruction of the sodium cyanate.

Jan 1, 1975

By Ira B. Jorafemon

In the interesting Institute symposium of the preservation of peace by force, through mineral control, one important aspect of the question was not presented. This is the responsibility the United Nations, and particularly the United States, will incur the through limitation of the economic activities of nations that are now friendly to us, as well as of nations that are enemies or are under the control of enemies. After the war all nations, friends as well as enemies will be poor. Hunger and bankruptcy will, will like the sword of Damocles, hang over the heads of all of us on this blundering planet. When the actual fighting is over, there will be a universal attempt to squirm out from under the sword by resuming production of peacetime goods, for trade as well as immediate consumption.

Jan 1, 1944

Sifto Salt Div. of Domtar Chemicals Ltd. has developed a new method for installing roof bolts in the high backs of its 1-million-tpy rock-salt mine at Goderich, Ontario, on the east shore of Lake Huron. The method teams a telescoping- boom hydraulic crane with a specially developed combination auger-drill and bolt-tightening ma- chine. One man, controlling all operations from a basket supported at the end of the crane's telescoping boom, installs an average of 100 5-ft roof bolts per shift, at heights to 45 ft. The mine has very long backs that are not as stable as might be expected. The result has been that roof scaling has occupied an unusually high percentage of the underground work force. About six years ago, company officials decided to go to 100% roof bolting of all backs as a safety measure. The present roof-bolting equipment is the result of a development program instituted at that time to find a faster and more economical method for doing the job.

Jan 9, 1967

Jan 1, 1931

By J. Chipman, N. J. Grant, H. L. Bishop, H. N. Lander

Data of several studies on the equilibrium between molten iron and open hearth-type slags have been combined to determine some of the chemical reactions involved in steel-making. Effects of slag composition and temperature on the iron oxide activity, distribution of sulfur between slag and metal, and the carbon content of the metal are discussed. Also, an overall reaction for the equilibrium between sulfur and oxygen is presented. DURING the past 15 years, a number of significant equilibrium studies have been carried out between liquid iron and simple basic and acid slags in an effort to throw light on the chemical reactions involved in steelmaking. This paper is a summary of the experimental reports on investigations which have been conducted at the Massachusetts Institute of Technology, and of related work in other laboratories. The investigations summarized in this paper include the works of Fetters and Chipman1 and Taylor and Chipman,' which dealt with simple slags that are similar to those found in the open hearth. The sulfur determinations of the slag-metal tests of Fetters and Chipman as reported by Grant and Chip-man" are included. Also, the investigations by Win-kler and Chipman' and Grant and ChipmanQ f more complex slag systems are included in this summary. The experimental procedure is described in detail in each of these papers and will not be discussed. Since the previous reports have been somewhat independent, it is desirable to review and combine the data of the various investigations to determine, as accurately as possible, the reactions in the slag-metal systems of the open hearth. It is the object of this report to present the combined data in such a way as to enhance their utility and applicability. Oxidizing Power of Slags of the System (CaO+MgO)-Si0,-FeO in Equilibrium with Carbon-Free lron The slags selected to determine the iron oxide activity in equilibrium with pure liquid iron were those containing less than 2 pct each of P,O,, MnO, or A1,0, on a weight percentage basis. The method used to calculate activities of iron oxide in liquid slags was that developed by Taylor and Chipman.' The solubility of oxygen in molten carbon-free iron under pure iron oxide slags can be expressed by the following eauation —6320 log (pctO)-------------— + 2.734 [1] where T is the absolute temperature. The oxygen solubility values as determined from Eq. 1 were used throughout this study to calculate the iron oxide activity. The iron oxide activities of slags of various iron oxide contents are plotted in Fig. 1 as a function of the basicity, which is defined as the ratio (pct CaO + pct MgO)/pct SiO,, and are based on molecular percentage values of the components. The percent (FeO), is the total iron content in the slag calculated to FeO. Fig. 1 shows that as the basicity increases at constant mol pct (FeO),, the iron oxide activity increases rapidly and reaches a plateau which extends on the basicity scale from about 1.3 to 2.3; the iron oxide activity then decreases rapidly until a basicity of about 3.0 is reached, where it tends to level off. The solid portions of the curves represent the experimental data of Fetters and Chipman and Win-kler and Chipman. Their experimental heats were made in magnesia crucibles, and hence the slags were saturated with magnesia. The broken lines on the left represent the experimental data of Taylor and Chipman, who used a rotating crucible. In general, these slags contained less than 3 pct MgO. The absence of data for slags containing less than about 40 mol pct (FeO), and basicity ratios greater than about 2.5 made it necessary to calculate curves using ionic concepts of slags. The broken lines on the right, which disregard the solubility limits of di and tricalcium silicate and lime, were obtained by following the treatment of Flood and Grjotheim,"

Jan 1, 1957

By B. W. Vallat

(San Francisco Meeting, October, 1911.) THE Newport mine, located at Ironwood, Gogebic county, Mich., on the Gogebic iron-range, is owned and operated by the Newport Mining Co., for the mining of iron-ore. I. GEOLOGY. The general geology of the Gogebic range has been determined and recorded at different times by well-known geologists,) and their work will be referred to briefly in connection with the local conditions in the mine. The strike of the formation across this property is about 15° north of east. The, general dip is 68° to the north. At the base of the formation on the south lies the granite. Looking north, at right angles to the strike of the formation, we have the foot-wall of quartz-slates and quartzite about 400 ft. wide; the iron-formation about 800 ft. wide, and the hanging-wall of black slates. The iron-formation is composed of banded jasper and quartzite together with iron oxide and concentrations of iron-ore. In character the ore is a soft red hematite, with occasional masses of hard blue "steel ore." The formation is crossed in many places by diorite dikes, which cut through at various angles, the larger or main dikes dipping into the foot-wall in a SE. direction at angles varying from 15° to 30°, while numerous small dikes occur which strike through the formation in a vertical plane and at approximately right angles to the main dikes. There are various theories concerning these dikes, especially as to the time of their origin with relation to the ore-deposition. The commonly-accepted theory is that the dikes were there first, but there are some who contend that they were formed

Nov 1, 1911

By Edna A. Dancy

Jan 1, 1965

By G. Derge, Ling Yang, G. M. Pound

The specific conductance and its temperature dependence were measured over the entire composition range of the molten Cu2S-CuCI system. At a typical temperature of 1200°C, 10 rnol pet of the ionically conducting CuCl reduced the specific conductance from about 77 ohm-lcm-l for pure Cu2S to about 32 ohm -1cm -1, and 50 mol pet CuCl reduced the conductance to that for pure CuCI—about 5 ohm 1cm1. The nature of electrical conduction in molten Cu2S, FeS, CuCI, and mixtures was studied by measuring the current efficiency of electrolysis at about 1100°C. The Cu2S, FeS, and mattes were found to conduct exclusively by electrons, but addition of 1 5 wt pet CUS to Cu2S produces a small amount of electrolysis. Addition of CuCl to Cu2S suppresses electronic conduction, and ionic conduction reaches almost 100 pet at a CuCl concentration of about 50 mol pet. These facts are interpreted in terms of electron energy level diagrams by analogy to the situation in solids. RESULTS of electrical conductivity studies on molten Cu-FeS mattes as a function of composition and temperature have been reported.' The specific conductances ranged from about 100 ohm-' cm-' for pure Cu2S to 1500 ohm-' cm-1 for pure FeS. This is in sharp contrast with the low specific conductance of molten ionic salts for which the transfer of electricity is by migration of ions in the field. In general, these ionically conducting molten salts, such as NaC1, KC1, CuC1, etc., have a specific conductance of the order of magnitude of 5 ohm-' cm-'. It was concluded on the basis of this evidence that molten FeS and Cu,S exhibit electronic conduction. Pure molten FeS has a small negative temperature coefficient of specific conductance, resembling metallic conduction, while pure molten Cu2S has a small positive temperature coefficient, resembling semi-conduction. The molten Cu2S-FeS mattes follow a roughly additive rule of mixtures, both with respect to specific conductance and temperature coefficient. Savelsberg2 has studied the electrolysis of molten Cu2S and Cu2S + FeS. He concluded that while molten Cu2S is an electronic conductor, there is some ionic conduction in molten Cu2S + FeS3 owing to the formation of the molecular compound 2Cu2S.FeS and its dissociation into Cu1 and FeS2-1 ions. The present work does not verify his results. Chipman, Inouye, and Tomlinson" have studied the specific conductance of molten FeO and report a high specific conductance, about 200 ohm-1 cm-1 of the same order of magnitude as that found for molten mattes, and a positive temperature coefficient. They interpret these results in terms of p-type semiconduction in the ionic liquid by analogy to the situation in solid FeO.1 imnad and Derne' detected appreciable ionization in molten FeO by means of electrolytic cell efficiency measurements. In order to verify the conclusion that electrical conduction in molten Cu2S and mattes is electronic, and to gain further insight into the structure of molten sulfides, the following investigations were carried out in the present work: 1) The specific conductance, s of the molten system Cu2S-CuC1 was measured as a function of temperature over the entire composition range. As discussed later, molten CuCl is an ionic substance. It was thought that if molten Cu2S were simply ionic in nature, addition of small amounts of CuCl might not have a catastrophic effect in lowering the high conductance of the Cu2S. On the other hand, if much electronic conduction occurs, addition of the ionic CuCl should have a large effect in destroying the electronic conduction. 2) The electrolytic cell efficiency of the following molten systems was measured at about 1100°C in specially designed cells: Cu3; Cu2S + FeS, 50:50 by wt; FeS; Cu2S + CuS, 15 wt pet; Cu2S + CuC1, 5.9 to 46.4 mol pet; and CuC1. This gives a direct measure of the fraction of current carried by ions in these melts. Further, the cell efficiency, extrapolated to zero ionic current, is given by cell efficiency = (s leasile + s elexstronic). [1] s lucile for molten CulS would be expected to be no greater than that for molten CuC1, whose s lonle is about 5 ohm-' cm-1, as will be seen in the following. u,.,,.,.,.......for molten Cu,S is of the order of 100 ohm-' cm-'.' Thus, a large increase in cell efficiency from 0 to values of 10 to 100 pet upon addition of CuCl to Cu2S would indicate destruction of the electronic conductance. Conductance Measurements Experimental Procedure—The apparatus and experimental method were the same as those described in detail in connection with the study of electrical conduction in molten Cu,S-FeS mattes.' A four terminal conductivity cell and an ac poten-

Jan 1, 1957

Single orders 2.5 c. Pamphlets 10. c. each in lots of three or more. Pamphlets 5 c. each in lots of fifty or more. These prices prevail for orders for pamphlet, of the same or different titles. The pamphlets listed on the following sheets are advance copies printed to facilitate discussion at the meetings of the Institute. They are offered for sale at the reduced prices given above as long as the supply, lasts. This list is published in the Bulletin in order that members may have the first opportunity to secure pamphlets, which sometimes are in such great demand that the supply is exhausted before the wants of members can be supplied. The following list includes only a fraction of the pamphlets that have been published by the Institute. Any other paper published by the Institute may be obtained for the price of $1, except those published in Volume XXXI, which are rare.

Jan 5, 1917

By Dorsey Hager

The possibility of oil and gas production in Alabama his been little considered as yet. Gas and some oil have been found in northwestern Alabama, near Birmingham, in the Pennsylvanian beds, but the oil and gas possibilities in the Cretaceous beds are not generally appreciated. The recent activity of oil companies in that State has attracted much attention, and in this paper the main structural and the general strati-graphic features are described. Four favorable areas are outlined. These contain folds of major interest. There are other favorable areas which have not been mapped-l Commercial pools discovered in this area would have the advantage of being near tidewater. Mobile, Ala., on the Gulf of Mexico, would be the logical site for refineries and shipping facilities. A pipe line could readily be laid to that city from the Hatchitigbee and the Jackson areas. The logical outlet for the Geneva and the Gordon areas would be Panama City, Ha., on the Gulf of Mexico. Topography The whole of the area under consideration lies in the Gulf coastal plain and slopes gently to the southwest and west. The elevations vary from 200 to 400 ft. (60 to 121 m.) above sea level. The streams have sunk their channels into this gently sloping plain, the main drainage flowing south or southwest into the Gulf of Mexico. Between the

Jan 1, 1918

By G. K. Manning, C. H. Lorig

TWO metallurgical tools have acquired wide use within the past several years as a means of studying the transformation characteristics of steel. One is a technique used first by Bain and Davenport for determining the transformation characteristics of a steel at constant temperature; the second is the end-quench hardenability test. Constant-temperature transformation curves like those of Bain and Davenport have done much to rationalize the metallography of steel; however, in commercial practices, constant-temperature transformation is seldom encountered, therefore only rarely can such curves be directly applied. The real reason for the determination of such curves lies in the fact that they provide a way of thinking about transformation that is both convenient and productive. The end-quench hardenability test is a more practical means of studying transformation, for, by correlating positions on the hardenability bar with shapes of different masses, an almost direct application of the results can be made. Unfortunately, the end-quench test, though practical, can do very little toward improving the metallurgists' way of thinking about transformation. These two metallurgical tools, dealing with precisely the same phenomenon, should be very closely associated in metallurgists' minds. Actually, they are frequently pushed into separate mental corners and considered as being more or less distinct and unrelated. The reason for this is that no strong connecting link between them has been developed. An attempt is sometimes made to relate these two tools by projecting the critical cooling rate on the isothermal transformation plot as illustrated in Fig. I. The critical cooling rate is considered as a constant rate-though in practical applications, cooling rates are never constant—and this constant cooling rate is given uniform significance from the Ae temperature down to the temperature of initial transformation. A little thought indicates the errors of such a procedure. Certainly the time interval spent just below point A of Fig. I cannot be as effective in promoting nucleation as is the time interval spent just above point B. Yet the procedure represented in Fig. I considers all the time spent between temperatures A and B to be just as effective in promoting nucleation as though all the time were spent at temperature B. Furthermore, change the shape of the isothermal curve between points B and C in any way desired, and the required critical cooling rate is not changed one iota. This cannot possibly be true. Such a way of thinking about critical cooling rates not only is incapable of giving any results that are quantitatively satisfactory but is likely to give very misleading qualitative results.

Jan 1, 1947

By Frederick Clapp

INTRODUCTION - SCOPE OF DISCUSSION There has hitherto been no systematic effort to make public the available information on petroleum in South America and the object of this paper, therefore, is to broadly discuss the subject as it pertains to South America as a whole, endeavoring to collect in readable form what is known regarding individual fields. This article is not intended to exhaustively discuss individual fields, or to solve the many complicated problems regarding petroleum and natural. gas in the various republics, since those necessitate years of study and work by petroleum geologists, engineers, financiers, and drillers. Neither. can the reader expect absolute accuracy in all statements, since this is impossible at the present time. The writer has, of course, attempted to be correct in all cases, but in a review involving so many countries and extending over so many, phases of the subject, it is to be expected that some errors will have crept in.

Jan 10, 1917

By G. K. Manning, C. H. Lorig

TWO metallurgical tools have acquired wide use within the past several years as a means of studying the transformation characteristics of steel. One is a technique used first by Bain and Davenport for determining the transformation characteristics of a steel at constant temperature; the second is the end-quench hardenability test. Constant-temperature transformation curves like those of Bain and Davenport have done much to rationalize the metallography of steel; however, in commercial practices, constant-temperature transformation is seldom encountered, therefore only rarely can such curves be directly applied. The real reason for the determination of such curves lies in the fact that they provide a way of thinking about transformation that is both convenient and productive. The end-quench hardenability test is a more practical means of studying transformation, for, by correlating positions on the hardenability bar with shapes of different masses, an almost direct application of the results can be made. Unfortunately, the end-quench test, though practical, can do very little toward improving the metallurgists' way of thinking about transformation. These two metallurgical tools, dealing with precisely the same phenomenon, should be very closely associated in metallurgists' minds. Actually, they are frequently pushed into separate mental corners and considered as being more or less distinct and unrelated. The reason for this is that no strong connecting link between them has been developed. An attempt is sometimes made to relate these two tools by projecting the critical cooling rate on the isothermal transformation plot as illustrated in Fig. I. The critical cooling rate is considered as a constant rate-though in practical applications, cooling rates are never constant—and this constant cooling rate is given uniform significance from the Ae temperature down to the temperature of initial transformation. A little thought indicates the errors of such a procedure. Certainly the time interval spent just below point A of Fig. I cannot be as effective in promoting nucleation as is the time interval spent just above point B. Yet the procedure represented in Fig. I considers all the time spent between temperatures A and B to be just as effective in promoting nucleation as though all the time were spent at temperature B. Furthermore, change the shape of the isothermal curve between points B and C in any way desired, and the required critical cooling rate is not changed one iota. This cannot possibly be true. Such a way of thinking about critical cooling rates not only is incapable of giving any results that are quantitatively satisfactory but is likely to give very misleading qualitative results.

Jan 1, 1947

By Granville S. Borden

The fruits of industry are divided between capital, labor, and governments. Capital takes its redemption and remuneration through profits or dividends; labor takes its share through wages; governments take their share through taxes. Each must have a just share, and the question of what is a just share and the question of who-shall make the allocation are vital current political and economic issues. Certain political philosophies con- tend that government should take all the fruits and that some dictator or politician should have irrevocable discretion and power to distribute the fruits. Believers in democracy and free enterprise adhere to the view that capital is entitled to redemption and fair remuneration; that labor shall have a fair wage; and that governments shall make equitable levies. But since all human beings, both individually and in groups, are inherently selfish, there are many variable views in regard to the question of what ratios shall be applied in a division of the fruits and who shall have the power to fix these ratios. Perhaps all parties should devote more energy to means of increasing the crop, and not so much time to quarreling over a division of the existing crop. Moreover, all three parties must guard against killing the goose that lays the mineral eggs. For example, if the tax burden becomes oppressive and the taxpayer refuses to carry it, then business stagnates, with consequent unemployment, reduction of profits, and curtailment of government revenue. If a producer assumes the increased tax burden, marginal operations must be closed down, and again the consequences are increased unemployment and diminished government revenue. Quite often an increase in a rate of tax results in a reduction of government revenue. Perhaps the worst detrimental feature of selfishness and greed on the part of any one of the three distributees of the fruits of industry is the retardation of expansion of the enterprise. Growth means new jobs, more government revenue, better trade, and better standards of living. Explorations and discoveries have resulted in tremendous contributions

Jan 1, 1959

By H. O. Hofman

PAGE Part I. Decomposition OF Zinc Sulphate by Heating in Air, . 811 I. Introduction............ 811 II. Zinc Sulphate Used,..814 III. Fumes and Pyrometers,........ 816 IV. Heating Zinc Sulphate—Dehydration,...... 817 V. Heating Zine Sulphate—Decomposition...818 (a.) Beginning of Decomposition..818 (b.) Rapidity of Decomposition,..819 (c.) End of Decomposition..823 (d.) Retardations in Heating.-Curve,..825 (e.) Formation of Basic Salts,..826 Part II. Decomposition OF Zinc Sulphate by Heating with Carbon (Reducing Roast), .830 I. Introduction,........... 830 II. Experiments and Results ,.........832 III. Summay,........... 834 Part 111. Formation of Zinc Sulphate by Roasting,... 834 I. Introduction,........... 834 IT. Description of Blende,......... 836 III. Outline of Operations,.........838 IV. Details of Experiments.......... 839 1. Decrepitation,.......... 839 2. IgnitionPoint,....839 3. Sulphatizing-Roast of Joplin Blende..840 4. Sdphatizing-Roast of Warren Blemde ,..843 5. Sulphatizing-Roast with Addition of Pyrite...848 6. Summary of Sulphutizng-Roasts,....... 854 Part IV. Appendix : Formation of Zinc Ferrate...856 Part I. Decomposition of Zinc Sulphate by Heating in Air. I. Introduction. With the exception of lead sulphate. all common metallic

Jan 1, 1905