Search Documents

By Bert C. Morrison

In 1961. American Smelting and Refining Company was conducting exploration for lead in southeastern Missouri using several geophysical methods. Electrical methods were used in almost every hole drilled during this period. These methods met with only limited success, with one exception. This paper deals with that exception: An Electrical Potential Method used at a single hole to indicate direction to better mineralization. This method was notably successful in the program.

Jan 1, 1970

By Elmer R. Kaiser

G. A. Vissac (Consulting Engineer, Vancouver, B. C.) —Some of the data presented in this paper, in connection with cost studies of washed coals, should be clarified and qualified. Washing a raw coal down to a low ash content may mean higher losses in refuse, but the cost of the operation may be more than compensated by the increased value of the resultant product. However, careful engineering and accurate machinery are required to insure maximum profits. Washing at a low gravity separation demands a very accurate automatic process, chiefly when the small sizes of coal are being handled. Coal consumers today are buying mostly on a Btu basis, cognizant of the fact that low ash contents result in lower installation costs and in savings in handling and transportation charges. The attached Table X gives the actual balance sheets of the various cleaning operations corresponding to various ash contents for the two coals presented in the paper, using the old technique of a two-products separation. or the new technique, now commonly used in Europe, of a three-way separation made possible by new methods and new equipment. Savings in capital costs, handling, and transportation have been calculated on the basis of a delivered cost f.O.b. plant of $10.00 per ton of coal at 16.5 pct ash (actual 1953 average price reported by Consolidated Edison, N. Y.), and of $3.50 at the mine also for 16.5 pct ash coal. In both cases this corresponds to values of 126 and 4.26 per 1 pct of combustible and per ton, respectively, on delivered and on at the mine prices. As an example, the middle western coal at 16.5 pct ash, raw, washed down to 4 pct ash in a two-way process will give 53.75 pct of clean coal at 4 pct ash and 46.25 pct of refuse at 31 pct ash. The value of the losses will be 0.4625x(100—31)x0.042 = $1.34. Add the cost of washing, capital, and operation, which is $0.35. The total cost will then be $1.69. But with a three-ways separation we will have 53.75 pct of first-grade coal at 4 pct ash, 37.25 pct second-

Jan 1, 1955

By Stefano Ceccotto, Eugenio Trussoni

"INTRODUCTION Contemporary city is made of layers. Physical structures layers (built fabric, residential, commercial industrial etc. ), infrastructural layers (below and above ground), “green” layers (parks and open spaces), and also informational layers, i.e. connections, links, between sectors of the city and other territories. The “city of layers” concept represents the exercise of “rebuilding the city” per each layer, highlighting those physical built structures that are functional to define a relation. For example, if consider the “connection” relation, the city is re-designed by considering only transportation built structures. The layer obtained in such fashion is hence the “transportation” layer, including below grade infrastructures (subways) and above grade lines (rail, bus, tramways etc.), as below shown in Figure 1.In this sense, the contemporary city is represented by separate constructs assembled together according to a specific functionality (e.g. “connection”). As a consequence, the relation between what is built underground, and the related above-ground development, can be perceived in his most evident appearance. What could happen within the contemporary city if the planning process would begin from below to above and not vice-versa?INTERACTION The question risen in the introduction is strategic when approaching the difficult task of designing (or re-designing) a multi-level organism like the contemporary city. Nowadays, the theme of integration between underground and at-grade master planning has become the subject of many urban renovation projects, where the design process has begun within the transportation layer, underground, and further developed by interacting with at-grade structures already existing or in phase of design.A series of case studies where below/above interaction plays a key role in the project will be further analyzed. Moreover, it is relevant to understand the mechanics of an urban transformation process that originates within the transportation layer and ends up with the design of entire sectors of the city. The Transit Oriented Development approach is a useful tool to clearly understand such transformation process. TOD has become, in particular in the last decade, one of the most effective tools for urban design, in order to solve simultaneously the many different instances related to transit planning, urban design and real estate market."

Jan 1, 2016

By Eric R. Achelpohl

The paper follows the introduction of a college student into the explosives industry. The opportunity of experiences from classes and work at the University of Missouri-Rolla, along with summer internship experiences are highlighted.

Jan 1, 1998

By J. H. Swisher

The solubility of sulfur and rate of solution of sulfur in pure Lron were measured in H2S + H2 and H2S + H2 H2O gas mixtures. The solubility and diffusivity of sulfur at 1410°Care 0.13 pet S and 1.0 x 10-5 sq cm per sec, respectively. The solubility iS the same, but the rate of sulfurization is slower in the presence of H2O in the reacting gas. Under these conditions, the over-all rate is controlled jointly by a slow surface reaction and by solid-state diffusion; the mechanism for the surface reaction has not been identified. KNOWLEDGE of the behavior of sulfur in solid iron is desirable for the metallurgy of such products as free machining steel, where a high sulfur level is required, and inclusion-free high-strength steels, where the sulfur specifications are very low. The present investigation was undertaken to check previously reported values for sulfur solubility and diffusivity in 6 iron, and to study the poisoning effect of chemisorbed oxygen on sulfurization kinetics in H2-H2S-H2O gas mixtures. All of the experiments were performed at 1410°C. The thermodynamic behavior of sulfur in 6 iron was the subject of a paper by Rosenqvist and Dunicz.' The sulfur solubility at 1400" and 1500°C was determined by equilibrating pure iron specimens with H2-H2S gas mixtures. The maximum solubility of sulfur in 6 iron was alsc determined by Barloga, Bock, and parlee2 by reacting iron wires with sulfur in sealed capsules. In another investigation, the diffusion coefficient of sulfur in 6 iron at temperatures up to 1450°C was measured by Seibel.3 The method used was to measure sulfur concentration profiles in diffusion couples containing radioactive sulfur EXPERIMENTAL Apparatus. A vertical resistance furnace wound with molybdenum wire and containing a recrystallized alumina reaction rube was used for the experiments. The hot zone in the furnace was approximately 2 in. long with a temperature variation of ±3oC. The hot zone temperature was automatically controlled to within ±2°C, and the test temperature was measured with a pt/Pt-10 pet Rh thermocouple before and after each experiment. Flow rates of the reacting gases were obtained using capillary flow meters. Materials. The source of H2S in the gas train was a premixed cylinder containing 5 pet H2S in H2. This mixture then was diluted with additional hydrogen and argon. In some experiments, water vapor was introduced by passing hydrogen and argon through a column containing 10 pet anhydrous oxalic acid and 90 pet oxalic acid dihydrate. The vapor pressure of water above this mixture is well-known.4 Argon was used as a diluent to minimize thermal segregation of H2S in the furnace5 and to reach higher H2O:H2 ratios than could be obtained in mixtures of H2 and H2S alone. Argon was purified by passage over copper chips at 350°C and subsequently over anhydrone. Hydrogen was purified by passage over platinized asbestos at 450°C and then over anhydrone. The H2-H2S mixture was purified by passage over platinized asbestos and then over P2O5. The specimen stock was made by melting and vacuum-carbon deoxidizing electrolytic "Plastiron" in a zirconia crucible. The principal impurities are listed in Table I. In some of the equilibrium experiments, six-pass zone-refined iron was used to minimize impurity side effects. This zone-refined iron had a total impurity level of about 25 ppm. Procedure. Specimens were annealed in hydrogen for a period of at least 2 hr at the beginning of each experiment. The specimens were held in the reacting gas for times varying between 10 min and 17 hr, and cooled to room temperature in a water-cooled stainless-steel block at the bottom of the furnace. The pH2S/pH2 ratios reported are those for gas equilibrium at 1410°C. Calculations based on available thermodynamic data8 showed that the only other gaseous8 species that formed in significant amounts in the furnace were S2 and S. Even when water vapor was introduced into the gas mixture, the concentrations of SO2, SO, and so forth, were negligible. The initial partial pressure of H2S was therefore corrected for its partial dissociation to S2 and S in determining the equi-

Jan 1, 1968

The American Mining Congress, 841 Munsey bldg., Washington, D. C. J. F. Callbreath, Secretary. The American Mining Congress is a trade association rather than a technical society and as such does not issue scientific papers. Aside from the articles appearing in the monthly Mining Congress Journal, and the Proceedings of the Annual Meetings, only two works have been issued. They are: The standard handbook on mining methods, practice and equipment. $3.

Jan 1, 1933

By K. F. Bailey

Naturally occurring asbestos in aggregate and other mineral deposits, and the release of asbestos fibers into the ambient environment, is a public health concern. Determining the presence of asbestos in an ore body also presents a considerable sampling and analytical challenge. Improper and inaccurate identification of asbestos can result in unwarranted public and worker panic leading to significant costs to mine operators both in terms of dollars and company image. Some companies have been forced out of business simply because they had the non-asbestiform, prismatic variety of one of the six asbestos minerals. In the late 70’s, asbestos was found as a contaminate in a trap rock quarry in Rockville, Maryland. This discovery led to a massive overreaction by federal, state and local governments. In 1986, the Occupational Safety and Health Administration (OSHA) promulgated a final rule that regulated the common non-asbestiform mineral habits of actinolite, tremolite, and anthophyllite as if they were asbestos. The rule was reversed after a six-year struggle. Recently, the Libby, Montana, W. R. Grace vermiculite - asbestos, as well as the California chrysotile in serpentinite, and the New Jersey Southdown quarry – asbestos events have rekindled the entire issue of naturally occurring asbestos. It is time to get this concern addressed with sound science so that real asbestos is properly identified and controlled.

Jan 1, 2002

The Western Australian Mining and Petroleum Research Institute (WAMPRI) was established in 1981 by the Western Australian Government as a funding and co-ordinating Institute to foster research into the mining and petroleum industry within this State. To June 1984, the Institute has sponsored 34 projects with a total notional value of $2.5 million and an actual cash commitment of $1.5 million. Strong support for WAMPRI has come from Industry with 60 companies contributing half the money needed for the research grants.The 34 WAMPRI projects funded so far cover all aspects of the mining and petroleum geosciences.Several WAMPRI projects are concerned with gold including processing technology and the development of exploration models and techniques, they are providing successful results.Although well supported by Industry there is a surprising lack of applications being submitted to the Institute in the area of mining engineering, where it is felt there is much scope for research projects.

Jan 1, 1984

By A V. Ozsever

The selectivity in flotation columns involving the separation of particles of varying degrees of floatability is based on differential flotation rates in the collection zone, reflux action between the froth and collection zones, and differential detachment rates in the froth zone. Using well known theoretical models describing the separation process and experimental data, froth zone and overall flotation recovery values were quantified for particles in an anthracite coal that have a wide range of floatability potential. For highly floatable particles, froth recovery had a very minimal impact on overall recovery while the recovery of weakly floatable material was decreased substantially by reductions in froth recovery values. In addition, under carrying-capacity limiting conditions, selectivity was enhanced by the preferential detachment of the weakly floatable material. Based on this concept, highly floatable material was added directly into the froth zone when treating the anthracite coal. The enriched froth phase reduced the product ash content of the anthracite product by five absolute percentage points while maintaining a constant recovery value.

Jan 1, 2005

The Ravensworth-Liddell area is part of the Muswellbrook- Singleton Coal District of the Northern Coalfield. It lies in the Parishes of Liddell, Ravensworth, Vane and Howick, in the County of Durham, midway between Singleton and Muswellbrook, and is traversed by the Great Northern Railway, and the New England Highway.Ravensworth and Liddell railway stations are 57 miles arid 61 miles, respectively, north from Newcastle (Fig. 1).The area has been the centre of an intensive search for open cut coal during the past few years. More than 1,200 bores, of which about 10% were cored diamond drill holes, were drilled to depths of about 200ft. Portions with thicker cover have been explored by 10 diamond drill holes to depths of over 400ft. but core recovery from these deeper holes was poor, and the lack of detail in the recorded logs limits geological interpretation. The drilling has proved about 34,000,000 tons of open cut coal, and about 246,000,000 tons under deeper cover.GEOLOGYThe Ravensworth-Liddell area lies on the eastern flank and southern extremity of the Muswellbrook Dome, extending from Hebden in the north, to Jerry's Plains in the south, and the rocks under consideration belong to the Tomago Stage of the Upper Coal Measures. On the north they are truncated by the Hebden Thrust fault, which has a throw of about 4,500ft. (Raggatt, 1929). On the west they are bounded by outcrops of the Upper Marine Series, which conformably underlies the Upper Coal Measures, and...

Jan 1, 1953

By John Ward Smith

Detailed oil yield, lithologic, and mineral distribution data are presented for core and drill-cutting samples from the Western Oil Shale Corp. Project Utah EX-1 Corehole (WOSCO EX-I), drilled to sample a deeply buried oil-shale sequence in the Green River Formation of Utah's Uinta Basin. Drilling of this corehole was part of the evaluation of this site for possible oil-shale development by nuclear explosion. Sections sufficiently thick for nuclear development average 15 gallons per ton or less and consist predominantly of low-grade shales. Some properties of low-grade shales may be advantageous to a nuclear experiment by facilitating breakage, fracture development, and in situ retorting. The formation correlates precisely with the well-studied oil shales 25 miles east near the Colorado border. A 235-foot mineralized section containing nahcolite, shortite, and searlesite whose bottom lies 300 feet above the Mahogany zone is described.

Jan 1, 1972

By William Ward

ONE often reads of the rich placer gravels in many of the canoe-traveled rivers of South America. The apparent richness of these gold-bearing gravels impresses the traveler, and in fact he may see batea after batea showing enough colors to figure over a dollar per cubic yard. These workings are called "playas" from the Spanish word playa, meaning shore or beach. Many workings have been reported in tropical rivers, but to my knowledge no dredge has made a success in such deposits. Investigation generally shows that the area of richness is limited and especially that the depth of the rich concentration is hardly ever more than a few inches. The Cauca river in Colombia, South America, is noted for its many rich playas.. This river rises near Popayan in the southern part of Colombia, flows north through a narrow valley between parallel mountain ranges and empties into the Magdalena river near Maganque. The airline distance between source and mouth of this river is only about 500 miles. The rainfall is large and the lower Cauca appears to be about the size of the Missouri river in the United States. From its mouth up to Valdivia, in the State of Antioqua, it is navigable. Above Valdivia is a. narrow gorge, above which the river is again navigable for some distance. The part of the Cauca where the playa panning is most noticeable is from Valdivia down to Where the Nechi river enters the Cauca, a distance along the river of about 100 miles. The current in this part is swift, so that the stern-wheel river steamers make the trip with some difficulty. In the course of my work in this section of Colombia I have had the opportunity to make a study of several of these playa workings and will give in detail the conditions observed.

Jan 7, 1914

By H. C. Theuerer

EVEN the highest purity silicon available for semiconductor use contains significant amounts of donors and acceptors, usually aluminum, phosphorus, and boron. Aluminum and phosphorus can be removed from silicon by adaptations of the zone refining techniques' widely used with germanium. Removal of boron, however, has been a difficult problem. The approximate distribution coefficient for boron in silicon is 0.8, so that while zone refining is possible, it is not very effective in any reasonable number of passes. It has been found, however, that boron can be effectively removed from silicon by treatment of a liquid zone with hydrogen and water vapor. Starting with 40 ohm-cm, n-type silicon, use of zone refining coupled with hydrogen

Jan 1, 1957

By Honorio Oliveros Gómez, Oscar Jaime B. Restrepo

"Colombia produces nine tons of electronic waste per year and there are approximately 60 tons accumulation generated in the last nine years. This work aims to establish a general methodology in the laboratory to recover gold, silver and platinum group present in electronic waste, also explore other forms of recovery of metals contained in electronic waste. We selected seven types of electronic cards present in the computers, which have their parent desoldering electronic components. Initially, we characterized the components of the cards through X-ray diffraction and SEM, to identify the metal species and composition. Tests were conducted laboratory hydrometallurgical recovery of metals. This paper proposes a methodology for laboratory-scale work.INTRODUCTIONColombia produces nine tonnes of electronic waste per year and build there in about 60 tons generated in the last 9 years [1], Computers, TVs, audio equipment, monitors, cell phones, remote controls, printers and operated toys battery, among others are part of this inventory, which mostly comes to landfills, because the lack of legislation to control the final destination of waste electrical and electronic equipment, and lack of efficient technologies to recover materials [2]. Under these circumstances which have environmental implications, technological and economic recovery is essential metals present in the electronic cards of computers, by hydrometallurgical with subsequent base metal electrodeposition [3]. Pyrometallurgical route is discarded by major implications for economic and environmental [4]. Recovery From this perspective, the determination of the metal fraction and the relationship between the different metals, using the SEM characterization techniques - BSE and XRD is indispensable [5] It follows with electrolytic dissociation processes in the leaching and electrodeposition [6], and unit operations in the laboratory to carry out successfully these processes on a larger scale. Were randomly selected computer twenty-four postcards for nine types of cards have different functions in the computer, which, through the absorption desoldering technique, they broke the resistance (thermal, surface, photoresist, power), capacitors (ceramic, electrolytic), diodes (silicon, germanium, high frequency), transistor (NPN, PNP), processors, integrated (high, medium and low frequency), the RAM card and pin parallel port serial"

Jan 1, 2011

By K. A. Wheeler

To evaluate the effects on groundwater of a proposed in-pit disposal operation at an east Texas lignite mine, the local geologic, hydrogeologic, and geochemical features were thoroughly characterized. Resultant data were used in a flow and transport model (SWIFT) to simulate migration of the ash leachate. Computer simulations indicate that the leachate plume will travel 61-152 meters from the disposal area in 100 years after resaturation of the spoils. A 61-meter buffer zone of mine spoils without ash will surround the disposal area. The proposed landfill operation received regulatory approval and is currently operating as a Class 2 non-hazardous landfill.

Jan 1, 1994

By A. W. Hahn

ALTHOUGH enormous tonnages of sulfide lead and lead-silver ores are treated by flotation, the products of flotation mills treating oxidized ores of lead and silver are almost negligible. However, each year there is a slight tonnage increase, and it is possible, should a sizeable oxidized lead ore tonnage be developed, the field will become an important one. In 1918, the Shattuck-Arizona Copper Co. erected a plant at Warren, Ariz., for the treatment of oxidized gold-silver-lead ores. Glenn L. Allen worked out the metallurgy for this plant, employing tabling, followed by flotation concentration. The Shattuck-Denn Mining Co., successors to the Shattuck-Arizona Co., now employs straight flotation in the same mill, treating about 200 tons daily. In 1922, the San Diego mill of the American Smelting & Refining Co., in the Parral district, Chihuahua, Mexico, started operating a 600-ton mill on a mixed sulfide-oxide gold-silver-lead ore. Tables and flotation are used here, and about 200 tons of oxidized slime treated by flotation. In 1923, the Eureka Holly Mining Co. started operating a 90-ton mill at Eureka, Nev., using tables and flotation, on an oxidized lead-silver ore. In 1924, the American Smelting & Refining Co. started a 250-ton mill in northern Peru, to treat a high-grade oxidized gold-silver ore with very low lead values. In 1924, the Grand Central Mining Co. started a 200-ton flotation mill on old oxidized gold-silver-lead tailings at Fairbank, Ariz. In 1926, the Compania Internacional Minera, a subsidiary of the Union Corporation of London, started a 250-ton flotation mill on oxidized lead-silver ores, and during April of this year, the Phelps-Dodge Corpn. will probably start a 250-ton mill at Warren, Ariz., on oxidized lead-silver ores, similar to those being treated in the Shattuck-Denn mill. METHODS All of these mills use sodium sulfide for filming the oxide minerals, with the possible exception of the North Peru mill, and all use oily reagents. The total tonnage of strictly oxidized lead-silver ores concentrated by flotation is probably less than 2500 tons daily. The following figures give the various types of ores being treated:

Jan 1, 1928

By C. S. Smith, L. W. Kempf, C. S. Taylor

The thermal conductivity of aluminum alloys is of considerable industrial importance. This is particularly true in such applications as internal-combustion engines where one of the principal reasons for the use of these alloys is their relatively higher thermal conductivity. In spite of this, relatively few data are available on this property of aluminum alloys. The reason is quite apparent to anyone concerned with the experimental determination of coefficients of thermal conductivity. This determination, in theory so simple, is extraordinarily difficult if any high degree of precision is desired. Fortunately, some .knowledge of the relationship between thermal and electrical conductivity has permitted the use of the latter physical property in deducing the relative approximate values of the thermal conductivities of metals. This fundamental relationship, first enunciated by Wiedemann and Franz' as applying to metallic elements and later shown by Lorenz2 to be applicable to alloys within a single metallic system, has been of service in the industrial application of metals. The electrical conductivity of metals is easily determined with a high degree of precision. It is, therefore, quite desirable that the relationship between electrical and thermal characteristics be determined with the greatest possible precision. This paper presents data on the electrical and thermal conductivities of a number of aluminum alloys of industrial importance. Literature on Thermal Conductivity of Aluminum Alloys Masumoto3 determined the electrical and thermal conductivities of 18 aluminum alloys. His results indicated a relatively constant relationship between thermal and electrical conductivity.

Jan 1, 1937

By S. R. Goodman, Hsun Hu, R. S. Cline

The quenching technique has been used to study phase relations in the composition area 2FeO.SiO2-FeO-SiO2-MnO.Si02-ZMnO.SiO2 of the system iron oxide-manganese oxide-silica under strongly reducing conditions such as exist in a gas mixture consisting of equul parts of carbon dioxide and hydrogen. Liquidus and solidus temperatures of most mixtures in the composition area studied are in the range of 1173° to 1345°C. EQUILIBRIUM relations existing among the oxides of iron, manganese, and silicon are of particular interest in two areas of steelmaking: slags and ingot inclusions. Mixtures of these oxides represent about 90 pct of the slag in the acid steelmaking process, and so dominate the chemistry of the whole refining process. These constituents also play an important role in the early slags existing at the time of the "lime boil" in the basic open hearth process. If these slags are liquid, they "wet" the lumps of lime rising from the bottom of the bath, and react with them. A liquid slag rich in CaO is then formed at the very beginning of the refining. Because the temperature is still low, all conditions for a good dephosphoriza-tion are fulfilled at this stage of the operation. Metal deoxidized with ferromanganese or silico-manganese is likely to contain, as inclusions, phases made up from among the oxides of iron, manganese, and silicon. A knowledge of stability relations existing among the phases present in this system, therefore, enables one to predict the hardness of the inclusions encountered. Moreover, because the shape of the inclusions in steel has a profound influence on the physical properties of the metal, it is important to establish whether or not the oxidic material is present as liquid or crystalline phases during heating and rolling of the steel (-1150 to 1350°C). A knowledge of melting relations in synthetic mixtures of iron oxide, manganese oxide, and silica will give a clue to these problems. Methods for determining such relations and the results obtained are described iln this paper. I) PREVIOUS WORK A number cf previous studies have dealt with the three "binary"* systems bounding the system iron oxide-mangar,.ese oxide-silica. The system iron oxide-silica was studied by Bowen and shairerl in 1932. Their data were obtained by equilibration of mixtures in contact with metallic iron. Phase relations for the system iron oxide-silica ill atmospheres of different oxygen pressures car1 be derived from data on the system FeO-Fe2O3-SiO2 as determined by Muan.2 The diagram shown iri Fig. l is a section of this system in an atmosphere of CO2 and H2 in ratio 1:l. The system manganese oxide-silica has also been the subject of several investigations. Most of the early studies suffered from a lack of proper control of the atmosphere under which the equilibrations were carried mt. Phase diagrams for the system at two well defined levels of oxygen pressures have been determined recently. Glasser3 determined stability relations in an atmosphere consisting of carbon dioxide and hydrogen in ratio 5:1, diagram Fig. 2, and Muan4 studied phase relations in the system in air.

Jan 1, 1962

By W. F. Holbrook, T. L. Joseph

The problem of sulfur control is important in all blast-furnace operations but particularly for certain grades of steel because of the rigorous specifications. During the past decade the tendency has been to produce pig iron and hot metal of lower sulfur content. As most of the sulfur in the iron originates in the fuel, the use of high-sulfur coke demands modifications in practice to meet sulfur specifications. While it is generally known that high temperatures and more basic slags favor desulfurization, operators as a rule produce the most acid slag that will permit proper desulfurization. The viscosity of blastfurnace slag has been thought to be related to desulfurization and has been investigated by Feild and Roysterl, also McCaffery and his associates*, but apparently no systematic effort has been made to determine the relative desulfurizing powers of slags over the range of composition encountered in practice. Development of Testing Method Because slag and metallic iron are immiscible, the desulfurization reaction is heterogeneous, occurring only at the interfaces between slag and metal bodies. In the blast furnace the newly reduced iron, containing FeS, descends through the slag bath probably either as small drops or streams, at the interfaces of which desulfurization occurs. After its descent through the slag the iron collects to form a bath of metal, at the top surface of which desulfurization reaction probably occurs. These two steps have been thought to account for all desulfurization in the blast furnace. Kinney3 found that metal removed from the blast furnace just above the tuyeres contained three to four times as much sulfur as the iron at cast. Herty and Gaines4 conclude that most of the sulfur is removed while the metal is passing through the slag. Mund, Stoecker

Jan 1, 1936

By Peter Broad

"Extracting any metal, especially specialty metals and rare earth elements, requires an in-depth analysis of the costs and potential revenue as well as a due diligence study of other stakeholder interests. Rare earth projects are generally in the billion dollar US range or above, and thus failure to accurately predict any loss of revenue caused by impurities within the product or additional effluent treatment costs can destroy an otherwise viable study. Two prime sources of input impurity are considered: impurities in the material feed and from reagents. The effect of these impurities factor on both the product (in reduced revenue) and on residual “tailings” that may incur additional unforeseen costs.INTRODUCTION“Truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident” – Arthur SchopenhauerThe era of unscoped, unbudgeted construction ended about 150 years ago. Today’s engineer must design with confidence; but do so amidst proprietary secrets and unfamiliar pollutants, which present a myriad of interesting challenges. Is it possible to build a viable rare earth plant to a realistic budget, without destroying that which we cherish? Some see this as contradictory but in reality it is the only viable option.WHEN GOOD PROJECTS FAILWithout rare earths the Copenhagen agreement might be null and void. Running a wind turbine with a 30 tonne conventional magnet requires some hefty engineering and prohibitive investment. Despite their ‘Green metal’ applications, production of rare earths have created environmental nightmares, as Folger stated in 2011 when visiting Baotou, or has Jaing Mainheng who has been quoted by Ambrose Evans-Pritchard 6 Jan 2013. This comment is not a criticism of China; the details are from a 2012 white paper published by the Chinese Government that initiated a $6 billion environmental clean-up. Nor is China unique; other plants have had problems as well. There were toxic leaks in the 1990s from Mountain Pass, and the Mitsubishi Bukit Merah Plant (built in Malaysia in 1958) required a $100 million clean-up."

Jan 1, 2016