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By A Hitchen

A general outline is given for the determination of copper, nickel, cobalt, zinc, lead, cadmium, bismuth, manganese, uranium, molybdenum, vanadium, sulphate and fluoride by polarographic or amperometric methods in a variety of ores or metallurgical products. The detection of oxygen in gas mixtures by an amperometric method used as a safety device is also discussed. Introduction I N this paper, a general outline will be given of the polarographic and amperometric methods used for the chemical analysis of various ores and metallurgical products in the Chemical Analysis Section of the Extraction Metallurgy Division of the Mines Branch. The methods to be discussed will be confined to those based on the use of normal D.C. polarography and will not include those methods which utilize a cathode-ray, square wave, pulse or A.C. type of polarograph. For the sake of convenience, ? the polarographic methods will be discussed according to the type of supporting electrolyte employed, as the same electrolyte may serve to determine more than one element in more than one type of ore. Amperometric methods will be discussed according to the element to be determined rather than

Jan 1, 1965

By E. Chin

The Asia and the Pacific region has large mineral resources of antimony, barite, bauxite, bismuth, copper, fluorspar, gold, graphite, iron ore, magnesite, mica, rare earths, salt, talc and pyrophyllite, titanium, zinc, and zirconium. The region overall lacks large resources of oil and natural gas, but it has large resources of anthracite and bituminous coal. In terms of exploitation, many minerals, metals, and fuel are produced in significant quantities in the Asia and the Pacific region as shown in table 1. Collectively, the area accounts for a substantial amount of the world production of antimony, barite, bauxite, fluorspar, gold, graphite, ilmenite and rutile, iodine, iron ore, lead, magnesite, manganese, nickel, salt, tin, tungsten, and zinc. Total coal production of the region exceeds 1.6 billion metric tons. The production of bituminous coal accounts for more than 80 % of the total output. China is the region's largest coal producer, with an output of almost 1.1 billion tons. Other major producers are Australia and India. The combined production by Australia, China, and India is more than 1.5 billion tons or 93 % of the area's output. The remainder of the coal output in the region comes from Afghanistan, Cambodia, Indonesia, Japan, the Korean peninsula, Malaysia, Mongolia, New Zealand, Pakistan, the Philippines, and Taiwan. The production of crude oil throughout the Asia and Pacific region is close to 2.4 billion barrels. China and Indonesia together account for 67 % of the total output. The remainder of the output is primarily from Australia, Brunei, India, and Malaysia. Indonesia is the largest producer of natural gas in the region with an output of close to 58 billion cubic meters, followed by Malaysia and Australia with 23 and 22 billion cubic meters, respectively. Other producers in the region of lesser stature by output include Brunei, China, India, and Pakistan.

Jan 1, 1993

By Harlowe Hardinge, R. C. Ferguson

Laboratory and plant data covering 12 different operations show that lower than "standard" ball mill speeds increase grinding efficiency. In the case of high pulp-level mills, the gain is so great that the increase in capital cost of the larger lower speed mill will pay for itself in less than a year's time.

Jan 1, 1950

By Y. Zhou, G. Chisakuta, P. Bwando, G. Mitshabu

A newly started copper hydrometallurgical plant was confronted with a manganese oxidation issue in electrowinning. This oxidation, in the absence of the amount of iron required to stabilise the electrolyte oxidation-reduction potential, is known to produce oxidants (MnO2, MnO4) that can cause accelerated degradation of the organic phase components in solvent extraction and corrosion of lead anodes in electrowinning. The overpotential required to build up the protection layer on new anodes causes an increased electrolyte potential that creates oxidized species in the electrowinning tankhouse, and these species come back to solventextraction plant with the recycled spent electrolyte. This paper discusses the impacts of manganese oxidants on the health of a plant organic phase. It also outlines the actions taken using iron scraps and sulfur dioxide to mitigate the problem that happened due to the lack of ferrous iron sulfate available on site, as recommended for better control.

Jan 1, 2023

By João Lucas Ribeiro e Fernandes, Geraldo Lúcio de Faria, Altair Lúcio de Souza

A ovalização de bobinas é um problema recorrente no processo de fabricação de tiras de aços médio carbono por laminação a quente. Mesmo com o sucesso da etapa de laminação, a ovalização posterior de bobinas pode ocorrer, gerando transtornos à operação e aumento de custos de fabricação. Alguns autores apontam que o fenômeno de ovalização de bobinas pode ocorrer devido a aspectos metalúrgicos, mecânicos e geométricos. Estudos disponíveis na literatura técnica já exploraram as possíveis causas mecânicas e geométricas. Entretanto, existem poucos dados disponíveis que abordem o aspecto metalúrgico, ou seja, o efeito da decomposição tardia da austenita durante, ou mesmo após a etapa de bobinamento. Nesse contexto, este trabalho se propôs a avaliar, por meio da aplicação da técnica de dilatometria, a possível influência das transformações de fases tardias como uma das causas de ovalização em bobinas de um aço do tipo SAE 1050. Ciclos térmicos que simulam, com boa aproximação, algumas possíveis condições de resfriamento acelerado e bobinamento da tira foram aplicados em corpos de prova padronizados em um dilatômetro de têmpera. Diferentes combinações de velocidade de resfriamento e temperaturas de bobinamento foram avaliadas, sendo possível sugerir que uma diminuição na velocidade de resfriamento da tira após a laminação e um pequeno abaixamento na temperatura de bobinamento, em relação aos valores atualmente utilizados na indústria, pode diminuir significativamente a influência da componente metalúrgica na ocorrência da ovalização nesse tipo de aço.

Oct 18, 2019

By Richard DePew, Robert J. Auber

The Westerly Storage Tunnel is a 25-foot diameter segmentally lined storage tunnel that is a major component of the Northeast Ohio Regional Sewer District's Project Clean Lake that is designed to capture 39 million gallons of untreated CSO overflows from entering Lake Erie. During the final stages of the project completion, a large-scale rock fallout incident occurred during the final lining installation operations at the down-stream end of the tunnel that extended beyond the designed primary support system. This paper outlines the level of coordination and collaboration between the Owner, Designer and Contractor to remediate the situation safely, quickly and effectively.

Jun 23, 2024

By Gupta R. C

Direct reduction of iron ore by solid reducing agents have been studied extensively and summarised by several authors (Otsuka and Kunii, 1969; Abraham and Ghosh, 1979; Frauhan, 1977; Rao, 1971; Kawasaki, Sanscainte and Walsh, 1962; Ghosh, 1970; Rao, 1979). While studying the reduction behaviour, it is generally agreed that the reduction occurs via gaseous intermediate, generated by carbon gasification reaction which involves mass transfer, heat transfer nucleation and growth, etc through a) reduction reaction occurring at solid reductant, and b) reduction reaction occurring at solid iron oxides, thus making the overall reduction process very complex in terms of clearly defining the reduction kinetics of the system. In addition to this, practical difficulties like correctness of reaction temperature, (Seaton, Foster and Velasco, 1983) difficulties in isothermal temperature studies of reduction, difficulties in monitoring the reduction process while using gaseous reductants and separation of reduction by volatile matter from overall reduction process make the reduction kinetics more complex (Misra).

Jan 1, 1999

By Clarence Zener

The internal friction of nonferrous metals vibrating at low stress amplitudes has so far always been successfully interpreted in terms of inhomogeneities of one sort or another. Examples are the fluctuation of stress across a specimen vibrating transversely,1,2,3 the stress inhomogeneities due to the elastic anisotropy and partial random orientation of the individual crystallites, localized weak regions introduced by cold-working,6'7 grain boundaries and possibly twinning planes.8'9 Perfect single crystals are, by definition, homogeneous. Actual single crystals usually, perhaps always, contains some imperfections. The present investigation was undertaken to determine whether the internal friction of single crystals may likewise be attributed to inhomogeneities. This study was made possible through the gift of a large single crystal of 70-30 alpha brass by H. L. Burghoff, of the Chase Brass and Copper Co. The specimen, 3.i in. in diameter and 10 in. long, was similar to samples previously described by Mr. Burghoff. Experimental Method The experimental method used has previously been described in institute papers.5'6'9 The measure of internal friction adopted here, I/Q, is X the logarithmic decre- ment, a measure used by some writers, and is also X the specific damping capacity, a measure used by other writers. In all measurements the stress level was kept so low that the measurements were independent of stress level. In all measurements in which the temperature was varied, observations were made as the specimen slowly cooled from its highest temperature. The specimen was vibrated transversely. Observations were made at the fundamental frequency and at the first overtone, of about 620 and 1710 cycles per second, respectively. No attempt was made to avoid acoustical losses. Experimental Results The specimen was annealed for several hours at 450°C. The temperature dependence of the internal friction was then determined from room temperature to 400°C. As shown in Fig. I, the internal friction increased by only a factor of 2 from room temperature to 300°C., then by a factor of 100 during the next Ioo° interval. These measurements are consistent with the view that the observed internal friction is the superposition of two distinct parts. One, dominant at room temperature, is nearly independent of temperature. This part may be accounted for by acoustical losses and by transverse thermal currents. It was not further investigated. The second part, when plotted in the manner of Fig. I, lies upon a straight line. Therefore it has a heat of activation H; i.e., it varies with temperature as Internal friction e-H/RT [I]

Jan 1, 1943

By Clarence Zener

The internal friction of nonferrous metals vibrating at low stress amplitudes has so far always been successfully interpreted in terms of inhomogeneities of one sort or another. Examples are the fluctuation of stress across a specimen vibrating transversely,1,2,3 the stress inhomogeneities due to the elastic anisotropy and partial random orientation of the individual crystallites, localized weak regions introduced by cold-working,6'7 grain boundaries and possibly twinning planes.8'9 Perfect single crystals are, by definition, homogeneous. Actual single crystals usually, perhaps always, contains some imperfections. The present investigation was undertaken to determine whether the internal friction of single crystals may likewise be attributed to inhomogeneities. This study was made possible through the gift of a large single crystal of 70-30 alpha brass by H. L. Burghoff, of the Chase Brass and Copper Co. The specimen, 3.i in. in diameter and 10 in. long, was similar to samples previously described by Mr. Burghoff. Experimental Method The experimental method used has previously been described in institute papers.5'6'9 The measure of internal friction adopted here, I/Q, is X the logarithmic decre- ment, a measure used by some writers, and is also X the specific damping capacity, a measure used by other writers. In all measurements the stress level was kept so low that the measurements were independent of stress level. In all measurements in which the temperature was varied, observations were made as the specimen slowly cooled from its highest temperature. The specimen was vibrated transversely. Observations were made at the fundamental frequency and at the first overtone, of about 620 and 1710 cycles per second, respectively. No attempt was made to avoid acoustical losses. Experimental Results The specimen was annealed for several hours at 450°C. The temperature dependence of the internal friction was then determined from room temperature to 400°C. As shown in Fig. I, the internal friction increased by only a factor of 2 from room temperature to 300°C., then by a factor of 100 during the next Ioo° interval. These measurements are consistent with the view that the observed internal friction is the superposition of two distinct parts. One, dominant at room temperature, is nearly independent of temperature. This part may be accounted for by acoustical losses and by transverse thermal currents. It was not further investigated. The second part, when plotted in the manner of Fig. I, lies upon a straight line. Therefore it has a heat of activation H; i.e., it varies with temperature as Internal friction e-H/RT [I]

Jan 1, 1943

By Chao Li, Shi Sun, Hongxu Li, Jiaqi Fan, Liangtian Wei

Aiming at the recovery of copper from smelting slag, a flotation approach was studied. It was found that this slag composed of fine particles with complex association and distribution, in which bornite was the main copper-bearing mineral after a detailed mineralogy analysis via polarizing microscope, SEM and XRD. Consequently, flotation was attempted to recycle Cu in slag containing copper sulphide components. Three key factors affecting flotation were ascertained, namely, grinding fineness, the collector and the pH value, while the recovery of Cu estimated by ICP and XRF. Copper concentrate grading at 14.47 with 79.66% Cu recovery was obtained, in the condition of the grinding fineness of −0.074 mm and the proportion of 80%, reagent dosages of 50 g/t for butyl xanthate and a pH value of 10 adjusted using Na2CO3.

Mar 1, 2017

By Bowen Li, Jiann-Yang Hwang, Mingsheng He, Huaguang Wang

Kyanite is one of the major high-alumina minerals for producing refractory ceramics. At high temperature, kyanite can be decomposed into mullite and amorphous silica. This change is an irreversible decomposition and provides potentials for fiber reinforcement of ceramic matrix. In this study, kyanite powder was compressed into a cylinder green body of ceramic and heated at 1150–1450 °C.The phase transformation of kyanite and sinterability were investigated by X-ray diffraction and scanning electron microscopy. The results showed that the phase transformation of kyanite started at 1150 °C when rising the temperature. At 1350 °C, kyanite is completely converted into mullite and silica. The compressive strength of the ceramics reached 73.3–134.8 MPa, while the bulk density was 1.95–2.47 g/cm3. The microstructure indicated the correspondence of the compressive strength to mullitization degree of kyanite.

Mar 1, 2017

Coal, America's most abundant fossil fuel, is expected to play a key role in our pursuit of energy independence. A substantial increase in coal exploitation will be required if we are to fulfill our future energy needs. It is essential that new developments continue if stable coal prices are to be achieved and maintained. The challenge of the mining industry is to continue these developments in the face of problems related to increasing labor costs, inflation and environmental restoration. With expectations of increased activity in surface coal mining, the U.S. Bureau of Mines has authorized this study to determine the preliminary economic and technologic feasibility of underspoil haulage in area strip coal mines and to identify geologic and geographic areas where such a system could be used. These objectives were met by literature search, data-gathering visits to several active area strip mines and by analyzing various haulage systems that were superimposed on three model mines. Potential advantages of such a system include: 1) improved mine design; 2) lower mine operating costs; 3) improved land reclamation; 4) lower manpower requirements; 5) lower mobile equipment requirements; and 6) smaller, less sophisticated maintenance facilities.

Jan 1, 1975

By Xie Longshui

INTRODUCTION The gold production is from the state-owned gold mines, the local gold mines and the by-product of metal mines. Since 1975, the small gold mines have developed in rapid strides. Currently, there are about 3000 small gold mines in China. Most of them are operated by the local, and the production is about 50% of China's gold output. In the small gold mines, the normalized mining equipments are employed at most of mines, but some mines still use such backward tunnelling and mining tools as pick, shovel and hand hammer etc.. The mining techniques have developed from the primitive to the advanced, especially the methods of open stope, shrinkage and filling have been widely used. Such new mining techniques as bolting, vibrating draw, non-electric ignition and diamond drilling etc. are also introduced in the wall gold mines. In recent years, the development of small gold mines is very fast under the guidance of new mining policy which is ' rapid and great development of large-sized mines, helping small mines to develop, and quick mining for the existing mines; and encouraging the collective and the individual to operate a mine.' GEOLOGICAL FEATURES The gold veins are dominant, which are divided into two types, ie. the mesothermal deposit with altered rock in a crushed zone and the hypothermal deposit with quartz veins. The orebody distribution is not centralized, and the size of deposit and single minable orebody is small respectively. Most of deposit dip at 30° to 50°, characterized by expansion and shrinkage, ramification and compound, thinning out and reappearance, separation and composite at the parallel veins etc.. The ore grade is variable, and the factor of grade change is above 100%. The waste zones with lean or submarginal ore usually exist in deposits. As for the gold deposits with altered rock, the ore boundary is indistinct. Most of gold deposits, particularly the gold deposits with altered rock, are intruded by the late structural rock, thus the faults and joints are developed, and the rock and ore are crushed, especially the host rock of roof wall is very crushed. It ie obvious that the conditions of both formation of deposit and mining are considerably complicated. HISTORY With a long mining history and rich experiences, the local gold sectors are small, but they play an important role in China's gold mining industry. Dated from Xia and Shang Dynasty, the gold goods was made. In the Tang Dynasty, the development of gold mining industry was very fast. A Chinese poem , written by Liu Yuxi -- one of famous poets in the Tang Dynasty, says: As sun is shining over Dengzhou land, The fog on river slowly goes away, The panning girls together meet at bay, The beauty's jewels and stamps of king are gold from river sand. This poem shows the local gold mining was flourishing at that time. In 1888, the local gold mining sectors were all the rage at the moment, and the annual output of gold was as high as 21.5 tons. Since the founding of New China, the development of local gold mining was subjected to several back- sets, but certain advances are made on the whole, especially since 1970. Round about 1970,the simple, backward and indigenous mining was dominant in the small gold mines; for instance, the hand-hammer drilling, the hand-operated winch hoisting and the hand haulage etc.were main methods of gold mining . Up until the late 1970s,great changes took place in stoping, haulage and so on. Currently, some advanced technology and large-sized equipments are adopted in the local gold mines. Generally, the local small gold mining sectors play an important role in development of China's gold mining industry, and are important and attractive sectors. PRESENT DEVELOPMENT

Jan 1, 1987

By Raúl Veramendi

El presente texto describe la aplicación del sistema electrónico en las operaciones de voladura de la mina Cuajone. En ese sentido, los detonadores electrónicos son usados para incrementar la fragmentación en la voladura de rocas aplicando los tiempos de retardo óptimos entre taladros para conseguir la interacción de ondas (Ondas P y S) que incrementa y maximiza los esfuerzos de tracción.

Sep 19, 2006

By Yasser Ghobara

Phosphorus is a problematic impurity that has challenged steelmakers for decades. Steel producers have developed specific technologies to eliminate phosphorus prior to and during steelmaking. These process technologies reduce phosphorus to various degrees and increase the cost of making steel. The state-of-the art dephosphorization technologies are described and operating costs compared for each of the established technologies. Costs are discussed in terms of price penalties for high P iron ore and selling premiums for low P steel. From this, strategies to control P in a cost effective manner are described.

Aug 17, 2017

By J. Chipman, N. J. Grant, R. Rocca

D. E. Babcock (Republic Steel Corp., Youngstown, Ohio)—With reference to eqs 7 and 8, at what temperature do they apply John Chipman (authors' reply)—That was 1600°C. Dr. Babcock—You have l x 10-4 as the component for the lime and 1 or 4x10-. Now, is it by dividing one into the other you get the 400? That is assuming equivalent activity on the part of oxygen, sulphur, and magnesia. Dr. Chipman—Yes, they are calculated for 1600. Now, the first one for CaO was calculated before we had a glimpse of Dr. Rosenqvist's paper." If you take his calculation you get 14,000 cal which is very good agreement, but our calculation would be superseded by Dr. Rosenqvist's new data. Dr. Babcock—The state you assume those to be in is the liquid state, as near as you can measure? Dr. Chipman—Naturally it is based on the solid CaS, but if you add the effect of fusion on both sides it just about balances out, so the ratio would be about the same. B. M. Larsen (U. S. Steel Co., Kearny, N. J.)—If we knew the activity of sulphur in the slag instead of merely the percentage, we might be able to find some conflicting factors that balance one another out, and find that the FeO or oxygen pressure effect is really present over the whole range. Dr. Chipman—I am fairly sure we would. The activity of sulphur in the slag and the activity of CaO in the slag, if we just knew those quantities, would enable us to save a lot of this computation and assumption and all the approximations we are doing now. Mr. Larsen—Two other points perhaps should be included: 1—an independent effect of manganese in helping the desulphurization; and 2—the number of mols of constituents or number of mols of ions or whatever there is in the slag could vary with these compositions in such a way that you get dilution effects. Dr. Chipman—You can figure all that in if you want to and it might improve the degree of approximation a little bit. Maybe enough to justify the labor of calculation, inaybe not, but we did not do it. L. S. Darken (U. S. Steel Co., Kearny, N. J.)—The authors have tackled a very complicated problem in trying to tie together in one picture the desulphurizing problem over the wide range of basicity and oxidation level from that of the open hearth to that of the blast furnace. At the present state of our knowledge of slags such an ambitious undertaking necessarily involves the adoption of numerous hypotheses. Their formulation (eq 11) for the higher FeO range

Jan 1, 1952

By Violeta Vigo Vargas

Ante el problema de comprensión lectora y matemática en la educación primaria en la región de Cajamarca, se planteó un proyecto que reduzca el porcentaje de problematización de comprensión y diserción escolar. En ese sentido, el presente texto describe el proyecto que ALAC presenta a través del PRIE. Los objetivos principales son: contribuir a mejorar la calidad y la equidad en la provisión de los servicios de educación y salud en Cajamarca, movilizar talentos y recursos empresariales y públicos, así como contribuir a eliminar las brechas en educación rural de nuestros niños.

Jan 1, 2013

By Roger Lafrance

"This paper discusses various aspects affected by the use of large-diameter boreholes in underground mines. Topics covered consist of noxious fumes, vibrations, post-blast effects, various types of explosives, the cordine system in production blasts, the slider primer system and wall-control methods. In general, the paper is an overview of this important fact of underground mining.IntroductionWith economical factors leading the way, many reasons motivated drilling equipment companies to develop equipment that can drill holes up to eight inches in diameter and even larger for underground applications. One of these other reasons is the fact that many orebodies were considered marginal, given the high costs of conventional mining methods utilizing small diameter boreholes. With these criteria in mind, accelerated programs were put in motion to develop equipment that would reduce both-development and production costs in underground mines. Change s in any basic program often affect other areas down the line. This is particularly true with the ad vent of large-diameter boreholes underground.C-I-L Inc. is certainly no stranger to this phenomena. Whether production headings increase in size and tonnage or whether production increases due to lower costs, one fact remains unchanged and that is the fact that all development and production holes are loaded and blasted whether they be of small or large diameter. Due to this fact, C-I-L Inc., as a leading explosives manufacturer, initiated a program to examine blasting methods in use in surface work with the intent of revising these method s for underground applications. Research facilities were also oriented toward developing appropriate products. This was a task that was accepted with anticipation, with the result that many new blasting systems and methods were brought forward, thanks to the collective efforts of both the consumers and manufacturers."

Jan 1, 1984

By Nixon J. C, Reynolds C

Three principal features of the ore at Captain's Flat, New South Wales, tend to complicate concentration of the valuable minerals, these being:1. The ore occurs in three more or less separate bodies which vary in texture and mineral ratios. Mining of constant proportions of the three sections, or adequate blending of the ore, is not fully effective, and consequently the flotation section is subjected to feedof varying texture.2. The mineral association in the heavily pyritic ore is extremely intimate. Composite particles exist even at 20 micron sizeI, and probably finer.3. The copper content of the ore averages_about 0,6%, which is high enough to justify recovery of the chalcopyrite in a separate concentrate. A review of the metallurgical history of the mine shows that this feature has been the cause of the several major changes in flowsheet of the flotation section since the commencement of milling.METALLURGICAL HISTORYThe mine started production in January 1939, at the rate of 250 tons per day of sulphide ore, assaying 0·68% Cu, 6·52% Pb, 10·8% Zn, and about 1 dwt. Au and 2 oz. Ag per ton.

Jan 1, 1952

By H. H. Murray

Abstract. World reserves of bauxite are abundant. Domestic reserves are limited and as a consequence the United States must rely on foreign suppliers for over 90 percent of its bauxite. Nationalization of many bauxite mining operations, levying of higher taxes, increased production and transportation costs, and attempts to create a uniform market price combined to place the United States in a vulnerable position. Alumina from kaolin, alunite, anorthosite, and oil shale have-been-or are being evaluated. World bauxite reserves are increasing and attempts to establish a uniform price have failed; therefore, it may be many years before domestic non-bauxite sources of alumina can compete with imported foreign bauxite.

Jan 1, 1980