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By R. F. Evans, J. M. Avert

Much has been written of the glamour of magnesium from sea water, the Aladdin-like creation of a huge magnesium plant in the Nevada desert using cheap hydroelectric power from Boulder Dam; the marvels of the Hansgirg process for the electrothermal reduction of magnesium oxide by carbon, and the ferrosilicon process for producing magnesium from dolomite. This is the story of the production of magnesium by the electrolytic process, using steam-electric power supplied by a public utility, in a plant at Painesville, Ohio, 30 miles east of Cleveland on the shore of Lake Erie. The story is not without interest, since it involves several unique developments that provide the answer to a question frequently asked: How is it possible to produce magnesium metal economically at such a location as Painesville, Ohio? Basically, the answer lies in making use of facilities already in existence for the production of soda ash, which makes it possible to manufacture magnesium chloride, the principal raw material, cheaply enough to offset the high cost of electric power. To this is coupled the successful conversion of by-product chlorine into a product required for the war program. The source of magnesium for this opera- tion is the enormous surface deposit of high-grade dolomite in the region south of Toledo, within reasonable freight haul of Painesville. This same geological stratum underlies the Painesville plant, but unfortunately at a depth of about 3000 ft.— apparently too great a depth to permit underground mining to compete with the delivered cost of rock from surface quarries in other areas. The cost of dolomite obviously is an important factor, since the rock contains only some 12 per cent magnesium (20 per cent MgO) so that one dollar on the cost of stone means more than $8 in terms of its magnesium content, and more than that in terms of recoverable magnesium metal. Production of Magnesia from Dolomite In the summer of 1941, the Diamond Alkali Co. was well along with construction of a plant intended for the commercial production of refractory and other grades of magnesia from dolomite. The process to be used was designed to make maximum economic advantage of existing plant and operations by tying the production of magnesia in with the manufacture of soda ash in such a way as to make use of the lime [CaO)., value of calcined dolomite. The process finally adopted after a lengthy research and development program has much in common with the old Clerc-Nihoul process, but includes certain innovations found to be necessary or advantageous. Essentially, the process is based upon the following series of reactions:

Jan 1, 1949

By E. Krystad, G. Tranell

"The kinetics of boron removal from liquid silicon during slag refining, as a process step in the production of solar grade silicon, has been investigated by means of small scale mass transfer experimental series at 1600°C, using a graphite crucible. The slags were SiO2-CaO based, with or without addition of approx. 19 wt% MgO. Experiments were carried out at slag-metal ratios of 1 or 2, where the silicon initially contained approx. 250 ppm boron. The metal-slag mass transfer coefficients for boron were found to be in the order of 1-3 · 10-6 m/s and were largely influenced by slag composition. The mass transfer rate was higher for the MgO-containing slag than the slags without MgO. The final equilibrium distribution of boron between metal and slag, LB, was determined to be in the order of 2.3-3.3.I. INTRODUCTIONRecent years have seen a race in industry and research aimed at obtaining a reliable metallurgical route for production of silicon for solar cells (SoG-Si) from metallurgical grade (MG) silicon. Metallurgical routes can successfully challenge the traditional chemical routes for production of SoG-Si if they generate metal of sufficient purity while being less expensive in terms of production cost and energy consumption. Efficient removal of boron is one of the greatest obstacles in the refining of silicon by a metallurgical route, because the segregation coefficient of boron in silicon makes directional solidification unfeasible; in addition, the vapour pressure of boron is not high enough for removal by vacuum refining. However, the thermodynamic properties of boron makes removal from silicon by oxidation possible, and thus the process of slag refining of silicon has been receiving increasing attention as a method for boron removal."

Jan 1, 2012

By Dominic T. Jordan, Quinn G. Reynolds, Christopher J. Hockaday, Ian J. Barker

A direct-current (DC) plasma arc furnace is a type of electric furnace used for metallurgical operations. The successful operation of DC furnaces depends to a large extent on gaining a fundamental understanding of the arc phenomenon itself, and ensuring its presence in the furnace at all times. A method for detection of the presence of the arc in a DC circuit is presented, along with discussion of why this may be of value for certain modes of furnace operation such as brush-arc. The theoretical development of the method is presented along with supporting experimental work conducted on large-scale pilot-plant facilities.

Jan 1, 2014

By M. R. Yenchek

The Bureau of Mines conducted research to determine the relationship between cur-rent load and temperature rises in coal mine trailing cables. Six low-voltage, unshielded, portable power cables were continuously and intermittently loaded with direct current of various magnitudes. Temperature rises within and on the cables were measured with thermocouples, and the data were recorded with a computer. Thermal time constants were calculated, which fixed the periods of the duty-cycle tests. Relationships between average temperature at the conductor-insulation interface and current load were established. The steady-state and intermittent currents that produce a 90° C average conductor-insulation temperature were then determined. Comparisons with Insulated Cable Engineers Association (ICE A) steady-state ratings revealed that 10 to 25 pct more current than recommended ICEA ampacities is required to reach rated insulation temperature. Examination of the maximum intermittent temperatures attained showed that autoignition of coal dust and burn injuries to personnel handling the cable would not be concerns if the temperature at the conductor-insulation interface averaged 90° C.

Jan 1, 1988

Jan 1, 1884

By D. W. Butner

The blast -hole method for drilling and breaking ground is not new to the mining industry . For several years it has been used rather extensively in Canada , particularly in the gold mines , where it was first developed and where the major advances in the technique as applied to present - day mining problems have been made . At present , 40 mines in Canada and the United States are using the method in one form or another , and from all indications its use will increase in the future . In two California mines , blast -hole diamond drilling is now used for a part of or for all stoping operations , and in one of these it is used to some extent in development work . At the Mountain Copper Co.'s Hornet mine in Shasta County, about 50 percent of the pyritic sulfide ore produced is mined by the blast - hole method , and the U. S. Vanadium Corp. mines 80 percent of the ore produced at its Pine Creek tungsten mine in Inyo County by this method . At Pine Creek , long -hole drilling and blasting is used for mining pillars also , and in pre - stoping development . The blast -hole diamond - drilling method is not applicable to all types of ore bodies . A third property in California , the El Dorado Limestone Company , El Dorado County, tried the method for several months in 1943 and 1944 , but , owing to certain factors that greatly increased mining cost , the company soon returned to conventional mining methods .

Feb 1, 1948

By P Walker, I Crnkovic, D Bennett

The Phu Kham deposit represents a copper-gold porphyry system, with mineralisation present in skarn, stockwork and disseminated styles. Significant folding and alteration events have created a complex heterogeneous mineralogy horizon. Weathering and water table contact have created a leached zone, overlying transition zones with supergene chalcocite- dominant secondary copper mineralisation and clay-rich gangue. Primary ore copper mineralisation is mainly chalcopyrite with minor bornite. The major challenges to the copper-gold flotation process are a wide size distribution of chalcopyrite mineralisation and poor primary grind liberation, a high pyrite content in skarn ore requiring aggressive pyrite depression conditions, clay-rich gangue and non-sulfide copper mineralisation in weathered zones, and a significant association of gold with pyrite.The Phu Kham concentrator has been developed as a conventional semi-autogenous grinding (SAG) and ball milling circuit followed by selective rougher flotation, regrinding and cleaner flotation to produce a copper concentrate containing payable gold and silver values. The concentrator flow sheet design offered a capital efficient compromise between high copper recovery bulk sulfide flotation with large cleaning capacity, and lower recovery copper selective rougher flotation to ensure concentrate specification of 24 per cent copper grade could be achieved. This paper will examine and discuss concentrator flow sheet development, including projects implemented since commissioning to improve copper recovery, and future projects designed to maintain and enhance copper in concentrate production with decreasing copper grade and increasing pyrite content of ore feed, and increasing hardness of primary ore.CITATION:Bennett, D, Crnkovic, I and Walker, P, 2012. Recent process developments at the Phu Kham Copper-Gold Concentrator, Laos, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 257-272 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Fred D. DeVaney

DURING the past few years a radically new process for the magnetic roasting of iron ores has been investigated and developed by Pickands Mather & Co. and the Erie Mining Co. in the Erie laboratory at Hibbing, Minn. This process, originally devised by Dr. P. H. Royster of Washington, D. C., involves the use of a roasting technique quite different from older methods. It has now been demonstrated that iron-bearing materials can be roasted as effectively as by any previously known method, and at a much lower cost. The increasing shortage of highgrade iron ores in this country has accelerated the search for new methods that would permit low grade materials to be utilized. The concept of magnetically roasting low grade nonmagnetic ores such as the oxidized taconites and then separating such material magnetically has always had considerable appeal. The magnetic concentration idea is attractive because of the sharpness of the separations and cheapness of the method. Heretofore, however, the equipment and the processes available for the magnetizing-roasting -step have left much to be desired. The customary equipment available for reduction roasting has been: 1-multiple hearth furnaces, 2-rotary kilns, and 3-shaft type kilns. In addition, it is understood that some work has been done in magnetically roasting fine ores by a process using the FluoSolids principle, but little information on this process is available. The multiple hearth kiln has been used the most but first costs and operating costs have been high because of low capacity, high maintenance, and poor gas utilization. Magnetic roasting can be done in a rotary kiln, but the radiation losses are high and the conversion to magnetite is usually unsatisfactory because of poor contact between the gases and the solids. Of the shaft-type furnaces, probably the most efficient yet developed is that designed by E. W. Davis of the Minnesota Mines Experiment Station. This furnace was operated at Cooley, Minn., during 1934-1937 but was abandoned in 1937 because the operation was uneconomic. Heretofore the basic concept behind most magnetic roasting processes has been the idea of heating iron ore to a temperature of 800° to 1100 °F in a strong reducing atmosphere, preferably either carbon monoxide or hydrogen. Temperatures under 800°F were undesirable since excessive roasting time was required. Temperatures over 1100°F were avoided because of the danger of converting part of the iron to ferrous oxide which is nonmagnetic. In the new roasting process, the operation is carried on in a shaft furnace using a controlled atmosphere containing a low percentage of reducing gas. The temperature in the roasting zone is considerably higher than with the usual reducing gas and this speeds up the reduction time. Portions of the spent furnace gases are cooled and recirculated and this together with the good contact between ore and gas makes for high reducing gas utilization. High heat economy is secured by recuperating heat from the roasted ore by passing the cold reducing gases countercurrent to flow of ore. The heat transfer principle is similar to that employed in a pebble stove and to that used in the Erie Mining Co. furnace at Aurora, Minn., for pelletizing fine magnetite concentrates derived from taconite. The theory of controlled atmosphere during the roasting operation can best be appreciated by inspecting the equilibrium diagram of the Fe-C-O system shown in Fig. 1. An inspection of this diagram shows that in certain areas magnetite, Fe3O4, is the only stable form of iron. A further inspection of this table shows that if the proper ratio is maintained between carbon dioxide to carbon monoxide, such a gas will be reducing with respect to hematite, Fe2O3, and will be oxidizing with respect to both ferrous oxide, FeO, and iron, Fe. It should be kept in mind that the formation of ferrous oxide in a roasting operation is harmful, since this oxide is nonmagnetic; if it forms in any quantity, it will cause substantial loss of iron in the ensuing magnetic separation step. If a ratio of approximately three parts carbon dioxide to one of carbon monoxide is maintained, the resulting operation can be carried on at a relatively high temperature without fear of over-reduction. Specifically, most of the tests in the Erie furnace have been made at a temperature of 1500° to 1600°F, with an entrant gas containing approximately 5 pct carbon monoxide and 15 pct carbon dioxide, with the remainder largely nitrogen. It should be remembered that the ratios of carbon monoxide to carbon dioxide shown in Fig. 1 hold even though the bulk of the gas is an inert gas such as nitrogen. It may surprise many to learn that a gas containing as low as 3 pct carbon monoxide, and 12 pct carbon dioxide with the remainder nitrogen is an extremely effective reducing gas in the 1000° to 1600°F temperature range. The reducing gas is not limited to carbon monoxide, and mixtures of hydrogen and carbon monoxide may be used effectively, provided that a similar ratio is maintained between the reducing gases and carbon dioxide and water vapor. For a more detailed explanation of the theory involved, the reader is referred to U. S. patents 2,528,552 and 2,528,553. From a safety standpoint, the weak reducing gas used in the furnace offers an advantage. Its composition is such that it is well below the limits of explosion should air enter a hot furnace. This condition is not true with the usual reducing furnace, in which a gas rich in carbon monoxide or hydrogen is used. The general furnace design and method of operation may best be understood by an inspection of

Jan 1, 1952

By J. I. Jr. Moore

Many articles have been written about the various operations of Britannia mines and mill, as well as treatises on the geology and ore deposits. A partial list of these papers is given below. Most of these papers have covered well the history of Britannia, and have included a thorough discussion of the geology and ore deposits; therefore, in this paper, no account of these subjects. is necessary. However, a short description of the ore deposits will be given as an aid to a clear understanding of the descriptions of the various mining methods. The Ore Deposits The ore deposits at Britannia occur along a shear zone and are five in number, named for the claims in which they lie, as follows: Jane, Bluff, Fairview, Empress, and Victoria. Each of these deposits is called a mine, as they are separated by 500 to 1,000 feet of barren ground. The Jane mine, although the first producer of the Britannia group, has not been in operation for a number of years. The deposit is a silicified replacement in sediments; with very little evidence of shearing. The Bluff deposit is a highly silicified replacement in porphyry, massive and irregular, very hard in the upper 600 feet with practically no shearing, and softer within chlorite schist in its lower 1,000 feet . The Fairview deposit consists of a series of twelve distinct veins or lodes, rather lenticular in shape, and occasionally merging.

Jan 1, 1928

By S. Pal, A. K. Lahiri

Most of the compounds present in slag are surface active. This gives rise to foaminess of slag. The foam life and foaming index are normally determined by the draining rate of slag through the plateau border, so the foaming index is directly proportional to slag viscosity and inversely proportional to slag density and bubble diameter. When a small amount of a strong surface active compound like P2O5or Cr2O3is present in slag, however, the foam life increases significantly and the above relationship is not obeyed. The strong surface active compounds reduce the draining rate from the film between the adjacent bubbles so the film draining controls the life of the foam. The thickness of the film, Marangoni force, viscosity of the slag, and diffusion of surface active compounds determine the film draining rate. The interplay of these factors leads to very low or high film draining rates and affects the film and foam stability significantly. Keywords: slag, foam, foaming index, film draining

Jan 1, 2004

By M J. Noy

The automated measurement of rock fragmentation particle size distribution in the muck during muck excavation has been developing over the last 16 years. The introduction of stereo camera imaging of the muck has provided improved automated particle segmentation for image-based measurement algorithms. Recently, a new vision system processing algorithm has been developed. The inclusion of 2D texture in the analysis has provided a significant improvement in the definition of the finer size fractions, which has resulted in the automated analysis no longer requiring calibration.The previous stereo vision system algorithm required analysis calibration to account for poor ‘small particle’ definition in the 3D surface profile. This was because of the depth perception limitations of the stereo camera system at greater than 8 m. The new algorithm has been implemented on a number of shovel-installed vision systems, and the algorithm’s performance in automated analysis has been assessed against a diligent manual analysis of the same fragmentation images. The new algorithm provides improved distribution resolution and accuracy.CITATION:Noy, M J, 2015. Evaluation of a new vision system algorithm for automated fragmentation measurement from a shovel, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 721–726 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By R. P. Vinson

The Bureau of Mines examined the effects of high humidity and water droplets on the GCA Corp. real-time aerosol monitor (RAM--l). which uses a lO4mm cyclone preseparator. Tests were conducted both in a laboratory and in a full-scale model mine entry. The laboratory tests were conducted in a test chamber saturated with moisture and water droplets. Under these extreme conditions. the RAM-I responded by indicating dust concentrations of 1-1/2 to 2 mg/m3? although the air was dust free. Within the first 2 h of each test. water accumulated in the cyclone and affected the cyclone particle separation characteristics. resulting in readings of 3 to 4 mg/m3. In addition. condensation formed inside the RAM-I case and affected the liquid crystal display (LCD). However. the full-scale mine entry tests revealed that the RAM-I can function ac-ceptably in an atmosphere of water vapor and water droplets similar to the most severe conditions found in an underground mine.

Jan 1, 1984

By V. Tathavadkar

Worldwide TiO2is extracted from natural ilmenite, rutile, and anatase minerals via the sulphateand chloride processes. The sulphate process generates large volumes of less toxic wastes, whereas the chloride process, including the ilmenite-chloride process of DuPont, yields much lower volume of wastes, which are highly toxic and hazardous. The treatment and disposal of such hazardous chloride wastes is both expensive and difficult in terms of long-term monitoring. Besides the waste management and disposal, there is also a shortage of high-grade titanium dioxide minerals in nature, which consequently yields much larger tonnages of sulphate and chloride wastes. In the present investigation we report the results of an alternative titaniferous mineral beneficiation process based on soda ash roasting of minerals. Compared to the conventional processes for beneficiation of TiO2- ores, the alkali roasting of titaniferous offers several advantages including the zero process wastes. In the soda ash roasting process, the mineral is mixed with sodium carbonate and heated above 1023 K in air. The oxidative roasting of ores yields several complex alkali compounds, some of which produce a liquid mixture above 1123 K. In this paper, we have attempted to characterize the composition and physical chemistry of alkali-rich liquid phase. The phase equilibria in the Ti-(M:Fe)-Na-O system are evaluated and compared with the phases formed as a result of roasting reaction. The experimental results revealed that the composition of complex alkali liquid at the reaction interface plays an important role in determining the transport of O2-ions and decomposition of ilmenite. The roles of the crystal structure of mineral phases and their energetics are also emphasized in controlling their decomposition during alkali roasting. The presence of molten alkali in controlling the partitioning of water-soluble alkali salts and insoluble sodium titanate is also explained. Keywords: ilmenite, anatase, alkali roasting, phase equilibria.

Jan 1, 2004

By Bo Liang, Hongmin Zhu, Kai Huang, Shafiq Alam

A new approach of recovering platinum and palladium from electronic wastes by hydrochloric acid leaching followed by selective adsorption on low-cost and environmentally benign biomass sorbent prepared from easily available agriculture waste is suggested. The obtained adsorbents were prepared by a combination of chemical modification and hydrothermal carbonization process with (NH4)2C2O4. It was found that the maximum adsorption capacity of hydrothermal carbonized garlic peel for Pt( ) and Pd( ) was 1.64 and 0.42 mol/kg respectively. The Langmuir adsorption isotherm was applied to describe the adsorption process. Kinetics of the Pt( ) and Pd( ) ions adsorption was found to follow pseudo-second-order rate equation. The adsorbents were examined by scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). Based on the characterization results, a possible mechanism of Pt( ) and Pd( ) ions adsorption with the hydrothermal carbonized garlic peel was proposed. This study provides a promising adsorbent with efficient adsorption property for platinum and palladium recovery from the leach solution of electronic wastes.

Jan 1, 2016

By AIME AIME

A discussion of the Papers by Prof. H. Hubert, Liege, Belgium ; Mr. Tom Westgarth, Middlesbrough, England ; and Mr. K. Reinhardt, Dortmund, Germany, presented at the London Meeting, July, 1906, and printed in Bi-Monthly Bulletin, No. 12, November, 1906; pp. 910 to 930, 971 to 987, 1037 to 1163. MR. ADOLPH GREINER, Seraing, Belgium :-I have nothing special to add to Professor Hubert's paper except to say that there are some little things that it would be well to have cor-rected when the paper comes to be published. In dealing with the thermal efficiency of the engine, you will find that the 29.84 per cent was a very high one. Professor Hubert has forgotten those engines built under the Cockerill type, but he has referred to them in Appendix II. At our works at Cockerill we have built 63 engines, giving 63,000 h.p., and the other companies who have received licenses have built 113 engines, making 103,000 h.p., and aggregating 176 engines and 166,000 h.p. Eight years ago I had the pleasure of giving to the Institute the results obtained up to that time. Since then a good many engines have been constructed. In 1898 I thought a blast-furnace producing 100 tons of pig iron would allow 3,000 h.p. Professor Witz and Professor Hubert show that with the same production of pig the new engines take 3,800 h.p. out of the gas. At present at Cockerill we make 700 to 800 tons of pig iron per day, and we hope to have 26,000 h.p; in a few years. At present we have only half of that in gas-engines, but we hope to have in five or six years all the gas out of these furnaces to the number of 25,000 or 26,000 h.p. MR. Tom WESTGARTH, Middlesbrough, England:-My contribution is not a paper in the ordinary sense of the word, because I am sure you will agree with me that what I have written is only supplementary to the other two papers. The notes are schedules of the larger-size gas-engines built by the engine-makers, of 500 h.p. and upwards. If you look at the schedules you will find that in England gas-engines have be-

Jan 1, 1907

By Sandin Phillipson

During the course of ground control evaluations conducted by the Mine Safety and Health Administration's Roof Control Division, a number of surface and underground coal mines were visited that exhibited instances of ground failure associated with joints. The evaluations were conducted over a broad geographic area, including the Appalachian Basin from Pennsylvania to Tennessee, and they documented that joints occur in a wide variety of mining conditions and exhibit a wide variety of characteristics. Despite minor local variability in orientations, the joints fit into a cohesive pattern when evaluated on a regional scale in context with the system of thrust faults that define the Alleghany Front. Joints documented for this study, together with joints in sandstone and coal and the trends of drag folds compiled from other studies, were plotted on regional maps using GIS software. The trends of joints, including those that could be described colloquially as "hill seams," were not only parallel to regional fault systems and local trends of drag folds, but were also parallel to the regional patterns of previously mapped joints in sandstone and coal. These observations indicate that the features referred to informally as "hill seams" are in fact joints formed in response to tectonic processes associated with regional deformation of the Cumberland-Allegheny Plateau. The 286-266 million-year-old age of regional deformation significantly pre-dates the time when the Cumberland-Allegheny Plateau was subjected to deeply incised stream valley erosion, which began 25 million years ago. This challenges an existing interpretation that "hill seams" represent local ·stress relief joints that formed when stream valley erosion removed confinement and allowed tensile failure of the rock. Although relaxation of confining stress can reasonably be expected to occur near outcrop, observations indicate that this results in the dilation of existing joints. This paper presents instances of ground failure associated with joints, discusses methods of mitigation, and recommends that the term "hill seam" be abandoned in technical communication because it simply refers to a kind of joint that may exhibit certain weathering and aperture characteristics.

Jan 1, 2010

By G. E. Rencken, J. H. Potgieter, A. Narain, J. Smith

To conserve fresh water resources and comply with environmental regulations, DRDGOLD, a South African gold producer re-treating surface tailings, has transitioned to a fully closed water circulation system. Consequently, the accumulation of contaminants, as well as addition of reagents, has led to changes in water composition that have compromised leach performance and overall gold recovery. A two-sample t-test confirmed a significant difference in gold recoveries between the use of Rand Water, which was used as a benchmark, and untreated process water. Atomic absorption analysis of ERGO’s process water, confirmed the presence of iron, nickel, zinc, and manganese. A study of the effect of the identified contaminants on gold recovery showed that iron, nickel, and zinc have the largest negative effect on gold recovery, with iron and nickel being more detrimental than zinc. Sulphates were shown to have a possible passivation effect, which also influenced gold recoveries, although to a lesser extent than the heavy metals. Calcium, when present in excess, had a positive influence on gold recovery indicating the possible formation of a calcium aurocyanide complex. Lime softening successfully reduced the heavy metal and sulphate concentrations, and the gold recoveries obtained with the treated process water were similar to those as achieved with Rand Water.

Jul 1, 2021

By Raymond B. Ladoo

Silica , or silicon dioxide , ( Si0, ) , occurs in a free state chiefly as quartz , but hydrous silica ( amorphous silica carrying a variable amount of combined water , 2 to 13 per cent ) , occurs as opal , flint , diatomaceous earth , tripoli and so on . Quartz is found in many forms , the most important of which are ; As vein quartz; quartzite ; sandstone ; silica sand and gravel ; as crystals or crystalline grains , masses or aggregates in igneous rocks such as granites , dicrites and pegmatites . Commercially silica is used in many ways , but ordinary uses of sand and gravel are so well known that they will not be considered here .

Jan 1, 1922

By James Douglas

As the operation of light railroads is important to the mining industry, the following statistics of the Arizona Southeastern Railroad may be of interest. When the traffic of the Bisbee copper-mines reached 20,000 tons per year the necessity of better transportation than that afforded by eighteen- and twenty-horse and mule teams became imperative on the score of both cheapness and convenience. Before deciding on the construction of a railroad, the Copper Queen Company made a thorough experiment in transportation

Jan 1, 1899

By Pedro Jorge Walburga Keglevich de Buzin

The steel production in mini mills generates several process residues, among them the electric arc furnace dust (EAFD). This residue has as main elements Fe, O, and Zn, being classified as hazardous by the presence of Pb and Cd. In recent years, a rise in the chlorine content of this residue was observed, motivated by the increased use of scrap with impurities bearing this element. In this work, a qualitative assessment of the presence of chlorine in the electric steelmaking process is made. Complementing it, theoretical considerations based on the computational thermodynamics tool FactSage show the effects of the chlorine on the mineral species in EAFD and on gaseous species in the gas phase (HCl and Cl2). For this study, PVC polymer was used as the chlorine carrier substance which contaminates the EAF charge; presence of other minor elements in the system such as K, Na and Pb were also considered.

Aug 7, 2018