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By Nicolás Lugo

The electric steel industry has reached a level of maturity in its relative participation in the world’s steel production. As the industry has grown and matured, EAF steel producers have participated in an ever more competitive market. This competition has led to a continuous search for lower cost alternatives for energy and input materials. Over the years, the Electric Steel Furnace community of operators has developed a variety of technological improvements geared to increasing EAF productivity. Operators have emphasized lowering operating costs and improving the quality of steels produced. Depending on market conditions, the EAF operators may run with different goals and priorities. In times of low demand, the goal may be to operate with an emphasis on cost and the goal of maximizing cost effective use of resources. When the market demand is high the goal may be to maximize EAF throughput. The objective of this work is to list some of the EAF operating best practices observed by our team in the electric arc furnace operations around the world. EAF operators can consider and possibly implement these practices depending on the specifics of each EAF operating reality.

Jul 29, 2018

By Grégory Miette

The paper deals with a process that allows the recycling in a cupola of EAF dusts with 18 % Zn. It produces dusts with zinc grade higher than 50 - 55 % and commercial cast iron with less than 200 ppm Zn, 50 ppm Pb, 0.15 % S. The paper focuses mainly on lab tests made with the aim to develop an effective formulation of self reducing - melting pellets. With such a formulation, agglomerates develop a breaking load higher than 125 - 150 kg without any thermal treatment. Zinc and lead are volatilized in the cupola with yields higher than 95 % at 1200 OC, before any melting. Sulphur is transfemed into gas and slag. All these conditions allow to lower zinc, lead and sulphur grades below the cast iron specifications. Results of first bench scale tests performed at Fonderie Piret to validate the process will be presented.

Jan 1, 2002

By J. Kevin Cotchen

The results of "submerged arc" electric furnace processing of a variety of materials is discussed with respect to the process and products, including the characteristics of the products (e.g. TCLP or Toxicity Characteristics Leaching Procedure). The materials melted include slags and wastes containing various metal oxides including copper, tin, lead, zinc, chrome, nickel and other associated elements. The findings of these tests are compared to those reported in the literature for other operations treating similar "wastes".

Jan 1, 1992

By Marco Pasetto

The possibility to re-use marginal materials (by-products) deriving from industrial activities in the construction of road infrastructures, as total or partial substitution of natural aggregates, successfully combines demands for economy and environmental sustainability. The paper presents the results of a laboratory study, conducted at the Experimental Road Laboratory of the University of Padova, to verify the suitability of a particular type of electric arc furnace slag to be recycled in the lithic skeleton of high-performance asphalt mixes (porous asphalt, high modulus mixes, stone mastic asphalt, nonskid surfacings) for road and airport flexible pavements. the process of transformation of iron and steel slag into a product that can be used in road building is described, along with the characterisation of the mixtures, plus an analysis of the results of a wide battery of mechanical-performance tests. This study forms part of wider theoretical ? experimental research being done at the University of Padova in order to improve knowledge of the characteristics of succedaneum materials and check their possible applications in road and airport construction.

Jan 1, 2006

By J. A. Bakken, T. Magnusson, G. Sævarsdottir

This paper describes measurements of current and voltage done on submerged arc furnaces. The aim is to focus on and attempt to separate from one another the electric arc current and the current bypassing the arc through the charge. Toward this goal two measurement campaigns on AC-arcs burning on coke beds are ac-counted for. The first was done on a 150 kVA pilot furnace at SINTEF in Trondheim Norway, and the second one was done on a 48 MVA industrial furnace run by Icelandic Alloys in Iceland. The measurements were compared to simulations employing an advanced MFD arc model. The main results are that a coke bed does not necessarily behave as a linear conductor. However the warmer chemically transformed part of an operating Si-metal or FeSi furnace probably exhibits linear behaviour and passes a considerable fraction of the phase current, perhaps on some operating conditions, as much as 50%.

Jan 1, 2007

By Don Eby

The application of electric arc furnace smelting of lead, antimony, and tin bearing slag from a reverberatory furnace will be discussed. The selection procedure for the 4.0 MVA electric arc furnace in Indianapolis, Indiana is presented. The design criteria for the transformer, electrodes, refractories and associated equipment is presented. The operation of the furnace including chaJ:9ing, bullion tapping, slag tapping, ventilation, slag composition, metal recoveries, and toxic leach results of thra.1 away slag are discussed. Flow charts and the equipment specifications are given.

Jan 1, 1990

By Fred C. Drury

Blasting vibrations have been a concern to those using explosives since as early as 1927. Many criteria have been used to correlate vibration levels with damage to structures. After considering many alternatives, peak particle velocity has become the most commonly used criteria.

Jan 1, 1975

By R. G. Clay, C. F. Seaman

THE mines of The Tennessee Copper Co. are in the Ducktown Basin, in southeastern Tennessee. The ore is a heavy sulphide consisting principally of chalcopyrite, pyrite and pyrrhotite and in places running as high as 05 per cent sulphur and iron. Operating mines are the Burra Burra and Eureka. Development of the Boyd ore body was started in 1940. Late in 1939 the decision was made to change from fuse and cap to all electric blasting and at the same time electric cap lamps were installed to replace carbide. These changes were made to improve the safety and working conditions in the mines. Both the Bureau of Mines and explosives manufacturers recommended electric blasting as a safety measure. Until that time, electric blasting had been used only for shaft sinking and in places where it was absolutely essential for safety. Very few men had had experience in this type of blasting, as the places where it was required were those that also required direct supervision. It was necessary for the mining staff to work out methods, procedure, and equipment to he used. In this they were ably assisted by representatives of the explosives manufacturers. Many mistakes were made and it is the purpose of this paper to describe the original plan and installation, show the major difficulties encountered, the remedies applied, and present the practices now being followed. Comparison of costs of the two methods will also be discussed. About six months were required to make the change and eliminate fuse and cap blasting entirely. The first electric blasting stations were installed in November 1939 and the last fuse was taken underground in May 1940. A very unusual condition forced the use of fuse for a short time in one heading after May, but that will be discussed later. ORIGINAL EQUIPMENT AND INSTALLATION A power line is generally recommended as a source of current where permanent blasting stations are used. The plan worked out for electric blasting was to tap 220-volt alternating-current lines when they were available and use 250-volt direct current from the trolley wire at all other places. A blasting machine would he available at each shaft for places where there were no regular blasting stations and could he used if a regular station should fail. The equipment decided on was No. 16 duplex reinforced lamp cord for lines to within about 50 ft. of the working place and No. 20 lead wire from that point to the shots. An open double-pole, double-throw switch with slate base was put in the circuit, so connected that the down position would close the line to the shots and the up position would connect it to the line from the power contactor. This switch was located in the circuit as close to the blast as was safe (should the shots explode when it was placed in the shooting

Jan 1, 1942

By R. G. Clay, C. F. Seaman

THE mines of The Tennessee Copper Co. are in the Ducktown Basin, in southeastern Tennessee. The ore is a heavy sulphide consisting principally of chalcopyrite, pyrite and pyrrhotite and in places running as high as 95 per cent sulphur and iron. Operating mines are the Burra Burra and Eureka. Development of the Boyd ore body was started in 1940. Late in 1939 the decision was made to change from fuse and cap to all electric blasting and at the same time electric cap lamps were installed to replace carbide. These changes were made to improve the safety and working conditions in the mines. Both the Bureau of Mines and explosives manufacturers recommended electric blasting as a safety measure. Until that time, electric blasting had been used only for shaft sinking and in places where it was absolutely essential for safety. Very few men had had experience in this type of blasting, as the places where it was required were those that also required direct supervision. It was necessary for the mining staff to work out methods, procedure, and equipment to be used. In this they were ably assisted by representatives of the explosives manufacturers. Many mistakes were made and it is the purpose of this paper to describe the original plan and installation, show the major difficulties encountered, the remedies applied, and present the practices now being followed. Comparison of costs of the two methods will also be discussed. About six months were required to make the change and eliminate fuse and cap blasting entirely. The first electric blasting stations were installed in November 1939 and the last fuse was taken underground in May 1940. A very unusual condition forced the use of fuse for a short time in one heading after May, but that will be discussed later. ORIGINAL EQUIPMENT AND INSTALLATION A power line is generally recommended as a source of current where permanent blasting stations are used. The plan worked out for electric blasting was to tap 220-volt alternating-current lines when they were available and use 250-volt direct current from the trolley wire at all other places. A blasting machine would be available at each shaft for places where there were no regular blasting stations and could be used if a regular station should fail. The equipment decided on was No. 16 duplex reinforced lamp cord for lines to within about 50 ft. of the working place and No. 20 lead wire from that point to the shots. An open double-pole, double-throw switch with slate base was put in the circuit, so connected that the down position would close the line to the shots and the up position would connect it to the line from the power contactor. This switch was located in the circuit as close to the blast as was safe (should the shots explode when it was placed in the shooting

Jan 1, 1942

By Alf Holmelid

Until recently the only automatic control of electric parameters in submerged-arc furnaces has been electrode control with electrode current or electrode impendance as controlled variables. Elkem Research and Development Centre has delivered this kind of control for a long time, both stand- alone controllers and control algorithms incorporated in an integrated computer control system. In recent years we have noticed increasing interest in more sophisticated electric control. Results both from pilot-plant experiments and from production furnaces show that proper electric conditions in the furnace are more important to the furnace operation than was assumed earlier. Optimal electric conditions lead to lower power consumption per ton of metal and allow use of cheaper raw materials Besides, power contracts and the market situation lead to more frequent change of load on the furnaces. Therefore it is important to vary the load in a way that allows proper electric conditions to be maintained. Based on this renewed interest in electric control, Elkem Research and Development Centre has carried out a project, starting with analysis of existing electric instrumentation and control algorithms for electrode control, and ending up with an integrated electric control strategy including power-demand control as shown in Figure 1. In this paper we will give a resume of this work and present a new integrated control strategy put into operation for the first time in June 1983. [ ]

Jan 1, 1984

By D. Triantis

This paper presents the results of laboratory experiments for the detection of electric signals from Fiber Reinforced Polymer (FRP) sheet samples which have undergone a temporally increasing loading of bending type up to fracture. Electric signals that were recorded while the sample was subjected to bending are referred from now on as Bending Stimulated Currents (BSC), in order to differentiate them from the relevant signals emitted by materials that suffer uniaxial compressional stress. The latter signals are referenced as Pressure Stimulated Currents (PSC). BSC emitted from FRP sheet samples presented here, were recorded after applying three successive load steps to samples. The increase rate of applied stress was about 0.15kN/s. Initially starting from low load values to higher load values until the FRP sheet reaches at a state just before its failure. The BSC records from FRP samples are compared to equivalent recordings from cement mortar beam and distinguishable differences are discussed.

Jan 1, 2006

By J. G. Asbury

Broadly conceived, the demand for electricity depends upon three sets of variables: (i) the growths of the many individual demands for energy services; (ii) the competitiveness of electrically driven technologies in meeting these demands; and (iii) the energy-conversion efficiencies of installed electrical technologies. The first set of variables establishes the size of the potential market; the second, the market penetration of electrical equipment; and the third, the quantity of electricity required to operate the equipment. All forecasts of electricity consumption ultimately depend upon inferred or assumed relationships to describe the future behavior of these variables. This partitioning of the demand-forecasting problem is conceptually useful and will guide the discussion presented in this paper. However, it is also something of an oversimplification. Examined in more detail, the electricity fore-casting problem is exceedingly complex. The variables mentioned above are, in turn, found to depend upon more fundamental sets of demographic technological, resource, and policy variables. The demand projections developed by the major forecasting services are usually developed in terms of these underlying variables, which themselves must be independently forecast.

Jan 1, 1985

By Richard N. Snyder

In this system for connecting blasting caps to the initiation source, the need for a redundant design structure provides more reliable method of explosive initiation. This is accomplished by using a complete system starting at the blasting control, through the initiation line structure through the initiation line and connecting blocks to the blasting cap. The connecting structure between the initiation device and the blasting caps may be connecting blocks or other means.

Jan 1, 1995

By George Haworth

ELECTRICAL illumination of shafts, stations, and haulageways has been successfully practiced for many years, but its use in drifts and stopes where mining operations are carried on has- been limited. The large underground drifts of the Tri-State field present a lighting problem that is not satisfactorily solved by the use of the carbide lamp. It has, for some time, been the policy of the Anna Beaver mine to provide ample lighting throughout the underground haulage drifts and working faces. This has, in the

Jan 6, 1928

By W. P. Lass

(San Francisco Meeting, September, 1015) THE gold precipitate from the zinc-dust presses in the cyanide plant of the Alaska-Treadwell Gold Mining Co.; Treadwell, Alaska, is treated, in the refinery adjoining, by the Tavener or lead-smelting method. About. 3 or 4 tons of this precipitate are produced monthly having a gold assay value of $40,000 to $60,000 per ton. It was formerly the practice to treat the by-products from this process, consisting of 2 tons of slag, 300 lb. of matte, 500 lb. of refinery refuse, flue dust, etc., in a 24-in. water-jacketed blast furnace. This' practice was discontinued in the summer of 1914 by reason of the difficulty of keeping the lead-well open when treating a high-grade lead product; of preventing the loss of gold in the flue dust; and of avoiding injury to the general health of the refinery operators; a plain single-phase electric furnace was substituted for the blast furnace. The furnace was constructed from an old steel acid drum by cutting off the top and introducing a cable, made from strands of bare copper wire, through the bottom and spreading the strands out fan-shaped on the inside of the drum. Powdered graphite, obtained by grinding up old crucibles, mixed with 10 per cent. cement, was tamped wet into the bottom of the drum, around and completely covering the copper wires. The graphite was carried up to the bottom of the furnace, or lead-well, and acted as the lower electrode. The sides were built up of ordinary firebrick forming a melting chamber 14 in. in diameter by 20 in. high.

Jan 7, 1915

By W. P. Lass

Discussion of the paper of W. P. LASS, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 103, July, 1915, pp. 1443 to 1447. ROBERT M. KEENEY, Somersville, Conn. (communication to the Secretary *).-There is not only a possibility of improvement in present methods of treatment of the byproducts of refining in the cyanide plant by the use of the electric furnace, but also in melting and refining of gold precipitate. This interesting paper by Mr. Lass shows an electric furnace in successful operation in a large plant for the treatment of by-products. Electric melting of cyanide precipitate is a cheaper form of treatment in many cases than any of the combustion methods now used because of the high cost of oil, coke or coal in many camps, while on the other hand electric power may be had cheaply, especially in a place where there is possibility of development of high-head hydro-electric plants for power purposes. Also, if the oil-fired tilting furnace is used for direct melting of the precipitate, as is the case at many small mills, a great saving in cost is made by the use of the electric furnace because of the high crucible cost in melting with the tilting furnace. A study of this paper indicates the cost of the operation approximately. Consider all the fluxes to be turned in as byproducts and coke at $18 per ton.

Jan 12, 1915

By A. Golpaygan

Application of Computational Fluid Dynamics (CFD) modeling for simulation of fluid flow and combustion in industrial scale electric furnace is presented. Poor combustion efficiency, roof and/or side wall overheating, carry over to off-gas system and non-ideal radiative heat transfer to processes or cooling systems have been common limiting factors causing inadequate process performance of the furnace, operational problems, and safety hazards. This paper describes how CFD analysis can be used to obtain a better understanding of commonly observed problems associated with freeboard combustion. Examples are presented to describe using combustion CFD modeling to understand requirements to diagnose a problem with furnace design including required freeboard volume or possible roof/side wall overheating.

Jan 1, 2011

By I. A. Cameron, F. Ham, R. Sriram

"Planned increases in electric furnace productivity and higher matte temperatures needed for the Sudbury Smelter's S02 Abatement Plan, require an improved matte tap hole. Since startup in 1978, the matte tap holes have been incrementally improved by the addition of copper cooling blocks around the refractory tap blocks. These improvements provided a tap block life of about 100 taps per campaign.In July 1993, a prototype matte taphole was installed in Number 2 Electric Furnace to develop the technology to increase tap hole service life. The design was based on a heat transfer model of the tapping process to determine candidate refractory materials and cooler arrangements. The prototype tap hole features increased copper cooling, high conductivity refractories and extensive instrumentation. Eight trial campaigns are reviewed outlining the performance of silicon carbide and graphite refractories and typical heat loads during tapping.IntroductionFalconbridge Limited operates two 36 MYA, 6 electrode submerged arc electric furnaces in Falconbridge, Ontario. The furnaces, commissioned in 1978, smelt a partially roasted nickel-copper calcine, to produce matte for converting and slag for discard. Additional details of the smelter are available in the literature(1-4).Each furnace was equipped with two matte tap holes located in the furnace end wall. Early in the campaign, matte tap holes were identified as a weak area in the furnace which could be improved. From 1981 to 1987, incremental improvements were made to the design by the addition of water cooled copper blocks. In 1993, a prototype matte tap hole was designed and installed in Number 2 electric furnace to develop the technology to increase tap hole service life. Improved service life is required to meet planned increases in electric fWl1ace productivity and the higher matte temperature needed for the smelter's S02 Abatement Plan.This paper reviews matte tap hole development since 1978; outlines the prototype matte tap hole design, refractory selection and installation; and details the performance of the prototype tap hole during the first eight campaigns."

Jan 1, 1995

By Paykan Safe

?? Background ?? WorleyParsons Gas Cleaning ?? PT Inco Smelter ?? Process Design Considerations ?? Furnace Control and Combustion ?? Combustion Chamber ?? Spray Chamber ?? Draft Control ?? Baghouse ?? Secondary Ventilation ?? ID Fan ?? Dust Handling Equipment ?? Project Execution ?? Heat Recovery ?? Conclusion ?? WorleyParsons Gas Cleaning ? Irving, TX ?? Formerly Gas Cleaning Technologies ?? Acquired by WorleyParsons in 2005 and now part of a global EPCM company ?? 14 years experience in off-gas system design for ferrous and non-ferrous facilities worldwide

May 1, 2008

JESSE L. JONES, ? Pittsburgh, Pa. (written discussion?).-From a commercial standpoint, the most important characteristic of the electric furnace is the ease with which it lends itself to intensive production. The melting of non-ferrous metals, as usually clone in crucible, open-flame, reverberatory, and similar furnaces, has certain disadvantages which are absent in the electric furnace, viz.:

Jan 4, 1919