• Journal of Advanced Marine Engineering and Technology
• /
• v.21 no.3
• /
• pp.311-318
• /
• 1997

In this paper, a controller with monitoring functions is proposed for controlling temperature of an electric furnace system. The controller includes holding and ramp control functions, and the control program for the temperature process monitor of the electric furnace. For this purpose, the implementation and performance of auto tuning algorithms in a computer¬based controller is studied in relation to control of a nonlinear electric furnace system which is characterized with large time delay. The communicator of a control and detection signals, between the controller and the electric furnace is implemented by an I/O data card. Experiments for the practical electric furnace are performed to illustrate the performance of the proposed controller.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.22-25
• /
• 1995

This paper shows adaptive control using RHPC(Receding Horizon Predictive Control) with equality constraint which applied to Electric Furnace. The control strategy includes monotonic weighting (improving transient response) and pre-filtering (enhancing robustness), which is effective on real process. We can observe the performance of RHPC and confirm the practical aspect of RHPC with unmodelled dynamics through the experiment of Electric Furnace. Finally, this paper verifies the feasibility of RHPC to real process.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.1
• /
• pp.23-30
• /
• 2015

The properties of dust collected from electric arc furnace of ferro manganese production units was investigated, and also the metallic manganese was recovered from the dust by aluminothermy process. The ferromanganese dust collected from electric arc furnace contained about 15% of manganese oxide ($Mn_3O_4$) and 9% of carbon as the contaminant, and have a 5um of 50% median diameter and irregular particle shape. The carbon contaminant in the dust could be reduced until about 0.1~0.5% level by roasting in the air at a temperature of 600~900C for 60minutes. The recovery of manganese could not be carried out using only ferromanganese dust from electric arc furnace by aluminothermy process, but the ferromanganese which contained manganese of about 92% and iron of about 5% could be obtained from the mixture of ferromanganese dusts from electric arc furnace and converter. The best mixing condition of dust fixed at electric arc furnace dust / converter dust ratio of 1:9 and 2:8, and the mixing rato of 3:7 or more could not separated the metal and slag from the reactant after aluminothermy reaction.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.393-397
• /
• 2001

The innovatory process, that is the direct separation and recovery of the iron and zinc metals contained in the high temperature exhaust gas generated from the electric arc furnace fer the inn scrap melting and/or the dust treatment, has been proposed. This proposed process consists of the moving coke bed filter that is directly connected to the electric furnace, and the following heavy metal condenser. The exhaust gas passes through the filter and the condenser right after exhausting from the electric furnace. The moving coke bed filter is being controlled at about 1000℃ and collects iron and slag components contained in the high temperature exhaust gas. Heavy metals such as zinc and lead pass through the filter as vapor. Based on the thermodynamic considerations, the iron oxide and the zinc oxide are reduced in the filter. The solution loss reaction rate is comparatively low at about 1000℃ in the coke bed filter by the analysis using the mathematical simulation model. The heavy metal condenser is installed in the position after the coke bed filter, and rapidly cools the gas from about 1000℃ to 450℃ by a full of the cooling medium like the solid ceramic ball in addition to the cooling from the wall. The zinc and lead vapor condense and separate f개m the gas in a liquid state. The investigation of the characteristics of the exhaust gas of the commercial electric arc furnace, the fundamental experiments of the laboratory scale and the bench scale ensured the formation of this proposed process. A small-scale pilot plant examination is carrying out at present to confirm the formation of the process. It is certain that the dust generation of the electric arc furnace is extremely decreased, and it can save the energy consumption of usual dust treatment processes by the realization of this process.

• Journal of the Korean Society of Safety
• /
• v.12 no.2
• /
• pp.80-86
• /
• 1997

In this paper, a temperature controller with monitor function is proposed for the electric furnace system. This controller includes holding and ramp control function, and the control program for the temperature process monitor of the electric furnace. For this purpose, the implementation and performance of auto tuning algorithms in a computer-based controller was studied in relation to the control of nonlinear electric furnace system which is characterized with large delay time. The control program for this controller programmed by c-language. To communicate a control and detection signals, between the controller and the electric furnace is implemented by the I/O data card. We apply the temperature controller to the practical electric furnace. As a result, the proposed controller shows the better status characteristic.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.613-618
• /
• 2002

Steel slag produced in steel making process is divided with electric arc furnace slag and converter slag. Compared with the blast furnace slag, converter slag has the expansibility due to the reaction with water and free CaO. Therefore it is specified in Standard Specification for Concrete in Korea that steel slag aggregate must not be used in concrete. In this study, we treat electric arc furnace slag aggregate(EAFSA) for concrete before and after several aging process to reduce expansibility. The fundamental properties are measured, which are specific gravity, unit weight, abrasion value and immersion expansion ratio, as concrete aggregate. To understand the suitability of EAFSA for concrete, we made the concrete with EAFSA and then determined the strength and the volume change in EAFSA concrete. From the results EAFSA treated with steam aging process has potentiality for concrete aggregate.

• Journal of the Korea Concrete Institute
• /
• v.14 no.4
• /
• pp.597-607
• /
• 2002

Electric arc furnace and converter slag are produced by about 6 millions tons in Korea at 2000 year. But compared with blast furnace slag, those are utilized only in unvalued material like landfill and road construction. There are unstable materials, like free CaO, in electric arc furnace and converter slag at steel-manufacturing process. This might cause volume expansion in concrete, if electric arc furnace and converter slag aggregates were used in concrete. This expansion may reach to crack or collapse of concrete. It is therefore settled by standard specification for concrete that electric arc furnace and converter slag aggregates have not to use in concrete. First of all, volume stability and stabilized process should be solved in electric arc furnace and converter slag aggregate to use in concrete. In this study, 6 types of aging are evaluated for effects of stabilization to reduce the expansion of electric arc furnace and converter slag. h converter slag aggregate, these types of aging are not good for volume stability for concrete aggregate, and even if converter slag aggregate is treated with aging, concrete with it has some problems that strength is reduced with curing days. But in electric arc furnace slag aggregate treated with hotwater and steam aging, the expansion of electric arc furnace slag aggregate is reduced about two times than that of converter slag aggregate, and electric arc furnace slag aggregate concrete has good results in strength compared with control concrete using crushed stone.

• Korean Chemical Engineering Research
• /
• v.59 no.4
• /
• pp.611-625
• /
• 2021

Mg crowns were manufactured using domestic dolomite (Ca·Mg(CO₃)₂) (20~30 mm). In order to manufacture the calcined dolomite (CaO·MgO), (a) electric furnace (950 ℃, 480 min) and (b) microwave furnace (950 ℃, 60 min) processes were used. As a result of XRD analysis, it was analyzed as (a) CaO 56.9 wt%, MgO 43.1 wt% by electric furnace process and (b) CaO 55 wt%, MgO 45 wt% by microwave furnace process. Even when the decarbonation reaction time of dolomite was shortened by 1/8 in microwave furnace process compare with electric furnace process, the calcined dolomite could be produced. The hydration reaction (ASTM C 110) is a standard for the hydration reactivity of calcined dolomite, and the calcined dolomite produced by electric furnace process showed a high hydration reactivity (max temp 79.8 ℃/1.5 minutes). Such hydration reactivity was occurred by only CaO hydration reaction and that was confirmed by XRD analysis. The calcined dolomite produced by microwave furnace process showed low hydration reactivity (max temp 81.7 ℃/19.5 minutes). Such low hydration reactivity was occurred by CaO and MgO hydration reaction due to the hydration reaction of CaO thereafter occurring of the hydration reaction of MgO, and that was confirmed by XRD analysis. The prepared Mg crown were 58.8 g and 74.6 g by electric furnace and microwave furnace processes, respectively, under the reaction conditions of 1,230 ℃, 60 min, 5 × 10^-2 torr by silicothermic reduction.

• Proceedings of the KIEE Conference
• /
• 2005.10b
• /
• pp.573-575
• /
• 2005

In the steel industry, a steel melting electric arc furnace is used to produce both carbon and alloy steels. Steel scrap which is charged into the furnace is heated by means of electric arc between graphite electrodes and the scrap. In this melting process, current is supplied to the furnace through HCC(high current cable) which connect the furnace and transformer. Four HCCs are assigned to each phase in our system to divide the current. Since a sudden cable breaking result in the shutdown of melting process, an aging detection of HCC is very important for both an improvement of productivity and cost reduction. In this paper, the aging of the HCC is estimated by using the current ratio between four HCCs.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.55 no.3
• /
• pp.115-118
• /
• 2006

In the steel industry, a steel melting electric arc furnace is used to produce both carbon and alloy steels. Steel scrap which is charged into the furnace is heated by means of electric arc between graphite electrodes and the scrap. In this melting process, current is supplied to the furnace through HCC(high current cable) which connect the furnace and transformer. Four HCCs are assigned to each phase in our system to divide the current. Since a sudden cable breaking result in the shutdown of melting process, an aging detection of HCC is very important for both an improvement of productivity and cost reduction. In this paper, the aging of the HCC is estimated by using the current ratio between four HCCs.