Metallurgical Furnaces Research Articles

A New Optic Senor for Real-Time Bath Temperature Measurement in a BOF

A robust, non-contact sensor that measures BOF endpoint bath temperature has been developed and evaluated over a large number of industry heats. The optical hardware consists of a radiation collection head and a multi-wavelength detection unit. The radiation collection head aimed at the furnace mouth is used to collect, and thus enhance, the effective radiant energy emitted from the hostile environment adjacent a furnace as well as to reduce spurious radiations from other nearby furnaces. The detection unit separates the collected radiations into spectroscopy and then converts this spectroscopy into digital signals. Finally, the signal information is processed to determine the carbon content of the steel contained in the metallurgical furnace. The Preliminary results after online carbon content sensing are discussed.

An analysis of the efficiency gained with replacement of the traditional lining of bell and chamber metallurgical furnaces by lining made of refractory ceramic fiber

In theory, there exist two methods of replacement of traditional lining made of fireclay insulation articles by lining made of OKB Cerablanket refractory ceramic fiber. The first method consists in production of lining made of OKB Cerablanket rolled material with the material being formed in undulating fashion into sections with height of a wave equal to the thickness of the lining. In the second method, the lining is fabricated from ready-made modular Z-blok sections with integrated anchors made of stainless steel. Sections fabricated from OKB Cerablanket rolled material is arranged in a linear or checkerboard arrangement. The operating life of lining fabricated from refractory fiber is practically unlimited. Anumber of conditions that guarantee long and effective service of the materials must be fulfilled, for example, the furnace temperature must not exceed 1170°C, rate of gas flow must not be greater than 20 – 30 m/sec, and the lining must not be subjected to mechanical loads.

A Novel Optic Senor for Real-Time Metal Analysis in the BOF Steelmaking Process

A fiber optic senor for carbon content measurement of the molten steel in a basic oxygen furnace (BOF) is described. The sensor includes a fiber optic cable for transmission of the optical radiation from the radiation collection head to the multi-wavelength detection unit located in remote area from a furnace. The radiation collection head includes a telephoto lens aimed at the furnace mouth to collect, and thus enhance, the effective radiant energy emitted from the hostile environment adjacent a furnace as well as to reduce spurious radiations from other nearby furnaces. The detection unit based on emission spectroscopy converts the radiations into digital signals and the signal information processed to determine the carbon content of the steel contained in the metallurgical furnace. The Preliminary results after online carbon content sensing are discussed.

Beam tracing in determining the inclination of radiation in complex industrial geometry

In zonal calculations of hightemperature metal� lurgical furnaces—including calculations by the dynamic zonal-point method—the radiant heat� transfer rate between zones is determined on the basis of the inclination of the radiation beams between sur� face zones and volumes. For successful incorporation of zonal calculation within the dynamic zonal-point method in modern hydroaerodynamic simulation programs, see (1-3). Besides the Monte Carlo method, calculation of the inclination of the radiation may be based on pair� wise selection of surface areas and volumes that belong to particular zones (from area to area, from volume to area, and from volume to volume). Calculation results show that, in calculating incli� nations for complex geometry by any method, the greatest challenge is determination of the presence of a screen or obstacle on the path of the beam between two zones. (This process may be known as beam trac� ing.) As shown by calculation, beam tracing often requires additional computation time; this extra time may be one or two orders of magnitude greater than the time for calculation of the inclination.

Archaeomagnetic investigation of a metallurgical furnace in Pisa (Italy)

Abstract An archaeological excavation has been carried out at Pisa (Italy), unearthing an ancient metallurgical workshop. Since archaeological burnt materials provide important records of direction and intensity of the Earth's magnetic field in the past and they can be used to better improve geomagnetic secular variation curves (SVCs), an archaeomagnetic study has been performed. This small copper-alloy furnace presents a circular concave shape covered with a thin layer of mortar, with some traces of heated clay surrounding the feature that confirms the high temperature reached inside it. Archaeological context dating points to the last firing of the furnace between the last quarter of the 13th century and the first quarter of 14th century AD, when then the metallurgical workshop was transformed in a warehouse. Archaeomagnetic sampling has been performed using the modified Thellier method, by collecting several, large and independently oriented aliquots of heated clay, forming the bottom part of the circular wall of the structure. Laboratory treatments have been conducted at the IGG-CNR ARCHEO_LAB (Pisa, Italy) and at St. Maur Palaeomagnetic laboratory (Paris, France). Analytical measurements of the thermo-remanent magnetization index acquired from the samples have been performed using a large cell induction magnetometer for large samples, and the characteristic remanent magnetization (ChRM) has been successfully isolated after an alternate field demagnetization cleaning procedure for each sample. The final mean archaeomagnetic direction has been calculated at sampling site (D = 6.9°; I = 52.8°; N = 9; k = 305; α95 = 2.6°) following the Fisher Statistics, and it exhibits a perfect agreement with some coeval already published directions obtained from Mt. Arso lava flows, these latter being an important anchor point in the preliminary Italian secular variation curve. Comparison with the preliminary Italian SVC, the French SVC and the SCHA.DIF.3K archaeomagnetic regional model have permitted to define an archaeomagnetic absolute age confirming the conventional archaeological age, underlining the importance of this result into the Italian archaeomagnetic data set.

Technology and evolution: a root and branch view of Asian iron from first-millennium bc Sri Lanka to Japanese steel

Evidence for a previously unrecognized pan-Asian metallurgical tradition of linear configuration iron-smelting furnaces is reviewed. The foundation of this technological lineage lies in an evolutionary series of excavated furnaces in Sri Lanka dating from the fourth century bc to the eleventh century ad. Further archaeological, ethnographic and documentary evidence from Burma, Cambodia, Sarawak and Japan demonstrates the spread of linear furnace technology and its association with the production of high-carbon steels, often associated with weapons manufacture. An evolutionary approach is used to argue that a process of memetic inheritance explains a major divergence in Eastern and Western metallurgical development and furnace design.

Quantitative formulation of mechanism of sintering process during creep deformation of refractory concretes

This paper is concerned with quantitative formulation of the mechanism of the sintering process during secondary state creep deformation of refractory concretes. Investigated concretes varied in, both, chemical and mineralogical compositions. The sintering process during secondary state creep within refractory concrete has an isothermal character. Thus, an attempt was made to describe the mentioned process quantitatively. Creep was investigated at three different temperatures: 1200, 1300 and 1400?C. Variations of the microstructure of concrete samples, exposed to constant static pressure and constant temperature during certain time-intervals, were investigated using a scanning electron microscope. Obtained results of the investigation proved that creep resistance is an irreplaceable method when the decision about the best possible type of refractory concrete for application in metallurgical furnaces is required.

Design and automation of a modern reverberatory heat-treatment furnace

This article examines aspects of the design and automation of modern metallurgical furnaces by using a reverberatory furnace for heat-treating tubular semifinished products as an example. The article describes the structure of the furnace control system and automation equipment (controllers, PID-regulators), as well as a system designed for remote monitoring and control of the furnace’s operation.

Production of unroasted briquets based on small lignite semicoke particles from Kansko-Achinsk coal

An efficient production technology for unroasted briquets from lignite semicoke has been developed; the lignite semicoke is derived from Kansko-Achinsk coal. The briquetting conditions are described. In terms of strength and physicochemical properties, the semicoke briquets are suitable for use as residential heating fuel, as fuel for metallurgical shaft furnaces, and also as the reducing agent in ferroalloy production.

Improving lining systems for metallurgical equipment

Results are presented from a project undertaken to improve the systems used to line metallurgical furnaces at the Chelyabinsk Metallurgical Combine. The improvements made reduce the unit consumption of refractories and increase the life of the lining in several pieces of equipment: the main furnace used to make corrosion-resistant steels; the argon-oxygen refining unit; the tundishes of the continuous casters in electric steelmaking shop No. 6; the electric furnaces and vacuum chambers in electric steelmaking shop No. 2, and other equipment.

Archaeometric study on polymetallic remains from the archaeological dig in Lixus (Larache, Morocco) by scanning electron microscopy and metallographic techniques

A study is presented on polymetallic remains from several phases of production, refining and moulding processes from metals recovered in Lixus (bronze 6th and iron 2nd century b.c.). SEM/EDX and metallographic techniques are used in a typographical study comparing chemical and microstructural information so that the hypothesis on metallurgical activity can be verified in a technological context (furnace types and construction materials, fuels, alloys, tools, etc) and the socioeconomic context. A re-casting metallurgical furnace is studied to obtain alloys and proof of their use, for instance from the fuel charge of charcoal and bronze nodules recovered from around the furnace. The set of iron material represents practically the whole process of iron production in an ancient smelting furnace. After cleaning the samples, macroscopic analyses permit to differentiate three kinds of materials from the direct reduction process for iron: cast slags, remains of the ancient smelting furnace wall, and metallic iron product resulting from iron mineral reduction.

Temperature Rise Characteristics of Carbon-Containing Chromite Ore Fines in Microwave Field

To avoid the nonuniform phenomena of heat and mass transfer of metallurgical powdery materials caused by conventional heating method, the temperature rise characteristics of carbon-containing chromite ore fines in the microwave field were investigated using microwave heating in a microwave metallurgical furnace. The experimental results show that the carbon-containing chromite ore fines have better temperature rise characteristics in the microwave field at a frequency of 2.45 GHz. After heated in the microwave field of 10 kW, the temperature of 1 kg carbon-containing chromite ore fines rose up to 1 100 °C in 7 min, at a temperature rise rate of 157. 1 (°C · min−1 · kg−1), whereas the temperature of 1 kg carbon-containing magnetite ore fines rose only up to 1 000 °C in 10 min, at a temperature rise rate of 100 (°C min−1 · kg−1). With increasing carbon-fitting ratios and by adding calcic lime, their heating effects changed regularly.

Study of the influence of current frequency and non-magnetic gap value on the efficiency of Al-alloys stirring in metallurgical furnaces

Study of the influence of current frequency and non-magnetic gap value on the efficiency of Al-alloys stirring in metallurgical furnaces

Use of metallurgical furnaces in recycling

This article examines the potential for recycling household wastes in the converter and blast-furnace processes. A method of performing such recycling in blast furnaces is described.

The metallurgic furnaces at the Curamba Inca site (Peru): a study by Mössbauer spectroscopy and X-ray diffractometry

The Inca site at Curamba is located in the Province of Apurimac in the southern highlands of Peru where, according to some historians, several thousand furnaces used for ore smelting were found. For this work, four samples of burned soil were gathered from these furnaces and classified as Curamba1, Curamba2, Curamba3, and Curamba4, and studied using transmission Mossbauer spectroscopy (TMS) and X-ray diffractometry (XRD). The mineralogical composition of the samples was determined by XRD and the structural sites in the minerals occupied by iron cations were characterized by TMS. Moreover, an attempt was made to determine the maximum temperature reached in these furnaces using the refiring technique of the samples in an oxidizing environment and monitoring the structural modifications at the iron sites by changes in the Mossbauer hyperfine parameters. The TMS results of Curamba2 show that the maximum temperature reached in this furnace was about 900°C, in agreement with the mineralogical composition found by XRD. In the case of Curamba1 and Curamba4 the maximum temperature estimated was about 400°C.

Magnetohydrodynamic siphon for tapping out liquid metals

The evacuation of liquid metals or mattes from metallurgical furnaces presents many operational challenges due to safety issues and the fast destruction of tapping blocks. Particularly, a continuous smelting and converting processes requires continuous tapping out with a precise control of the liquid metal or matte flow. Siphons are used in numerous metallurgical reactors including shaft furnaces for copper concentrate smelting and the Mitsubishi electric furnace. A new technique for the precise tapping out of metals or mattes has been developed. It is based on the apparent change of specific gravity of conducting liquids placed in a cross of a constant electric field and a permanent magnetic field. Additionally, the Lorentz’ force in uniform electric and magnetic fields can be controlled by the magnetic flux and current intensity. This allows for a precise temperature control of the metal or matte. Fluidodynamic and heat transfer modeling, supported by low temperature physical modeling, allowed for the design of a large laboratory scale device. The test results demonstrated the ability for very precise control of temperature, level and flow rate of copper matte tapped out from the furnace.

New generation of thermal imaging systems for thermal monitoring of the lining of metallurgical furnaces

The use of new thermal imaging systems is significantly expanding the possibilities for tracking and analyzing the thermal phenomena which take place in heating furnaces, and it shows that systems can be developed to continuously monitor the condition of these units. Solving this problem will lengthen the service life of heating furnaces, practically eliminate burn-throughs of the lining, and bring about a significant monetary savings.

Reconstruction of Metallurgical Furnaces with the Use of Electrical Heating Units

Reconstruction of Metallurgical Furnaces with the Use of Electrical Heating Units

A reduction radiation sensor for measuring temperature in metallurgical production furnaces

A cooled contact sensor for monitoring the temperature in metallurgical production furnaces is proposed. It does not contain precious metals and is comparable in its metrological characteristics and has better operating characteristics than platinum thermometers.

Technology for recycling industrial wastes in metallurgical furnaces

Technology for recycling industrial wastes in metallurgical furnaces