Carbothermal reduction of mill scales formed on steel billets during continuous casting

A billet is a bar made from crude steel which surface contains scales which are rich in iron oxides. This study presents the carbothermal reduction of the scales formed in steel billets. The process included the reaction of the iron oxides contents with carbon (in ratio 5:1) and annealing in a tubular furnace under argon atmosphere. The occurred reactions are discussed using thermodynamic calculations and thermal analysis which indicate a three-stage reduction process Fe3O4 ➔ FeO ➔ Fe3C ➔α-Fe with intermediate reactions at the interval temperature 960 and 1300 °C. The X-ray diffraction confirms the reduction to α-Fe with minor presence of unreacted C, magnetite and wustite. Mössbauer spectroscopy analysis was performed at room temperature where a typical sextet corresponding to the dominant α-Fe is shown as well as wustite, magnetite and cementite to a lesser extent. The magnetization measurements confirm the ferromagnetic state corresponding to the α-Fe.

Investigation on the Chemical and Thermal Behavior of Recycling Agglomerates from EAF by-Products

In addition to the blast furnace converter route, electric steel production in the electric arc furnace (EAF) is one of the two main production routes for crude steel. In 2019, the global share of crude steel produced via the electric steel route was 28%, which in numbers is 517 million metric tons of crude steel. The production and processing of steel leads to the output of a variety of by-products, such as dusts, fines, sludges and scales. At the moment, 10–67% of these by-products are landfilled and not recycled. These by-products contain metal oxides and minerals including iron oxide, zinc oxide, magnesia or alumina. Apart from the wasted valuable materials, the restriction of landfill space and stricter environmental laws are additional motivations to avoid landfill. The aim of the Fines2EAF project, funded by the European Research Fund for Coal and Steel, is to develop a low-cost and flexible solution for the recycling of fines, dusts, slags and scales from electric steel production. During this project, an easy, on-site solution for the agglomeration of fine by-products from steel production has to be developed from lab scale to pilot production for industrial tests in steel plants. The solution is based on the stamp press as the central element of the agglomeration process. The stamp press provides the benefit of being easily adapted to different raw materials and different pressing parameters, such as pressing-force and -speed, or mold geometry. Further benefits are that the stamp press process requires less binding material than the pelletizing process, and that no drying process is required as is the case with the pelletizing process. Before advancing the agglomeration of by-products via stamp press to an industrial scale, different material recipes are produced in lab-scale experiments and the finished agglomerates are tested for their use as secondary raw materials in the EAF. Therefore, the tests focus on the chemical and thermal behavior of the agglomerates. Chemical behavior, volatilization and reduction behavior of the agglomerates were investigated by differential thermogravimetric analysis combined with mass spectroscopy (TGA-MS). In addition, two melts with different agglomerates are carried out in a technical-scale electric arc furnace to increase the sample size.

Adaptable SVC Design Methodology for Power Quality Improvements in Steel Melting Shops

In 2019, India was the second-largest steel producer with total crude steel production of 112.3 metric ton [12]. There were lots of development actions taken in the starting of 90’s to promote more investments on producing steel and making it a bigger industry supporting country’s economy. Even though large amount of produced steel is utilized within the country for infrastructure, automobile and other consumable industries, still India is the seventh-largest exporter of steel. Also, Steel industries are not new to India. The oldest was TISCO and it started its production in 1907. Being said that, we have come long way in technology and science that all the steel plants need to be modernized and adapted to become more efficient, economical and productive. This paper presents one of such technology that being developed in the modern engineering word to make it adaptable in the steel industries where – Efficiency, energy consumption, quality and production can be improved significantly.

Analysis of the influence of technological parameters of steel smelting in top blowing oxygen converters on metal oxidation

The article considers the influence of technological steelmaking parameters in an oxygen converter on the oxygen content in steel before tapping. Today, CELOX is an effective, but at the same time expensive method for measuring the oxygen content in steel. The information obtained using this device allows you to accurately determine the ferroalloys consumption for deoxidation of steel. Since the oxygen content in steel before production directly affects the ferroalloys and aluminum consumption, necessary for steel deoxidation, the aim of this work was to create a mathematical model that allows determining the oxygen content in steel before tapping, taking into account the controlled melting parameters. The object of the study was a top blowing oxygen converter of 60 t capacity. The following analysis was carried out for 3PS steel grade. To create a mathematical model, the factors that have the greatest influence on the oxygen content in steel before tapping were previously selected by the method of correlation analysis. Such factors included the carbon, manganese, sulfur and phosphorus content in steel before tapping, its temperature and specific consumption of oxygen. Using the method of multiple regression analysis, a mathematical model was determined, which allows determining the oxygen content in steel before tapping at the end of each melt. Comparison of the actual data on the oxygen content in steel before tapping with the results of calculation using the model showed their high convergence, which confirms the adequacy of the obtained model. The application of the developed mathematical model for predicting the oxygen content in steel before tapping in a real metallurgical enterprise will allow reduce consumption of ferroalloys and alumina for deoxidation of crude steel.