COMPUTER SYSTEM OF CONTROL OF SLAG MODE IN MODERN blast furnace conditions

The functional capabilities, methodological foundations and information software of a modernized computer system for controlling the slag regime of blast furnace smelting, developed at the Institute of Ferrous Metallurgy on the basis of fundamental principles in the physicochemical and mathematical modeling of metallurgical melts and systems based on the concept of directional chemical bonding, are considered. The system provides a predictive calculation of the complex of technological properties of the final blast furnace slag: viscosity, melting points, enthalpy, and desorption capacity. Operational assessment of the slag regime using the Slag system as part of the process control system allows efficiently and up-to-date solving the problems of optimizing the slag regime and pig iron quality under unstable blast furnace conditions

Recycling of the Steelmaking by-products into the Oxygen Converter Charge

In the technological process of the steelmaking plant, secondary products are produced in parallel with the production of the main product, which have the character of secondary by products or industrial waste. The major secondary products of steelmaking production include waste gases, process fluids, flue dust, sludge, slags and mill scales. The paper presents the results of research project directed to the utilization of demetallized steelmaking slag and oxygen converter flue dust in charge of top blowed oxygen converter. The influence of demetallized slag additions on slag regime in converter and chemical composition of final slag is described and discussed. Recommendations concerning amount of demetallized slag additions are also presented. Flue dust was recycled in form of briquettes. No significant effect of the recycling demetallized converter slag and flue dust briquette on process of hot metal refining and on quality of produced steel were recorded. Regarding the achieved results it can be confirmed that the use of the secondary products like demetallized slag and convertor flue dust in form briquettes, is environmentally acceptable as well as the use of natural materials and poses no increased risk to human health or the environment.

Technology elaboration for borate ore utilization at iron ore pellets production

Input of intensifying additives, influencing the strengthening of iron ore pellets, can be one of methods to strengthen the pellets and to decrease the volume of fines in them. Boron oxide ore borate ore can be used as such additives. Study of technology aspects of boron-containing pellets production and elaboration of technology of boron input into Kachkanar vanadiumcontaining raw materials was the purpose of the study, aimed at exclusion from BF burden of sinter, which does not contain vanadium. A possibility was justified to use borate ore at iron ore pellets production by a partial substitution of bentonite. Influence of borate ore additives on pellets metallurgical properties studied. As a result of laboratory studies it was determined, that the borate ore has not binding properties and its utilization is possible only in a mixture with bentonite. Optimal content of borate ore in pellets determined, exceeding of which a decrease of reducibility is observed, accompanied by a considerable swelling, which makes impossible the utilization of such pellets in blast furnaces. It was shown, that input of optimal volume of borate ore additives enables to keep the reducibility and swelling at the level of Kachkanar pellets being produced. The mechanism of borate ore content influence on strength characteristics of burnt pellets and their behavior during reducing studied. The regularity of borate ore additives influence on cold and hot pellets strength determined. It was determined, that at input of 0.5% of borate ore practically does not influence on the pellets reducibility while swelling will be constant. The input of borate ore up to 2% will result in a sharp increase of swelling. The decrease of reducibility with simultaneous increase of swelling of pellets having more than 0.5% of borate ore does not allow using such pellets in blast furnaces. Recommendations provided for slag regime optimizing, decreasing of metal losses with slag and test BF heats of pellets, having optimal additives of borate ore and bentonite carrying out.

Evaluation of Influence of Briquetted Synthetic Slags on Slag Regime and Process of Steel Desulphurization

This paper presents the industrial results of evaluation of efficiency of synthetic slags during the treatment of steel at the equipment of the secondary metallurgy under conditions of the steel plant VÍTKOVICE HEAVY MACHINERY a.s. The aim of the heats was to assess the influence of the briquetted and sintered synthetic slags based on Al2O3 aiming the course of the steel desulphurization and slag regime during the production and treatment of steel grade 42CrMo4 with the technology EAF→LF→ VD. Within the plant experiments, basic parameters influencing the steel desulphurization and slag regime were monitored: desulphurization degree, basicity, content of easily reducible oxides, proportion of CaO/Al2O3 and Mannesmann’s index. Obtained results allowed to compare the steel desulphurization and to evaluate the slag regime. It was proved that the synthetic slag presenting the briquetted mixture of secondary corundum raw materials can adequately replace the synthetic slag created from the sintered mixture of natural raw materials.