The MgO content in ladle slags is addressed. It is important to tend to, but not to exceed the MgO saturation limit during slag induction. Exceeding this limit will have an adverse effect on the refining properties of slag. The heating temperature of the slag and metal in a ladle furnace is studied. It is shown that the MgO saturation limit varies during steel processing. Taking this variation into account allows adjusting the target content of this oxide when calculating the amount of injected MgO-containing materials, ensuring low corrosivity of homogeneous slag to the lining, while maintaining its refining properties.

EVRAZ NTMK JSC has significant amount of blast furnace sludges, that accumulated in dumps. Chemical and phase analysis of that sludges was carried out. It has shown significant amount of zinc sulphate, which prevents such sludge utilization in a blast furnace. Moreover, zinc sulphate requires a high temperature unit for recycling by common schemes. The possibility of zinc sulphate conversation into oxidized zinc with simultaneous metallized residue obtaining under the common for Waelz process temperatures was confirmed in laboratory. The obtained during laboratory experiments metallized residue is suitable for using in blast furnace as charge addition. The results of a thermodynamic analysis of the zinc sulphate conversion to oxide and the physicochemical basis for the extraction of such zinc forms are presented. Theoretical calculations and laboratory experiments confirmed that sludges with zinc sulphate could be suitable materials for blast furnace. But, sludges of different processes allow to obtain fired briquettes with different physical properties.

The influence of a REM-containing Insteel 7 complex modifier on the structure and the contents of dissolved gases and sulfur in Fe–Al alloys with an increased aluminum content (11–15 wt %) melted in an open induction furnace is studied.

The work presents the study and development of the joint processing of ladle furnace and electric arc furnace slag with no waste left. The experimental results proved that slag could be utilized jointly. The study revealed the chemical compositions of slag, which allow the effective utilization. The products of this utilization are cast iron and Portland clinker without any residue left. Final products meet the requirements of normative documents. The study also presents the operations for joint processing.

The mathematical processing results of a number of EAF-135 melts electrical parameters are presented. The influence of the foamy slag formation, molten metal carburization and the harmful impurities oxidation on the change in electrical parameters is analyzed. The methodology for determining the metal oxidation from the electrical melt parameters is characterized. In the presented form, the technique is cumbersome for the rapid assessment of the oxidation process intensity and requires refinement. Keywords: Metal oxidation, electric parameters, electric arc furnace

Synthesis of the portland cement clinker in the presence of a significant amount of SO3 is difficult, due to the tri-calcium silicate formation suppression. Since some technogenic formations contain a significant amount of SO3, it is hard to obtain the portland cement clinker from it. The analysis of the SO3 influence on the clinker-formation thermodynamic process allowed to reveal a number of regularities of their occurrence and to propose a method for the raw mix composition calculating and its preparation, to ensure a stable portland cement clinker synthesis.

The comprehensive methodology for the zinc extraction from sulfide compounds into the oxide form with possible further reduction to metal is presented in this study. It was demonstrated in laboratory conditions during sludge treatment with Zn and ZnO obtaining. The remaining silicate products. It is proposed to recycle this material into Portland cement clinker to ensure a waste-free process. Keywords: zinc sulfide, zinc oxide, sludge recycling, Portland cement clinker, waste-free recycling

Analyse of the blast furnace charge chemical content changing with the JSC EVRAZ NTMK raw materials base alteration was carried out. That expected change would result in TiO2 content increasing in the blast furnace slags. That increasing would lead to carbonitride formation in the upper levels of the blast furnace, which reduce technical parameters of the blast furnace operation by reducing effective volume of the furnace and derange regular charge moving. Possible ways of that problem solving was shown. It was proposed the complex technology, that affect 3 technological stages: agglomeration, blast furnace process and out-of-furnace treatment of steel. Converting of TiO2 into CaO·TiO2 allows to delay carbonitride formation due to increasing required temperature for that process. In that case, carbonitride formation would move to the tuyere zone of blast furnace, where it increase lining durability. The proposed technology was industrially tested, and the main idea was proved. Few problems were found during industrial tests, but theoretical solving of them was proposed.

The processes of iron oxides’ reduction have a complex physicochemical mechanism, with the participation of solid, liquid, and gaseous substances. The article discusses the existing models for the reduction of iron oxides and provides data on the thermodynamic possibility of carrying out the reactions of their reduction through the solid and gas phases. Experimental data on the reduction of iron from industrial scale, obtained by the DSC (differential scanning calorimetry) method, show the kinetic dependence of the rate and completeness of recovery on external factors: pressing pressure during sample preparation and the reagents’ composition. The pressing pressure, under conditions of iron ions’ solid-phase diffusion, has the significant effect by increasing the reagents’ contact area. Under conditions of iron ions’ comprehensive diffusion, the pressing pressure does not affect the reduction processes rate. The introduction of 10 mass.% flux into the raw mixture composition leads to a partially liquid-phase diffusion of iron ions and weakens the effect of the pressing pressure in this process. An ion diffusion-catalytic mechanism is proposed to describe the observed effects during the reduction of iron oxide of technogenic origin.

An algorithm is developed to estimate the rate of charge melting in the electric arc furnace laboratory and its geometric sizes. An electric-arc instability index is proposed as a parameter for on-line control of the heat state of the bath and the rate of metal scrap melting. In practice, a decision about turning off a furnace in melting a charge or about the beginning of the end oxidation stage of a heat is delayed, which leads to an increase in the time of furnace operation under an electric current and in the specific electric power consumption.

The article deals with issues of integrated waste-free processing of electric arc furnaces dust. It is shown that it is possible to obtain a whole range of valuable commodity products on both metal and non-metal bases as a result of the electric arc furnaces dust complex processing. Integrated waste–free processing reduces the arc furnaces dust impact on the environment and produces a number of valuable commercial products.

It is proposed to consider the oxidation potential of the ladle slag coating as the factor affecting the modification efficiency. Conditions of modifiers effective influence on steel are determined. Samples of industrial steels smelted with the determined conditions accordance are obtained. The impact of new rapidly quenched modifiers with rare-earth metals on the molten medium carbon steels 40Kh and 38KhM was studied by method of viscometry. Such steels have no hysteresis of viscosity. According to the alloys influence on the liquid steel supercooling during solidification, limits of the rational using of new alloys are established.

The microstructure, impact toughness and melting parameters of cold-resistant steel 20GL are studied. The impact toughness of the steel at negative temperature (KCV-60) is shown to be affected the most by the size of the primary (natural) grains of the metal. The size of the natural grains is shown to be dependent on the content of oxygen and (to a less degree) of silicon. Introduction of an elevated amount of slag-forming materials and aluminum into liquid metal provides the required (at most 0.005–0.008 wt.%) content of oxygen and an impact toughness (KCV-60) no less than 0.167 MJ/m2. Influence of the nonmetallic inclusions, of the size of actual grains, and of the content of pearlitic phase on KCV-60 in normalized steel has not been detected or was not obvious.

One of the main causes of the nonuniform melting of a charge in the EAF bath is found to be the asymmetry of the short circuit and interphase power transfer. The electric power deficiency at the “dead” phase of a furnace is shown to be 1.2 MWh. We propose to equalize the energy disbalance using flexible control of the operating conditions of gas–oxygen burners. For this purpose, an algorithm is developed to estimate the changes in the geometric zone sizes in the EAF bath using the technique of determining angular arc radiation coefficients. The intensity of charge melting due to arc radiation is shown to decrease sharply with increasing well diameter, and the main component of the furnace capacity is the melting of a solid charge in a molten metal bath.

Methods of ladle furnace slag stabilization are analyzed. It is shown that increasing the Al2O3 content of slag to higher than 18% results in chemical stabilization of slag. It is revealed that if the Al2O3 content is less than 30 wt.%, the refining properties of the slag do not degrade. When that content is exceeded, Al2O3 behaves similarly to SiO2, i.e., reduces the desulfurization ability of slag and makes it more corrosion aggressive. The most favorable content of Al2O3 in slag is from 12 to 25%, the properties of slag varying from basic to acidic. If the Al2O3 content is higher than 14%, the probability of formation of MgO–Al2O3 refractory spinel on the surface of refractory products increases, thereby increasing the durability of ladles and vacuum chambers.

There are two main kinds of slag in modern steelmaking industry: the electric arc furnace slag ( EAF slag) and ladle furnace slag (LF slag). The all known slag processing schemes provide the iron-containing component reduction while silicate component stays unprocessed. On the contrary, the silicate processing schemes doesn't provide the utilization of the iron-containing component. The present-day situation doesn't solve the problem of total slag utilization. The aim of this work is to investigate the opportunity of silicate product obtaining with simultaneous pig iron reduction from EAF and LF slags. The tests are conducted by the method of simplex-lattice design. The test samples are heated and melted under reductive conditions, slowly cooled and then analyzed by XRD methods. The experiment results prove the opportunity: the Portland clinker and pig iron can be simultaneously produced on the basis of these slags with a limestone addition.