I.V. Chumanov

Liquid-Phase Reduction of Steelmaking Wastes

Results are presented from a study of the liquid-phase reduction of the pre-concentrated metallic component of discarded steelmaking slag. The cost-effectiveness of this technology is evaluated and it is shown that it is best used as the second stage of a two-stage slag recycling operation.

Study and analysis of the structural constituents of billets hardened by fine-grained particles and formed by centrifugal casting

The structural and phase constituents of metal samples cut from hollow tube billets hardened by fine tungsten and silicon carbides and formed by centrifugal casting are studied.

Solid-phase reduction of waste products from steelmaking

The feasibility of the solid-phase reduction of steelmaking slags at 600–1300°C is analyzed and substantiated experimentally. The results that are obtained show that it is best if solid-phase reduction is used as one stage in the beneficiation of slag and is followed by liquid-phase reduction.

Interaction between tungsten monocarbide and an iron-based metallic melt

A technique and results of investigation of compacted tungsten carbide substrates by scanning microscopy are reported. Samples are prepared in the course of studies of the wettability of tungsten carbide substrates with the iron melt, which are performed in accordance with the sessile drop method using two different heating strategies, namely, contact and noncontact heating of metal.

Improving the processing of steelmaking waste. Part 1. Thermodynamic analysis

New approaches are required in the industrial processing of tailings slag from steelmaking. It has been shown in recent years that slag may be processed to obtain not only construction materials but also metal suitable for industrial use. In the present work, we study the expediency of reducing steelmaking slags as to obtain metallic and oxide phases for use in steelmaking and the construction industry. In particular, we consider slag from the tailings at Zlatoust Metallurgical Plant. FactSage software (version 6.4) is used for thermodynamic modeling of high-temperature slag reduction. Three slag compositions are considered, with 5, 10, and 15 wt % FeO. Modeling is undertaken for temperatures at intervals of 5°C in the range 750–1650°C, at a gas pressure of 0.1 MPa. We assume that a known excess of carbon (graphite) is introduced in the system. For convenience of analysis, the basic calculation results are presented as temperature dependences of the masses of the components and the composition of the phases considered. Modeling shows that, beyond 1340°C, practically all the iron is reduced and passes to the melt. Nickel and copper behave analogously. However, the results indicate that complete extraction of manganese in the metallic melt on reduction by carbon should not be expected. Even with maximum manganese extraction in the metallic melt, its presence in the slag and gas phases remains pronounced. The volume of gas phases formed in reduction at different temperatures is estimated. Modeling convincingly shows that, over the whole temperature range considered, carbon monoxide predominates in the gas phase. Information regarding the enthalpy of the system as a function of the temperature permits estimation of the thermal energy that must be expended to bring the system to a state at which the required reduction processes are possible.

Experiments on Obtaining Nanostructured Metallic Materials and their Investigation

This paper describes experiments on the introduction of fine particles in the melt is crystallized in the preparation of centrifugally cast billets. To predict the distribution of particles in the crystallizing melt was conducted mathematical modeling of the process. To confirm the data obtained by mathematical modeling experiments were conducted to obtain a centrifugal-cast billets with the introduction of fine particles. The investigation of the microstructure of the samples obtained. Comparing the data obtained about the conduct of computer simulation and real experiment, the distribution of particles in the melt crystallizing. In conclusion, this article presents the findings of the work done.

Improving the processing of steelmaking waste. Part 2. Development of the basic processing system

The expediency of reducing steelmaking slags to obtain metallic and oxide phases for use in metallurgy and construction is studied experimentally. Slag from the tailings at Zlatoust Metallurgical Plant is investigated. Experiments are conducted on the reduction of slag samples by carbon. The composition of the experimental samples is determined by X-ray spectral microanalysis. Experimental and theoretical data indicate that 20% (or even more) of the initial slag mass may be converted to metal by reduction. Practically complete reduction of the iron in the slag is possible. Significant proportions of the chromium, nickel, manganese, and other valuable components may pass to the metallic phase. Reduction of the liquid slag is expedient at 1500°C or more, so as to extract the metals more completely and form a consolidated metal phase. Preliminary solid-phase reduction of the slag at 1100–1200°C is found to be expedient. This process converts much of the iron present as oxides in the slag to a form susceptible to magnetic separation. Subsequent magnetic separation allows the fraction with an elevated content of valuable metals to be extracted from the oxide phase, which has a low metal content. The oxide fraction may be used in construction materials. In the design of systems based on these principles, utilization of the large quantities of carbon monoxide and metal vapor in the gas phase is recommended. One possibility is to use the carbon monoxide for preliminary solid-phase reduction of the slag. This research permits the development of an efficient system for processing slag tailings.

Increasing Corrosion Properties of Steel 04Cr25Ni6NMo3

The paper presents a method for increasing stainless steel 04Cr25Ni6NMo3 corrosion-resistant properties. An increased corrosion resistance develops due to the stabilization of the structure of titanium steel. The titanium additive changes the phase composition of the carbide phase and enhances the corrosion-resistant properties. Change of the phase composition of the carbide phase is analysed by means of the thermodynamic modelling.

Yttrium Oxide Wetting Angle Examination

The current paper presents yttrium oxide wetting angle examination. The test was performed in accordance with two different methods: contact and noncontact heating. Upon completion of the test, microstructural and spectral analysis of substrate/metal contact areas was conducted. Test findings are listed in the Conclusions.

The Study of the Contact Angle of Silicon Carbide High-Carbon Iron Melt

The current paper concerns the angle of silicon carbide wetting with high-carbon molten iron under vacuum. Our research was conducted with a wetting examination complex at the Institute of Energy and Interfacial Interactions (Genoa, Italy). It has been revealed that reaction of the substrate with a high-carbon molten metal results in the gaseous phase formation. We have also ascertained the temperature rate at which the substrate/metal reaction with gas formation starts.