Volodymyr Shatokha

Innovative approach to recovery of iron from steelmaking slags

Abstract The present work is aimed at the development of a new sustainable method for the utilisation of valuable elements from the steelmaking slag. In the framework of the innovative concept earlier proposed by the authors for utilisation of steelmaking slags, oxidation of iron mono-oxide in the liquid slag was studied experimentally in different atmospheres and in the temperature range 1623–1823 K using thermogravimetry technique. Synthetic (binary and ternary slag system) as well as industrial steelmaking slags were used in the experiments. Analysis of the reaction products was carried out using X-ray diffraction method. A possibility to transform the non-magnetic iron bearing compounds to magnetite in the steelmaking slag by oxidation has been confirmed.

Study on effect of coal treatment with blast furnace slag on char reactivity in air

Abstract Waste heat of the blast furnace slag might be recovered in an allothermal coal gasification process to produce an alternative fuel for ironmaking. The effect of heat treatment of brown and sub-bituminous coals mixed with blast furnace slag on the properties of the produced chars was studied. More porous chars were formed at charring in contact with the slag. The development of better porosity in sub-bituminous coal chars was observed in contrast to brown coal, where charring was followed by cracking. Thermal analysis was used to study the behaviour of chars and to derive Arrhenius kinetic parameters for oxidation in air. The behaviour of chars is affected by the simultaneous development of thermally activated oxidation and decomposition processes. Higher volatile ignition temperature for chars produced with slag was observed. The activation energy for the combustion of chars produced with slag was essentially lower, while the pre-exponential factor is higher for chars produced without slag.

Iron ore sinter porosity characterisation with application of 3D X-ray tomography

Abstract X-ray tomography has been applied for the estimation of iron ore sinter porosity. Procedures to distinguish open and closed pores and to estimate the volume and the equivalent diameter of each pore were developed, providing the possibility to calculate the amount of porosity considering open and closed pores separately. The effect of the sinter mixture composition on the porosity parameters was investigated, and a comparison with a mercury intrusion measurement is also presented. Reducibility tests were performed for the samples, the porosity of which had been previously identified by tomography. The fact that samples with a premeasured porosity could be analysed with other characterisation methods opens new possibilities to understand the effect of the porosity on the properties of the sinter.

Metal Recovery and Inorganic Eco-Materials from Tailings by Leaching-Sintering Processes

Integrated tailings utilization of metallic ore is an overall situation associated with additional resourse storage, cleaning exploitation of mine, and environmental concerns. The purpose of the present work is to study and develop several corresponding recycling routes for tailings in accordance with chemical component and paragenesis state of minerals. Four typical gangues are collected from Chinese western dominant mine, discharged after mill run from rare earth metal ore, iron ore containing titanium and vanadium, nonferrous paragenetic ore (Pb, Zn, Sn, Sb, and other nonmetallic elements), and multimetal bonanza ore, respectively. To meet the demands for national recycling economics, it is necessary to design for recycled materials involving recovery of metal and preparation of advanced ecological ceramics through several novel approaches. Experimental results indicate that Ce, Y, and Nb rare metals have been leached from those tailings, and high performance Ca–Sialon can be synthesized from the as-discarded residues. A newly metal bonded ceramic eco-material, identified as Fe3Si–TiCN–MgAl2O4 by XRD are discovered, whose fracture tougness is 12 MPa·m1/2, which is successfully prepared by Carbonothermal Reduction Nitride route using iron–titanium tailing ore based on thermodynamics calculation. Zinc oxide and lead oxide powders can be extracted from nonferrous mineral tailings by hydrometallurgy process, regarded as fresh precursory powders for Pb(Zn1/3Nb2/3)O3 functional ceramics, whereas magnetic Fe3O4 nanopowders are refined, originated from multimetal tailing ore by leaching-separating-precipitation. In addition, a practicing software, Search and Analysis System on Recycling of Solid Waste, has been developed to promulgate common knowledge to worldwide readers (Web site: http://recycling.net.cn).

A STUDY ON TRANSFORMATION OF SOME TRANSITION METAL OXIDES IN MOLTEN STEELMAKING SLAG TO MAGNETICALLY SUSCEPTIBLE COMPOUNDS

Sustainable development of steelmaking requires solving a number of environmental problems. Economically feasible and environmentally friendly recycling of slag wastes is of special concern. Research of the team representing National Metallurgical Academy of Ukraine, Royal Institute of Technology, Carnegie Mellon University and URS Corp revealed a possibility of the controlled phase transformations in the liquid silicate melts followed by formation of the magnetically susceptible compounds. This approach enables selective recovery of metal values from slag. In this paper, the results obtained and further research directions are discussed. A possibility to exploit physical properties of the transition metals, typical for the metallurgical slags (such as Fe, Mn, V and others), and corresponding specific properties of their compounds, such as non-stoichiometry, mixed valency, pseudomorphosis, thermodynamic stability etc, in production of value-added materials from slag wastes is discussed. The results of the studies of thermodynamics and kinetics of oxidation in slags followed by phase transformation with binary, ternary and complex oxides under various physicochemical conditions are discussed in the view of their application for production of the materials with predefined physical properties. Peculiarities of precipitation in slags with various basicities are analysed and demonstrate capacity of the proposed approach in the production of the material with a given structure and size – for example, nano-sized crystals with structure of spinel. The approaches towards industrial realization of the developed method are also discussed.

Effect of coal treatment with molten blast furnace slag on char properties

Abstract The effect of sub-bituminous coal treatment with molten blast furnace slag on the char properties was studied towards development of an allothermal coal gasification technology with utilising the slag heat energy. Contact with molten slag is followed by deeper conversion of sub-bituminous coal, resulting in obtaining chars with enhanced cumulative open pores volume, porosity, specific surface area and adsorption capacity, which might be explained by catalytic effect of slag on the coal pyrolysis. Taking into account the role of adsorption in the heterogeneous reactions, treatment with slag may favour chars gasification kinetics.

Application of a Peat as an Additive to Prepare Ferrous Gas-Cleaning Sludge for Sintering

The purpose of the research is to increase consumption of iron-bearing gas cleaning sludge to the sintering mix in order to utilize both fresh and stored wastes. Utilizing of iron-bearing sludge produced by gas cleaning facilities of integrated steelmaking plants is an urgent problem. In Ukraine, steelmaking industry produces over 10 million tons of such wastes a year. With Fe content of 35–55% sludge is valuable by chemical composition but its application as component of a burden to produce sinter is challenged with high moisture content and tendency to self-aggregation. Activated peat has been applied as high absorbency additive to sludge. Moisture capacity of a peat ensures absorption of water by this material from the sludge within the whole range of moisture content. Treatment of dehydrated sludge with the peat allows the obtaining of a mixture with mechanical properties comparable to those of other sintering mix components. Preparation of sludge produced by wet gas cleaning systems of blast furnaces, sintering plant, BOF (basic oxygen furnace), and open-hearth furnaces while mixing with peat during formation of piles has been experimentally investigated. Increasing of sinter yield ratio and plant productivity in the industrial conditions has been observed.

Potential of Best Available and Radically New Technologies for Cutting Carbon Dioxide Emissions in Ironmaking

Transition to a low-carbon economy requires modernisation of the iron and steel industry. Improvement of energy efficiency of blast furnace ironmaking, development of new and rapid commercialisation of currently developed innovative ironmaking technologies and deployment of carbon capture and storage/utilisation technologies are required to reach sustainability targets. Four scenarios with various combinations of energy efficiency enhancement and different market penetration of breakthrough ironmaking technologies have been developed and analysed. Deployment of the best available technologies is indispensable though not sufficient for cutting CO2 emissions to an extent required by the climate change mitigation targets established by the International Energy Agency. Increased share of secondary steel produced via EAF method using gradually decarbonised electricity also is a prerequisite for substantial cutting of CO2 emissions. Rapid and wide commercialisation of currently developed innovative ironmaking technologies after 2020 allows for reaching emission levels consistent with the targets up to 2030–2040, depending upon the market penetration. However, in the following years even in the most radical modernisation scenario, new impulse is needed to align CO2 emissions with sustainability targets. Hydrogen-based ironmaking, enhanced material efficiency, greater share of secondary steel production and CCS/CCU technologies can play the role of such impulse. Delayed and limited mitigation actions will result in much greater amounts of CO2 emitted to atmosphere with unavoidable impact on climate.

Preface to the Special Topic on AdMet 2015

The International Conference on Advances in Metallurgical Processes and Materials (AdMet 2015) was held in Kyiv, Ukraine, on June 3–5, 2015, and researchers and engineers from 12 countries attended the event. The first AdMet conference was held on 2007 in Dnipropetrovsk, Ukraine, and the second conference was initially planned for 2014. However, because of the political situation in Ukraine, it was rescheduled for 2015. Despite the intentions expressed by the organizers to relocate the conference to another country, they decided to keep it in Ukraine to reflect the substantial contributions made by Ukraine to the theory and practice of metallurgy. The local organization of AdMet 2015 was supported by the Paton Electric Welding Institute, National Metallurgical Academy of Ukraine, and Elmet-Roll Company. Multidisciplinary cross-country collaboration is becoming increasingly important with respect to sustainable development targets. Therefore, the purpose of AdMet 2015 was to bring together researchers from the domains of process metallurgy and materials science in order to share the latest advances in research and development, assist international collaborations for solving current and future societal and technological challenges, and promote the transfer of innovative technologies and materials. The conference topics covered thermodynamics, innovative metallurgical processes, advances in ironand steel-making technologies, process control, automation, online analysis, the design and properties of materials, modeling and simulation processes and materials, special melting, and environmental issues in metallurgy. From the proceedings of AdMet 2015, we have chosen several articles that discuss the environmental issues in metallurgy, especially the recycling, recovery, and reuse of by-products and waste, to meet the scope of the Journal of Sustainable Metallurgy. In addition, one review paper discussing the present situation of the steel industry in Ukraine is included. We hope this special topic is useful to many researchers by providing updates on the recent advances in this field. The third AdMet will be held in Lviv, Ukraine, in 2018, and it is our pleasure to invite the readers of the Journal of Sustainable Metallurgy to this conference.

Study on Water Splitting Potential of Some Metallurgical Wastes for Production of Hydrogen

Development of reliable and cost-effective technologies to produce hydrogen is very important in the context of climate change mitigation. Even partial substitution of carbonaceous fuels and reductants in ironmaking may reduce CO2 emissions considerably. Hydrogen-based ironmaking technologies are being developed; however, their commercialization is constrained by availability and cost of hydrogen. Approaches such as solar hydrogen, fuel cells, and bio-hydrogen are being extensively studied worldwide; however, for the most part, these developments have uncertain potential to produce hydrogen for industrial applications in ironmaking owing to their complexity, insufficient productivity, and high cost. The potential of some widely available materials and wastes to be used as contact mass in the thermo-chemical water splitting processes for on-site production of hydrogen at a steel factory towards future hydrogen-based ironmaking is studied in the current paper by using thermodynamic modeling.