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The desulfurization and dephosphorization performances have been considered to be the most challenging operations for refining ultra-clean steel. The distribution ratios of sulfur and phosphorus in the form of $$ L_{i} = {{\left( {\% \, i} \right)} \mathord{\left/ {\vphantom {{\left( {\% \, i} \right)} {\left[ {\% \, i} \right]}}} \right. \kern-0pt} {\left[ {\% \, i} \right]}} $$ as well as slag capacity concepts of sulfide and phosphate capacities in the form of $$ C_{{i^{m - } }} \propto (\% \, i^{m - } ) $$ have been extensively studied and widely applied for the description of desulfurization and dephosphorization abilities and potentials, respectively. However, the intrinsic limitations of two slag capacity concepts as sulfide and phosphate capacities regardless of slag oxygen potential $$ p_{{{\text{O}}_{2} }} $$ have seriously limited their direct applications into guiding the practical refining operations compared with the partitions or distribution ratios $$ L_{i} $$ . The theoretical limitations of sulfide and phosphate capacities have been extensively reviewed and critically assessed by comparison with the distribution ratios $$ L_{i} $$ in this contribution by taking two preferred thermodynamic conditions of both basic oxides concentration or slag basicity and slag oxygen potential as criteria. Meanwhile, the merits of two slag capacity concepts as measures for describing slag basicity like optical basicity have also been reviewed to be disruptive because the ratios of activity of free oxygen ion $$ a_{{{\text{O}}^{2 - } }} $$ in slags to activity coefficients $$ f_{{{\text{H}},i}} $$ of sulfide and monomer phosphate $$ {\text{PO}}_{4}^{3 - } $$ in slags as implicit parameters in the defined two slag capacity concepts cannot hold constants in most complex slags. Furthermore, the limitations of phosphate capacity in two ways have been restated. Moreover, the oxygen potential $$ p_{{{\text{O}_{2}} }} $$ shows a great effect on plots of the desulfurization and dephosphorization abilities against two slag capacity concepts of slags at a given temperature. The abnormally higher oxygen potential $$ p_{{{\text{O}_{2}} }} $$ can result in a suppression of the desulfurization ability of slags with a greater desulfurization potential, while the unreasonably smaller oxygen potential $$ p_{{{\text{O}_{2}} }} $$ can lead to a diminishing of the dephosphorization ability of slags with a larger dephosphorization potential. It has been verified by five case-studies covering desulfurization and dephosphorization operations that the partitions or distribution ratios $$ L_{i} $$ related to equilibrium quotients $$ k_{i} $$ of desulfurization and dephosphorization reactions of Fe-based melts by slags can be in good accordance with two preferred thermodynamic conditions. The reasonable application of two slag capacity concepts is recommended to estimate or determine the distribution ratios between slags and Fe-based melts with the aid of activity $$ a_{{\% ,{\text{O}}}} $$ of oxygen and activity coefficient $$ f_{\% ,i} $$ of sulfur and phosphorus in Fe-base melts.

The effect of argon and oxygen ion implantation both in separate and joint was carried out. Physical and chemical structure of the surface and corrosion-electrochemical behavior of 14Cr17Ni2 chromium-nickel steel was studied. Methods of potentiometry, atomic force microscopy, X-ray photoelectron spectroscopy, and microhardness measurement were used. It was found that the initial chromium-nickel steel exhibits high corrosion resistance in the medium of a borate buffer solution with the addition of a local corrosion initiator — potassium sulfate. However, steel was found to be susceptible to local (pitting) corrosion in this environment. It is shown that the implantation of argon and oxygen ions changes the nature of the corrosion-electrochemical behavior of chromium-nickel steel. Treatment with Ar+ ions enriched the sample surface with Cr atoms and reduces the overall corrosion losses of steel, but is characterized by the maximum value of local corrosion. Treatment with O+ ions provide optimal results in terms of reducing local and general corrosion. It was found that in this case, the sample surface is intensively oxidized to a depth of more than 20 nm, resulting in the formation of mixed oxides that are resistant to corrosion. There is a process similar to electropolishing of the sample surface due to partial dissolution of steel. Defects in the structure of the sample surface, on which pitting corrosion began, are “healed”. Joint treatment with Ar+ ions and O+ ions does not give noticeable advantages compared to separate implantation with these ions. Corrosion losses for samples treated only with O+ ions and Ar+ ions together with O+ ions did not exceed those for the original sample, although there are practically no passivation regions on the potentiodynamic curves. Microhardness of the samples after ion implantation coincides with the microhardness of the original sample. Result of ion implantation is no significant for change in the structural and phase structure of the surface layers of chromium-nickel steel. Ion implantation will not negatively affect the physical and mechanical properties of studied steel. The research shows that it is advisable to choose the type of implantable ions and the optimal process parameters depending on the steel grade and its application. For these purposes, the research methodology proposed in this article will be useful.

Efficient activation of CO2 at low temperature was achieved by reverse water–gas shift via chemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu–In structured oxide, even at lower temperatures. Results show that a novel Cu–In2O3 structured oxide can show a remarkably higher CO2 splitting rate than ever reported. Various analyses revealed that RWGS-CL on Cu–In2O3 is derived from redox between Cu–In2O3 and Cu–In alloy. Key factors for high CO2 splitting rate were fast migration of oxide ions in the alloy and the preferential oxidation of the interface of alloy–In2O3 in the bulk of the particles. The findings reported herein can open up new avenues to achieve effective CO2 conversion at lower temperatures., Efficient activation of CO2 at low temperature was achieved by reverse water–gas shift via chemical looping (RWGS-CL) by virtue of fast oxygen ion migration in a Cu–In structured oxide, even at lower temperatures.