Resource utilization strategy of Kanbara Reactor (KR) slag: Oxidation desulfurization, material cycle, low-carbon green pathway

Abstract

The low-carbon greening of metallurgical solid waste treatment is an inevitable choice for the sustainable development of the iron and steel industry. China's desulfurization slag stock is substantial, yet there is a dearth of suitable treatment methods and secondary use technologies for desulfurization slag. The issue of desulfurization residue resource application demands prompt resolution. In this study, X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) were employed to analyse the composition and structure of the physical phase in the slag. Additionally, thermal oxidative desulphurization was utilized to remove sulfur from the slag in the form of SO₂ and to reuse the treated slag in the desulphurization process of molten iron. The results demonstrated that the sulfur present in the desulfurization slag existed in the form of CaS in the surface layer of the slag particles. The highest desulfurization rate of slag was achieved when Fe₂O₃ was employed as the oxidant, reaching 98.43 %. The desulfurization rate of molten iron in the initial recycling of treated slag was 93.22 %, with the [%S] of the molten iron being 0.0035 %. When the treatment slag is reused, it can be recycled twice under actual production conditions. In anticipation of a novel approach to the efficient and comprehensive utilization of KR slag. The treatment slag after oxidation desulfurization is directly reused for molten iron pretreatment, the residual heat in the slag be fully utilized. It not only increases the utilization value of KR slag resources, but also reduces the consumption of slag-making materials. The process pathway has the potential to transform bulk industrial solid waste into valuable resources, thereby facilitating an environmentally friendly and low-consumption recycling of KR slag.