To strengthen the granulation behaviour of concentrates and thereby improve the permeability of the sinter bed. In this paper, granulation experiments were conducted for the case of concentrates as adhesive powders, and five kinds of coarse ores were used as nuclei particles. Then, the effect of characteristics of coarse ores on the granulation behaviour of concentrates was investigated. Furthermore, optimised blending ore was explored to strengthen the granulation behaviour of concentrates by sinter pot tests. The results showed that the growth index had a positive correlation with the circularity degree but a negative correlation with the contact angle and water absorption of coarse ores. In addition, the granulation index increased by 30 % by optimising the blending ore when the sinter blending ore contained 15 mass% concentrate. The vertical sintering speed increased from 26.32 to 29.82 mm·min⁻¹, the yield and productivity increased by two points percent and 14.87 %, respectively.

Steel slag (SS), as a major solid waste of the steel industry, has CO₂ sequestration potential due to its rich calcium and magnesium alkaline components. SS carbonation is a promising strategy gaining industrial traction to simultaneously treat industrial solid waste and greenhouse gases. This article firstly describes the properties of SS and summarizes the research progress of SS carbonation. The classification of mineral carbonation technology is introduced, and the advantages and disadvantages are analyzed. The key factors affecting the SS carbonation are discussed. Then, the current industrial application status and life cycle assessment results are summarized. Finally, the conclusions are summarized, and the future research direction is proposed. Carbonation of SS can effectively fix CO₂ and produce high-value-added products, realizing a win–win situation of environmental and economic benefits, which is of great significance to the green transformation of the steel industry and the realization of the “double carbon” goal.

Cold-rolling oily sludge contains high amounts of oil and iron resources that can be recycled by pyrolysis. We investigated the pyrolysis behavior and volatile products of oily sludge by thermogravimetric analysis (TG) coupled with Fourier transform infrared spectroscopy (FTIR) and a pyrolyzer (PY) coupled with gas chromatography/mass spectrometry (GC/MS). The pyrolysis process was divided into three stages: H₂O drying and CO₂ desorption at low temperatures (below 393 K); the volatilization of low-molecular-weight organics and the covalent bond cleavage of C=C, C-O, and C-H in the medium-molecular-weight organics at medium temperatures (393–844 K); and chain scission of the high-molecular-weight organics and reduction of iron oxides by CO at high temperatures (above 844 K). The weight losses of oily sludge in the three stages were 0.4 wt %, 47.9 wt %, and 14.7 wt %, respectively. According to the kinetic models, stage 2 and stage 3 could be described with the second-order and third-order reaction models, and their activation energies were 40.22 kJ/mol and 214.99 kJ/mol, respectively. The compounds in the volatile products were identified by FTIR and GC/MS. The organics in the volatile products from stage 2 pyrolysis mainly consisted of aliphatic hydrocarbons, fatty acids, esters, ketones, and nitrogen compounds, while the volatile products from stage 3 predominantly contained aliphatic hydrocarbons, mononuclear aromatic hydrocarbons, and small amounts of nitrogen compounds and CO, suggesting the occurrence of chain scission of heavy organics.

Concentrates have advantages of high ferrous grade, less harmful impurities and lower price. However, the small size and poor granulation behavior of concentrates could deteriorate the permeability of the sinter bed and reduce sinter productivity, thus making it difficult to use concentrates effectively. Therefore, in order to strengthen the granulation behavior of concentrates, granulation experiments were carried out and experiment samples made with one kind of concentrates and five kinds of fine iron ores were produced in this paper. Then, the effects of water absorbility and wettability of fine iron ores on granulation behavior of concentrates were investigated. Furthermore, optimized ore blending recipes were proposed to strengthen the granulation behavior of concentrates by sinter pot tests. Results show that the granulation behavior of concentrates was improved for the samples exhibiting high maximum capillary water and small contact angle in fine iron ores. Compared with the scheme of blending ores containing 15 mass% concentrate, the growth index of quasi-particles increased by 20.62% in the case of iron ore BR-2 replacing half of iron ore BR-1, the vertical sintering speed went up from 26.32 to 29.26 mm min⁻¹, the productivity increased from 1.95 to 2.20 t m⁻² h⁻¹. The growth index of the quasi-particles increased by 30% when using iron ore AR-2 to replace half of iron ore AR-1. The vertical sintering speed and the productivity of sinter improved to 29.82 mm min⁻¹ and 2.24 t m⁻² h⁻¹, respectively. The results help to improve the granulation behavior of concentrates by optimizing the blending ore recipes, based on the characteristics of fine iron ores, and thus use these concentrates more efficiently in the sintering process.