The reduction kinetics of serial phase transitions of iron oxides during reduction to a metallized state with different modes of technical hydrogen supply has been studied and substantiated. The results of the pellets formation when 3-5 % molasses is added to the red mud as a binding reagent are presented. The dependences of the reduction rate of iron oxides on the hydrogen flow rate are obtained. Based on the results of the experiments, a kinetic model was constructed, and with the help of X-ray phase and spectral analysis, it was proved that the agglomerates formed after heat treatment received high strength due to the adhesion of reduced iron particles with red mud particles. The use of a new type of charge materials in melting units will reduce the amount of emissions and dust fractions, as well as increase the metal yield.

Использование спеченного сорбента для удаления сероводорода из отходящего промышленного газа при грануляции металлургических шлаков

Red mud (RM), the by-product generated during the alumina extraction process, is considered a valuable secondary raw material, since iron (20-54%) represents its major constituent. Accordingly, the suitability of recycling this RM in the sintering process of Egyptian iron ore was studied. The...

The global demand for environmentally acceptable iron ore pelletization binders has increased the interest in natural alternatives, such as Egyptian bentonite. Despite its abundance and primary composition of montmorillonite, raw Egyptian bentonite has limited swelling capacity and poor industrial performance owing to excessive impurities and heterogeneous mineralogy. This chapter examines hydrocyclone separation as a sustainable and effective method for purifying Egyptian bentonite for pelletization. This chapter covers sodium and calcium bentonite clay varieties. After purification, bentonite clay is the most popular binder for iron ore pelletization because of its binding and mechanical qualities. This shaper examines the geological distribution and mineralogical features of Egypt’s necessary bentonite deposits, focusing on montmorillonite-rich areas such as Ayun Musa and El-Barqan. Furthermore, this chapter covers advanced characterization methods (X-ray diffraction (XRD), X-ray Fluorescence (XRF), zeta potential) and complementary modifications. Bentonite is purified using physical processes, which involve mechanical separation, and chemical procedures, which utilize targeted reactions to change the clay’s composition or surface chemistry. Chemical purification may damage the crystalline structure of montmorillonite; therefore, physical purification is safer and more effective for Egyptian bentonite. Hydrocyclone-based physical purification improves the purity of bentonite while conserving its mineralogical structure. Hydrocyclone-purified bentonite enhanced green and dried iron pellets. Purified bentonite improved the pellet hardening via thermal consolidation. The absence of toxic phases and sodium-rich smectite facilitated solid-state diffusion and liquid-phase formation. These variables created a strong sintering bridge. This chapter emphasizes the strategic necessity of valorizing local bentonite resources for sustainability and circular economy principles in the iron and steel industry.

This study demonstrates a circular economy approach by synthesizing a composite adsorbent from slag, slag‐derived magnetic iron nanoparticles, chitosan, and activated carbon (Cs/Sg/MGNPs/AC) for efficient methylene blue (MB) dye removal from aqueous solutions, followed by valorization of the spent adsorbent as an electrocatalyst for urea oxidation reaction (UOR). The composite was fully characterized using FESEM‐EDX, XRD, FTIR, BET nitrogen adsorption, and DLS techniques. It exhibited superior adsorption performance with near‐complete removal (> 98%) at optimal conditions. Adsorption mechanisms were elucidated through isotherm analysis (Freundlich model), kinetic modeling (pseudo‐second‐order and Elovich models), and intraparticle diffusion studies. The process was influenced by pH, adsorbent dosage, contact time, initial dye concentration, and ionic strength. The composite demonstrated selectivity toward cationic dyes over anionic dyes due to electrostatic interactions and functional group characteristics. Following adsorption, the MB‐loaded composite (Cs/Sg/MGNPs/AC/MB) was successfully repurposed as a UOR electrocatalyst, achieving a remarkable current density of 179.90 mA/cm ² in 1.0 M urea solution, representing a 14.2% enhancement over the pristine composite (157.47 mA/cm ² ). The MB‐loaded catalyst also exhibits superior electrochemical performance with enhanced double‐layer capacitance (0.5815 mF/cm ² vs. 0.3265 mF/cm ² ), lower charge transfer resistance (1.09 Ω vs. 1.47 Ω), and excellent long‐term stability (85.60 mA/cm ² vs. 69.15 mA/cm ² over 3600 s). This work establishes a sustainable pathway for converting industrial waste and spent adsorbents into value‐added materials for environmental remediation and energy applications.