Insights into the Roasting Kinetics and Mechanism of Blast Furnace Slag with Ammonium Sulfate for CO₂ Mineralization

Abstract

A route for the indirect carbonation of different minerals using (NH 4 ) 2 SO 4 (AS) as a recyclable reagent has been recently proposed. For saving energy, the extraction of alkaline components, such as calcium and magnesium, is typically expected to occur at the roasting stage. To enhance the extraction efficiency, the kinetics and mechanism of the reaction between AS and blast furnace slag (BFS), a Ca/Mg-containing mineral, were investigated in this study. The results showed that the reaction consists of two steps: the decomposition of AS into ammonium bisulfate (ABS) and the reaction between the ABS and the BFS. Isothermal kinetics and equal conversion methods were used to determine the apparent activation energy and reaction-controlling steps in different temperature ranges. The results showed that the decomposition of AS was a chemicalreaction-controlled step with an apparent activation energy of 102 kJ• mol −1 . On the other hand, the reaction between ABS and BFS, which was very quick, was controlled by the ABS supply. During the reaction, a product accumulation layer was generated around the nonreactive BFS particles. However, it was found that ABS can easily pass through this layer and react with the BFS core. The formation of ABS was the limiting step in the roasting process.

Decrypting Catalytic NOX Activation and Poison Fragmentation Routes Boosted by Mono- and Bi-Dentate Surface SO32–/SO42– Modifiers under a SO2-Containing Flue Gas Stream

“…Previous literature has pioneered catalytic AS/ABS fragmentation, yet, often interpreted their kinetic data using reverse reactions of ABS formation (ABS → NH 3 + H 2 O + SO 3 ; SO 3 → SO 2 + 1/2O 2 ), − both of which are not thermodynamically viable, as evidenced by their X EQ values of ≤0.2% at ≤300 °C (Table S2). Previous articles also disregarded to consider N 2 as a product ( vide infra ), overlooked elementary steps concerning the recovery of catalyst surfaces post their poisoning with AS/ABS, and missed to clarify the major surface site/elementary step in dictating − r AS/ABS . − Herein, convincing elementary stages are suggested to account for AS degradation by way of the generation of ABS or ammonium sulfamate (NH 4 NH 2 SO 3 ) as an intermediate (Figure C) . All the steps involved are viable in the thermodynamic aspect ( X EQ values of ∼100% at ≤300 °C; Tables S3 and S4) and can undergo catalytic dehydration/deamination to produce ammonium pyrosulfate ((NH 4 ) 2 S 2 O 7 ) as an intermediate (Figure C–E).…”

Comprehensive Review of Sealant Materials for Leakage Remediation Technology in Geological CO2 Capture and Storage Process

“…It showed that conventional Portland cement had a compressive strength decrease of 21.43%, while calcium-aluminate cement was only 5.16%. In addition, weight control agents, such as fly ash, , slag, , nanoparticles (e.g., microsilicon), ,− resins, , polymers, and many other swelling agents , can be added to adjust the CaO percentage, improve the cement density, and obtain better cement strength. In recent years, there have been many CO 2 -resistant additives developed to protect conventional Portland cement from acidic corrosion. − Vorderbuggen et al and Doan et al developed a cement additive (e.g., hydroxyethylcellulose, methyl hydroxyethylcellulose, and carboxymethyl hydroxyethyl cellulose) that can create an insoluble barrier when it encounters an acid attack. Laboratory tests showed that this additive performed well under specific pressure and temperature in brines saturated with CO 2 for weeks.…”

“…It showed that conventional Portland cement had a compressive strength decrease of 21.43%, while calcium-aluminate cement was only 5.16%. In addition, weight control agents, such as fly ash, , slag, , nanoparticles (e.g., microsilicon), ,− resins, , polymers, and many other swelling agents , can be added to adjust the CaO percentage, improve the cement density, and obtain better cement strength.…”

Technoeconomic Analysis of a Brine Purification Process─Combined Carbon Dioxide Mineralization and Hydromagnesite Recovery

“…In order to meet the economic and environmental requirements, industrial wastes containing magnesium, calcium, iron, and so forth can be used as alternatives mineral alkaline sources. They are readily and cheaply available, and their feasibilities have been validated in red gypsum, − steelmaking slag, , desulfurization slag, coal fly ash, − phosphogypsum, , carbide slag, and so forth.…”