Reduction of steel slag leachate pH via humidification using water and aqueous reagents

The utilization of alkaline wastes in passive carbon capture and sequestration: Promises, challenges and environmental aspects

“…For example, pH has variable effects on the carbonation process. Lower pH increases metal leaching thereby increases the reactants' concentrations while higher pH promotes carbonates precipitation (Azdarpour et al, 2015;Chen et al, 2019). While increasing the temperature is associated with decreased CO2 solubility in the aqueous solution , increasing the temperature from 10 ºC to 40 ºC was found to positively correlate with cations release from alkaline wastes, and the decreased solubility of CO2 did not represent a limiting step (Assima et al, 2014a(Assima et al, , 2014b.…”

“…Alkaline pretreatment has been proposed to enhance leaching behavior and carbonation capacity of slag (Chen et al, 2019). The proposed carbonation enhancement method involves pretreating slag with alkaline solution since, as shown in a previous study (You et al, 2011) and illustrated in Fig.…”

“…7, when slag comes into contact with water, a dense layer of aluminosilicates may form and inhibit the carbonation reaction. This layer can be broken down upon the addition of alkaline sources and then converted to hydrated calcium phases, thereby producing more phases that can be carbonated to CaCO3 (Chen et al, 2019;Matsushita et al, 2000).…”

“…It was demonstrated that the amount of CO2 captured within the pretreated slag was higher, as demonstrated in the calcite formation which was 17.05 and 50.68 mg CaCO3 g -1 slag, for the raw slag and pretreated slag, respectively. Additionally, a waste management practice was proposed to enhance the carbonation, reduce leachate pH and allow for reactivity enhancement of the slag (Chen et al, 2019). Portrayed in Fig.…”

Biomethane production from anaerobic co-digestion and steel-making slag: A new waste-to-resource pathway

“…Steel-making slag, a by-product from steel production, is a potential alkaline adsorbent for CO 2 capture from biogas due to the presence of free basic oxides, such as CaO and MgO in its chemical composition (Baciocchi et al, 2016;Chen et al, 2019;Heiderscheidt et al, 2020). Apart from the potential production of biomethane with low costs, the use of steel-Journal Pre-proof J o u r n a l P r e -p r o o f making slag for carbon sequestration brings other benefits.…”