Valorization of Metallurgical Slag for the Treatment of Water Pollution: An Emerging Technology for Resource Conservation and Re-utilization

Ironmaking and Steelmaking Slags as Sustainable Adsorbents for Industrial Effluents and Wastewater Treatment: A Critical Review of Properties, Performance, Challenges and Opportunities

“…The findings from various studies (Table 5) affirm the proposition that ironmaking and steelmaking slags can be considered mostly mesoporous, low-cost adsorbents. Ironmaking and steelmaking slags have a mesoporous and amorphous structure with a typically low specific surface area of less than 10 m 2 g −1 [25,58,63,67,69,70,74], even though relatively high values of up to 32 m 2 g −1 have been reported by Feng et al [71] and Zahar et al [73] (Table 5). Runtti et al [74] also reported relatively higher values.…”

“…Several studies have investigated the effect of the degree of crystallinity on the absorptive capacity of ironmaking and steelmaking slags. The findings indicate that an increase in the amount of crystalline phases such as gehlenite (Ca 2 Al 2 SiO 7 ), larnite (Ca 2 SiO 4 ), bredigite (Ca 5 MgSi 3 O 12 ), merwinite (Ca 3 Mg(SiO 4 ) 2 ) and akermanite (Ca 2 MgSiO 7 ), among others, significantly increases the adsorption capacity of cations and anions from solution [15,19,25,57,58]. However, since these phases may not always be uniformly present in the post-solidification state, several studies have explored in detail the impact of activation and modification on the adsorption capacities of slags [42,57,[59][60][61][62][63][64][65][66].…”

“…However, the disposal of slags in landfills creates long-term environmental challenges [22][23][24]. In order to mitigate the anthropogenic effects of process slags, it is therefore imperative to explore alternative utilisation options and to reduce the amounts that end up in landfills [22][23][24][25]. Thus, the alternative use of slags as sustainable and low-cost adsorbents is one such approach that can increase the valorisation potential of these materials [3,4,[22][23][24][25].…”

“…In fact, the World Steel Association [37] estimates that over 400 million tonnes of ferrous slags are produced annually. Thus, exploring the use of these slags as low-cost adsorbents is beneficial in reducing the volumes of landfilled slags, thereby mitigating the storage and toxicity concerns associated with their disposal [22,23,25]).…”

Preface to the 5th International Slag Valorisation Symposium: From Fundamentals to Applications

“…Mercado-Borrayo et al [4] summarized and discussed the studies dealing with the use of metallurgical slag to remove inorganic, organic, and biological contaminants from water, originating from industrial activities or natural wells. The strategy of these studies, the suggested mechanisms of removal and the general trends in effectiveness of steel, iron, or copper slag as removing agent or catalyst are addressed.…”