The more economically viable and environmentally sustainable approach for treating the by-products of coal combustion from thermal power plants entails their collective disposal as opposed to individual disposal methods. This aligns with pertinent EU directives and domestic regulations, ensuring compliance with established standards while optimizing resource utilization and minimizing environmental impact. This study evaluated the resistance to wind erosion of the binding properties of a mixture (fly ash (FA), bottom ash (BA), and additives) using an indoor wind tunnel under simulated ambient conditions. Investigations of the mutual impact of ash, bottom ash, and additives (CaO and Ca(OH)₂) with a certain percentage of water were carried out with eighteen samples. The samples consisted of the water at six addition rates 5, 8, 10, 15, 20, and 25% (w/w), and additive at three addition rates (1, 2, and 3% (w/w). Based on the obtained results, the optimal ratios of additives (3% (w/w)) and water (15% (w/w)) were determined. Prior to the wind tunnel experiments, and according to the different addition rates of additives and water, eight samples were prepared with different addition rates of ash. The mass concentrations of suspended particles (PM₁₀) and total suspended particles (TSPs) in these samples were measured at three distinct wind velocities: 1 m/s, 3 m/s, and 5 m/s, respectively. The results indicate that the samples containing the optimal content of additives and water demonstrate a maximum increase in PM₁₀ emission zero values of no more than 1.9 times. This finding can be considered satisfactory from the standpoint of environmental protection.

Remediating and recovering valuable metals from metallurgical slags is a critical challenge and opportunity for sustainable resource management in the metal extraction industry. This study investigates a process to simultaneously recover nickel, copper, and cobalt from nickel converter slag from the Sudbury region, Canada, using carbon- and iron-based reducing agents. Experimental results show that, without additives, performing reduction settling at 1300 °C, a process similar to metal extraction from ore concentrates, yielded 62 wt% recovery of valuable metals, while after adding reducing additives, over 90% of entrained valuable metals were efficiently coalesced into a matte phase within one hour, significantly reducing the hazardous metal content in the residual slag leaving mainly iron and silicon oxides, which are stable and environmentally benign. X-ray diffraction and SEM-EDS analyses show that after treatment, the dominant phases in the residual slag are fayalite (Fe₂SiO₄) and glassy silicates, with almost no detectable sulfide or metallic inclusions or other leachable metal-bearing phases. Estimated total cost to increase and maintain slag temperature at 1300 °C for 1 h is $44.50 per tonne. The exothermic reaction of ferrosilicon with slag provides 14.60 kWh/tonne of energy, reducing the need for external heating, while the value of recovered metals is about 10 times higher than the estimated capital, processing, and transportation costs of the additional process treatment. An efficient and sustainable approach to recovering valuable metals from nickel slag, using innovative chemistry and process integration, delivered high metal recovery, reduced environmental impact, and clear economic benefits. The proposed approach aligns with the United Nations Sustainable Development Goals, as outlined in the document ‘Transforming Our World: the 2030 Agenda’, supports circular economy principles, enhances resource efficiency, and offers a practical pathway for remediating legacy slag deposits in existing metals extraction facilities.