(86a) Selective and Efficient Valorization of Industrial Wastes Via Carbon Mineralization

Industrial waste treatment and utilization can efficiently address perspectives of sustainability and cost-effectiveness, in the context of green chemistry and engineering. Specifically, the integrated process of CO₂ mitigation technologies and valuable materials production is appealing to the industrial sectors, and is the subject of our presentation. In our studies, we used construction and demolition waste, steel slags and coal fly ash to develop multi-stage of processes to selectively extract out Ca first from waste materials by acid leaching and followed by indirect mineralization to produce high purity of calcium carbonates. We describe how vaterite, aragonite and calcite can be formed with controlled operating processes. Blaze900 probe from BlazeMetrics was integrated with the reactor to monitor the particle size distribution and the shape variations of particles/carbonates in real-time which provided optical information facilitating us to better understand the mechanisms of the leaching and crystallization processes. Multi-step of precipitation of impurities, prior to carbonation, was developed to improve the quality of carbonates by removing impurities from dissolution process (Fe, Al and Si). We applied elements of this process to a larger scale reactor (30L) after optimizing the lab-scale operating conditions and we aim to fix a large amount of CO₂ under mild conditions and produce high-value products. To achieve a more sustainable process, salt electrolysis is used to produce acid and base to offset chemical costs. Finally, we report using solid residues as supplementary cementitious materials in the construction materials.