Municipal solid waste (MSW) and refuse-derived fuel (RDF) incineration generate over 20 million tons of residues annually in the EU. These include bottom ash (IBA), fly ash (FA), and air pollution control residues (APCr), which pose significant environmental challenges due to their leaching potential and hazardous properties. While these residues contain valuable metals and reactive mineral phases suitable for carbonation or alkaline activation, chemical, techno-economic, and policy barriers have hindered the implementation of sustainable, full-scale management solutions. Accelerated carbonation technology (ACT) offers a promising approach to simultaneously sequester CO₂ and enhance residue stability. This review provides a comprehensive assessment of waste incineration residue carbonation, covering 227 documents ranging from laboratory studies to field applications. The analysis examines reactor designs and process layouts, with a detailed classification based on material characteristics, operating conditions, investigated parameters, and the resulting pollutant stabilization, CO₂ uptake, or product performance. In conclusion, carbonation-based approaches must be seamlessly integrated into broader waste management strategies, including metal recovery and material repurposing. Carbonation should be recognized not only as a CO₂ sequestration process, but also as a binding and stabilization strategy. The most critical barrier remains chemical: the persistent leaching of sulfates, chromium(VI), and antimony(V). We highlight what we refer to as the antimony problem, as this element can become mobilized by up to three orders of magnitude in leachate concentrations. The most pressing research gap hindering industrial deployment is the need to design stabilization approaches specifically tailored to critical anionic species, particularly Sb(V), Cr(VI), and SO₄²⁻.

Treatments to reduce the leaching of contaminants (chloride, sulfate, heavy metals) into the environment from bottom ash (BA) are investigated, as a function of the ash’s particle size (s). The aim is to make BA suitable for reuse as secondary raw material, in accordance with the legal requirements. Such treatments must be economically feasible and, possibly, have to use by-products of the plant (in this case, steam in excess from the turbine). For the sake of completeness and comparison, carbonation is performed on those BA particle size classes that are not positively responsive to steam washing. BA is partitioned into four different particle size classes (s ≥ 4.75, 4.75 > s ≥ 2, 2 > s ≥ 1 and s < 1 mm, corresponding to 36, 24, 13 and 27 wt%, respectively). In the case of s ≥ 2 mm (60 wt%), steam washing is effective in reducing to under the legal limits the leaching of chlorides, sulfate and heavy metals (Zn, Cu, Cd, Pb). It has been observed that steam washing causes both removal and dissolution of thin dust adherent to the BA’s surface. BA with 2 > s ≥ 1 (~13 wt% of total BA) requires a combination of steam washing and carbonation to achieve a leaching below the legal limits. The finest BA fraction, s < 1 mm (~27 wt% of total BA), is treated by carbonation, which reduces heavy metals leaching by 85%, but it fails to sufficiently curb chlorides and sulfates.

This study investigates the reactivity of municipal solid waste incineration residues to aqueous carbonation, focusing on CO₂ absorption rates, uptakes, and heavy metal (HM) leachability. Various combinations of boiler, electrofilter, and bag filter residues were assessed under typical incineration conditions. Bag filter residues from lime-sorbent plants exhibited the highest CO₂ uptake (244.5 gCO₂/kg), while bottom ash (BA) fine fraction, boiler/electrofilter fly ash (FA), and other mixed air pollution control residue (APCr) demonstrated uptakes of 101, 0, 93, and 167 gCO₂/kg, respectively. Carbonation kinetics revealed that high calcium content FA and APCr, followed similar CO₂ absorption trends. Notably, BA carbonation was predominantly driven by Ca-aluminates rather than lime. Carbonation reduces leaching of Al, As, Cd, Co, Cu, Ni, Pb and Zn compared to water washing, though significant concerns arise with anions such as Sb and Cr. In BA, critical behaviours of Cr, Mn, and Fe were observed, with Cr leaching likely controlled by Fe-Mn-Cr oxide particle dissolution. These findings highlight the potential of integrating enhanced metal recovery (EMR) through density or magnetic separation in BA prior to carbonation to reduce HM leaching and recycle critical metals (Ag, Cu, Cr, Ni, Mn, etc).

CO₂ sorption–desorption cycles with a methyldiethanolamine (MDEA)/piperazine (PZ) blend have been performed with a rotoevaporator. Similar to other CO₂ separation technologies, the heating involved in MDEA/PZ solvent regeneration is the most energy-intensive step in the overall CO₂ separation process. Thus, this study investigated the desorption kinetics under low-pressure (<200 mbar) and low-temperature conditions in the range from 308 to 363 K with the aim of reducing costs. The CO₂ desorption time to unload the samples from ~2.35 mol/kg to below the threshold of 1 mol/kg was reduced from 500 s at 333 K to 90 s at 363 K. The Avrami–Erofoyev model was found to fit the experimental kinetic data accurately. The Arrhenius law calculations provided an activation energy of the CO₂ desorption process equal to 76.39 kJ/mol. It was demonstrated that the combination of a pressure reduction and the increase in temperature resulted in an enhancement of the desorption kinetics, especially at low temperatures. The combined effect of these two factors resulted in higher desorption kinetics compared to the individual effects of either factor alone. Solvent regeneration at a low temperature was demonstrated to be a valid option when coupled with pressure reduction.