Research on the recovery and purification of lead ions from the aqueous leachate of municipal solid waste incineration fly ash.

The incineration of municipal solid waste generates a significant amount of MSWIFA, which poses environmental risks due to its high chlorine and lead content, hindering its resourceful utilization. Firstly, water washing is used to remove chlorine and heavy metals from the MSWIFA, followed by a combination of CO2 aeration and acid leaching to recover lead from the aqueous leachate and purify the lead in the CO2 precipitate. According to the research results, the MSWIFA from waste incineration was pre-treated with a single water washing at 500 r/min with a liquid-to-solid ratio of 5 for 10 min. It was found in the experiment that when the MSWIFA leachate was aerated with CO2 at a flow rate of 100 mL/min for 60 min, the recovery rate of lead ions reached 81.77%. Furthermore, when the CO2 precipitate was leached with 1.5 mol/L hydrochloric acid, only 0.53% of calcium ions remained un-leached in the precipitate phase, while the lead ions retained reached 70.01%, significantly improving the purity of lead ions in the CO2 precipitate.Implications: Municipal solid waste incineration fly ash (MSWIFA) contains high chlorine and lead, limiting its reuse. This study combined water washing (5:1 liquid-solid ratio, 500 rpm, 10 min) with CO2 aeration (100 mL/min, 60 min) and acid leaching (1.5 mol/L HCl) to remove Cl- and recover Pb2+. CO2 aeration achieved 81.77% Pb2+ recovery, while HCl leaching retained 70.01% Pb2+ in the precipitate, reducing Ca2+ residue to 0.53%. The process effectively purified Pb2+ in the CO2 precipitate, enabling safer MSWIFA utilization. Through this research, it is possible to make effective use of resources and use waste. In line with the current concept of environmental protection.