A mini-review of heavy metal recycling technologies for municipal solid waste incineration fly ash

Abstract

This mini-review article summarizes the available technologies for the recycling of heavy metals (HMs) in municipal solid waste incineration (MSWI) fly ash (FA). Recovery technologies included thermal separation (TS), chemical extraction (CE), bioleaching, and electrochemical processes. The reaction conditions of various methods, the efficiency of recovering HMs from MSWI FA and the difficulties and solutions in the process of technical development were studied. Evaluation of each process has also been done to determine the best HM recycling method and future challenges. Results showed that while bioleaching had minimal environmental impact, the process was time-consuming. TS and CE were the most mature technologies, but the former process was not cost-effective. Overall, it has the greatest economic potential to recover metals by CE with scrubber liquid produced by a wet air pollution control system. An electrochemical process or solvent extraction could then be applied to recover HMs from the enriched leachate. Ongoing development of TS and bioleaching technologies could reduce the treatment cost or time.

Advances and Outlook of Heavy Metal Treatment Technology from Municipal Solid Waste Incineration Fly Ash: A Review

“…The conventional calcined thermal separation process is characterized by low heavy metal separating effect and high-energy consuming. By comparison, all three other methods of thermal separation achieved removal rates above 90%, used additives to facilitate the volatilization on heavy metals, and lowered the calcining temperature. , As a result, the use of additives presents several challenges. Thermal separation of chlorine provides excellent removal of heavy metals with less energy consumption thanks to the use of chlorinating agents, and Chan et al reported complete volatilization of Zn, Pb, Mn, and Cu at 900 °C in a 2% Cl 2 atmosphere.…”

Research and Innovation Needs for the Waste-To-Energy Sector towards a Net-Zero Circular Economy

“…Therefore, the objective of the waste-to-energy and materials approach (Figure 1) is to devise solutions that make the extraction of valuable elements from FA economically attractive. Currently, several techniques, mainly of a thermal or hydrometallurgical nature [51], are under study. The greatest economic potential likely lies in the integration with other operations conducted at the WtE plant: for instance, zinc recovery via acid leaching by reusing effluents from wet flue gas cleaning systems, of which the feasibility at an industrial scale was demonstrated recently [52,53].…”

Resistance and durability of fly ash based geopolymer for heavy metal immobilization: properties and mechanism

“…The main treatment methods for FA now include safe disposal in landfills, solidification/stabilization (S/S), separation and extraction, and heat treatment. 5 Out of the various methods used in China for disposing of FA, the S/S technology is considered the most prominent. 6 S/S is a procedure that entails the amalgamation of a fixing agent with an immobilization agent, followed by a reaction conducted under precise conditions to generate a solidified matrix.…”