Leaching optimization of municipal solid waste incineration ash for resource recovery: A case study of Cu, Zn, Pb and Cd
Journal article, 2016

Ash from municipal solid waste incineration (MSWI) may be quite cumbersome to handle. Some ash fractions contain organic pollutants, such as dioxins, as well as toxic metals. Additionally, some of the metals have a high value and are considered as critical to the industry. Recovery of copper, zinc and lead from MSWI ashes, for example, will not only provide valuable metals that would otherwise be landfilled but also give an ash residue with lower concentrations of toxic metals. In this work, fly ash and bottom ash from an MSWI facility was used for the study and optimization of metal leaching using different solutions (nitric acid, hydrochloric acid and sulfuric acid) and parameters (temperature, controlled pH value, leaching time, and liquid/solid ratio). It was found that hydrochloric acid is relatively efficient in solubilizing copper (68.2 ± 6.3%) and zinc (80.8 ± 5.3%) from the fly ash in less than 24 h at 20 °C. Efficient leaching of cadmium and lead (over 92% and 90% respectively) was also achieved. Bottom ash from the same combustion unit was also characterized and leached using acid. The metal yields were moderate and the leachates had a tendency to form a gelatinous precipitate, which indicates that the solutions were actually over-saturated with respect to some components. This gel formation will cause problems for further metal purification processes, e.g. solvent extraction.

Copper

MSWI ash

Cadmium

Lead

Hazardous metals

Acidic leaching

Waste treatment

Zinc

Author

Jinfeng Tang

Industrial Materials Recycling

Britt-Marie Steenari

Industrial Materials Recycling

Waste Management

0956-053X (ISSN) 1879-2456 (eISSN)

Vol. 48 315-322

Driving Forces

Sustainable development

Subject Categories

Chemical Engineering

DOI

10.1016/j.wasman.2015.10.003

PubMed

26463013

More information

Created

10/7/2017