A novel dry treatment for municipal solid waste incineration bottom ash for the reduction of salts and potential toxic elements

The main obstacle to bottom ash (BA) being used as a recycling aggregate is the content of salts and potential toxic elements (PTEs), concentrated in a layer that coats BA particles. This work presents a dry treatment for the removal of salts and PTEs from BA particles. Two pilot-scale abrasion units (with/without the removal of the fine particles) were fed with different BA samples. The performance of the abrasion tests was assessed through the analyses of particle size and moisture, and that of the column leaching tests at solid-to-liquid ratios between 0.3 and 4. The results were: the particle-size distribution of the treated materials was homogeneous (25 wt % had dimensions <6.3 mm) and their moisture halved, as well as the electrical conductivity of the leachates. A significant decrease was observed in the leachates of the treated BA for sulphates (44%), chlorides (26%), and PTEs (53% Cr, 60% Cu and 8% Mo). The statistical analysis revealed good correlations between chloride and sulphate concentrations in the leachates with Ba, Cu, Mo, and Sr, illustrating the consistent behavior of the major and minor components of the layer surrounding BA particles. In conclusion, the tested process could be considered as promising for the improvement of BA valorization.

Schlagworte

bottom ash

dry treatment

incineration

municipal solid waste

potential toxic elements

salts

DDC Class

600: Technik

620: Ingenieurwissenschaften

Projekt(e)

BASH-TREAT-Optimierung der Rostaschebehandlung für eine verbesserte Rückgewinnung von Metallen und Wertstoffen aus der Feinfraktion-Teilprojekt 1: Qualitätssicherung und weitergehende Entwicklung der Aufbereitungstechnik.

Publikationsfonds 2021

Funding Organisations

Bundesministerium für Bildung und Forschung

More Funding Information

The authors would like to acknowledge the financial support to the project BASH-Treat (ID 157) provided by the ERA-MIN2 Research & Innovation Programme on Raw Materials to Foster Circular Economy, by the German Federal Ministry of Education and Research (BMBF, FKZ 033RU005 A-C) and by the Italian Ministry of University and Research (MIUR). The authors are thankful to project partners Heidemann Recycling GmbH and Sysav Utveckling AB.

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

materials-14-03133-v2.pdf

Size

3.66 MB

Format

Adobe PDF

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A novel dry treatment for municipal solid waste incineration bottom ash for the reduction of salts and potential toxic elements