A1 Journal article (refereed), original research

Removal of hazardous trace elements from recovery boiler fly ash with an ash dissolution method


Open Access publication

Publication Details
Authors: Kinnarinen Teemu, Golmaei Mohammad, Jernström Eeva, Häkkinen Antti
Publisher: Elsevier
Publication year: 2018
Language: English
Related Journal or Series Information: Journal of Cleaner Production
Journal acronym: JCP
Volume number: 209
Start page: 1264
End page: 1273
Number of pages: 10
ISSN: 0959-6526
eISSN: 1879-1786
JUFO-Level of this publication: 2
Open Access: Open Access publication
Location of the parallel saved publication: http://urn.fi/URN:NBN:fi-fe2018111247870

Abstract

The presence of hazardous trace elements (HTE) in the chemical recovery cycle of Kraft pulp mills is the
main obstacle for the utilization of the inorganic residues of the process. Electrostatically precipitated
(ESP) recovery boiler fly ash (RBFA), consisting mainly of sodium sulfate Na2SO4, is a solid side stream
where HTE are concentrated. Unlike most other ashes, RBFA is to a great extent water-soluble. A novel
reverse leaching method, based on the dissolution behavior of RBFA in water, is introduced in this paper.
The method is founded on the use of an appropriate liquid/solid mass ratio and a favorable pH, which
together contribute to the formation of a small and readily settling solid residue where almost all HTE are
concentrated. This paper focuses on evaluating the influence of the treatment conditions on HTE
removal, energy consumption and material losses. The results of this study show that the removal efficiency
of the investigated HTE and other analyzed metals was excellent under alkaline conditions, the
apparently suitable pH range for the removal of most of these metals being approximately 11.7-12.2.
Lead was observed to be the most difficult HTE to remove: the highest obtained degree of removal of Pb
was 89%. The removal rate of Cd and Zn was approx. 100% within the mentioned pH range.


Last updated on 2019-13-03 at 12:00