liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Extraction of Heavy Metals from Fly Ash using Electrochemical Methods
Linköping University, Department of Physics, Chemistry and Biology.
2010 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

In today’s society large quantities of waste is produced. In Sweden this is reused as fuel for incineration processes where electricity and district heating are generated. However, during this process two hazardous by-products are formed, namely slag and fly ash. These contain relatively high concentrations of heavy metals, which make them harmful to the environment if not taken care of, but also make them valuable resources if the metals could be extracted and reutilized.

One possible way to extract metals from the waste products is to use electrochemical methods. In order to implement these techniques on an industrial scale, there are several parameters that have to be considered. One important parameter is the choice of material of the electrode, which needs to have a large surface area, a high chemical inertness and electrical conductivity, and preferably also a reasonable price. A material that fulfills these qualifications is reticulated vitreous carbon (RVC), and therefore the extraction efficiency of this porous material has been evaluated in this thesis. Studies were also performed to evaluate how several other parameters affected the extraction efficiency, since this does not rely on the choice of electrode material alone.

The results showed that RVC is suitable as electrode material for efficient metal extraction from fly ash. The most efficient electrode combination was RVC with a pore size of 10 pores per linear inch as working electrode, stainless steel as counter electrode, and Ag/AgCl as reference electrode. Both the amperometric and galvanostatic experiments extracted equal amounts of copper within the same time interval, which means that the choice of using either controlled potential or controlled current for an efficient extraction of copper was not of significant importance. The mass transfer rate for copper was 0.12 mg·h-1·cm-2 in both methods, where an electrolyte of 200 ml was used with an initial copper concentration of 50 mg/l. Regarding stirring of the electrolyte, circulation in the solution is an advantage, but not critical for an efficient reduction. The extraction efficiency for one particular metal did not seem to be affected by the presence of other metals in the electrolyte. It was also shown that a selective extraction of metals was possible by applying different potentials. Lastly, an experiment with fly ash was performed, with the optimal conditions and electrode combination based on the previous experiments. This yielded a mass transfer rate of 0.59 mg·h-1·cm-2 for zinc using an electrolyte of 200 ml, which initially contained 595 mg/l of zinc.

Place, publisher, year, edition, pages
2010. , 44 p.
Keyword [en]
Municipal Solid Waste, Fly Ash, Reticulated Vitreous Carbon, Electrochemistry, Metal Extraction
National Category
Natural Sciences
URN: urn:nbn:se:liu:diva-64361ISRN: LITH-IFM-A-EX--10/2381--SEOAI: diva2:389742
2010-12-21, Planck, Fysikhuset LiU, Linköping, 13:00 (Swedish)
Physics, Chemistry, Mathematics
Available from: 2011-01-20 Created: 2011-01-20 Last updated: 2011-01-20Bibliographically approved

Open Access in DiVA

fulltext(1342 kB)928 downloads
File information
File name FULLTEXT01.pdfFile size 1342 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Department of Physics, Chemistry and Biology
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 928 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 212 hits
ReferencesLink to record
Permanent link

Direct link