Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.592062
Title: Leaching of cement-stabilised solid waste
Author: Andac, M.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 1997
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Abstract:
The physical, chemical and leaching properties of municipal solid waste incinerator (abbreviated MSWI) fly ash itself and the long term leaching properties and leaching mechanisms of stabilised MSWI-fly ash in cement systems were analysed. MSWI-fly ash is a complex material which consists of crystalline phases including NaCl, KCl, CaSO4, SiO2, glassy silicates and also an amorphous organic phase. The MSWI-fly ash has a relatively high content of toxic metals, mainly Zn and Pb. The leaching properties of these elements from the ash depends on leachate pH as well as the leach test method. The most leachable major elements are alkali metals and calcium. The toxic metals are also liable to be leached in disposal situations. Ordinary Portland Cement (OPC) and Calcium Sulfoaluminate Cement (CSA) were used for stabilisation of MSWI-fly ash. The ash is partly pozzolanic in the cement systems and affects each type of cement differently. Inclusion of 10% ash in OPC matrices reduces the formation of Ca(OH)2. In a CSA matrix, formation of AFm and AFt reduced and also new compound or compounds form after 60 days curing. In CO2 bubbled water, the leaching rate of elements from 10% MSWI-fly ash containing cements, especially Zn and Pb, change with time as well as with ongoing hydration. The extension of curing time for CSA + 10% ash paste degrades the matrix retention of Pb: the leached percent of Pb increases from 0.0009 to 0.0023% with extension of curing from 7 to 60 days. But the percent of Zn leached decreases with extension of curing time: 0.087 to 0.0157%. On the other hand the leaching percent of Zn and Pb from OPC + 10% ash decreases with curing time. Generally in short term curing, the leached percent of elements from an OPC + 10% ash paste is higher than from a CSA + 10% ash paste.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.592062  DOI: Not available
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