Immobilization of Pb in a Geopolymer Matrix
In a geopolymer matrix prepared by mixing a metakaolinite precursor with a solution of potassium hydroxide and silicate, 1 wt% Pb as the nitrate has been immobilized. Under the United States Environmental Protection Agency test protocol the Pb release was less than 5 ppm, the acceptable limit for landfills in the U.S.A. Electron microscopy showed Pb was present in the major amorphous phase and a minor (∼1 vol%) Ca-rich potassium silicate phase. Heating cured samples to several hundred degrees Centigrade was not significantly advantageous for immobilizing Pb.
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Document Type: Research Article
Affiliations: Australian Nuclear Science and Technology Organisation, Menai NSW 2234, Australia
Publication date: 2005-09-01