Immobilization of toxic metals of industrial waste via low temperature vitrification

Abstract

Wastes generated from metal finishing and galvanizing processes, have been vitrified at 800-950<span style="font-size:9.0pt;font-family:Symbol;mso-ascii-font-family: " times="" new="" roman";mso-hansi-font-family:"times="" roman";mso-char-type:symbol;="" mso-symbol-font-family:symbol"="" lang="EN-US">°C after heating of waste, clay and sodium carbonate in their different proportions. Observed results indicate that a composition containing 1:1:2 ratio of waste, sodium carbonate and clay attains a clear vitrification at 950<span style="font-size:9.0pt;font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";="" mso-hansi-font-family:"times="" roman";mso-char-type:symbol;mso-symbol-font-family:="" symbol"="" lang="EN-US">°C. TCLP analysis of the leachates obtained from the vitrified masses of different wastes indicates the leachability of Cr, Cu, Zn and Pb becomes far below from their threshold values. Decrease of waste content and increase of sodium carbonate in the mixture has shown a further decrease of vitrification temperature. However, compressive strength of the vitrified mass is found to reduce considerably with the increase of sodium carbonate content in the vitrifying compositions.

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