Leach characterization of hazardous waste stabilized with Portland cement
The process of cement matrix solidification of a hazardous inorganic waste mixture containing As(2)O(3), CrCl(3).6H(2)O, K(2)CrO(4), CdCl(2), HgO and Pb[(NO)(3)](2) compounds has been evaluated by performing leach experiments both in static and dynamic water conditions. Improved physical characteristics of the matrix were observed when 9% of waste was blended in cement. In the static leach test the release concentrations of As(III), Cd(II) and Cr(VI) metals were substantially reduced compared with previous investigations in which a single compound of each of As(III), Cd(II), Cr(III) and Cr(VI) was immobilized separately in cement. In all cases the leachate concentrations of As(III), Cd(II) and Cr(III) gave a result much below their permissible limits as reported in the literature for drinking water quality. Chromium (III) was found to be completely stabilized in the cement matrix probably as Cr(OH)(3).nH(2)O. The hydrolysed compound Cr(OH)(3).nH(2)O is believed to influence also the leaching rates of other metals by limiting their ionic mobility within the solidified matrix. The kinetic release of mercury was a linear function of time so this metal has been assumed to be only physically adsorbed in cement matrix. The amount of waste incorporated in cement presents no adverse effects on the matrix durability measured by calcium release, which is a main cement constituent.
Bibliographic Reference: EUR 12176 EN (1989) MF, 26 pp., ECU 4, blow-up copy ECU 5
Record Number: 198910504 / Last updated on: 1994-12-01
Original language: en
Available languages: en