Flow-through leach testing applied to stabilized/solidified wastes

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:549392

Butcher, E J; Cheeseman, C R; Sollars, C J; Perry, R ^[1]

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1. Imperial Coll., London (United Kingdom). Centre for Environmental Control and Waste Management

One of the fundamental requirements for assessing the suitability of cement-based Stabilization/Solidification as a method for the safe disposal of hazardous materials is the manner in which they will release contaminants over an extended period of time. In this paper the leaching of a synthetic Stabilized/Solidified waste, of composition similar to wastes produced from a commercial process in the United Kingdom are investigated under conditions in which leachant flows through the connected porosity of the sample. The leaching of Zn, Cd, Hg, Pb, Cu, Ni, Fe and Cr has been determined using a modified triaxial cell (flexible wall permeameter). Analysis of unleached solidified waste samples using XRD indicated retardation of conventional cement hydration reactions. The principal crystalline phases observed were ettringite and calcite. Leaching carried out using RO purified water used to simulate a mono-disposal situation, indicated that sufficient buffering capacity remained in the solidified materials to limit the release of all elements except Hg to less than 1% of the total. In a second series of experiments acetic acid, designed to simulate co-disposal conditions was passed through samples. The acid buffering capacity was found to be insufficient to allow retention of metals after only 50 sample volumes.

• OSTI ID: 549392
• Report Number(s): CONF-931119--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CADMIUM
CEMENTS
CHROMIUM
COPPER
HAZARDOUS MATERIALS
IRON
LEACHING
LEAD
MERCURY
METALS
NICKEL
SOLIDIFICATION
STABILIZATION
WASTE FORMS
WASTE PROCESSING
ZINC