Mechanisms of metal containment resulting from the solidification of a commercially produced stabilized waste

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

OSTI ID:549375

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

The stabilized filter cake produced at a commercial stabilization/solidification plant, which treats a wide variety of inorganic solid wastes and effluents, has been characterized, and subsequently solidified by adding increasing amounts of cement and fly ash. This stabilized waste interacts with the cementitious additives so that the normal products of hydration are no longer produced. a solidified material is, however, still formed, and ettringite is the main crystalline product. The degree of chemical containment has been determined by completing single extraction batch leach tests under increasingly aggressive conditions. Results indicate that hazardous heavy metals are well retained by the solidified wastes, while they are readily leached from the stabilized filter cake. The concentrations of metals released from the stabilized waste and the solidified materials exhibit the same behavior as a function of leachate pH. This demonstrates that a major effect of the cementitious additives is to change the composition of the leaching fluid. The addition of solidified wastes containing increasing amounts of cementitious additives is to an acidic leachant causes Ca{sup 2+} to leach at a concentration determined by the acidity of the leachant. Mixes containing low additions of cementitious additives cannot release sufficient Ca{sup 2+}, the leachate remains acidic, and heavy metals present in the waste are able to leach.

• OSTI ID: 549375
• Report Number(s): CONF-931119--
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
CEMENTS
FLY ASH
HAZARDOUS MATERIALS
LEACHING
METALS
SOLIDIFICATION
WASTE PROCESSING