US Government As Represented by the Secretary of the Army

Other

Lillian D Wakeley

Philip Garcin Malone

William N Brabston

Melvin C Sykes

Judy C Tom

Dennis L Bean

J Pate Burkes

A low-temperature method for producing coated hazardous waste pellets which re used as the aggregate in a concrete wasteform is characterized by combining hazardous waste with a chemically setting organic polymer to form a mixture which is formed into pellets. The pellets are first coated with epoxy and then coated with a silicate-based powder. The liquid concrete-pellet mixture is then placed in molds which can be rotated to concentrate the pellets away from the perimeter of the wasteform. The double-coated hazardous waste pellets have improved bonding when used as a coarse aggregate in a concrete mixture. The resulting wasteform is self-supporting and needs no external container for transportation, storage, or disposal.

Low-temperature method for containing thermally degradable hazardous

High-strength, high-hardness concrete, mortar, or grout is prepared by blending portland cement, water, and aggregate with a source of reactive silica, pouring the concrete mixture into a form, allowing the concrete to cure until it reaches its conventional 28-day strength, and immersing the cured concrete in a solution of alkali metal hydroxide and aluminum nitrate at 60.degree.-110.degree. C. for 3-14 days. Alternatively, the cured concrete may be sprayed with the solution and maintained at 60.degree.-110.degree. C. for 3-14 days. A dense, hard surface layer of alkali metal aluminum silicate is formed, the compressive strength and surface hardness of the concrete is increased, and the water infiltration rate into the concrete is decreased.

Method of increasing density and strength of highly siliceous

A method of containing hazardous and toxic wastes includes the steps of irporating the dried waste, in a salt form, in melted polymer, such as asphalt, and forming the waste salt and asphalt blend into aggregate pellets. The pellets are coated with a powdered coating material that is compatible with a portland cement-based mortar or other cementitious material which is used. The coated particles are mixed with mortar to form a polymer-aggregate concrete and cast into wasteforms for storage or burial. If it is desirable to produce a waste form with a continuous layer of mortar on the exterior of the concrete monolith the mold can be placed on a turntable and spun, or otherwise exposed to a centrifugal force to force the mortar to the outside of the mold. Centrifugal separation is possible because the polymer-waste mixture typically has a specific gravity near 1.5 while that of the cementitious mixture is typically greater than 2.0.

Method of containing and isolating toxic or hazardous wastes

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Vicksburg, MS, United States of America

Lillian D Wakeley