Thermoplastic Processes

Bitumen stabilization techniques (including bitumen, paraffin and polyethylene) were developed for use in radioactive waste disposal and later adapted for handling industrial wastes. In a bitumen process, the waste is dried and then mixed with bitumen, paraffin or polyethylene (usually at temperatures greater than 100°C). The mixture solidifies as it cools, then is placed in a container, such as a steel drum or a thermoplastic coating, before disposal.

A variation of the bitumen process uses an asphalt emulsion that is miscible with the wet sludge. This process can be conducted at a lower temperature than a bitumen process. The emulsion-waste mixture must be dried before disposal.

The type of waste sludges that can be fixed with bitumen techniques is limited. Organic chemicals that act as solvents with bitumen cannot be stabilized. High concentrations of strong oxidizing salts such as nitrates, chlorates, or perchlorates will react with bitumen and cause slow deterioration.

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