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Extruder/melter
WHC-SD-W100-TI-003 Rev. 0
In this process, the waste and matrix material are added to a screw-type
extruder. The mechanical power applied to the extruder screws heats and melts
the matrix, mixing it with the waste and evaporating any water that may be
present. Some extruders also use external heating. The mixture is then
transferred to the disposal container and allowed to cool and solidify.
Polymer Encapsulation
Polymer encapsulation processes require facilities to store, transfer, and mix
the organic liquid reactants with the waste. Control of volatile vapors from
the process is also required.
Liquid handling
The raw ingredients for thermosetting polymers are liquid organic chemicals.
These chemicals may be flammable but can be handled with conventional
processing equipment.
Tanks & pumps
Carbon steel tanks and centrifugal pumps are suitable for most applications.
Some organic acids ( promotors or catalysts) may require stainless steel
equipment.
Pipes & val'ves
Materials are transferred through piping and control valves. Fugitive
emissions from piping systems must be minimized.
Vent vapor control
Control of flammable or corrosive organic vapors from tank vents is required
for raw materials storage systems.
In-drum mixing
In-drum mixing can be used when the waste is granular, powdery, or a
reasonably fluid material. In-drum mixing methods are similar to those used
for cementation.
High-shear mixing
The organic binder material is charged to the drum. The waste is added while
the binder is mixed with a propeller type mixer. When mixing is complete, the
mixer is withdrawn and excess binder is flung off into an empty drum.
Lost-paddle mixer
The collapsible mixer is inserted tkrough-the bung hole of the drum.
- - Following mixing, the paddle remains in the drum.
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