Rubber desolventizing process

Figure 17. Process flow scheme for continuous evaporation in a rubber desolventizing process.

Ground shrub was mixed with a dilute caustic solution that coagulated the rubber and resin (extractable low molecular weight secondary metabolites) as solid particles called worms . The worms were skimmed from the surface, deresinated with an acetone wash, dried, and compressed into bales. Alternatively, the deresinated rubber was dissolved in a nonpolar solvent such as hexane. Antioxidant was added to the hexane cement prior to filtration and desolventization. The weaknesses of flotation processing included the rate-limiting nature of the deresination step and the need to dispose of large volumes of caustic flotation medium. 

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