Abstract: This invention relates to a method for purifying and drying a polymer hydrogel. This invention is based in part upon the discovery that rapid drying of polymer hydrogels can eliminate the problem of unacceptable levels of soluble oligomers caused by prolonged thermal treatment. Rapid drying techniques allow drying hydrogels containing more water than was previously considered possible without a loss in product quality. Furthermore, it was discovered that slurries comprising polymer hydrogels and large quantities of water can be spray dried and that spray drying can be conducted with only minimal oligomer formation.

Abstract: This invention relates to a method for purifying and drying a polymer hydrogel. This invention is based in part upon the discovery that rapid drying of polymer hydrogels can eliminate the problem of unacceptable levels of soluble oligomers caused by prolonged thermal treatment. Rapid drying techniques allow drying hydrogels containing more water than was previously considered possible without a loss in product quality. Furthermore, it was discovered that slurries comprising polymer hydrogels and large quantities of water can be spray dried and that spray drying can be conducted with only minimal oligomer formation.

Abstract: A system for repeatedly supplying a predetermined quantity of solid particulate material, e.g. solid, spherical silicon particles, to a location remote from the area where the particulate material is stored. The system includes a container for storing solid particulate material, a receiving chamber coupled with the container and sized and configured to admit only a predetermined quantity of particulate material from the container, and means for applying at least one stream of a pressurized fluid so as to entrain and transport said predetermined quantity of particulate material from the receiving chamber to the remote location.