The reversible agglomeration of fine particle plaster of paris

摘要

A method for the reversible agglomeration of fine particles of plaster of Paris (CaSO4.1/2 H2O) and agglomerates made by the method which comprises agitating the fine particles in the presence of an organic polar liquid preferably nearly dry and having some ability to form hydrogen bonds (especially n-propanol) and then drying off most of the liquid whereby the fine particles spontaneously interlink (possibly by mechanical keying) in a way which allows the interlinks to be disrupted so as to release fine particles when the agglomerates are stirred into water by hand. Also a dry precursor mixture comprising the agglomerates containing conventional auxiliary additives for use in mixing with water to make aqueous compositions for use as filler pastes, casting materials or plaster slurries.