Dustiness and composition of various kieselgur (diatomaceous earth)

The dustiness of different kieselgur as well as of filter surrogate contain ing no quartz or cristobalite have been investigated under laboratory condi tions using two measuring equipments. Samples of diatomaceous earths contai ning quartz and/or cristobalite showed an almost uniform dustiness and a lo w degree of dust generated. The surrogates possessed a higher degree of dus tiness. The concentrations of quartz and cristobalite in the original sampl es and in the respirable dust fraction hove been determined. Almost all of the original samples of kieselgur contain less than 5 % (w/w) of quartz alo ng with cristobalite in a range of < 2 % to 46 %. In their respirable dust fraction, quartz amounts to < 1 % and cristobalite to a range of < 2 % to 7 1 %.