Silica, crystalline: quartz dust, cristobalite dust and tridymite dust (respirable fraction) [MAK Value Documentation, 2000]

Abstract

Published in the series Occupational Toxicants , Vol. 14 (2000) The article contains sections titled: Characterization of the substance Chemical and physical properties Occurrence Uses Exposure Exposure situation Sampling and analysis Exposure determination in epidemiological studies Toxic Effects and Mode of Action Toxicokinetics and Metabolism Effects in Man Genotoxicity Carcinogenic effects Non‐malignant effects Animal Experiments and in vitro Studies Genotoxicity Carcinogenicity Manifesto (MAK value/classification)

A study of radicals in industrial raw cristobalite powders

“…Industrial cristobalite can be produced starting from silica sands, through a process including a silica gel formation step. According to MAK (2012) and Nurbaiti and Pratapa (2018), in fact, cristobalite can be produced by dissolution of silica precursor, followed by the formation of a silica gel by desiccation, consisting of amorphous silica powders. Then, the final cristobalite powders are obtained by calcination (at T > 950 °C) for several hours of the dried silica gel (the duration of the process can vary).…”

“…Apart from quartz, cristobalite is the second most abundant polymorph on the Earth's crust, and the only polymorph, still but quartz, object of a relevant diffusion in the industrial production (MAK 2012). The main industrial applications of cristobalite conventionally span from abrasives to pigments, to metal casting, to the production of chemicals.…”