Micronized pyrolusite used thereof as a natural oxydant in the ceramic and chemical industry and process for the preparation thereof

摘要

The invention relates to a micronised pyrolusite enriched in particles with a particle size of less than 2.5 micrometres and having a high specific surface. The pyrolusite according to the invention is capable of being obtained by the following treatment of extracted crude pyrolusite ore: a) production of an ore with a particle size of less than 15 mm, in particular by crushing and screening and simultaneous removal of a sterile part, b) controlled and selective grinding of the ore obtained in stage a) so as to obtain a particle size of less than 500 micrometres and simultaneous removal of a sterile part, c) drying, d) selection, in particular pneumatic, of the particle size range so as to obtain the micronised pyrolusite. Use of the said pyrolusite as powerful natural oxidant (oxidising agent) in the ceramics industry and in the chemical industries where it can also act as catalyst and flame sensitiser promoting ignition of a combustive (oxygen-carrier).