Synthetic wollastonite - by calcining crude calciferous and siliceous material in rotary furnace

摘要

Mixt. of (1) crude calciferous material at least 50% of which is quicklime, and (2) crude silicious material being crushed quartzitic sand in a stoichiometric excess of 5-10% over (1) is calcined at above 1400 degrees C. At least 90% of the particles in the mixture are 0.09 mm in size, and the impurities in the mixture or in the final product consist of: less than 1% in total of oxides of Al and Fe, and less than 0.1% alkalis; the mixt. being introduced into the furnace without having been formed into briquettes or granules and without the addition of binders. Advantages are regular functioning of the furnace without formation of scale; precompaction unnecessary; dicalcium silicate undetectable.