Process for the continuous dehydration and calcination of hydrated aluminum fluoride for the manufacture of high purity aluminum fluoride

摘要

The invention relates to a continuous, two-stage process for complete dehydration and subsequent calcination of aluminum fluoride hydrates. PPThe known processes used for this purpose are satisfactory for producing relatively small quantities of aluminum fluoride. In the production of larger quantities of aluminum fluoride however several problems arise with respect to trouble free control and supervision of the process and maintainance of the equipment.P PThe disadvantages which up to now have been mainly due to the process itself are removed by the combination of the following process steps:P P(a) Dehydrating the aluminum fluoride hydrate in a first step, to produce aluminum semi-hydrate AlF.sub.3.0.5H.sub.2 O by means of a generally known methodPP(b) heating the aluminum semi- hydrate in a second stage in an indirectly heated, horizontal rotary kiln to remove the remaining water of crystallization, and then calcining at ca. 500-600 C.