PROCESS FOR THE PRODUCTION OF A FILLER FOR PVC MOULDING MATERIALS, THE USE OF THE FILLER PRODUCED BY THIS PROCESS AND PVC MOULDING MATERIALS CONTAINING THE FILLER PRODUCED BY THIS PROCESS

摘要

The invention relates to a method for the manufacture of PVC molding compositions based on calcium sulfate anhydrite II, wherein is wetted calcium sulfate dihydrate with a dilute acid and dehydrating the mixture is subjected to a heat treatment at a temperature high. For this purpose, either a) the mixture is subjected to a heat treatment at temperatures of 50 to 190 ° C and the remaining acid is neutralized in the product obtained with an alkali carbonate and / or alkaline earth metal, while extracting the residual water or in training as well as the carbon dioxide formation, or b) the mixture is heated against the current with a hot gas at temperatures above 350 ° C, then cooled, is liberated, by sieving, all the particles having a diameter greater than 90 mu m, preferably 63 mu m, and is optionally comminuted.