Two-stage calcination process and plant therefor

(22) 11.08.2017

(43) 22.02.2018

(57) Process and plant for the calcination of gypsum in a two-stage process. Provided are a first stage (3) comprising a flash calcination and a second stage for final calcination in a reaction vessel (6). The gypsum is passed from the first stage to the second stage via a transfer conduit (4). According to the invention, the reaction vessel (6) of the second stage is indirectly heated (65), and water vapor is also recirculated in the second stage without supplying external vapor and/or water. The expelled water of crystallization from the second stage provides an autonomous supply of water vapor which, via a circulation system (7), may be fully utilized for supplying the second stage with the required water vapor. Thus, a high water vapor proportion may be maintained in the second calcination stage with no need for a separate vapor generation. Accordingly, little, if any, anhydrite is formed. The invention accordingly combines low (…).

(71) Claudius Peters Projects GmbH, Schanzenstraße 40, 21601 Buxtehude (DE)