Materials Science

Acceleration of the setting of hemihydrate plaster with calcium sulfate dihydrate

Summary: The well-known procedure of accelerating the setting of hemihydrate plaster with calcium sulfate dihydrate was systematically analysed in its entirety during a research project [1] and further data were determined in certain specific areas. These findings were used as the basis for providing important guidelines for the production of a highly effective accelerator for industrial application, specific information about increasing its storage stability and practical recommendations for improving its workability.

1 Introduction
Calcium sulfate binders are required to have widely varying properties to meet technical and economic requirements. In particular, it has to be possible to vary the workability time and the time of the onset of stiffening of the binders over a period ranging from a few minutes to several hours. To cope with these requirements it is necessary to use additives to regulate the setting.
Acceleration of the setting is of crucial importance in the production of gypsum wallboard. Modern plants for producing gypsum wallboard can reach manufacturing speeds of up to 180 m per minute. The...

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