Preparation method for a-type hemihydrate gypsum

(22) 02.11.2022

(43) 29.06.2023

(57) A preparation method for an a-type he-mihydrate gypsum, comprising the following steps: (1) enabling a desulfurized = gypsum suspension and propionic acid to react at 120-140 C for 3-5 hours; (2) carrying out solid-liquid separation, and carrying out vacuum drying at 40-80° C to obtain an a-type high-strength hemihydrate gypsum. In the present preparation method for the ci-type high-strength hemihydrate gypsum, propionic acid is used as a crystal transfer agent, only three carboxyl groups are contained, the distance between every two adjacent carboxyls is two C atoms, and no complex void groups are contained. Thus, the a-type highstrength gypsum tends to develop in the radial direction, a short-column-shaped a-type high-strength gypsum crystal is obtained, the strength‚1IC of the a-type high-strength gypsum is improved, and resource utilization of the desulfurized gypsum is facilitated.

(71) Henan Polytechnic University, Henan 454000 (CN)