Abstract

The present invention relates to the use of sacrificial agents to counteract the deleterious impact of gypsum contaminants on the effectiveness of certain stucco additives, particularly, water reducing agents and foaming agents, in a stucco slurry used to make gypsum wallboard.

IPC Classes  ?

• C04B 41/65 - Coating or impregnating with inorganic materials
• C04B 41/62 - Coating or impregnating with organic materials
• C04B 41/61 - Coating or impregnating
• C04B 41/60 - After-treatment of mortars, concrete, artificial stone or ceramicsTreatment of natural stone of only artificial stone

Abstract

A gypsum wallboard and a method of making the wallboard using a modified beta-gypsum hemihydrate obtained by calcining gypsum in the presence of a calcination modifier, under conditions for forming a beta-gypsum hemihydrate, wherein the wallboard is prepared using a stucco slurry formed by mixing the modified beta-gypsum hemihydrate with water, pre-gelatinized starch and a stucco dispersant.

IPC Classes  ?

• C04B 28/14 - Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing calcium sulfate cements
• C04B 11/024 - Ingredients added before, or during, the calcining process, e.g. calcination modifiers
• C04B 38/10 - Porous mortars, concrete, artificial stone or ceramic warePreparation thereof by using foaming agents
• C04B 111/00 - Function, property or use of the mortars, concrete or artificial stone
• C04B 111/10 - Compositions characterised by the absence of a specified material