Gypsum set accelerator

A method for manufacturing a gypsum-containing product, the method comprising:

• i) mixing a dry mixture comprising calcium sulfate dihydrate and one or more of the following:
• a polycarboxylic ether (PCE) and/or SMP, wherein the polycarboxylate ether is a co-polymer composed of oxyalkylene-alkyl ether, maleic acid and acrylic acid repeating units, and having a molecular weight in the range from 20,000 to 80,000 Daltons;
• wherein calcium sulfate dihydrate is mixed with the PCE in a weight ratio in the range from 0.1 to 5 parts by weight of the PCE and/or SMP per 100 parts by weight of calcium sulfate dihydrate;
• ii) co-grinding the dry mixture in a ball mill and producing a freshly ground gypsum set accelerator;
• iii) mixing at least calcined gypsum, water and the gypsum set accelerator obtained in step ii) into a gypsum slurry with a water/stucco ratio in the range from about 0.4 to about 1.5, wherein the gypsum set accelerator is mixed into the gypsum slurry either as a freshly ground gypsum set accelerator or after the gypsum set accelerator was aged, wherein the aged gypsum set accelerator retains set-accelerating efficiency when stored under humid conditions with humidity of 70% or higher, and wherein the gypsum set accelerator is added to the gypsum slurry in an amount in the range from about 0.1 wt % to about 5 wt % calculated based on the weight of calcined gypsum;
• and
• iv) forming a gypsum product from the gypsum slurry.