Gypsum-containing board and tile, and method for producing gypsum-containing board and tile

A method the producing a set gypsum-containing board or tile comprising:

• forming a composition comprising a mixture of a calcium sulfate material, water, from about 0.015 weight percent to about 1.5 weight percent, based on the weight of calcium sulfate material in the mixture, of chloride ions or salts thereof, and one or more enhancing materials selected from the group consisting of:
• condensed phosphoric acids, each of which comprises 2 or more phosphoric acid units;
• and salts or ions of condensed phosphates, each of which comprises 2 or more phosphate units, and
• maintaining the mixture under conditions sufficient for the calcium sulfate material to form or maintain an interlocking matrix of set gypsum material.