Monobasic potassium phosphate → Magnesium Phosphate

Participants

Reaction Steps

A fire resistant board with an estimated B—fire rating was made as follows. Dry ingredients including 435 grams magnesium oxide (Martin Marietta HR 98), 425 grams monopotassium phosphate (300 mesh), 250 grams wollastonite, plus 250 grams class fly ash produced a magnesium phosphate cementitious material. This was mixed with wet ingredients: 15 grams super plasticizer [Rheobuild 10000], 500 grams dry mPCM (Ciba Chemicals [now BASF/Ciba] DPNT-0176) and 820 grams of water. The dry ingredients were mixed thoroughly with the wet and placed in a 26 cm×31 cm×1.27 cm mold. A layer of 2.5 oz. nonwoven veil fiberglass fabric was placed on both sides. The board hardened and was de-molded in 8 hours. A Perkin Elmer Pyrus DSC1 Differential Scanning Calorimeter was used to test board enthalpy. The tested board enthalpy level was 29.7 J/g (427 KJ/m2), with a density of 1.15 g/cm^3. A propane torch was positioned 7 cm from the board face. The torch flame was directed at the center of the board and held in place for 10 seconds, and the flame extinguished when the torch was removed. The torch was applied a second time for 30 seconds when the torch was removed the flame again extinguished.

Provenance & Evidence