The effects of some organic acids and salts on the setting of gypsum plaster III. citrates

Abstract A study has been made of the effects of citric acid, potassium citrate and calcium citrate on the setting of calcium sulphate hemihydrate plaster, in continuation of previous studies on this reaction.1,2 The citrates showed more complicated effects than the additives previously tested, and the following factors are taken into account in interpreting the experimental results: (i) formation of complexes, (ii) adsorption, (iii) metathesis and (iv) the accelerating effect of an alkali metal ion, if present.