A set of empirical equations is presented for modelling the precipitation of aluminium, silicon and phosphorous in green liquor plants as a function of initial concentrations of these elements plus magnesium, calcium and alkali in the dissolver. As process parameters, the model includes residence time and temperature. Concentrations, temperature and residence time have been varied according to a factor design plan. Main findings are that in laboratory experiments it was possible to remove aluminium, silicon and phosphorous down to concentrations below their solubility in white liquor thus avoiding accumulation of these elements in the lime cycle. In addition, the experimental work showed that the initial concentrations of aluminium, silicon and phosphorous in raw green liquor have a strong increasing impact on their concentrations in filtered green liquor.