Silicates of green colour - highly dispersed pigments

The technique is presented for obtaining green pigments in the reaction of precipitation from sodium metasilicate solution and from chromium (III) salts. Sulphates and chlorides of chromium (III) as well as chromium sulphates from the tanning industry refuses were applied. The studies were directed to obtain pigments of the following composition: xCr2O3 ySiO2 zH2O. Basic conditions of precipitation process, filtration and drying of silicate pigments were established. Moreover, principal physicochemical parameters of the precipitated pigments were evaluated as well as the size and morphology of pigment particles being estimated by electron microscopy. The performed physicochemical studies aimed also at determining suitability of the pigments as fillers and carriers in oil paints.