Characterization, surface modification, and evaluation of Egyptian dolomite ore as an extender pigment for paint

Dolomite is of immense importance for industrial applications. It is occuring in many locations in Egypt. Complete investigation and identification of the ore has been performed via chemical analysis and spectro‐photometric measurements using X‐ray fluroscence, X‐ray diffraction and electron microscope. The X‐ray diffraction pattern indicated that Egyptian dolomite is a crystalline material and electron microscope analysis showed that it has a lameller shape. Egyptian dolomite sample was evaluated as an extender pigment according to standard international specifications and proved to be excellent one for coating applications. Surface modification of dolomite ore particles has been carried out using stearic acid in cyclohexane. The modification concerned with the determination of adsorption isotherm, sediment volume, sedimentation rate, and dispersion properties to determine monolayer surface coverage of the ore particles. The unmodified and modified dolomite samples have been incorporated in anticorrosive primer formulations. The painted films were tested and examined in the laboratory accelerated corrosion test. Promising results were achieved and the films showed high performance as efficient extender pigment for coating applications that can replace satisfactorily its similar imported pigments.