Crystallographical and Morphology Control of Goethite Particles

Abstract

The crystallographical and morphological properties of goethite particles in the course of oxidation in the strong alkaline solution was studied from X-ray diffraction analysis under the systematically controlled synthesizing conditions. The crystallite size ratio, D₀₁₀D₁₁₀, was changed by excess alkali content and oxidation conditions. The particle morphology of goethite depends on the relative growth rates of each faces of goethite crystals. From the SEM observation, the vertical and horizontal axes of goethite are proposed to be (110) and the lateral growth is assumed to be occurred along (110) easily because of the topotaxy between Fe(OH)₂ and goethite. It is concluded that the crystallite size ratio depends on the development of (110) face during crystal growth, which in turn, is related to the ferrous complex (FeOH⁺) content.