Presentation1_Formation and Coloring Mechanism of Typical Aluminosilicate Clay Minerals for CoAl2O4 Hybrid Pigment Preparation.pdf

Different kinds of aluminosilicate minerals were employed to fabricate CoAl₂O₄ hybrid pigment for studying its formation and coloring mechanism. It revealed that the color of the obtained hybrid pigments was determined by the content of Al₂O₃ and lightness of clay minerals. The higher the Al₂O₃ content and the lightness of clay minerals, the better the color parameters of hybrid pigments. During the preparation of hybrid pigments, CoAl₂O₄ nanoparticles were confined to be loaded on the surface of the aluminosilicate minerals, which effectively prevented from the aggregation and the size increase of CoAl₂O₄ nanoparticles. What's more, aluminosilicate mineral might be an ideal natural aluminum source to compensate the aluminum loss due to the dissolution of Al(OH)₃ at alkaline medium during precursor preparation, keeping an optimum molar ratio of Co²⁺/Al³⁺ for formation of spinel CoAl₂O₄ pigments in the process of high-temperature crystallization.