The color of kaolin
The color of kaolin is mainly related to its metal oxides or organic matter. Generally, Fe2O3 contains rose red and brown yellow; Fe2+ is light blue and pale green; MnO2 is light brown; and organic matter is light yellow, gray, green, black and so on. The presence of these impurities reduces the natural whiteness of kaolin. Iron and titanium minerals also affect the calcination whiteness, resulting in a stain or scar on the porcelain.