Some interesting knowledge points of ultramarine.
1.Ultramarine is a blue inorganic pigment that occupies a place among blue pigments with its unique red light. Ultramarine products are extremely versatile. In terms of coloring, it is used for blue paint, coating, rubber, ink, oil cloth, painting and blue paint on building exterior walls, and in whitening, it is used for papermaking, soap washing powder, starch, white products and civil wall painting.
2.Molecular Formula and Crystal Structure:
3.Typical color and chromogenic groups.
The sulfur ion (S3-) chromophore in the chemical structure of ultramarine pigments is the main reason for their blue color. It is difficult to imagine that sulfur, which normally appears yellow, could also act as a blue chromophore, but sulfur is certainly the case in a special valence state. In addition, by controlling the valence of sulfur in ultramarines, it is also possible to achieve the characteristic ultramarine purple and ultramarine pink.
4.Typical color and chromogenic groups.
The sulfur ion (S3-) chromophore in the chemical structure of ultramarine pigments is the main reason for their blue color. It is difficult to imagine that sulfur, which normally appears yellow, could also act as a blue chromophore, but sulfur is certainly the case in a special valence state. In addition, by controlling the valence of sulfur in ultramarines, it is also possible to achieve the characteristic ultramarine purple and ultramarine pink.
General production methods and process flow diagrams of ultramarines.
The production process takes place in a closed kiln where the air is exhausted to prevent the oxidation of the sulphur before it reaches the reaction temperature, and then the sulphur, clay and sodium carbonate are heated to about 800 °C. After maintaining the maximum temperature for a certain period of time, the initial chromophore is formed, and the mixture is then cooled, allowing air to slowly enter the kiln to complete the oxidation process. This high-temperature process takes more than two weeks to complete.