Why is chrome flour with 38-41% Cr2O3 also called glass powder in China?
The reason why chrome flour with 38%-41% Cr2O3 is called “glass powder” is mainly related to its specific application and composition characteristics in the glass industry. The specific reasons are as follows:
Core use relevance
Chrome flour with this content range is mainly used as glass colorant. Through the chemical reaction of chromium (Cr₂O₃) and glass matrix at high temperature, it gives glass a specific color such as green or brown. For example, container glass such as beer bottles and wine bottles needs to be added with such chrome flour to achieve UV resistance. This use directly facing the glass industry makes it called “glass powder” in the industry.
Chemical composition and performance adaptability
Chromium content matching: 38%-41% Cr₂O₃ content can not only meet the glass coloring needs, but also avoid the high cost or process adaptation problems that may be caused by high chromium content (such as ≥46%).
Particle size requirements: Its conventional mesh (such as 200 mesh, 325 mesh, 400 mesh) is highly consistent with the melting and dispersion process in glass production, ensuring color uniformity and stability.
High temperature resistance: Chrome flour has a stable volume during glass melting and does not react with molten metal, which can prevent sand from sticking or penetrating into castings, meeting the requirements of glass manufacturing for material stability
Industry naming conventions In the glass industry, materials are often named according to the function of the raw materials (such as “glass beads” and “glass fibers”), and this type of chrome flour is specifically used for glass coloring and has a powdery appearance, so it is referred to as “glass powder” to distinguish it from other chromite products for metallurgical or casting purposes
