Glassing Tubing for Glass Frit and Powder

Special use case glass powder can be generated by Corning and one special use case in particular is glass powder for glass microspheres or glass beads as they are often referred to. To generate a glass microsphere, glass powder is sized to a specific distribution. The glass powder can be borosilicate or any Corning glass but precise microsphere size is predicated on the starting glass powder size range. This highly specialized glass powder raw material must be produced in a size range and depending on the target size distribution small particles called fines are discarded while large sieve sizes are cycled back to the mill for processing. The process of sieving to a specific distribution with a narrow range can be costly and time consuming but required to generate a precise microsphere from a precise controlled powder size distribution. Additional care in this process is needed to reduce iron contamination and many of the components of the mill and sieve are nylon, ceramic or nonmetallic to reduce the amount of iron contamination of the powder.

Cleaned, dried and sized glass flakes or shards are often referred to as Glass Frit. Corning supplies several grades and sizes of crushed glass frit for various applications in both borosilicate and aluminosilicate glasses. The material is milled and screened to size with low free iron contamination from the crushing event. The glass is packaged in super sacks and palletized ready for sale. Glass Frit is typically included in the recipes of many items such as glass remelt, glass powder, insulation or ceramic paints. Glass powder is milled from a glass frit and the starting glass frit feed stock is sized appropriately to maximize the powder size generated from the powder milling operation.    

Corning glass powder is commonly supplied in Corning C33, 7740 glass including 325 and 200 mesh but any custom size is readily available. Glass powder is generated by milling glass frit in a special mill, normally a ball mill and often with ceramic media. The glass is sieved and separated to size to generate a powder below the target dimension. Our process carefully monitors the free iron ppm the glass generates during the milling process and is reduced by the use of magnets and testing to ensure each batch exceeds the customer iron-free specifications. A certification for the material accompanies each batch confirming the size distribution, chemistry and free iron.