Commercially produced glass can be classified as soda-lime, lead, fused silica, borosilicate, or 96 percent silica with soda- lime glass representing three-quarters of the glass produced. Glass is manufactured from materials that are crushed, weighed, mixed and melted to produce flat glass, container glass, pressed glass and blown glass.
Typical applications producing dust include —
- Intake hoppers and pits, elevators, screw and belt conveyors, holding bins and silos, weigh stations, mixers, feeders, cullet crushers and screens.
Feed materials commonly are —
- Major Ingredients: Sand, Limestone, Soda Ash, and Cullet (broken glass)
- Minor Ingredients: Salt cake, aluminum oxide, barium oxide and oxides of iron, nickel, manganese and copper added to impart colour to glass.
Characteristscs of dust in the various processes are —
- Sand: course and free flowing.
- Limestone: usually slightly agglomerative with wide particle size distribution, filters and cleans down easily.
- Soda Ash: relatively fine with agglomerative characteristics, hygroscopic and should be kept dry.
- Cullet: large irregular shaped particles, very abrasive
FILTER CONSIDERATIONS FOR GLASS DUST
Polyester felt is the typical media choice for baghouse applications on glass production processes at ambient temperatures. Exotic media is often required at elevated temperatures, and selection has to consider the actual chemistry of the process. Protecting bags from direct abrasion is especially important when handling sand or cullet dust streams. Because glass dusts contain high percentages of silica, high levels of filtration efficiency must be a consideration in filter media selection, collector selection, and in collector sizing.
Cullet crushing is a challenging dust collection application requiring specific collector design. Intake materials are particularly abrasive, and dust loadings are often very high, so heavy gauge hoppers and airflow management are critical to collector success.
Sand, cullet, and limestone bin vents now benefiting from the advantages offered in both efficiency and size with the CP Series PowerCore collectors. The characteristics of soda ash still benefit from the performance of the DLMV in handling potential upset conditions associated with humidity and/or moisture.