|Monthly Tech-Tip |
Description: 2CaO.3B2O3.5H2O, Argentina Colemanite
This is mined in North Argentina, in the Andes Mountains, at about 4500 meters altitude. It is sold mainly for use in fiberglass, ceramics, glass, and as fertilizers. Production in 2002 was about 50,000 tons per year. Material can be ground to 200 mesh. Material is normally sold in bulk bag but the company has facilities to pack in 25 and 50 kg bags also.
As2O3: 300-600 ppm
Size Granulated or Crushed to 20 mesh
A natural source of boron that melts at a very low temperature.
Materials that source Na2O, K2O, Li2O, CaO, MgO and other fluxes but are not feldspars or frits. Remember that materials can be flux sources but also perform many other roles. For example, talc is a flux in high temperature glazes, but a matting agent in low temperatures ones. It can also be a flux, a filler and an expansion increaser in bodies.
|By Tony Hansen|
Follow me on