Raw material substitution in glass

["Frederick M. DeNorscia (412) 442-4343" <DENORSCIA.FREDERICK@a1.pader.gov>]

I got a call from a leaded-crystal glass manufacturer who would like to 
substitute potassium silicate for potash in their glass mix.  They theorize that 
by using the potassium silicate they could operate their oxy-gas furnace at a 
much lower temperature (thus saving energy and increasing the life of the 
furnace and refractories) because they would no longer have to burn off the 
carbonate in the potash.  Apparantly, if the carbonbate is not burned off at 
high temperatures the gas from the carbonate forms bubbles in the glass.  They 
tell me the potassium silicate is in a glassy state to begin with and will melt 
at a lower temperature also.

They asked if anyone has done this before and what effect this substitution has 
had on the quality and chemistry of the glass and what effect, if any, on air 
emissions.

Any information out there?

Thanks.

Fred DeNorscia
Office of Pollution Prevention and Compliance Assistance
PA Department of Environmental Protection
Pittsburgh, PA 15222-4745

412-442-4343  fax 412-442-4194