Finally, we fulfill the purpose of this little sub-project, which is to compare the energy needed to make bricks with and without recycled container glass as the grog.
Please recall that in contrast to other studies of glass as a raw material in brick manufacturing, we are using very coarse glass (12 mesh and finer), just as it is already being processed for the fiberglass industry.
The 50 percent glass brick meeting ASTM C1272-05a, “Standard Specification for Heavy Vehicular Paving Brick,” was fired as follows:
90 minutes to 1850F
hold 20 minutes at 1850F
The minimum firing profile that produced a specification-meeting brick using 50 percent grog was
90 minutes to 2100F
30 minutes at 2100F
During brick production we have been monitoring energy use during each kiln firing. The chart below shows the energy consumption in btu’s per pound for the glass and grog bricks:
The blue line is the 50 percent glass bricks. The purple line is the grog bricks. The scale on the left is btu’s per pound of brick fired.
The kiln was then fired empty to the same two profiles. This will show us how much energy the bricks themselves used.
Here’s a graph of the energy consumed by the empty kiln, normalized for btu’s per pound of bricks when the kiln is full of bricks:
The purple line is for the profile with the grog bricks. The blue line represents the profile for the glass bricks. The scale is btu’s per pound of brick (when the kiln is full).
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