Solid Waste Source Reduction and Recycling
Published in Charles R. Rhyner, Leander J. Schwartz, Robert B. Wenger, Mary G. Kohrell, Waste Management and Resource Recovery, 2017
Charles R. Rhyner, Leander J. Schwartz, Robert B. Wenger, Mary G. Kohrell
Silica sand, a very pure form of silicon dioxide, is the most common ingredient in glass manufacturing. Sodium oxide, commonly known as soda ash, is used as a fluxing agent to lower the high melting point of sand. Blending limestone, the third major glass ingredient, with the soda ash reduces water solubility. Silica sand, soda ash, and limestone are all available in abundant supplies. By adding alumina, boric oxides, coloring agents, or other minor ingredients, easily formed durable containers can be produced. In addition to these ingredients, the glass container industry has always used in-house cullet in its batches because cullet melts at lower temperatures than the virgin raw materials used to make glass. If significant quantities of cullet are used, its lower melting results in energy savings in the manufacturing process. As noted in Table 4.3, energy savings are likely to be in the range of 4% to 32%.