Re: Cullet
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Russ Strodtz <railfreightcars@...>
My vote is with Mr Thompson. That is why the cullet was sent back to
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the plant that the bottles were made at. One would think that they would almost always have batches of brown glass stewing since beer bottles were one of their biggest products. Another thing comes to mind. I'm sure most of us are familiar with the heavy, sort of waxy, cardboard cartons that refillable beer was/is sold in. That was what the new bottles were shipped in. I'm sure their thinking was that even though they had to be taken out to be filled those cartons had to be bought at some time in the process and their use would cut down on breakage. The purchasing and delivery of packaging materials may have been the reason that there were so many CP and CN cars to be found around the glass plants. Russ
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From: Anthony Thompson To: STMFC@... Sent: Tuesday, 30 October, 2007 01:07 Subject: Re: [STMFC] Cullet John C. La Rue, Jr. wrote: > I suspect that any coloring agents would have been removed when the > cullet was melted in the furnaces, much as carbon and trace additives > are removed when scrap iron and steel are melted...the additives unite > with the limestone to form slag, which is removed, thus leaving pure > iron. Different process, John. In fact, colored glass is QUITE hard to re-clarify. You can mix brown and green glass, but not put either one into clear glass. And blue glass is a serious contaminant for any other glass color. There are several reasons, but an important one is that glass melting is a very slow process, mostly due to the viscosity and resulting slow circulation and mixing of the glass--24-hour melts are common, whereas steelmaking can be accomplished in 90 minutes or less. (That's the reason that glass recycling really saves little energy; the process takes about as long, and about as much energy, whether you use raw materials or cullet. But you DO take all those bottle-size voids out of landfills.) Another difference from iron refining is that there is no slag equivalent in glassmaking. Anthony Thompson Dept. of Materials Science & Engineering University of California, Berkeley thompsonmarytony@...
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