Al 3anany Science Cement.flv

Wait, wait, wait - from 3:00 - "the powder goes into a preheater. The temperature of the powder is eighty degrees Celsius upon entering. Within forty seconds, it gets more than ten times hotter."

That's problematic to this old chemistry teacher. Does that mean it's up to 800 C (80 C x 10)? or 3530 K (353 K x 10)? If I've learned nothing else from the gas laws chapter, it's that if we're talking about doubling temperature, we'd better be talking about absolute temperature.

In spite of the atrocious largely gibberish title, this is a How It's Made video about cement. The video covers initial limestone blasting (open pit mining, I guess), rock crushing, mixing to reach the right proportion of calcium carbonate, bonding the minerals together  and degassing (carbon dioxide release, anybody?) them via heat, and final grinding.

And then...and then...and then...

Sorry, the hypnotic motion of the grinding balls got me there for a second.

Where was I?