Magic Powder Called Portland Cement

Describes the cement hydration process and the production of Portland cement from raw materials to the finished product. Includes scenes from various cement plants which show the use of new technology to conserve fuel and control pollution and describes the work of the Portland Cement Association. Portland cement combines calcium from limestone, silica from clay, and aluminum and iron from shale and slate. Film shows massive rotary ovens, silos, and ore-heating towers.