Bulletin 236 Plastic Magnesia

Much detailed information on the production of plastic magnesia from magnesite mined near Chewelah, Wash., was accumulated during a cooperative investigation conducted by the Bureau of Mines and the Northwest Magnesite Co. at the laboratories of the University of California in 1919-1921. This bulletin gives mainly the results of the work done with Chewelah magnesite, supplemented by data on similar work with other magnesites, particularly those of California, in the endeavor to produce a plastic magnesia that would be satisfactory for making the so-called " Sorel" cement composition flooring, stucco, and plasters. As standardized methods £or testing such compositions did not exist, it was necessary to examine carefully the various methods in use and choose those that seemed appropriate. In consequence, this report contains many tests made by the methods selected and can be used £or reference by those who wish to adopt standard methods of testing.