The process of the iron-containing alumina ball
The process according to claim 5 wherein said iron-containing alumina ball are prepared by the process which comprises tumbling iron shot with powdered high refractory alumina with sufficient water to provide a heavy alumina coating on said shot, and then heating said alumina coated iron shot to a temperature of about 2800 F. to 3400 F. for a time sufficient to result in said iron-containing alumina ball.
Pyrolyzing said preheated crushed oil shale with hot iron-containing raschig ring under conditions of temperature, pressure, and for a time sufficient to substantially convert said oil shale to produce a pyrolyzed admixture of shale oil, spent hot shale, and spent carbonaceous iron-containing alumina ball, wherein said iron-containing alumina ball contain about 10 to 90 weight percent iron in a sufficient state as to permit magnetic separation from said spent shale.
As will have been noted, certain of the processes tend to result in a limited amount of iron substantially on the surface of the ceramic ball. It is to be anticipated that such surface iron may tend to promote formation of carbon at the surface of the ball at the reducing conditions involved in retorting of the shale oil, which may tend to decrease somewhat the life of the balls. Of course, such carbon effectively will be substantially burned off at the time of air treatment of the ball. Processes of ball-making by which most of the iron is internal tend to minimize this effect.