DEVELOPMENT OF A FLUIDIZED BED CALCINATION PROCESS FOR ALUMINUM NITRATE WASTES IN A TWO-FOOT-SQUARE PILOT PLANT CALCINER PART I. EQUIPMENT DEVELOPMENT AND INITIAL PROCESS STUDIES

摘要

A two-foot-square fluidized bed calciner was designed and operated to further the development of a process to convert aqueous, highly radioactive wastes into granular solids. The calciner exceeded somewhat its designed feed capacity of calcining, at a bed temperature of 400° C, 100 liters per hour of aluminum nitrate solution simulating wastes from the reprocessing of spent aluminum-uranium alloy reactor fuel.nHeat was supplied to the calciner by circulating NaK with an elec-tromagnetic pump, at temperatures up to 1400° F, through a tubular heat exchanger placed directly in the fluidized bed of solids.nThe results of ten extended runs made in the calciner are presented and discussed. Equipment development progressed to the point where a continuous, trouble-free, operating period of 43 days was attained. Several properties of the alumina product were routinely measured, and some of the effects of the calciner operating variables on these proper-ties were determined. The production of both amorphous and alpha crystalline material was found to be possible;the crystalline nature of the product had a profound effect on product properties and off-gas loading.