Abstract: Alumina values are extracted from clay by the steps of pelletizing into spherical particles, calcining the pellets in a fluidized bed reactor, extracting the clay in about 30-40% nitric acid, purifying the basic aluminum nitrate produced, crystallizing aluminum nitrate nonahydrate, decomposing the nonahydrate in at least three steps, calcining the produced alumina and reconstituting the NO.sub.x gases to nitric acid.

Abstract: There is described a method for the decomposition of aluminum nitrate crystals to alumina comprising the steps of:(a) melting the aluminum nitrate crystals;(b) evaporating from the melted crystals in a once through evaporator at the boiling temperature of the mixture and for a time sufficient to remove water and associated nitric acid and to provide a fluid having an alumina concentration of at least about 18% by weight;(c) decomposing the product of step (b) at a temperature of between about 150.degree. and about 200.degree. C. and recovering the heat of condensation of the resultant vapors;(d) further decomposing the product of step (c) in a fluidized bed decomposer at a temperature of between about 300.degree. and about 400.degree. C. to reduce the residual nitrate concentration in the product to between about 5 and about 10 weight percent;(e) decomposing the product of step (d) in a fluidized bed decomposer at a temperature of between about 500.degree. and about 800.degree. C.

Abstract: A method and apparatus for cleaning a paper making felt continuously during the paper making process, and wherein the moving felt is passed through a cleaning bath, and ultrasonic vibrations are applied substantially uniformly across the entire width of the felt while the felt is immersed in the bath, to thereby achieve uniform cleaning of the felt and thus uniformity in the paper produced on the machine. A circulation system for the bath is provided for continuously separating the dislodged fibrous residue therefrom, while retaining the chemicals and heat, and the apparatus includes provision for readily replacing the felt.

Abstract: An apparatus for cleaning an endless paper making felt continuously during the paper making process, and wherein the moving felt is passed through a cleaning bath, and ultrasonic vibrations are applied substantially uniformly across the entire width of the felt while the felt is immersed in the bath, to thereby achieve uniform cleaning of the felt and thus uniformity in the paper produced on the machine. The apparatus comprises an open, rectangular tank having a removable end wall, and a guide roll and ultrasonic transducers movably mounted in the tank, whereby the endless felt may be readily removed and/or replaced by removing the end wall, and lifting the guide roll and transducers, so that the felt may be slipped into the tank beneath the guide roll and transducers.