Abstract: There is described a process for the reconstitution of NO.sub.X gases produced by the thermal decomposition of metal nitrates to nitric acid comprising the steps of:1. contacting the NO.sub.X gases in counter-current relationship in one or more packed columns with cooled 50 to 60 percent nitric acid to remove as nitric acid a major portion of the originally introduced NO.sub.X values and provide an acid solution leaving the column having a temperature below about 180.degree. F. to remove as nitric acid a major portion of the originally introduced NO.sub.X values;2. compressing the residual gases from step 1 to from about 2 to about 6 atmospheres absolute;3. contacting the compressed gases from step 2 with from about 50 to about 60 percent nitric acid in a packed absorption column in counter-current relationship to remove substantially all of the remaining NO.sub.X values from the gas stream as HNO.sub.3 ; and4. recovering 50-60% nitric acid as it accumulates.

Abstract: There is described a process for preparing large crystals of basic aluminum nitrate (BAN) from a nitric acid feed solution containing Al.sub.2 O.sub.3 values comprising the steps of:(1) evaporating water and nitric acid from the solution in a single step evaporation performed at a temperature of between about 270.degree. and about 450.degree. F. and at a pressure of between about atmospheric and about 60 psig to produce an evaporated liquor comprising at least about 16% alumina by weight;(2) holding the evaporated liquor in a quiescent state for a period of between about 20 minutes and about two hours within the temperature range of about 270.degree. F. to about 340.degree. F.;(3) injecting water into the product of step 2, the water being added in an amount sufficient to adjust the composition of the conditioned liquor to a composition expressible as the sum of two components(1) ANN (Al.sub.2 O.sub.3.6HNO.sub.3.15H.sub.2 O or Al(NO.sub.3).sub.3.9H.sub.

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.