| 摘要 |
There is described a process for preparing large crystals of basic aluminum nitrate (BAN) from a nitric acid feed solution containing Al2O3 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 DEG and about 450 DEG 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 DEG F. to about 340 DEG 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 (Al2O3.6HNO3.15H2O or Al(NO3)3.9H2O), and (2) The desired crystal product BAN or Wiseite (a) BAN (Al2O3.2HNO3.5H2O or Al(OH)2NO3.2.OH2O). or (b) Wiseite (Al2O3.2HNO3.4H2O or Al(OH)2NO3.1.5H2O) to precipitate large crystals of BAN; and (4) separating the large crystals. |
