| 摘要 |
<p>1,264,672. Alumina monohydrate; basic aluminium nitrate. ALLIED CHEMICAL CORP. 23 April, 1969 [21 May, 1968], No. 20856/69. Heading C1A. Al 2 O 3 .H 2 O is prepared by heating an aqueous solution of basic aluminium nitrate of formula Al 2 O 3 .pN 2 O 5 , where p is 0À75 to 2À25, at a concentration of less than 25% NO 3 by weight, at temperatures of at least 180‹ C., preferably 190-210‹ C. under autogenous pressure. Suitable basic nitrates comprise Al(OH) 2 NO 3 and some Al(OH)(NO 3 ) 2 . Seed crystals of alumina monohydrate may be added to give Al 2 O 3 H 2 O crystals of particle size of 15 microns or higher. The basic aluminium nitrates may be prepared by partially denitrifying Al(NO 3 ) 3 .9H 2 O by heating at above the decomposition temperature but less than 230‹ C. and at a pressure in excess of 175 kg./cm.<SP>2</SP> while venting to release HNO 3 (as described in Specification 1,083,537).</p> |
