| 摘要 |
1,142,304. Sodium perborate trihydrate. SOC. D'ELECTRO-CHIMIE, D'ELECTROMETALLURGIE ET DES ACIERIES ELECTRIQUES D'UGINE. 15 Feb., 1966 [17 Feb., 1965], No. 6581/66. Heading C1A. Sodium perborate trihydrate is made continuously by introducing into a crystallizer an aq. soln. containing 27-75% H 2 O 2 and an aq. soln. containing 200-500 g./l. NaBO 2 in stoichiometric proportions or with a slight excess of NaBO 2 . Into the lower part of the crystallizer is introduced a fluid suspension of hollow seed crystals of sodium perborate having an apparent density of 0À15-0À3 g./c.c. and an average diameter of 120-400Á. The weight of seed crystals: weight of perborate produced may be maintained between 2/3: 1 and 1/6: 1. The seed crystals may be introduced into the crystallizer below the NaBO 2 and H 2 O 2 inlets. The seed crystals flowing out of the crystallizer may be recycled and introduced into the crystallizer at 15 min. time intervals. The seed crystals can be made by simultaneously and rapidly introducing into a vessel an aq. soln. containing 100-300 g./l. NaBO 2 and a soln. containing 15-40% wt. H 2 O 2 and cooling, e.g. to below 5‹ C., the solution to crystallize sodium perborate trihydrate seed crystals. |
