| 摘要 |
<p>Prepn. of stable sodium peroxycarbonate of high apparent specific weight and uniform particle size, comprises continuous crystallisation by the following method:- (a) 50-90% Aq H2O2 and purified Na2CO3 soln. are introduced continuously into a crystallisation zone; (b) the two are reacted maintaining the concn. of the sodium peroxycarbonate above the saturation level under 0.5-15 hrs; (c) water is evaporated at 1.5-15 mols/mol of sodium peroxycarbonate produced; (d) a crystal suspension is withdrawn, the crystals sepd. and dried to recover sodium peroxycarbonate of specific weight 0.9-1 g/cm3; (ee the sepd. mother liquor is treated to decompose H2O2; fresh sodium carbonate is added to form a 25-33% soln. at 27 degrees C or above and (f) the Na2CO3 soln. is purified to removve Fe and other transition metals, then the treated soln. is passed to stage (a). The prod. is used as a bleaching agent in detergent compsns. The process gives crystals of high specific weight, which are easily dried and are less friable and have less tendency to segregate in compsns.</p> |
