| 摘要 |
<p>. The present invention provides in a process for producing a compact coarse sodium percarbonate by reacting hydrogen percarbonate with sodium carbonate at 10 to 20.degree.C, starting with a solution which contains sodium carbonate and is saturated with sodium percarbonate, in the presence of 100 to 200 g of sodium chloride per litre of solution, stabilizers of active oxygen, and sodium hexameta-phosphate, the improvement in which is said solution, which contains 0.1 to 1.9 g of sodium hexameta-phosphate per litre of solution, the ratio of soda to sodium hexameta-phosphate is adjusted to a value from 65:1 to 500:1, and the soda solution or suspension thus produced is mixed with an amount of hydrogen peroxide which is practically equivalent to the amount of sodium carbonate dissolved or suspended or both, in the starting solution while maintaining approximately a constant same temperature during the entire precipitation, and during and after the addition of hydrogen peroxide up to 60 minutes after this addition the resulting supersaturation with dissolved sodium percarbonate is reduced by precipitating the sodium percarbonate, the salt obtained is separated and dried.</p> |
