| 摘要 |
PROBLEM TO BE SOLVED: To provide a sodium hypochlorite pentahydrate crystal having an abated content of sodium chlorate suspected of exerting harmful effects on health and a method for manufacturing the same.SOLUTION: The content of sodium chlorate within the provided sodium hypochlorite pentahydrate crystal is 200 ppm or below. Moreover, the method of the present invention for manufacturing a sodium hypochlorite pentahydrate crystal comprises: a first step of obtaining a mother liquor by reacting an aqueous sodium hydroxide solution with a chlorine gas; a second step of solid/liquid-separating sodium chloride from the mother liquor; a third step of adding a seed crystal to the mother liquor set at a specified cooling commencement temperature; a fourth step of depositing a sodium hypochlorite pentahydrate crystal by cooling the mother liquor at a cooling rate of 1 to 20°C/hour eventually at a specified cooling conclusion temperature; and a fifth step of solid/liquid-separating the sodium hypochlorite from the sodium hypochlorite pentahydrate crystal. |
