| 摘要 |
A dry fire-extinguishing powder comprising KHCO3 and a hydrophobic agent is prepared by grinding the components and treating with CO2 under conditions suitable for converting into KHCO3, K2CO3 that has been formed by decomposition of KHCO3 and water formed on such conversion is removed. The treatment with CO2 may be under superatmospheric pressure, e.g. 1 to 3 atmospheres gauge, and the grinding may be carried out such that at least 50% by weight of the product is able to pass through a 0.042 mm. sieve. Hydrophobic agents specified are: stearates of calcium, zinc and magnesium, and may be present in an amount of 1%. Finely ground mica, shale or gypsum may be added in amount 5-15%, together with 1% of Ca3 (PO4)2 prior to the CO2 treatment. The KHCO3 may be prepared in the foam phase by reacting a 50% solution of K2CO3 with CO2.ALSO:A dry fire-extinguishing powder comprising KHCO3 and a hydrophobic agent is prepared by grinding the components and treating with CO2 under conditions suitable for converting into KHCO3, K2CO3 that has been formed by decomposition of KHCO3, and water formed on such conversion is removed. The treatment with CO2 may be under superatmospheric pressure, e.g. 1 to 3 atmospheres gauge, and the grinding may be carried out such that at least 50% by weight of the product is able to pass through a 0,042 mm. sieve. Hydrophobic agents specified are: stearates of calcium, zinc and magnesium, and may be present in an amount of 1%. Finely ground mica, shale or gypsum may be added in amount 5-15%, together with 1% of Ca3(PO4)2 prior to the CO2 treatment. The KHCO3 may be prepared in the foam phase by reacting a 50% solution of K2CO3 with CO2. |
