| 摘要 |
PURPOSE:To prepare novel anhydrous sodium carbonate having small apparent specific gravity, high particle hardness, and high rate of dissolution, by mixing crude sodium bicarbonate with anhydrous sodium carbonate and water under specific condition, and calcining the mixture to obtain particles having specific diameter. CONSTITUTION:(A) Crude sodium bicarbonate obtained by the ammonia soda process or ammonium chloride soda process is mixed with (B) anhydrous sodium carbonate obtained by calcining the above crude bicarbonate keeping the outlet temperature of the calcination to 100-300 deg.C, and (C) water, at a weight ratios of 1:(0.2-1.5):(0.1-0.8) and 40-105 deg.C. The mixture is calcined at 100-300 deg.C to obtain particles having average particle diameter of 200-600mu. The objective novel anhydrous sodium carbonate obtained by this process has an apparent specific gravity of 0.4-0.7, the pulverization ratio of the particle hardness of <=10%, and the rate of dissolution in water of <=40 seconds, and contains rod- like crystals aggregated on the surface of the particle.
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