磷石膏制备高纯碳酸钙的试验研究

Experimental Study on Preparation of High-purity CaCO3 from Phosphogypsum

  • 摘要: 基于磷石膏的资源化利用,采用化学浸出—碳化的方法制备了一种球霰石型轻质碳酸钙。以工业固废磷石膏为原料,进行了磷石膏浸出和碳化的单因素试验。试验结果表明,最优的磷石膏浸取工艺条件为:乙酸钠溶液浓度4 mol/L,液固比25∶1 mL/g,盐浸温度50 ℃,盐浸时间30 min;最优碳化工艺条件为:氨水添加量15 mL,CO2气体流速80 mL/min,碳化温度30 ℃,碳化时间60 min。产物轻质碳酸钙经表征后,得出产物为球霰石型碳酸钙。乙酸钠助剂经过8次循环后仍可制备出轻质碳酸钙,助剂两次循环后,轻质碳酸钙产率为57.8%。该研究为磷石膏的综合利用和轻质碳酸钙的生产提供了一种新的方法。

     

    Abstract: Based on the resource utilization of phosphogypsum, a kind of spherical calcium carbonate was prepared by chemical leaching-carbonization method. The single factor experiment of leaching and carbonization of phosphogypsum was carried out. The experimental results showed that the optimal extraction conditions of phosphogypsum were as follows: sodium acetate concentration of 4 mol/L, liquid-to-solid ratio of 25∶1 mL/g, salt leaching temperature of 50 ℃, salt leaching time of 30 min. The optimal carbonization conditions were as follows: ammonia concentration 15 mL, CO2 flow rate 80 mL/min, carbonization temperature 30 ℃, carbonization time 60 min. The crystal phase of the product was vaterite, and the morphology of the product was spherical. After 8 cycles of sodium acetate auxiliaries, the reaction efficiency of calcium carbonate production was 57.8% after two cycles of sodium acetate auxiliaries. This study provides a new method for phosphogypsum comprehensive utilization and calcium carbonate production.

     

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