酸雨浸泡对铬渣中六价铬的释放影响

Influence of acid rain marination on Cr^(6+) release in chromium slag

对堆放的不同年代铬渣,模拟不同pH的酸雨进行了浸泡实验。结果表明,不同年代铬渣均具有很强的腐蚀性,pH达到12以上。由于受生产工艺以及堆放时间的影响,不同年代铬渣中的铬含量并不是简单地随堆放时间的增长而变少,铬渣中总铬和六价铬的质量分数范围分别为4.68%~4.86%和1.19%~1.73%。在相同年代的铬渣中,铬的浸出质量浓度随酸雨pH的减小而增大,且趋势明显;不同年代铬渣中铬的浸出浓度主要受到铬渣中六价铬的影响,且随着铬渣中六价铬质量分数的增长而增大。浸泡时间与铬浸出质量浓度之间的关系以指数函数的拟合效果最好。不同年代的铬渣在不同pH酸雨浸泡下,浸泡液质量浓度均远高于排放质量浓度标准,对水环境产生严重的影响。

Marinating experiments have been made on chromium slag of diverse years, by simulating acid rain with different pH values. Results showed that all the chromium slag of diverse years is very corrosive and the pH value can reach 12 above. Because of the influence of production process and stack time ,the Cr content in chromium slag of diverse years didn＇t simply decrease with stack time grows. The mass fraction of total chromium （ TCr） and Cr^6＋ in chromium slag range from 4.68% -4.86% and 1.19% - 1.73 % respectively. For chromium slags of the same year,the Cr marinating mass concentration increases with the decreasing of pH value of acid rain and the trend is obvious;whereas for the chromium slags of different years,marinating mass concentration of Cr is mainly affected by Cr^6＋ in chromium slag and it increases with the growth of mass concentration of Cr^6＋ . The relation of marinating mass concentration of Cr and marinating time can be properly expressed by the formula of y = α · e^bx. In any case after the chromium slag marinated by the acid rain with any pH value its soaking liquid＇s Cr mass concentration all exceeds the effluent standard which would affect water environment seriouslv.