Modified granulation of red mud by weak gelling and its application to stabilization of Pb.
Modified granulation of red mud by weak gelling and its application to stabilization of Pb.
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DOI：
10.1016/j.jhazmat.2012.05.046
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发表时间：
2012-08
影响因子：
13.6
通讯作者：
Huili Luo;Sheng Huang;Lin Luo;Gen-yi Wu;Yan Liu
中科院分区：
文献类型：
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作者：
Huili Luo;Sheng Huang;Lin Luo;Gen-yi Wu;Yan Liu
采用转鼓造粒法对赤泥进行部分水化改性。采用外加剂和表面活性剂改善赤泥基颗粒料的微孔结构，以达到稳定Pb的目的。通过XRD和SEM-EDS分析，证明了RM中的主要碱金属方解石被部分凝固和包覆。与RM的pH 12.47相比，颗粒的最低pH为10.66，这意味着水解和分解释放的OH−减少。通过对土壤中铅的稳定性、对土壤性质的影响及成型质量的综合分析，确定了颗粒PSP的最佳配方为：水泥5%、石膏5%、稻草1%、乳化剂OP-10 0.1%。在90d的修复过程中，以5%PSP2替代500 mgkg-1 Pb污染的人工土壤，第30天Pb的固定量为9.85mgkg-1。当终浓度为11.13mgkg-1时，反作用减弱，而RM的终浓度为14.25mgkg-1。铅残留量提高122.61%，优于RM的83.92%。特别是，在矿山土壤中的pH值最高值为11.09，在第1天与RM，但离子铅下降了46.26%。同时，与颗粒相比，与对照土壤Zeta电位的显著偏离持续时间更长，恢复更困难。因此，RM的颗粒化改性被证明是非常重要的，目的是稳定释放OH−，以提高铅的后期稳定性。
This study presents a novel modification of red mud (RM) with cementitious materials by rotary drum granulation under partial hydration. Admixtures and surfactants were applied to improve the microspore structure of red mud-based granules in order to stabilize Pb steadily. Through XRD and SEM-EDS analyses, it was demonstrated that calcite, the main alkali in RM, was partially concreted and coated. Compared to pH 12.47 for RM, the lowest pH of the granules was 10.66 implying that the release of OH−from hydrolysis and decomposition was decreased. Based on stabilization of Pb, influence on soil properties and forming qualities, composition of the optimum granule PSP was determined as 5% cement, 5% gypsum, 1% rice straw, and 0.1% emulsifier OP-10. Within a 90d remediation, immobilization of ionic Pb in a 500mgkg−1Pb-contaminated artificial soil was 9.85mgkg−1at day 30 with 5% PSP2 as substitute. Furthermore, the reverse increase diminished as the final concentration was 11.13mgkg−1while it was 14.25mgkg−1by RM. The increase of residual Pb was 122.61%, which was better than the 83.92% of RM. Particularly, the highest pH in mine soil was 11.09 at day 1 with RM, but the decrease of ionic Pb was 46.26%. Meanwhile, a significant deviation from the control soil zeta-potential lasted longer and the recovery was more difficult, as compared to the granules. Therefore, a granulated modification of RM is shown to be very important when aiming at steady release of OH−to improve the later stabilization of Pb.