Zhu Feng, Huang Nan, Xue Shengguo, Hartley William, Li Yiwei, Zou Qi
School of Metallurgy and Environment, Central South University, Changsha, 410083, People's Republic of China.
South China Institute of Environmental Sciences, Ministry of Environmental Protection, Guangzhou, 510655, China.
Environ Sci Pollut Res Int. 2016 Dec;23(23):23867-23875. doi: 10.1007/s11356-016-7626-9. Epub 2016 Sep 15.
It is recognized that for successful establishment of a vegetation cover on bauxite residue disposal areas, soil formation and a greater understanding of the processes of soil development are crucial. The stability of microaggregates is a very important physical property that prevents erosion in bauxite residues. Samples were collected from a disposal area in Central China to determine not only the mechanism of aggregation but also clay dispersion. Colloidal stability was assessed by determining organic matter, carbonate, electrolyte, clay mineral, and iron-aluminum oxide forms, as these would contribute to their stability. Organic matter improved microaggregate stability by combining with clay particles and polyvalent cations to form macroaggregates. Polyvalent cations such as calcium had a positive effect on particle flocculation, while organic molecules were more effective at stabilizing microaggregates. Removal of salinity dispersed silt-size aggregates into clay-size aggregates and reduced microaggregate stability. Calcium improved particle aggregation, while sodium had the reverse effect. Quartz powder was added to the residues but did not show any cementing effect, while free and amorphous iron-aluminum oxides were effective binding agents for microaggregate formation. We propose that the presence of organic matter and polyvalent cations, together with incorporation of organic carbon and calcium minerals, may enhance the stability of this material and prove beneficial toward improving its physical condition.
人们认识到，要在铝土矿废渣处理区成功建立植被覆盖，土壤形成以及对土壤发育过程的更深入了解至关重要。微团聚体的稳定性是防止铝土矿废渣侵蚀的一项非常重要的物理性质。从中国中部的一个处理区采集了样本，以确定团聚机制以及黏土分散情况。通过测定有机质、碳酸盐、电解质、黏土矿物和铁铝氧化物形态来评估胶体稳定性，因为这些会影响其稳定性。有机质通过与黏土颗粒和多价阳离子结合形成大团聚体，从而提高微团聚体的稳定性。钙等多价阳离子对颗粒絮凝有积极作用，而有机分子在稳定微团聚体方面更有效。去除盐分可将粉砂大小的团聚体分散成黏土大小的团聚体，并降低微团聚体的稳定性。钙促进颗粒团聚，而钠则有相反作用。向废渣中添加石英粉但未显示出任何胶结作用，而游离态和无定形铁铝氧化物是微团聚体形成的有效粘结剂。我们认为，有机质和多价阳离子的存在，以及有机碳和钙矿物的掺入，可能会增强这种材料的稳定性，并有利于改善其物理状况。
