Sustained Bauxite Residue Rehabilitation with Gypsum and Organic Matter 16 years after Initial Treatment
Sustained Bauxite Residue Rehabilitation with Gypsum and Organic Matter 16 years after Initial Treatment
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DOI：
10.1021/acs.est.7b03568
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发表时间：
2018-01-02
影响因子：
11.4
通讯作者：
Burke, Ian T.
中科院分区：
文献类型：
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作者：
Bray, Andrew W.;Stewart, Douglas I.;Burke, Ian T.
铝土矿渣是氧化铝生产过程中的一种高容量副产品，通常在专门建造的铝土矿渣处置区（BRDAs）进行处置。与铝土矿残渣相互作用的天然沃茨具有高碱性的特征，并且具有高浓度的Na、Al和其它痕量金属。因此，重建BRDA的费用往往很高，而且需要大量资源/基础设施。数据来自20年前沉积的铝土矿残渣的三个相邻地块。一个地块在16年前用工艺砂、有机物、石膏和播种（完全处理）进行了修改，另一个地块在16年前用工艺砂、有机物和播种（部分处理）进行了修改，第三个地块未经处理。这些表面处理降低了碱度和盐度，从而产生了更适合于从播种生物定殖的基质。pH值的降低导致更低的Al，V，和作为流动性的积极处理的残留物和治疗的有益效果被动地延伸到20-30厘米以下的深度的原始修正案。这些积极的康复效果保持20年后，由于存在一个积极的和有弹性的生物群落。这种处理可以为布尔达使用结束关闭计划和孤立布尔达康复提供成本较低的解决方案。
Bauxite residue is a high volume byproduct of alumina manufacture which is commonly disposed of in purpose-built bauxite residue disposal areas (BRDAs). Natural waters interacting with bauxite residue are characteristically highly alkaline, and have elevated concentrations of Na, Al, and other trace metals. Rehabilitation of BRDAs is therefore often costly and resource/infrastructure intensive. Data is presented from three neighboring plots of bauxite residue that was deposited 20 years ago. One plot was amended 16 years ago with process sand, organic matter, gypsum, and seeded (fully treated), another plot was amended 16 years ago with process sand, organic matter, and seeded (partially treated), and a third plot was left untreated.. These surface treatments lower alkalinity and salinity, and thus produce a substrate more suitable for biological colonisation from seeding. The reduction of pH leads to much lower Al, V, and As mobility in the actively treated residue and the beneficial effects of treatment extend passively 20-30 cm below the depth of the original amendment. These positive rehabilitation effects are maintained after 2 decades due to the presence of an active and resilient biological community. This treatment may provide a lower cost solution to BRDA end of use closure plans and orphaned BRDA rehabilitation.