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Influence of calcium hydroxide addition on arsenic leaching and solidification/stabilisation behaviour of metallurgical-slag-based green mining fill.
Journal of Hazardous Materials ( IF 12.2 ) Pub Date : 2020-01-22 , DOI: 10.1016/j.jhazmat.2020.122161
Yuying Zhang 1 , Wei Gao 2 , Wen Ni 1 , Siqi Zhang 1 , Yunyun Li 1 , Ke Wang 1 , Xiaohui Huang 1 , Pingfeng Fu 3 , Wentao Hu 3
Affiliation  

In this study, metallurgical-slag-based binder (MSB) with different dosages of calcium hydroxide (CH) was mixed with high-arsenic-containing mine tailings (HAMT) to form green mining fill samples (GMFs) for As solidification/stabilisation (S/S). The As leaching characteristics of the GMFs were evaluated using pH-dependent leaching tests, semi-dynamic leaching tests and toxicity leaching tests. The effective diffusion coefficient (De) decreased from 6.98 × 10-14 to 5.90 × 10-15 cm2/s and the leachability index (LI) increased from 13.53 to 14.73 after 3 wt.% CH was added to the GMFs. The GMFs containing 0 wt.% CH (GMF-0C) and those containing 3 wt.% CH (GMF-3C) reached pH = 2 with acid addition amounts of 9.0 meq/g-dry and 9.3 meq/g-dry at 90 d curing time, and the maximum As leaching concentrations of GMF-0C and GMF-3C reached 10.47 mg/L and 7.47 mg/L, respectively, indicating that GMF-3C exhibited better acid neutralisation and As retention capacities than GMF-0C. Further, a Tescan Integrated Mineral Analyser (TIMA) was used to analyse the dominant hydration products of GMF-3C, which revealed that calcium silicate hydrate, CASH, ettringite and zeolite phases represented approximately 22.5 wt.% of the products. These results provide an understanding regarding the safe large-scale utilisation of GMFs.

中文翻译:

氢氧化钙的添加对冶金矿渣基绿色矿渣中砷的浸出和凝固/稳定行为的影响。

在这项研究中,将具有不同剂量氢氧化钙(CH)的冶金渣基粘结剂(MSB)与含高砷的矿尾矿(HAMT)混合以形成绿色矿渣填充样品(GMF),以进行固化/稳定化( S / S)。使用pH依赖的浸出试验,半动态浸出试验和毒性浸出试验评估了GMF的As浸出特性。在将3%(重量)的CH添加到GMF中后,有效扩散系数(De)从6.98×10-14降低到5.90×10-15 cm2 / s,浸出指数(LI)从13.53增加到14.73。含0重量%CH(GMF-0C)和含3重量%CH(GMF-3C)的GMF在90的酸添加量为9.0 meq / g-干和9.3 meq / g-干时达到pH = 2 d固化时间,GMF-0C和GMF-3C的最大As浸出浓度分别达到10.47 mg / L和7。分别为47 mg / L,表明GMF-3C具有比GMF-0C更好的酸中和和As保留能力。此外,使用Tescan综合矿物分析仪(TIMA)分析了GMF-3C的主要水合产物,这表明硅酸钙水合物,CASH,钙矾石和沸石相占产物的约22.5重量%。这些结果提供了关于安全大规模使用GMF的理解。
更新日期:2020-01-22
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