Department of Chemistry, The University of Sheffield, Dainton Building, Brook Hill, Sheffield, S3 7HF, UK.
Department of Civil and Structural Engineering, The University of Sheffield, Sir Frederick Mappin Building, Sheffield, S1 3JD, UK.
Sci Rep. 2022 Feb 21;12(1):2880. doi: 10.1038/s41598-022-06374-6.
Water scarcity in semi-arid/arid regions is driving the use of salt water in mining operations. A consequence of this shift, is the potentially unheeded effect upon Mine Tailing (MT) management. With existing stabilization/solidification methodologies exhibiting vulnerability to MT toxicity and salinity effects, it is essential to explore the scope for more environmentally durable sustainable alternatives under these conditions. Within this study we investigate the effects of salinity (NaCl, 0-2.5 M) and temperatures associated with arid regions (25 °C, 40 °C), on Locust Bean Gum (LB) biopolymer stabilization of MT exemplar and sand (control) soil systems. A cross-disciplinary 'micro to macro' pipeline is employed, from a Membrane Enabled Bio-mineral Affinity Screen (MEBAS), to Mineral Binding Characterisation (MBC), leading finally to Geotechnical Verification (GV). As predicted by higher FeO LB binding affinity in saline in the MEBAS studies, LB with 1.25 M NaCl, results in the greatest soil strength in the MT exemplar after 7 days of curing at 40 °C. Under these most challenging conditions for other soil strengthening systems, an overall UCS peak of 5033 kPa is achieved. MBC shows the critical and direct relationship between FeO-LB in saltwater to be 'high-affinity' at the molecular level and 'high-strength' achieved at the geotechnical level. This is attributed to biopolymer binding group's increased availability, with their 'salting-in' as NaCl concentrations rises to 1.25 M and then 'salting-out' at higher concentrations. This study highlights the potential of biopolymers as robust, sustainable, soil stabilization additives in challenging environments.
半干旱/干旱地区的水资源短缺正在推动采矿作业中使用盐水。这种转变的一个后果是，可能会忽视矿山尾矿（MT）管理的潜在影响。由于现有的稳定/固化方法对 MT 的毒性和盐度效应表现出脆弱性，因此在这些条件下探索更具环境耐久性的可持续替代方案至关重要。在本研究中，我们研究了盐分（NaCl，0-2.5 M）和与干旱地区相关的温度（25°C，40°C）对豆胶（LB）生物聚合物稳定 MT 标本和沙（对照）土壤系统的影响。采用了一种跨学科的“从微观到宏观”的方法，从膜增强生物矿物亲和筛选（MEBAS）到矿物结合特性（MBC），最后到岩土验证（GV）。正如 MEBAS 研究中预测的那样，在盐水中 LB 与 FeO 结合的亲和力更高，在 40°C 下固化 7 天后，LB 与 1.25 M NaCl 一起导致 MT 标本中的土壤强度最大。在对其他土壤增强系统最具挑战性的条件下，总体 UCS 峰值达到 5033 kPa。MBC 显示出 FeO-LB 在盐水中的关键和直接关系在分子水平上是“高亲和力”，在岩土水平上是“高强度”。这归因于生物聚合物结合基团的可用性增加，随着 NaCl 浓度升高至 1.25 M，它们的“盐溶”，然后在更高的浓度下“盐析”。本研究强调了生物聚合物作为在具有挑战性的环境中具有强大、可持续的土壤稳定添加剂的潜力。
