木质纤维素废渣对赤泥的脱碱及改良研究

Studies of Lignocellulose Waste Residue on Dealkalization and Amendment of Red Mud

赤泥是铝土矿提炼氧化铝后排放的强碱性废渣,数量巨大且环境风险大,如何无害化及土壤化处置是赤泥生态修复与治理的关键。该研究通过掺拌不同比例的木质纤维素酸性废渣,并进行复合微生物菌剂添加和覆叶排碱处理,对赤泥的pH、有机质含量及有效水容量进行了比较研究。发现掺拌木质纤维素废渣、添加复合微生物菌剂均能显著降低赤泥pH、增加有机质含量与有效水容量。其中添加复合微生物菌剂且赤泥与木质纤维素废渣质量比为7∶3时,赤泥pH可由11.08降至8.35,有机质含量由6.13 g/kg增至24.92 g/kg,有效水容量由8.80%增至19.17%,已达到一些耐盐碱植物的生长要求。覆叶排碱措施尽管对赤泥pH、有机质含量及有效水容量均无显著影响,但减少了可溶盐碱在赤泥表层的析出。故此,掺拌一定量的木质纤维素废渣并辅之以复合微生物菌剂添加及松叶覆盖等,是一种有效的"以废治废"的赤泥脱碱及改良方法。

Red mud is a waste residue with strong alkalinity after extracting alumina from bauxite.Due to its huge production,appropriate ecological remediation and management have been a global environmental concern.In this study,we mixed different proportions of lignocellulose acid residue,and added compound microorganism ameliorant and capped with pine needles and drained,with the objective to find out the optimum combination for red mud dealkalization and amendment.The results showed lignocellulose waste residue integrated with compound microorganism ameliorant significantly reduced pH and increased organic matter content and available water capacity of red mud.When red mud was mixed lignocellulose residue with the proportion of 7∶3 and treated with microorganism ameliorant,its pH reduced from 11.08 to 8.35,organic matter increased from 6.13 g/kg to 24.92 g/kg,and available water capacity increased from 8.80%to 19.17%,which are suitable for the growth of most alkali-tolerant plants.Capping with pine needles and draining had no effect on pH,organic matter content and available water capacity of red mud,but they reduced the surface precipitation of soluble salt and alkali.Therefore,mixing with lignocellulose residue,in combination with compound microorganism ameliorant and needle mulches,will be a promising method for dealkalization and amendment of red mud based on the strategy of'waste controlling by waste'.