聚醋酸乙烯酯共聚乳液在菱铁尾矿土壤化改良中的应用

Application of PVAc Copolymerization Emulsion in Soil Improvement of Siderite Tailings

  • 摘要: 目前,尽管菱铁尾矿资源化利用方式很多,但实践中多数利用量较低,不能有效解决菱铁尾矿堆存问题。菱铁尾矿的土壤化利用是实现规模化利用、提高利用率的有效方式,但菱铁尾矿理化性质极不适宜植物的生长,故土壤化改良十分必要。本文将聚醋酸乙烯酯(PVAc)共聚乳液用于菱铁尾矿土壤化改良及生态修复,考察了PVAc共聚乳液对菱铁尾矿的固结强度、耐热老化和冻融稳定性、保水性能及处理后菱铁尾矿理化性质的影响,通过野外植物种植实验探究了PVAc共聚乳液处理菱铁尾矿后的生态效应。结果表明,使用质量浓度为2.0%的PVAc共聚乳液处理的菱铁尾矿土样固结强度达到0.47 MPa,可实现抑制菱铁尾矿扬尘的效果,且共聚乳液对菱铁尾砂具有优异的抗热老化及保水效果,有利于植物及微生物的生长。与未使用共聚乳液处理的菱铁尾矿相比,经PVAc共聚乳液处理后的菱铁尾矿pH由8.92下降至7.37,有机质含量从1.13 g/kg增加到4.52 g/kg,全氮含量由8.18增加至12.41 g/kg,且土样中大粒径组分出现明显的增加,从而降低了菱铁尾矿的盐碱化程度,提升了肥力与稳定性,且相比于现有的聚丙烯酰胺类修复剂而言,其使用成本可降低35%以上;另外,经2% PVAc共聚乳液处理后的菱铁尾矿,植物存活率达到70%以上,株高、茎生物量与根冠比均明显高于对照组,且微生物具有更好的生长态势,这表明PVAc共聚乳液用于菱铁尾矿土壤化改良具有良好的生态效果。

     

    Abstract: At present, although there were many ways to utilize the resources of siderite tailings, the utilization amount was relatively low and could not effectively solve the problem of siderite tailings storage. The soil utilization of siderite tailings has been an effective way to achieve large−scale utilization and improved utilization efficiency. However, the most significant problem with the soil utilization of siderite tailings was that their physical and chemical properties were extremely unsuitable for plant growth, so soil improvement was very necessary. In this paper, PVAc copolymerization emulsion was used for soil improvement and ecological restoration of siderite tailings. The effects of PVAc copolymerization emulsion on the consolidation strength, heat aging, freeze−thaw stability, water retention performance and physical and chemical properties of siderite tailings after treatment were investigated. The ecological effect of treating siderite tailings with PVAc copolymer emulsion was studied through field plant experiments. The research results show that the consolidation strength of PVAc copolymerization emulsion with a concentration of 2.0% on the siderite tailings soil sample reach 0.47 MPa, which could achieve the effect of inhibiting the dust of siderite tailings, and the copolymerization emulsion has more excellent heat aging resistance and water retention effect on the siderite tailings, which is conducive to the growth of plants and microorganisms. Compared with the siderite tailings treated without copolymerization emulsion, after treatment with PVAc copolymer emulsion, the pH of siderite tailings decreases from 8.92 to 7.37, the organic matter content increases from 1.13 to 4.52 g/kg, and the total nitrogen content rises from 8.18 to 12.41 g/kg. Additionally, the proportion of larger particle sizes in the soil samples show a significant increase, thereby reducing the salinization−alkalization degree of the siderite tailings while improving fertility and stability. Moreover, compared to existing polyacrylamide−based remediation agents, its usage cost can be reduced by more than 35%. Additionally, siderite tailings treated with a 2% PVAc copolymer emulsion achieve a plant survival rate of 70%, with plant height, stem biomass, and root−to−shoot ratio all significantly higher than those of the control group. Furthermore, the siderite tailings treated with 2% PVAc copolymerization emulsion had a better growth trend of microorganisms, which indicate that PVAc copolymerization emulsion has good ecological effect on the soil improvement of siderite tailings.

     

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