海水拌和多元固废浆料的性能及微观结构

Performance and Microstructure of Multi-solid Waste Grouts Mixed with Seawater

摘要:

为解决传统水泥注浆材料高成本、高碳排的问题，研发了一种海水拌和多元固废（包括铅锌尾矿、碱渣和粉煤灰）的新型注浆材料，分析了配合比对浆料稠度、析水率、凝结时间和抗压强度的影响，并结合一系列表征技术探究浆料中凝胶产物的组成和微观形貌。结果表明：海水与碱渣可加速体系的水化反应并产生丰富的水化产物，而铅锌尾矿中重金属会抑制水化产物的生成；海水拌和浆料表现出较低重金属浸出性。其中掺有40%铅锌尾矿、48%碱渣和12%粉煤灰的浆料性能最佳，与纯水拌和相比，海水拌和浆料的稠度、初凝与终凝时间和析水率均有所下降，分别为96.3 mm、8.6 h、14.2 h和0.83%，而其28 d抗压强度可达3.17 MPa，且重金属浸出浓度低于限值。

Abstract:

To address the high cost and carbon emissions associated with traditional cement-based grouts， a novel grout was developed using seawater and multiple solid wastes （including lead-zinc tailings， soda residue， and fly ash）. The influence of the mix proportions on the consistency， bleeding rate， setting time and compressive strength of the grout was analyzed. Combined with a series of characterization techniques， the composition and microstructure of the gel products in the grout were identified. The results indicate that seawater and soda residue accelerate the hydration reaction of the system and promote the formation of abundant hydration products. Conversely， heavy metals present in the lead-zinc tailings inhibit the formation of hydration products. The grout mixed with seawater exhibits low heavy metal leaching properties. Among all formulations， the grout comprising 40% lead-zinc tailings， 48% soda residue， and 12% fly ash exhibits optimal performance. Relative to the grout mixed with deionized water， the seawater mixed grout shows decreases in consistency， initial， final setting time and bleeding rate to 96.3 mm， 8.6 h， 14.2 h and 0.83%， respectively. Its 28 d compressive strength reaches 3.17 MPa， and the concentrations of leached heavy metals remains well below regulatory limits.