Abstract The main objective of this paper was to investigate the alkali activation of mine tailings (MT) after mechanochemical activation and the effect of metakaolin (MK) addition. Finnish mica-rich tailings from a phosphate mine were studied as precursors for alkali-activated materials (AAM) with a potential application as a substitute for ordinary Portland cement (OPC). The principal physical properties (water absorption, apparent porosity and unconfined compressive strength) were measured for samples containing 30% to 70% tailings. Zeolite phases such as natrolite and cancrinite were observed and the formation of C-(N)-A-S-H 1 and N-A-S-H gels was identified by XRD, DRIFT, FESEM-EDS and NMR technologies. A life cycle assessment (LCA) was conducted on specimens in comparison to OPC. This work indicated that phosphate MT can be recycled through alkali activation with lower CO2 emission compared to all-metakaolin geopolymers and that the binder phase formed at the most promising tailings contents (60– 70%) was C-(N)-A-S-H gel.

中文翻译：

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在碱活化复合材料中回收云母和富含碳酸盐的尾矿：与偏高岭土的协同作用

摘要 本文的主要目的是研究机械化学活化后尾矿（MT）的碱活化和偏高岭土（MK）添加的影响。研究了来自磷矿的芬兰富含云母的尾矿作为碱活化材料 (AAM) 的前体，具有作为普通波特兰水泥 (OPC) 替代品的潜在应用。对含有 30% 至 70% 尾矿的样品测量了主要物理特性（吸水率、表观孔隙率和无侧限抗压强度）。通过XRD、DRIFT、FESEM-EDS和NMR技术观察到沸石相如钠沸石和钙沸石，并鉴定了C-(N)-ASH 1和NASH凝胶的形成。与 OPC 相比，对样本进行了生命周期评估 (LCA)。