Mineral wools are the most widely used building insulation material worldwide. Annually, 2.5 million tonnes of mineral wool waste are generated in the EU alone, and this is a largely unutilised material that is landfilled or incinerated. However, mineral wool wastes are promising precursors for production of alkali-activated cementitious binders due to their favourable chemical and mineralogical composition and high surface area. Alkali-activation is therefore a valuable route for valorisation of large quantities of mineral wool waste. This study resolves the phase assemblage and nanostructure of reaction products formed upon alkali activation of stone wool and glass wool by sodium hydroxide and sodium silicate solutions with X-ray diffraction, electron microscopy and solid state nuclear magnetic resonance spectroscopy experiments probing ²⁷Al and ²⁹Si. The stone wool-based alkali-activated binder comprises an amorphous sodium- and aluminium-substituted calcium silicate hydrate (C-(N-)A-S-H) gel, an amorphous sodium aluminosilicate hydrate (N-A-S-H) gel and small amounts of the layered double hydroxide phase quintinite and zeolite F. The glass wool-based alkali-activated binder comprises an amorphous Ca- and Al-substituted sodium silicate (N-(C-)(A-)S–H) gel. Gel chemical composition and reaction kinetics of alkali-activated mineral wools are shown to be dependent on the activating solution chemistry, with reaction rate and extent promoted by inclusion of a source of soluble Si in the reaction mixture. This work provides the most advanced description of the chemistry and structure of alkali-activated mineral wools to date, yielding new insight that is essential in developing valorisation pathways for mineral wools by alkali activation and providing significant impetus for development of sustainable construction materials.

矿棉是全球使用最广泛的建筑保温材料。仅在欧盟，每年就产生250万吨矿棉废物，这是一种主要未被利用的材料，被填埋或焚化。然而，矿棉废料由于其有利的化学和矿物学组成以及高表面积而成为用于生产碱活化水泥基粘结剂的有前途的前体。因此，碱活化是大量矿棉废料增值的一条有价值的途径。本研究通过X射线衍射，电子显微镜和固态核磁共振光谱实验，解决了氢氧化钠和硅酸钠溶液对石棉和玻璃棉进行碱活化后形成的反应产物的相组装和纳米结构。²⁷ Al和²⁹硅。岩棉基碱活化的粘合剂包括无定形的钠和铝取代的硅酸钙水合物（C-（N-）ASH）凝胶，无定形的硅铝酸钠水合物（NASH）凝胶和少量的层状双氢氧化物相硅藻土和沸石F。基于玻璃棉的碱活化粘合剂包括无定形的Ca和Al取代的硅酸钠（N-（C-）（A-）S–H）凝胶。已显示碱活化的矿棉的凝胶化学组成和反应动力学取决于活化溶液的化学性质，反应速率和程度通过在反应混合物中包含可溶性硅源来促进。这项工作提供了迄今为止有关碱活化矿棉的化学和结构的最高级描述，