Walling Sam A, Bernal Susan A, Gardner Laura J, Kinoshita Hajime, Provis John L
Immobilisation Science Laboratory, Department of Materials Science & Engineering, Sir Robert Hadfield Building, The University of Sheffield S1 3JD UK
RSC Adv. 2018 Jun 26;8(41):23101-23118. doi: 10.1039/c8ra03717e. eCollection 2018 Jun 21.
The structural evolution of a sodium carbonate activated slag cement blended with varying quantities of Mg(OH) was assessed. The main reaction products of these blended cements were a calcium-sodium aluminosilicate hydrate type gel, an Mg-Al layered double hydroxide with a hydrotalcite type structure, calcite, and a hydrous calcium aluminate phase (tentatively identified as a carbonate-containing AFm structure), in proportions which varied with NaO/slag ratios. Particles of Mg(OH) do not chemically react within these cements. Instead, Mg(OH) acts as a filler accelerating the hardening of sodium carbonate activated slags. Although increased Mg(OH) replacement reduced the compressive strength of these cements, pastes with 50 wt% Mg(OH) still reached strengths of ∼21 MPa. The chemical and mechanical characteristics of sodium carbonate activated slag/Mg(OH) cements makes them a potentially suitable matrix for encapsulation of high loadings of Mg(OH)-bearing wastes such as Magnox sludge.
评估了掺有不同数量氢氧化镁（Mg(OH)₂）的碳酸钠激发矿渣水泥的结构演变。这些混合水泥的主要反应产物是钙钠铝硅酸盐水合物型凝胶、具有水滑石型结构的Mg-Al层状双氢氧化物、方解石和含水铝酸钙相（初步鉴定为含碳酸盐的AFm结构），其比例随Na₂O/矿渣比而变化。Mg(OH)₂颗粒在这些水泥中不发生化学反应。相反，Mg(OH)₂起到填充剂的作用，加速碳酸钠激发矿渣的硬化。尽管增加Mg(OH)₂替代量会降低这些水泥的抗压强度，但含有50 wt% Mg(OH)₂的浆体仍能达到约21 MPa的强度。碳酸钠激发矿渣/Mg(OH)₂水泥的化学和力学特性使其成为潜在适合封装高负荷含Mg(OH)₂废物（如镁诺克斯污泥）的基质。
