固废基硅酸盐水泥熟料矿物相的钠取代倾向

Sodium Incorporation Behavior in Mineral Phases of Solid Waste Based Portland Cement Clinker

摘要:

采用电石渣、赤泥和硅灰等工业固废制备了固废基硅酸盐水泥熟料（SWCC），研究了Na⁺在主要熟料相中的掺杂机理。结果表明：SWCC的主要矿物相由68.3%的硅酸二钙（β-C₂S）、21.0%的铁铝酸四钙（C₄AF）、6.6%的铝酸三钙（C₃A）及少量硅酸三钙（C₃S）组成，该水泥熟料添加8%脱硫石膏后， 28 d抗压强度为16.7 MPa；Na⁺容易被熟料中的含铁矿物相固溶，且倾向于取代Ca²⁺，但难固溶于C₂S，尤其难以取代C₂S的Si⁴⁺；除了Si原子，Na原子与宿主原子（Al、Fe、Ca）形成相同的配位数，仅引起局部结构畸变，这种畸变体现在局部键合结构中，而不是整体晶体变形中。

Abstract:

The solid waste based Portland cement clinker （SWCC） prepared by industrial solid wastes such as carbide slag， red mud， and silica fume， were utilized to investigate the doping mechanism of sodium ions in the major clinker phases. The results show that the main mineral phases of SWCC consist of 68.3% belite （β-C₂S）， 21.0% brownmillerite （C₄AF）， 6.6% tricalcium aluminate （C₃A）， and a small amount of alite （C₃S）. When 8% desulfurized gypsum is added to this clinker， the 28 d compressive strength reaches 16.7 MPa. Na⁺ is easily incorporated into the iron-containing mineral phases of the clinker， preferentially substituting for Ca²⁺， but exhibites limited solid solubility in C₂S， particularly in replacing Si⁴⁺ in C₂S. Except for Si atoms， Na atoms form the same coordination number as the host atoms （Al， Fe， Ca）， inducing only localized structural distortions. These distortions are manifested in the local bonding environment rather than in the overall crystal deformation.