以气态硫磺还原磷石膏作全钙源制备贝利特硫铝酸盐水泥

Preparation of Belite Sulfoaluminate Cement Using Phosphogypsum Reduced by Gaseous Sulphur as Sole Calcium Oxide Source

关键词:  磷石膏  熟料烧成  矿物组成  贝利特硫铝酸盐水泥

Key words:  phosphogypsum  clinker firing  mineral composition  belite sulfoaluminate cement

摘要:

以气态硫磺还原磷石膏（PG）作为全钙源，采用分段煅烧制度制备了贝利特硫铝酸盐水泥，并采用X射线衍射仪、傅里叶红外光谱仪等研究了其矿物相组成与水化性能.结果表明：贝利特硫铝酸盐水泥的主要矿物相为Ca₄Al₆（SO₄）O₁₂（C₄A₃S¯）、Ca₂SiO₄（β-C₂S）和Ca₈Fe₄Al₄O₂₀（C₄AF），同时含有少量的钙铝黄长石（C₂AS）和alpha'-Ca₂SiO₄·0.05Ca₃（PO₄）₂（α'-C₂S）；随着煅烧温度和煅烧时间的增加，C₄A₃S¯的含量增加，但煅烧温度超过1 300 ℃，煅烧时间超过90 min后会对C₄A₃S¯的形成产生不利的影响；过度煅烧熟料各龄期的强度都会降低，对其早期强度的发展产生了不利的影响，但对其后期强度的发展有利.

Abstract:

Belite sulfoaluminate cement was prepared by the segmental calcination system using phosphogypsum （PG） reduced by sulfur gas as the sole calcium oxide source. The mineral phase composition and hydration properties were studied by X-ray differaction and Fourier infrared spectrum. The results show that main mineral phases of the clinker are Ca₄Al₆（SO₄）O₁₂（C₄A₃S¯），Ca₂SiO₄（β-C₂S） and Ca₈Fe₄Al₄O₂₀（C₄AF）， with small amounts of gehlenite（C₂AS） and alpha'-Ca₂SiO₄·0.05Ca₃（PO₄）₂（α'-C₂S）. When the calcination temperature and calcination time are increased， the content of C₄A₃S¯ increases. However， above 1 300 °C and 90 min， the formation of C₄A₃S¯ is adversely affected. Excessive calcination will reduce the strength of the clinker at each age， which is disadvantageous for its early strength development and is beneficial to its later strength development.