水泥磷渣粉稳定磷尾矿-废石路面基层材料的研究

Study on Stabilizing Phosphorus Tailing-waste Rock Road Base Material with Cement Phosphorus Slag Power

为了提高我国磷尾矿和废石等矿业废弃物综合利用率,采用间断级配并结合体积法设计磷尾矿-废石矿质混合料的级配,并以磷渣粉作为辅助胶凝材料,制备出水泥磷渣粉综合稳定磷尾矿-废石的半刚性基层材料。研究结果表明:优化后配合比为水泥∶磷渣粉∶矿质混合料=5∶6∶89,其中矿质混合料为磷尾矿∶废石=40∶60组成的间断级配,试件7d无侧限抗压强度代表值达到4.35MPa,满足重交通高速公路和一级公路路面基层材料的标准要求;且具有良好的耐久性以及无重金属离子浸出;SEM微观分析表明,磷渣粉在水泥水化产物Ca(OH)2的激发作用下发生火山灰反应,形成C-S-H凝胶和钙矾石等产物,并随着水化龄期延长,水化产物大量生成并交叉联结,形成致密结构有利于路面基层材料的后期强度增长。

In order to improve the comprehensive utilization rate of mining wastes such as phosphorus tailings and waste rocks in China,the gradation of mineral mixture of phosphorus tailings and waste rocks was designed by intermittent gradation combined with volume method,and the semi-rigid base material of phosphorus tailings and waste rocks was prepared by using phosphorus slag powder as auxiliary cementing material.The experimental results show that the optimized mixing ratio is cement∶phosphorus slag powder∶Mineral mixture=5∶6∶89,in which the mineral mixture is discontinuous gradation composed of phosphorus tailings and waste rock=40∶60,and the representative value of 7 dunconfined compressive strength of the specimen reaches 4.35 MPa,which meets the standard requirements of pavement base materials of heavy traffic expressways and first-class highways,meanwhile it has good durability and no leaching of heavy metal ions.SEM analysis shows that under the excitation of cement hydration product Ca(OH)2,phosphorus slag powder undergoes pozzolanic reaction,forming products such as C-S-H gel and ettringite.With the prolonging of hydration age,a large number of hydration products are generated and cross-linked,forming a dense structure which is beneficial to the later strength growth of pavement base materials.