冷粘结磷石膏基集料造粒工艺优化研究

Optimization Study of Cold-bonded Phosphogypsum-based Aggregate Granulation Process

冷粘结磷石膏基集料具有良好的力学性能,可代替天然集料用于制备混凝土。已有研究表明,造粒工艺参数对集料性能有较大的影响。研究了含水率(21%~26%)、造粒时间(10~25 min)、转速(30~50 r/min)和倾角(40°~50°)对磷石膏基集料造粒效率、粒径分布和抗压强度的影响。结果表明,最佳含水率为22%~25%、造粒时间20 min达到强度饱和点,45°40r/min时集料具有较高的造粒效率和良好的粒径分布。然后,研究了水泥含量(1%~7%)对磷石膏基集料机械性能的影响,7 d单颗粒抗压强度最高可达2.86 MPa,28 d可达4.29 MPa,从早期强度和长期强度综合考虑,最佳水泥掺量为5%。

Phosphogypsum-based cold-bonded aggregates(PCBAs) have been shown to have good strength and can replace natural aggregates for the preparation of concrete.Previous studies have indicated that granulation process parameters have a significant impact on aggregate performance.This study investigated the effects of water content(21%~26%),granulation duration(10~25 min),rotary speed(30~50 r/min) and disc tilt angle(40°~50°) on the granulation efficiency,particle size distribution,and compressive strength of PCBAs were studied.The results show that the optimal water content is 22%~25%,the granulation duration reaches the saturation point in 20 min,and the aggregate has high granulation efficiency and good particle size distribution at 45°40 r/min.Subsequently,the effects of cement content(1%~7%) on the properties of PCBAs was also studied,the single aggregate compressive strength at 7 d can reach up to 2.86 MPa,and at 28 d it can reach 4.29 MPa.The optimal cement content was 5% from the comprehensive consideration of early strength and later strength.