高岭土尾砂制备混凝土活性掺合料的试验研究

Experimental Study on Preparation of Concrete Reactive Admixture with Kaolin Tailings

高岭土尾砂是高岭土矿精选后产生的固体废弃物。采用机械球磨机以及添加化学活性激发剂对高岭土尾砂活化后作混凝土掺合料的可行性进行了初步研究。结果表明添加化学活性激发剂再细磨能够使尾砂活性得到显著提高,激发剂中含有CaO,Ca(OH)2为必要条件,含有硫酸盐Na2SO4,CaSO4为充分条件;混凝土中用20%～30%活化后的尾砂超量取代10%～20%水泥,在不影响混凝土流动性的情况下,取代后与取代前的混凝土28 d抗压强度比达97%。该方法不仅可减少水泥用量,降低工程造价,还能使尾砂变废为宝,减少占地及环境污染,具有显著的经济效益与社会效益。

Kaolin tailing is a kind of solid waste generated from mineral separation.The concrete admixture prepared with kaolin tailing through mechanical milling and the addition of chemical activator was primary researched.The results show that the activity of kaolin tailing can be increased dramatically through adding the chemical activator,where the activator must contain CaO or Ca（OH）2,and can include Na2SO4 or CaSO4,selectively.The 28-day compressive strength ratio of concretes reaches up to 97% after 20%~30% reactive kaolin tailing replace 10%~20% cement,and then the workability of concrete will not be affected.This technique not only reduces the amount of cement and engineering cost,but also changs waste into valuables and prevents environmental pollution with significant economic and social benefits.