摘要:
以承德地区的钒钛磁铁矿选铁尾矿为主要原料制备了加气混凝土砌块,研究了尾矿细度及添加量对制品干密度与抗压强度的影响,采用XRD和SEM分析了尾矿添加量调控样品相组成与显微结构的机理,检测了制品的吸水率与耐水性等相关性能。结果表明:尾矿经球磨20 min后,-0.074μm颗粒含量增至90.23%。提高尾矿细度增大了样品的致密度,引入尾矿使样品的干密度与抗压强度先增大后减小。采用尾矿(球磨20 min)∶水泥∶石灰∶石膏=60∶20∶15∶5的工艺条件,制备出加气混凝土砌块的抗压强度大于4.0 MPa,干密度小于595 kg·m-3,综合性能满足GB11968—2006标准中A4.5等级的要求。XRD与SEM分析表明,添加40%~60%尾矿有利于生成C-S-H凝胶与托贝莫来石。两者相互胶结,使制品具有较高的强度,较优的吸水率及耐水性。
Abstract:
Aerated concrete blocks were prepared from vanadium-titanium magnetite tailings after iron separation from Chengde.The fineness and addition effects of tailing on dry density and compressive strength of samples were studied.The phase compositions and microstructures of samples by tailing addition were analyzed by XRD and SEM,and the water absorption and water resistance of the products were tested.The results show that the content of-0.074 μm particles reaches to 90.23% after 20 min of milling.Increasing the tailing fineness enhances the density of samples,and the dry density and compressive strength of samples firstly increase and then decrease with increasing tailing addition.Under the condition of tailing（grinding for 20 min）∶cement∶lime∶gypsum = 60∶20∶15∶5,the obtained aerated concrete block has a compressive strength more than 4.0 MPa and a dry density less than 595 kg·m-3,which meets requirement of A4.5 grade of GB11968—2006 standard.XRD and SEM analysis show that adding 40%～60% tailing is beneficial to the formation of C-S-H gel and tobermorite,endowing the product with high strength,good water absorption and water resistance.
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