热活化中级铝硅比煤矸石对复合水泥性能及水化的影响

Effect of Thermal Activated Coal Gangue with Intermediate Al_(2)O_(3)/SiO_(2) Mass Ratio on the Performance and Hydration of Compound Cement

为推进煤矸石的综合利用,提出对中级硅铝比新采/堆存煤矸石进行煅烧活化,并利用活化产物配制低熟料复合硅酸盐水泥,研究了活化煤矸石对复合水泥性能及水化的影响。结果表明:提高煅烧温度对新采煤矸石活性发挥更为有利,800℃煅烧活化1 h其活性指数达到86%;堆存煤矸石经历了自燃过程,不经煅烧或低温煅烧即具备较高活性,600℃煅烧活化1 h其活性指数达到89%。以熟料、活化新采/堆存煤矸石、石灰石、磷石膏的质量比50∶30∶15∶5配制复合水泥,其28 d抗压强度分别为36.7 MPa和32.1 MPa。由于活化煤矸石颗粒疏松多孔且保留了黏土矿物层状结构,故复合水泥密度低、比表面积大、标准稠度需水量高、凝结时间长,其力学性能发展较为缓慢。进一步提高复合水泥中熟料用量,水泥力学性能提高,当熟料质量分数为70%时,所配制复合水泥力学性能可达到GB 175《通用硅酸盐水泥》中P.C 42.5等级。

In order to promote the comprehensive utilization of coal gangue,calcination activation of newly mined/deposited coal gangue with intermediate Al_(2)O_(3)/SiO_(2) mass ratio was proposed,and the thermal activated products were used to prepare compound Portland cement with low clinker content.The influence of activated coal gangue on the properties and hydration of composite cement was studied.The results show that increasing calcination temperature is beneficial to the activity improvement of fresh gangue,with an activity index of 86%after calcination at 800℃for 1 h.The stocked coal gangue undergoes a spontaneous combustion process and exhibits high activity without calcination or through low-temperature activation.And its activity index reaches 89%after calcination and activation at 600℃for 1 h.The composite cement is prepared with the mass ratio of 50∶30∶15∶5 of clinker,activated newly mined/stockpiled coal gangue,limestone and phosphogypsum,and their 28 d compressive strength is 36.7 MPa and 32.1 MPa,respectively.The compound cement exhibits low density,large specific surface area,high water requirement for standard consistency and long setting time and its mechanical properties develop slowly due to the loose and porous particles and the retained layer structures in active gangue.Further increasing the amount of clinker in composite cement can improve the mechanical properties of the cement.When the amount of clinker is 70%,the mechanical properties of the prepared composite cement can reach the P.C 42.5 grade in GB 175“Common Portland Cement”.