高炉渣资源化生产绿色建材的环境效益评估——基于生命周期的视角

高炉渣是钢铁厂高炉炼铁产生的矿渣,具有较高的资源化价值,可用于生产多种绿色建材产品。熔融高炉渣经水急冷后形成的粒化高炉矿渣,粉磨成矿渣微粉可作为水泥混合材和混凝土掺合料。以高炉渣资源化过程为研究对象,采用生命周期清单分析方法,并基于GaBi 4软件平台,对我国某建材企业综合利用高炉渣生产矿渣硅酸盐水泥和商品混凝土全过程的能源消耗、原材料消耗和温室气体排放进行了分析,进而从节能、降耗和碳减排三方面评估其环境效益。结果表明,与普通硅酸盐水泥相比,矿渣硅酸盐水泥可分别实现节约能源1 911 MJ/t(节能26%),降低原材料消耗1 158 kg/t(降耗27%),减少碳排放236 kg/t(碳减排26%);与复合硅酸盐水泥相比,矿渣硅酸盐水泥可实现节约能源352 MJ/t(节能6%),降低原材料消耗278 kg/t(降耗8%),减少碳排放47 kg/t(碳减排7%)。与不掺加矿粉的普通商品混凝土比较,掺矿粉的商品混凝土可实现节约能源97 MJ/m3(节能5%),降低原材料消耗7 kg/m3(降耗0.3%),减少碳排放12 kg/m3(碳减排5%)。高炉渣资源化生产矿渣硅酸盐水泥和商品混凝土具有明显的环境效益。

Environmental Benefits Assessment of Blast Furnace Slag Recycling for Green Building Materials Based on LCA

Blast furnace(BF) slag from iron smelting process,has great recycling potential for producing green building materials.It can be used as cement or concrete admixture in the form of slag powder which is produced in the processing of water quenching and granulating.The recycling processes of BF slag were focused in this study.Based on life cycle inventory(LCI) analysis and GaBi 4 software,resources consumption and greenhouse gas(GHG) emissions of slag portland cement and commercial concrete production processes using BF slag were analysed in a building materials factory,and then environmental benefits from the recycling of BF slag were assessed in terms of energy saving,reduction of raw material consumption and mitigation of GHG emissions.Compared with ordinary portland cement,slag portland cement can save energy 1 911 MJ/t(decreased by 26%),reduce raw material consumption 1 158 kg/t(decreased by 27%) and mitigate GHG emissions 236 kg/t(decreased by 26%).Meanwhile,those results for slag portland cement were 352 MJ/t(decreased by 6%),278 kg/t(decreased by 8%) and 47 kg/t(decreased by 7%),respectively,in contrast to composite portland cement.Likewise,commercial concrete(with slag powder) can save energy 97 MJ/m3(decreased by 5%),reduce raw material consumption 7 kg/m3(decreased by 0.3%) and mitigate GHG emissions 12 kg/m3(decreased by 5%),compared with common commercial concrete(without slag powder).The results showed that the recycling of BF slag for slag portland cement and commercial concrete have obvious positive environmental benefits.