利用矿渣-钢渣基胶凝材料(简称冶金渣胶凝材料)代替传统充填料中使用的水泥作为胶结剂,掺入含铅尾砂制成胶结充填料试样,通过流动度和抗压强度表征其工作性能,通过Pb~(2+)浸出质量浓度表征其固化效果,通过X射线衍射、红外光谱、差示扫描量热法等手段分析其物相组成,并与P·I 42.5硅酸盐水泥作对比.在相同条件下,冶金渣胶凝材料试样的流动度平均高出水泥50 mm,且28 d强度符合一般矿山3.0 MPa的要求.冶金渣胶凝材料试样28 d龄期铅浸出质量浓度低于地下水环境质量标准Ⅲ类水0.05 mg·L~(-1)的限值,而水泥为0.1 mg·L~(-1)左右.冶金渣固化铅性能优于水泥的机理在于冶金渣胶凝材料水化生成更多钙矾石.此外,冶金渣胶凝材料水化产物可能存在类沸石相,更有利于吸附固化Pb~(2+).
Backfilling material specimens were prepared with Pb-bearing ore tailings and a blast furnace slag-steel slag based cementing agent( BSCA) used as a replacement for cement in traditional backfilling materials. Other types of specimens with ordinary Portland cement( P·I 42. 5) as cementing agents were also made for comparison. Flowability and compressive strength tests were performed to study the working performance of the specimens,and leaching tests were done to investigate the immobilization of Pb~(2+)in the specimens. The phase composition of the hydrated specimens was analyzed by means of X-ray diffraction,Fourier transform infrared spectroscopy and differential scanning calorimetry. It is found that the backfilling material with BSCA has a flowability of 50 mm higher than that with ordinary cement. The 28-d compressive strength of the BSCA-based specimens reaches 3. 0 MPa,which meets the strength requirement for underground backfilling. The quantities of Pb~(2+)leached from the BSCA-based specimens aged for 28 d are below 0. 05 mg·L~(-1),which is the threshold value of Pb~(2+)concentration for Type Ⅲ ground water in Chinese quality standard for ground water GB / T 14848—93. In comparison,the quantities of Pb~(2+)leached from the cement-containing specimens aged for 28 d are 0. 1 mg·L~(-1). The reason for this higher immobilization degree of Pb~(2+)in the hydrated BSCA-based specimens is that a higher amount of ettringite forms in them. Moreover,the formation of zeolite-like facies in the hydrated BSCA-based specimens is favorable for immobilizing Pb~(2+).