- 1. 北京科技大学
- 2. 北京市海淀区学院路30号北京科技大学
摘要: 基于磷渣材料水化特性和矿山充填应用条件，研究碱激发水泥-磷渣共同作为胶凝材料（CPCM）胶结含硫尾砂的可行性。选取生石灰、NaOH、Na2SiO3作为激发剂，开展CPCM固化性能试验，并评价CPCM与含硫尾砂相容性。研究结果表明：磷渣掺量为水泥的100%，生石灰为3%时，CPCM终凝时间300 min，28 d抗压强度40.6 MPa，基本可等量替代P.O 42.5水泥应用于矿山嗣后充填。Na2SiO3掺量4%时，CPCM终凝时间比水泥缩短39.3%，7 d强度提高31.1%。与水泥相比，CPCM使充填体凝结时间缩短8 h左右，且固化28 d后强度未出现劣化，表明CPCM与含硫尾砂相容性好。XRD、SEM和EDS分析表明，CPCM水化产物主要为Ca(OH)2和C-S-H。磷渣不断水化，导致Ca(OH)2含量下降，逐渐形成致密的低Ca/Si比C-S-H，这不仅保证了CPCM后期强度增加，而且避免了充填体强度劣化。
Curing performance of alkali activated cement-phosphorous slag and its compatibility with sulfur tailings
Abstract: Phosphorus slag (PS) is an industrial waste discharged during the process of refining yellow phosphorus by a high-temperature electric furnace. PS is generally deposited on the surface in situ, which takes up a lot of land and brings environmental pollution problems. The content of glass phase in electric furnace PS is more than 90%, indicating that it has potential cementitious property. As cement admixture, PS can cause cement retarding, and the applicant has less enthusiasm on it. Based on the hydration characteristics of PS and the application of mine filling, the feasibility of alkali-activated cement-PS used as cementitious material (CPCM) to cement sulfur tailings was studied. The quicklime, NaOH, and Na2SiO3 were selected as the activators to carry out the CPCM curing performance test in laboratory, and the compatibility of CPCM with sulfur tailing was evaluated. The results showed that when the ratio of PS to cement was 1:1, quicklime was 3% of PS, the final setting time of CPCM was 300 min, and its strength for 28 days was 40.6 MPa, which can basically replace P.O 42.5 cement in the subsequent filling process. When the Na2SiO3 was 4% of PS, the final setting time of CPCM was 39.3% shorter than that of cement, and the strength for 7 days increased by 31.1%. Compared with cement, the setting time of backfill was shortened by 8 hours by CPCM, and its strength did not show deterioration after curing for 28 days. Therefore, the CPCM was very suitable for cementing sulfur tailings. XRD, SEM and EDS analysis showed that the CPCM hydration products were mainly Ca(OH)2 and C-S-H, and the PS hydration resulted in the decrease of Ca(OH)2, and forming a compact low Ca/Si ratio C-S-H. It not only improved the later strength of CPCM, but also avoided the strength deterioration of backfill.