姜关照, 吴爱祥, 王贻明. 碱激发水泥−磷渣固化性能及与含硫尾砂的相容性[J]. 工程科学学报, 2020, 42(8): 963-971. DOI: 10.13374/j.issn2095-9389.2019.12.19.002
引用本文: 姜关照, 吴爱祥, 王贻明. 碱激发水泥−磷渣固化性能及与含硫尾砂的相容性[J]. 工程科学学报, 2020, 42(8): 963-971. DOI: 10.13374/j.issn2095-9389.2019.12.19.002
JIANG Guan-zhao, WU Ai-xiang, WANG Yi-ming. Curing performance of alkali-activated cement–phosphorous slag and its compatibility with sulfur tailings[J]. Chinese Journal of Engineering, 2020, 42(8): 963-971. DOI: 10.13374/j.issn2095-9389.2019.12.19.002
Citation: JIANG Guan-zhao, WU Ai-xiang, WANG Yi-ming. Curing performance of alkali-activated cement–phosphorous slag and its compatibility with sulfur tailings[J]. Chinese Journal of Engineering, 2020, 42(8): 963-971. DOI: 10.13374/j.issn2095-9389.2019.12.19.002

碱激发水泥−磷渣固化性能及与含硫尾砂的相容性

Curing performance of alkali-activated cement–phosphorous slag and its compatibility with sulfur tailings

  • 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。X射线衍射、扫描电镜和电子能谱分析表明,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摩尔比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。

     

    Abstract: Phosphorus slag (PS) is an industrial waste discharged during the refining of yellow phosphorus by a high-temperature electric furnace. The slag is generally deposited on the surface in situ, and this uses up considerable areas of land and causes environmental pollution problems. The glass phase content in electric furnace PS is over 90%, indicating that the PS has potential cementitious property. As a cement admixture, PS has a retarding effect on cement, thus, its application to cement has become less adopted. Based on the hydration characteristics of PS and the application conditions of mine filling, the feasibility of alkali-activated cement–PS used as cementitious material (CPCM) to cement sulfur tailings was studied. Quicklime, NaOH, and Na2SiO3 were used as the activators to investigate the CPCM curing performance in a laboratory, and the compatibility of CPCM with sulfur tailings was evaluated. The results show that when the PS-to-cement mole ratio is 1∶1, quicklime is 3% of PS, the final setting time of CPCM is 300 min, and the CPCM strength for 28 days is 40.6 MPa, indicating that the material can replace P.O 42.5 cement in the subsequent filling process. When the Na2SiO3 is 4% of PS, the final setting time of CPCM is 39.3% less than that of cement, and its strength for 7 days is 31.1% higher than that of cement. Compared with cement, CPCM shortens the setting time of backfill by 8 hours, and its strength does not deteriorate after curing for 28 days. Therefore, CPCM is suitable for cementing sulfur tailings. X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) analyses show that the CPCM hydration products are mainly Ca(OH)2 and C−S−H. Moreover, the PS hydration resulted in a decrease in the Ca(OH)2 content, and a compact C−S−H gel with a low Ca/Si mole ratio is formed. This not only improves the later strength of CPCM but also prevents the strength deterioration of the backfill.

     

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