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Xiaoyan Zhang, Tianrun Cao, Lang Liu, Baoyun Bu, Yaping Ke, and Qiangqiang Du, Experimental study on thermal and mechanical properties of tailings-based cemented paste backfill with CaCl2·6H2O/expanded vermiculite shape stabilized phase change materials, Int. J. Miner. Metall. Mater., 30(2023), No. 2, pp.250-259. https://dx.doi.org/10.1007/s12613-022-2503-7
Xiaoyan Zhang, Tianrun Cao, Lang Liu, Baoyun Bu, Yaping Ke, and Qiangqiang Du, Experimental study on thermal and mechanical properties of tailings-based cemented paste backfill with CaCl2·6H2O/expanded vermiculite shape stabilized phase change materials, Int. J. Miner. Metall. Mater., 30(2023), No. 2, pp.250-259. https://dx.doi.org/10.1007/s12613-022-2503-7
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添加CaCl2·6H2O/膨胀蛭石定形相变材料的尾砂基充填体热学与力学性能试验研究

摘要: 采用常压浸渍法制备了CaCl2·6H2O/膨胀蛭石定形相变材料(CEV),以金矿尾砂为充填材料骨料,制备添加CEV的充填体,对不同灰砂比和不同CEV添加比例下充填体的比热容、导热系数和单轴抗压强度(UCS)进行试验测试,分析了上述变量对充填体热学、力学性能的影响。结果表明:膨胀蛭石对CaCl2·6H2O的最大封装能力约为60%,CEV的熔化焓和凝固焓分别高达98.87 J/g和97.56 J/g。对于未添加CEV的充填体,比热容、导热系数和单轴抗压强度均随着灰砂比的降低而降低,对于添加CEV的充填体,比热容随CEV添加比例的增加显著提高,添加12% CEV后,其显热和潜热蓄热能力至少分别提高了10.74%和218.97%。然而CEV的添加会导致充填体孔隙增加,导热系数和单轴抗压强度均随CEV添加比例的增加而降低。当灰砂比为1:8,CEV添加比例分别为6%、9%、12%时,养护期为28天的充填体单轴抗压强度均小于1 MPa。综合考虑充填体蓄热能力和材料成本,推荐充填材料配比方案为灰砂比1:6、添加12% CEV,且添加CEV充填体的蓄热/释热温度区间推荐为20–40°C。本研究可为绿色矿山蓄热充填技术的应用提供理论依据。

 

Experimental study on thermal and mechanical properties of tailings-based cemented paste backfill with CaCl2·6H2O/expanded vermiculite shape stabilized phase change materials

Abstract: CaCl2·6H2O/expanded vermiculite shape stabilized phase change materials (CEV) was prepared by atmospheric impregnation method. Using gold mine tailings as aggregate of cemented paste backfill (CPB) material, the CPB with CEV added was prepared, and the specific heat capacity, thermal conductivity, and uniaxial compressive strength (UCS) of CPB with different cement−tailing ratios and CEV addition ratios were tested, the influence of the above variables on the thermal and mechanical properties of CPB was analyzed. The results show that the maximum encapsulation capacity of expanded vermiculite for CaCl2·6H2O is about 60%, and the melting and solidification enthalpies of CEV can reach 98.87 J/g and 97.56 J/g, respectively. For the CPB without CEV, the specific heat capacity, thermal conductivity, and UCS decrease with the decrease of cement−tailing ratio. For the CPB with CEV added, with the increase of CEV addition ratio, the specific heat capacity increases significantly, and the sensible heat storage capacity and latent heat storage capacity can be increased by at least 10.74% and 218.97% respectively after adding 12% CEV. However, the addition of CEV leads to the increase of pores, and the thermal conductivity and UCS both decrease with the increase of CEV addition. When cement–tailing ratio is 1:8 and 6%, 9%, and 12% of CEV are added, the 28-days UCS of CPB is less than 1 MPa. Considering the heat storage capacity and cost price of backfill, the recommended proportion scheme of CPB material presents cement−tailing ratio of 1:6 and 12% CEV, and the most recommended heat storage/release temperature cycle range of CPB with added CEV is from 20 to 40°C. This work can provide theoretical basis for the utilization of heat storage backfill in green mines.

 

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