Experimental study on thermal and mechanical properties of tailings-based cemented paste backfill with CaCl_(2)·6H_(2)O/expanded vermiculite shape stabilized phase change materials

CaCl_(2)·6H_(2)O/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 CaCl_(2)·6H_(2)O 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℃.This work can provide theoretical basis for the utilization of heat storage backfill in green mines.

阻燃秸秆/膨胀蛭石复合防火门芯材性能研究

为弥补传统防火门芯材在自重和环保等方面的不足,以阻燃秸秆、膨胀蛭石和耐火水泥等为原料,制备阻燃秸秆/膨胀蛭石复合防火门芯材料。对玉米秸秆进行阻燃处理并评价阻燃效果,然后制备防火门芯材试件,并对芯材性能进行测试。试验结果表明:以Na_(3)PO_(4)与CaCl_(2)反应生成的Ca_(3)(PO_(4))_(2)能够提高秸秆的初始热分解温度和残炭量;通过测试试件性能发现,发泡剂掺量和水灰比对试件抗压强度影响较大,阻燃秸秆和发泡剂掺量对试件导热系数影响较大;当膨胀蛭石掺量为10%,水灰比为0.55,30%双氧水掺量为5.0%,阻燃秸秆使用量为0.5%时,试件性能最佳,其抗压强度>0.4 MPa,导热系数<0.12 W·mK^(-1),在不燃性试验和热值测试中均符合相关规范要求。

蛭石配制低密度水泥浆实验研究

为了克服常规低密度水泥浆强度低和漂珠低密度水泥浆在高压下密度上升的缺点 ,通过室内实验研究 ,根据粒度级配原理 ,以蛭石为主要减轻材料、辅以其它硅质材料 ,开发出密度 1.35～ 1.5 0 g/cm3 的低密度水泥浆体系。室内实验研究表明 :该水泥浆体系流变性能、滤失性能良好 ,且有一定的膨胀性能 ,适于低压易漏地层固井。通过扫描电镜和X衍射等方法 ,研究了蛭石对水泥水化结晶的影响 ,分析了其作用机理。

高包容量放射性焚烧灰水泥固化材料的研制

为实现核废物处置成本最小化,提高放射性焚烧灰的固化效率和水泥固化体的安全性,开展了高包容量放射性焚烧灰水泥固化材料的研究。结果表明:经偏高岭土、粉煤灰、沸石、蛭石及聚合物乳胶粉优化改性的新型水泥固化材料,固化体中的放射性焚烧灰包容量高(40%),力学性能及耐久性能优良,核素离子浸出率低,尤其是固化超铀核素时,第42d浸出率<1.0×10–6cm/d,累计浸出分数<6.0×10–4cm。新型水泥固化材料可大幅度减小单位数量核废物的最终固化体积。

研究不同阻燃剂对氯氧镁水泥EPS板性能的影响

本文采用硼酸锌、蛭石、氢氧化铝等不同的阻燃并与氯氧镁水泥进行协效,并将其加入到聚苯乙烯(EPS)板中,研究它们之间的相互作用。结果表明:实验的各个组合均提升了聚苯乙烯泡沫板的LOI值,其中硼酸锌、蛭石的加入,使其LOI值提升至33.3%、32.4%,而氢氧化铝阻燃剂的加入可使其LOI值提高至33.7%。此外,通过正交实验得出,当复合阻燃体系中氢氧化铝/硼酸锌/蛭石为14%/6%/8%时,浸渍后制得的聚苯乙烯泡沫保温板的密度为0.06042g/cm3,导热系数为0.03659W/(m·K),抗拉强度为0.0592MPa,LOI值为34.8%,阻燃效果显著。

高层建筑水泥灰-膨胀蛭石混合料保温隔热屋面施工技术分析

以江苏南通某高层建筑水泥灰-膨胀蛭石混合料保温屋面工程施工为例,从节能材料资源化再利用的角度介绍一种新型复合保温屋面设计与施工方法。该方法主要以垃圾焚烧灰资源化利用为技术导向,将垃圾焚烧灰作为半胶凝活性掺合料应用于屋面保温构造。屋面保温构造设计主要依靠双重保温隔热构造措施;一是由水泥、石灰、垃圾焚烧灰、膨胀蛭石和水按照一定比例配制而成的水泥灰-膨胀蛭石混合料;二是纤维增强硅酸钙板。文章重点介绍了水泥灰-膨胀蛭石混合料的配合比设计和保温屋面施工工艺,可为垃圾焚烧灰资源化工程应用提供一定的理论借鉴。

水泥膨胀蛭石保温隔热制品性能影响因素研究

研究了影响水泥膨胀蛭石保温隔热热制品性能的关键因素。研究结果表明,膨胀蛭石的颗粒级配控制在1.18～4.75mm,其中1.18～2.36mm颗粒约占60%左右;水泥与膨胀蛭石的体积比为1∶6;水灰比为2.2;在压缩率为30%～35%的条件下成型;通过温度25±5℃,湿度60%～70%自然养护28d的制品具有良好的技术性能。