轻质耐水石膏墙体材料的制备与研究

研究了EPS颗粒的掺量对石膏吸水率、表观密度、强度以及耐水性能的影响。结果表明:EPS颗粒的最优掺量为1.3%,此时石膏的表观密度为839.06 kg/m3;在干燥状态下的抗压、抗折强度分别为4.05 MPa和2.06 MPa;吸水率为33.85%;抗压和抗折软化系数分别为0.517和0.650,比未掺入EPS颗粒时分别提高了20.79%和11.49%。     

EPS颗粒与玄武岩纤维对脱硫石膏性能的影响

通过在脱硫石膏中掺入膨胀聚苯乙烯(EPS)颗粒与玄武岩纤维,研究具有轻质与增韧性的脱硫石膏复合材料。结果表明,脱硫石膏中EPS颗粒的最佳掺量为0.9%;当玄武岩纤维掺量为1.6%时,EPS颗粒/脱硫石膏材料在干燥状态下的抗压与抗折强度分别为6.50 MPa和3.98MPa,与未掺纤维相比,强度分别提升35.98%和67.93%。在此条件下获得的EPS颗粒/脱硫石膏试块吸水率为25.81%,表观密度为0.834 g/cm~3,EPS颗粒/脱硫石膏复合材料性能较优。     

化学发泡对石膏基泡沫混凝土性能的影响

采用化学发泡法对石膏进行发泡,制备石膏基泡沫混凝土.结果表明:化学发泡法制备的泡沫混凝土水化产物并没有发生变化,仍为二水石膏.随发泡剂量的增加泡沫混凝土强度下降,孔隙率增大,密度下降,但耐水性未有明显下降.缓凝剂的掺入对凝结时间和强度都有一定影响.纤维量的少量增加,对泡沫混凝土的抗折增大不明显.微观分析显示:未掺发泡剂时生成的二水石膏结构要比掺发泡剂的结构致密.     

磷酸对石膏制品耐水性能的影响研究

以建筑石膏为主要原料,通过吸水率及强度试验以及SEM、XRD分析研究了磷酸对石膏制品耐水性能的影响。结果发现,加入磷酸后石膏制品中形成了不溶于水的磷酸一氢钙固体,覆盖在石膏晶体表面,使石膏制品的吸水率明显降低,抗压和抗折软化系数明显提高。磷酸掺量为0.15%时石膏制品的抗折软化系数为1.05,抗压软化系数为0.89,吸水率仅为4.36%,较普通石膏的耐水性有较大改善。但掺磷酸石膏制品中存在较多空隙,抗压强度降低。复掺水泥后,掺磷酸石膏制品的吸水率增大,但仍小于纯石膏。随着水泥掺量的增大,掺磷酸石膏制品的干抗压强度提高,抗压软化系数呈现先上升后下降趋势。抗压软化系数最大值为1.74,此时水泥掺量为20%。复掺水泥对掺磷酸石膏制品的干抗折强度影响不大,但水泥用量越多,试件的抗折软化系数越低。     

复合硅酸盐水泥改善石膏材料耐水性能研究

以改善石膏耐水性为目的,采用复合硅酸盐水泥作为无机改性剂,研究复合硅酸盐水泥及其掺量对石膏表观密度、强度、吸水率、软化系数的影响。结果表明,适量复合硅酸盐水泥的掺入可以改善石膏的强度、软化系数及吸水率;水泥的最佳掺量应为20%,此时石膏干抗压强度、干抗折强度、湿抗压强度、湿抗折强度、抗压软化系数、抗折软化系数分别为22.82 MPa、6.95 MPa、10.73 MPa、4.22 MPa、0.47、0.61,相较于未掺入分别提高18.85%、14.12%、46.79%、31.06%、23.68%、15.09%。     

泡沫混凝土性能优化初探

主要研究了水胶比、发泡剂稀释倍率、增稠剂种类和掺量、增强纤维种类和掺量等对泡沫混凝土性能的影响,以期找到改善泡沫混凝土性能的措施.研究结果表明:在水胶比为0.3及发泡剂稀释倍率为1∶70条件下,配制干密度为400kg/m3的泡沫混凝土较为适宜,其抗压强度可达0.88MPa;掺入占胶凝材料质量0.1%的纤维素醚或占浆体体积0.1%的玻璃纤维,虽然泡沫混凝土的干密度有所增大,但其吸水率降低,抗压强度明显提高,分别可达1.34MPa和1.48MPa.     

凝灰岩发泡材料的制备及性能影响因素研究

以信阳凝灰岩为主要原料,碳化硅为发泡剂,制备出无机发泡材料。探讨了碳化硅的发泡机理,并对凝灰岩掺量、发泡剂掺量、促进剂掺量、发泡温度、发泡温度下保温时间、成型压力及升温速率等影响凝灰岩发泡材料性能的因素进行了研究。确定了较合适的参数为:凝灰岩掺量50%、发泡剂掺量0.75%、磷酸钠掺量2.5%、硼砂掺量2.5%、发泡温度975℃、发泡温度下保温时间30 min、坯体成型压力4 MPa、升温速率20℃/min。此条件下制得的发泡材料表观密度约为0.54 g/cm3,吸水率为0.54%。     

生石灰对粉煤灰-石膏复合材料的改性研究

生石灰作为粉煤灰活性激发剂掺入粉煤灰-石膏混合体系中,探究其对粉煤灰-石膏复合材料表观密度、强度、吸水率以及软化系数等指标的影响,达到改善石膏不耐水的缺陷和降低生产成本的目的。结果表明：生石灰最优掺量为24%,此时石膏表观密度增加4.3%,吸水率降低15.84%,干抗压强度增加21.78%,湿抗压强度增加34.32%,湿抗折强度增加12.37%,抗压软化系数增加10.50%,抗折软化系数增加62.36%。     

泡沫混凝土性能优化初探

主要研究了水胶比、发泡剂稀释倍率、增稠剂种类和掺量、增强纤维种类和掺量等对泡沫混凝土性能的影响,以期找到改善泡沫混凝土性能的措施．研究结果表明：在水胶比为0．3及发泡剂稀释倍率为1∶70条件下,配制干密度为400 kg/m3的泡沫混凝土较为适宜,其抗压强度可达0．88 M Pa;掺入占胶凝材料质量0．1％的纤维素醚或占浆体体积0．1％的玻璃纤维,虽然泡沫混凝土的干密度有所增大,但其吸水率降低,抗压强度明显提高,分别可达1．34 M Pa和1．48 M Pa ．     

利用铁尾矿制备发泡水泥

为提高铁尾矿的利用率,以普通硅酸盐水泥为基质材料,铁尾矿为掺和料,通过化学发泡法制备发泡水泥。研究了铁尾矿掺量、发泡剂用量、水灰比、硬脂酸钙等因素对发泡水泥抗压强度和密度的影响,并确定最佳原料配比。结果表明,原料最佳配比为:铁尾矿55%,普通硅酸盐水泥45%,发泡剂8%,硬脂酸钙0.35%,聚丙烯纤维0.3%,在水胶比为0.43的条件下,发泡水泥7 d和28 d抗压强度分别为1.35 MPa和1.65 MPa,干密度为698.25 kg/m~3。     

China rare earth market review

正November 1~10,2014Chinese rare earth market was still inactive.Demand for rare earth products was weak.Consumers took a wait-and-see attitude for lower price.As it was an off season for rare earth products,it was expected that prices of rare earth could continue turbulence at the bottom in short terms.Due to a sharp drop,demand for rare earth from downstream recovered.Affected by new energy vehicles,wind powder and energy-efficient appliances,production of rare earth permanent     

China rare earth market review

正August 1~10,2014 There was some good news in rare earth industry recently.Restructuring plans of rare earth groups led by Baotou IronSteel Group and Xiamen Tungsten Group respectively have been approved by MIIT.And rare earth storage policy,which had been expected for a very long time,has been launched officially.Pushed by the good news,rare earth price started to rebound since August 5.Price of didymium oxide and dysprosium oxide rose about 1% to 2%,averagely.About 10% of     

China rare earth market review

正July 1~10,2014Due to weak demand from downstream industry and slow transactions,rare earth market remained weak and price of rare earth products continued to decline.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,     

New energy vehicle:an opportunity for rare earth magnets

<正>Extracted from Securities Guide 1.Popularity of new energy vehicles—an irresistible market trend1.1 Progress of new energy vehicles Chinese Premier Li Keqiang said recently on a visit to Xi'an BYD Autos that new energy vehicles,especially new energy bus,can lessen environment and noise pollution.He encouraged the use of new     

注浆加固技术在十三矿-685 m进风大巷中的应用

针对煤矿开采深度不断向深部延伸，掘进巷道受深部高应力的影响越来越大，巷道围岩整体稳定性差，矿山压力显现越剧烈现象，一般锚网喷加锚索支护无法从根本上控制巷道的变形。总结了平煤股份十三矿-685 m进风大巷注浆加固技术，依据对巷道掘进之后变形监测数据的采集，对巷道变形机理进行分析研究，并对注浆时段进行了合理选择，在对巷道的注浆工艺进行了充分论证的基础上，对巷道进行了注浆。注浆后效果表明:巷道滞后注浆时间段的选择非常重要，巷道在恰当的时间内进行注浆加固施工，能有效控制巷道的变形，巷道注浆后变形量明显减小，岩体的稳定性明显增强，减少了巷道日常维修工作，降低了矿井的生产成本，保障了矿井的安全生产。     

Brief news

正China Minmetals Rare Earth Construction of Jianghua Separation Plant is set to complete at the yearend Civil works of Jianghua Separation Plant have been finished and the company is installing and debugging equipments now.It is estimated that construction of Jianghua Separation Plant will be     

Brief news

正Total transactions of rare earth in Rare Earth Ex-change Center of Hunan South Rare and Precious Metal Exchange neared 40 billion yuan from January to October From the opening in January of this year to the end of October,the total transaction of rare earth products in Rare Earth Exchange Center of Hunan South Rare and Precious Metal Exchange neared40 billion yuan.There are 16 varieties including dysprosium oxide and terbium oxide traded on the exchange center,one of the largest trading platforms for rare earth oxides in China.     

Theoretical basis for optimal collector concentrations and pulp pH values during flotation of sulfide-free minerals

A hypothesis that associates optimal conditions of mineral flotation with a zero charge of their surface is put forward. This hypothesis serves as a basis for a methodology to obtain and verify quantitative physical-chemical models for a minimal necessary concentration of a collector during flotation of sulfide-free minerals. These models may be of use for upgrading engineering processes of flotation and as a job for the concentration plant automation systems. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 89–99, March–April, 2006.     

基于LPWAN技术的采煤沉陷区杆塔倾斜监测系统

随着地下采煤活动不断加大，越来越多的输电杆塔不可避免地被建设在煤矿沉陷区。目前，现有手段采用靠人力去进行定期检查一定会浪费大量的人力和物力，因而需开展对位于煤矿沉陷区的杆塔进行实时在线检测。基于NB-IoT和LoRa提出了一种新的算法——低功耗广域网（LPWAN）技术，提出了一种新型的输电杆塔倾斜监测系统，其中包含1个主节点和多个子节点，以适应地域广和远距离的需求信息监控。该系统通过LoRa多节点网络的数据传输，将杆塔的倾斜参数通过NB-IoT上传至在线实时监控系统。管理人员可以从后台得出监测数据并分析结果，及时对处于煤矿沉陷区的有故障的输电杆塔进行针对性的维护。     

基于AutoCAD的复杂曲线绘制的实现

介绍了如何利用其他软件在AutoCAD中精确绘制各种不同规划曲线的技巧 ,很好地解决了在AutoCAD中绘制多义线方法形成复杂曲线的误差问题 ,取得了较好的效果 ,具有实际意义。