超细循环流化床粉煤灰对碱式硫酸镁水泥力学性能的影响

针对传统碱式硫酸镁(BMS)水泥制备工艺中硫酸镁需加热溶解及粉煤灰添加后相容性差的问题,采用硫酸、超细循环流化床粉煤灰(UCFA)、氧化镁为原料制备BMS水泥,主要研究了UCFA及其掺量对BMS水泥力学性能的影响。结果表明,BMS水泥的抗压强度随养护时间的延长而提高,随UCFA掺量的增加而降低。掺10%UCFA的BMS水泥抗压强度与不掺UCFA的相近,28 d抗压强度分别达到了79.1、79.5 MPa,且具有优异的早强性能。将UCFA与硫酸反应后加入氧化镁制备BMS水泥,优先酸浸可以对UCFA进行刻蚀,通过增加UCFA表面粗糙度来促进其反应,从而改善水泥性能,并且降低生产成本,而且掺入一定量的UCFA可以增加水泥的密实度,从而提高抗压强度。     

以工业轻烧氧化镁为原料制备高纯氧化镁的实验研究

受生产原料和现有生产工艺技术影响,传统工业氧化镁中的杂质钙含量较高,极大地限制了氧化镁的应用范围。以工业轻烧氧化镁为原料,采用再浆洗涤和高温煅烧的方法,制备得到了高纯氧化镁。研究结果表明:工业轻烧氧化镁经再浆洗涤和煅烧后,可以提高氧化镁的纯度;再浆洗涤温度约为70℃,氢氧化镁滤饼煅烧温度约为1 200℃时,原氧化镁中钙含量下降程度较大,氧化镁的纯度可提高至99%以上;并且对于再浆洗涤和煅烧工序,前者对氧化镁纯度提高的影响更明显。     

水泥中氧化镁含量测定的关键问题

结合相关规范,介绍了水泥中氧化镁含量测定原理,从试样溶液的制备、标准溶液的配制、试样中氧化镁、氧化钙、一氧化锰的测定等方面阐述了水泥中氧化镁含量测定中的关键问题,以期提高检测结果的准确度和稳定性。     

超细干粉灭火剂的研发应用进展

综述了国内外超细干粉灭火剂的研发以及开发应用情况,指出当前消防领域干粉灭火剂总的发展趋势是粒径超细化和配方复合化,超细干粉灭火剂配方正由简单筛分普通干粉灭火剂向采用高聚合度基料与多功能辅料复合以及表面包覆改性等高性能制备方向发展;超细干粉的喷射器材和装置,则是从与干粉灭火剂通用型到超细干粉专用型发展,特别是多灭火剂联用、双气溶胶复合喷射的崭新灭火方式,极大地拓展了超细干粉灭火剂的应用领域。超细干粉灭火剂已经成为一种新型灭火剂体系,显示出广阔的开发应用前景。     

谈原子吸收光谱法测定水泥样品中的氧化镁含量

介绍了水泥氧化镁含量测定的必要性和原子吸收光谱法测定氧化镁含量的工作原理,叙述了相应的样品溶液制备方法和分析步骤,并谈及了仪器分析的特点和局限性。     

高岭土的增白途径及物理化学变化过程

高岭土是一种应用广泛的非金属矿物,对其白度值要求很高。常通过煅烧、超细、除铁等综合方法来提高其白度。详细分析了其煅烧、超细、除铁的物理化学过程,并概述了高岭土的除铁技术现状。     

关于特/超细砂混凝土研究现状及发展前景的思考

为有效缓解河砂资源短缺与基础设施快速发展的矛盾，降低大肆开采对生态环境的影响，将特/超细砂部分或者全部作为细骨料制备特/超细砂混凝土，满足绿色发展要求。由文献调查可知，目前特/超细砂混凝土研究处于快速发展阶段，相关学者通过对其基本力学性能、耐久性以及构件的工作性能等的探究，以期推动特/超细砂混凝土在工程实践中的应用。     

超细矿渣粉对泡沫混凝土制备和性能的影响

利用硅酸盐水泥和超细矿渣粉,采用化学发泡方法制备高性能、低密度的泡沫混凝土.探讨了超细矿渣粉的添加对泡沫混凝土制备和性能的影响.结果表明,当超细矿渣粉用量为水泥质量的20％,水胶比为0.48时,可以制得干密度为300 kg/m3的低密度泡沫混凝土,其导热系数为0.060 W/(m·K),28 d抗压强度达1.04 MPa.     

水性聚氨酯-环氧互穿网络超细水泥复合灌浆材料的制备及性能研究

采用聚醚二元醇(GE-210)、甲苯二异氰酸酯(TDI-80)、二羟甲基丙酸(DMPA)和环氧树脂(E-51)等为主要原料合成了水性聚氨酯-环氧互穿网络聚合物乳液。以该聚合物乳液为主剂加入固化剂、促进剂、超细水泥等制备了三组份水性聚氨酯-环氧互穿网络超细水泥复合灌浆材料,并对其物理性能进行了研究。结果表明:复合灌浆材料的性能与各组份的用量密切相关,聚合物乳液和超细水泥具有协同作用,二者的用量应保持一定的平衡,综合考虑,当聚合物乳液、固化体系和超细水泥的质量比为7.0∶1.0∶1.25时,所制备复合灌浆材料综合性能最佳。     

用碳酸钠熔融-盐酸分解-原子吸收光谱法测水泥中氧化镁

GB176-1996《水泥化学分析方法》中氧化镁的测定(代用法)中22.2原子吸收光谱法中用氢氧化钠熔融-盐酸分解的方法制备溶液,再用原子吸收光谱法测氧化镁。本文经过多次试验,用碳酸钠熔融-盐酸分解制备溶液,原子吸收光谱法测水泥中氧化镁能得到同样的效果。     

插口组合式空心墙体砌块

研制了一种力学性能优良、凝结硬化快、能耗小、成本低、可方便安装水、电、气、通讯等管线的插口组合式空心墙体砌块。介绍了插口组合式空心墙体砌块的结构、原材料组成、配方、生产工艺、产品性能、适用范围及施工、安装方法。空心墙体砌块主体材料是氧化镁、氯化镁,但由于采用了合适的添加剂,克服了一般氯氧镁材料的耐水性差、遇水后质量与强度大幅度下降的缺陷。     

钢渣微粉对混凝土性能的影响初探

针对普遍使用的C30强度等级的流动性混凝土,利用正交试验设计方法,在试验室内研究了钢渣微粉作为混凝土掺合料对混凝土性能的影响,得出了掺钢渣微粉的混凝土最佳配合比。试验结果表明,水胶比是影响混凝土初始坍落度和7d强度的主要因素,钢渣微粉的掺入会使混凝土28d强度普遍提高,减水剂的掺入量存在最佳值,它可直接减少混凝土的坍落度损失,经过优化设计的混凝土配合比（钢渣微粉掺量30%、水胶比0.36、减水剂掺量1.9%）能够符合混凝土各方面性能要求并且具有一定实用价值。     

The accuracy of compressed gas mixtures

A large number of compressed gas mixtures in the parts per million range have been analyzed to establish their accuracy. Cylinders were obtained from commercial suppliers and included mixtures of nitric oxide, carbon monoxide and methane. The mixtures were analyzed with air-monitoring instruments which were calibrated with standard mixtures prepared volumetrically in-house. The method of preparing the standards was verified by comparison with primary standards obtained elsewhere. The accuracy of the volumetric method was estimated to be ±2% of the component and the precision of mixing ±1% of the component.It was concluded that commercial mixtures of carbon monoxide and methane are usually reliable but that this is not the case for nitric oxide mixtures. The method of preparing standard cylinders in the laboratory was found to provide an alternative to commercial cylinders. Thirty-litre quantities of gas at 200 psig can be prepared for immediate use, thus assuring accuracy and eliminating possible stability problems encountered with long storage periods.     

新型混凝土的应用

论述了高性能混凝土、活性微粉混凝土、低强混凝土、轻骨料混凝土、纤维混凝土、自密实混凝土、智能混凝土等新型混凝土的材料组成,以及近年来在工程中的发展与应用情况。     

A method for preparing silica-containing iron(III) oxide adsorbents for arsenic removal

A method for preparing iron(III)-based binary oxide adsorbents in a granulated form for arsenic removal was studied. The key step in the method was the simultaneous generation of hydrous ferric oxide (FeOOH) sol and silica sol in situ in one reactor. This eventually led to the formation of Fe-Si complexes. The addition of silica enhanced the granulated adsorbent strength but reduced the arsenic adsorption capacity. An optimum Si/Fe molar ratio in the balance of adsorbent strength and arsenic adsorption capacity was found to be approximately 0.33. The effects of aging time, drying temperature and process pH on adsorbents were also evaluated in the study. X-ray diffraction analysis confirmed that the iron(III) oxide in the Fe-Si binary oxide adsorbents was amorphous, largely due to the retardation of the iron oxide crystallization by the presence of silicate species. The surface area of the Fe-Si adsorbents and the particle size of Fe-Si complexed suspensions were determined as well. The batch strength testing procedure introduced in this study can provide a simple and quick evaluation of granulate strength in a wet status. Generally, this developed method can prepare granulated Fe-Si binary oxide adsorbents for column adsorption of arsenic from water.     

Influence of the addition of grinding dust to a magnesium phosphate cement matrix

Magnesium phosphate cement materials were prepared by reacting magnesium oxide with water-soluble phosphates such as mono-ammonium dihydrogen phosphate (ADP), which solidified at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0–40% weight) of grinding dust, waste generated in the clutch disc finishing process by grinding and polishing, were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the cement compositions was verified in terms of setting time, apparent porosity, density and leaching/solubilization tests. The setting time was analyzed according to NM 65 (the Vicat needle) and by indirect calorimetric measurements, the apparent porosity and density of the materials were analyzed by the water immersion method, based on the Archimedes principle. Using an Instron 5500R universal testing machine, various analyses were made to ascertain how the different waste contents in the compositions affected the mechanical strength (axial compression and tensile strength by diametral compression). The results obtained proved highly satisfactory for the application of this waste as an additive in magnesium phosphate mortars. The addition of grinding dust to the magnesium phosphate cement matrix did not affect the formation of new phases or the setting time to any appreciable extent, but an increase in grinding dust content led to an initial increase in strength up to a given limit (about 30% of waste).     

新型混凝土的应用

论述了高性能混凝土、活性微粉混凝土、低强混凝土、轻骨料混凝土、纤维混凝土、自密实混凝土、智能混凝土等新型混凝土的材料组成,以及近年来在工程中的发展与应用情况。     

混凝土构件中氧化镁的危害研究

详细阐述了氧化镁对混凝土构件的损坏机理,通过事故实例分析了混凝土集料中氧化镁的危害性,并提出了防治措施。     

水灰比对外掺氧化镁的介质压蒸膨胀率的影响

为了探索混凝土中外掺氧化镁安定掺量的新方法,开展了水灰比对外掺氧化镁的介质(水泥净浆、砂浆、一级配混凝土、二级配混凝土)压蒸膨胀率影响的试验研究。结果表明:水灰比对外掺氧化镁的介质压蒸膨胀率有重要影响;试体的压蒸膨胀率随着水灰比的增大而减小;压蒸膨胀率随着水泥净浆、一级配混凝土、水泥砂浆、二级配混凝土的顺序依次递减。