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磷酸镁水泥的研究与工程应用 总被引:4,自引:0,他引:4
分析阐明了磷酸镁水泥(MPC)的凝结硬化作用机理,指出MPC是在酸性条件下通过化学反应形成以磷酸镁为主要黏结相的水泥质陶瓷材料,并对MPC凝结时间的控制技术进行了探讨;概述了MPC材料的性能特点,并对其处理固体废物进行了试验研究;同时结合MPC的性能特点,对其工程应用做了简单介绍。 相似文献
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化学结合磷酸镁水泥(MPC)是一种快硬、早强的新型胶凝材料,可用于混凝土结构的快速修补.通过三种不同细度1 700℃重烧氧化镁(M)和工业级KH2P04(P)制备钾基磷酸镁水泥,研究M/P摩尔比、MgO细度、硼砂掺量等因素对磷酸镁水泥凝结时间和力学性能的影响,以XRD和TG-DSC表征磷酸镁水泥的水化产物.实验结果表明,磷酸镁水泥最佳M/P在4~5之间,1d强度最高可达45.6 MPa; MgO粉末细度对磷酸镁水泥的凝结性能影响很大,MgO的细度应控制在2 000 ~3 000 cm2/g之间,符合该细度要求的M2具有最合适的凝结时间和最高的抗压强度;硼砂对磷酸镁水泥有一定缓凝作用,但对磷酸镁水泥早期强度影响很大,24 h后抗压强度几乎无差别.磷酸镁水泥的主要水化产物为MgKPO4·6H2O和水化凝胶,但在凝结较快的M3中有MgKPO4·H2O生成. 相似文献
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磷酸镁水泥(magnesium phosphate cement,MPC)是一种新型气硬性胶凝材料,在其中掺入矿物掺合料可改善其性能.本文采用高纯度死烧MgO、磷酸二氢铵及硼砂配制了磷酸镁水泥,掺人一定量粉煤灰或矿粉,研究了这两种矿物掺合料对磷酸镁水泥凝结时间、力学性能及耐水性能的影响.结果表明:随着粉煤灰和矿粉掺量的增加,MPC凝结时间缩短;砂浆试件抗压强度呈先升高后降低趋势,当掺量为10%时,抗压强度最高,同等掺量的矿粉对MPC早期和后期强度的贡献均优于粉煤灰的贡献;粉煤灰的掺入提高了MPC的耐水性,而矿粉的掺入却有降低MPC的耐水性的趋势;XRD测试表明,不掺掺合料、掺粉煤灰、掺矿粉的MPC的主要反应产物均为MgNH4 PO4·6H2O和一些非晶相,掺矿粉的MPC试件浸水28 d后,表面浸出物主要为MgNH4 PO4·6H2O. 相似文献
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磷酸盐胶凝材料力学性能好,制备工艺简单,为资源化利用铜渣提供了新的途径。本文以铜渣和磷酸二氢钠(NaH2PO4)为原料制备了磷酸盐胶凝材料,采用电子万能试验机、X射线粉末衍射仪及扫描电子显微镜研究了原料配合比和养护条件对铜渣基磷酸盐胶凝材料抗压强度、物相和微观形貌的影响,并采用同步热分析仪考察了磷酸盐胶凝材料的热稳定性。结果表明,原料配合比对磷酸盐胶凝材料的力学性能和微观结构有重要影响,适当提高养护温度有利于强度发展。当NaH2PO4/铜渣质量比为0.30、水/(NaH2PO4+铜渣)质量比为0.15、60℃下养护7 d时,铜渣基磷酸盐胶凝材料抗压强度高达54.70 MPa。铜渣基磷酸盐胶凝材料优异的力学性能源自铜渣中铁橄榄石(Fe2SiO4)与NaH2PO4反应生成的致密无定形结构相。铜渣基磷酸盐胶凝材料热稳定性较好,空气气氛下467℃开始被氧化分解,无定形结构相发生... 相似文献
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磷酸镁水泥(MPC)是以重烧氧化镁、磷酸二氢钾为主要原料,掺入一定量的粉煤灰作为掺合料,硼砂与磷酸氢二钾作为缓凝组分制备而成.本文对低温(-10±2)℃条件下,磷酸镁水泥的力学性能与收缩率进行了测试、使用MIP、SEM等测试手段对磷酸镁水泥低温下性能进行了研究;分析了低温对MPC材料影响的机理.结果表明,一定量的粉煤灰掺入,可以提高低温养护下MPC材料的性能. 相似文献
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以特级矾土细粉为主要原料、铝酸盐水泥为结合剂、六偏磷酸钠为减水剂,磷酸盐选择磷酸二氢铝,采用浇注成型的方法制备高铝质磷酸盐陶瓷,考察了保温时间、煅烧温度和磷酸二氢铝添加量对高铝质磷酸盐陶瓷性能的影响。研究结果表明:添加磷酸二氢铝可以提高高铝质磷酸盐陶瓷的性能,磷酸二氢铝用量为6%(质量分数)时,制备的高铝质磷酸盐陶瓷的抗弯强度达到24.15 MPa;磷酸二氢铝用量超过6%后,对高铝质磷酸盐陶瓷的抗弯强度不利;添加6%磷酸二氢铝,形成的主要物相有石英、刚玉、磷酸盐、硅线石和莫来石,说明添加磷酸二氢铝有利于陶瓷新相的形成。高铝质磷酸盐陶瓷适宜的制备工艺条件:矾土粉用量为96%(质量分数),铝酸盐水泥用量为4%(质量分数),减水剂用量为外加0.1%(质量分数),磷酸二氢铝用量为外加6%(质量分数),保温时间为4 h,煅烧温度为1 250 ℃ 相似文献
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按照GB/T 16801-1997中的方法对十二烷基磷酸单酯的抗静电性能进行研究,考察了十二烷基磷酸单酯钾盐、钠盐、三乙醇胺盐以及未中和的磷酸单酯对聚酯布的抗静电性能,结果表明:钾盐和未中和的磷酸单酯对聚酯布的抗静电效果较好。在确定了使用钾盐和未中和的磷酸单酯作为抗静电剂的条件下,考察了它们的质量浓度对聚酯布抗静电性能的影响,结果表明:当单酯钾盐的质量浓度为4 g/L,单酯为6 g/L时,对聚酯布的抗静电性能较好。在单酯钾盐的质量浓度为4 g/L,单酯为6 g/L时,考察了它们对聚酯布、棉布和腈纶布的抗静电效果,结果表明:它们对腈纶布的抗静电效果都好于其他2种布。在考察了十二烷基磷酸单酯的抗静电性能后,对其抗静电机理进行了探讨。 相似文献
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S. Steven Hotta 《Lipids》1982,17(10):682-685
The biosyntheses of cholesterol from acetate and mevalonate were determined in rat liver homogenates that were prepared and
incubated in buffers containing varying concentrations of phosphate. Relatively little acetate or mevalonate was incorporated
into cholesterol in the absence of added phosphate. When phosphate was added, there was an increase in incorporation of both
substrates. The addition of phosphate resulted in an increase in the incorporation of mevalonate to a maximum, whereas phosphate
appeared to increase the incorporation of acetate at low phosphate levels and decrease the incorporation at higher phosphate
levels. The results appear to be consistent with the possibility that, at low phosphate levels, the biosynthesis of cholesterol
is limited by some phosphaterequiring reaction(s) in the pathway after mevalonate, and at higher phosphate levels, the biosynthesis
is limited by the 3-hydroxy-3-methylglutaryl coenzyme A reductase-catalyzed step. 相似文献
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提出了一种将铝离子引入磷酸锌结构的方法。使用正交试验分析及粒径分布分析,优选出最优的反应条件参数,获得收率为 95.3%、中值粒径 d(0.5)为 1.529 μm的磷酸锌铝;使用硅烷偶联剂改性的磷酸锌铝颗粒微细、大小均匀。将改性磷酸锌铝制成水性环氧底漆与水性丙烯酸防锈漆
并进行耐盐雾及贮存性测试,结果表明:改性磷酸锌铝比磷酸锌表现出更好的抑泡性能与防锈性能;探讨了磷酸锌铝的防锈机理,推测磷酸锌铝与金属基材表面形成了电化学抑制 -物理隔绝的综合防腐蚀体系。获得的磷酸锌铝产物在水性防锈涂料中具备较好的使用前景。 相似文献
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Carlos Garbisu David O. Hall Juan L. Serra 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1993,57(2):181-189
Free-living and polyvinyl foam-immobilized cells of Phormidium laminosum were studied for their phosphate uptake characteristics. Initial phosphate uptake rates yielded hyperbolic curves when plotted against the external phosphate concentration, indicating the existence of a saturatable transport system. The phosphate uptake rates of N-starved free-living cyano-bacteria were also examined and showed that N-starvation led to lower uptake rates. The addition of nitrate to N-starved cyanobacteria markedly increased phosphate uptake. Phosphate uptake by free and immobilized cyanobacteria was inhibited in the dark and stimulated by the presence of calcium ions or bicarbonate. No phosphate uptake was observed when a chelating agent, such as ethylenediaminetetraacetic acid (EDTA), was added to the cultures. Several bioreactors were established for initial studies in using immobilized cyanobacteria for the removal of phosphate from water. Three different types of batch fluidized-bed, as well as two continuous-flow bioreactors (i.e. fluidized- and packed-bed), were examined. Although cyanobacteria immobilized on the polymer foams did not show high phosphate uptake efficiencies, simultaneous removal of nitrate and phosphate from water by means of N-starved immobilized cyano-bacteria appeared to be a promising possibility for future development. 相似文献
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研究了云南昆阳和贵州开阳两种磷矿的反应活性和抗阻缓性,SPSS数学软件回归分析结果表明:磷矿分解率与混酸中硫酸的质量分数之间有良好的线性关系,昆阳磷矿抗阻缓系数为7.104,开阳磷矿抗阻缓系数为7.001,昆阳磷矿的反应活性较开阳磷矿高. 相似文献
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Bentonite combined with sawdust and other metallic compounds was used to remove phosphate from aqueous solutions in this study. The adsorption characteristics of phosphate on the modified bentonite were investigated, including the effects of temperature, adsorbent dosage, initial concentration of phosphate and pH on removal of phosphate by conducting a series of batch adsorption experiments. The results showed that 98% removal rate of phosphate was obtained since sawdust and bentonite used in this investigation were abundantly and locally available. It is concluded that modified bentonite is a relatively efficient, low cost and easily available adsorbent for the removal of phosphate from aqueous solutions. 相似文献