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磷石膏制备建筑石膏工艺研究 总被引:2,自引:1,他引:2
化学石膏的资源化利用是保护环境、实现可持续发展的重要课题之一。磷石膏是排放量最大的化学石膏,而磷石膏中的可溶性磷和氟是影响建筑石膏性能的主要因素,采用石灰中和法将磷石膏中的可溶性磷和氟变成难溶于水的稳定物质,消除其对建筑石膏性能的影响,同时对磷石膏的煅烧工艺进行研究,并对显微结构进行了观察。结果表明,加入3%生石灰,中和预处理磷石膏,通过150℃煅烧,陈化4d所得建筑石膏性能稳定,改善了磷石膏结构疏松、空隙率大的缺陷,可达到GB9776—88《建筑石膏》优等品要求。 相似文献
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在不同温度和不同的时间对建筑石膏进行煅烧处理,其中三相成分是不同的,通过分析确定三相组成来分析建筑石膏的性能。研究表明:煅烧温度160℃,煅烧时间2 h时,石膏水化晶体发育完整,生长致密,在凝结时间、标准稠度及强度等方面均表现出优异的性能。 相似文献
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对磷石膏制备的复相石膏煅烧工艺进行了研究。结果表明:保温时间和升温速率对两种石膏的烧成比例影响较大。获得不同半水-无水比例的复相磷石膏体系可以通过控制升温速率和保温时间来实现。复相磷石膏与单相石膏比较,具有较好的早期强度和后期强度。 相似文献
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研究山西青石膏的加热脱水过程,不同粒度、烘烤温度、烘烤时间对脱水产物及其水化性能的影响。研究表明:不同粒度的青石膏有不同的临界脱水温度;不同粒度的青石膏在其临界脱水温度脱水后脱水产物物理性能不同;同一粒度的石膏,保温时间相同,烘烤温度不同或烘烤温度相同,保温时间不同,其脱水产物主要物相和水化性能也不同。 相似文献
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采用生物陶粒滤柱作为预处理工艺,考察了其对滏阳河水的处理效果以及影响因素,并确定了运行参数。试验结果表明:生物滤柱对各种藻的去除效果不同,且去除率随滤速的上升而降低;有机物的去除率受滤速影响不大,但随着温度的上升而提高。生物预处理不但能够降低混凝剂的用量,而且使溶解氧增大,改善了水质。 相似文献
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混凝-超滤去除腐殖酸的试验研究 总被引:24,自引:4,他引:24
进行了直接超滤和混凝-超滤组合工艺对腐殖酸的去除效果和膜污染状况的试验。结果表明,超滤前另混凝土预处理对腐殖酸的DOC和UV254的去除率分别从28%、40%提高到53%、78%。同时高效液相色普(HPLC)分析表明,混凝-超滤组合工艺对分子质量<6000u的有机物的去除率提高幅度更为显著。混凝-超滤组合工艺的最佳pH值条件pH=7,通过卷扫混凝使小分子有机物结合成微絮体,降低了膜孔污染,使超滤保持了较同的渗透通量。 相似文献
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Softening is designed to remove hardness ions, but it can also remove NOM and particles, yielding the possibility to use the process as a pretreatment for ultrafiltration. The objectives of this research were to understand the nature of the fouling mechanisms for ultrafiltration when used for waters that either require softening or have been softened, and to use that understanding to determine promising options for the use of softening as a pretreatment before ultrafiltration. To understand fouling mechanisms in the integrated system with softening and ultrafiltration, three different levels of softening performance in terms of removal of inorganics and organic matter were selected. Experiments were performed with both natural waters and synthetic waters with similar (but separable) inorganic, organic, and particulate characteristics. The synthetic waters were used to distinguish among inorganic fouling by precipitates, organic fouling, particulate fouling, and combined fouling by particles and organic matter. The results showed that organic matter played a major role in fouling, either by itself or by adsorption onto particles, and that softening pretreatment effectively reduced the foulants prior to ultrafiltration. 相似文献
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氟硅树脂石膏防水剂的制备与应用 总被引:1,自引:0,他引:1
以有机氟﹑有机硅以及(甲基)丙烯酸酯为原料,采用溶液聚合的方法制备了氟硅树脂防水剂,探讨了软硬单体配比、反应温度和单体投入方式对防水剂性能的影响,确定了工艺参数。研究了此防水剂对石膏试样耐水性能的影响。试验结果表明:该氟硅树脂石膏防水剂对石膏试样的短期防水性能具有显著改善,但长期使用时,防水性能有一定程度的削弱。 相似文献
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利用生物陶位反应器对水源水生物预处理进行研究.试验研究了该反应器对水源水法度、色度、有机物、氨氮等的去除效果;分析探讨了水头损失变化规律;分析比较了生物预处理与其它处理方法对水源水中总有机物(TOC)的去除.结果表明,生物陶粒反应器是一种有效的生物预处理设备,有着广阔的应用前景. 相似文献
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利用剩余污泥作为接种体,在不添加任何营养元素的情况下,成功启动了两室型微生物燃料电池(MFC)。对剩余污泥进行碱解预处理,考察将其作为MFC底物的可行性,同时分析了剩余污泥经不同时间的碱处理,MFC产电性能的变化及其对污泥的降解效果。结果表明:利用碱预处理污泥作为底物时,MFC的稳定输出电压、最大产电功率密度和对TCOD的去除率均提高,同时周期运行时间延长。并且,随着碱处理时间的延长,MFC的稳定输出电压、产电功率密度和对TCOD的去除率均增大。当碱处理时间为24 h时,稳定输出电压达到630 mV(外阻R=500Ω),最大产电功率密度为11.73 W/m3,对TCOD的去除率为25.3%。这与碱处理使得固体有机物被水解有关。 相似文献
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Ultrafiltration alone can remove only a portion of the effluent organic matter (EfOM) from biologically treated sewage effluent (BTSE). Use of pretreatment not only improves the EfOM removal but also reduces the membrane fouling. In this research, NTR 7410 ultrafiltration membrane was employed to remove EfOM from BTSE. Different pretreatments namely FeCl(3) flocculation and powder activated carbon adsorption were evaluated. The highest removal of organic matter was observed when flocculation followed by adsorption was used as pretreatment. The flocculation and adsorption removed 68.5% and 71.4% of hydrophobic organics, respectively. The molecular weight (MW) of the EfOM in BTSE ranged from 300 to about 400000 Da. After the flocculation pretreatment, the majority of large MW organic matter was removed. The pretreatment of the flocculation followed by adsorption led to very high removal of both small and large organic matter. Further, this pretreatment led to practically no filtration flux decline. 相似文献
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Treatment of landfill leachate by the Fenton process 总被引:28,自引:0,他引:28
In recent years, studies of leachate treatment by conventional Fenton, photo-Fenton and electro-Fenton processes have indicated that these methods can effectively reduce concentrations of organic contaminants and color. In addition, the process can increase the biodegradable fraction of organic constituents in leachate, particularly in mature or biologically recalcitrant leachate. Oxidation and coagulation both play important roles in the removal of organics. Initial pH, dosages of Fenton reagents, aeration, final pH, reagent addition mode, temperature, and UV irradiation may influence final treatment efficiency. In this paper, current knowledge of performance and economics of Fenton processes for treatment of landfill leachate as reported for laboratory, pilot and full-scale studies is reviewed, with the conclusion that the Fenton process is an important and competitive technology for the treatment or pretreatment of landfill leachate. 相似文献