共查询到17条相似文献,搜索用时 109 毫秒
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固体消毒剂过氧化尿素湿法合成 总被引:8,自引:0,他引:8
通过考察反应物配比、反应温度、反应时间、稳定剂种类及其用量等因素对湿法制备过氧化尿素实验的影响,确定了过氧化尿素合成的最佳条件为:过氧化氢与尿素的物料配比(摩尔比)1.1:1,反应温度30℃以下,以低温为宜,反应时间50 min,稳定剂水杨酸的加入量为尿素质量的0.5%. 该条件比文献报道的低温反应易实施,且合成过程中过氧化氢损失很少. 针对合成过氧化尿素后母液的回收利用,提出了减压蒸馏实现母液过氧化氢循环的闭路新工艺路线,依据测定的50℃过氧化氢-尿素-水体系相平衡数据所绘相图,对新工艺进行了讨论. 相似文献
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湿法磷酸悬浮净化制取磷酸脲的研究 总被引:1,自引:0,他引:1
对以湿法磷酸和工业尿素为原料合成磷酸脲的工艺进行了研究,探索出了较为适宜的用湿法磷酸悬浮净化法合成磷酸脲的工艺条件和生产工艺流程.通过实验,对合成磷酸脲的主要因素反应温度、反应时间、物料配比、活化剂的用量等工艺条件对产品收率及纯度的影响进行了系统的研究.得出了湿法磷酸直接合成磷酸脲的最佳工艺条件为:反应温度75℃,反应时间0.9 h,反应活化剂RX-Ⅲ用量0.15%(质量分数),尿素与湿法磷酸的物质的量比为1.05:1.为磷酸脲的工业化生产提供了理论依据. 相似文献
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为了回收利用湿法合成过氧化尿素后母液中的H2O2和CO(NH2)2,提出了气体盐析法回收有用物质的方法。采用等温法测定了15℃时CO2-CO(NH2)2-H2O-H2O2四元体系在不同压力下的相平衡数据,结果表明,CO2没有盐析分离效应。实验测定5,10,15℃时C3H8-CO(NH2)2-H2O-H2O2四元体系相平衡数据表明,C3H8具有明显的盐析分离效应,且随着C3H8气体压强的增加,平衡液相中H2O2和CO(NH2)2的质量分数降低。湿法合成过氧化尿素后母液在15℃时加入C3H8气体,可继续使过氧化尿素结晶析出,H2O2的收率可提高26.54%。 相似文献
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以工业级尿素和双氧水为原料,先探讨了不同稳定剂对产品稳定性的影响,选择磷酸二氢钾为稳定剂,再采用正交实验合成过氧化尿素(UP),研究了反应温度、反应时间、原料摩尔比、结晶温度、干燥温度对产品活性氧含量、收率和稳定性的影响.结果表明,合成过氧化尿素的最优工艺条件为:反应温度45℃;反应时间50 min;摩尔比n(双氧水)... 相似文献
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Drew Sinha 《Chemical Engineering Communications》2013,200(7):974-984
Trace metals in hydrogen peroxide and high-purity water, used in wet cleaning of wafers, is correlated to the metallic contamination of the wafer surface since metal contamination adversely impacts IC device yield. Hydrogen peroxide with different level of trace metals, ranging from 100 ppt level to 10 ppb level, is used in the experiment to determine the level of selected metal deposition on the silicon surface. Significant amounts of these trace metallic impurities can be removed by subsequent treatment of the silicon wafer by an acidified solution of water. Contamination of a wafer surface by sodium is also correlated to the level of sodium present in deionized water used in the final rinsing of the wafer. The threshold and mechanism for metal deposition for various metals on wafer surfaces are different. This information is useful in determining purity requirements for process chemicals and improving the wet cleaning process for the next generation of semiconductor devices. 相似文献
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Drew Sinha 《Chemical Engineering Communications》2002,189(7):974-984
Trace metals in hydrogen peroxide and high-purity water, used in wet cleaning of wafers, is correlated to the metallic contamination of the wafer surface since metal contamination adversely impacts IC device yield. Hydrogen peroxide with different level of trace metals, ranging from 100 ppt level to 10 ppb level, is used in the experiment to determine the level of selected metal deposition on the silicon surface. Significant amounts of these trace metallic impurities can be removed by subsequent treatment of the silicon wafer by an acidified solution of water. Contamination of a wafer surface by sodium is also correlated to the level of sodium present in deionized water used in the final rinsing of the wafer. The threshold and mechanism for metal deposition for various metals on wafer surfaces are different. This information is useful in determining purity requirements for process chemicals and improving the wet cleaning process for the next generation of semiconductor devices. 相似文献
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为了改进过氧化尿素合成的生产工艺,采用等温法测定了15℃时NaCl-CO(NH2)2-H2O2-H2O四元体系及其三元子体系CO(NH2)2-H2O2-H2O和NaCl-CO(NH2)2-H2O的相平衡数据,依据所绘相图分析,结合热重和XRD表征,得出实验条件下NaCl和尿素能形成新的加合物CO(NH2)2×NaCl,其热稳定性比纯尿素高. 根据相图计算,15℃时CO(NH2)2-H2O2-H2O体系合成过氧化尿素的适宜条件范围较宽,在母液不利用的情况下H2O2的收率为58.08%;而在NaCl-CO(NH2)2-H2O2-H2O体系中,NaCl对过氧化尿素形成没有盐析效应. 相似文献
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考察在干法和湿法生产工艺中添加不同种类流动性改性剂对脲醛模塑料流动性及外观的影响。结果表明,在干法生产工艺中加入流动性改性剂时,亲水性的比亲油性的效果好;当聚乙二醇(PEG)1000,PEG400复配时,对脲醛模塑料制品的表面影响较小,并且在添加总量为0.5份、PEG1000与PEG400质量比为7:3时,脲醛模塑料流动性增加了20.0%。 相似文献
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In this work, three technologies are studied for the purification of phosphoric acid produced by the wet process: chemical oxidation with hydrogen peroxide, adsorption onto activated carbon, and electrochemical oxidation by boron‐doped diamond anodes. The treatment of wet‐process phosphoric acid by chemical oxidation with H2O2 as oxidizing agent can remove 75 % of the initial TOC as maximum, indicating that this wet‐process phosphoric acid contains an important amount of organics that cannot be oxidized by hydrogen peroxide under the operation conditions used. High temperatures and hydrogen peroxide/TOC ratios close to 150 g H2O2/g TOC allow obtaining the best chemical oxidation results. The adsorption onto activated carbon can remove between 40 and 60 % of the initial TOC as maximum. Adsorption times of 2 hours and activated carbon/WPA ratios close to 12 g AC/Kg WTP assure both steady state and maximum adsorption of organics. The electrochemical process is the only technique by which complete mineralization of WPA organics can be achieved. Operating at 60 mA cm–2 and at room temperature, high current efficiencies are achieved which only seem to decrease by mass transport limitations. 相似文献