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一水氯化镁热分解进程中的理论化学研究 总被引:7,自引:1,他引:6
采用MP3方法研究了一水氯化镁在加热过程中的脱水及水解机理,研究发现,一水氯化镁脱水生长无水氯化镁和水解生成碱式氯化镁是两条竞争的反应路线,而一水氯化镁水解生成氧化镁及碱式氯化镁水解生成无水氧化镁则需较高的活化能,只能在较高温下才能实现,另一方面,无水氧化镁在氯化氢气氛下很容易反应生成碱式氯化镁及一水氧化镁,研究结果对无水氯化镁及无水氧化镁的工业生产具有指导意义。 相似文献
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碱式氯化镁烧结法制备氧化镁晶须的工艺研究 总被引:1,自引:0,他引:1
以氯化镁和氢氧化钠为原料,通过前驱体烧结法制备氧化镁晶须.首先以氯化镁和氢氧化钠为原料合成了前驱体碱式氯化镁晶须,接着将碱式氯化镁焙烧成氧化镁晶须.探讨了各个工艺条件对产物的影响,探索出最佳的工艺条件:氯化镁溶液的浓度为3 mol/L,氯化镁和氢氧化钠的摩尔比为5:1,陈化时间72 h,陈化温度50℃.在此条件下制得了前驱物碱式氯化镁晶须,将碱式氯化镁晶须焙烧,控制升温速率在5℃/min,采取分段升温方式升温至900℃,灼烧时间6 h,即可制得氧化镁晶须.所得的氧化镁晶须表面光滑,直径分布均匀,结晶良好,产率达80%以上. 相似文献
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卤水-氨法碱式氯化镁晶须的制备及影响因素的研究 总被引:1,自引:0,他引:1
在常压下用液相反应法制备了碱式氯化镁晶须,研究了氯化镁浓度、氯化镁与氨水的摩尔比、反应温度、陈化温度、陈化时间对碱式氯化镁晶须制备的影响.根据XRD和SEM测试结果,提出了制备碱式氯化镁晶须的最佳工艺条件:(1)氯化镁浓度为3mol/l;(2)氯化镁与氨水的摩尔比为4:1~6:1;(3)最佳反应温度为30℃;(4)氨水的加料速度为10ml/min~20ml/min;(5)最佳陈化温度为50℃~60℃,最佳陈化时间为48h~72h.制备得到了长径比≥100碱式氯化镁晶须. 相似文献
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卤水——氨法碱式氯化镁晶须的制备及影响因素的研究 总被引:1,自引:0,他引:1
在常压下用液相反应法制备了碱式氯化镁晶须,研究了氯化镁浓度、氯化镁与氨水的摩尔比、反应温度、陈化温度、陈化时间对碱式氯化镁晶须制备的影响。根据XRD和SEM测试结果,提出了制备碱式氯化镁晶须的最佳工艺条件:(1)氯化镁浓度为3mol/l;(2)氯化镁与氨水的摩尔比为4:1~6:1;(3)最佳反应温度为30℃;(4)氨水的加料速度为10ml/min~20ml/min;(5)最佳陈化温度为50℃~60℃,最佳陈化时间为48h~72h。制备得到了长径比≥100碱式氯化镁晶须。 相似文献
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乙二醇氨法制备高纯无水氯化镁工艺研究 总被引:5,自引:0,他引:5
无水氯化镁是电解金属镁的原料也是众多催化剂和医药的中间体.研究以水合氯化镁与高沸点溶剂共沸蒸馏为基础,通过一系列过程制备出含纯99%以上无水氯化镁.过程包括:(1)配置水合氯化镁的醇溶液,(2)采用常压或负压蒸馏脱水,(3)采用不同方法对无水氯化镁醇溶液氨化,再经真空过滤、氨饱和甲醇洗涤,得到六氨氯化镁结晶,(4)经120℃烘干,蒸掉结晶中的甲醇得到六氨氯化镁,(5)经450℃煅烧得到无水氯化镁.通过对全流程的工艺条件的探索,探明了过程控制因素和影响规律.用XRD对六氨氯化镁的分析表明,氨化过程在氨浓度较低情况下,有副反应MgCl2 glycol 2NH3→Mg-glycol 2NH4 Cl ↓发生,NH4Cl夹带在六氨氯化镁中,而镁的醇盐则是无水氯化镁中MgO的主要来源,在较低温度和氨高度过量的环境中该反应可以得到有效抑制. 相似文献
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水氯镁石(六水氯化镁)脱水制无水氯化镁是盐湖镁资源利用的关键环节,复盐法是水氯镁石脱水的重要方法,由复盐合成、造粒及流态化热分解等步骤组成。采用热分析技术(TG-DTG)研究了复盐热解过程。结果显示,复盐热解主要分为两个阶段:第一个阶段脱去六个结晶水;第二个阶段脱去盐酸苯胺助剂,热重结果为后续实验提供理论依据。实验首先通过均匀液滴喷射技术(振动造粒)制备得到六水氯化镁-盐酸苯胺复盐颗粒。然后在流化床中进行复盐热分解脱水、脱助剂得到无水氯化镁。通过实验探索得到水氯镁石复盐流态化热分解的最佳工艺参数:脱水氮气流量1.6 m3/h~1.8 m3/h、脱盐酸苯胺氮气流量1.0 m3/h~1.2m3/h、脱水温度300℃、脱水时间0.5 h、脱盐酸苯胺温度350℃、脱盐酸苯胺时间1 h。 相似文献
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Ilton ES Schaef HT Qafoku O Rosso KM Felmy AR 《Environmental science & technology》2012,46(7):4241-4248
Reactions involving variably hydrated super critical CO(2) (scCO(2)) and a Na saturated dioctahedral smectite (Na-STX-1) were examined by in situ high-pressure X-ray diffraction at 50 °C and 90 bar, conditions that are relevant to long-term geologic storage of CO(2). Both hydration and dehydration reactions were rapid with appreciable reaction occurring in minutes and near steady state occurring within an hour. Hydration occurred stepwise as a function of increasing H(2)O in the system; 1W, 2W-3W, and >3W clay hydration states were stable from ~2-30%, ~31-55 < 64%, and ≥ ~71% H(2)O saturation in scCO(2), respectively. Exposure of sub 1W clay to anhydrous scCO(2) caused interlayer expansion, not contraction as expected for dehydration, suggesting that CO(2) intercalated the interlayer region of the sub 1W clay, which might provide a secondary trapping mechanism for CO(2). In contrast, control experiments using pressurized N(2) and similar initial conditions as in the scCO(2) study, showed little to no change in the d(001) spacing, or hydration states, of the clay. A salient implication for cap rock integrity is that clays can dehydrate when exposed to wet scCO(2). For example, a clay in the ~3W hydration state could collapse by ~3 ? in the c* direction, or ~15%, if exposed to scCO(2) at less than or equal to about 64% H(2)O saturation. 相似文献
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Goldstein S Aschengrau D Diamant Y Rabani J 《Environmental science & technology》2007,41(21):7486-7490
Methanol is used to measure the yield of *OH radicals produced in the photolysis of H2O2 in aqueous solutions. The UV photolysis of H202 generates *OH radicals, which in the presence of methanol, oxygen, and phosphate buffer form formaldehyde, namely, phi(HCHO) = phi(*OH). The quantum yield of *OH has been redetermined in view of literature inconsistencies resulting in phi(*OH) = 1.11 +/- 0.07 in the excitation range of 205-280 nm. The constancy of phi(*OH) and the ease and sensitivity of the formaldehyde product analysis makes the H2O2/CH3OH system suitable for polychromatic UV actinometry. In addition, the relatively low cost of the main components and the possibility of destroying the methanol before disposal qualify the system for both monochromatic and polychromatic actinometry in a large volume of water. The H2O2/CH3OH system was applied in different commercial UV photoreactors. 相似文献
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目的:探究纤维素酶酶法制备稠李花色苷的最佳条件,并研究制备的稠李花色苷对H2O2诱导的大鼠胰岛素瘤(Ins-1)细胞损伤的保护作用。方法:通过单因素试验和正交试验,优化得到酶法制备稠李花色苷的最佳条件;稠李花色苷处理大鼠Ins-1细胞,进行形态学观察、3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐[3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide,MTT]细胞活力实验、2’,7’-二氢二氯荧光素二乙酸酯(2’,7’-dichlorodihydrofluorescein diacetate,DCFH-DA)荧光探针法检测细胞内活性氧实验研究稠李花色苷对H2O2诱导损伤的Ins-1细胞保护作用。结果:纤维素酶法提取稠李花色苷的最佳条件为:温度60 ℃、纤维素酶添加量9 mg/g、料液比1∶35(g/mL)、pH 3.5,此条件下稠李花色苷得率为(0.956±0.027) mg/g;形态学观察及MTT细胞活力实验显示,稠李花色苷对H2O2诱导损伤的Ins-1细胞具有较强的保护作用,DCFH-DA法检测细胞内活性氧实验说明,稠李花色苷能够显著地清除Ins-1细胞内的活性氧。结论:纤维素酶法制备稠李花色苷是一种有效的方法,制备的稠李花色苷对H2O2诱导的大鼠Ins-1细胞损伤具有较强的保护作用。 相似文献
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以无甲醛树脂Arkofix NZF为交联剂,MgCl2·6H2O为催化剂,采用轧-烘-焙工艺,用羟丙基-β-环糊精(HP-β-CD)整理棉织物。研究了HP-β-CD的质量浓度、树脂质量浓度、MgCl2·6H2O质量浓度、pH值、焙烘温度和时间等因素对织物性能的影响,确定最佳接枝工艺为:HP-β-CD质量浓度50g/L,树脂质量浓度60g/L,MgCl2·6H2O质量浓度10g/L,pH值5.5,焙烘温度170℃,焙烘时间3min。结果表明,经HP-β-CD整理的织物折皱回复角和接枝率比经β-CD整理后的高。 相似文献
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To develop a new process for removing high-concentration SO2 from industrial flue gases, the carbothermal reduction of SO2 by oil-sand fluid coke at 700 degrees C was investigated by varying the inlet concentration of either O2 or H2O. Concentrations of O2 and H2O ranged from 0 to 20% and from 0 to 30%, respectively, in a stream of SO2 (18%) with the balance helium. Addition of O2 and H2O was found to enhance SO2 reduction. The enhancement was attributed to the reducing gases, CO and H2, produced by solid-gas reactions between carbon and O2 or H2O. The effects of O2 and H2O on sulfur yield, however, were bifacial: adding O2 and/or H2O increased the sulfur yield when SO2 conversion was incomplete, otherwise, it decreased the sulfur yield through the formation of sulfides such as H2S. The results of a thermodynamic analysis were in a good agreementwith the experimental results, suggesting that gas-solid reactions were slow enough to allow gas-phase equilibrium. This study indicates that carbon, such as oil-sand fluid coke, can be utilized to remove SO2 in flue gases containing O2/H2O and to convert it to elemental sulfur. 相似文献