共查询到20条相似文献,搜索用时 15 毫秒
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磷酸铁是合成磷酸铁锂电池正极材料的主要原料,目前多采用硫酸亚铁和磷酸盐共沉淀方法制备。硫酸体系内共沉淀获得的磷酸铁中硫杂质含量较高,目前采用水洗方式脱除,吨磷酸铁洗水用量需60~100吨,硫酸盐废水处理成本高。为从源头削减磷酸铁脱硫过程产生的大量废水,根据硫酸盐高温分解的性质,提出磷酸铁高温煅烧脱硫新方法,开展了热力学可行性计算与高温煅烧脱硫动力学研究。结果表明,磷酸铁中硫元素主要以硫酸根形式存在,高温煅烧可有效促进含硫杂质分解,温度越高,脱硫效果越好。高温煅烧脱硫过程反应动力学级数为2,活化能为88.075 kJ/mol,属于化学反应控制。在温度1173 K、煅烧时间10 min的条件下,磷酸铁中硫杂质含量可降至0.01wt%以下。 相似文献
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A series of Mo/Ni-based hydrotreating catalysts calcined at different temperatures was prepared by impregnation method,and characterized by means of N2 adsorption-desorption,NH3-TPD and TPR techniques.The HDN performance of the catalysts was investigated in a microreactor.The results indicated that with the increase of calcination temperatures,the specific surface area of the catalysts was decreased,the average pore size was gradually increased,and the pore volume change was very small.The acid amount on the surface of the catalysts showed a tendency to ascend firstly, and then to descend with the increase of calcination temperatures, and the acid amount reached the maximum at 500 ℃. The activity of the hydrotreating catalysts was enhanced firstly and then reduced with the increase of calicination temperature,and the optimal calcination temperature was 500 ℃.On the whole,the activity of the catalysts could be improved prepared under suitable calcination temperature,and be suppressed obtained under high calcination temperature. 相似文献
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钛硅沸石TS-1的高温焙烧法再生研究 总被引:2,自引:0,他引:2
研究了负载成“蛋壳型”的钛硅沸石TS- 1催化剂在丙烯环氧化的单管放大试验装置上连续运转 1 2 0 0h失活后的焙烧法再生条件 ,并结合催速失活 ,对该催化剂进行了多次焙烧再生研究。结果表明 ,上述失活催化剂可在氧含量为体积分数6 %的氮气气氛中 ,通过程序升温焙烧于 30 0~ 550℃、2 4h内实现彻底再生 ,使环氧化活性和环氧丙烷选择性完全恢复。经过 5次再生后 ,催化剂活性、选择性与新鲜催化剂相比没有明显差别 ,并在 50 0h的实验室连续评价中活性和选择性保持稳定 相似文献
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焙烧条件对乙苯脱氢催化剂耐水性能影响的研究 总被引:2,自引:0,他引:2
考察了焙烧条件对乙苯脱氢制苯乙烯催化剂耐水性能的影响。提高焙烧温度及延长焙烧时间有利于提高催化剂耐水浸泡能力,减缓水浸泡前后催化剂机械强度下降和磨耗率上升趋势。其原因可能是热处理条件的改变促进了Fe2O3和K2O间的相互作用,形成了大量对水十分稳定的多铁酸钾KFe11O17固熔体,从而提高了催化剂的耐水性,并能与比表面、孔结构、XRD、Mōssbauer谱测定结果较好地关联。 相似文献
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采用共浸渍法制备了m(Fe):m(Mo)=1的Fe-Mo/ZSM-5催化剂,并对其在不同焙烧条件所得样品上NO选择性催化还原反应活性进行了测试。结果表明,焙烧条件对Fe-Mo/ZSM-5催化性能影响明显,600℃焙烧6 h的样品在低温范围具有较好的催化性能,随着焙烧时间或焙烧温度的增加,其NOx转化率依次向高温方向移动,在800℃焙烧后的样品催化活性明显下降。采用XRD和BET对Fe-Mo/ZSM-5样品的体相结构和表面性能进行了研究。结果表明,不同焙烧条件下Fe-Mo/ZSM-5催化剂的晶胞参数和比表面积产生了差别,特别是焙烧温度达到800℃时,其比表面积显著减小,这可能是导致Fe-Mo/ZSM-5催化性能突然下降的主要原因。焙烧过程中残留在的表面含氮物种对Fe-Mo/ZSM-5催化剂上NO选择性催化还原反应活性影响较大。 相似文献
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Donghui Wang Zhengping Hao Daiyun Cheng Xicheng Shi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(7):1246-1251
The effect of calcination temperature on the electronic structure of gold catalyst was investigated in this paper. CO oxidation was employed as a test reaction to correlate the phase changes to the catalytic activity. The TPR, XPS and XRD characterization showed that the highly active Au/FeOx/Al2O3 catalyst contained both gold atoms and ions. The catalytic performance of gold catalyst may depend on the Au0/Au3+ ratio. The best activity in the present work was obtained when the Au0/Au3+ ratio was about 0.89. Copyright © 2006 Society of Chemical Industry 相似文献
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采用共沉淀法制备以Ni为活性组分的Ni-Mg-Al-O高温甲烷化催化剂,考察焙烧温度对催化剂性能的影响。采用N2低温吸附、XRD、H_2-TPR和H_2-化学吸附对催化剂进行表征,并将催化剂用于合成气甲烷化反应。结果表明,焙烧温度高于700℃时,催化剂预还原后织构性能参数变化幅度小。随着焙烧温度的升高,Ni晶粒增大,活性组分与载体之间相互作用增强。焙烧温度700℃时,活性组分分散度最高,催化剂具有优异的低温活性和高温稳定性。 相似文献
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研究了浸渍法制备Mo-Mn/TiO2(MMT)催化剂过程中煅烧温度(300℃、450℃、600℃、750℃)对Mo-Mn/TiO2(MMT)催化剂协同脱硝脱汞活性的影响。结果表明,较低的煅烧温度更有利于MMT催化剂的协同脱硝脱汞性能,同时可有效降低SO2对催化剂活性的抑制作用,最佳煅烧温度为300℃。利用BET、XRD、H2-TPR、FTIR和XPS等表征手段对催化剂的理化性质进行了表征,结果表明较低的煅烧温度有利于提高催化剂中活性成分所占的比例,增加金属氧化物在TiO2载体表面的分散度,提高催化剂的低温还原性能。随着煅烧温度的升高,催化剂的比表面积和孔容均逐渐减小,平均孔径先增大后减小,且在高温下发生烧结;MnO2逐渐向Mn2O3转变,锐钛矿型TiO2逐渐向金红石型转变,同时MoO3由非晶态逐渐向晶态的转化,致使催化剂的协同脱硝脱汞活性下降。 相似文献
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煅烧温度对磁性铁钛复合氧化物微观结构及脱硝活性的影响 总被引:1,自引:0,他引:1
利用共沉淀微波法构筑新型磁性铁钛复合氧化物催化剂,研究了煅烧温度对其物性结构及NH3-SCR脱硝性能的影响,揭示了钛掺杂对磁性γ-Fe2O3晶体高温热转化及其脱硝性能的优化机制。结果表明:当煅烧温度由300℃升至500℃时,磁性铁氧化物的比表面积、孔容先增大后减小,且较高的煅烧温度促使其γ-Fe2O3晶体逐步转变为α-Fe2O3晶体,导致磁性铁氧化物表面Fe2+和活性氧浓度增大,促使其NH3-SCR脱硝性能降低;掺杂钛可提高磁性铁氧化物的热稳定性,抑制了高温煅烧下γ-Fe2O3晶体向α-Fe2O3晶体的不可逆转变和其孔隙结构的坍塌,增大了高温煅烧时磁性铁氧化物催化剂的比表面积和比孔容,合适的煅烧温度为400℃;该煅烧温度下,催化剂低温活性最佳,反应温度高于220℃、空速比60000h-1时可获得80%以上的NOx转化效率。 相似文献
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Zhichao Tao Yong Yang Mingyue Ding Tingzhen Li Hongwei Xiang Yongwang Li 《Catalysis Letters》2007,117(3-4):130-135
Calcination behaviors play an important role in Fischer–Tropsch (FT) performance over a slurry iron–manganese catalyst. The
present study was undertaken to investigate the effects of calcination behaviors (calcination temperature, heating rate and
calcination atmosphere) on the textural properties, reduction/carburization behavior, bulk phase structure and FT synthesis
performances over precipitated Fe–Mn catalysts. N2 physisorption, X-ray photoelectron spectroscopy (XPS), H2 thermal gravimetric analysis (TGA) and M?ssbauer effect spectroscopy (MES) were used to characterize the catalyst. It is
found that increasing calcination temperature and heating rate lead to low surface area and high enrichment of Mn on the catalyst
surface. High calcination temperature also increased the crystallite size of α-Fe2O3 and suppressed the reduction/carburization of the catalysts in H2 and syngas. Low calcination temperature and low heating rate promoted the further carburization of the catalyst and increased
the activity during FT process. High calcination temperature and low heating rate restrained the formation of CH4, increases C5+ selectivity and improved the selectivity to light olefins. In addition, calcination in argon could improve the carburization
and increase FT activity of the catalyst. The present iron–manganese catalyst with lower calcination temperature, lower heating
rate and calcined in argon is optimized for its FT performances. 相似文献
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焙烧温度对Au/Fe2O3-ZrO2水煤气变换催化剂的影响 总被引:1,自引:1,他引:1
采用共沉淀法制得Au/Fe2O3-ZrO2水煤气变换催化剂。研究了焙烧温度对催化剂的水煤气变换反应性能的影响。并对样品进行了BET、XRD和TPR表征。结果表明,焙烧条件对催化剂的结构和催化活性均有显著影响,焙烧温度越高,催化剂载体结晶度越大,被还原的难度越大,催化剂对低温水煤气变换反应的催化活性越低。Au/α-Fe2O3-ZrO2催化剂的最佳焙烧温度为300 ℃。在此温度下焙烧的催化剂,其载体主相为无定形态,催化活性较好。 相似文献
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Effects of co-existence of H2O, CO2, and SO2 in the reaction gas on the catalytic performance of cobalt containing silicate having ZSM-5 (MFI) structure (Co-silicate) were studied. Water vapor retarded only the hydrocarbon conversion to CO2 but no effect was observed on NO conversion. Addition of CO2 or SO2 did not affect the reaction. The stability of H-Co-silicate against H2O, CO2, and SO2 was ascribed to the state of metallic active species which were stabilized by incorporation into the high siliceous MFI structure. 相似文献
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不饱和烃硅氢加成催化剂固载化研究进展 总被引:3,自引:2,他引:1
综述了各类负载过渡金属的催化剂体系及其在不饱和烃硅氢加成反应中的应用。负载过渡金属的催化剂具有良好的可回收性和选择性,研究主要集中在开发价廉、使用安全、环境友好和高催化性能的活性炭、氧化物或有机聚合物等负载过渡金属催化剂,并取得很好的结果。 相似文献