共查询到20条相似文献,搜索用时 78 毫秒
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乌克兰2006年1~11月份的钛精矿出口量与2005年同期相比增加了0.2%,达到29.887万mt。仅仅11月份,乌克兰就出口了3.008万mt精矿,比10月份的2.145万mt,和2005年11月份的2.547万mt均高出不少。11月份,乌克兰向俄罗斯出口了1.492万mt钛精矿,比10月份的出口量8970mt要高。 相似文献
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以硝酸作为氮源,钛精矿为原料,采用超声波复合高能球磨法,在不同煅烧温度下合成了硝酸掺杂的钛精矿催化剂(nitric acid-modified titanium ore,NATO)。用X射线衍射(XRD)、傅立叶红外(FT-IR)、紫外-可见漫反射光谱(UV-Vis)、差热-热重(TG-DTA)和光致发光谱(PL)分析对NATO催化剂的结构和性能进行分析和表征,确定其由钛磁铁矿、钛铁矿、TiO2、钛铁氧化物等多种物相组成;在紫外-可见光区域都具有很强的光吸收能力。不同煅烧温度下,NATO催化剂的光催化活性由甲基橙的脱色率来评价,结果表明,煅烧温度为400℃时,NATO催化剂由于表面存在较高的硝酸盐含量和较高的可见光吸收能力及合适的晶相比,而具有较高的光催化活性,500W金卤灯照射1h,可将浓度为10mg/L的甲基橙废水完全降解。 相似文献
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采用等温动力学研究的方法在1100~1300℃下对攀枝花钛精矿真空碳热还原中铁的动力学进行了研究。研究结果表明:还原温度的升高和保温时间的延长,能促进钛精矿中Fe3O4的还原以及铁的聚集长大;钛精矿中的铁在1100~1250℃保温的前期即0~30 min时,还原反应受界面化学反应控制,反应的表观活化能为207.92 kJ/mol;在1100~1200℃保温的后期即30~90min时,还原反应受内扩散控制,反应的表观活化能为521.47 kJ/mol。 相似文献
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赵世翻黄润吕晓东伍秦至武庆慧张金柱 《真空科学与技术学报》2020,(5):437-442
采用等温动力学研究的方法在1100~1300℃下对攀枝花钛精矿真空碳热还原中铁的动力学进行了研究。研究结果表明:还原温度的升高和保温时间的延长,能促进钛精矿中Fe3O4的还原以及铁的聚集长大;钛精矿中的铁在1100~1250℃保温的前期即0~30 min时,还原反应受界面化学反应控制,反应的表观活化能为207.92 kJ/mol;在1100~1200℃保温的后期即30~90min时,还原反应受内扩散控制,反应的表观活化能为521.47 kJ/mol。 相似文献
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以烧结后的La2O3、CeO2、NiO混合物片体作为阴极,高密度碳棒作为阳极,在850℃的CaCl2熔盐中,采用恒电压电解,对La0.5Ce0.5Ni5三元合金进行了制备。用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对样品的分析结果表明,经1050℃烧结的混合氧化物,在3.1V工作电压下电解12h,可以得到海绵状La0.5Ce0.5Ni5三元储氢合金。不同时间电解后样品的XRD衍射图谱显示,电解过程是逐步进行的,NiO首先在电极上还原为Ni,然后LaOCl(由La2O3与CaCl2反应生成)和CeOCl(由部分还原的CeO2与CaCl2反应生成)在新生成的Ni表面还原并形成La0.5Ce0.5Ni5合金。Ni单质的存在很可能是由于生成的LaOCl和CeOCl部分溶解在熔盐中造成损失,使得Ni量多于化学计量比。 相似文献
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Ni, Cu, Cu90Ni10 and Cu70Ni30 were evaluated as cathode materials for the conversion of nitrate to nitrogen by a paired electrolysis process using an undivided flow-through electrolyzer. Firstly, corrosion measurements revealed that Ni and Cu70Ni30 electrodes have a much better corrosion resistance than Cu and Cu90Ni10 in the presence of chloride, nitrate and ammonia. Secondly, nitrate electroreduction experiments showed that the cupro-nickel electrodes are the most efficient for reducing nitrate to ammonia with a selectivity of 100%. Finally, paired electrolysis experiments confirmed the efficiency of Cu70Ni30 and Cu90Ni10 cathodes for the conversion of nitrate to nitrogen. During a typical electrolysis, the concentration of nitrate varied from 620 ppm to less than 50 ppm NO3− with an N2 selectivity of 100% and a mean energy consumption of 20 kWh/kg NO3− (compared to ∼35 and ∼220 kWh/kg NO3− with Cu and Ni cathodes, respectively). 相似文献
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Jianmin Liu Tao Wang Qiwei Gao Weihui Jiang Lifeng Miao Guo Feng Feng Jiang 《Advanced Powder Technology》2021,32(4):998-1003
Zirconia whiskers were successfully fabricated by molten salt method, using NaVO3/NaF as composite molten salt. The effect of NaF content on the growth of zirconia whiskers were systematically investigated by XRD, FE-SEM, TEM, SAED, HR-TEM, Raman and XPS. When optimized NaF content is 10%, the obtained zirconia whiskers with monoclinic crystal structure show an length of 1–3 μm and diameters of 100–300 nm. The as-prepared whiskers preferentially grow along [0 0 1] direction and exhibit a smooth surface without distinct defects. Fluoride is proved to play an important role in the growth of zirconia whiskers. On the one hand, fluoride can be served as mass transfer agent, promoting the dissolution and precipitation of ZrO2 through the mass transfer process of fluorozirconate species. On the other hand, fluoride can act as morphology controlling agent, enhancing the anisotropic growth of ZrO2 crystals by the formation of fluorine-terminated surface. 相似文献
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H原子对固态合金化颗粒表面成份分布影响的研究 总被引:1,自引:0,他引:1
本文研究了氢化物TiH2对Fe+Ti机械合金化非晶储氢合金的表面成份偏聚和性能的影响。应用X射线光电子谱(XPS)和俄歇电子谱(AES)对样品表面由表及里逐层测量成份分布。同时应用热重分析方法研究了样品氧化性能和产物。研究结果表明,在机械合金化过程中,H原子不仅能使FeTi非晶化,同时促使表面产生明显的Fe原子偏聚。表面Fe/Ti原子比接近7。非晶FeTi(H)相的氧化分两个阶段进行,Ti原子首先氧化(833K),随后Fe原子氧化(890K)。 相似文献
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采用熔盐法在K2CO3和Na2CO3的熔盐(K2CO3/Na2CO3=45/55)中800℃并保温2h的条件下制备出了单相、纯钙态矿型结构的Na0.5K0.5NbO3粉体,运用XRD以及SEM技术对所得粉体进行了相组成及显微结构分析。结果表明:随着盐含量的增加,晶体结构从正交相转变为四方相,晶粒大小先增加而后稍微减小,并且获得较好的介电压电性:ε33^T/ε0(1kHz)=45-264,tgδ=1.5%~2.6%,Tc=402℃,Tτ-o=202℃,d33=88-98pC/N,Qm=465-574,Kp=29.09%~30.47%,在10kHz频率下,介电损耗有一点改变。NKN将有可能成为用于高频下的无铅压电陶瓷之一。 相似文献
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《材料科学技术学报》2019,35(7):1422-1431
This work mainly deals with the segregating behaviors of Sc and the growth of unique primary Al3Sc in Al-Sc alloys prepared by molten salt electrolysis. The alloys contain 0.23–1.38 wt%Sc where Sc segregation is observed. It is found that a high current density and long electrolysis time are in favor of high Sc content, and so do the high temperature and the addition level of Sc2O3. Sc content at the edge of Al based alloy (average Sc content: 0.75 wt%) can be as high as 1.09 wt%, while it is merely 0.24 wt% at the central area. The cooling rates have a strong impact on the morphology and particle size of primary Al3Sc, but a weak influence on Sc segregation. The cusped cubic and dendritic primary Al3Sc can precipitate in the prepared Al-Sc alloys. In a slightly hypereutectic Al-0.67 wt%Sc alloy, a large and cusped dendrite grows from the edge into the center. The primary and secondary dendritic arms can be as long as 600 and 250 μm, respectively. The Sc segregating behaviors in Al-Sc alloys is due to the mechanism controlled by the limited diffusion rate of Sc in liquid Al. This can involve the establishment of a near spherical discharge interface between liquid Al and the electrolyte. The Sc rich layer near Al-molten salt interface may provide the potential primary nuclei and sufficient Sc atoms for the growth of large dendritic primary Al3Sc. 相似文献