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采用碱熔-碲共沉淀分离富集,用电感-耦合等离子体发射光谱法(ICP-AES)测定精细化工废催化剂不溶渣中的铂、钯、铑含量。系统考察了碱熔解和碲共沉淀富集分离的条件,研究了碲富集物中的主要元素和比例,确定了ICP-AES法测定铂、钯、铑的条件。结果表明,碱熔-共沉淀能够充分分离富集样品中的铂、钯、铑;测定催化剂不溶渣中653~3652 g/t铂、447~3804 g/t钯、539~6433g/t铑时,相对标准偏差(RSD)、样品加标回收率分别为铂0.84%~1.78%、97.0%~99.4%,钯1.05%~1.82%、97.0%~100.6%,铑1.00%~2.12%、98.2%~100.4%。方法分析快速、易于掌握,已用于生产分析中。 相似文献
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铂耗和氨耗是硝酸生产的主要技术指标。在流动氧气氛模拟条件下,以及800~950℃的硝酸生产实际氨氧化环境中,Pt-Rh二元和Pt-Pd-Rh三元合金及其催化网的失重和铂耗均遵循相同的模式,即ΔW/S=Kt2/3与ΨΣ=K't2/3。工厂实际测定数据表明,在常压氨氧化法生产硝酸过程中,Pt-12Pd-3.5Rh合金催化网的铂耗为0.044 g Pt/t(HNO3),比Pt-4Pd-3.5Rh合金催化网的铂耗(0.061g Pt/t(HNO3))低28%;在中压氨氧化法生产硝酸过程中,Pt-12Pd-3.5Rh合金催化网的铂耗为0.121g Pt/t(HNO3),比Pt-5Rh和Pt-10Rh合金催化网的铂耗(0.15~0.153 g Pt/t(HNO3))低21%,而其氨耗比后者降低3%~7%。研究结果证明,在Pt-Rh合金中添加钯或在Pt-Pd-Rh合金中增加钯含量明显降低催化合金的铂耗。 相似文献
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1.引言铂钯铑合金材料有着极广泛的应用。这些材料在使用过程中,由于受到高温或其他恶劣环境的影响而被腐蚀和污染,从而失却原有卓越的物化特性和催化特性。从废料中回收铂钯铑及其合金,在贵金属生产中占据重大的比例。不过,某些材料可以用简单的方法再生,某些材料则必须经历十分复杂的分离提纯工艺之后才能重新使用。本文根据不同的分离提纯方法,综述其工艺原理及应用状况,希望有益于同行。 相似文献
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建立了一种以碱熔-碲共沉淀分离、电感耦合等离子体发射光谱(ICP-AES)测定等离子熔炼合金样品中铂、钯和铑含量的方法。研究了样品处理和测定条件。结果表明,样品与过氧化钠混匀,在730℃马弗炉中保温25 min后,熔融物可用稀盐酸完全浸出;在盐酸介质中,加入碲溶液和二氯化锡溶液微沸30 min,所得铂、钯和铑共沉淀充分;在选定条件下,对铂、钯和铑含量为0.5~7.0、2.0~40.2和0.2~7.0 g/kg的样品,测定相对标准偏差(RSD)分别为0.44%~1.52%、0.58%~1.06%和0.61%~1.98%,加标回收率分别为99.4%~101%、99.1%~100.5%和98.3%~101%。 相似文献
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综述硝酸生产过程中铂合金催化网的损耗以及回收铂的原理与方法,讨论了高钯合金捕集网回收铂的原理、效率和效益等问题。 相似文献
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众所周知,在热循环次数一定的情况下,铂合金的耐热性取决于它的成分。因此,在研制新型多组元铂合金时,必须确定它在经常性热循环作用下的工作性能。本文研究了铑含量(5~20%)和钯含量(5~25%)对二元铂合金和三元铂合金 相似文献
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铂合金催化网焊接参数分析 总被引:1,自引:0,他引:1
在铂合金催化网的制造中,一般采用下料拼焊的方法满足幅宽与网径的要求。催化网在应用中,要经受高温、氧化、压力、冲击、摩擦磨损的作用,本文据此对催化网的焊接过程参数进行一般分析。 相似文献
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在H厂生产硝酸的2套机组4台氨氧化常压炉中用Pt-Rh或Pt-Pd-Rh针织催化网作实验,并将稀土强化Pt-Pd-Rh针织催化网与该2种催化网进行了应用比较.用化学分析、光谱定量、光电子能谱、扫描电镜等方法分析了样品的组成及状态.结果表明,优化配套的稀土强化Pt-Pd-Rh针织催化网转化效率高、吨酸铂耗低、使用寿命长,合金中Pt高温氧化轻微,Rh的表面氧化及富集减弱,催化效果明显.提出了氨氧化常压炉用铂合金针织催化网的配套措施. 相似文献
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《Synthetic Metals》2007,157(13-15):592-596
Electrochemical oxidation of glucose on gold–platinum nanocomposite electrodes and platinum-modified gold electrodes was investigated with cyclic voltammetry. Gold–platinum nanoparticles were prepared by reducing aqueous solutions containing chlorauric acid and chloroplatinic acid, and the electrodes were obtained by depositing the gold–platinum nanoparticles from the colloidal solutions onto substrates. The gold–platinum nanocomposite electrodes display high electrocatalytic activity for the glucose oxidation in alkaline solution, showing 0.30–0.35 V negative shift in peak potential as compared with bare gold electrodes, and maintain stable catalytic activity in the reaction. The results of experiments indicate that both gold and platinum act as the dehydrogenation site and gold also functions to regenerate platinum from poisoned platinum. Surface modification of gold electrodes by platinum deposition also increases electrocatalytic activity of the electrodes for the glucose oxidation, showing about 0.10 V negative shift in peak potential, but a gradual decline in reactivity is observed. 相似文献
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M. R. Tarasevich V. A. Bogdanovskaya Yu. G. Gavrilov G. V. Zhutaeva L. P. Kazanskii E. M. Kol’tsova A. V. Kuzov O. V. Lozovaya A. D. Modestov M. V. Radina V. Ya. Filimonov 《Protection of Metals and Physical Chemistry of Surfaces》2013,49(2):125-144
Creation of multicomponent catalytic systems is the main way to decrease the content of or completely replace Pt in fuel cell cathodes. Compared to the conventional catalytic systems, production of PtCoCr catalysts on different substrates (XC-72 carbon nanotubes, TiO2) differs in high-temperature conditions and the use of nitrogen-containing transient-metal precursors. According to electrochemical and structural studies, during synthesis and subsequent treatment, alloy nanoparticles with a core-shell structure enriched in platinum are formed on a carbon material doped with nitrogen. The ligand effect of the alloy core results in an increase in the electron density of the platinum d-level, acceleration of oxygen reduction, and deceleration of water molecule discharge and platinum corrosion. A architecture of membrane electrode assembly involving PtCoCr-based active layers of varying composition is developed for fuel cells operating at a temperature of 65°C in hydrogen-air and hydrogen-oxygen environments. In both cases, the use of PtCoCr instead of monoplatinum catalysts enabled us to halve the platinum consumption at the same discharge current density and specific power. The results of life testing and potential cycling of membrane electrode assemblies under severe conditions showed that the resistance of PtCoCr systems is not inferior to platinum. 相似文献
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Catalytic convertors based on the use of platinum, palladium and rhodium play a major role in the cleaning of automobile emissions.
Gold, when dispersed as nano-sized particles, has demonstrated significant activity in the conversion of toxic components,
including carbon monoxide, unburnt hydrocarbons and nitrogen oxides, in engine emissions and some advantages over the platinum
group metals. Some research outcomes on the application of nano-sized gold for the conversion of these components are reviewed.
Several key issues in relation to its performance and applicability in catalytic convertors such as low-temperature activity
and thermal stability and the possibilities of substituting platinum group metals for automobile emission control with gold
are discussed. 相似文献