共查询到19条相似文献,搜索用时 187 毫秒
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采用激光剥蚀-电感耦合等离子体质谱法(LA-ICP-MS)测定汽车尾气催化剂中铂、钯、铑的含量。将催化剂粉末与吸附贵金属的硅胶粉末混合压片制备样品,分析了制备样品表面贵金属元素分布均匀性。采用面扫描模式进行测定,以标准加入法对结果进行计算,3种元素测定结果与标准样品认定值基本一致。3种元素测定下限(μg/g)分别为铂1.1、钯19.4和铑1.4。对4组不同含量的汽车尾气催化剂样品进行分析,结果与采用标准HJ 509-2009湿法分析测定结果一致。方法可应用于汽车尾气催化剂中贵金属元素含量的测定。 相似文献
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采用辉光放电质谱法(GDMS)测定纯铂中杂质元素含量,获得了仪器最佳工作条件,并对比了不同样品制备方式对测定结果的影响。结果表明,GDMS对大部分杂质元素的检出限低至10-9量级,对含量在10-6的杂质元素,测定相对标准偏差(RSD)在10%以内,可满足高纯铂的测定要求。与ICP-AES和ICP-MS测定结果对比表明,采用仪器提供的相对灵敏度因子(RSF)所得到的半定量结果与前二者存在一定的偏差,有必要采用标准样品进行RSF的校准。纯铂样品采用金属片、铟片粘附或粉末压片均可得到相似的检测结果,其中粉末压片法在标样制作中具有较好的应用前景。 相似文献
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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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为了对地球化学样品中铂族元素快速、准确地进行分析测试,在实验的基础上,建立了小铅试金富集-电感耦合等离子体质谱(ICP-MS)法测定地球化学样品中铂和钯的方法。以碱式碳酸铅代替氧化铅,以硝酸银为铂钯捕集剂,取样量为10 g时,试金配方具有较宽的使用范围;灰吹后的银合粒经硝酸溶解后以盐酸沉淀分离银,可有效去除测定干扰元素;采用ICP-MS可准确测定试液中的铂钯含量。方法加标回收率符合要求,对标准样品的测定结果与推荐值相符,适用于批量化探样品中痕量(0.1 ng/g)的铂和钯的分析。 相似文献
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《中国有色金属学报》2017,(3)
以亚硫酸钠为还原剂,研究采用控制电位还原法回收氯化浸出液中的贵金属。结果表明:当控制金还原电位为530~550mV时,氯化浸出液中98%以上的Au将被还原沉淀至粗金粉中,同时Pt、Pd和Te基本不被还原沉淀,所得粗金粉中Au含量在98%以上,Se、Te、Cu和Pb等杂质的含量均低于0.10%(质量分数),而且该金还原电位对不同Au浓度或酸度的氯化浸出液都具有良好的适应性;然后当控制铂钯还原电位为390~420mV时,金还原后液中的Au、Pt和Pd将被还原沉淀至1mg/L以下,而Te基本不被还原,所得铂钯精矿中贵金属含量高、杂质含量少,且所确定的铂钯还原电位对不同铂钯浓度或酸度的金还原后液以及反应温度均具备较好的适应性。可见,通过控制电位还原,可将氯化浸出液中贵金属选择性沉淀并与其他元素初步分离。 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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Ag—10Pd合金超细粉末的制造及应用 总被引:9,自引:3,他引:6
将一种化合物加到硝酸银和硝酸钯混合溶液中,共沉淀出中间体,还原得到Ag-Pd合金粉末。一定条件下再处理,得到Ag-10Pd内电极粉末。用该粉末配制的浆料可用于制备性能达到标准的多层陶瓷电容器。 相似文献
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含有铅、铋、锑、金、银、铂和钯等元素的粗铅采用火试金重量法测定时,不能同时得到铂和钯的含量数据。采用铅箔包裹样品置于灰皿中,于860℃直接灰吹得到贵金属的合粒(含少量铋、铅),合粒可用硝酸溶银,补加过量盐酸溶解金、铂和钯,试液用电感耦合等离子体原子发射光谱仪(ICP-AES)测定其中金、铂、钯和主要杂质元素(铋和铅)的含量,差减可得到银的含量,实现对金、银、铂和钯的同时测定。金、银、铂和钯的测定结果相对标准偏差(RSD)均小于2.95%,加标回收率在98.0%~99.8%之间,满足生产测定的要求。 相似文献
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4160 mm特大型水电台阶法兰锻件的吨位重、规格大、法兰直径及相邻截面差大,采用传统的芯棒直接卡台+分段扩孔成形法很难保证最终成形尺寸。通过综合分析特大型水电台阶法兰类锻件的关键成形方法和控制难点,创新锻造工艺,首次提出了"实心制坯+分段扩孔成形"的控制新方法;确定实心制坯环节采用带钳把卡台锻造,且下料后增加平整端面工序,分段扩孔环节的压下量按照30~45 mm控制,且每火次扩孔后增加收孔工序;并结合工艺性分析,建立了塑性有限元和结构有限元分析模型,仿真并分析了实心制坯和分段扩孔过程的金属流动规律、金属流动速率及各部位的金属流动速度差,预测了新方案的工艺参数和过程控制,以及实心制坯、分段扩孔的成形效果和质量。通过生产试制,验证了该工艺参数及成形工艺的合理性。 相似文献
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本文创制渣池有衬节能、叠加直流电化学精炼、纵向结晶排夹杂三结合的优质节能新型电渣重熔炉.研究了叠加直流电流密度对合金成分和对去硫、去气的影响.实验结果表明,新型电渣单位电耗降低达41%;在无保护气氛下电渣重熔,GH49,GH37合金中活泼元素成分可不烧损;可有效地降低合金中O,N,S含量达到10ppm;电渣锭轴向结晶,组织致密,二次枝晶轴间距比通常电渣锭缩短近1/3,显著改善合金偏析. 相似文献
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采用纳米钯黑做造孔剂并与海绵钯混合进行等离子脉冲放电烧结(SPS)的方法制备多孔钯块体材料。结果表明,纳米钯黑材料在500~550℃受热后会产生明显的收缩,具有良好的造孔效果。由于采用该方法不引入任何杂质,故可在550℃时制备出洁净度与孔隙率(87.88%)高、力学性能好的多孔钯块体材料。该方法也可为其它高洁净度多孔金属材料的制备提供有价值的借鉴。 相似文献
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Baokuan Li Qiang Wang Fang Wang Mingqiu Chen 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(7):1153-1165
A coupled cellular automaton–finite-element mathematical model has been developed to investigate the multiscale phenomena of the electroslag remelting (ESR) H13 steel ingot. The heat transfer equation is solved to obtain the temperature distribution and liquid metal pool profile by a coarser finite-element (FE) mesh. Then, a regular network of square cells with a much finer scale is drawn for the simulation of microstructure with the cellular automaton (CA) technique. The continuous nucleation, which is based on the Gaussian distribution, is implemented to describe the heterogeneous nucleation. The growth kinetics of the dendritic tip is taken into account by the Kure–Giovanola–Trivedi model. At each time step, the temperature at the CA cell locations is interpolated from the temperature at four adjacent FE elements. The solute transfer is calculated using the FE method. Moreover, the evolution of the multiscale phenomena with growing of the ingot is considered by the varying boundary conditions. A reasonable agreement is demonstrated between the calculation and experiment. The results indicate that the shallow U-shaped metal pool would change to the deep V-shaped metal pool with the growing of the ingot. The vertical columnar grains appear at the bottom of the ingot, and an inverse V-shaped grain structure can be observed at the upper part of the ingot. It can be inferred that improving the undercooling can refine the microstructure and motivate the growing of the columnar grain during the ESR process. 相似文献
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ZHU Ping GU Guobang QU Zhiping HUANG Yanfei YAO Wenxue 《稀有金属(英文版)》2006,25(2):99-105
Platinum, palladium and rhodium of the raw feeds extracted and separated with a new sulfoxide extractant (MSO) were studied in the paper. The pilot test results showed that the percentage extractions are more than 99% for platinum and palladium in Pt-Pd feed, and the percentage strippings are 100% and 99.2% with HCl and ammonia, respectively. The ratio of palladium to platinum is 0.0016 in stripping platinum solution, and the ratio of platinum to palladium is 0.0020 in stripping palladium solution. The percentage extraction of platinum is 99% in Pt-Rh feed, and the percentage stripping is 100%. The ratio of rhodium to platinum is 0.0002 in stripping platinum solution. Therefore, platinum, palladium, and rhodium feeds are separated effectively with MSO. 相似文献
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The electrode configuration determines the thermophysical field during the electroslag remelting(ESR) process and affects the final microstructure of the ingot. In this work, ingot with a diameter of 400 mm was prepared with two electrode configuration modes of single power ESR process, namely one electrode(OE) and two series-connected electrodes(TSCE). Finite element simulation was employed to calculate the electromagnetic field, flow field and temperature field of the ESR system. The results show that the temperature of the slag pool and the metal pool of the TSCE process is lower and more uniform than that of the OE process.The calculated temperature distribution of the ingot could be indirectly verified from the shape of the metal pool by the experiment. The experimental results show that the depth of the metal pool in the OE ingot is about 160 mm, while the depth of the TSCE ingot is nearly 40 mm shallower than that of the OE ingot. Microstructural comparisons indicate that coarse eutectic carbides are formed in the center of the OE ingot, whereas more even eutectic carbides appear in the center of the TSCE ingot. In general, compared with the OE process, the TSCE process is preferred to remelt high speed steel ingots. 相似文献