共查询到19条相似文献,搜索用时 296 毫秒
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通常情况下,矿石中氧化铝的前处理一般依据GB/T14565-93及DZG93-05分别采用Na2CO3及Na OH碱熔前处理溶矿,EDTA络合返滴定容量法测定矿石中氧化铝的含量,结果准确,重现性好,却费时相对较长。本文主要提出了采用盐酸、硝酸、硫酸、高氯酸、氢氟酸,加热溶解,盐酸、硝酸、王水浸提等多种矿石中三氧化二铝的熔(溶)矿及分析测试方法,引入的氢氟酸有效打开矿物中的硅酸盐,使溶样更加完全,测试体系更纯净,操作简便。试验结果表明,酸溶溶矿样品更适于采用DZG93-05EDTA络合醋酸锌容量法(p H~5.9)及ICP-OES法进行测定,对于氧化铝含量低于20%的矿石样品,并不含有一水硬铝石的矿物,酸溶溶矿法测定矿石中氧化铝的含量结果可靠,有较强的普遍性和适用性。 相似文献
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对于铌钽精矿中钨的定值,用传统测定钨的方法会对结果造成极大的误差,因此,开展了铌钽精矿中3种钨的定值方法的研究。通过研究混酸溶矿对测定钨的适用性,并讨论酸溶体系的稳定性,建立了混合酸溶-电感耦合等离子体发射光谱体系;通过研究碱熔对测定钨的适用性,采用Na_2O_2-NaOH混合熔矿,并用氯化钠溶液提取代替常规的水溶液提取,进而建立了碱熔-电感耦合等离子体发射光谱体系以及碱熔-硫氰酸盐比色法测定体系。3种方法均能满足定值要求,但混酸溶矿体系操作相对简单,故一般推荐此方法。该方法的精密度(RSD,n=12)为4.85%~7.01%、准确度(RE)为-0.83%~2.69%,方法操作简便、快速准确、成本低,能满足铌钽精矿中钨的分析质量要求。 相似文献
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采用了高温熔融法制备了Bi2 O3-B2 O3-ZnO-Al2 O3-SiO2系银浆玻璃玻璃粉,添加少量CeO2作稳定剂,分别采用铂金坩埚、石英坩埚、刚玉坩埚在1100℃条件下熔制,系统研究了在不同坩埚熔制时对该系玻璃的玻璃化程度、热学性能及化学稳定性的影响.结果表明:在添加CeO2稳定剂的前提下,该系玻璃在铂金坩埚、石英坩埚、刚玉坩埚中均能熔制出均匀透明玻璃.在铂金坩埚中熔制时,玻璃的玻璃化程度较高.在石英坩埚中熔制时,较多的SiO2融入该系玻璃粉内,提高了其玻璃化转变温度,但其膨胀系数明显降低,其热稳定性与化学稳定性也有大幅度提高.在刚玉坩埚中熔制时,刚玉坩埚中少量Al2 O3融入玻璃粉内,提高了该系玻璃粉的玻璃化程度,对其热稳定性与化学稳定性的提高也有一定的促进作用. 相似文献
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碱熔-电感耦合等离子体质谱法测定镓矿石中镓、钼、钨 总被引:1,自引:0,他引:1
以氢氧化钠-过氧化钠为熔剂,对镓矿石样品进行前处理。电感耦合等离子体质谱法测定镓矿石中镓、钼、钨。试验结果表明,本方法相关系数介于0.999 2~0.9997之间,测定精密度RSD%低于1.94%,回收率在97.7%~104.3%之间。该方法具有线性范围广、分析速度快、检出限低、准确度和精密度高等优点,适合镓矿石中镓、钼、钨的测定。 相似文献
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文章主要研究在各种不同前处理条件下同时测定钨、钼两种元素,找到了简便、通用的前处理方法;HCl+HNO3+HF+HClO4熔矿,稀酸提取;或者Na2O2高温熔融,水提取,上述处理方法均可实现钨、钼的同时测定。钨标准回收率为97.8%~102.2%,钼标准回收率为98.8%~102.0%。 相似文献
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目前国内对硅钙质胶磷矿的浮选,多数利用S_(808)(粗菲磺化物)作碳酸盐脉石的抑制剂。但对S_(808)的污染问题尚有争议。本文主要介绍利用木素磺酸钙作碳酸盐抑制剂,选别硅钙质胶磷矿的试验研究结果。 以陕西省茶店磷矿南北两翼混合矿样为试验矿样,进行了小型闭路试验和扩大试验,结果表明:木素磺酸钙可以有效地抑制碳酸盐脉石,与使用S_(808)时所得选别指标大体相近。 (一)矿石性质 茶店磷矿属中低品位沉积磷块岩矿床。矿石可划分为鲕状、假鲕状灰质磷块岩,致密条带状的灰质磷块岩、硅质磷块岩、锰质磷块岩等自然类型。嵌布粒度细,碳酸盐含量高,是该矿石的特点。 相似文献
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Graphite encapsulated metal (GEM) nanocrystal is a core-shell structured nanomaterial which is capable of surviving in severe environments, such as strong-acid or strongly-oxidizing conditions. Many researches have proven GEM to be useful for its potential multiple applications. However, there is a serious problem: its low production rate hinders future research on possible applications. Although the tungsten arc-discharge method produces more GEM nanoparticles than all the other methods do, the production rate remains unsatisfactory.Based on a previous study, it is known that the temperature gradient in the molten liquid metal pool during arcing is inadequate, i.e., the bottom is cooler than its surroundings, thus preventing the occurrence of convection and the homogeneous evaporation process. In this study, a new crucible design, with a thermal insulating alumina piece at the bottom of the graphite crucible, effectively modifies the temperature gradient inside the molten liquid pool. As a result, the as-made production rate approximately quadruples. This work demonstrates, as attested by experimental evidence, how an alumina piece can effectively change the temperature profile in the crucible and facilitate the synthesis of GEM in a tungsten arc-discharge system. 相似文献
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Jianbo Liu Gai Zhang Zuchao Meng Bo Qiao 《Journal of the American Oil Chemists' Society》2009,86(10):967-970
A pressurized polytetrafluoroethylene (PTFE) bomb method for the digestion of trace nickel in hydrogenated cottonseed oil
prior to its determination by graphite furnace atomic absorption spectrometry (GFAAS) has been developed. Currently, the methods
outlined in United States Pharmacopeial 28 (USP28) and British Pharmacopeial (BP2003) methods are recommended as the official
methods for analyzing nickel in hydrogenated cottonseed oil. However, when using these methods, the samples were easily tarnished
during sample pretreatment when using a silica crucible. In contrast, when using a platinum crucible, hydrogenated cottonseed
oil acting as a reducing material may react with the platinum and destroy the crucible. In order to avoid the tarnish with
a silica crucible and the risk when using platinum, the technology of a pressurized PTFE bomb method was applied in the digestion
of nickel in hydrogenated cottonseed oil. The results showed that hydrogenated cottonseed oil can be digested completely by
the optimal combinations of HCl (0.1 mL) and HNO3 (0.5 mL). The digested solution was investigated using graphite furnace atomic absorption spectrometry. 相似文献
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介绍了一种改进的测定氟硅酸钠产品中铁含量的分析方法。采用聚四氟乙烯坩埚代替铂金器皿,测定结果与专业标准方法差值很小,完全可以满足分析要求;同时可缩短分析时间,简化测定手续,节省分析费用。已在实际生产中应用,取得了良好的效果,值得在同行业中推广应用。 相似文献
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微波技术在冶金中的应用 总被引:1,自引:0,他引:1
综述了微波在冶金领域中的矿物预处理,金属氧化物的碳热还原反应以及矿物浸出方面国内外的一些研究成果和进展,认为微波作为一种清洁、干净有效的能源,在冶金领域中具有广阔的应用前景。 相似文献
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《Journal of the European Ceramic Society》2023,43(4):1714-1722
The interfacial behavior between CaAl12O19-MgAl2O4 spinel (CA6-MA) crucible and molten wrought Ni-based superalloys during the vacuum induction melting process have been comprehensively investigated, with Al2O3 crucible included for comparison. Experimental and theoretical results suggest that CA6-MA crucible exhibits higher thermodynamic stability and poor wettability to the superalloy melt. Benefited from these merits, the superalloy ingot with cleaner surfaces and more metallic luster is obtained in the CA6-MA crucible. Furthermore, the total oxygen content in the superalloy ingots obtained from CA6-MA crucible is 17.9 ppm, which is considerably lower than that from Al2O3 crucible (29.7 ppm). These results indicate that CA6-MA crucible can be a promising candidate for melting wrought Ni-based superalloys. 相似文献
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介绍了高密度沉淀池的结构特点、工作原理及其作为火力发电厂原水预处理设施的优点,并将其与传统原水预处理设施进行了综合比较,结果表明:高密度沉淀池对浊度和有机物的去除率高,对水质突变适应能力强,运行成本低。 相似文献