钨铼合金电化学溶解工艺研究

采用电化学溶解法对某钨铼合金废料在氢氧化钠电解体系中的溶解过程进行研究。考察了电流密度、电解液碱度、温度、电解液钨离子浓度对电解过程的影响。实验结果表明,在阳极电流密度400 A/m~2、氢氧化钠浓度300 g/L、电解液温度40～45℃的条件下平均槽电压为2. 5 V,合金电化学溶解率可达98%,使得大部分钨、铼以阴离子状态转入溶液中,完成钨铼合金的高效溶解,工艺简单高效,可实现工业化生产。     

铼及其合金的电镀方法

前言 1925年6月,柏林物理工艺试验局分析化学家诺达克(Noddack.W.)和塔科女士(Tacke.I.)分析挪威产的铌铁矿石时,从中提取出周期表第75号元素的氧化物。在观测其X射线光谱时,显示出75号元素的特征谱线。他们把75号元素命名为Rhenium,符号Re(中译名铼),是取莱茵河之意。尽管元素铼发现很晚,但由于其独一无二的性能,特别是它有异常低的蒸汽压,被广泛用在电子、无线电技术和电真空工业中,为了保护电真     

从钼精矿焙烧烟尘中分离回收稀有金属铼

通过采用伯胺N_(1923)与中性膦TBP组成的协同萃取体系,分离回收钼精矿焙烧烟尘中微量铼的工艺流程,比较了此体系在不同条件下对铼（Ⅶ）、钼（Ⅵ）等离子的萃取效率和分离效果。铼在萃取过程中浓缩了20倍以上,整个回收工艺流程简单、分离效果较好。     

抗高温氧化耐蚀的高铼合金镀层

金属铼的抗热震性、抗高温、抗氧化及耐腐蚀性能优异。用来制造各类燃烧器的部件，诸如火箭发动机燃烧器及高温喷嘴等。在制备铼合金镀层方面，无论是在成本或者技术易于实现方面，电镀方法都优于物理沉积技术和热喷涂技术。本发明提供一种电镀高铼合金镀层的方法，该方法采用一种含铼酸根的电解质水溶液。镀液组成如下：过铼酸根离子0．1～0．8mol／L；合金元素离子如铁、镍、钴及铬离子中的一种或多种C为0．005～2．000mol／L；0．0001～5．0000mol／L锂或钠离子；至少一种有机酸如羧酸、羟基羧酸和氨基酸，     

辉钼矿中钼和铼分离过程研究

采用D201树脂对辉钼矿氯酸钠浸出体系所得反萃液中的钼、铼吸附分离性能进行考察。试验结果表明,树脂对溶液中的铼具有良好的吸附选择性,在吸附温度为30℃,pH=8的条件下吸附1 h,钼、铼吸附率分别为3.26%、93.18%,分离因子为197.68,能够满足钼、铼分离提纯的需要。吸附过程符合Boyd液膜扩散方程,树脂对钼、铼的吸附过程受液膜扩散控制。     

从辉钼精矿中提取钼,铼的研究

本文阐述全湿法(氧气压煮法)从辉钼精矿中制取仲钼酸铵和高铼酸铵的新工艺流程,具有收率高(钼95.08％、铼96.28％)、原材料单耗低、产品质量好、技术经济指标先进的优点。     

电感耦合等离子体原子发射光谱法测定钨铼合金中铼含量

加入过氧化氢溶解钨铼合金试样,经电感耦合等离子体原子发射光谱法对钨铼合金中铼元素的含量进行测定,铼元素分析谱线为221.426 nm,基体匹配法将基体钨带来的干扰影响加以消除,铼质量分数在0%～3%时光谱强度线性关系良好,线性系数超过0.999,定量下限0.0040%。测定结果相对标准偏差低于2%(n=11),样品加标回收率96.0%～102.0%。该方法优势较为突出,主要体现在样品处理过程简单方便、测量结果准确快速,工厂生产钨铼合金样品测定需求可得到很好的满足。     

活性炭吸附法分离铼钼的研究

活性炭吸附法分离铼钼的研究表明,调整吸附液的pH值,使铼钼能有效分离,且当pH>8.2时,分离系数SRe/Mo>3042,铼的吸附符合Freundlich等温式,即lga=0.69+0.81lgc。     

黑钨渣硫酸浸钪及浸出过程中草黄铁矾法抑制铁浸出

通过单因素实验考察了黑钨渣硫酸浸钪规律. 结果表明,在温度90℃、酸渣质量比1.2:1、硫酸浓度29%(w)、反应2.5 h条件下,钪浸出率达88%,铁浸出率为98%. 在上述最佳浸出条件下通过调整反应过程料浆的酸度,探究了钪浸出和铁的草黄铁矾法抑制浸出规律. 结果表明,在温度90℃、硫酸浓度29%(w)、总硫酸加入量为1.0倍渣量(质量比)、一段加入0.8倍渣量的硫酸、反应2.0 h后加入剩余硫酸再反应0.5 h条件下,钪浸出率为87%,铁浸出率由98%降至57%,实现了铁抑制浸出.     

富硼渣硫酸浸出实验研究

以硼铁精矿含碳球团还原熔分得到的富硼渣为原料,研究了其物相成分,并进行硫酸浸出实验,探究了硫酸用量、反应温度、反应时间及液固比对硼浸出率的影响。结果表明,该富硼渣中三氧化二硼的质量分数达到20%,主要含遂安石相和橄榄石相。硫酸浸出实验中,硼浸出率随着硫酸用量、反应温度和反应时间的增加而增大,随着液固比的增大而减小。当硫酸用量为理论用量的80%、液固体积质量比为8 mL/g、反应温度为40 ℃、反应时间为60 min时,富硼渣中硼的浸出率达到93.56%。     

镍基含铼废合金氧化酸浸工艺

在硫酸体系中,采用熔融雾化制粉、硫酸体系双氧水氧化酸浸工艺浸出铼,钨钽等稀有金属富集在渣中,研究了酸度、双氧水用量、温度、粒度、液固体积/质量比、时间对浸出的影响. 结果表明,最佳浸出条件为：在硫酸体系中,废合金雾化粉20 g,粉末粒度71~100 mm,温度75℃,液固比8 mL/g,硫酸浓度3.5 mol/L,滴加30%双氧水65 mL,反应6 h. 该条件下铼、镍和钴的浸出率均超过99%,钨钽浸出率均低于1%,钼浸出率为28%,实现了铼浸出与稀有金属在渣中富集.     

Tungsten and Rhenium Sorption Study on Alumina to Prepare 188W/188Re Generators

Abstract

Rhenium-188 is a radionuclide with favorable physical characteristics suitable for radiotherapeutic purposes (T_1/2 16.9 h, E_βmax 2.12 MeV; E_γ 155 keV (15%)) for radiotherapeutic purposes and can be continually obtained from ¹⁸⁸W/¹⁸⁸Re generator systems. The preparation conditions of an alumina based ¹⁸⁸W/¹⁸⁸Re generator are reported. Initially, the W and Re sorption behavior on alumina in NaCl and HCl medium was performed evaluating the following parameters: medium pH, alumina size particle, sorption capacity, and kinetic. Re-188 is not adsorbed in HCl and NaCl medium whereas W-188 is strongly adsorbed in both media at pH < 5. The strongest sorption of W was obtained in alumina with a particle size of 0.075–0.048 mm. The weight capacity of alumina is approximately 0.337 meq/g and the sorption equilibrium in static conditions is attained after 18 hours. This data was used to construct and evaluate alumina ¹⁸⁸W/¹⁸⁸Re-generators for a period of six months.     

Decomposition of NO on Tungsten Carbide and Molybdenum Carbide Surfaces

The decomposition of ¹⁵NO on C/W(111), C/W(110), and on monolayer and bulk C/Mo/W(111) surfaces is compared based on temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES) measurements. Our results indicate that the decomposition of ¹⁵NO occurs readily over all surfaces, and the only ¹⁵N-containing reaction products are ¹⁵N₂ and ¹⁵N₂O under our experimental conditions. Much higher surface reactivity for ¹⁵NO decomposition was observed over the more open-structured C/W(111) surface, with a value of 0.68 ¹⁵NO/W, in contrast to the surface reactivity of 0.24 ¹⁵NO/W over the close-packed C/W(110) surface. The selectivity of these two ¹⁵N-containing reaction products depends on the structure of the substrates as well. The more open-structured C/W(111) surface favors the production of ¹⁵N₂, with a product selectivity of ¹⁵N₂ being approximately 87%. In contrast, the selectivity to ¹⁵N₂ is only about 52% on C/W(110). In addition, we have investigated the decomposition of ¹⁵NO on C/Mo surfaces that were epitaxially grown on W(111). The selectivity of ¹⁵N₂ on C/Mo/W(111) surfaces is 88%, which is very similar to that observed on C/W(111). Finally, the general similarity between the DeNOx chemistry on carbides and on Pt-group metals will also be discussed.     

三核钼钨簇合物的循环伏安法研究

本文利用循环伏安法在铂电极上研究了三核钼钨簇合物（〔Ｍｏ３Ｌ〕２＋ ,〔Ｗ ３Ｌ〕２＋其中Ｌ＝ 〔（μ３－ Ｏ）２（μ－ ＣＨ３ＣＯＯ）６（Ｈ２Ｏ）３〕的电化学性质及其对电化学性质的影响因素。     

Hardness of Polycrystalline Tungsten and Molybdenum Oxides at Elevated Temperatures

Vickers hardness of WO₃, W₁₈O₄₉, and MoO₂ is reported for temperatures up to 800°C. Polycrystalline samples of the oxides were prepared by hot-pressing, and hardness was determined using a Vickers hardness tester modified for high-temperature applications. The hardness of a heavily deformed tungsten rod was also measured as a reference.     

Molybdenum Oxycarbide and Tungsten Oxycarbide Coatings on Silicon Carbide Fibers

The strength and toughness of fibrous composites depend on the interface properties which control the bonding between the fibers and matrices. One method of controlling the interface involves coating the fiber with an appropriate material. In a previous study, it was found that there is a definite advantage in using low coating temperatures to prevent fibers from degrading. We therefore were interested in a report that Mo₂C could be deposited from Mo(CO)₆ at temperatures as low as 300° to 475°C. Our studies indicated that the material was not Mo₂C, but an oxycarbide, which, with an analogous tungsten oxycarbide coating, was applied to SiC yarns. Both oxycarbides could be converted to the metals by heat-treating in N₂.     

含锰冶炼粉尘的加压硫酸浸出

研究了含锰收尘灰加压浸出的影响因素. 结果表明,优化浸出工艺条件为：液固比5 mL/g,初始硫酸浓度120 g/L,浸出温度120℃,体系压力0.8 MPa,锰收尘灰/硫铁矿质量比1:0.5,浸出时间2 h,搅拌转速500 r/min. 在该条件下,Mn浸出率约96.1%,Fe浸出率仅7%左右,终酸残余率约34.9%. 该浸出工艺效果良好且稳定,Mn与其他杂质元素的分离效果良好,可取得常压浸出条件难以取得的理想浸出效果.     

硫酸浸取法从硫铁矿烧渣中提取铁的研究

研究了在常压下采用硫酸浸出法提取硫铁矿烧渣中铁的工艺流程及其主要的参数对铁提取率的影响。实验结果表明，影响铁提取率的因素按其重要性排列为：温度、时间及硫酸质量分数。当硫酸质量分数为55％、温度110℃、浸取在2h以上时，铁的提取率近50％。本方法设备及流程简单，成本低，无二次污染。