高纯六氟化钨制备工艺研究

介绍了利用氟气与钨粉为原料制备高纯六氟化钨的工艺方法和设备体系。其过程是利用电解槽电解氟氢化钾制取氟气,并采用氟化钠吸附配合深冷工艺纯化氟气,净化后的氟气与固定床里的钨粉在一定温度条件下反应合成初级六氟化钨,通过低温冷凝回收,收集的初级六氟化钨经过固化后抽真空排轻等方法进行初步提纯,然后将初步提纯的产品蒸馏至填料式精馏塔内进行深度提纯,经过多步提纯后的成品六氟化钨纯度可达99.999%以上。     

深冷技术与金属吸气材料技术相得益彰

利用深冷技术,将大流量的气体分离,用金属吸气材料去除常规技术难以去除的杂质气体。在空气分离与净化领域,深冷技术与金属吸气材料技术可以完美的结合,相得益彰。     

添加钨对金属钪中铁、镍杂质元素净化率的影响

为解决金属钪实际生产中Fe、Ni杂质高的问题,通过真空蒸馏提纯方法,并添加一定量的高纯钨作为净化剂,研究了其对金属钪中Fe、Ni杂质的净化率。结果表明,金属钪中的杂质Fe、Ni更易与钨形成固溶体而达到净化效果,在添加30%钨的情况下,Fe、Ni净化率提高了近一倍;相比于大颗粒的金属钨块,相同质量下总表面积更大的小粒径钨颗粒的净化效果更好。     

化学和熔炼精制钨时金属杂质的行为

研究了商业钨化合物中某些杂质如金属元素和气体组分的净化。试验了两种精制方法。第一种是化学精制法,如溶剂萃取、离子交换和结晶。第二种是真空熔炼法,即所谓电子束熔炼法。已发现,碱金属、碱土金属和过渡元素,很容易用化学精制法除去,而气体组分及易挥发元素则可用电子束熔炼法挥发除去。为了要生产高纯金属钨,研究各种精制方法的特点是很重要的。     

钨冶炼过程中磷、砷、硅杂质元素的分离

钨矿石中都伴生有磷、砷、硅等杂质元素。在钨精矿碱分解过程中,部分杂质元素与钨一起进入溶液。在制取纯钨化合物之前,必须净化除去这些杂质元素。下面就钨冶炼过程中净化除磷、砷、硅作些介绍。一、矿石预处理除杂质白钨精矿中的磷、砷、硫等杂质元素只要以容易与酸作用的化合物形态存在,通过两步酸浸处理后,原矿中的磷便降至200ppm     

钨液-液萃取过程中杂质的行为

钨生产过程中溶剂萃取法正日益成为通用的净化方法。然而,讨论钨本身萃取行为的文献中,实际上没有关于杂质萃取行为的任何数据。本文首次研究了限制杂质含量的理由,因为在钨萃取系统的产品中会遇到杂质含量的问题。文中只着重于叙述溶剂萃取阶段的杂质净化状况。     

从钼氧化物中去除钨的新方法

<正> 日本一家公司研究出一种从三氧化钼中分离钨,制取高纯钼粉的新方法以满足钼测射靶对原料纯度越来越高的要求。在一般的纯钼粉中,含有100～200ppm的钨,这种钼原料中钨的去除非常困难,虽然实验室中有一些净化方法,但未能用于工业生产。新方法容易分离三氧化钼中的钨,并能进一步清除其它杂质。     

钽和铌的高温提纯

与大多数杂质的气化温度比较,钽和铌的熔点很高,因此,提取的金属可在高温下进行再提纯。但是在提纯时必须注意的是,钽和铌与除惰性气体以外的所有气体均具有很大的亲和力。因此,一切高温处理须在真空或纯惰性气体下进行。对高温下不能或很难去除的杂质,例如钨、钼、锆和铪以及铌中的钽和钽中的铌必须在加工钽、铌化合物时,即还原前就     

去除三氧化钼中钨的新方法

日本一家公司研究出一种去除三氧化钼中钨的新方法。这种方法是:首先将含有钨杂质的三氧化钼用氨水溶解(PH值为6.5～7.5),得到每升含三氧化钼200～500g的溶液;然后调整PH值至2.5～4.5,将溶液加温至50℃;待溶液慢慢沉清后,上清液为纯钼酸铵,钨杂质以沉淀形式几乎完全被除去。去除三氧化钼中钨的新方法@李有观     

钨绿色冶炼工艺研究方向和技术进展

我国钨冶炼技术世界领先，但由于Na+和Cl-无法闭路循环，沿袭百年的碱（酸）浸出-净化-铵盐转型湿法工艺难以达到废水零排放要求.“钨精矿火法直接制取碳化钨”和“熔盐电解直接制取碳化钨或金属钨”工艺，在金属提纯和分离杂质方面存在难以克服的缺陷，同时存在酸洗废液排放的问题.铵盐不变体系白钨闭路冶炼工艺研究结果表明，与现行白钨碱法-离子交换工艺相比，全流程金属回收率提高2.6%，达到98.1%，APT产品加工成本下降30%，可实现白钨无酸碱闭路冶炼和杂质元素的绿色分离，过程无废水排放.     

Impurity distribution in metallic dysprosium during distillation purification

The distribution rules of impurities contents in distilled metallic dysprosium were researched,and a theoretical analysis was carried out.The research results indicated that,the content of impurity in distilled metal,such as Al and Fe,was lower in the initial stage,increased slowly in the middle stage,and increased rapidly in the last stage during the process of distillation purification.The calculated method of separation coefficient of impurity in crude metal by content of impurity in distilled metal was not suitable for high pure metals,and the modified separation coefficient was proposed,and it equaled 1/6.1 and 1/16.9 for impurity Al and Fe.The physical process of distillation was coincident with that of solidification essentially,and solute re-distribution theory in solidifying front could be used to describe the impurity distribution near evaporating surface.In the former stage of distillation purification,the diffusion of impurity in liquid metal could reach a quasi-equilibrium state,the calculated result of impurity content in distilled metal agreed well with experiments.In the latter stage of distillation process,the diffusion rate of impurity in liquid metal decreased,and the content in distilled metal was larger than the calculated result.     

仲钨酸铵蒸发结晶过程中杂质元素的析出行为

仲钨酸铵(APT)主要采用蒸发钨酸铵溶液的方式制取,是钨冶炼中最重要的中间产品,其化学质量将直接影响后续钨产品的质量.以硫磷混酸协同分解白钨所得钨酸铵溶液为原料,通过研究APT蒸发结晶过程中主要杂质离子的析出规律,获得了制备APT-0级产品所要满足的钨酸铵原料液中各杂质的浓度上限,既为钨酸铵净化工序提供了除杂深度的数据...     

Impurities especially titanium in the rare earth metal gadolinium— before and after solid state electrotransport

Gadolinium was prepared by conventional procedures of fluorination, reduction, distillation and solid state electrotransport（SSE）. The electronegativities of the metals were found to have an important influence on the electrotransport process and result of the impurity element. Meanwhile, titanium particles in the distilled gadolinium as major metallic impurities were studied by high resolution transmission electron microscopy（HRTEM） before and after solid state electrotransport. The results showed that impurities especially titanium transported from anode to cathode during SSE. In the metal before SSE, there were impurities of titanium in strip shape or embedded round shape. After SSE processing, titanium particles in the metal smaller than 50 nm in the cathode, but existed 6 to 10 times bigger in the anode.     

电子束诱导定向凝固过程中晶体形貌对杂质分布的影响

产业条件下,利用电子束诱导定向凝固技术提纯多晶硅实现晶硅尾料的循环再利用,在硅锭中包括类单晶和柱状晶两种晶体形貌。与多晶区域相比,类单晶区域电阻率和少子寿命等电学性能分布比较均匀,铁杂质的含量分布也较均匀,其质量百分数平均值为0.000031%。电子束诱导定向凝固过程中类单晶的出现,不仅可以保证铸锭提纯区金属杂质成分均匀,而且可以进一步促进杂质向铸锭顶部富集,铸锭顶部的铁杂质含量高达0.101%。因此,利用电子束诱导类单晶生长成为可能,促进金属杂质的去除,为循环硅料的再生提供途径。     

电解金属锰生产过程除镁的研究

对电解法炼锰生产过程中的硫酸锰电解液除镁进行研究。先将部分硫酸锰电解液除去重金属杂质,然后对原始电解液和除重金属后的电解液分别使用重结晶法和氟化沉淀法进行除镁对比试验。结果表明,先用硫化沉淀法除重金属,再用氟化沉淀法除镁,除镁效果最佳,除镁率达到92.74%。     

Thermodynamics of Interstitial Impurities Removal from Refractory Metals

Abstract

The applied thermodynamic aspects of removing hydrogen, nitrogen, oxygen, carbon, and silicon from vanadium, niobium and tantalum metals by pyrovacuum treatments are considered in this paper. Two major processes operate in refining by pyrovacuum treatment. One is distillation and the other is degassing. Distillation is mainly used to remove substitutional impurities that are either already present in the metal or have been added for removing any interstitial impurity. The success is determined by the partial pressure of the impurity element as well as by the difference in partial pressures of the impurity and the metal. The maximum rate of vaporization of impurity can then be estimated using the free evaporation equation. Interstitial impurities, particularly the gases hydrogen, nitrogen and oxygen, are removed by degassing. Thermodynamics of classical degassing, which is essentially the reverse of absorption, is described usefully by the pressure-composition isotherms. This is applicable mainly for the removal of hydrogen and nitrogen. The removal of oxygen, known as deoxidation, occurs by a more complex mechanism that involves the formation and evaporation of metal suboxides. Depending on the suboxide species responsible for deoxidation, the process is known as sacrificial deoxidation, carbon deoxidation, silicon deoxidation, or aluminium deoxidation. The applicability of these different processes to a particular metal, M is determined by the thermodynamic properties of the relevant M-Q, M-C-O, M-Si-O, and M-AI-0 system. It is shown in this paper that all the four processes are applicable to niobium and tantalum where as only aluminium deoxidation is useful for vanadium. For the removal of carbon and silicon also, the relevant deoxidation process can be used.     

负载纳米ZnS阳离子树脂选择性去除浓锌溶液中的痕量级Cu2+和Cd2+

通过将ZnS纳米粒子负载在阳离子树脂D001中制备负载纳米ZnS阳离子树脂吸附剂,即ZnS@D001,吸附湿法冶金锌浸出液中共存杂质金属离子（如Cu2+和Cd2+）。在10 g/L Zn2+的合成溶液中实现了对Cu2+的高度优先吸附,而对Cd2+没有任何吸附效果。吸附后的ZnS@D001树脂可以被1 mol/L HNO3有效解吸,然后再次负载ZnS。同时利用含有Cu2+和Cd2+的Zn2+溶液进行固定床柱吸附测试。经过吸附处理后,可以有效去除溶液中的铜杂质,纳米ZnS树脂可作为锌冶炼行业深度净化锌液的潜在功能材料。     

Thermodynamics of Interstitial Impurities Removal from Refractory Metals

The applied thermodynamic aspects of removing hydrogen, nitrogen, oxygen, carbon, and silicon from vanadium, niobium and tantalum metals by pyrovacuum treatments are considered in this paper. Two major processes operate in refining by pyrovacuum treatment. One is distillation and the other is degassing. Distillation is mainly used to remove substitutional impurities that are either already present in the metal or have been added for removing any interstitial impurity. The success is determined by the partial pressure of the impurity element as well as by the difference in partial pressures of the impurity and the metal. The maximum rate of vaporization of impurity can then be estimated using the free evaporation equation. Interstitial impurities, particularly the gases hydrogen, nitrogen and oxygen, are removed by degassing. Thermodynamics of classical degassing, which is essentially the reverse of absorption, is described usefully by the pressure-composition isotherms. This is applicable mainly for the removal of hydrogen and nitrogen. The removal of oxygen, known as deoxidation, occurs by a more complex mechanism that involves the formation and evaporation of metal suboxides. Depending on the suboxide species responsible for deoxidation, the process is known as sacrificial deoxidation, carbon deoxidation, silicon deoxidation, or aluminium deoxidation. The applicability of these different processes to a particular metal, M is determined by the thermodynamic properties of the relevant M–O, M–C–O, M–Si–O, and M–Al–O system. It is shown in this paper that all the four processes are applicable to niobium and tantalum where as only aluminium deoxidation is useful for vanadium. For the removal of carbon and silicon also, the relevant deoxidation process can be used.     

Purification of Vanadium by External Gettering

Vanadium metal has been purified with respect to carbon, oxygen and nitrogen by allowing these impurities to diffuse to and react with a surface layer rich in titanium. The nitrogen concentration was reduced from 100 ppm to less than 1 ppm, the carbon concentration was reduced from 240 ppm to less than 2 ppm and the oxygen concentration was reduced from 290 ppm to 6 ppm. The resistance ratio was increased from 52 to more than 685, a value that would indicate a total interstitial impurity concentration of 11 ppm. The diamond pyramid hardness was between 44 and 50 after purification. The internal friction peaks due to these interstitial solutes had almost completely disappeared in the purified metal. The purification can be done at any temperature at which the interstitial solutes are able to diffuse rapidly enough. Both 1000 and 1200 °C were found to be satisfactory with somewhat higher purity obtained at 1000 °C. This method is quite versatile and can be applied to specimens more than one cm thick if sufficient time is allowed for diffusion.