钽表面离子渗氮工艺研究

采用组合的二次回归正交设计方法,针对表面硬度、表面粗糙度,对钽表面离子渗氮工艺参数（气体压力、温度、氢气摩尔分数）进行了优化。根据回归结果和统计分析给出了回归方程。     

Niobium and tantalum recovery from the primary source and from tin slag,an industrial challenge: A review

Niobium (Nb) and Tantalum (Ta) are used to increase materials' mechanical resistance and produce lighter alloys. Worldwide Nb production reached 78 000 t in 2020. The reduced ore offer justifies the recycling of these metals from tin slag, contributing to the circular economy. Nb₂O₅ and Ta₂O₅ extraction either from the primary source or the tin slag is an industrial challenge. Nb and Ta dissolution processes already implemented are fluoride leaching, sulphuric leaching, alkaline leaching, and alkaline roasting. The fluoride process raises environmental concerns about waste control. The sulphuric method can be managed to have higher Nb and Ta extraction in a less aggressive process, if some changes are implemented, such as increasing the number of extraction steps, decreasing the pulp density, or increasing the temperature; however, the efficiency of this methodology must be tested for tin slag. The alkaline method seems to be more selective to Nb and Ta by reactants and temperature control. Despite those well-established Nb and Ta treatments, they must be adapted to recover Nb and Ta from slag. The slag has low Nb and Ta content, while high Si and Ca concentrations exist in the matrix. This paper brings the main methods used to extract the Nb and Ta from the primary resources and an overview of Nb and Ta recovery from the slag. This investigation comes as a tool to guide the development of new methods to recover Nb and Ta from low-grade sources such as tin slag.     

All‐in‐One Theranostic Nanoplatform Based on Hollow TaOx for Chelator‐Free Labeling Imaging,Drug Delivery,and Synergistically Enhanced Radiotherapy

Despite extensive use of radiotherapy in cancer treatment, there has been huge demand to improve its efficacy and accuracy in tumor destruction. To this end, nanoparticle‐based radiosensitizers, particularly those with high‐Z elements, have been explored to enhance radiotherapy. Meanwhile, imaging is an essential tool prior to the individual planning of precise radiotherapy. Here, hollow tantalum oxide (H‐TaOx) nanoshells are prepared using a one‐pot template‐free method and then modified with polyethylene glycol (PEG), yielding H‐TaOx‐PEG nanoshells for imaging‐guided synergistically enhanced radiotherapy. H‐TaOx‐PEG nanoshells show strong intrinsic binding with metal ions such as Fe³⁺ and ^99mTc⁴⁺ upon simple mixing, enabling magnetic resonance imaging and single photon emission computed tomography imaging, respectively, which are able to track in vivo distribution of those nanoshells and locate the tumor. With mesoporous shells and large cavities, those H‐TaOx‐PEG nanoshells show efficient loading of 7‐ethyl‐10‐hydroxycamptothecin (SN‐38), a hydrophobic chemotherapeutic drug. By means of the radiosensitization effect of Ta to deposit X‐ray energy inside tumors, as well as SN‐38‐induced cell cycle arrest into radiation‐sensitive phases, H‐TaOx‐PEG@SN‐38 can offer remarkable synergistic therapeutic outcome in the combined chemoradiotherapy. Without appreciable systemic toxicity, such hollow‐TaOx nanostructure may therefore find promising applications in multimodal imaging and enhanced cancer radiotherapy.     

Evaluation of Neutron Capture Gamma-Ray Spectra in Hafnium and Tantalum

A method has been developed for evaluation of neutron capture γ-ray spectrum. It couples measured intensities of primary and secondary discrete—-ray with a γ-ray cascade model to calculate the unresolved part of the capture spectrum, and adds the discrete part and the unresolved part to obtain the whole spectrum. The cascade model uses the level density formula proposed by Gilbert & Cameron and the Brink & Axel form of El γ-ray profile function with a modification. This method was applied to thermal neutron capture spectra in six hafnium isotopes and ¹⁸¹Ta and was extended also to non-thermal capture spectra in ¹⁸¹Ta for 0.25 and 0.5 MeV neutrons with empirical assumptions. The calculated results were compared with experiments and agreement was good not only in terms of the gross structure, but also in terms of the fine structure which appears at high and low γ-ray energies.     

Evaluation of Photonuclear Reaction Data on Tantalum-181 up to 140MeV

Photonuclear cross sections of ¹⁸¹Ta are evaluated up to an incident photon energy of 140MeV which is the threshold energy for pion production. Re-analyses were performed on the (γ, n) and (γ, 2n) data measured at Saclay and Livermore, and reference data were reconstructed. The absorption cross sections were evaluated with the giant electric dipole resonance (GDR) model below 40MeV. The calculation by the statistical model with preequilibrium correction reproduced the reference data of all the photoneutron cross sections consistently. From 40 to 140 MeV, the quasideuteron model (QDM) was adopted to evaluate photoabsorption cross sections and the results are compared with the measurements. The decaying processes including n, p, d, t, ³He, and α particle emission up to 140MeV were theoretically evaluated by the ALICE-F code.     

钨钽铌粗精矿碱分解试验研究

针对难分解钨钽铌粗精矿的冶炼问题,采用了高压碱分解工艺,成功地实现了钨钽铌精矿中钨难分解的问题。研究针对江西某大型钨、钽铌矿床矿石重选矿泥,经选矿试验获得的钨钽铌粗精矿,探讨了NaOH加入量、Na3PO4·12H2O加入量、液固比、分解温度、分解压力、分解时间对钨分解率的影响。结果表明,NaOH加入量为理论量的1.70倍,Na3PO4·12H2O加入量为理论量的1.26倍,液固比为3,分解温度200℃,分解压力1.5 MPa,分解时间5 h,钨的分解率能达到99.84%,分解渣中WO3含量为0.16%。     

中国首条沸腾氯化法钛白粉生产线通过72h连续试生产

介绍了采用ICP—AES法同时测定钛合金中Ta、Nb、W元素含量的方法。首先确定了仪器部分工作参数的最佳值,其中激发功率1300W、雾化器流量0．7L·min^-1、积分次数2次。然后通过对基体、合金元素以及测定元素光谱间的干扰分析研究,确定了Ta、Nb、W元素最佳分析谱线的位置,依次为240．063、269．706、207．912nm。此外,采用内标法对Nh质量分数大于3％的样品的测试结果进行了校正。试样加标回收试验及精密度试验表明采用上述方法可使回收率在99％～102％之间,相对标准偏差小于2．3％,能够满足日常生产的检测要求。     

废钨渣中钽、铌、钨高效共提新工艺研究

阐述了采用氟盐转型-HF-H2SO4浸出-氟盐氨转化循环利用过程同步提取废钨渣中的钽、铌、钨的新工艺.通过实验确定了最佳工艺条件,在最优条件下可分别获得Ta2O5和Nb2O5含量分别为6.08%和27.29%的钽铌富集渣及WO3含量为26.71%的钨富集渣.两种富集渣均可直接用于工业生产.钽、铌、钨的单程回收率分别达到83.18%、88.33%和77.91%.该方法工艺流程简单,操作条件温和,且由于氟盐可实现循环利用,工艺过程物料消耗低、成本低廉、技术经济性良好.     

钽-铜-不锈钢复合板设备的制造

根据钽材的特性,分析了钽-铜-不锈钢复合板设备的制造难点和控制要点,简述了钽-铜-不锈钢复合板设备相关零部件的加工方法及钽材的焊接注意要点。制造的设备投用后运行正常,满足相关要求。     

Kinetic mechanism of anodic oxidation of tantalum in nitrate melts

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