物質フロー分析及び熱力学的解析に基づくレアメタルリサイクル性評価

本研究主要对各种稀有金属的可回收性进行热力学评价。总体而言，考虑了对报废(EoL)镍、钴、镍钴合金、钛、锌和硅产品的回收。在回收过程中，EoL产品中的合金元素通常被视为杂质元素，本研究采用热力学方法定量评价了它们的可去除性/可控性。在2014年(H.26)开展了EoL镍基和钴基高温合金重熔工艺精炼的热力学评价后，通过金属/渣/气平衡实验测定了CaO-Al_2O_3-SiO_2渣中NiO和CoO的活度系数，为重熔工艺控制Ni-Co基溶剂合金提供了基本的热力学信息。控制CaO-Al_2O_3-SiO_2渣的碱度接近1，有利于去除EoL高温合金重熔过程中的含铁，减少镍、钴的氧化损失。在此基础上对CaO-Al_2O_3-SiO_2渣系Ni-Co-Fe合金成分的可控性进行了评价。用热力学方法评价了熔渣处理和定向凝固工艺对硅的细化效果。对亚氧化物蒸发脱除EoL钛中铝和钒的热力学进行了评价。在对锌在H.26中精炼的热力学评价的基础上，实验测定了铁和铅在氯化炉渣和锌之间的分配。

This study mainly focused on the thermodynamic evaluation on the recyclability of various rare metals. Totally, recycling of end-of-life (EoL) nickel, cobalt, nickel-cobalt based alloy, titanium, zinc, and silicon products was considered. During the recycling, the alloying elements contained in EoL products are always treated as impurity elements, and the removability/controllability of them was quantitatively evaluated using thermodyanmic method in present study.1. Following the thermodynamic evaluation on refinability of EoL Ni- and Co-based superalloys by remelting process carried out in 2014 (H. 26), the activity coefficients of NiO and CoO in CaO-Al2O3-SiO2 slag were measured by metal/slag/gas equilibrium experiments to provide fundamental thermodynamic information for the control of Ni-Co-based solvent alloy using remelting process. Controlling the basicity of CaO-Al2O3-SiO2 slag close to unity is found helpful to remove the contained iron and reduce the oxidation losses of nickel and cobalt during remelting of EoL superalloys. The controllability of Ni-Co-Fe alloy composition using CaO-Al2O3-SiO2 slag was evaluated based on present results.2. The refinability of silicon using slag treatment and directional solidification processes was evaluated by thermodynamic method.3. The removability of aluminum and vanadium from EoL titanium by evaporation of sub-oxides was thermodynamic evaluated.4. Following the thermodynamic evaluation on the refinability of EoL zinc in H.26, the distribution of iron and lead between chloride slag and zinc was experimentally measured.