Phase equilibria between slag, Cu–Sn alloy and solid oxide phases, SnO₂ (cassiterite) or SiO₂ (tridymite, cristobalite) are important for oxidizing fire refining of black copper produced during the recycling of copper scrap and waste electrical and electronic equipment. Integrated experimental and thermodynamic modeling study is presented for the Cu–Sn–Si–O chemical system and its sub-systems. Experimental technique involved high-temperature equilibration, followed by rapid quenching and direct measurement of Cu, Sn and Si concentrations in the liquid and solid phases using the electron probe X-ray microanalysis. Experimental results and literature data have been used to develop the thermodynamic database for the system. The database works within the environment of FactSage software, as well as ChemApp, ChemSheet and SimuSage. Combined with other assessments, it can be used to optimize and develop recycling processes using the black copper route.

炉渣、Cu-Sn 合金和固体氧化物相、SnO ₂（锡石）或 SiO ₂之间的相平衡（鳞石英、方石英）对于废铜和废弃电子电器设备回收过程中产生的黑铜的氧化火精炼很重要。对 Cu-Sn-Si-O 化学系统及其子系统进行了集成的实验和热力学建模研究。实验技术包括高温平衡，然后是快速淬火和使用电子探针 X 射线微量分析直接测量液相和固相中的 Cu、Sn 和 Si 浓度。实验结果和文献数据已被用于开发该系统的热力学数据库。该数据库在 FactSage 软件以及 ChemApp、ChemSheet 和 SimuSage 的环境中运行。结合其他评价，