Abstract

Anode slime and tin precipitate as by-products of the electrorefining (ER) of non-standard anodes obtained after experimental smelting of waste electric and electronic equipment (e-waste), in addition to the base and precious metals, contains a significant amount of tin. Due to its presence as inert SnO₂ hydrate (β metastannic acid) and its dissipation between slime and electrolyte, anode slime processing and metals valorization are difficult. This study aimed to investigate conditions under which efficient leaching of metastannic acid could be achieved to facilitate further metals valorization, especially precious metals. The investigation was performed using the by-products obtained from the ER of the non-standard Cu anodes produced by pyrometallurgical processing of e-waste. After detailed characterization of obtained products, the influence of various process parameters like temperature, acid concentration, leaching time, as well as the influence of reducing agent, sulfur compounds, and SnO₂ hydration rate on leaching efficiency was investigated. It was found that efficiency of 99% can be achieved by leaching the desulfurized tin precipitate sample in 6 M HCl at 90 °C for 90 min with the addition of Mg powder. The application of the tin removal process, described in this paper, contributes to efficient material flow management.

Graphic abstract

中文翻译：

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电子废物副产品中偏锡酸的浸出

摘要

阳极泥和锡沉淀物是在对废电气电子设备（电子废物）进行实验冶炼后获得的非标准阳极的电精炼（ER）的副产品，此外还含有贱金属和贵金属。锡。由于其为惰性SnO ₂水合物（β偏锡酸）及其在煤泥和电解质之间的耗散，阳极煤泥加工和金属增值困难。这项研究旨在研究在何种条件下可以实现高效转移偏锡酸，以促进进一步的金属增值，特别是贵金属。使用从电子废物的火法冶金生产的非标准Cu阳极的ER副产物中进行了研究。对获得的产品进行详细表征后，温度，酸浓度，浸出时间等各种工艺参数的影响，以及还原剂，硫化合物和SnO _2的影响研究了水合速率对浸出效率的影响。发现通过添加镁粉在90°C下于6 M HCl中浸出脱硫的锡沉淀样品90分钟可以达到99％的效率。本文所述的除锡工艺的应用有助于有效的物料流管理。

图形摘要