Selective Complexation Leaching of Cobalt Using Histidine in Alkaline Medium

• DOI: 10.20944/preprints202502.1914.v1
• Publication Date: 2025-02-27T05:19:51Z
• Authors: Mengying Li; Qingliang Wang; Weiduo Guo; Xu Zhao; Yaolong Zhang; Xiankun Zhou; Zhiwu Lei; Yahui Zhang

For the extraction of cobalt from cobalt-rich alloy slag, ammonia was considered a lixiviant with limited environmental impact compared to acid lixiviant. However, problems such as large volatilization loss, toxic vapor emissions, and suboptimal process control were encountered during leaching. To address these issues, new method proposed for recovering via selective complexing leaching, where an alkaline histidine solution utilized instead ammonia. A high leaching rate 99% achieved under following conditions: temperature 35℃, histidine/cobalt molar ratio 1.5, pH range 6–11, duration 6 hours, stirring speed 300 rpm. In verification test Cu-Co slag histidine, almost entirely leached, while iron, lead, copper observed be difficult leach. The kinetic analysis revealed that electrons donated Co²⁺ by amino COO⁻ groups in coordination reaction. This confirmed soluble complex, Co(C₆H₉N₃O₂)₂, formed through between Co²⁺.