Work

An experimental design-driven hydrometallurgical process for selenium recovery from copper anode slime with optimization of nitric acid leaching and sulfide precipitation

Year: 2026

Type: article

Abstract: This study establishes an optimized hydrometallurgical process for selenium recovery from Sarcheshmeh copper anode slime. The raw copper anode slime contained 9.27 wt.% selenium, along with a significant barite-rich gangue phase (~ 65 wt.%). Preliminary physical separation methods failed to reject this barite effectively, directing the focus toward direct acid leaching. Preliminary leaching confirmed high selenium solubility (> 99%) in nitric acid. To refine the process economically, critical parameters-nitric acid concentration, temperature, pulp density, and time-were optimized using a Central Composite Design within a Response Surface Methodology framework. The derived statistical model exhibited excellent predictive capability. The optimum leaching conditions were identified as 3.75 M HNO₃, 90 °C, a pulp density of 6.25%, and a 90-min duration, resulting in a 97.45% selenium extraction yield. Selenium was subsequently recovered from the resulting leachate via sodium sulfide precipitation. This secondary step was also optimized, with maximum selenium precipitation (97.80%) achieved at pH 2.5 using a 10 g/L Na₂S dose. The integrated process demonstrates an efficient and statistically-guided route for high-yield selenium recovery from complex anode slime matrices.

Source: Scientific Reports

DOI: 10.1038/s41598-026-69780-0

Authors: Hassan Zare Tavakoli, Fazel Zahakifar

Institutions: Atomic Energy Organization of Iran, Nuclear Science and Technology Research Institute

Language: English

Topic: Extraction and Separation Processes

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Clean water and sanitation

Open Access status: gold

Estimated APC paid: $2,690