Extraction of rubidium from gold waste: Process optimization

• Published in: Hydrometallurgy Vol. 151; pp. 25 - 32
• Main Authors: Tavakoli Mohammadi, M.R., Javad Koleini, S.M., Javanshir, S., Abolghasemi, H., Abdollahy, M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2015
• Subjects: Acid washing; Charge coupled devices; Gold; Gold waste; Hydrometallurgy; Leaching; Optimization; Rubidium; Salt roasting; Washing; Wastes; Water leaching; Water leaching; Salt roasting; Gold waste; Rubidium; Acid washing
• ISSN: 0304-386X; 1879-1158
• DOI: 10.1016/j.hydromet.2014.10.016

The extraction of rubidium from gold waste from the Mouteh processing plant in Iran by a three-step process (acid washing, followed by salt roasting and water leaching) was optimized. The acid washing step for removal of impurities was found to be optimal at 85°C and 5h, using 5M nitric acid. Factors effecting roasting operation were then optimized by a series of initial experiments, then using response surface methodology (RSM) based on a central composite design (CCD). Rb extraction of 90.95% was obtained with a mass ratio of GW/Na2SO4/CaCl2⋅2H2O of 1.00:0.11:0.45 at 910°C for 30min. Water leaching of the roasted mixture resulted in 97.14% Rb extraction under optimum conditions, viz. a liquid/solid ratio of 1.69 at 58.5°C for 31.4min. The proposed correlations using RSM showed good agreement with the experimental data. •This study aims for extracting rubidium from gold waste using the acid washing-sulfation roasting-water leaching process.•Final extraction efficiency in the optimized process using central composite design (CCD) method is around 88%.•The results of the present work could provide a simple and effective way for the extraction of rubidium from gold waste.