Continuous bio-hydrometallurgical extraction of zinc from a bulk lead-zinc flotation concentrate on a pilot scale. (1st September 2020)

• Record Type: Journal Article
• Authors: Ahmadi, Mosayeb; Hosseini, Mohammad Raouf; Ahmadi, Ali; Foroutan, Abdolrahim
• Is Part Of: Minerals engineering. Volume 156(2020)
• Publication Date: 2020-09-01
• Subjects: Bioleaching -- Continuous -- Flotation -- Large-scale -- Solvent extraction -- Zinc sulfide; Mines and mineral resources -- Periodicals; Ressources minérales -- Périodiques; Mines and mineral resources; Periodicals; Electronic journals; 622
• DOI: 10.1016/j.mineng.2020.106529
• Languages: English
• ISSNs: 0892-6875

Abstract

Highlights: Bulk lead-zinc flotation concentrate was bioleached using thermophilic acidophiles. Bacteria were adapted to 15% pulp concentration using stirred tank reactors. Bioleaching experiments were conducted in a continuous system on a pilot-scale. 83% of zinc was recovered from lead-zinc concentrate after 28 days. 99.9% of zinc was recovered by 30% D2EHPA at pH = 3.5, A/O = 1, after 12 min. Abstract: The high interlock between the fine particles of sphalerite and galena in some parts of the Goushfil mine (Isfahan, Iran) ore has significantly reduced the flotation efficiency. According to the acceptable capability of bioleaching in the recovery of metals from the complex mineralogical resources, the feasibility of zinc extraction from a low-grade (34% Zn) bulk flotation concentrate was investigated. The applied concentrate was processed using a large-scale continuous bioleaching system, including three 50 l stirred bioreactors in series. After 15 days, 83% of zinc was recovered by implementing a mixed culture of moderately thermophile bacteria at pH = 1.8 and 15% solid content. In the next stage, 83% of the accompanying iron impurity was removed from the leachate by jarosite precipitation. Then, about 99.9% of zinc was gained by solvent extraction using 25% saponified D2EHPA at pH = 3.5, O/A = 1 at two steps. Consequently, bioleaching, in combination with bulk flotation, can be successfully applied to recover zinc from the complex lead-zinc ore of the examined deposit.