Dissolution Kinetics of Complex Sulfides Using Acidophilic Microorganisms

Abstract

Bioleaching studies were conducted to evaluate a complex sulfide concentrate using an acidophilic microorganism. The leaching kinetics were found to vary based on pulp density, Fe and pH. In addition, the leaching efficiency increased as the Fe(II) concentration increased up to 20 kgÁm À3 , after which it decreased due to an increase in iron precipitation. Furthermore, the bacterial activity was good based on observation of the iron oxidation rate and pH and Eh studies. The leaching efficiencies decreased below 2 and 5% (w/v) in the pH and pulp density studies, respectively. Furthermore, the XRD analyses revealed the presence of various product layers, while the SEM-EDX analyses showed partial contact between different sulfide minerals that resulted in formation of a galvanic couple. The dissolution rate followed a product diffusion model. The diffusivity of Fe(III) for chalcopyrite and sphalerite were calculated.

Microbiological Redox Potential Control to Improve the Efficiency of Chalcopyrite Bioleaching

“…Even though bioleaching is initiated at different Eh levels (500-800 mV (SHE)), rapid microbial Fe 2+ oxidation can increase the Eh levels over 800 mV (SHE) within a few days (Cordoba et al 2008b). Therefore, chalcopyrite bioleaching is highly susceptible to jarosite formation especially at higher pHs (Sasaki et al 2009;Sandström et al 2005), leading to the reaction being controlled by diffusion through product film (Pradhan et al 2010;Abhilash et al 2013Abhilash et al , 2015Stott et al 2000).…”

Development of Bioleaching for Extraction of Metal Values from Low-Grade Ores and Wastes

“…The catalysts contain different metals such as V,Ni,Mo,Co,Fe, etc to increase the efficiency of different production. They lose their physical properties after several cycles of operation and being discarded as wastes [32][33][34][35][36][37][38][39][40][41]. The metal values present in the wastes are very important for the metal industries.…”

Review of Biohydrometallurgical Metals Extraction from Polymetallic Mineral Resources

“…In most laboratory studies, the bioleaching of sulfide minerals or elements associated with them was investigated using known species of iron(II)-and sulfur-oxidising microorganisms in reactors operated at pH 1.5-2 and temperatures in the range of 25-55 °C; the extractions of elements known to leach readily (Cu, Zn, Ni, Co, As) were reported [199][200][201][202][203][204]. The extractions of more refractory metals not necessarily associated with sulfide minerals such as Mo, Re, V and U were reported in only a few studies [205,206].…”