Electrochemical Process Engineering in Biohydrometallurgical Metal Recovery from Mineral Sulfides

Abstract

Primary copper sulfides are recalcitrant to bioleaching, probably due to semi-conductivity or passivation effects which result in slow dissolution kinetics. The mineral dissolution strongly depends on redox reactions and, consequently, electrochemical techniques are recommendable for analyzing and processing of redox-active minerals. For this reason we installed a three electrode system into a conventional bioreactor. Electrolytic bioleaching was applied to a copper concentrate from black shale ore. First results verified the operational capability of ferric iron reduction during electrochemical leaching and that bioleaching is not hindered by the physical presence of the electrochemical setup. Although the working electrode was able to reduce ferric iron and to regenerate it as electron supply for ferrous iron oxidizing microorganisms, the electron input into the bioleaching process has to be further increased to keep up with fast biocatalytical iron oxidation.

Development of Electrochemical Dissolution Method for Nickel Sulfide-Metal Alloy with Cathodic Nickel-Copper Precipitate Formation

“…Alloys based on nickel are used extensively in industry. In particular NiCu alloy exhibiting good ductility, high hardness, and corrosion resistance [1][2][3] is an important structural material used in powder generation [4,5], electrical engineering [6], and other industries.…”

“…The main phases are nickel, copper, iron sulfides with inclusions of metal phase represented by the corresponding metal [1,2]. Nickel extraction from matte may be accomplished by various pyrometallurgical and hydrometallurgical regimes [3][4][5][6]. A new alternative method of electrochemical processing of sulfide materials developed in IMET UrO RAN by a collective of authors [7,8] is electrolysis of granulated copper-nickel matte with separation of copper at the cathode.…”

Electrochemistry of Sulfides: Process and Environmental Aspects

“…Currently, for the processing of low-grade sulfide ores and technogenic mineral resources (overburden, concentration tailings, and smelter slags), heap and bioleaching methods are increasingly being used [11]. The electrochemical properties of sulfides have a decisive influence on the leaching kinetics, the concentration of non-ferrous metals in pregnant solutions, and recovery [12][13][14][15][16]. It should be noted that the utilization of operando/in situ techniques, e.g., X-ray absorption and Raman spectroscopy, can more accurately track the phase, composition, local atomic coordination of sulfides during electrochemistry process.…”

“…In addition to process engineering challenges, the environmental aspect should also be taken into consideration (Figure 1). pregnant solutions, and recovery [12][13][14][15][16]. It should be noted that the utilization o operando/in situ techniques, e.g., X-ray absorption and Raman spectroscopy, can mor accurately track the phase, composition, local atomic coordination of sulfides durin electrochemistry process.…”