Laboratory and Pilot Scale Tests of a New Potential-Controlled Method of Copper Industrial Electrolysis

Abstract

Copper electrorefining and electrowinning industrial processes are carried out on industrial scale as current-controlled processes practically from the beginning of the commercial exploitation. However, it is the electrode potential which is a driving force of electrochemical process. The copper electrodeposition from industrial electrolytes is in fact a very complex multi-ion process. Consequently, the theoretical analysis of the experimental results should take into account that in concentrated and complex matrix electrolytes migration, convection and diffusion are mass transfer modes. However, there is only very limited number of papers where copper electroreduction from concentrated electrolytes is considered and most of the published theoretical and experimental studies are carried out in diluted electrolytes of relatively simple compositions where only diffusion of copper ions is considered in theoretical analysis. In the present paper some basic aspects of potential-controlled electrolysis of copper in concentrated and industrial electrolytes as a new method of copper electrorefining and electrowinning are presented and discussed. The pilot scale tests results of copper potential-controlled electrolysis are published for the first time. Apart from the possible industrial applications, studies of the electrochemical processes in concentrated electrolytes are very important from the basic research point of view.

Dismantling and electrochemical copper recovery from Waste Printed Circuit Boards in H2SO4–CuSO4–NaCl solutions

“…9a-d after dipping in 4 M NaCl at pH 1. Particles of various shape cover the surface forming a typical layer of electrodeposited copper already reported in the literature (Cocchiara et al, 2017;Fogarasi et al, 2014;Los et al, 2014). In potentiostatic mode (Fig.…”

“…Despite the copper deposition is usually carried out in galvanostatic mode, here, the potentiostatic electrodeposition was also investigated. Indeed, as shown in the literature (Los et al, 2014), it is possible to get high quality deposits through a potential-controlled deposition determining much higher current densities than in current-controlled process.…”

“…Table 4, in which the phases formed in different conditions are summarized, clearly evidences that the purity of the deposit is decaying as the deposition rate is increasing, i.e. when the applied current or potential were increasing ( Aslin et al, 2017;Los et al, 2014). An exception to this trend is represented by the deposit obtained at −0.25 V, which shows the highest purity together with that obtained at −23.8 mA/cm 2 , as also confirmed by the less greenish color of deposits obtained under these conditions (Fig.…”

The time-varying effect of thiourea on the copper electroplating process with industrial copper concentrations

“…The electrolyte used in this paper consistently contains 40 g/L of copper ions, 195 g/L H 2 SO 4 and 0.045 g/L chloride ions, which are typical industrial ER electrolyte concentrations [1]. If TU is added, the concentrations are respectively 0.5 mg/L or 1.0 mg/L and are likewise industrially relevant [18,26,27]. A double walled cell is used as isothermic reactor vessel, set at 20 • C. The solution is deaerated with N 2 before every experiment and a N 2 blanket is applied during the measurements.…”

“…The goal of this paper is to extend the understanding of the timevarying copper deposition in the presence of TU in electrorefining electrolyte containing industrial copper concentrations [1,27].…”