Electroflotation extraction of a heavy metal hydroxide mixture from a multi-component solution

Considerable attention is paid to the issues of wastewater treatment in the metallurgical industry. Electrochemical wastes are certainly considered as the most dangerous in terms of negative impact on the environment and humans. The high content of heavy metals and extreme pH values make it impossible to discharge such wastewater without deep purification treatment. The electroflotation method for extraction of metals from multi-component systems is considered as the most efficient. As part of the work done, the influence of addition of flocculants and surfactants, as well as the background electrolyte, on the efficiency of extracting a mixture of metals Fe2+, Ni2+, Zn2+, Co2+, Cu2+, was assessed. It has been established that systems with electrolyte based on sodium sulfate have higher stability due to changes in the surface layer and the “dispersed particle – gas bubble” interface, while addition of OS-20B surfactant leads to inhibition of the electroflotation process and decrease of the efficiency of heavy metals extraction. A similar effect was observed for a system with a background electrolyte based on sodium chloride and the addition of ALM-10 surfactant. Addition of flocculants did not have a significant effect on the efficiency of electroflotation purification and was considered as not advisable. Based on the obtained results, a conceptual scheme for the process of wastewater purification treatment from heavy metal ions using the electroflotation method is proposed.