Hydrometallurgical Process and Economic Evaluation for Recovery of Zinc and Manganese from Spent Alkaline Batteries

Abstract

An innovative, efficient, and economically viable process for the recycling of spent alkaline batteries is presented herein. The developed process allows for the selective recovery of Zn and Mn metals present in alkaline batteries. The hydrometallurgical process consists of a physical pre-treatment step for separating out the metal powder containing Zn and Mn, followed by a chemical treatment step for the recovery of these metals. Sulfuric acid was used for the first leaching process to dissolve Zn(II) and Mn(II) into the leachate. After purification, Mn was recovered in the form of MnO2, and Zn in its metal form. Furthermore, during the second sulfuric acid leaching, Na2S2O5 was added for the conversion of Mn(IV) to Mn(II) (soluble in the leachate), allowing Mn to be recovered as MnCO3. Masses of 162 kg of Zn metal and 215 kg of Mn (both in the form of MnO2 and MnCO3) were recovered from one ton of spent alkaline batteries. The direct operating costs (chemicals, labor operation, utilities, energy) and indirect costs (amortization, interest payment) required for a plant treating 8 tons of spent batteries per day was calculated to be $CAD 726 and $CAD 534 per ton, respectively, while the total revenue from the sale of the metals was calculated at $CAD 1359.6 per ton of spent batteries. The development of this type of cost-effective industrial process is necessary for a circular economy, as it contributes to addressing environment- and energy-related issues, and creates opportunities for the economic utilization of metals.

Recovery and Recycling of Valuable Metals

“…Seventeen articles have been published in this Special Issue of Metals, encompassing the fields of mineral processing and extractive metallurgy [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. These articles cover a wide range of topics in the field and provide some ideas for active researchers who are working on the production of valuable metals from primary and secondary resources.…”

A Review on Chemical versus Microbial Leaching of Electronic Wastes with Emphasis on Base Metals Dissolution

“…The whole flow sheet of the work is shown in Figure 2. A similar investigation was conducted for Zn and Mn leaching and recovery from spent alkaline batteries using sulfuric acid [74]. In yet another study, an alkaline glycine leaching was considered for Cd recovery from spent Ni-Cd battery.…”

Extraction and separation of potassium, zinc and manganese issued from spent alkaline batteries by a three‐unit hydrometallurgical process

“…The low extraction of Mn using only acids like H 2 SO 4 is because the chemical species of Mn with oxidation state of Mn (II) and Mn (III) will be oxidized to MnO 2 (Mn(IV)) which is insoluble in acid solution. 16,17 At the best of our knowledge, only one study reports a high extraction of both Zn and Mn (100 (wt. %) and 82 (wt.…”