PbZn 2020: The 9th International Symposium on Lead and Zinc Processing: Zinc Electrowinning
Sponsored by: The Mining and Materails Processing Institute of Japan, Nonferrous Metals Society of China, GDMB: The Society for Mining, Metallurgy Resourcce and Environmental Technology, Metallurgy & Materials Society of the Canadian Institute of Mining, Metallurgy & Petroleum, TMS Extraction and Processing Division, TMS: Hydrometallurgy and Electrometallurgy Committee, TMS: Process Technology and Modeling Committee, TMS: Pyrometallurgy Committee, TMS: Recycling and Environmental Technologies Committee
Program Organizers: Andreas Siegmund, LanMetCon LLC; Shafiq Alam, University of Saskatchewan; Joseph Grogan, Gopher Resource; Ulrich Kerney, Recylex; Cheng Liu, China Enfi Engineering Corporation; Etsuro Shibata, Tohoku University
Monday 10:45 AM
February 24, 2020
Room: 15B
Location: San Diego Convention Ctr
Session Chair: Georges Houlachi, Hydro-Quebec
10:45 AM
To Polarize or Not to Polarize: Practical Advice on How to Control Zinc Electrodeposition: Michael Moats1; Timothy Hymer2; 1Missouri University of Science and Technology; 2The Doe Run Company
The interaction of impurities and additives on zinc electrodeposition in electrowinning cellhouses are well documented, but generally not well understood. Operators attempt to maximize current efficiency by promoting zinc deposition while simultaneously inhibiting hydrogen evolution. However, the impacts of impurities and additives are often difficult to understand and predict. Thus, plant personnel are left to ponder whether to polarize (add more gelatin) or not to polarize (add less gelatin). This joint paper by an industrial practitioner and academic scholar attempts to describe the interactions between impurities and additives in simple terms and to offer practical advice on how to control cellhouse operations.
11:05 AM
Evaluation of Anodic Oxygen Evolution Activity and Durability of MnOx Electrodeposited Catalysts for Zinc Electrowinning: Sheida Arfania1; Edouard Asselin1; 1The University of British Columbia
Zinc electrowinning is the last step of zinc extraction in which high purity zinc is deposited on the cathode. The electrowinning stage is very energy-intensive and responsible for approximately 80% of the power requirement of a zinc refinery. Improving the energy efficiency and lowering the operating costs are of primary significance to the zinc refining plants. Oxygen evolution overpotential on conventional lead-silver anodes contributes to 25% of the total electrowinning cell potential. Thus, lowering anodic overpotential provides much scope for reducing the energy consumption of the zinc electrowinning process. The present project aims to evaluate the activity and durability of anodically electrodeposited manganese oxide catalysts for electrowinning process. The performance of the novel catalyst is evaluated by long-term galvanostatic polarization and various surface characterization techniques. During the 72-hour galvanostatic operation, approximately 80 mV decrease in anodic potential was observed for the electrodeposited electrodes as compared to conventional anodes.
11:25 AM
Optimizing Additive Ratios in Alkaline Zincate Electrodeposition: Margaret Scott1; Michael Moats1; 1Missouri University of Science and Technology
Alkaline non-cyanide zinc electrogalvanizing is utilized in some plating applications. This study was conducted to evaluate the effects of a commercial carrier, booster and leveler in a strong zinc (37.5 g/L) and alkaline (210 g/L) plating solution. Hull cell plating was used to assess the roles of each additive on the appearance of the zinc deposits produced from synthetic solutions. Bright white deposits were generated with several different combinations of additives at current densities of 170-420 A/m2. The zinc structures were characterized using x-ray diffraction and scanning electron microscopy to understand the microstructure which produced the bright deposits in order to determine the optimal conditions leading to mirror-like deposits.
11:45 AM Cancelled
Current Efficiency Increase in Zinc Electrodeposition at Cajamarquilla Refinery: Juliano Alves de Lima1; Eder Lúcio Martins1; Gian Gonzales1; Tone Filho1; 1Nexa
The Cajamarquilla Zinc Refinery is a Metallurgical Unit belonging to Nexa Resources SA, its production capacity is 335kt of refined zinc. It is an integrated Zinc Refinery that processes Zinc concentrates from the route known as RLE (Roasting - Leaching - Electrowinning). The Electrowinning stage is of fundamental importance because it consumes 80% of all electrical energy and this represents 31% of the entire conversion cost. It also restricts the production capacity of the plant. In the years 2015, 2016 and 2017, there was a significant reduction in the current efficiency of the Electrolysis, impacting the transformation cost and also the production capacity of the Refinery.This work includes research studies, actions taken to restore performance and stability of the process. At present Cajamarquilla's performance in current efficiency is benchmark against the main world competitors. In addition to presenting the main future developments to increase the competitiveness of the unit.