November 26, 2024

Optimising Copper Electrorefining: The importance of quality instrumentation

In copper electrorefining, performance optimisation is a must for maximum current efficiency, lower costs, and ensuring that cathode quality remains within specification. One of the most effective ways to accomplish such a goal is with state-of-the-art instrumentation.

Real-time monitoring of key process parameters, such as copper concentration, shorts in cells, and cell voltages, empowers plant managers, process engineers/metallurgists, and operators. This control allows for informed adjustments that keep the electrorefining process running smoothly in the tankhouse, instilling confidence in the decision-making process.

Modern technologies like wireless sensors also offer enhanced control, allowing issues to be addressed proactively rather than reactively.

This article will explore the role of instrumentation in copper tankhouses, highlighting advanced tools and their practical applications. We’ll also look at Mipac’s specialised products — CellView®, ShortMeter®, and Copper Monitor® — as examples of how plant managers and process engineers can harness measurement technology to maximise current efficiency.

Understanding Key Process Parameters in Electrorefining

Copper electrorefining relies on the precise control of several critical parameters, including temperature, copper concentration, and cell voltages. Variations in these can significantly impact cathode quality and current efficiency. Monitoring each of these parameters accurately is essential for maintaining optimal operating conditions.

Temperature

The electrolyte temperature in a tankhouse cell impacts current efficiency, cathode quality and silver losses to cathode. Excessively high temperatures can increase evaporation rates, resulting in excessive heating costs.

Higher temperatures also cause silver to become more soluble in electrolytes, causing more to plate out in the cathode, reducing the cathode purity and the precious metal value in anode slimes.

Furthermore, glue/gelatine in electrolytes decomposes faster and may lead to glue depletion and poor rounding of nodules. Conversely, lower temperatures reduce copper ion solubility and increase the likelihood of anode passivation. Lower temperatures also cause lower electrolyte conductivity, which increases cell voltage and power costs.

Real-time temperature monitoring allows operators to maintain an optimal range, which reduces energy consumption and ensures that cathode quality remains within specification.

Copper Concentration

Keeping copper concentration in electrolytes at optimal levels is vital to maximising current efficiency. Copper must always be available at the cathode surface for deposition at levels far in excess of impurities such as arsenic, bismuth and antimony. If copper concentration drops below critical levels, impurities can plate out onto the cathode, causing product quality issues, and arsine gas generation can occur. Arsine gas is a toxic, odourless, invisible gas that can be fatal if inhaled, even at a parts per million concentration. Excessively high copper concentrations cause higher cell voltages, increasing power costs.

Cell Voltage

Cell voltage monitoring is an integral part of modern tankhouses to monitor short circuits between anodes and cathodes. It assists in locating the sections or cells with lower than average voltage, indicating the presence of shorts. Cell voltage trending can also indicate process issues in electrorefining plants, such as abnormal temperature, reagent addition or electrolyte flow events.

Historical trends can be used to confirm causes of cathode quality issues that are not evident until cathode harvesting, and live monitoring is also done to look for similar voltage trends between cells, sections and circuits.

Mipac’s Measurement Solutions for Copper Electrorefining

Mipac offers a suite of products specifically designed to optimise copper tankhouse operations.

Our tools — CellView®, ShortMeter®, and Copper Monitor® — each play a unique role in measuring and managing key parameters, helping managers and process engineers to maximise current efficiency and maintain quality cathode production.

CellView®

CellView® provides real-time monitoring of individual cell voltages across the electrorefining tankhouse. Abnormal cell voltages can indicate issues such as short circuits, electrode misalignment, anode passivation, reagent issues or electrolyte quality, all of which can impact cathode quality.

With CellView®, metallurgists gain a comprehensive view of cell voltages in every cell, allowing for quick identification and correction of cell voltage anomalies. This improves current efficiency, reduces power consumption, and allows for efficient use of shorts correction labour.

ShortMeter®

Short circuits are a dominant cause of low current efficiency in copper electrorefining but can also lead to other process issues and increased maintenance requirements. Mipac’s ShortMeter® is designed to detect and alert operators to short circuits and dead plates at their exact location above the cell.

By identifying short circuits at their exact cell location, ShortMeter® minimises their impact on the electrorefining process as they can be removed promptly, enhancing the efficiency and productivity of the tankhouse.

Copper Monitor®

Our Copper Monitor® is designed to provide live measurements of copper concentration in the electrolyte. Controlling copper concentration in areas such as the liberators and maintaining stability is crucial in maximising the current efficiency in the tankhouse and ensuring target cathode quality grade.

With real-time copper concentration data, Copper Monitor® allows engineers to maintain a stable process (e.g. liberator plants controlling output concentration) and automate sample taking. This can not only ensure that there is no copper depletion in electrowinning cells and reduce labour costs but also ensure consistent quality of the cathode product.

Benefits for Operations Managers in Copper Electrorefining Tankhouses

The use of advanced measurement instrumentation offers several advantages for technical and operations managers in copper tankhouse operations:

Improved Efficiency

Managers can significantly improve current efficiency by maintaining key parameters within optimal ranges. Consistent monitoring and stable, reliable control reduces energy consumption and maximises cathode yield.

Reduced Downtime

Real-time monitoring enables proactive maintenance, reducing the risk of unexpected breakdowns. For instance, early detection of short circuits or abnormal temperature and cell voltage fluctuations can prompt timely intervention, preventing minor issues from escalating into significant problems and minimising unplanned downtime.

Enhanced Product Quality

Monitoring tools like Mipac’s Copper Monitor® enable precise control over copper concentration in any tankhouse circuit, including liberator plants. By keeping parameters stable, plant engineers can ensure an optimised, stable process, which results in a high level of purity in the copper cathode, meeting customer and industry specifications.

Lower Operational Costs

Advanced measurement tools streamline the copper refining process, reducing anode scrap rate and associated reprocessing costs. When processes such as copper concentration control with sample taking and cell voltage monitoring are automated, labour resources can be more efficiently diverted, lowering operational costs.

Increased Safety

Monitoring critical parameters in real-time enhances plant safety. If undetected, abnormalities in copper concentration can pose safety risks to personnel through arsine gas inhalation and equipment, such as cell fires. By addressing these issues proactively, plant managers can ensure a safer working environment.

Achieve Peak Performance in your Copper Electrorefining Plant

Optimising copper electrorefineries requires a proactive approach to managing process parameters, and advanced measurement instrumentation plays a crucial role in this. By leveraging real-time data and technologies like automated copper concentration control and cell voltage monitoring, technical and operations managers can achieve greater control and stability over the electrorefining process.

Products like Mipac’s CellView®, ShortMeter®, and Copper Monitor® provide specialised solutions to ensure a stable process that can be pushed to safe limits, maximise current efficiency, reduce downtime, and improve cathode quality. Incorporating these tools and techniques into daily operations empowers managers to make data-driven decisions that maximise the performance and profitability of their electrorefining plants.

Contact us today to learn how Mipac’s innovative solutions can enhance your electrorefining process and take your plant’s performance to the next level!