Digitalizing the electrowinning process and efficiency in copper production: The power of WirelessHART® sensors

Two of the primary factors affecting the reliability and production in the Electrowinning process are the Electrolyte level and the residence time of the Rich Electrolyte in each cell. Many existing installations depend on operators to manually monitor and control these variables, leading to suboptimal efficiency in copper production and potentially hazardous conditions. Additionally, the cost of implementing traditional wired sensors for these measurements is often prohibitively expensive due to the need for a large number of sensors, complex wiring, and control system I/O adjustments to withstand a highly corrosive environment. It is also crucial that these sensors do not interfere with the overhead crane operations, which are responsible for the simultaneous harvesting of anodes and cathodes. However, employing battery powered WirelessHART® sensors eliminates the requirement for cabling, facilitating fully digital monitoring and control of these critical variables.

Inadequate control of the electrolyte level can cause copper deposits to form too high on the cathodes, risking significant damage to the stripping machine at high electrolyte levels. Damaged cathodes must be either repaired or, if irreparable, downgraded in quality and sold at a lower price. The market value difference between a Type A (optimal) and a Type R (rejected) cathode is approximately 20%. The measurement of the level is further complicated by the use of Polypropylene spheres or gas extraction bells to mitigate acid cloud formation around the cells.

An easily installable and reliable solution to accurately measure and control the electrolyte level is the use of guided wave radar level transmitters, which transmit a wireless signal to the supervisory system. These transmitters have a flexible stainless-steel probe inserted into the electrolyte along the cell's side wall, designed to not interfere with cell operations, and offer an accuracy of 3mm for electrolyte level measurement. The transmitter’s electronics are mounted on a simple bracket clamped to the edge of the cell.

Measuring the flow of Rich Electrolyte into the cell allows for calculating the electrolyte's residence time, which is then used to optimize the cathodes' harvest time and, consequently, energy consumption—a significant input for such installations. Utilizing an integral conditioning orifice plate with a DP WirelessHART® transmitter enables relatively accurate flow measurement with a wireless sensor. Unlike traditional orifice plates that require extensive lengths of straight piping to ensure accurate fluid dynamics and measurement, the Conditioning Orifice plate is designed to streamline and measure differential pressure-based flow with minimal straight piping requirements.

Both wireless transmitters employ the WirelessHART® protocol, offering configurable update rates from 1 second to 120 minutes. Depending on the update rate, battery life can vary significantly, with a 60-second update rate providing up to 9 years of battery life for the level transmitter and over 10 years for the DP transmitter. An online power module life estimator is available to calculate the trade-off between battery life and update rate.

The WirelessHART® network uses a self-organizing mesh network topology, significantly extending coverage as more devices are added. This is because devices can relay messages through adjacent devices rather than communicating directly with the gateway, allowing signals to "hop" to the gateway. The network supports a considerable number of devices, with current technology enabling encrypted communication with up to 400 devices per gateway, depending on device types and update rates.

These solutions have been implemented globally, leading to increased production rates and cost savings, with a return on investment achieved in less than 12 months. Moreover, the WirelessHART® infrastructure supports additional measurements, including temperature, gas detection, and safety monitoring, with more information on these and other WirelessHART®-enabled solutions available online here.

Emerson is at the forefront of providing innovative measurement instrumentation solutions applicable across the entire mining process. We understand the challenges faced by mining operators in today's industry—ranging from reducing emissions and water consumption to improving energy efficiency, sustainability, and safety. To address these challenges and share our insights, Emerson has developed both an eBook and a YouTube series that feature proven solutions utilized by real customers in the field. These resources not only demonstrate our advanced technology but also empower mining companies to optimize their processes. Learn more about our cutting-edge solutions and take the first step towards transforming your mining operations by exploring our eBook and YouTube series.

For more information visit Emerson.

Read the article online at: https://www.globalminingreview.com/special-reports/09052024/digitalising-the-electrowinning-process-and-efficiency-in-copper-production-the-power-of-wirelesshart-sensors/