Environmental and climate protection are key issues at Aurubis. The world’s largest copper recycler and leading provider of nonferrous metals runs a group-wide continuous improvement program in these areas. This includes the plant at Olen, Belgium, where roughly 580 employees produce anodes, cathodes, cast wire rod and special wire. The plant began to get its systems in shape for ISO 14001 as far back as 1998. Today, all the environmental programs in Olen are certified, with heavy investments being made in air emission controls and wastewater treatment processes.
The company was also searching for a (literally) clean solution for neutralizing the process water. Under difficult conditions, measurement points in three reactors and the outlet filter monitor the pH value, a relevant parameter for protecting surrounding waters. Apart from the correspondingly high maintenance and calibration effort, interruptions occurred on a regular basis, and because of moisture, the cabling had to be replaced time and time again.
To improve measurement stability, the company installed pH sensors with Memosens technology from Endress+Hauser. Since the measurement signal is digitized in the sensor and sent to the transmitter inductively, the measurements are impervious to undesired influences caused by moisture or corrosion.
The technology furthermore permits precalibration in the lab, thus making it possible to quickly replace the sensors during operation. The highly precise and stable pH measurements have not only reduced system downtime at the Aurubis location in Olen, but have also cut down on the use of caustic soda needed to regulate the pH value, thus improving cost efficiency.