White Paper

More Gold from Slimes

White Paper

White Paper on Higher Productivity in Wet Chlorination

At a Rio Tinto copper refinery, development of processes at the precious metals plant has led to increased production of gold from copper anode slimes. This white paper examines the role in-line oxidation reduction potential (ORP) sensors can play in increasing gold recovery.

The use of continuous monitoring of in-line oxidation reduction potential enabled operations to determine the critical end-point of a leach reaction resulting in reduced use of costly reagents, increased yield and improved efficiency.

Discover in this white paper:

  • The importance of ORP measurements during chlorination
  • How METTLER TOLEDO in-line sensors enhance productivity and reduce the use of reagents
  • Predictive diagnostic tools for proactive sensor maintenance
  • Digitized sensor signals that are unaffected by moisture, electrical interference or long cable runs
     
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ORP measurement is important during wet chlorination as it indicates when complete dissolution of the gold content of the slimes has been reached. Therefore, it prevents on the one hand, gold being carried in the raffinate, and on the other, excessive and costly chlorination. The oxidation potential is monitored by in-line ORP measurement. For reliability and accuracy purposes, METTLER TOLEDO ORP measurement systems were installed at Rio Tinto's refinery. 

Higher integrity of the measurement is obtained through the use of METTLER TOLEDO’s Intelligent Sensor Management (ISM) concept. This technology comprises pH / ORP sensors with embedded microprocessors. One advantage of ISM is that the sensor output signal is fully digital and therefore cannot be corrupted by wet electrical connections, electromagnetic interference or long cable runs. Another benefit is that ISM sensors feature predictive diagnostics. Thanks to these, measurement availability can be ensured at all times, as possible measurement problems are detected before they become significant. The sensor will, for instance, indicate how many days of reliable operating life are left so that action can be taken before the sensor fails.