Flow and Concentration Measurement of Liquors in Heap Leach Applications

Flow and Concentration Measurement of Liquors in Heap Leach Applications

Copper oxide ore and other copper-containing minerals are usually stacked into a heap where a strong sulphuric acid leach solution is sprinkled on top of it allowing the acid solution to percolate through the heap of ore. The copper oxides become dissolved and the pregant leach solution (PLS) eventually flows out of the heap into a collection pond.

Volumetric flow as well as concentration measurements of the leach and PLS solution are required for efficient process control. Conventionally used magnetic inductive meters for measuring flow rates on these lines are often sensitive to scaling and corrosion of electrodes and flowtubes result in measurement drift, non-repeatability, increased maintenance, and costly process down-time when they need to be repaired or replaced.

FLEXIM's non-invasive ultrasonic flowmeters and process analyzers are the superior measuring solution for such applications. As the ultrasonic transducers are mounted on the outside of the pipe wall, they are never in direct contact  with the corrosive medium inside. Based on the measurement of the transit-time of the ultrasonic signal travelling through the liquid, the meter is able to determine the volumetric flow rate. Further by monitoring the sonic velocity and correlating it with its internal database, the system accurately determines the concentration of the sulphuric acid.

The measuring system is engineered to withstand the harshest environments. Residing inside rugged stainless steel mounting fixtures, with the transducer cables being housed in steel armored cables and ensuring a long-term stable pipe wall contact with permanent coupling pads, enables the meters to be virtually maintenance free.

FLEXIM's measuring systems FLUXUS and PIOX deliver financial and operational benefits associated with increased production efficiency and up-time, as well as significantly decreased maintenance costs.


  • Combined flow and concentration measurement on PLS and Raffinate lines
  • Installed on the outside of the pipe wall without any process shut-downs
  • Highly cost-effective due to low installation costs and no maintenance requirements - also being independent of pipe dimensions and materials of construction
  • Highly accurate and repeatable measurements over the complete lifecycle - completely drift-free and stable even under the harshest conditions

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