Lime Addition Circuits

Lime Addition Circuits

A lime dosing system typically uses a lime ring main to neutralise tailings or to control the PH of a medium. Typically, lime is continuously pumped around the ring main because it tends to settle and harden when standing still. A Tee-piece is inserted into the line (called a take-off line) and the lime dosing is controlled with a dart valve.

As the dart valve opens the vertical take-off line fills up. When closed the line gravity flushes and therefore does not leaving a pocket in the pipe to solidify. The frequency and volume of lime addition can be set within your PLC to ensure over or under-dosing doesn’t take place.

Design Approach

We work closely with the project house that is responsible for the overall design & performance of the lime dosage system to fully understand the operational requirements in terms of pH control. Issues such as height & position of the ring main relative to the areas of addition are critical as the lime dosage needs to done using gravity.

We analyse the process data taking into account current & future lime addition scenarios. The lime dosage valves are then sized for each dosage point to ensure that the velocity in the ring main is maintained at all times. We use our CFD tools to predict:

  • Lime slurry mixing (homogenous slurry vs separation of particles by size / density)
  • Lime slurry velocity impact on wear & maintenance of the ring main system

More Information

Lime Dosing Valve