The main aim of dense medium separation is pre-concentration:
- Tailings rejection
- Reduces the unnecessary comminution of waste material and all of the costs that are associated with it
- Upgrade of mill feed
- Optimisation of plant capacity
Heavy liquid separation (HLS)
GSL offers heavy liquid separation (HLS) using sodium polytungstate (SPT), sometimes referred to as sodium metatungstate. The test work can be used to determine the susceptibility of ore to dense media separation. It will also provide crucial information on the density parameters of the ore as well as key information that is required to implement density separation for pre-concentration:
- The optimum density for separation
- The tailings rejection that can be achieved whilst maintaining recovery
- The grade that can be achieved
Most HLS test programs involve repeated tests at multiple densities to determine the optimum SG for separation. Often it may be part of a larger test program, particularly in early phase feasibility studies. At GSL we have a HLS separation tank which allows us to efficiently produce pre-concentrated material as part of a comprehensive test program.
For extensive HLS test programs, GSL has developed a method using mineralogy to accurately predict the HLS response of an ore. This method should be calibrated against HLS test work on the same ore.