Refining is a series of stages to purify and remove colour from the raw product. One of those stages is called carbonatation. Carbonatation involves mixing sugar liquor and milk of lime, then bubbling CO2 gas through the mixture.
Fig 1. Carb Tank
The bubbling CO2 gas causes a chemical reaction, converting the lime into calcium carbonate (CaCO3) precipitate, which traps impurities floating in the solution. The slurry solution is then passed through a sequence of cloth filters leaving behind a mud we call filter cake which is sold in bulk to a fertilising manufacturer.
Fig 2. Cloth-filter presses
Fig 3. Filter cake is trucked in bulk to a fertilising business