Sugar Refining

Production of sugar involves a complex mechanical and chemical process that separates sucrose from the sugar canes or beets. It consists roughly of juice extraction, screening, clarification and crystallization by evaporation.

Purification/clarification of the juice generally involves the use of soda ash or caustic soda and lime, their main role being to adjust the pH and alkalinity of the juice and help precipitate impurities. Caustic calcined MgO can be used as an alternative alkali to soda ash or caustic soda in beet sugar manufacture and as partial replacement of lime in cane sugar manufacture with several benefits:

• Soda ash replacement with magnesium oxide in beet sugar plants leads to increased sugar recovery. Reduction in insoluble lime salts, faster crystallization, better separation of the raw sugar and higher non-sugar/water ratios are additional benefits. MgO has higher neutralization capacity and 1 ton would realistically replace 1,5 ton of NaOH or 2 ton of soda ash.
• Partial replacement of lime (30-50%) in cane sugar plants adjusts CaO concentration in the clarified juice below a critical level which leads to a) reduction of scaling in process equipment (magnesium salts are soluble and do not deposit on surfaces), b) juice clarification enhancement (mud has higher density and settles faster, clarifier capacity is increased and filterability is improved), c) pH stabilization during periods of downtime