1. Raw Sugar Preparation:
- Raw sugar, which is typically brown and unprocessed, is received from sugar mills.
- It may undergo screening and cleaning to remove impurities and debris.
- The raw sugar is then mixed with water to create a syrup called "liquor."
2. Clarification and Filtration:
- The sugar liquor is heated and treated with chemicals, such as lime and phosphoric acid, to remove impurities and suspended matter.
- This process, known as clarification, allows the impurities to settle as sediments.
- The clarified liquor is then filtered to remove any remaining solids.
3. Evaporation:
- The clarified liquor undergoes evaporation to remove water and concentrate the sugar content.
- Multiple evaporators are used to boil the liquor under vacuum conditions, allowing the water to evaporate at lower temperatures to preserve the sugar's quality.
4. Crystallization:
- The concentrated liquor, known as "syrup," is cooled and seeded with sugar crystals to induce crystallization.
- The syrup is agitated in crystallizers to facilitate crystal growth and the formation of sugar crystals.
5. Centrifugation:
- The crystallized sugar mixture is subjected to centrifugation, a process that separates the crystals from the remaining syrup.
- The centrifuges spin rapidly, forcing the sugar crystals to adhere to the basket while the syrup is expelled through openings in the basket.
6. Drying and Cooling:
- The raw sugar crystals obtained from centrifugation are washed with water and then dried using hot air to remove any residual moisture.
- The dried crystals are cooled to room temperature to prevent clumping and ensure proper handling.
7. Screening and Packaging:
- The dried and cooled sugar crystals are passed through screens to separate them based on size and uniformity.
- The refined sugar crystals are then packaged into bags, containers, or bulk storage silos for distribution to consumers and industries.
The sugar refining process aims to produce refined sugar with a consistent quality in terms of color, purity, crystal size, and sweetness. It involves various stages of purification, concentration, crystallization, and drying to transform raw sugar into the refined sugar we commonly use in our daily lives.