Sugar is extracted from sugar beets through a process involving slicing, diffusion, juice extraction, and refinement. Here's a breakdown of the steps:
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Slicing: Sugar beets are first washed and then sliced into thin strips called cossettes. This increases the surface area for efficient sugar extraction.
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Diffusion: The cossettes are then immersed in hot water in a diffuser. The hot water draws out the sugar from the beet slices, creating a sugary juice. This process leverages the principle of osmosis, where sugar moves from an area of high concentration (inside the beet) to an area of low concentration (the hot water).
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Juice Extraction: After diffusion, a screw press may be used to extract any remaining juice from the beet pulp. This maximizes the sugar yield.
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Juice Purification: The juice obtained contains impurities. These are removed through a process called liming and carbonation. Lime (calcium oxide) is added to the juice, precipitating out many impurities. Carbon dioxide is then bubbled through the juice to remove excess lime.
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Evaporation: The purified juice is concentrated through evaporation, removing excess water and creating a thick syrup.
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Crystallization: The syrup is then boiled in vacuum pans under controlled conditions to encourage sugar crystals to form.
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Centrifugation: The mixture of sugar crystals and remaining syrup (molasses) is spun in centrifuges to separate the crystals.
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Drying and Cooling: The sugar crystals are then dried and cooled.
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Optional Refining: The raw sugar crystals may undergo further refining to remove any remaining color or impurities, resulting in white granulated sugar.
The beet pulp remaining after sugar extraction can be dried and sold as animal feed.
