Processing Sugar From Sugarcane Plant
2 June 2023
Sugar cane is a species of tall, perennial grass that is used for sugar production. The plants are 2–6 m tall with stout, jointed, fibrous stalks that are rich in sucrose, which accumulates in the stalk.
- The cane is crushed through a series of rollers. In order to maximize extraction, water is circulated through the rollers in a countercurrent manner, bringing fresh sugarcane into touch with highly concentrated sugar juice and freshwater into contact with a previously washed cane.
- The sugar juice is flocculated and given a lime treatment to eliminate impurities and dissolve salts.
- To minimize water content and increase the amount of sucrose to roughly 40–50%, sugar juice is boiled and reduced in a succession of multiple-effect evaporators. Thick juice is the name given to the resulting combination.
- After adding nucleation crystals, the sugar juice is poured into three or more vacuum pans, evaporating under vacuum.
- Molasses is optionally preserved by sulfur dioxide treatment. People can consume sugar without sulfur, but the bulk is sulfured and used to feed cattle.
- (Optional) Sugar is either granulated or shaped into loaves after being bleached.
There are various other side processes that are also essential to the proper functionality of a sugar mill. For example, bagasse (the woody cake left after the cane is crushed and sugar extracted) is burned for power production and disposal. Precipitated salts are continuously removed from limed cane juice and usually returned to the fields.