Question

# What is the role of animal charcoal and slaked lime in the manufacture of sugar from sugarcane?

Hint: As we know slaked lime also called Calcium hydroxide which is an inorganic compound and whose chemical formula is $Ca{{(OH)}_{2}}$. Where animal charcoal which is a fine charcoal made by calcining bones.

Manufacturing of sugar consist of few steps they are: -
Extraction of juice from the source.
Clarification of the juice.
Concentrate the juice and crystallized to obtain the crystals of sugar
The process of separating and drying of sugar crystals
As the process starts from extraction the juice is extracted from the sugarcane in the mill and the solution obtained is treated as cane-juice. The clarification of the raw juice contains sucrose and in small quantities of glucose, fructose, vegetable proteins, etc. if the juice is remaining untreated for some time then it begins to ferment, therefore to avoid this fermentation two main processes are done.
Sulphitation: Adding milk lime or slaked lime with sulphur dioxide.
Carbonation: Adding of slaked lime with carbon dioxide

Carbon dioxide is passed through the defecated juice, which contains untreated lime and calcium sucrose (carbonation). This removes the excess of lime as calcium carbonate and decomposes calcium sucrose. Defecated juice is treated with sulphur dioxide (Sulphitation). It prevents formation of brown mass by oxidation.
Where bone char or animal charcoal works as a decolorizing filter, which allows sugar to achieve its desirable white colour.
The concentration process of the juice works, where the concentration is done on different levels. After which the clear syrup juice is boiled in a vacuum pan till the formation of sugar crystals is formed and then the crystallizing tank allows to cool slowly.
After the sugar crystals are formed the separation process begins.

Note: Slaked lime is also called as milk lime or lime water or carbon hydroxide, the name given to a compound has been different is different place, but the formula is same $Ca{{(OH)}_{2}}$.Whereas animal charcoal is also referred to bone char.