By-Products

These are defined as “products recovered from material discarded in a main
process, or from the production of some major products, where the material value is to be
considered at the time of severance from the main product.” Thus by-products emerges as a
result of processing operation of another product or they are produced from the scrap or waste
of materials of a process. In short a by-product is a secondary or subsidiary product which
emanates as a result of manufacture of the main product. Examples of by-products are
molasses in the manufacture of sugar, tar, ammonia and benzole obtained on carbonisation of
coal and glycerine obtained in the manufacture of soap.