Process for the production of ethylene for chemical use starting with a hydrocarbon source according to which: a) the hydrocarbon source is subjected to a first cracking step, namely a pyrolysis step carried out in a cracking oven, thus producing a mixture of cracking products; b) the said mixture of cracking products is subjected to a succession of treatment steps, including a compression step, which makes it possible to obtain a purified crude gas stream; c) the purified crude gas stream is then cooled to a temperature where hydrocarbons with 6 and more carbon atoms condense so that they can be removed from the purified crude gas stream; d) the resulting purified gas stream is afterwards supplied to one separating column, where a fraction containing hydrogen, methane and ethylene (fraction A) is separated at the head of the column and a heavy fraction (fraction C) is separated at the bottom of the column; e) a part of the reflux of this column is supplied to a refrigeration cycle leading to a fraction enriched with ethylene (fraction B); f) fraction A and fraction B are separately supplied to chemical use of ethylene.