GST REVERSAL UNDER RULE 32

Pls suggest regarding my query.
A Dealer who runs an oil Mill purchases a cotton seed which is taxable @ 5%.
For example we may consider he purchase cotton seed for rs 1000000 and gst on it is rs. 50000.
Now he sale out 50% cotton seed as it is after adding his profit and for remaining 50% he put into crushing and two products get manufactured 1 is Oil and another is Cotton cake. Here cotton cake is exempted and oil is taxable from the manufacturing process 92% cake is manufactured and only 8% oil is manufactured. Now he has to make reversal of itc so my query is will he be able to take 50% itc fully which he have sold out as it is and for remaining 50% Rule 42 of gst reversal will apply or for full 100% Itc