Dear Bahadur (Famous name from the mogul emperors!)
Exellent question! Very practical (and therefore rare on this platform) - implements the knowledge, that only a few coal types in this world, particularly the younger ones, are coke-able (maybe about 5%).
In former GDR they used even lignite to make coke. - Instead of non-coke-able coke I would try to blend with lignite. - Crush and mix it under. That is more a craftsmanship issue by trial and error. Depends of course on the cokemaking parameters of your current coal.
It will depend on caking index of the coking coal. For a good coke the mixture of coking coal and noncoking coal should give caking index of 17 or 18. For stamp charged coking higher amount may be mixed depending on stamping pressure.
It is complicated task. It depends on which coal do you use as a blend components, and required quality of coke. In terms of NSC indices (CRI and CSR): in general they are additive. To be sure you have to perform the laboratory coking tests. If you want produce superior coke (CSR > 70) you probably can not use non coking coal. If you produce coke with lower quality parameters (CSR>50) you can probably use max. 15-25% non caking coal. But the exact amount depends on individual properties of used coals (coalification, ash content and composition etc.). The higher the coalification degree of used coal, the higher amount of coal you can use, because degree of coalification influences reactivity and consequently strength of coke matrix. Essential is to remain optimal blend properties (FSI, Fluidity, dilatation, coking pressure, Volatile matter etc.) Inert additive should be finely ground also (below 0.5mm). It is helpful to carried out the laboratory tests of influence the addition of non caking coal on above mentioned blend parameters