Found error in Wiki
Silicon ingots is
And actually there must be no oxygen for reaction Si + C -> SiC.
With oxygen it would be Si + C + 4O -> SiO2 + CO2.
Actually the way to produce Graphene should have two steps:
1) Si + C -> SiC in Blast Furnace.
2) SiC -> Graphene in Laser Engraver
But i have no way to add new item unfortunately.
And seems like something wrong with second input parameter in GTTweaker-1.7.10-1.0.6.
Adds recipe with only one input (Graphite dust -> Grtaphene dust)