No, the metals are just too dissimilar. The aluminium will be a molten puddle on the floor before the cast iron is starting to soften.
It might be possible with some exotic welding process like friction welding, but it's not a realistic proposition. Drilling holes and bolting the flange on would be more sensible.
steel/iron and aluminium do not weld together without a very sophisticated process. I'm sure they can be brazed together? But not sure if That would work well enough for this application.
as above weld a flange to the Ali then bolt to the cast iron
if its nit magnetic its Ali, which would be more common than cast iron and you can weld to it with a 4043 rod depending on the grade of Ali the flange to be welded on is made from. Cant see it being anything exotic though