Personally, I wouldn't try and weld the tang back on.
Even if you're a skilful welder (or get one to do the job for you), there are various factors at work against your chances of success.
1.You'll be joining two pieces of high carbon steel with low carbon steel (welding rod). Although the join, once ground out, may look like it's back to being one piece of metal, it's still two pieces of Material Type A held together by a dab of Material Type B. The join will always be a potential weak spot.
2. The welding process will anneal (soften) the steel at the base of the blade. I welded my 30" Kobra when the tang busted off. Under hard use, the weld held up, but the blade tore apart right through the cho, like toffee, because the weld had softened up the steel
3. Welding introduces enormous stresses into the steel of the blade, doing nasty & unpredictable things to its crystalline structure. As well as annealing the steel, it can sometimes have the reverse effect and spot-harden it, making the blade brittle.
(This is why the cheapskate Spanish, Chinese and Filipino swords with welded-on rat-tail tangs are accidents waiting to happen. Nine time sout of ten, when they fail, they fail at the junction of tang and blade. Doesn't matter if the welding was done before the heat treatment - in fact, that can be worse, as the high-carbon steel reacts differently to the heat than the low-carbon weld, creating a weak spot)
If you want to weld the khuk up and hang it on the wall, fine. Personally, I wouldn't ever use it again. Imagine what might happen if the blade shore off during heavy chopping and went flying through the air - now that (as Crocodile Dundee would say) is what I call a throwing knife...