@wilcolandzaat uses Sanke kegs. Hopefully he will chime in. The biggest challenge with a commercial keg like that is disassembling and cleaning. Most of us use soda kegs because the lids are easily removed to clean and inspect plus they are 5 gallon, the amount most of us brew (or a multiple of 5). There is also a ton of parts and equipment available for soda kegs that are used for homebrew.
Might want to consider seeing if you can turn that keg in for the deposit and put the money toward soda kegs. Technically the keg that was given to you belongs to the brewery. That said many of us have cut the tops off them to be used as a kettle so let your conscience be your guide.