You do not need magick to become emotionally detached but this is not a good thing. Yes, you may want to subdue some emotion at this precise moment but when you start to shut your heart away it can become a constant issue that can be difficult to reverse. Emotions can cause trouble at times yet they can be controlled and impulses resisted. Closing ones heart off or numbing it is something one should never do if it can be helped. If it's for a good reason then I am sure you have the strength to achieve this without magick. Also, emotions are a delicate yet powerful thing that in my mind even magick cannot subdue. It might help you to focus on your goal but you'll still need to achieve it with your inner strength.