What is the ruling on returning to one's wife after an enraged triple divorce, and does this divorce take effect?

If it was merely an internal monologue without utterance, then no divorce occurs. However, if you verbally pronounced the divorce of your wife willingly, it takes effect even if no one heard it. The fatwa adopted by us is that divorce pronounced three times counts as three, so your wife would be divorced three times and irrevocably separated from you (baynunah kubra). You cannot remarry her unless she marries another man who consummates the marriage with her, and then he divorces her or dies.

Some scholars, like Sheikh Ibn Taymiyyah, hold the view that pronouncing divorce three times counts as one divorce, and that the divorce of an angry person is not effective. It is advisable to present the matter verbally to trustworthy scholars.