What is the ruling on divorcing one's wife three times on separate occasions, knowing that the husband was very angry each time?

Anger does not prevent the occurrence of divorce unless it is so severe that it overwhelms the person's mind, making them unaware of what they are saying. If you uttered the divorce while being aware of what you were saying, then the divorce has occurred. The majority of scholars hold that a conditional divorce takes effect when the condition is met, and that uttering the triple divorce counts as three divorces. This is the fatwa we follow, contrary to Ibn Taymiyyah. Your statement to your wife, "You are divorced by the million," is considered an explicit divorce, by which a triple divorce occurs according to the majority of scholars. Therefore, if you were aware of what you were saying, your wife has become irrevocably divorced from you (baynunah kubra), and she is not lawful for you unless she marries another man willingly, and then he divorces her after consummating the marriage and her waiting period ends.