Does divorce occur upon the husband's saying to his wife: "When we return home, go to your family's house; I will divorce you"?

Divorce does not occur by promising it. The phrase mentioned is a promise of divorce, not an actualization of it. A promise of divorce does not take effect merely by uttering it, nor is one obligated to fulfill it. Rather, it is not even recommended to do so, as mentioned by Sheikh al-Islam Ibn Taymiyyah.