Does divorce take place with the words, "Divorce upon me if you do not do it, then you are not under my responsibility," with the intention of threat, and how does the return (reconciliation) occur for the traveler?

The phrasing included an oath with an innuendo of divorce, "You are not under my responsibility." Divorce does not occur with this phrase unless there is an intention. Since you only intended it as a threat, divorce does not occur even if you broke your oath, and your wife remains under your marital bond, and there is no need to take her back. Note that the wife's presence is not required for a رجعة (revocation of divorce).