Does divorce occur if the husband says: "If you do not come on a specific day, you are divorced, then divorced, then divorced," if the day passes and the wife does not return, given that the husband claimed he intended to threaten and not to divorce?

Writing is a form of kinayah (allusion/indirect expression), and divorce does not occur through kinayah unless there is an intention. The husband stated that he did not intend divorce, and therefore, it does not take place. The preferred view is that divorce does not occur unless the writing is accompanied by the intention for it to take effect.