As you already know, reacting in like fashion to your son's anger will only exacerbate the situation. A frequent mistake we make as parents is failing to act with equanimity when our children are angry. To be aangry in return only adds fuel to the fire.
Now, if these eruptions of anger are of recent origin, and not a chronic pattern, it may well be that recent developments with his father are at the root of them and require some clarification. Your son may be troubled at the contact and holding you responsible for sending him. Try to figure this out a bit, and see if there's anything there. You can mention to your son that at times lately he hasn't seemed to want to go with his dad, and are there reasons he can discuss with you.