Abstract: Disclosed is an apparatus for chlorination of molten magnesium chloride salts, comprising a shell lined with a refractory material and having the interior thereof formed by walls, a bottom and a cover. The lower portion of the shell walls is provided with chlorine inlet means whereas the upper one has a melt feed inlet means and a chlorinated melt outlet means. The interior of the shell is so tapered downward that its clear opening at the level of the chlorine inlet means is not over 0.3 times that at the level of the melt feed inlet means and the chlorinated melt outlet means.