The invention concerns an apparatus (1) for injecting gas into molten metal through a molten metal-contacting surface (11) comprising i) a porous refractory body (2) substantially surrounded by a substantially non-porous body (9) except at the molten metal-contacting surface (11); and ii) gas conducting means (3,5) for conveying the gas from a gas source to the porous body (2). The apparatus is characterized in that the non-porous body (11) is made of refractory material and in that the porous and non-porous bodies (2,11) have been co-pressed. This apparatus can be used to inject efficiently and reliably small bubbles into a molten metal bath. IMAGE
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