A rotary lance drive for rotating a lance for injecting gas and powdered reagents into molten metal, the rotary lance drive comprising: a main support having a support housing and a pair of rotary bearings arranged respectively adjacent an upper end and a lower end of the support housing; a hollow shaft extending vertically through the support housing and supported by the pair of rotary bearings for rotation about a vertical axis; a drive motor drivably connected to the hollow shaft, the drive motor being operable to rotate the hollow shaft about the vertical axis; a lance mount rigidly connected to the hollow shaft for rotation with the hollow shaft, the lance mount being configured to permit a lance to be removably held by the lance mount for rotation with the lance mount; a transport pipe extending vertically through the hollow shaft into the lance mount, a bottom end of the transport pipe being connectable to a lance held by the lance mount; and a swivel coupling receiving a top end of the transport pipe, the swivel coupling permitting connection of a flexible reagent supply hose to the transport pipe and allowing relative rotation between the transport pipe and the supply hose, the swivel coupling including an inner part partially extending into an outer part; characterised in that: the pair of rotary bearings are external to the support housing; and, the swivel coupling is arranged such that reagent from the supply hose enters the swivel coupling through the inner part and exits the swivel coupling through the outer part. a main support having a support housing and a pair of rotary bearings arranged respectively adjacent an upper end and a lower end of the support housing; a hollow shaft extending vertically through the support housing and supported by the pair of rotary bearings for rotation about a vertical axis; a drive motor drivably connected to the hollow shaft, the drive motor being operable to rotate the hollow shaft about the vertical axis; a lance mount rigidly connected to the hollow shaft for rotation with the hollow shaft, the lance mount being configured to permit a lance to be removably held by the lance mount for rotation with the lance mount; a transport pipe extending vertically through the hollow shaft into the lance mount, a bottom end of the transport pipe being connectable to a lance held by the lance mount; and a swivel coupling receiving a top end of the transport pipe, the swivel coupling permitting connection of a flexible reagent supply hose to the transport pipe and allowing relative rotation between the transport pipe and the supply hose, the swivel coupling including an inner part partially extending into an outer part; characterised in that: the pair of rotary bearings are external to the support housing; and, the swivel coupling is arranged such that reagent from the supply hose enters the swivel coupling through the inner part and exits the swivel coupling through the outer part. the pair of rotary bearings are external to the support housing; and, the swivel coupling is arranged such that reagent from the supply hose enters the swivel coupling through the inner part and exits the swivel coupling through the outer part.