Apparatus and method for submerged injection of a feed composition into a molten metal bath

A method for cooling a lance for submerged injection of a feed composition into a molten metal bath, comprising the steps of:

• a) directing the feed composition through an injection tube of the lance into the molten metal bath;
• and
• b) directing a coolant from a coolant source and through an annulus defined by the injection tube and a perforate support liner, said perforate support liner being substantially coaxial to the injection tube and located between the injection tube and a perforate refractory tube and supporting said refractory tube, said perforate refractory tube defining the perforations and shielding the injection tube from the molten metal bath during partial submersion of the lance in the molten metal bath, whereby coolant is directed through perforations of the perforate support liner and the perforate refractory tube, and into the molten metal bath, thereby cooling the lance during submerged injection of the feed composition through the injection tube into the molten metal bath.

In a lance for submerged injection of a feed composition into a molten metal bath, said lance including an injection tube, for conducting the feed composition through the lance and into the molten metal bath, and a perforate refractory tube which extends substantially coaxially about the injection tube for shielding the injection tube from the molten metal bath during partial submersion of the lance into the molten metal bath:

• the improvement comprising a perforate support liner between the injection tube and the perforate refractory tube and supporting the refractory tube, the perforate support liner and the injection tube defining an annulus for conducting a coolant from a coolant source and through the annulus to perforations defined by the perforate support liner and the perforate refractory tube, whereby coolant can be directed through said perforations and into the molten metal bath, thereby cooling the lance during submerged injection of the feed composition through the injection tube into the molten metal bath.

A method for protecting the structural and chemical integrity of a lance for submerged injection of a hazardous material into a molten metal bath, comprising the steps of:

• a) directing the hazardous material through an injection tube of the lance into the molten metal bath;
• and
• b) directing a coolant from a coolant source and through an annulus defined by the injection tube and a perforate support liner, said perforate support liner being substantially coaxial to the injection tube and located between the injection tube and a perforate refractory tube and supporting said perforate refractory tube, said perforate refractory tube shielding the injection tube from the molten metal bath during partial submersion of the lance into the molten metal bath, whereby coolant is directed through perforations which are defined by the perforate support liner and the perforate refractory tube, and into the molten metal bath, thereby protecting the structural and chemical integrity of the lance by forming an accretion on the surface of the partially submerged lance during submerged injection of the hazardous material through the injection tube into the molten metal bath.