Abstract Method for injecting a gaseous reaction agent into a bath of molten metal by the use of a submerged nozzle to achieve the generation of a mass of very fine bubbles throughout a substantial portion of the bath. The bubbles mix and stir the bath to effect chemical homogeneity with a minimum amount of splashing and slopping of the molten metal and persist for a time sufficient to promote substantially complete reaction of the gas phase with the environmental fluid. By selecting a bubble diameter from a consideration of the desired gas flow rate and appropriate Reynolds number, the gas issuing into the molten bath will disperse into small bubbles of essentially constant diameter to maximize the gas-liquid interfacial area. Additionally, by controlling the pressure of the gas forced through the nozzle, the penetration of the fine bubbles into the bath can be controlled to achieve maximum stirring and optimum bubble retention time within the bath without damaging the refractory lining of the vessel containing the bath.
The method of claim 1 wherein the injection pressure of gas in the nozzle is determined and controlled in accordance with the equations: Lv 0.527 + 0.87 Podo Cos theta Lh 4.16 + 1.526 Podo Sin theta where Lv is the vertical penetration of the bubbles, Lh is the horizontal penetration of the bubbles, do is the diameter of the nozzle, and theta is the angle of inclination of the nozzle with respect to vertical.
Claim 2
Dependent Claim
12 words
The method of claim 1 wherein there is a plurality of nozzles.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein said nozzle is projected through a side wall of a vessel containing said molten metal bath.
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein said nozzle is disposed on the bottom of a lance which projects into and through the surface of said molten metal bath.
Claim 5
Dependent Claim
56 words
The method of claim 1 wherein horizontal penetration, of the gas into the bath is equal to at least one-third of the total distance from said orifice to the opposite refractory lining of said vessel, and vertical penetration of the gas into the bath is equal to at least one-third of the depth of said bath.
Claim 6
Dependent Claim
152 words
The method of claim 1 wherein, for a preselected desired gas mass flow rate, preselected desired horizontal and vertical penetrations of said gas through said bath, a preselected desired angle of inclination of said nozzle with respect to vertical, and a preselected Reynolds number not less than 10,000, said orifice diameter is selected and adapted in accordance with the equation: NRe 4W/( pi do Mu ) wherein NRe is the Reynolds number, W is the gas mass flow rate and Mu is the gas viscosity, and said injection pressure is selected and adapted in accordance with the equations: Lv 0.527 + 0.87 Podo cos theta Ln 4.16 + 1.526 Podo sin theta wherein Lv is vertical penetration of gas bubbles, Ln is horizontal penetration of gas bubbles, do is the cumulative orifice diameter, Po is the injection pressure, and theta is the angle of inclination of the nozzle with respect to vertical.