GB748474A - Improvements in method and apparatus for introducing solid materials into molten metal - Google Patents

Abstract

748,474. Making and refining alloys; refining steel and other metals. AIR REDUCTION CO., Inc. Nov. 10, 1953 [Dec. 9, 1952], No. 31143/53. Classes 72 and 82(1). A finely divided solid of low density such as calcium carbide or magnesium metal is introduced into molten metal to effect a refining reaction or for alloying by forming a gasfluidised stream containing at least one-half pound of solid per cubic foot of gas and projecting the stream at a velocity exceeding 25 ft./sec. into the molten metal beneath the surface so that the solid particles penetrate the gas-molten metal interface into the molten metal. As shown, gas (which may be oxidising such as air or CO 2 , or neutral, inert or reducing such as A, N 2 or propane) from a cylinder 9 passes through regulator valves and a flowmeter to the fluidising column 8 which is maintained approximately 2/3 full of calcium carbide of minus 48 mesh from a funnel 7, and a funnel 20 draws off a stream of carbide and gas for delivery through pipe 17 to the receptacle 5 of molten iron. The velocity of the fluidising gas in the column 8 is preferably 0À1-0À3 ft./sec., and the gas leaving the top of the column via standpipe 14 is filtered at 15 and escapes to atmosphere at 16, a line 21 enabling gas to be supplied to a venturi-type ejector at the base of cone 20. Any block in the line 17 may be removed by opening valve 24 to admit a purging stream of gas. U.S.A. Specification 2,577,764 is referred to.