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US3955966A Expired / Lapsed US ⏱️ 0.0 years remaining

Method for dispensing a fluidizable solid from a pressure vessel

Assignee: Thyssen AG
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Filing: 1974-07-30
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Granted: 1976-05-11
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Expires: 1994-07-30
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Abstract

Abstract An improvement in the method of desulfurizing molten pig iron by forming a fluidized stream of a solid desulfurizing agent consisting of finely divided calcium carbide which is contained in a pressure vessel which comprises a discharge connected to an immersion lance by a conveying pipe, by injecting a fluidized gas at a pressure upwardly into the desulfurization agent, withdrawing the resultant fluidized desulfurizing agent from the pressure vessel, introducing a separate stream of gas into the conveying pipe and conveying said fluidized desulfurizing agent together with the fluidizing and feeding gases into the pig iron through said immersion lance, determining the amount of the solid desulfurizing agent, and the through-flow quantity of gas flow, being the sum of amount of fluidizing gas and the amount of feeding gas, and maintaining a predetermined gas/solid ratio which improvement comprises using as the desulfurizing agent finely divided calcium carbide mixed with a solid material which decomposes or evaporates at the temperature of the molten pig iron thereby evolving a gas and withdrawing the fluidized desulfurization agent from said pressure vessel and feeding it into the molten pig iron at a rate of between 70 and 250 kilograms per minute and maintaining the gas/solid ratio at a value in the range of 2 to 12 normal liters per kilogram.

Inventors

  • 👤 Walter Meichsner

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 23:34
CPC Classifications
C; C21; C21C; C21C1/00; C21C1/02

Claims Analysis

Total Claims: 23
Claim 1
Independent Claim 222 words
In the method of desulfurizing molten pig iron by forming a fluidized stream of a solid desulfurizing agent comprising a finely divided calcium carbide, which is maintained in a pressure vessel, which vessel comprises a discharge connected with an immersion lance by a conveying pipe, by injecting a fluidizing gas upwardly into the desulfurizing agent, withdrawing fluidized desulfurizing agent from said pressure vessel, introducing a separate stream of a feeding gas into the conveying pipe and conveying said fluidized desulfurizing agent together with the fluidizing and feeding gases into the molten pig iron through said immersion lance, determining the amount of the solid desulfurizing agent, and the through flow quantity of gas flow, said through flow quantity of gas flow being the sum of the amount of fluidizing gas in the amount of feeding gas, and maintaining a predetermined constant gas/solid ratio, the improvement which comprises utilizing as the desulfurizing agent a finely divided calcium carbide mixed with a solid material which decomposes or evaporates at the temperature of said molten pig iron to evolve a gas and withdrawing the fluidized desulfurizing agent from said pressure vessel and feeding it into the molten pig iron at a rate of between 70 and 250 kilograms per minute and maintaining the gas/solid ratio at a value of 2 to 12 normal liters per kilogram.
Claim 2
Dependent Claim 222 words
In the method of desulfurizing molten pig iron by forming a fluidized stream of a solid desulfurizing agent comprising a finely divided calcium carbide, which is maintained in a pressure vessel, which vessel comprises a discharge connected with an immersion lance by a conveying pipe, by injecting a fluidizing gas upwardly into the desulfurizing agent, withdrawing fluidized desulfurizing agent from said pressure vessel, introducing a separate stream of a feeding gas into the conveying pipe and conveying said fluidized desulfurizing agent together with the fluidizing and feeding gases into the molten pig iron through said immersion lance, determining the amount of the solid desulfurizing agent, and the through flow quantity of gas flow, said through flow quantity of gas flow being the sum of the amount of fluidizing gas in the amount of feeding gas, and maintaining a predetermined constant gas/solid ratio, the improvement which comprises utilizing as the desulfurizing agent a finely divided calcium carbide mixed with a solid material which decomposes or evaporates at the temperature of said molten pig iron to evolve a gas and withdrawing the fluidized desulfurizing agent from said pressure vessel and feeding it into the molten pig iron at a rate of between 70 and 250 kilograms per minute and maintaining the gas/solid ratio at a value of 2 to 12 normal liters per kilogram.
Claim 3
Dependent Claim 15 words
A method according to claim 1 wherein the gas evolving material is natural calcium carbonate.
Claim 4
Dependent Claim 13 words
A method according to claim 2 wherein the gas evolving material is limestone.
Claim 5
Dependent Claim 18 words
A method according to claim 1 wherein the gas evolving material is natural calcium carbonate mixed with carbon.
Claim 6
Dependent Claim 15 words
A method according to claim 1 wherein the gas evolving material is precipitated calcium carbonate.
Claim 7
Dependent Claim 17 words
A method according to claim 1 wherein the gas evolving material is precipitated calcium carbonate containing carbon.
Claim 8
Dependent Claim 15 words
A method according to claim 1 wherein the gas evolving material is a calcium-magnesium carbonate.
Claim 9
Dependent Claim 14 words
A method according to claim 1 wherein the gas evolving material is raw dolomite.
Claim 10
Dependent Claim 14 words
A method according to claim 1 wherein the gas evolving material is magnesium carbonate.
Claim 11
Dependent Claim 14 words
A method according to claim 9 wherein the gas evolving material is raw magnesite.
Claim 12
Dependent Claim 13 words
A method according to claim 1 wherein the gas evolving material is polyethylene.
Claim 13
Dependent Claim 14 words
A method according to claim 1 wherein the gas evolving material is a polyamide.
Claim 14
Dependent Claim 13 words
A method according to claim 1 wherein the gas evolving material is dicyandimide.
Claim 15
Dependent Claim 14 words
A method according to claim 1 wherein the gas evolving material is calcium hydroxide.
Claim 16
Dependent Claim 14 words
A method according to claim 1 wherein the gas evolving material is a carbohydrate.
Claim 17
Dependent Claim 20 words
A method according to claim 1 wherein the gas evolving material is an alkaline earth borate containing water of recrystallization.
Claim 18
Dependent Claim 21 words
A method according to claim 1 wherein the gas evolving material comprises a mixture of two or more separate gas-evolving materials.
Claim 19
Dependent Claim 18 words
A method according to claim 1 wherein the desulfurizing agent contains as an additional component a strong deoxidizer.
Claim 20
Dependent Claim 12 words
A method according to claim 18 wherein the strong deoxidizer is aluminum.
Claim 21
Dependent Claim 12 words
A method according to claim 18 wherein the strong deoxidizer is calcium.
Claim 22
Dependent Claim 55 words
A method according to claim 1 wherein the fluidized desulfurization agent is withdrawn from the pressure vessel and introduced into the molten pig iron at a rate of between 80 and 140 kilograms per minute and the gas/solid ratio is maintained at a value in the range of 2 to 8 normal liters per kilogram.
Claim 23
Dependent Claim 55 words
A method according to claim 1 wherein the fluidized desulfurizing agent is withdrawn from the pressure vessel and introduced into the molten pig iron at a rate of between 100 and 120 kilograms per minute and the gas/solid ratio is maintained at a value in the range of 4 to 6 normal liters per kilgram.

References Cited (Backward Citations)

US1922037A Cited
US2779675A Cited
US2803533A Cited
US3368885A Cited
US3575695A Cited
US3598573A Cited
US3551139A Cited
US3702151A Cited
US3716352A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1979-05-11 1979-11-10 1980-05-11 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1983-05-11 1983-11-10 1984-05-11 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1987-05-11 1987-11-10 1988-05-11 $7700.00 Window Closed / Lapsed

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