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.