US3816720A — Process for the decarburization of molten metal

Claim 1

Independent Claim 25 words

calculating a theoretical equilibrium partial pressure of carbon monoxide for the oxidation reaction of each element by means of said coefficients at said given temperature;

Claim 2

Dependent Claim 21 words

A process as defined in claim 1 wherein each predetermined time interval in step (d) is between 3 to 30 seconds.

Claim 3

Dependent Claim 25 words

calculating a theoretical equilibrium partial pressure of carbon monoxide for the oxidation reaction of each element by means of said coefficients at said given temperature;

Claim 4

Dependent Claim 25 words

calculating a theoretical equilibrium partial pressure Of carbon monoxide for the oxidation reaction of each element by means of said coefficients at said given temperature;

Claim 5

Dependent Claim 25 words

calculating a theoretical equilibrium partial pressure of carbon monoxide for the oxidation reaction of each element by means of said coefficients at said given temperature;

Claim 6

Dependent Claim 19 words

calculating the absolute maximum partial pressure of carbon monoxide assuming all the oxygen injected reacted solely with the carbon;

Claim 7

Dependent Claim 19 words

calculating the absolute maximum partial pressure of carbon monoxide assuming all the oxygen injected reacted solely with the carbon;

Claim 8

Dependent Claim 19 words

calculating the absolute maximum partial pressure of carbon monoxide assuming all the oxygen injected reacted solely with the carbon;

Claim 9

Dependent Claim 28 words

A process as defined in claim 2 wherein said diluting gas is selected from one of the following gases; helium, neon, argon, krypton, nitrogen, xenon and mixtures thereof.

Claim 10

Dependent Claim 19 words

calculating the absolute maximum partial pressure of carbon monoxide assuming all the oxygen injected reacted solely with the carbon;

Claim 11

Dependent Claim 23 words

comparing the absolute maximum partial pressure of carbon monoxide from (3) with the lowest theoretical equilibrium partial pressure of carbon monoxide from (2);

Claim 12

Dependent Claim 111 words

A process as defined in claim 3 wherein the theoretical equilibrium partial pressure of carbon monoxide for each element is calculated, utilizing the computer, in accordance with the following equations: K exp Delta F*/-RT (1) K aMx/y PCOe/aM i/y O aC (2) Where: K equilibrium constant, Delta F* standard free energy of the reaction; T temperature (*K); R is the gas constant; M is any metallic element; C and O represent carbon and oxygen respectively; x and y are integers which represent the chemical formula of the metallic oxide in question. aM activity of the specific element; cC activity of dissolved carbon; and PCOe theoretical equilibrium partial pressure of carbon monoxide.

Claim 13

Dependent Claim 23 words

comparing the absolute maximum partial pressure of carbon monoxide from (3) with the lowest theoretical equilibrium partial pressure of carbon monoxide from (2);

Claim 14

Dependent Claim 23 words

comparing the absolute maximum partial pressure of carbon monoxide from (3) with the lowest theoretical equilibrium partial pressure of carbon monoxide from (2);

Claim 15

Dependent Claim 23 words

comparing the absolute maximum partial pressure of carbon monoxide from (3) with the lowest theoretical equilibrium partial pressure of carbon monoxide from (2);

Claim 16

Dependent Claim 62 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude greater than the absolute maximum partial pressure and from said determination if such theoretical partial pressure is greater than the absolute maximum partial pressure then further calculate using first gas flow rates, the amount of carbon oxidized and a new metal analysis and temperature for the composition;

Claim 17

Dependent Claim 64 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude greater than the absolute maximum partial pressure and from said determination if such theoretical equilibrium partial pressure is greater than the absolute maximum partial pressure then further calculate from said first gas flow rates, the amount of carbon oxidized and a new metal analysis and temperature for the composition;

Claim 18

Dependent Claim 63 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude greater than the absolute maximum partial pressure and if such theoretical partial pressure is of a magnitude lower than the absolute maximum partial pressure then further calculate from said first gas flow rates, the amount of carbon oxidized and a new metal analysis and temperature for the composition;

Claim 19

Dependent Claim 23 words

A process as defined in claim 4 wherein the computer is used to carry out the following additional steps prior to step (c);

Claim 20

Dependent Claim 63 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude greater than the absolute maximum partial pressure and from said determination if such theoretical partial pressure is greater than the absolute maximum partial pressure then further calculate using said first gas flow rates, the amount of carbon oxidized and a new metal analysis and temperature for the composition;

Claim 21

Dependent Claim 78 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude of less than such absolute maximum partial pressure and from said determination if such theoretical partial pressure is of a magnitude lower than the absolute maximum partial pressure then further calculate from the theoretical equilibrium partial pressure of carbon monoxide and from said first gas flow rates the amounts of carbon and metal oxidized, a new metal analysis and temperature for the composition;

Claim 22

Dependent Claim 75 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude of less than such absolute maximum partial pressure and if such theoretical partial pressure is of a magnitude lower than the absolute maximum partial pressure then further calculate from the theoretical equilibrium partial pressure of carbon monoxide and from said first gas flow rates the amounts of carbon and metal oxidized, a new metal analysis and temperature for the composition;

Claim 23

Dependent Claim 75 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude of less than such absolute maximum partial pressure and if such theoretical partial pressure is of a magnitude lower than the absolute maximum partial pressure then further calculate from the theoretical equilibrium partial pressure of carbon monoxide and from said first gas flow rates the amounts of carbon and metal oxidized, a new metal analysis and temperature for the composition;

Claim 24

Dependent Claim 81 words

A process as defined in claim 5 wherein prior to step (c) said molten mass is heated in accordance with said step (12) by resetting said adjustable gas flow control means to establish a second flow rate with the proportion of oxygen to diluting gas being at least equal to said first flow rate setting and further comprises the steps of repeating the sequence from step (1) until the temperature from steps (5) and (6) lies within said selected temperature band.

Claim 25

Dependent Claim 78 words

make a determination as to whether the lowest theoretical equilibrium partial pressure has a magnitude of less than such absolute maximum partial pressure and from said determination if such theoretical partial pressure is of a magnitude lower than the absolute maximum partial pressure then further calculate from the theoretical equilibrium partial pressure of carbon monoxide and from said first gas flow rates the amounts of carbon and metal oxidized, a new metal analysis and temperature for the composition;

Claim 26

Dependent Claim 13 words

providing an indication of the remaining carbon level from steps (5) and (6);

Claim 27

Dependent Claim 56 words

A process as defined in claim 6 wherein prior to step (c) said molten mass is heated in accordance with step (12) by adding a deoxidizer to said molten mass and further comprises the steps of repeating the sequence from step (1) until the temperature from steps (5) and (6) lies within said selected temperature band.

Claim 28

Dependent Claim 16 words

providing an indication of the remaining carbon level in said mass from steps (5) and (6);

Claim 29

Dependent Claim 21 words

providing an indication to advance the setting of said adjustable gas flow control means upon the expiration of predetermined time intervals;

Claim 30

Dependent Claim 11 words

providing an indication of said new carbon content in said mass;

Claim 31

Dependent Claim 23 words

comparing the amount of oxidation of a specific single element in said mass with a preestablished limit of oxidation for said specific element;

Claim 32

Dependent Claim 80 words

comparing the carbon level of steps (5) and (6) with a preestablished final carbon level; c. advancing the setting of said adjustable gas flow control means to the next consecutive position in said sequence in accordance with the indication provided in step (7); d. repeating the sequence from step (1) at predetermined time intervals of less than 2 minutes; and e. terminating the process when the carbon level of steps (5) and (6) at least reaches said final carbon level.

Claim 33

Dependent Claim 28 words

comparing the carbon level of step (7) with a plurality of carbon level ranges, each range corresponding to a discrete position of said adjustable gas flow control means;

Claim 34

Dependent Claim 24 words

A process as defined in claim 7 wherein said deoxidizer is selected from one of the following; silicon, aluminum, manganese, ferrosilicon, ferrochromium and ferromanganese.

Claim 35

Dependent Claim 25 words

comparing the temperature from steps (5) and (6) with a plurality of temperature ranges each range corresponding to a predetermined one of said discrete positions;

Claim 36

Dependent Claim 19 words

selecting the termperature range from said plurality of ranges in which said temperature from steps (5) and (6) resides;

Claim 37

Dependent Claim 67 words

A process as defined in claim 5 wherein prior to step (c) said molten mass is cooled in accordance with the indication provided in step (13) by inhibiting said flow of oxygen and diluting gas for a predetermined period of time and further comprises the steps of repeating the sequence from step (1) until the temperature from steps (5) and (6) lies within said selected temperature band.

Claim 38

Dependent Claim 19 words

selecting one carbon level range from said plurality of ranges in which the carbon level of step (7) resides;

Claim 39

Dependent Claim 86 words

providing an indication for resetting said adjustable gas flow control means to increase the proportion of diluting gas should the amount of oxidation of said specific element be at least equal to said preestablished limit of oxidation; c. resetting said adjustable gas flow control means in accordance with the indication provided in step (9) d. repeating the sequence from step (1) at predetermined time intervals of less than two minutes until the carbon content indicated in step (7) has at least decreased to a predetermined content.

Claim 40

Dependent Claim 23 words

selecting a temperature band, from a preestablished acceptable temperature band correlative with carbon content, at the carbon level from steps (5) and (6);

Claim 41

Dependent Claim 68 words

providing an indication for setting said adjustable flow control means to a position corresponding to the range selected in step (9); c. setting said adjustable gas flow control means in accordance with the indication provided in step (10) and d. repeating the sequence from step (1) at predetermined time intervals of less than two minutes until the carbon level indicated in step (7) reaches preestablished final carbon level.

Claim 42

Dependent Claim 56 words

A process as defined in claim 5 wherein prior to step (c) said molten mass is cooled in accordance with the indication provided in step (13) by adding a coolant and further comprises the steps of repeating the sequence from step (1) until the temperature from steps (5) and (6) lies within said selected temperature band.

Claim 43

Dependent Claim 66 words

providing an indication for resetting said adjustable gas flow control means in accordance with the temperature range selected in step (9); c. setting said adjustable control means in accordance with the indication provided in step (10); d. repeating the sequence from step (1) at predetermined time intervals of less than 2 minutes until the carbon level from steps (5) and (6) reaches a predetermined final level.

Claim 44

Dependent Claim 15 words

A process as defined in claim 10 wherein said coolant is a solid scrap material.

Claim 45

Dependent Claim 16 words

comparing the temperature of steps (5) and (6) with the selected temperature band of step (10);

Claim 46

Dependent Claim 18 words

providing an indication to heat said molten mass if such temperature lies below said selected temperature band; and

Claim 47

Dependent Claim 77 words

A process as defined in claim 11 further comprising the step of calculating the amount of scrap material to be added in accordance with the following equation: S (T - (Tmax + Tmin)/2) C Where: S scrap addition; T temperature in *K oF the mass at the end of a predetermined time interval; Tmax upper temperature limit of said selected temperature range; Tmin lower temperature limit of said selected temperature range; and C is a proportionality coefficient.

Claim 48

Dependent Claim 23 words

A process as defined in claim 10 wherein said coolant is a fluid selected from one of the following; steam and carbon dioxide.

Claim 49

Dependent Claim 17 words

providing an indication to cool said molten mass if such temperature lies above said selected temperature band.

Claim 50

Dependent Claim 33 words

A process as defined in claim 5 wherein said specific element is iron and wherein the preestablished limit of oxidation for said specific element is a fixed limit for each predetermined time interval.

Claim 51

Dependent Claim 14 words

A process as defined in claim 5 wherein said composition in addition comprises chromium.

Claim 52

Dependent Claim 16 words

A process as defined in claim 15 wherein said composition in addition comprises silicon and manganese.

Claim 53

Dependent Claim 14 words

A process as defined in claim 16 wherein said composition in addition comprises nickel.

Claim 54

Dependent Claim 17 words

A process as defined in claim 15 wherein said composition in addition comprises nickel, molybdenum and niobium.

Claim 55

Dependent Claim 103 words

A process as defined in claim 16 wherein said specific element is chromium and wherein the limit of oxidation for each time interval is established in accordance with the following equation: Volume % Oxygen FO /FO + FIG Square Root 13, 000/(Percent Cr/Percent C antilog(13,800/I-8.46)) 1 Where: FO flow of oxygen; FIG flow of inert gas; Percent Chromium limit weight percentage of chromium that should remain in the bath at the end of each time interval; Percent C the percent carbon by wieght at the end of each time interval; and at T temperature in *K at the end of each time interval.

Claim 56

Dependent Claim 39 words

A process as defined in claim 17 wherein said specific element is selected from the class consisting of chromium, molybdenum and niobium and wherein the limit of oxidation is predetermined for each element and for each predetermined time interval.

Claim 57

Dependent Claim 92 words

A process as defined by claim 5 wherein said adjustable control means includes a predetermined number of discrete settings arranged in a predetermined sequence with each setting defining a fixed ratio of oxygen to diluting gas, and wherein the output of the computer is connected to said adjustable control means for automatically advancing said means in accordance with step (c) from said initially set first position to the next consecutive position once the oxidation of the specific element of interest is at least equal to the limit of oxidation for said element.

Claim 58

Dependent Claim 102 words

A process for making steel by refining a predetermined mass of molten metal having a composition comprising carbon and iron, said mass being contained within a refractory lined vessel having means for injecting oxygen and a diluting gas therein, and adjustable gas flow control means having a predetermined number of discrete positions with each position defining a fixed ratio of gas flow between the respective gases; said process comprising: a. setting said adjustable control means to a first position for establishing a first gas flow rate for said respective gases; b. utilizing a computer to carry out the following sequence of steps:

Claim 59

Dependent Claim 21 words

A process as defined in claim 22 wherein each predetermined time interval in step (d) is between 3 to 30 seconds.

Claim 60

Dependent Claim 28 words

A process as defined in claim 23 wherein said diluting gas is selected from one of the following gases; helium, neon, argon, krypton, nitrogen, xenon and mixtures thereof.

Claim 61

Dependent Claim 111 words

A process as defined in claim 24 wherein the theoretical equilibrium partial pressure of carbon monoxide for each element is calculated, utilizing the computer, in accordance with the following equations: K exp Delta F*/-RT (1); K aMx/y PCOe/aM i/y O aC (2) Where: K equilibrium constant, Delta F* standard free energy of the reaction; T temperature (*K); R is the gas constant; M is any metallic element; C and O represent carbon and oxygen respectively; x and y are integers which represent the chemical formula of the metallic oxide in question. aM activity of the specific element; aC activity of dissolved carbon; and PCOe theoretical equilibrium partial pressure of carbon monoxide.

Claim 62

Dependent Claim 14 words

A process as defined in claim 25 wherein said composition in addition comprises chromium.

Claim 63

Dependent Claim 16 words

A process as defined in claim 26 wherein said composition in addition comprises silicon and manganese.

Claim 64

Dependent Claim 14 words

A process as defined in claim 27 wherein said composition in addition comprises nickel.

Claim 65

Dependent Claim 17 words

A process as defined in claim 26 wherein said composition in addition comprises nickel, molybdenum and niobium.

Claim 66

Dependent Claim 109 words

A process for makinG steel by refining a predetermined mass of molten metal having a composition comprising carbon and iron, said mass being contained within a refractory lined veseel having means for injecting oxygen and a diluting gas therein, and adjustable gas flow control means having a predetermined number of discrete positions arranged in a predetermined sequence with each position defining a fixed ratio of gas flow between the respective gases, said process comprising: a. setting said adjustable gas flow control means to a first position for establishing a first gas flow rate for said respective gases; b. utilizing a computer to carry out the following sequence of steps:

Claim 67

Dependent Claim 21 words

A process as defined in claim 30 wherein each predetermined time interval in step (d) is between 3 and 30 seconds.

Claim 68

Dependent Claim 26 words

A process as defined in claim 31 wherein said diluting gss is selected from the following gases; helium, neon, argon, krypton, nitrogen, xenon and mixtures thereof.

Claim 69

Dependent Claim 111 words

A process as defined in claim 32 wherein the theoretical equilibrium partial pressure of carbon monoxide for each element is calculated, utilizing the computer, in accordance with the following equations: K exp Delta F*/-RT (1); K aMx/y PCOe/aM i/y O aC (2) Where: K equilibrium constant, Delta F* standard free energy of the reaction; T temperature (*K); R is the gas constant; M is any metallic element; C and O represent carbon and oxygen respectively; x and y are integers which represent the chemical formula of the metallic oxide in question. aM activity of the specific element; aC activity of dissolved carbon; and PCOe theoretical equilibrium partial pressure of carbon monoxide.

Claim 70

Dependent Claim 14 words

A process as defined in claim 33 wherein said composition in addition comprises chromium.

Claim 71

Dependent Claim 16 words

A process as defined in claim 34 wherein said composition in addition comprises silicon and manganese.

Claim 72

Dependent Claim 14 words

A process as defined in claim 35 wherein said composition in addition comprises nickel.

Claim 73

Dependent Claim 17 words

A process as defined in claim 34 wherein said composition in addition comprises nickel, molybdenum and niobium.

Claim 74

Dependent Claim 102 words

A process for making steel by refining a predetermined mass of molten metal having a composition comprising carbon and iron, said mass being contained within a refractory lined vessel having means for injecting oxygen and a diluting gas therein, and adjustable gas flow control means having a predetermined number of discrete positions with each position defining a fixed ratio of gas flow between the respective gases; said process comprising: a. setting said adjustable control means to a first position for establishing a first gas flow rate for said respective gases; b. utilizing a computer to carry out the following sequence of steps:

Claim 75

Dependent Claim 21 words

A process as defined in claim 38 wherein each predetermined time interval in step (d) is between 3 to 30 seconds.

Claim 76

Dependent Claim 26 words

A process as defined in claim 39 wherein said diluting gas is selected from the following gases helium, neon, argon, krypton, nitrogen, xenon and mixtures thereof.

Claim 77

Dependent Claim 111 words

A process as defined in claim 40 wherein the theoretical equilibrium partial pressure of carbon monoxide for each element is calculated, utilizing the computer, in accordance with the following equations: K exp Delta F*/-RT (1); K aMx/y PCOe/aM i/y O aC (2) Where: K equilibrium constant, Delta F* standard free energy of the reaction; T temperature (*K); R is the gas constant; M is any metallic element; C and O represent carbon and oxygen respectively; x and y are integers which represent the chemical formula of the metallic oxide in question. aM activity of the specific element; aC activity of dissolved carbon; and PCOe theoretical equilibrium partial pressure of carbon monoxide.

Claim 78

Dependent Claim 14 words

A process as defined in claim 41 wherein said composition in addition comprises chromium.

Claim 79

Dependent Claim 16 words

A process as defined in claim 42 wherein said composition in addition comprises silicon and manganese.

Claim 80

Dependent Claim 14 words

A process as defined in claim 43 wherein said composition in addition comprises nickel.

Claim 81

Dependent Claim 17 words

A process as defined in claim 42 wherein said composition in addition comprises nickel, molybdenum and niobium.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1977-06-10	1977-12-10	1978-06-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1981-06-10	1981-12-10	1982-06-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1985-06-10	1985-12-10	1986-06-11	$7700.00	Window Closed / Lapsed

Process for the decarburization of molten metal

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