CN100404711C - Method for preventing liquid magnesium alloy from oxidation combustion and hermetic magnesium alloy smelting furnace - Google Patents
Method for preventing liquid magnesium alloy from oxidation combustion and hermetic magnesium alloy smelting furnace Download PDFInfo
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- CN100404711C CN100404711C CNB2006100894989A CN200610089498A CN100404711C CN 100404711 C CN100404711 C CN 100404711C CN B2006100894989 A CNB2006100894989 A CN B2006100894989A CN 200610089498 A CN200610089498 A CN 200610089498A CN 100404711 C CN100404711 C CN 100404711C
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Abstract
The present invention relates to a method for preventing liquid magnesium alloy from oxidation combustion and a hermetic magnesium alloy smelting furnace, which belongs to the technical field of magnesium alloy metallurgy. In order to solve the problems that SF6 having high greenhouse effect and toxic SO2 used in the current international magnesium industrial community bring about environmental hazards and the consumption of protective gases is large, which is wasteful and adds hazards to the environment, equipment and human bodies, etc., the present invention provides a method for preventing liquid magnesium alloy from oxidation combustion via a solid metal fluoride and a hermetic magnesium alloy smelting furnace that is matched with the method. By filling the solid metal fluoride with high steam pressure into the smelting furnace at the melting temperature and charging a supporting gas or a gaseous mixture of the supporting gas and air into a melting kettle through a gas charging inlet, the present invention reaches the goal of preventing the magnesium alloy from evaporation and oxidation combustion. The present invention has the characteristics that the sealing requirement for the melting kettle is low, the present invention is saving and economic, the present invention protects the environment and can effectively prevent magnesium alloy from oxidation combustion, and the interface of operation is friendly; the present invention has high popularization and application value.
Description
Technical field
The present invention relates to a kind of method and magnesium alloy sealing smelting furnace that prevents the liquid magnesium alloy oxidizing fire, belong to the magnesium alloy metallurgical technology field.
Background technology
Remarkable advantage such as magnesium and magnesium alloy have that proportion is low, specific tenacity and specific rigidity height and the prices of raw and semifnished materials are lower, recent two decades comes Mg Alloy Research and uses the attention that is subjected to material educational circles and industry member day by day, and China classifies magnesium alloy as one of project of new millennium focus development application and industrialization.Because the chemically reactive of magnesium is very strong, in air, the rapid oxidation of liquid magnesium and alloy thereof, burning.The loose oxide film of its generation does not shield, and particularly under the high-temperature condition, the oxidizing reaction liberated heat then is easy to burning if can not in time distribute.Magnesium alloy is under smelting temperature in addition, and the vapour pressure height is easy to evaporation.Therefore when the melting magnesium alloy, must prevent magnesium alloy evaporation, burning.
The gas shield smelting technique is current main gordian technique of producing high-quality magnesium alloy.Current, magnesium industry circle carries out in open stove when melting magnesium and magnesium alloy usually, adopts successively to feed to contain SF
6Or SO
2Mixed gas do shielding gas, so use not only waste, and increase harm to environment, equipment and human body.SF
6Having very high Greenhouse effect (is CO
224000 times, in atmosphere, can have 3200), will cause climate change and global warm problem; SO
2Poisonous, thus the magnesium industry user must seek technically, on the environment and acceptable economically surrogate.Research explores and a kind ofly more to clean, saves, efficiently, the alternative protection material and the tooling of healthy, environmental protection, have the practice significance and the learning value of reality.
Summary of the invention
In order to solve the SF that current international magnesium industry circle uses the high-temperature chamber effect
6With deleterious SO
2Big, the waste of the environmental hazard that brings, shielding gas usage quantity, and increase problems such as harm to environment, equipment and human body, the present invention proposes a kind of method that prevents the liquid magnesium alloy oxidizing fire, comprise the steps:
Initiating process: the furnace charge that will dry adds the smelting pot bottom of magnesium alloy sealing smelting furnace, and the solid metal fluorochemical that will dry puts into the open containers on smelting pot lower inner wall and/or the thermoscreen lower surface, described solid metal fluorochemical be under the magnesium alloy smelting temperature vapour pressure greater than 10
-4The metal fluoride of handkerchief, described solid metal fluorochemical preferred fluorinated magnesium or aluminum fluoride; Utilize vacuum system to get rid of the interior air of smelting pot then, when gaseous tension in the crucible underspeeds less than 0.2Pa/ minute, close vacuum pump; Open inflation inlet, utilize gas input device in smelting pot, to charge into gas by inflation inlet, described gas be under melting condition not with the carrier gas of magnesium liquid reaction, or the mixed gas formed of carrier gas and air, wherein said carrier gas is N
2, one or more the miscellany among Ar, He, Ne or the Xe; When the smelting pot internal pressure is 7 * 10
4Pa～1.01 * 10
5During Pa, close inflation inlet, open the process furnace power supply, beginning melting magnesium alloy;
Fusion process: utilize tensimeter to detect the interior pressure of smelting pot in real time, the control furnace pressure; Utilize the oxygen concentration analyser to monitor the content of oxygen in the stove in real time, guarantee that oxygen partial pressure is 1 * 10 in the stove
2～8 * 10
3Pa.
In initiating process, the solid metal fluorochemical of also another part being dried is put into the smelting pot bottom.
The amount of putting into of the metal fluoride of smelting pot is to be determined jointly by smelting pot volume and magnesium alloy quality to be melted.
The present invention also provides a kind of and has sealed smelting furnace at the above-mentioned magnesium alloy that uses in the method for liquid magnesium alloy oxidizing fire that prevents, comprise smelting pot, be used for the process furnace of heating melting crucibles, charge into the gas input device of gas by the inflation inlet on the smelting pot to smelting pot, and oxygen concentration analyser in tensimeter on the bell and the stove, it is characterized in that: described smelting pot is divided into crucible bottom and crucible top by thermoscreen, and the open containers of splendid attire solid metal fluorochemical is set on described smelting pot lower inner wall and/or the described thermoscreen lower surface.
The present invention is by filling the solid metal fluorochemical that has higher vapor pressure under the smelting temperature in smelting furnace, by inflation inlet in smelting pot, charge into carrier gas or and Air mixing gas, realize preventing the purpose of magnesium alloy evaporation and oxidizing fire.Whole fusion process does not need to charge into the fluorine-containing shielding gas of the high-temperature chamber effect that current magnesium industry uses or contains poisonous SO
2Shielding gas.That the present invention has is low to the smelting pot seal request, saving, economy, environmental protection, can effectively prevent magnesium alloy from oxidative combustion, operation interface close friend's characteristics, and therefore, the utmost point has application value.
Description of drawings
Fig. 1 is the one-piece construction synoptic diagram of magnesium alloy sealing smelting furnace.
Embodiment
Below in conjunction with accompanying drawing the present invention is described in further details.
Fig. 1 has shown a specific embodiment of magnesium alloy sealing smelting furnace of the present invention, comprise smelting pot 1, be used for the process furnace 12 of heating melting crucibles, charge into the gas input device (not shown) of gas by the inflation inlet on the smelting pot 1 10, be arranged on tensimeter 8 and temperature thermocouple 7 on the smelting pot lid 9, vacuum system (not shown) that is used to discharge gas in the smelting pot that is communicated with by venting port 11 with crucible top and the oxygen concentration analyser 5 that is used to detect oxygen concentration in the smelting pot that is arranged on crucible top.
Smelting pot 1 is divided into crucible bottom 1b and crucible top 1a by thermoscreen 3, and crucible bottom 1b is positioned at process furnace 12 burner hearths, plays the melting magnesium alloy; Crucible top 1a is positioned at outside the process furnace 12, plays frozen iron fluorochemical steam, also works to hold required air in the fusion process.Be respectively arranged with the open containers 6a and the 6b of splendid attire solid metal fluorochemical on smelting pot bottom 1a inwall and thermoscreen 3 lower surfaces.
The ratio of the cylinder volume of crucible top 1a and the cylinder section area of crucible bottom 1b is more than or equal to 1; thereby guaranteed that the liquid magnesium alloy surface forms the amount of the required reaction oxygen of protective membrane; can satisfy oxygen again and only react, not with the undue concentration requirement of reacting of smelting pot inwall with magnesium liquid.
Smelting pot 1 and its crucible cover 9 and other all and the sealing of smelting pot connection portion (for example the silicon rubber loop sealing means is adopted in the connection portion), to reach resistance to air loss requirement in the stove: the voltage rise rate was smaller or equal to 100000Pa/ minute.This makes whole fusion process under discontinuous feeding gas situation, and oxygen concentration is in the scope of safety melting in the stove.
The body of heater of process furnace generally adopts circular configuration, and the silicon carbide liner adds refractory brick and rock wool heat-preservation, and smelting furnace adopts resistance wire to heat outside smelting pot usually.Temperature thermocouple 7 is by in the magnesium liquid in the insertion of the aperture on the crucible cover smelting pot bottom 1b.
Described vacuum system is used to get rid of original state air in the smelting pot, and the vacuum pump, partition vacuum valve and the vacuum-lines that are lower than 1Pa by final vacuum are formed; Gas input device comprises under meter, tensimeter, gas storage steel cylinder and gas circuit composition, is used for charging in smelting pot the mixed gas of carrier gas or carrier gas and air, prevents oxidation in the magnesium liquid fusion process, burning.
Describe in detail below and utilize above-mentioned magnesium alloy sealing smelting furnace to prevent the method for liquid magnesium alloy oxidizing fire, described method comprises the steps:
Initiating process: earlier crucible cover 9 is removed, the furnace charge of drying is added the smelting pot bottom of magnesium alloy sealing smelting furnace; And the solid metal fluorochemical that will dry puts into the open containers 6a on the smelting pot lower inner wall, perhaps among the open containers 6b on the thermoscreen lower surface, perhaps among the 6c of smelting pot bottom, covers thermoscreen 3 and smelting pot lid 9 afterwards.Wherein, described solid metal fluorochemical be under the magnesium alloy smelting temperature vapour pressure greater than 10
-4The metal fluoride of handkerchief is as MgF
2Or AlF
3Deng.The amount of putting into of the metal fluoride of smelting pot is to be determined jointly by smelting pot volume and magnesium alloy quality to be melted.The amount of putting into of preferable alloy fluorochemical (is unit with the mole fluorine atom) is the numerical value of volume (with the unit of being upgraded to) of smelting pot and the numerical value sum of magnesium alloy quality (is unit with the kilogram) to be melted at least, again divided by 30.
Open vacuum system then, get rid of the air in the smelting pot 1; When crucible 1 internal pressure underspeeds less than 0.2Pa/ minute, close the vacuum system that links to each other with smelting pot 1 and cut off valve, open inflation inlet, utilize gas input device in smelting pot 1, to charge into carrier gas by inflation inlet 10, perhaps carrier gas and AIR MIXTURES, described carrier gas is N
2, one or more the miscellany among Ar, He, Ne or the Xe.When the smelting pot internal pressure is 7 * 10
4～1.01 * 10
5During Pa, close inflation inlet, open the process furnace power supply, beginning melting magnesium alloy; Open heating power supply also can bleed or gas replenishment process in carry out.Charge into smelting pot internal pressure 7 * 10
4～1 * 10
5Pa, it is selected according to being smelting pot voltage rise rate size, and when the smelting pot poor air-tightness, i.e. smelting pot voltage rise rate is 30000～100000Pa/ minute, charges into the shielding gas pressure-controlling in the crucible 1.01 * 10
5Pa; When smelting pot voltage rise rate less than 30000Pa/ minute, charge into the shielding gas pressure-controlling in the crucible 7 * 10
4Pa.
Fusion process: utilize tensimeter to detect the interior pressure of smelting pot in real time, the control furnace pressure is in safety range; Utilize the oxygen concentration analyser to monitor the content of oxygen in the stove in real time, guarantee that oxygen partial pressure is 1 * 10 in the stove
2～8 * 10
3Pa.
When the smelting pot poor air-tightness, i.e. smelting pot voltage rise rate is 30000～100000Pa/ minute, before melting begins, guarantees that by the method for inflating while bleeding oxygen partial pressure is 1 * 10 in the stove
2～8 * 10
3Pa; In the fusion process, oxygen partial pressure surpasses 8 * 10 in the stove
3During Pa, feeding carrier gas oxygen partial pressure to the furnace atmosphere in stove is 4 * 10
3Pa; In the fusion process, oxygen partial pressure is lower than 1 * 10 in the stove
2During Pa, bubbling air oxygen partial pressure to the furnace atmosphere is 4 * 10 in stove
3Pa prevents magnesium alloy evaporation or oxidizing fire, and so operation moves in circles.
When the smelting pot resistance to air loss is good, i.e. smelting pot voltage rise rate charged into the gas pressure-controlling about 7 * 10 less than 30000Pa/ minute in the crucible
4Pa.In the heat temperature raising process, if described oxygen partial pressure is lower than ultimate value 1 * 10 in the smelting pot
2, then in smelting pot, charge into air, reach 4 * 10 until oxygen partial pressure
3Pa, thus magnesium alloy evaporation or oxidizing fire prevented, and so operation moves in circles.
Below to fill solid metal fluorochemical MgF
2Or AlF
3Be example, the method that prevents magnesium alloy from oxidative combustion is described, the device of employing is a magnesium alloy sealing smelting furnace of the present invention.
Crucible cover 9 is removed, with the solid metal fluorochemical MgF of drying
2(35 gram) adds among the open containers 6a on the smelting pot lower inner wall, and the furnace charge (5 kilograms) of drying is added crucible bottom 1b, covers thermoscreen 3 and smelting pot lid 9 afterwards.Open vacuum system then, get rid of the air in the smelting pot 1; When crucible 1 internal pressure underspeeds less than 0.2Pa/ minute, open inflation inlet, continued to bleed 3 minutes, utilize the shielding gas input unit in smelting pot 1, to charge into carrier gas N simultaneously by inflation inlet 10
2When furnace pressure is 1 * 10
5During Pa, close inflation inlet, close vacuum pump, open the process furnace power supply, beginning melting magnesium alloy.
In the fusion process, utilize tensimeter and oxygen concentration analyser to detect crucible interior pressure and concentration of oxygen in real time, if oxygen partial pressure is less than 1 * 10 in the smelting pot
2Pa, charging into air oxygen partial pressure to the stove in smelting pot once more is 4 * 10
3Pa.After this, so operation moves in circles.
Example 2, fusing magnesium alloy AZ91D, 30 liters of volumes, 680 ℃ of smelting temperatures, smelting pot voltage rise rate 20Pa/ minute does not have air in the shielding gas intake line.
Crucible cover 9 is removed, with the solid metal fluorochemical MgF of drying
2(totally 34 grams) add respectively among the open containers 6a and the open containers 6b on the thermoscreen lower surface on the smelting pot lower inner wall, and the furnace charge (4 kilograms) of drying is added crucible bottom 1b, cover thermoscreen 3 and smelting pot lid 9 afterwards.Open vacuum system then, get rid of the air in the smelting pot 1; When crucible 1 internal pressure underspeeds less than 0.2Pa/ minute, close the vacuum system that links to each other with smelting pot 1 and cut off valve.Open inflation inlet, utilize gas input device in smelting pot 1, to charge into 80%N by inflation inlet 10
2+ 20% air is effectively to prevent evaporation in the magnesium liquid fusion process, oxidation, burning, when the smelting pot internal pressure is about 7 * 10
4The time, close inflation inlet, open the process furnace power supply, beginning melting magnesium alloy.
Example 3, fusing magnesium alloy AZ91D, 30 liters of volumes, 680 ℃ of smelting temperatures, smelting pot voltage rise rate 2000Pa/ minute does not have air in the shielding gas intake line.
Crucible cover 9 is removed, with the solid metal fluorochemical AlF of drying
3(totally 33 gram) adds respectively among the open containers 6a (30 gram) and smelting pot bottom 6c (3 gram) on the smelting pot lower inner wall, and furnace charge (3 kilograms) the adding crucible bottom 1b with dry covers thermoscreen 3 and smelting pot afterwards and covers 9.Open vacuum system then, get rid of the air in the smelting pot 1; When crucible 1 internal pressure underspeeds less than 0.2Pa/ minute, close the vacuum system that links to each other with smelting pot 1 and cut off valve.Open inflation inlet, utilize gas input device in smelting pot 1, to charge into the 80%Ar+20% air, effectively to prevent evaporation in the magnesium liquid fusion process, oxidation, burning, when the smelting pot internal pressure is about 7 * 10 by inflation inlet 10
4The time, close inflation inlet, open the process furnace power supply, beginning melting magnesium alloy.
In the fusion process, utilize tensimeter and oxygen concentration analyser to detect crucible interior pressure and concentration of oxygen in real time, if oxygen partial pressure is less than 1 * 10 in the smelting pot
2Pa, charging into air oxygen partial pressure to the stove in smelting pot once more is 4 * 10
3Pa.After this, so operation moves in circles.
That utilizes that the present invention proposes prevents from the method for magnesium alloy from oxidative combustion to have solved the SF that current magnesium industry circle uses the high-temperature chamber effect with the solid metal fluorochemical
6Or poisonous SO
2The harm that brings does not need to charge into continuously shielding gas at the fusion process of whole magnesium alloy, and the general melting middle and later periods only needs disposable charging in the stove.Can realize the low harm ground melting magnesium alloy that pollutes, hangs down.
Claims (4)
1. prevent the method for liquid magnesium alloy oxidizing fire, it is characterized in that described method comprises the steps:
Initiating process: the furnace charge that will dry adds the smelting pot bottom of magnesium alloy sealing smelting furnace, and the solid metal fluorochemical that will dry puts into the open containers on smelting pot lower inner wall and/or the thermoscreen lower surface, described solid metal fluorochemical be under the magnesium alloy smelting temperature vapour pressure greater than 10
-4The metal fluoride of handkerchief, described solid metal fluorochemical is magnesium fluoride or aluminum fluoride; Utilize vacuum system to get rid of the interior air of smelting pot then, when gaseous tension in the crucible underspeeds less than 0.2Pa/ minute, close vacuum pump; Open inflation inlet, utilize gas input device in smelting pot, to charge into gas by inflation inlet, described gas be under melting condition not with the carrier gas of magnesium liquid reaction, or the mixed gas formed of carrier gas and air, wherein said carrier gas is N
2, one or more the miscellany among Ar, He, Ne or the Xe; When the smelting pot internal pressure is 7 * 10
4Pa～1.01 * 10
5During Pa, close inflation inlet, open the process furnace power supply, beginning melting magnesium alloy;
Fusion process: utilize tensimeter to detect the interior pressure of smelting pot in real time, the control furnace pressure; Utilize the oxygen concentration analyser to monitor the content of oxygen in the stove in real time, guarantee that oxygen partial pressure is 1 * 10 in the stove
2～8 * 10
3Pa.
2. the method that prevents magnesium alloy from oxidative combustion according to claim 1 is characterized in that: in initiating process, the solid metal fluorochemical of also another part being dried is put into the smelting pot bottom.
3. the method that prevents magnesium alloy from oxidative combustion according to claim 1 and 2 is characterized in that: the amount of putting into of the metal fluoride of smelting pot is to be determined jointly by smelting pot volume and magnesium alloy quality to be melted.
4. one kind at the described magnesium alloy sealing smelting furnace that prevents to use in the method for liquid magnesium alloy oxidizing fire of claim 1, comprise smelting pot, be used for the process furnace of heating melting crucibles, charge into the gas input device of gas by the inflation inlet on the smelting pot to smelting pot, and oxygen concentration analyser in tensimeter on the bell and the stove, it is characterized in that: described smelting pot is divided into crucible bottom and crucible top by thermoscreen, and the open containers of splendid attire solid metal fluorochemical is set on described smelting pot lower inner wall and/or the described thermoscreen lower surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100894989A CN100404711C (en) | 2006-06-30 | 2006-06-30 | Method for preventing liquid magnesium alloy from oxidation combustion and hermetic magnesium alloy smelting furnace |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100894989A CN100404711C (en) | 2006-06-30 | 2006-06-30 | Method for preventing liquid magnesium alloy from oxidation combustion and hermetic magnesium alloy smelting furnace |
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| Publication Number | Publication Date |
|---|---|
| CN1876858A CN1876858A (en) | 2006-12-13 |
| CN100404711C true CN100404711C (en) | 2008-07-23 |
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|---|---|---|---|
| CNB2006100894989A Expired - Fee Related CN100404711C (en) | 2006-06-30 | 2006-06-30 | Method for preventing liquid magnesium alloy from oxidation combustion and hermetic magnesium alloy smelting furnace |
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Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1584074A (en) * | 2004-05-24 | 2005-02-23 | 重庆镁业科技股份有限公司 | Magnesium or magnesium alloy smelting protective method and apparatus thereof |
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2006
- 2006-06-30 CN CNB2006100894989A patent/CN100404711C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1584074A (en) * | 2004-05-24 | 2005-02-23 | 重庆镁业科技股份有限公司 | Magnesium or magnesium alloy smelting protective method and apparatus thereof |
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|---|---|
| CN1876858A (en) | 2006-12-13 |
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