• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:
    1492126 Purifying aluminium UNION CARBIDE CORP 30 Oct 1975 [8 Nov 1974] 44823/75 Heading C7D Alkali metal impurities are removed from molten Al by injecting a gas mixture of a gas inert to Al, and Cl 2 , F 2 , halogen-containing compound or a mixture of two or more of these. Suitable halogen compounds are CCl 4 , CHCl 3 , C 2 Cl 2 F 4 , and CCl 2 F 2 . Preferred mixtures are Cl 2 /N 2 and Cl 2 /Ar. The gas mixture is fed through line 11 to rotary gas injector 2 which distributes the gas in the form of fine bubbles through the Al melt 4. Effluent gas, removed at 6, is monitored by sensing device 8 for AlCl 3 in the effluent, the amount of e.g. Cl 2 in the gas mixture being controllable. In Examples, the Na content of an Al melt is reduced from 40ppm- 1ppm by a gas mixture of 4 vol per cent Cl 2 -96 vol per cent N 2 (Example 1), and by Cl 2 /Ar in which the Cl 2 content is progressively reduced from 8%-1% (by vol.) dependent upon a predetermined limit of AlCl 3 in the effluent, (Example 2).
    公开号:SU1022664A3
    申请号:SU752186412
    申请日:1975-11-06
    公开日:1983-06-07
    发明作者:Геза Чекели Эндрю
    申请人:Юнион Карбид Корпорейшн (Фирма)；
    IPC主号:
    专利说明:

    The invention relates to non-ferrous metallurgy, c. Specifically, methods for removing alkali metal impurities from molten aluminum. Alkali metals and calcium are mostly harmful impurities in aluminum alloys of intended use. Sodium is especially harmful if it has not previously been removed, hydrogen in the alloy. It is necessary that the sodium content in an aluminum alloy containing more than 1% of magnesium be kept below 0.0005%. The presence of lithium in aluminum is also undesirable, since it causes corrosion of aluminum foil in humid air. Alkali metals enter aluminum in electrolyzers during the electrolytic reduction of alumina in the presence of cryolite. A known method of refining alumina from an alkali metal impurity, including preparing a tank for refining aluminum, introducing molten aluminum into the reservoir before adding the alloying components, to synchronize the melt with refining gas in the form of discrete bubbles consisting of a mixture of 11.0 vol. % chlorine and gas, inert with respect to aluminum, for a period of time sufficient for. lowering the concentration of impurities aluminum in aluminum to the required level, and removal of the reaction products. The content of active gas (chlorine) in the mixture during the refining process is kept constant, -. The disadvantage of this method is the emission of corrosive and toxic gases and vapors. These gases contain mostly unreacted chlorine, aluminum chloride, vapor: Neither hydrochloric acid and alumina evaporation (the last two compounds are formed during the hydrolysis of the gaseous alkoline chloride). In magnesium-containing alloys, the reaction of chlorine with magnesium is more preferable than the reaction with sodium, especially in low sodium concentrations. The high affinity of chlorine for magnesium causes serious difficulties. production of high-purity metal, especially in high-alloyed alloys. Thus, large amounts of chlorine must react (with these alloys with large amounts of gas compared to the amount required for stoichiometric removal of sodium. Such excess chlorine is not only not needed, but also directly responsible for the emission of contaminants and for the loss of magnesium from the alloy. The purpose of the invention is to reduce gas consumption and reduce the amount of harmful emissions into the atmosphere. The goal is achieved by the method of refining aluminum from alkali metal impurities, including a vacuum for refining aluminum, adding molten aluminum to the tank by adding alloying components, contacting the molten aluminum with a refining gas in the form of discrete bubbles consisting of a mixture of 1-10% by volume of chlorine and gas that is inert with respect to aluminum for a period of time, sufficient to lower the concentration of the alkali metal impurity in aluminum mines to the required level, and the removal of the reaction products, the concentration of chlorine in the gas mixture decreases as the content of alkali metal impurities in the Luminos, wherein the ratio of alkali metal atoms per mole of the halogen (chlorine) in the reaction products is maintained in the range of from 1.5 to 2, O. I -. A method for removing alkali metal impurities from aluminum, which basically prevents harmful gases and vapors from escaping into the environment, includes the following steps: preparing a tank for treating molten aluminum equipped with devices for introducing gas into molten aluminum and devices for withdrawing reaction products; introducing molten aluminum into the tank before adding any alloying components; the introduction of a refining gas containing a mixture of a gas selected from a group including chlorine, fluorine, halogen-containing compounds and their mixtures, and a gas inert relative to aluminum, into a molten bath in the form of discrete well-distributed gas bubbles so that said gas bubbles enter into intimate contact with the entire mass of molten alnmini; maintaining the halogen concentration in the specified refining gas at such a value that as the concentration of alkali metal impurities in the melt decreases, a sufficiently high selective halogenization of these impurities relative to aluminum at any level of alkali metal impurities will be ensured; maintaining the flow of said refining gas in molten aluminum for a period of time sufficient to lower: Co-concentration of alkali metal impurities in aluminum to the required level. Thus, the essence of the invention is that the chlorine concentration in the inert gas mixture is continuously responsive to a decrease in the sodium content in the melt so that at any given level of impurities the gas mixture is optimally concentrated for selectively chlorinating sodium relative to aluminum with simultaneous reduction amount of inert gas. The refining gas dispersed inside the melt contains a mixture of inert gas and halogen and / or halogen-containing compound, which can chemically react with alkali metals at the temperature of the molten aluminum. Nitrogen and argon are predominant inert gases, and chlorine and fluorine are predominant halogens ;. The term halogen-containing compound refers to those Halogen compounds that can either directly react with alkali or metals, or create gaseous g / jugen during decomposition at the temperature of the molten aluminum. : for example, CC. GHCli. . Figure 1 shows a graph of the dependence of the sodium chlorination selectivity in an alkaline melt on the concentration of sodium (Cdc) in the melt for one-time different concentration of chlorine in the refining gas (the ordinate axis shows the value of the sodium chloride and alklime ratio in the reaction products formed during the chlorine interaction in a melting at 4) f in Fig. 2, a six-step programmed decrease in the concentration of chlorine in the gas with a decrease in the atomic co-concentration of sodium in. aluminum from 40-10 to this concentration of aluminum chloride in the output gas is maintained below a predetermined level. The curves shown in FIG. 1 represent gas mixtures used for melt refining, having chlorine concentrations of 10% by volume or less. As can be seen from the graph, chlorine reacts predominantly with sodium at high concentrations of sodium, but this advantage rapidly decreases at low concentrations. The GwHocTb and the puber is based on the TBM fact that a decrease in sodium chlorination selectivity can be effectively compensated by reducing the chlorine concentration in the gas mixture. So. a decrease in chlorine concentration from 10 to 1 vol% increases the selectivity of sodium chlorination by about three times. This improvement in selectivity is especially important at low sodium concentrations. For example, at Cd 5-1 (about 4 sodium atoms per 1 aluminum atom are removed from the melt when refining is carried out with a mixture containing 10% chlorine (Fig. 1), i.e., the ratio N aCI / AlCIj in the reaction products is 4., and the ratio of sodium atoms per mole of chlorine is about 1.11. When refined with a mixture containing 1% chlorine, the ratio of NaCl / AlCjj increases to 11, and the ratio of Na / Cl2 in the reaction products is 57. Thus, the removal of sodium from the melt is faster than aluminum, when using low concentrations of chlorine in the refining gas, in the In this case, effective use of chlorine is achieved while at the same time suppressing the formation of aluminum chloride gas. In addition, a decrease in the concentration of aluminum chloride in the output of the gas with a decrease in the concentration of chlorine in the refining gas is not only a dilution, but due to the fact that at low concentrations The chlorine preferentially reacts with sodium, and as a result, the formation of alcmini chloride is reduced. A reduction in gas consumption can be achieved (Fig. 2) by treating the metal with a refining gas of variable composition so that the chlorine concentration in the gas is maintained at the highest possible level, thereby increasing the selective chlorination of sodium. At the same time, the conditions are maintained so that the concentration of aluminum chloride in the reaction products does not exceed a predetermined level. Figure 2 shows the curves showing the need for refining gas to reduce the concentration of sodium in the aluminum melt from 40-10 to the required values at fixed values of C in the gas. The family of curves located on the right side of the diagram is a correlation between the excess chlorine in the gas mixture, which does not react with sodium during refining, and the sodium concentration in the melt, unreacted with sodium chlorine in the form of AlCl fraction. -j in the exit gas (ascending scale above figure 2). As can be seen from these curves, the greater the chlorine concentration in the mixture, the greater the molar fraction of AlCl in the reaction products is any specific sodium content in the melt, or as the sodium content in the melt decreases when the melt is treated with a gas with a fixed concentration of chlorine in the concentration of alkyne chloride in the melt -, the reaction items are increased. The advantage of the invention lies in the optimal refining process by changing the concentration of chlorine in the gas mixture.
    Example. The sodium content in the aluminum melt decreases from 40-10 to 1 "1 (1 atm, with a stepwise decrease in the concentration of hlsra in the refining gas, in which the inert carrier is argon. The specified limit of L of the aluminum chloride from the Bath is 0.043% by volume in In Fig. 2, the given level of emission is represented by a vertical line running across the curve family from the right side of the diagram with En-7.75 (corresponding to an aluminum chloride molar fraction of 0.00043). Refining gas is introduced into the molten bath metal in shape well As indicated by the horizontal arrows in Fig. 2, the refining of the aluminum bath is carried out with a gas mixture containing 8% chlorine, and continues until: until the specified limit of aluminum chloride in the output gas is reached. sodium chi in the metal is: - 16.6., and the ratio Na / C in the reaction products is 1/95. From the curves located on the left side, fig. 2, it can be seen that the consumption of a mixture containing 8% chlorine gas, a lowering level of sodium from 40 - 10 to 16.6-10 is 0.13 aluminum. Then, the supply of a gas mixture containing 8% chlorine is stopped, and the mixture is introduced into the melt; 6% chlorine until the limit of AlCl concentration in the output
    gas, corresponding to the CVit 14-10 I
    associated; ; 14-10 ® in the melt. The ratio, Na / CIj in the reaction products is thus 1.92. The chlorine concentration in the mixture is then reduced to 4% and the process is again repeated by continuously replacing the gas mixture containing successively decreasing chlorine content (i.e. 3%, 2%: and 1% chlorine at 10; 7.6 and: 4, 610-, respectively) until noka the final concentration is reached. The sodium is lower than the ratio Ma / CI in the reaction products for these points is l, 86jl, 75 and 1.46, respectively. The total gas flow rate during the entire refining process is indicated on the lower abscissa scale. In general, about 0.65 m of gas per ton of metal 1 is required to reduce the concentration of sodium in the metal from 40-10 to 1-10 when processing molten aluminum using the proposed method.
    The programmed refining scheme does not necessarily have to be carried out with a finite number of stages or stages. The chlorine content in the mixture can be reduced in a continuous manner. For example, the chlorine concentration in a gas can be reduced automatically in response to readings from a sensitive device, which measures the concentration of pollutants in the outgoing gas and continuously maintains the composition of the refining gas at an optimum level.
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    权利要求:
    Claims (1)
    [1]
    METHOD FOR REFINING ALUMINUM FROM AN ALKALINE METAL IMPURITY, which includes preparing a tank for refining aluminum, introducing molten aluminum into the tank by adding alloying components, contacting the aluminum melt with refining gas in the form of discrete bubbles, consisting of <a mixture of 1-10 vol.% Chlorine and gas, inert with respect to aluminum,. 'for a period of time sufficient to lower the concentration, bring the alkali metal in aluminum to the required level, and the product is diverted. reaction, characterized in that, in order to reduce gas consumption and reduce the amount of harmful emissions into the atmosphere, the concentration of chlorine in the gas mixture is reduced as the content of alkali metal impurities in aluminum decreases, while the ratio of alkali metal atoms per mole of halogen in the reaction products support in the range from 1.5 to 2.0;
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    同族专利:
    公开号 | 公开日
    AT348770B|1979-03-12|
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    DE2544854B2|1976-08-26|
    SE7512510L|1976-05-10|
    JPS585975B2|1983-02-02|
    FR2290500A1|1976-06-04|
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    IT1052174B|1981-06-20|
    YU39752B|1985-04-30|
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    AU8640475A|1977-05-12|
    YU282875A|1982-06-30|
    ATA848275A|1978-07-15|
    FR2290500B1|1980-05-09|
    IN144890B|1978-07-22|
    DE2544854A1|1976-05-13|
    CA1046286A|1979-01-16|
    NO139969B|1979-03-05|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR1130492A|1954-05-13|1957-02-06|Aluminum Co Of America|Improved method and apparatus for degassing and purifying molten metals containing aluminum|
    US3087808A|1960-07-28|1963-04-30|Chemetron Corp|Process for cleaning and degassing molten aluminum and aluminum alloys|
    GB1282263A|1970-01-09|1972-07-19|British Oxygen Co Ltd|Purification of aluminium|
    GB1428146A|1972-09-18|1976-03-17|Aluminum Co Of America|Purification of aluminium|
    US3839019A|1972-09-18|1974-10-01|Aluminum Co Of America|Purification of aluminum with turbine blade agitation|DE2818495B1|1978-04-27|1979-10-04|Hans Horst Schmelz Und Giesste|Process for melting aluminum or aluminum alloys in an induction channel melting furnace|
    FR2502181B1|1981-03-23|1985-09-27|Servimetal|PROCESS AND APPARATUS FOR THE PRECISE AND CONTINUOUS INJECTION OF A HALOGENATED DERIVATIVE IN A GASEOUS STATE IN A LIQUID METAL|
    US4350524A|1981-05-15|1982-09-21|Kennecott Corporation|Process for removal of base metal impurities from molten silver with sulfur hexafluoride|
    FR2514370B1|1981-10-14|1989-09-29|Pechiney Aluminium|DEVICE FOR THE TREATMENT, ON THE PASSAGE, OF A STREAM OF METAL OR LIQUID ALLOY BASED ON ALUMINUM OR MAGNESIUM|
    US4392888A|1982-01-07|1983-07-12|Aluminum Company Of America|Metal treatment system|
    JPS59129726U|1983-02-21|1984-08-31|
    JPH0333661Y2|1983-11-01|1991-07-17|
    JPH0253496B2|1984-09-26|1990-11-16|Honsel Werke Ag|
    US4521001A|1984-10-11|1985-06-04|Honsel-Werke Ag|Apparatus for removing gases from molten metal, especially molten aluminum|
    GB8428251D0|1984-11-08|1984-12-19|Alcan Int Ltd|Treating aluminium|
    DE3564449D1|1984-11-29|1988-09-22|Foseco Int|Rotary device, apparatus and method for treating molten metal|
    GB8622458D0|1986-09-18|1986-10-22|Alcan Int Ltd|Alloying aluminium|
    US4959101B1|1987-06-29|1992-02-25|Aga Ab|
    US5085830A|1989-03-24|1992-02-04|Comalco Aluminum Limited|Process for making aluminum-lithium alloys of high toughness|
    US5029821A|1989-12-01|1991-07-09|The Carborundum Company|Apparatus for controlling the magnesium content of molten aluminum|
    US5090998A|1989-12-20|1992-02-25|Alusuisse-Lonza Services Ltd.|Purification of metal melts with halogen gas generated in an electrolysis cell|
    US4992241A|1990-03-15|1991-02-12|Alcan International Limited|Recycling of metal matrix composites|
    DE102017110947A1|2017-05-19|2018-11-22|Illinois Tool Works Inc.|Device for fastening to a bolt of a carrier component|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    US05/522,143|US3958980A|1974-11-08|1974-11-08|Process for removing alkali-metal impurities from molten aluminum|
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