JPH0790407A - Method for refining aluminum - Google Patents
Method for refining aluminumInfo
- Publication number
- JPH0790407A JPH0790407A JP5234897A JP23489793A JPH0790407A JP H0790407 A JPH0790407 A JP H0790407A JP 5234897 A JP5234897 A JP 5234897A JP 23489793 A JP23489793 A JP 23489793A JP H0790407 A JPH0790407 A JP H0790407A
- Authority
- JP
- Japan
- Prior art keywords
- aluminum
- molten
- solidification
- magnetic field
- impurity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、ボーキサイトを溶融
塩電解して得られる普通純度アルミニウムをより高純化
すること、アルミニウム２次地金を展延材として再利用
するため高純化することなど、高純度アルミニウムを得
るためのアルミニウムの精製方法を提案するものであ
る。BACKGROUND OF THE INVENTION The present invention relates to the purification of ordinary-purity aluminum obtained by electrolysis of bauxite by molten salt, the purification of aluminum secondary metal for reuse as a spreading material, and the like. An aluminum refining method for obtaining high-purity aluminum is proposed.
【０００２】通常、アルミニウムはボーキサイト(Al
2O3) を溶融塩電解することで得られる。このようにし
て得られるアルミニウム地金は、通常99.7〜99.8％の純
度を有し、加工性が良いこと、軽量化が図れることなど
から自動車の車体用材や缶用材として利用されている。
さらに、99.9〜99.99 ％の高純度アルミニウムが電解コ
ンデンサーの陽極箔やエレクトロニクス分野の装置主要
部材として用いられている。また、最近では資源の有効
利用の観点から、不純物の多いアルミニウムスクラッ
プ、さらにはアルミニウム２次地金の高純化再利用が注
目されている。Usually, aluminum is bauxite (Al
2 O 3 ) is obtained by electrolysis of molten salt. The aluminum metal thus obtained is usually used as a material for automobile bodies and cans because it has a purity of 99.7 to 99.8%, good workability, and light weight.
In addition, 99.9-99.99% high-purity aluminum is used as the anode foil of electrolytic capacitors and as a major component of electronic equipment. Further, recently, from the viewpoint of effective use of resources, attention has been paid to aluminum scrap containing a large amount of impurities, and further, highly purified reuse of secondary aluminum ingot.
【０００３】このような背景のもと、低純度のアルミニ
ウム地金やアルミニウムスクラップを高純度アルミニウ
ム地金や展伸用合金、鋳物用合金原料として再利用する
ことをねらいとして、安価で、作業性のよい高純化方法
が模索・検討されている。たとえば、自動車車体用で
は、アルミニウム純度99.9％程度、他の一般シート用材
でも99％程度までの純化が望まれていて、これがアルミ
ニウムスクラップから安価に精製できれば大きな需要が
期待できる。Against this background, low-purity aluminum ingots and aluminum scraps are inexpensive and workable with the aim of reusing high-purity aluminum ingots, wrought alloys, and casting alloy raw materials. A good purification method is being sought and considered. For example, for automobile bodies, it is desired to purify aluminum to about 99.9% and other general sheet materials to about 99%. If this can be refined from aluminum scrap at low cost, great demand can be expected.
【０００４】[0004]
【従来の技術】前記したようなニーズに対処するための
アルミニウムの純化技術に関してはこれまでに種々の手
段が提案されているが、それらの一つに、アルミニウム
溶湯が凝固する際の不純物溶質成分（以下単に不純物又
は不純物成分という）の偏析現象を利用する方法があ
る。2. Description of the Related Art Various techniques have been proposed so far with respect to the aluminum purification technique for addressing the above-mentioned needs. One of them is the impurity solute component when the molten aluminum is solidified. There is a method of utilizing the segregation phenomenon of (hereinafter simply referred to as impurities or impurity components).
【０００５】すなわち、上記方法は、成分濃度が増加す
るにつれて液相線、固相線を低下させるFe, Si等を不純
物として含有するアルミニウム溶湯が凝固する際、熱力
学的安定性の相違から固相側では不純物成分が減少する
反面、液相側では不純物成分が増加し、そして、凝固が
進行するにつれて液相側に不純物成分の濃化する偏析現
象を生じることを利用し、固相側に純化したアルミニウ
ムを得るものである。That is, according to the above method, when the molten aluminum containing Fe, Si, etc. as impurities, which lowers the liquidus and solidus as the component concentration increases, is solidified due to the difference in thermodynamic stability. The impurity component decreases on the phase side, while the impurity component increases on the liquid phase side, and the segregation phenomenon in which the impurity component concentrates on the liquid phase side occurs as the solidification progresses. This is to obtain purified aluminum.
【０００６】上記偏析現象は、固液界面の液相側に最高
濃度ＣM 、液相バルク側に最低濃度ＣO となる不純物成
分の濃度分布が形成される。そして、固相側に取り込ま
れる不純物成分の濃度ＣS は、 ＣS ＝Ｋeff ＣO ------（１） Ｋeff ＝ＫO ／〔ＫO ＋（１−ＫO ）exp （−Ｒδ／Ｄ）〕----（２） ここで ＣM , ＣS , ＣO ：不純物成分濃度 (mol／ｍ3) Ｋeff ：実効分配系数（−） ＫO ：平衡分配系数（−） Ｒ ：凝固速度（ｍ／sec) Ｄ ：不純物成分の溶融Al中での拡散系数（ｍ2 ／se
c) δ ：不純物成分の濃度境膜層厚（ｍ） で決まる（例えば、日本金属学会編、「金属便覧 改定
３版」，丸善，（昭和46−６−25）, ｐ1162）。このこ
とは、アルミニウムの純化がアルミニウム溶湯の攪拌流
速によって定まる不純物成分の濃度境膜層厚δとアルミ
ニウムの凝固速度Ｒによって決められることを意味す
る。In the segregation phenomenon, a concentration distribution of the impurity component having the highest concentration C M on the liquid phase side of the solid-liquid interface and the lowest concentration C O on the liquid phase bulk side is formed. Then, the concentration C S of the impurity component taken into the solid phase side is C S = K eff C O ------ (1) K eff = K O / [K O + (1-K O ) exp ( -Rδ / D)] ---- (2) where C M, C S, C O : impurities concentration (mol / m 3) K eff : effective partitioning system number (-) K O: equilibrium partitioning Coefficient (- ) R: Solidification rate (m / sec) D: Diffusion system number (m 2 / se) of impurity components in molten Al
c) δ: Determined by the concentration of the impurity component, the boundary layer thickness (m) (for example, edited by the Japan Institute of Metals, “Handbook of Metals Revised 3rd Edition”, Maruzen, (Showa 46-6-25), p1162). This means that the purification of aluminum is determined by the concentration boundary layer thickness δ of the impurity component and the solidification rate R of aluminum, which is determined by the stirring flow rate of the molten aluminum.
【０００７】さらにこの場合、上記のような不純物成分
濃度分布の形成に伴ない凝固条件（固液界面近傍での温
度勾配や凝固速度）によって組成的過冷状態が発生し、
これが凝固界面に樹枝状晶を生成させる。その樹枝状晶
が成長して、凝固界面近傍の不純物成分をトラップし、
アルミニウムの高純化を妨げることがある。樹枝状晶を
生成する組成的過冷の発生しない条件は、 ＣO （Ｇ／Ｒ）＞（−ｍ／Ｄ）・((１−ＫO ）／ＫO ) ------（３） ここで Ｇ：固液界面から融液に向かっての温度勾配（℃／ｍ） ｍ：液相線の勾配℃／(mol／ｍ3 ) と云われている（例えば、日本金属学会編，「金属便覧
改定３版」，丸善，（昭和46−６−25），ｐ1163) 。Further, in this case, a compositional supercooling state occurs due to the solidification conditions (temperature gradient and solidification rate near the solid-liquid interface) accompanying the formation of the impurity component concentration distribution as described above,
This produces dendrites at the solidification interface. The dendrites grow and trap the impurity components near the solidification interface,
It may hinder high purification of aluminum. The conditions under which compositional supercooling that produces dendrites does not occur are C O (G / R)> (-m / D). ((1-K O ) / K O ) ------ (3 ) Here, G: Temperature gradient from solid-liquid interface to melt (° C / m) m: Gradient of liquidus ℃ / (mol / m 3 ) (For example, edited by The Japan Institute of Metals, "Metal Handbook Revised 3rd Edition", Maruzen, (Showa 46-6-25), p1163).
【０００８】このような理論に基づいて、例えば、特公
昭50-20536号公報（金属の純化方法）には、外部加熱容
器内の原料アルミニウム溶湯をその融点近くの温度に保
持し、その溶融アルミニウムに冷却用ガス循環可能な構
造の冷却管を挿入し、その冷却管に付着生成した小結晶
のアルミニウムを容器の下部に集めて突き固め、融体と
分離することにより精製アルミニウムを得る方法が開示
されている。しかし、この方法で得られるアルミニウム
は突き固められた塊であり、そのままでは機械加工しづ
らく、またその精製の作業性が悪いなどの問題点があっ
た。On the basis of such a theory, for example, Japanese Patent Publication No. 50-20536 (metal purification method) discloses that a molten aluminum material is kept in the external heating container at a temperature close to its melting point. A method for obtaining purified aluminum by inserting a cooling pipe having a structure capable of circulating a cooling gas into the container, collecting the small-crystal aluminum adhering to the cooling pipe and consolidating it in the lower part of the container, and separating it from the melt is disclosed. Has been done. However, the aluminum obtained by this method is a lump compacted, and it is difficult to machine it as it is, and the workability of its refining is poor.
【０００９】また、特開昭57-060040 号公報（アルミニ
ウムの精製方法）には、その詳細説明によれば、溶融ア
ルミニウムに直流電流を通電すると共に外部から直流磁
界を印加するか、又は直流電流を通電することなく、回
転磁界を印加することによって、溶融アルミニウムを回
転流動させて攪拌しながら容器底部より凝固を進行さ
せ、純化したアルミニウムを得る方法が開示されてい
る。しかし、この方法では、攪拌が水平回転流動であ
り、凝固を下部（容器底面）から上方へ向けて進行させ
るため、回転流中心部近傍の固液界面での流速は著しく
遅くなり、その部分では純化されないまま、ないしは液
相側で濃化した不純物成分がそのまま固相側に取り込ま
れ、そのため凝固の進行に伴い固相側の平均不純物成分
が徐々に増加し、凝固アルミニウムの純度が低下すると
いう問題があった。Further, in Japanese Patent Laid-Open No. 57-060040 (aluminum refining method), according to its detailed description, a direct current is applied to molten aluminum and a direct magnetic field is applied from the outside, or a direct current is applied. There is disclosed a method for obtaining purified aluminum by applying a rotating magnetic field to the molten aluminum so as to rotate and flow the molten aluminum and to cause solidification to proceed from the bottom of the container while agitating without applying electricity. However, in this method, since the stirring is horizontal rotary flow and the solidification proceeds from the lower part (bottom surface of the container) to the upper part, the flow velocity at the solid-liquid interface in the vicinity of the central part of the rotary flow becomes extremely slow, and in that part, Impurity components that have not been purified or that have been concentrated on the liquid phase side are taken into the solid phase side as they are, so that the average impurity components on the solid phase side gradually increase as the solidification progresses, and the purity of solidified aluminum decreases. There was a problem.
【００１０】そして、凝固後期において純化領域と不純
物濃化領域とを明確に区分できず、その高純度領域のみ
を分離・回収することが困難であるという問題があっ
た。すなわち、容器底面から冷却すると、図３に示すよ
うなアルミニウム凝固層４が形成され、最終的には図４
（ａ）に示すような軸心部に不純物成分の多い不純物濃
度分布を有する鋳塊となるため、純化層のみを回収する
には、鋳塊軸心部の不純物濃化領域をくりぬかなければ
ならなかった。In the latter stage of solidification, the purified region and the impurity-concentrated region cannot be clearly distinguished, and it is difficult to separate and collect only the high-purity region. That is, when cooled from the bottom surface of the container, the aluminum solidified layer 4 as shown in FIG. 3 is formed, and finally the aluminum solidified layer 4 shown in FIG.
Since the ingot has an impurity concentration distribution with a large amount of impurity components in the shaft center portion as shown in (a), in order to recover only the purified layer, the impurity concentration region in the shaft center portion of the ingot must be hollowed out. There wasn't.
【００１１】ここに、図３は容器底部から凝固を進行さ
せる（上記開示例）アルミニウム精製装置の説明図で、
２は円筒状のるつぼ、３は溶融アルミニウム、４はアル
ミニウム凝固層、９は水冷板で、るつぼ２の底面を形成
している。また、図４（ａ）は容器底部から凝固を進行
させて得られた（比較例）鋳塊縦断面における不純物成
分Siの等濃度曲線を示すグラフである。FIG. 3 is an explanatory view of an aluminum refining apparatus for advancing solidification from the bottom of the container (the above disclosed example),
2 is a cylindrical crucible, 3 is molten aluminum, 4 is an aluminum solidified layer, and 9 is a water cooling plate, which forms the bottom surface of the crucible 2. Further, FIG. 4A is a graph showing an isoconcentration curve of impurity component Si in a vertical cross section of the ingot (comparative example) obtained by advancing solidification from the bottom of the container.
【００１２】さらに、上記開示例の場合、流速を増大す
るために回転流動の回転数を増加させると、溶湯面が放
物面状の深い凹面となり、下方と側方の両方から凝固が
進行し、ますます純化領域を分離回収することが困難に
なるという問題もあった。Further, in the above disclosed example, when the rotational speed of the rotary flow is increased to increase the flow velocity, the molten metal surface becomes a parabolic deep concave surface, and solidification proceeds from both the lower side and the lateral side. There is also a problem that it becomes more difficult to separate and collect the purified region.
【００１３】次に、特開昭58-11752号公報（アルミニウ
ムの精製方法）には、溶融アルミニウムを下方から凝固
させるさいに、固液界面近傍の液相中に、下面が固液界
面と対向する回転体の下面中央から気体を放出させなが
らこの回転体を回転させて、固液界面近傍の液相中の不
純物を液相全体に分散混合させつつ凝固を進行させ、純
化する方法が開示されている。しかしながら、この方法
では気体による分散の強い部分と弱い部分とが生じ、凝
固速度が速い場合には固液界面に凹凸ができ、凝固後期
において純化領域と不純物濃化領域とが明確に区別され
なく、純化領域のみを分離回収することが困難になると
いう問題があった。Next, in JP-A-58-11752 (a method for refining aluminum), when solidifying molten aluminum from below, the lower surface is opposed to the solid-liquid interface in the liquid phase near the solid-liquid interface. A method is disclosed in which the rotating body is rotated while releasing gas from the center of the lower surface of the rotating body, and the impurities in the liquid phase in the vicinity of the solid-liquid interface are dispersed and mixed throughout the liquid phase to promote solidification and purification. ing. However, in this method, a portion where the gas is strongly dispersed and a portion where the gas is dispersed are generated, and when the solidification rate is high, irregularities are formed on the solid-liquid interface, and the purified region and the impurity-concentrated region are not clearly distinguished in the latter stage of solidification. However, there is a problem that it becomes difficult to separate and collect only the purified region.
【００１４】また、溶湯は回転体の回転による水平回転
流動と気体放出による上下方向循環流動の合成流動とな
るが、上記開示例の場合と同様に回転流中心部近傍の固
液界面では流速の遅延部分が生じ、その部分では純化さ
れないまま、ないしは固液界面の液相側で濃化した不純
物成分がそのまま固相側に取り込まれ、凝固の進行と共
に固相側の平均不純物成分濃度が徐々に上昇し、凝固し
たアルミニウムの純度が低下するという問題もあった。Further, the molten metal becomes a synthetic flow of horizontal rotational flow due to the rotation of the rotating body and vertical circulating flow due to gas release. However, as in the case of the above disclosed example, the flow velocity at the solid-liquid interface near the center of the rotational flow is A delayed portion occurs, and the impurity component that is not purified in that portion or is concentrated on the liquid phase side of the solid-liquid interface is directly taken into the solid phase side, and the average impurity component concentration on the solid phase side gradually increases as coagulation progresses. There is also a problem that the purity of the solidified aluminum decreases as the temperature rises.
【００１５】[0015]
【発明が解決しようとする課題】この発明は、前記した
問題点を有利に解決すること、すなわち、 ・凝固界面に凹凸ができていないようにすること、 ・凝固の進行のどの時点においても純化領域（固相）と
不純物濃化領域（液相）とが明確に区分できること、 ・製造される鋳塊はそのまま機械加工等に適用できるも
のであること、 ・高純化工程の作業性が良いものであること、などを達
成する高純化アルミニウムの精製方法を提案することを
目的とする。SUMMARY OF THE INVENTION The present invention advantageously solves the above-mentioned problems, namely, that there is no unevenness at the solidification interface, and that purification is performed at any point during the progress of solidification. The area (solid phase) and the impurity concentration area (liquid phase) can be clearly distinguished.-The manufactured ingot can be directly applied to machining, etc.-The workability of the high purification process is good. It is an object of the present invention to propose a refining method for highly purified aluminum that achieves the following.
【００１６】[0016]
【課題を解決するための手段】この発明の要旨は以下の
通りである。回分系の円筒容器内に供給したアルミニウ
ム溶湯を、回転磁界により水平回転流動させながら、円
筒容器の側壁から冷却し、その軸心に向けて凝固を進行
させることを特徴とするアルミニウムの精製方法であ
り、さらに上記において、アルミニウムの凝固過程の中
途段階で水平回転流動を停止し、円筒容器底部に設けた
排出孔から不純物成分が濃化した残部溶湯を円筒容器外
に排出するアルミニウムの精製方法である。The summary of the present invention is as follows. A method for refining aluminum characterized in that the molten aluminum supplied into a batch-type cylindrical container is cooled from the side wall of the cylindrical container while being horizontally rotated by a rotating magnetic field, and solidification proceeds toward its axis. Yes, in the above, in the method for purifying aluminum, the horizontal rotary flow is stopped in the middle of the solidification process of aluminum, and the residual molten metal in which the impurity components are concentrated is discharged from the discharge hole provided at the bottom of the cylindrical container to the outside of the cylindrical container. is there.
【００１７】[0017]
【作用】この発明に至った経緯とその作用について以下
に述べる。この発明は、溶湯の凝固に関する前記した理
論をさらに詳細に検討した結果、凝固過程での偏析現象
を利用して、凝固時に取り込まれる不純物量をより低減
すること、かつ、凝固速度が遅い場合の樹枝状晶の生成
を低減すること、などのためには、溶湯の攪拌方法と凝
固方法の組合せおよびそれらの操作条件を工夫して、固
液界面全域にわたって不純物成分の濃度境膜層厚をでき
る限り均等に、かつ薄くすることが肝要であるとの認識
に達した。OPERATION Background of the invention and its operation will be described below. As a result of further detailed study of the above-mentioned theory regarding the solidification of molten metal, the present invention utilizes the segregation phenomenon in the solidification process to further reduce the amount of impurities taken in during solidification, and when the solidification rate is slow. In order to reduce the generation of dendrites, etc., the concentration of impurity components can be controlled across the solid-liquid interface by devising the combination of the stirring method and the solidification method of the molten metal and their operating conditions. We have come to realize that it is important to make it as even and thin as possible.
【００１８】そして、上記をもとに、溶湯の攪拌方法と
凝固方法の組合せを種々変化させた広範な実験検討を行
った結果、まず、Al溶湯の攪拌方法としては、 ａ．回転磁界によってアルミニウム溶湯に水平回転流動
を与えることが、設備的な容易さならびに単位体積当り
の攪拌力の大きさから考えて最適であること、さらに、
上記攪拌方法を採用する場合の凝固方法としては、 ｂ．溶湯表面が放物面状の凹面になることを利用して、
円筒容器の側壁からその軸心に向けて凝固を進行させる
ことで、不純物濃化溶湯を回転流動軸心方向に集中させ
得ること、 ｃ．溶湯の回転数を大きくすることで、溶湯表面の放物
面状凹面の深さΔＨ（ΔＨ＝（ｒω）2 ／２ｇ、ここで
ｒは溶湯回転流外径、ωは回転角速度、ｇは重力加速
度）をいくらでも大きくできることから、回転流動中心
近傍の容器底面には溶湯がない状態すなわち溶湯回転流
体を中空状にすることができ、底面からの凝固を防止で
きること、また、底面をヒーターで加熱して断熱するこ
とは容易であり、かくすることによっても底面からの凝
固を防止できること、 ｄ．円筒容器の側壁からその軸心に向けての凝固であ
り、溶湯が水平回転流動であるため、固液界面全面にわ
たって回転流の流速はほぼ一定で遅延部分がなく、した
がって、前記従来例のように流速の遅延部が生じ、その
部分の固液界面の純化されないままないしは液層側で濃
化した不純物成分がそのまま固相側に取り込まれること
がなく、凝固の後期においても凝固したアルミニウムの
純度が高レベルに維持できること、 ｅ．円筒状容器側壁内面で中空状の凝固層形成後に不純
物が濃化した残部溶湯の回転流動を停止させ、その不純
物濃化溶湯を容器底面に設けた排出孔から排出・分離で
きること、などが明らかとなった。Then, based on the above, as a result of extensive experiments and examinations in which the combination of the stirring method and the solidification method of the molten metal was variously changed, first, as the stirring method of the Al molten metal, a. It is optimal to give a horizontal rotary flow to the molten aluminum by a rotating magnetic field in view of the facility ease and the magnitude of the stirring force per unit volume.
As the coagulation method when the above stirring method is adopted, b. Utilizing that the surface of the molten metal becomes a parabolic concave surface,
By advancing solidification from the side wall of the cylindrical container toward its axis, the impurity-concentrated molten metal can be concentrated in the direction of the rotational flow axis, c. By increasing the number of rotations of the molten metal, the depth of the parabolic concave surface of the molten metal is ΔH (ΔH = (rω) 2 / 2g, where r is the outer diameter of the molten metal rotating flow, ω is the rotational angular velocity, and g is the gravity. Since there is no molten metal at the bottom of the container near the center of the rotating flow, that is, the molten rotating fluid can be made hollow, preventing solidification from the bottom, and heating the bottom with a heater. It is easy to insulate with heat, and by doing so it is possible to prevent solidification from the bottom surface, d. The solidification is from the side wall of the cylindrical container toward its axis, and since the molten metal is a horizontal rotary flow, the flow velocity of the rotary flow is almost constant over the entire solid-liquid interface and there is no delay portion. There is a delay in the flow velocity, and the solid-liquid interface at that portion is not purified or the impurity components concentrated on the liquid layer side are not taken into the solid phase side as they are. Can be maintained at a high level, e. After the formation of the hollow solidification layer on the inner surface of the side wall of the cylindrical container, the rotational flow of the remaining molten metal in which the impurities are concentrated can be stopped, and the molten metal in which the impurity is concentrated can be discharged and separated from the discharge hole provided on the bottom surface of the container. became.
【００１９】さらに加えて、 ｆ．溶湯の水平回転流動によって、溶湯の自由表面形状
が放物面状となるため、溶湯表面積が増加し冷却が容易
になること、すなわち、このことは前記（３）式におけ
るＧが大きな値を取り得ることを意味しており、純化を
阻害する樹枝状晶の生成を抑える効果を有すること、も
確認できた。In addition, f. Due to the horizontal rotational flow of the molten metal, the free surface shape of the molten metal becomes parabolic, which increases the surface area of the molten metal and facilitates cooling. That is, this means that G in equation (3) above has a large value. It was also confirmed that it has the effect of suppressing the formation of dendrites that impede purification.
【００２０】一方、この発明を実施するにあたって、容
器側壁内面からの凝固を進行させる方法としては、容器
側壁外面を水冷によって冷却することがよく、また、不
純物濃化溶湯の排出は、容器の底部中心に排出孔を設
け、ここから下方に不純物濃化溶湯を排出させることが
好適であるが、容器を傾転させて不純物濃化溶湯を排出
させることでもよい。On the other hand, in carrying out the present invention, as a method for advancing the solidification from the inner surface of the container side wall, the outer surface of the container side wall may be cooled by water cooling, and the molten metal enriched in impurities may be discharged at the bottom of the container. It is preferable to provide a discharge hole in the center and discharge the impurity-concentrated molten metal downward from this, but it is also possible to tilt the container to discharge the impurity-concentrated molten metal.
【００２１】以上、この発明は、回転磁界による溶湯の
水平回転流動の採用と、円筒容器の側壁からその軸心に
向けて凝固を進行させることにより、固液界面での溶湯
回転流動の流速をその全面にわたって均一にできること
が確認され、さらに固液界面での不純物溶質成分の濃度
境膜厚δが溶湯流速の１／５乗に比例することから、濃
度境膜厚δを全固液界面にわたって均等に、かつ薄くす
ることが達成できるものと推定された。As described above, according to the present invention, the horizontal rotational flow of the molten metal due to the rotating magnetic field is adopted, and the solidification is advanced from the side wall of the cylindrical container toward the axial center thereof, so that the flow velocity of the molten rotational flow at the solid-liquid interface is Since it was confirmed that the concentration boundary film thickness δ of the impurity solute component at the solid-liquid interface was proportional to the 1 / 5th power of the molten metal flow rate, the concentration boundary film thickness δ was confirmed over the entire solid-liquid interface. It was estimated that even and thinning could be achieved.
【００２２】そしてその結果として、先に掲げた ・凝固界面に凹凸ができないようにすること、 ・凝固の進行のどの時点においても純化領域（固相）と
不純物濃化領域（液層）とが明確に区分できること、 ・製造される鋳塊はそのまま機械加工等に適用できるも
のであること、 ・高純化工程の作業性が良いものであること、などを達
成することができる。As a result, the above-mentioned steps are performed so that there are no irregularities at the solidification interface, and the purification region (solid phase) and the impurity concentration region (liquid layer) are present at any point in the progress of solidification. It is possible to achieve clear classification, that the manufactured ingot can be directly applied to machining, etc., and that workability in the high purification process is good.
【００２３】[0023]
【実施例】この発明に適合する精製方法を実施するアル
ミニウム精製装置例とその実施態様の説明図を図１及び
図２に示す。これらの図において、１は回転磁界発生装
置、２はマグネシア製るつぼ（円筒容器）、３はアルミ
ニウム溶湯、４はアルミニウム凝固層、５はるつぼ３の
外周に設けたステンレス製の水冷板、６はその水冷ボッ
クス、７は底部中心に設けた排出孔、８はストッパーで
ある。1 and 2 show an example of an aluminum refining apparatus for carrying out a refining method according to the present invention and an explanatory view of its embodiment. In these figures, 1 is a rotating magnetic field generator, 2 is a magnesia crucible (cylindrical container), 3 is an aluminum melt, 4 is an aluminum solidified layer, 5 is a stainless water cooling plate provided on the outer periphery of the crucible 3, and 6 is The water cooling box, 7 is a discharge hole provided at the center of the bottom, and 8 is a stopper.
【００２４】また、図１は回転磁界発生装置１により回
転磁界を印加してアルミニウム溶湯３を水平回転流動さ
せながらるつぼ２の側壁内面からその軸心に向けて凝固
を生起させアルミニウム凝固層４を形成させた状態を示
し、図２は上記によりアルミニウム凝固層４を形成させ
たのち、回転磁界の印加を停止してアルミニウム溶湯３
の回転流動を止め、排出孔７のストッパー８を抜いた状
態を示すもので、不純物成分が濃化されたアルミニウム
溶湯３は排出孔７から排出される。Further, FIG. 1 shows that the rotating magnetic field generator 1 applies a rotating magnetic field to horizontally rotate the molten aluminum 3 and causes solidification from the inner surface of the side wall of the crucible 2 toward its axis to form the aluminum solidified layer 4. FIG. 2 shows the state in which the aluminum melt 3 has been formed, and after the aluminum solidified layer 4 has been formed as described above, the application of the rotating magnetic field is stopped.
3 shows a state in which the rotation flow of the above is stopped and the stopper 8 of the discharge hole 7 is removed. The molten aluminum 3 in which the impurity component is concentrated is discharged from the discharge hole 7.
【００２５】この発明の適合例として、上記図１に示し
た装置を用い、３kgのアルミニウム地金（アルミニウム
純度：99.7％、不純物成分----Si：0.07wt％、Fe：0.1
wt％) の溶湯３を内径：120mm のるつぼ２に供給しなが
ら、回転磁界発生装置１により回転磁界を印加してアル
ミニウム溶湯３を水平回転流動させ、水冷板５によりる
つぼ３の外周面を冷却することによって、るつぼ２の側
壁内面からその軸心に向けて凝固を生起させ、純化され
たアルミニウム凝固層４を形成させた。As a conforming example of the present invention, using the apparatus shown in FIG. 1, 3 kg of aluminum ingot (aluminum purity: 99.7%, impurity component ---- Si: 0.07 wt%, Fe: 0.1
(wt%) molten metal 3 is supplied to the crucible 2 having an inner diameter of 120 mm, a rotating magnetic field is applied by the rotating magnetic field generator 1 to horizontally rotate the molten aluminum 3, and the water cooling plate 5 cools the outer peripheral surface of the crucible 3. By doing so, solidification was caused from the inner surface of the side wall of the crucible 2 toward the axis thereof, and the purified aluminum solidified layer 4 was formed.
【００２６】上記において、アルミニウム溶湯３の回転
数は 200rpm に調整し、凝固速度は1.3 ｍ／min と一定
にした。このとき、アルミニウム凝固層４の高さは80mm
であり、図１に示すようにアルミニウム溶湯３はるつぼ
２の側壁内面に押し上げられ、るつぼ２の底部中心上に
はアルミニウム溶湯３はなく中空状を呈していた。In the above, the number of revolutions of the molten aluminum 3 was adjusted to 200 rpm, and the solidification rate was kept constant at 1.3 m / min. At this time, the height of the aluminum solidified layer 4 is 80 mm
As shown in FIG. 1, the molten aluminum 3 was pushed up to the inner surface of the side wall of the crucible 2, and the molten aluminum 3 did not exist on the center of the bottom of the crucible 2 and had a hollow shape.
【００２７】かくして、供給したアルミニウム溶湯３の
50％がアルミニウム凝固層４として形成された時点で回
転磁界の印加を停止しアルミニウム溶湯３の回転流動を
止め、ストッパ８を抜いて、残りの不純物成分が濃化し
たアルミニウム溶湯３を排出孔７から排出した。Thus, the supplied aluminum melt 3
When 50% of the aluminum solidified layer 4 is formed, the application of the rotating magnetic field is stopped to stop the rotational flow of the molten aluminum 3, the stopper 8 is pulled out, and the molten aluminum 3 in which the remaining impurity components are concentrated is discharged into the discharge hole 7 Discharged from.
【００２８】このようにして得られた鋳塊（アルミニウ
ム凝固層４）の各位置から分析用サンプルを採取し、不
純物成分のSi含有量を測定した。Samples for analysis were taken from each position of the ingot (aluminum solidified layer 4) thus obtained, and the Si content of the impurity component was measured.
【００２９】一方、容器底部から凝固を進行させる従来
方法を比較例とし、図３に示すアルミニウム精製装置に
より上記適合例の場合と同一のアルミニウム地金を用
い、容器底部から凝固を進行させアルミニウム凝固層を
形成させた以外は、上記適合例と同様の条件で鋳塊を製
造し、得られた鋳塊について上記適合例と同様の調査を
行った。On the other hand, the conventional method of advancing the solidification from the bottom of the container is used as a comparative example, and the same aluminum ingot as in the case of the above-mentioned conforming example is used by the aluminum refining apparatus shown in FIG. An ingot was produced under the same conditions as in the above-mentioned conforming example except that a layer was formed, and the obtained ingot was examined in the same manner as in the above-mentioned conforming example.
【００３０】ここに、図３は容器底部から凝固を進行さ
せるアルミニウム精製装置の説明図で、１は回転磁界発
生装置、２はるつぼ（円筒容器）、３はアルミニウム溶
湯、４はアルミニウム凝固層、９はるつぼ２の底部をか
ねる水冷板、10はその水冷ボックスである。FIG. 3 is an explanatory view of an aluminum refining device for advancing solidification from the bottom of the container. 1 is a rotating magnetic field generator, 2 is a crucible (cylindrical container), 3 is molten aluminum, 4 is a solidified aluminum layer, Reference numeral 9 is a water cooling plate which also serves as the bottom of the crucible 2, and 10 is its water cooling box.
【００３１】これらの調査結果を図４（ａ）及び（ｂ）
にまとめて示す。図４の（ａ）は比較例、（ｂ）は適合
例のそれぞれ鋳塊縦断面における不純物成分Siの等濃度
曲線を示すグラフである。The results of these investigations are shown in FIGS. 4 (a) and 4 (b).
Are shown together. 4A is a graph showing the isoconcentration curve of the impurity component Si in the ingot vertical section of the comparative example, and FIG.
【００３２】図４（ａ）から明らかなように、比較例の
鋳塊は、純化領域と不純物濃化領域とが存在し、アルミ
ニウム溶湯の回転流中心に相当する部分には、純化され
ないままのアルミニウムないしは不純物が濃化したアル
ミニウムが凝固していて、鋳塊の上方、すなわち凝固が
進行するに従って不純物成分がより濃化したアルミニウ
ムの凝固層が存在している。これに対し、適合例の鋳塊
は図４（ｂ）から明らかなように鋳塊全体が高純化され
たアルミニウムであることを示している。As is clear from FIG. 4 (a), the ingot of the comparative example has a purified region and an impurity concentrated region, and the portion corresponding to the center of rotation of the molten aluminum remains unpurified. Aluminum or aluminum in which impurities are concentrated is solidified, and there is a solidified layer of aluminum in which impurity components are more concentrated above the ingot, that is, as the solidification progresses. On the other hand, the ingot of the conforming example shows that the whole ingot is highly purified aluminum as is clear from FIG. 4 (b).
【００３３】さらに、適合例の鋳塊を再溶解することに
よって、不純物成分Siの含有量を、アルミニウム地金の
0.07wt％から0.02wt％まで低減させることができたが、
比較例の鋳塊では、純化領域と不純物濃化領域が存在す
るため、上記のように不純物成分を低減させるために
は、不純物濃化領域を切削除去する必要があった。Further, by remelting the ingot of the conforming example, the content of the impurity component Si was changed to that of the aluminum ingot.
We were able to reduce from 0.07wt% to 0.02wt%,
In the ingot of the comparative example, there are a purified region and an impurity-concentrated region, so that the impurity-concentrated region needs to be cut and removed in order to reduce the impurity component as described above.
【００３４】[0034]
【発明の効果】この発明は、回分系の円筒容器内に供給
した純化対象のアルミニウム溶湯を、回転磁界により水
平回転流動させながら、円筒容器の側壁から冷却し、そ
の軸心に向けて凝固を進行させるものであり、この発明
によれば、純化を阻害する樹枝状晶を生成させることな
く、高純度アルミニウムが歩留りよく得られるようにな
り、さらに、溶湯段階で不純物濃化溶湯を排出するよう
にするため、不純物濃化領域のない鋳塊を得ることがで
きる。According to the present invention, the aluminum melt to be purified, which has been supplied into the batch-type cylindrical container, is cooled from the side wall of the cylindrical container while being horizontally rotated by the rotating magnetic field, and solidified toward the axis. According to the present invention, high-purity aluminum can be obtained with good yield without producing dendrites that hinder purification, and further, the impurity-concentrated molten metal is discharged in the molten metal stage. Therefore, it is possible to obtain an ingot without an impurity concentrated region.
【図１】この発明に適合する精製方法を実施するアルミ
ニウム精製装置例とその実施態様を示す説明図である。FIG. 1 is an explanatory diagram showing an example of an aluminum refining apparatus for carrying out a refining method according to the present invention and an embodiment thereof.
【図２】この発明に適合する精製方法を実施するアルミ
ニウム精製装置例とその実施態様を示す説明図である。FIG. 2 is an explanatory view showing an example of an aluminum refining apparatus for carrying out a refining method compatible with the present invention and its embodiment.
【図３】容器底部から凝固を進行させるアルミニウム精
製装置の説明図である。FIG. 3 is an explanatory diagram of an aluminum refining device that progresses solidification from the bottom of the container.
【図４】（ａ）は比較例の鋳塊縦断面における不純物成
分Siの等濃度曲線を示すグラフである。（ｂ）はこの発
明の適合例の鋳塊縦断面における不純物成分Siの等濃度
曲線を示すグラフである。FIG. 4A is a graph showing an isoconcentration curve of impurity component Si in a vertical cross section of the ingot of the comparative example. (B) is a graph which shows the isoconcentration curve of impurity ingredient Si in the vertical section of the ingot of the conformity example of this invention.
１ 回転磁界発生装置 ２ るつぼ ３ アルミニウム溶湯 ４ アルミニウム凝固層 ５ 水冷板 ６ 水冷ボックス ７ 排出孔 ８ ストッパー ９ 水冷板 10 水冷ボックス 1 Rotating magnetic field generator 2 Crucible 3 Molten aluminum 4 Aluminum solidified layer 5 Water cooling plate 6 Water cooling box 7 Discharge hole 8 Stopper 9 Water cooling plate 10 Water cooling box
───────────────────────────────────────────────────── フロントページの続き (72)発明者 反町 健一 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究本部内 (72)発明者 藤井 徹也 千葉県千葉市中央区川崎町１番地 川崎製 鉄株式会社技術研究本部内 (72)発明者 大滝 光弘 東京都千代田区丸の内２丁目６番１号 古 河電気工業株式会社内 (72)発明者 尾原 弘一 東京都千代田区丸の内２丁目６番１号 古 河電気工業株式会社内 (72)発明者 杉崎 健 東京都千代田区丸の内２丁目６番１号 古 河電気工業株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Sorimachi, No. 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture, Technical Research Division, Kawasaki Steel Co., Ltd. (72) Tetsuya Fujii, No. 1 Kawasaki-cho, Chuo-ku, Chiba-shi (72) Inventor Mitsuhiro Otaki 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Koichi Ohara 2--6, Marunouchi, Chiyoda-ku, Tokyo No. 1 Furukawa Electric Co., Ltd. (72) Inventor Ken Sugisaki 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Within Furukawa Electric Co., Ltd.
Claims (2)
ウム溶湯を、回転磁界により水平回転流動させながら、
円筒容器の側壁から冷却し、その軸心に向けて凝固を進
行させることを特徴とするアルミニウムの精製方法。1. An aluminum molten metal supplied into a batch type cylindrical container is horizontally rotated by a rotating magnetic field,
A method for purifying aluminum, which comprises cooling from a side wall of a cylindrical container and advancing solidification toward the axis thereof.
過程の中途段階で水平回転流動を停止し、円筒容器底部
に設けた排出孔から不純物溶質成分が濃化した残部溶湯
を円筒容器外に排出することを特徴とするアルミニウム
の精製方法。2. The method according to claim 1, wherein the horizontal rotary flow is stopped at an intermediate stage of the solidification process of aluminum, and the residual molten metal in which the impurity solute component is concentrated is discharged to the outside of the cylindrical container through a discharge hole provided at the bottom of the cylindrical container. A method for purifying aluminum, which is characterized in that:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5234897A JPH0790407A (en) | 1993-09-21 | 1993-09-21 | Method for refining aluminum |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5234897A JPH0790407A (en) | 1993-09-21 | 1993-09-21 | Method for refining aluminum |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0790407A true JPH0790407A (en) | 1995-04-04 |
Family
ID=16978020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5234897A Pending JPH0790407A (en) | 1993-09-21 | 1993-09-21 | Method for refining aluminum |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0790407A (en) |
-
1993
- 1993-09-21 JP JP5234897A patent/JPH0790407A/en active Pending
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