US3477844A - Aluminum reduction of beryllium halide - Google Patents

Description

Nov. 11, 1969 J. H. JACKSON ET l- 4 ALUMINUM REDUCTION OF BERYLLIUM HALIDE Filed June 15, 1966 FIG.

INVENTORS. JOHN HARRY JACKSON WALTHER SCHMIDT FIG. 2

ATTORN E Y5.

United States Patent 3,477,844 ALUMINUM REDUCTION OF BERYLLIUM HALIDE John Harry Jackson, Richmond, and Walther Schmidt, Henrico County, Va., assignors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed June 15, 1966, Ser. No. 557,647 Int. Cl. C22c 21/00, 1/00 US. Cl. 75-63 11 Claims This invention relates to the production of beryllium and beryllium alloys of high purity and improved properties. More particularly, the invention concerns an improved method of preparing beryllium-aluminum alloys from beryllium halides by reduction with aluminum and for the separation and recovery of such alloys.

Although most low density metals posses a low modulus of elasticity, beryllium is unique in having a very low density 1.8 g./ cc.) and a very high modulus of elasticity, of the order of 43,000,000 p.s.i. This makes beryllium and its alloys desirable as a material of construction in applications where resistance to buckling is of importance. However, the impurities which are present is commercially available beryllium adversely affect its toughness and ductility. Aluminum is commonly alloyed with beryllium in an effort to offset this loss is ductility, an example of a commercial alloy of this type being Lockalloy, containing 62% Be and 38% Al, by weight. But even in the case of alloys containing beryllium in amounts of as little as 1% or as great as, say 80%, it is most desirable to provide the purest beryllium possible in the alloy combination.

In accordance with the method of the present invention, a beryllium halide is employed as the starting material for the separation and alloying of beryllium. The beryllium halide is preferably beryllium choride BeCl but the other halides, such as the fluoride BeF the bromide BeBr and the iodide BeI are also within contemplation of the invention.

Many methods have been proposed for obtaining beryllium halides from beryllium ores. Thus, for example, it is known to produce BeCl by chlorinating beryllium oxide or beryl ore in presence of carbon, or by heating the ore in an electric furnace with carbon to form beryllium carbide, followed by hydrochlorination with HCl gas. The common characteristic of these ore extraction methods is that various impurities are introduced, including one or more of the elements B, Cd, Ca, C, Cr, Co, Cu, Fe, Pb, Li, Mg, Mn, Mo, Na, N, Si, Ag, Zn and Ni. The present invention provides a novel method whereby these impurities may be successfully minimized.

Beryllium chloride may also be made by reacting beryllium metal, i.e. impure metal or scrap, with C1 or HCl vapor. By this method impurities which do not vaporize in the C1 or HCl stream at selected conditions of temperature, pressure and/ or concentration, may be eliminated. The process of the invention is applicable to beryllium halides whatever the source, but beryllium chloride prepared from commercial metallic Be is employed for purposes of illustration.

It has been proposed to reduce beryllium chloride by the removal of the chlorine by means of a metal, such as aluminum, which forms a low boiling point chloride, in accordance with the equation: 3BeCl +2Al 2AlCl -|-3Be. An article by Fischer et al., in Metall und Erz, Zts., fuer Metallhuttenwesen und Ersbergbau, vol. XXX, 1933, pp. 390-391, discloses performing this reduction by heating aluminum powder with solid beryllium chloride, at temperatures from 260 to 350 C., in a hydrogen atmosphere. This has the disadvantage of requiring operation in a reducing atmosphere, including recovery of the beryllium formed, in order to avoid conversion of nearly all to the oxide.

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In accordance with a first aspect of the invention, it has been found that beryllium halide can be reduced to beryllium metal by introducing the halide in vapor form into a bath of aluminum in the liquid state.

The beryllium thus liberated forms an alloy with the aluminum to an extent consonant with the aluminumberyllium phase diagram. It is known that a Be-Al eutectic containing 1.4% Be exists at 644 C. Thus, alloys containing in excess of 1.4% may be designated hypereutectic alloys, and it is the production of these alloys which is one of the primary objects of the invention.

The temperature of operation of the reduction system is determined primarily by the liquidus temperature of the desired Be-Al alloy. In general, the hypereutectic alloys are produced by reacting BeCl vapor with molten aluminum at a temperature above about 660 C. A temperature as high as 1200 C. would be needed to produce an 84.5% Be alloy. The temperature in this mode of operation is maintained high enough to keep the reduced Be in solution, and is then lowered to allow the hypereutectic Be content to crystallize out, followed by physical separation of the mixture of Be crystals and residual alloy. The beryllium is crystallized out at a temperature above, but close to the eutectic temperature, meaning the range of 650- 800 C. The lower the temperature is chosen in practical work, the higher is the yield of solid crystals. The preferred temperature is below 700 C., e.g., 660-680 C.

In an alternate procedure, the hypereutectic Be-Al alloy is produced by reacting molten aluminum with Be halide vapor at a temperature substantially above 660 C., so as to supersaturate the aluminum with beryllium above the concentration of the solution at the reaction temperature, and continuing to liberate Be until the Be produced in an amount exceeding its solubility in the Al forms a top layer, enriched in Be crystals, and then separating and purifying said top layer. It is also possible to operate somewhat below the hypereutectic liquidus temperature, depending upon the viscosity of the liquid-solid mixture that is formed and its resistance to bubbles of Be halide vapor. In this way, hypereutectic alloys containing from 1.5 to 30% Be can be obtained.

The reduction may be carried out either in batch or continuous manner. In a batch operation the reaction of the beryllium halide can continue until the solids increase to the point where operation is impeded. In a continuous process the reaction proceeds with the beryllium crystals forming and floating to the top of the molten Al bath, whence they can be removed continuously. Make-up aluminum is added to the bath in amounts as required.

The reaction of beryllium halide vapor and molten aluminum bath may be performed, for example, in the apparatus illustrated in FIG. 1 of the accompanying drawings. The apparatus comprises at its upper end a chamber 1 which is filled with granules of metallic beryllium 2 through a feed inlet 3 located at the upper end of the chamber. Chamber 1 is also provided with inlet 4 for the introduction of a halide bearing gas, such as, for example HCl. At the bottom, chamber 1 is provided with conduit 5 which is protected by cover 6 which prevents beryllium metal from entering the conduit. Conduit 5 serves to transfer BeCl vapor generated in chamber 1, to a second chamber 7 positioned beneath chamber 1, and which serves as a zone for maintaining a bath of molten aluminum metal 8 therein. Conduit 5 is fitted with a sparging plug 9 in order to introduce into the aluminum bath BeCl bubbles of minimum size. Melting chamber 7 is provided with heating means shown generally at 10. The space between the Be halide formation chamber 1 and the aluminum melting chamber 7 is provided with inlet 11 for feeding metallic aluminum to chamber 7, and with exit 12 leading to condensing system 13 for collecting condensed vapors of aluminum and beryllium halides formed and unconverted in chamber 7. Also provided are auxiliary heating means 14 and 15 to prevent condensation.

In the operation of the apparatus of FIG. 1, beryllium and aluminum are fed to the halogenation chamber 1 and the aluminum melting chamber 7, respectively, and heated under cover of an inert gas until the Be becomes hot and the Al molten. Inert gas flow is stopped from the Be halogenation chamber and halide bearing gas, such as HCl gas, is introduced through inlet 4, passing through the heated bed of beryllium granules in chamber 1. Beryllium halide gas forms and flows through tube to bubble through the molten aluminum bath, small sized bubbles proyiding maximum surface area for the reaction. Gaseous reaction products arising from the bath are carried by the flow of inert gas to the exit port to the condenser system and subsequently deposit on the condenser surfaces.

The preparation of beryllium-aluminum alloy by reduction of beryllium halide vapor with molten aluminum is illustrated by the following examples, which are not, however, to be regarded as limiting:

Example 1 1650 grams of spherical granules of beryllium metal having an average diameter of about /s-inch were charged to the halogenation chamber 1 of the apparatus of FIG. 1 so as to completely fill the container. A quantity of 375 grams of aluminum was fed to the melting chamber 7. Both chambers were heated while maintaining a flow of inert gas to protect their contents. When the temperature of the aluminum bath reached llOO C. and that of the beryllium reached 732 C., the flow of inert gas to the halogenation chamber was replaced by HCl gas flowing at a rate of 1365 cc./min. Temperature of aluminum and beryllium contents and flow of HCl gas were maintained at the aforementioned levels for 17 hours. At the end of this period, the heat was discontinued and the aluminum cooled to room temperature. Analysis of the ingot indicated a beryllium content of 3.12 percent by weight.

In accordance with an alternative procedure, the reduction of the beryllium halide to beryllium can be carried out by continuing the reaction with molten aluminum until the aluminum becomes supersaturated with beryllium, or with hypereutectic Be-Al alloy, whereupon Be produced in a quantity exceeding its solubility in the aluminum forms a top layer, enriched in Be crystals, which top layer is removed and then purified.

In accordance with still another alternative procedure, the reduction of the beryllium halide, not in vapor form, but in the form of a melt with an alkali or alkaline earth metal halide, such as sodium chloride, or with a molten mixture of sodium and aluminum chlorides, or of ammonium and aluminum chlorides, may be performed with finely divided aluminum maintained in suspension in the bath. Or else liquid aluminum can be maintained in contact with a salt melt containing the beryllium halide, while applying a temperature at which the Be halide and the aluminum will react, preferably above 660 C. in order to facilitate formation of a hypereutectic Be-Al alloy, for example, about 800 C. Salt melts, which may be employed as carriers for the beryllium halide can be classified as supernatant, which are lighter than aluminum and will fioat on top of the aluminum and those which are heavier than aluminum, so that the aluminum will dwell upon them.

Supernatant salt systems which are applicable are described in the book by E. M. Levin et 211., Phase Diagrams for Ceramists, published by The American Ceramic Society, Inc. 1964, including binary systems of LiCl- BeCl NaCl-BeCl KF-BeF MgF -BeF CaF -BeF KF-NaF-BeF Since this invention contemplates temperatures of reaction up to approximately llOO C., supernatant salt melts must consider the higher volatility of BeCl as compared with MeF (boiling points of BeCI 4 487 C. and of BeF z 1159 C.). The fluoride is therefore preferred for a supernatant salt melt.

Example 2 By way of example, a supernatant salt melt is advantageously used containing approximately KF and 20% BeF by weight percent, melting at 720 C. This floats on top of the aluminum. The combined salt and aluminum melts are heated to approximately 1050 C. During reaction, the quantity of BeF is regulated, preferably by periodic additions, until the aluminum has absorbed enought Be to result in a content of approximately 810% Be. The AlF resulting from the reaction, is absorbed by the supernatant bath, which gradually changes to the ternary system KF-BeF -AlF The obtained Al- Be alloy is removed from the reaction vessel at a temperature around 1050 C., at which all the absorbed Be is still in solution. It is then subjected to partial crystallization and is separated by centrifugation.

It is evident from this example that it is advisable not to increase the concentration of Be in the Al beyond the soluble content at the reaction temperature, if a supernatant salt melt is used.

In contrast, by employing a salt melt heavier than aluminum, the Be content can be allowed to go higher than the solubility limit and Be crystals may be permitted to crystallize and accumulate at the top level of the aluminum without being contaminated by salt. In this case it is preferred to use BeCl and allow the resulting AlCl to vaporize 01f. Of course BeF can be used too because the resulting AlF is absorbed by the heavy salt melt. However, the change in specific gravity would require closer control, if the fluoride is used.

The binary system BaCl -BeCl may be used, e.g., at 950 C. -95 mol percent BaCl and 10-5 mol percent BeCl The latter can be kept within the salt melt without excessive evaporation more conveniently if a ternary mixture, e.g., 10% KCl, 87% BaCl 3% BeCl (in weight percent) is used. In any case, the BeCl content is replenished, preferably by bubbling BeCl vapor into the salt mixture.

Example 3 By way of example, a salt melt of approximately 11% KCl, 11% NaCl, 75% BaCl 3% BeCl (in weight percent) is prepared, melting at approximately 600 C. It is heated to approximately 700 C. and molten aluminum is placed atop of it. The temperature is raised to ap proximately 1000 C. and BeCl vapor is introduced into the salt bath, maintaining its BeCl concentration while the reaction proceeds. This is continued until the aluminum is saturated, with approximately 10% Be dissolved, and about an equal amount of Be crystals which float on and underneath the top level. The level is protected from oxidation by argon. The top level is skimmed off from time to time and cooled to approximately 670 C., and then separated by centrifugation. After the aluminum, entrained by the skimmings is replenished, the reaction is continued and the operation repeated.

As is evident from the art of molten salt systems, the salt melts, carrying the Be halide may be selected from the group consisting of halides of alkali and alkaline earth metals including magnesium. All mixtures of such halides have melting points below the preferred temperature of reaction around 1000 C. and in all odd combinations of such halides exists a sufiicient solubility for Be halides. Bebromide and -iodide behave much the same as Be chloride. Though they can technically be used, they are more expensive and therefore less advisable.

After the aluminum has become saturated or supersaturated with beryllium, it is tapped and cooled in a separate vessel to approximately 660 C., thus crystallizing out Be, and the separated near-eutectic liquid is returned to the reaction vessel for recycling to contact the BeCl -containing salt melt. The Be thus formed may then be separated by suitable means.

In accordance with another aspect of the invention, it has been found that, in employing any of the foregoing reduction methods, the concentration of beryllium in the aluminum can be greatly improved, being increased to the extent of 15% by weight and more, by having present in the aluminum from about 5% to about 35% by weight of either an alkali metal or an alkaline earth metal, the latter including magnesium. These additives to the aluminum appear to exert a potentiating effect, inasmuch as they are individually more efiicient reductants for beryllium halides than aluminum itself. Thus, there may be employed in this manner Mg, Na, K or Ca, of which Mg is preferred. Small residual amounts of these auxiliary reductants can be removed with the liquid phase in subsequent separation steps, such as, for example, in centrifuging in accordance with another aspect of the invention. The temperature of the reduction step should be maintained above the melting point of the resulting halide salts, such as MgCl NaCl or KCl. Where a mixture of the auxiliary reductant metals is used, the reduction temperature should be above the melting point of the resultant salt melt of the mixed halides. The concentration of the auxiliary reductant should advisedly be such that at the temperature of reduction all Be formed will stay dissolved in the aluminum so that the salt formed cannot contaminate but must float to the top of the bath from which it is removed. The Be-Al alloy is then transferred while at or above the temperature of complete dissolution to the next step of crystallization and separation by centrifuging or filtration.

Thus, in accordance with the invention, it is possible to obtain a concentration of Be in aluminum of about 15% by weight, by employing for the reduction of the Be halide a molten mixture of Mg and Al in which the ratio of Mg to Al is approximately 1:2 by weight. The temperature of the bath should be about 1100 C. in order that all Be liberated will be completely dissolved. Under this condition, the MgCl formed rises to the surface of the bath and does not contaminate the underlying liquid alloy. The Be-Al alloy and the MgCl are removed via separate outlets.

The boiling point of Mg is 1117 C., and even at the dilution of 1:2 in Al, there will be substantial Mg vapor pressure. This effect may be avoided by feeding the magnesium gradually into the aluminum bath as the reaction progresses. With a lower Mg concentration, for example 5% to present at any given time, the Mg vapor pressure is sufficiently suppressed to permit operation at 1100" C. Residual magnesium can be effectively removed from the alloy in subsequent centrifugal purification. It is also possible to bubble a limited amount of chlorine gas through the melt, which will preferentially attack magnesium. Such treatment may be employed prior to crystallization of the beryllium and thus prior to a separation of solid and liquid phases by mechanical means, like centrifugation.

In FIG. 2 of the accompanying drawings, there is shown a schematic arrangement of an apparatus suitable for carrying out reduction of a beryllium halide with a MgtAl mixture. The operation of this apparatus is illustrated, as is this aspect of the invention, by the following example:

Example 4 Reaction vessel 101 is filled with a mixture of Mg and Al, in which the Mg concentration is about 5% by Weight to a level 102. The temperature in vessel 101 is maintained at 1100 C. Vapor of BeCl is bubbled through the molten metal bath through sparger 103. As Mg is consumed, more Mg is metered into vessel 101 from source 104, which is a container filled with liquid magnesuim. Thus, the concentration of Mg in vessel 101 is either intermittently or continuously replenished to maintain the concentration at about 5% until the supply of Mg and BeCl is consumed. A liquid pool of MgCl which will also contain some excess BeCl and possibly small amounts of AlCl due to side reactions, is permitted to rise to level 105. By tapping outlet 108, the level of liquid alloy is lowered to level 109. After a portion of the alloy has been tapped, more aluminum is introduced into vessel 101 from supply vessel 110, raising the level of the liquid metal bath once more to position 102. Then the upper tap-hole 106 is opened and a portion of liquid MgCl is released allowing the salt to drop to level 107. In semicontinuous operation, vessel 101 is never completely emptied in order to avoid contamination. Vessel 101 may be heated inductively or by immersed electrodes using the salt as a resistor. By subsequent concentration and purification by centrifuging in accordance with the invention, the magnesium content of the Be-Al alloy may be reduced to 0.02% to 0.01%.

In accordance with a further aspect of the invention, it has been found that the concentration of Be in molten hypereutectic Be-Al alloys, containing between about 1.5% and 30% Be, may be greatly increased and the Be obtained in a high degree of purity by crystallizing out beryllium at a temperature above, but close to the eutectic temperature (644 C.) and then mechanically separating at that temperature into two fractions. One fraction contains substantially more Be in the form of solid crystals in admixture with a portion of the aluminum matrix than the other separated fraction. The latter comprises a substantially larger portion of the A1 matrix and is virtually free from Be crystals.

Thus, the foregoing method is based upon the principle of reacting aluminum at a temperature substantially above 660 C. with a beryllium halide to form a hypereutectic Be-Al alloy, maintaining the temperature high enough to keep the reduced Be in the form of hypereutectic alloy in solution in the aluminum, and then lowering the temperature to allow the hypereutectic alloy to crystallize out, and then separating the crystals. The aluminum bath may contain for this purpose any of the auxiliary reductants previously mentioned.

The foregoing method has the advantage of causing the impurities present in the Be-Al alloy, such as B, Cd, Ca, C, Cr, C0, Cu, Fe, Pb, Li, Mg, Mg Si, Mn, Mo, Na, N, Si, Ag, Zn and Ni to be partially removed from the beryllium-rich fraction and to be concentrated in the second fraction by virtue of their solubility in the aluminum matrix.

It the auxiliary reductant used is Mg, it may be desirable to leave some Mg or Mg Si in the Al matrix, since these constituents may impart desirable properities to the resulting Be-Al alloy.

The aluminum content of a supernatant layer of Be or Be-Al hypereutectic crystals is a function of crystal size, which in turn is controlled by regulation of time and temperature of formation. Thus, rapid cooling to just above euctectic temperature and fast settling will produce very fine crystals, which may not float upward except in prolonged time. On the other hand, slow cooling will grow crystals large enough to float readily on the surface of the liquid eutectic. Intermediate cooling rates will produce Be crystals which will form a cream-like layer, having more Al trapped between them. Hence control of the rate of crystallization may be employed to obtain mixture of Be and A1 of different proportions.

For example, if Al and 10% Be by Weight are heated to 1050" C., and rapid heat withdrawal is effected by cooling within 2 minutes to 660 C. by pouring the mixture on a lead bismuth bath at less than 300 C. temperature, there results a cream-like layer of fine Be crystals in a eutectic liquid, which is allowed to float by its own buoyancy for no more than 10 minutes. After this it may be removed either by skimming or preferential withdrawal of the eutectic through a filter, e.g. a layer of powdered aluminum or beryllium or Al-Be alloy e.g.

crystals left in the filter from a previous operation, or alternatively, by centrifuging. a

If the foregoing Be-Al mixture is heated to 1050 C., and cooled slowly over a 10 hour period to 660 C. by even withdrawal of heat, large crystals form and float to the surface. Slow rate of crystallization has also the advantage that impurities, dissolved in the aluminum matrix have less tendency to attach themselves to the growing Be crystals, but remain substantially concentrated within the liquid phase.

Alternatively, the starting material for eutectic separation may be a partially molten Be-Al alloy, produced by reduction is previously described, by supersaturating the molten aluminum with Be at the reaction temperature, allowing a top layer enriched in Be crystals to form, and separating and purifying the Be crystals by centrifuging.

In accordance with another aspect of the invention, it was found that simultaneous concentration and purification of beryllium is achieved by centrifuging a partially molten alloy of Be and Al. Further concentration and purification can be attained by additional centrifuging steps. It is possible to reslurry the Be crystals with more aluminum of high purity, in order to offer more aluminum solvent for the impurities and increase the effect of purification in a subsequent centrifugal separation. In carrying out this centrifuging, a force is employed which is commensurate with the amount of aluminum matrix desired to be retained with the Be crystals. An alloy of Be and Al is heated to a temperature at least equal to the liquidus temperature for the alloy in question to insure homogenous solution of components including impurities. The heated material is then poured into a refractory cup connected to a centrifuge. The material contained in the cup is allowed to cool to a temperature lower than the liquidus temperature so that a portion of Be begins to solidify. The refractory cup is then spun at a speed which will actually depend upon cup diameter, since it is peripheral speed which is determinative. Upon spinning, heavier liquid having a higher content of aluminum is thrown from the refractory cup, while a mixture of residual liquid and solid material remains confined therein. The residual liquid, which is rich in aluminum. is retained within the soonzv network of Be crystals. The relative amounts of liquid and solids can be controlled by varying the centrifugal force.

The folowing examples illustrate the practice of this aspect of the invention:

Example A beryllium oxide crucible was charged with a total of 400 grams of Be and Al in proportions such as to yeld an alloy containing by weight of beryllium. The

' analysis of the charged materials is given below:

Beryllium Aluminum Element, percent (by weight):

Sufficient heat was applied to the crucible to melt the contents while surrounding the crucible With an inert helium atmosphere. Following melting, superheat was applied to raise the temperature of the metal to 1370 C. so as to assure homogeneity. An ingot of the above alloy was cooled to room temperature. The ingot weighing 375 grams was subsequently re-melted under a helium atmosphere and heated to 1200 C. A total of 340 grams of this melt was poured into a refractory cup having inner Walls of an inverted truncated conical shape and being aflixed at its base to the shaft of a spinning device. The

. dimensions of the cup were so that the extreme edge of the mass was approximately 2 inches from the axis of rotation. The metal confined in the cup cooled to a temperature within the range of 760-790" C. and was then spun for 1 minute at a speed of 400 rpm. During spinning, 230 grams of material was retained in the refractory cup whereas grams were ejected therefrom. The ejected material contained less than 1 percent of beryllium and the retained material contained 17 percent of beryllium. The microstructure of the ejected material showed no massive primary crystals of beryllium whereas the same was clearly evident in the retained material.

Example 6 Material retained in the refractory cup following the spinning of Example 5 was melted and cast into 225 gm. ingot as described for the starting materials of Example 5. A total of 200 grams of material re-melted to 1200 C. as in Example was poured in the refractory cup described therein. Spinning of the metal was done at a speed of 400 rpm. and at a metal temperature of 760790 C. During spinning, grams of material was retained in the cup and 60 grams were ejected therefrom. The chemical analysis of the retained material is given below.

Percent by weight Starting material l7 Analyses of concentrate:

Be 27 Fe 0.01 Si 0.03 Cr 0.001 Mn tr Mg 0.01 Pb tr Cu 0.02 Ti 0.005 Ni tr It can be seen that the concentration of beryllium in the retained material was increased to 27 percent of beryllium. A11 alloy of similar beryllium concentration produced from the starting materials described in Example 5 would contain 0.025 percent of iron and 0.0026 percent of chromium. It can be seen that the beryllium-aluminum alloy containing 27 weight percent beryllium produced by the method of this process contains about 60 percent less of the elements iron and chromium than would the corresponding virgin alloy.

The examples hereinabove described show that centrifuging can be used as a means of concentrating and purifying beryllium from an aluminium beryllium alloy.

What is claimed is:

1. Method for the production of beryllium-aluminum alloys which comprises the steps of reacting beryllium halide with molten aluminum at a temperature above about 660 C. and sufliciently high to maintain the liberated beryllium in solution in the molten aluminum, to form a hypereutectic alloy of beryllium and aluminum, reducing the temperature to partially crystallize said alloy, and separating substantially the solid phase.

2. Method for the production of beryllium and beryllium-aluminum alloys which comprises the steps of reacting beryllium halide which molten aluminum at a. temperature above about 660 C. to form a hypereutectic alloy of beryllium and aluminum in solution in the molten aluminum, continuing the reaction until the aluminum is supersaturated with beryllium at the reaction ternperature, ryllium in excess of its solubility in the aluminum forms a top layer on the surface of the aluminum enriched in beryllium crystals, and separating beryllium crystals from said top layer.

3. The method of claim 2 in which the beryllium halide is beryllium chloride.

4. The method of claim 2 in which the beryllium crystals are separated by centrifuging.

5. Method for the production of beryllium-aluminum alloys which comprises the steps of forming a molten mixture of a beryllium halide and at least one metal halide selected from the group consisting of halides of alkali and alkaline earth metals including magnesium, reacting said mixture with molten aluminum at a temperature above 660 C. and sufliciently high to maintain the liberated beryllium in solution in the molten aluminum, to form a hypereutectic alloy of beryllium and aluminum, reducing the temperature to partially crystallize said alloy, and separating substantially the solid phase.

6. Method for the production of beryllium-aluminum alloys which comprises the steps of reacting beryllium halide with molten aluminum having dissolved therein from about 5% to about 35% by weight of a member selected from the group consisting of an alkali metal, an alkaline earth metal, and magnesium, at a temperature above about 660 C. and sufficiently high to maintain the liberated beryllium in solution in the molten aluminum, to form a hypereutectic alloy of beryllium and aluminum, reducing the temperature to partially crystallize said alloy, and separating substantially the solid phase.

7. The method of claim 6 in which the aluminum contains magnesium in an amount sufiicient to act as a major reductant for the beryllium halide.

8. The method of claim 6 in which magnesium and any magnesium silicide formed remain substantially in the aluminum.

9. Method for concentrating beryllium metal content in hypereutectic beryllium-aluminum alloys which comprises the steps of melting said hypereutectic alloy, crystallizing out beryllium at a temperature above, but close to the eutectic temperature, and mechanically separating the mixture into two fractions, one containing substantially more beryllium in the form of solid crystals in admixture with a portion of the aluminum matrix, and the other comprising a substantially larger portion of the aluminum matrix and being virtually free from beryllium crystals.

10. The method of claim 9 in which the fractions are obtained by centrifuging.

11. The method of claim 9 in which the beryllium is crystallized at a rate slow enough to allow impurities present in the alloy to be substantially removed from the beryllium fraction, concentrating said impurities in the aluminum matrix fraction by reason of their solubility therein.

References Cited UNITED STATES PATENTS 1,648,954 11/1927 Marden 845 X 2,193,363 3/ 1940 Adamoli 7584.4 2,193,364 3/1940 Adamoli 7584.4 2,452,665 11/1948 Kroll et al. 7563 2,471,899 5/1949 Regner 7563 3,374,089 3/ 1968 Robinson et al. 7563 X L. DEWAYNE RUTLEDGE, Primary Examiner H. W. TARRING II, Assistant Examiner US. Cl. X.R.

Claims (3)

1. METHOD FOR THE PRODUCTION OF BERYLLIUM-ALUMINUM ALLOYS WHICH COMPRISES THE STEPS OF REACTING BERYLLIUM HALIDE WITH MOLTEN ALUMINUM AT A TEMPERATURE ABOVE ABOUT 660*C. AND SUFFICIENTLY HIGH TO MAINTAIN THE LIBERATED BERYLLIUM IN SOLUTION IN THE MOLTEN ALUMINUM, TO FORM A HYPEREUTECTIC ALLOY OF BERYLLIUM AND ALUMINUM, REDUCING THE TEMPERATURE TO PARTIALLY CRYSTALLIZE SAID ALLOY, AND SEPARATING SUBSTANTIALLY THE SOLID PHASE.

2. METHOD FOR THE PRODUCTION OF BERYLLIUM AND BERYLLIUM-ALUMINUM ALLOYS WHICH COMPRISES THE STEPS OF REACTING BERYLLIUM HALIDE WHICH MOLTEN ALUMINUM AT A TEMPERATURE ABOVE ABOUT 660*C. TO FORM A HYPEREUTECTIC ALLOY OF BERYLLIUM AND ALUMINUM IN SOLUTION IN THE MOLTEN ALUMINUM, CONTINUING THE REACTION UNTIL THE ALUMINUM IS SUPERSATURATED WITH BERYLLIUM AT THE REACTION TEMPERATURE, AND BERYLLIUM IN EXCESS OF ITS SOLUBILITY IN THE ALUMINUM FORMS A TOP LAYER ON THE SURFACE OF THE ALUMINUM ENRICHED IN BERYLLIUM CRYSTALS, AND SEPARATING BERYLLIUM CRYSTALS FROM SAID TOP LAYER.

9. METHOD FOR CONCENTRATING BERYLLIUM METAL CONTENT IN HYPEREUTECTIC BERYLLIUM-ALUMINUM ALOOYS WHICH COMPRISES THE STEPS OF MELTING SAID HYPEREUTECTIC ALLOY, CRYSTALLIZING OUT BERYLLIUM AT A TEMPERATURE ABOVE, BUT CLOSE TO THE EUTECTIC TEMPERATURE, AND MECHANICALLY SEPARATING THE MIXTURE INTO TWO FRACTIONS, ONE CONTAINING SUBSTANTIALLY MORE BERYLLIUM IN THE FORM OF SOLID CRYSTALS IN ADMIXTURE WITH A PORTION OF THE ALUMINUM MATRIX, AND THE OTHER COMPRISING A SUBSTANTIALLY LARGER PORTION OF THE ALUMINUM MATRIX AND BEING VIRTUALLY FREE FROM BERYLLIUM CRYSTALS.

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