LU82561A1 - PROCESS AND PLANT FOR THE PRODUCTION OF REACTIVE METALS, ALLOYED OR NON-ALLOYED, BY REDUCTION OF THEIR HALIDES - Google Patents

Description

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The present invention relates to a process for the production, preferably continuously, of reactive metals, alloyed or not, by reaction of their halides, in particular chlorides, with a reducing agent, at a temperature above the temperature of fusion of the metal to be produced.

By reactive metals, it should be understood! dre, for the present invention, titanium, zirconium, hafnium, tantalum, niobium, molybdenum, tungsten, vanadium, aluminum, silicon, cobalt, nickel, magnesium, thorium, uranium, [beryllium and chromium.

! | The known methods for preparing the aforementioned metals generally have the disadvantage, i: either of being discontinuous, or of requiring a step of remelting the metal, or of being costly in energy, or I of having very metallurgical yields weak.

One of the essential aims of the present invention consists in proposing a method which makes it possible to remedy these drawbacks.

It is more particularly a process which allows the following results to be obtained: - Metals are formed directly and continuously in the liquid state, the heat necessary for the fusion of certain metals, or at least part of this is provided: by exothermic reactions, this mistletoe therefore makes it possible to save a large part of energy; - The metal is collected in a dense form, preferably in a cooled copper ingot mold.

! To this end, the process according to the invention consists in solidifying the metal produced while maintaining i in the reaction zone, where the, i \ • - "takes place. 4 S 3 jjj reduction ,, a layer of this metal in the liquid state, the temperature being more than the boiling or sublimation temperature of the other reaction products, at the pressure where the reduction takes place, these others reaction products being evacuated, substantially continuously, in the gaseous state.

Advantageously, it consists in maintaining a layer of metal to be produced in the liquid state above the solidified metal, the latter being in the form of an ingot which is extracted substantially continuously, as the preparation takes place. of said metal.

According to a particular embodiment of the invention, the reagents are introduced into | i! The above reaction zone in the gaseous state.

According to a preferred embodiment, the reactants are introduced into the reaction zone according to a vortex current so as to allow the coalescence of the droplets of liquid metal formed by the reaction in this current and to subject them to a centrifugal force.

The invention also relates to an installation for the implementation of the above process.

This installation is characterized by the fact that it comprises a device for introducing, in the gaseous state, the reagents participating in the aforementioned reaction into the upper part of a cooled ingot mold, and a device for evacuation, in continuous, ë | gases from the reduction.

Finally, the invention also relates to the metal developed by the implementation of the method and / or by means of the installation as described above. /! / 1 ^ • 3! 4 4 t Other details and particularities of the invention will emerge from the description given below, by way of nonlimiting example, with reference to the appended drawings, of some particular embodiments of the process and of the following installation. the invention.

Figure 1 is a schematic view of a first embodiment of the method and the installation according to the invention.

1 Figure 2 is a diagrammatic representation of a second embodiment of this process and of this installation.

FIG. 3 is a schematic view in elevation and in section of a third embodiment of the method and of the installation according to the invention.

Figure 4 is a section along line IV-IV of Figure 3.

! In the different figures, the same | reference numbers designate similar elements | or identical.

! According to the method of the invention, ef- [; performs the reduction of a halide of a metal to be produced,! in particular chloride thereof, at a temperature above- | below the melting point of the metal being produced.

. More particularly, the temperature of | reaction is also maintained above the temperature! boiling or sublimation of all substances other than metal present in the reaction zone, at the pressure at which the reduction takes place.

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These substances therefore spontaneously leave the reaction zone in the gaseous state. / * ·! ^ / i

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The process according to the invention makes it possible, in particular, to considerably reduce the cost price of titanium, this mistletoe makes it accessible to numerous applications throughout the industry. This process also applies to the continuous production of zirconium, hafnium, tantalum, niobium, molybdenum, tungsten, aluminum, silicon, cobalt, nickel, magnesium, thorium, uranium, beryllium and chromium.

The invention relates, as already indicated above, in addition, an installation for the preparation,

Ien continuously, these reactive metals by the reduction of their halides, in particular for the implementation of the above process.

This installation constitutes a functional apparatus suitable for use on an industrial scale with very high productivity.

The appended figures make it possible to illustrate more concretely some particular embodiments. process and installation according to the invention for the production of reactive metals by reduction of their halides.

The embodiment shown diagrammatically! . only in Figure 1 includes a closed chamber 1! located above an ingot mold 2 cooled, in particular K by a circulation of water not shown, a device -i 3 for introducing reagents participating in the abovementioned reduction into the upper part 2 * of the ingot mold 2 | and a device 4 for the continuous evacuation of gases | from the reduction.

j The device 3 for introducing the reagents into the upper part 2 * of the ingot mold includes, for the halide of the metal to be produced, a first- / l / -Ί i 6 i first enclosure 5, located in an oven 6, connected by means of a positive displacement pump 7 to a second enclosure 8 provided in another oven 9.

This second enclosure communicates by an injection pipe 10 with this upper part 2 *.

An enclosure 11, also provided in an oven 12 and intended to contain a reducing metal, is j connected, by means of a positive displacement pump 13, I to another enclosure 14 of the oven 9. This enclosure 14 is, in its side, connected to the closed chamber 1. by a . injection pipe 15.

The embodiment of the installation shown in FIG. 1 is especially suitable for the reduction of metal halides occurring in the liquid state at pressure close to atmospheric pressure in a sufficiently wide temperature range.

In this case, the halide is kept in the liquid state in the enclosure 5 by possible heating by means of the oven 6 and is pumped, by means of the pump 7, into the enclosure 8 of the oven 9 where it is carried. to * boil.

This gaseous metal halide is then introduced into the upper part 2 ′ via the injection tube 10.

The reducing metal contained in the enclosure 11 is maintained at a temperature approximately 50 ° C. higher than its melting point thanks to the furnace 12.

This molten reducing metal is transferred; by means of the pump 13 inside the enclosure 14 where it is also brought to a boil.

The reducing metal in the gaseous state is then introduced, in a controlled manner, into the reaction zone of the closed chamber 1j via the / injection pipe 15. // ^ L / - 7 i! ?; *

The flow rate of the gaseous reducing metal is regulated by the flow rate of the liquid metal by means of the positive displacement pump 7 or of a power regulation in the vaporization step, not shown in FIG. 1.

In the reaction zone located in part 21 of the ingot mold 2, the temperature is higher than the melting temperature of the metal to be produced as well as the boiling or sublimation temperature of all the other substances participating in the reaction.

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The metal produced is collected in the ingot mold 2 which is formed from a cooled double-walled copper cylinder.

The upper layer 16 of the metal in contact

I with the reaction zone remains in the liquid state, while the metal 17 situated around and below this layer is solidified by said cooling and forms an il I ingot which is continuously extracted downwards, as indicated by the arrow 18, by means known per se, such as actuated rollers, not shown in the figure.

| All substances, other than metal, I lick. the reaction zone by the device 4 formed

Ipar by an evacuation chimney. These gases can optionally be directed to a condenser, not shown, to recover the unused reagents.

The closed chamber 1 being sealed, an atmosphere of inert gas, such as argon or helium, can, if necessary, be established in this chamber by a device 19, containing such a gas, which is connected, by *! ^ Via a tube 20, to this chamber 1.

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FIG. 2 represents a second embodiment of the installation according to the invention for the preparation of reactive metals by reduction of their halides.

This embodiment differs from that shown in FIG. 1 by the fact that only one enclosure 5 is provided in the device 3 for introducing the halide into the upper part 2 '| of the mold.

This embodiment is particularly suitable for the case where the halide is not liquid, such as for zirconium and hafnium.

Such halides are brought to the gaseous state by sublimation by heating them by means of the S furnace 6.

The gas flow from these halides to the

Reaction Izone is imposed by the power dissipated by this furnace.

Advantageously, in particular for metals which are not very refractory, such as titanium, aluminum, silicon, zirconium, thorium, vanadium, chromium, cobalt, magnesium, uranium and even nickel, the reaction of reduction is conducted under conditions | such as calories for maintaining the reaction zone! at the above temperature, that is to say higher! at the melting temperature of the metal to be produced and at f! boiling or sublimation temperature of all [i other substances participating in the reaction, be uni- | cally provided by the exothermic reaction between / I the halide of the metal to be produced and the reducing metal, i. · / ·· / such as an alkali or alkaline earth metal. / ./ he /·

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For moderately refractory metals, the metal to be produced can be separated by simultaneous reduction of the halide by such a reducing metal and by hydrogen. These include metals such as titanium, zirconium, thorium, uranium, hafnium, chromium, cobalt, vanadium and possibly, in some cases, nickel.

Finally, for very refractory metals, such as tantalum, niobium, molybdenum, tungsten and hafnium, the metal is advantageously produced.

Ipar reduction, with hydrogen, of the corresponding halide.

When heating outside of that possibly produced by the reduction reaction proves necessary, it is advantageous to make use of an electric arc, an arc plasma or inductive plasma torch, a image or of a laser beam, j Figures 3 and 4 relate to a third embodiment of an essential part of the pro-! ! yielded and the installation according to the invention which presents: the advantage of making it possible to obtain a very high production yield of the metal to be produced, this process is characterized by the fact that the reactants in the gaseous state in the reaction zone, mistletoe is located u.-ns the upper part 2 ′ of the ingot mold 2, according to a vortex current. Thus, fine metal droplets formed in this current t j unite by collision to form more luminous drops. The latter are then projected under the effect of the centrifugal force produced by this movement always! billonnaire, out of the current to agglomerate on / W "· / I / 1 i i i '1 10 ί t i the side walls of the ingot mold and flow there by gravity to join the layer 16 supernatant ingot 17.

This has the great advantage of obtaining a very rapid, continuous and also very thorough separation of the metal produced from the reactants and gaseous reaction products.

A very simple way to create this vortex movement of the gas stream in the reaction zone is to introduce the gas reactants into the latter in directions inclined relative to the vertical so as to form a circular current, or. in a helix.

In the embodiment shown in | Figures 3 and 4, each of the two reagents is introduced! ,.

! in the upper part 21 of the simultaneous ingot mold | ment in several places so as to create, on the one hand, a high flow rate of the reagents and, on the other hand, in [minimum time, a mixture and as intimate contact as possible between the different reagents.

In addition, to create this circular or helical current. Each of the tubes 10 and 15 ends in the reaction zone in the form of arms (e.g. two) provided with injection nozzles 10 *. 10 ", 15 ', 15" which are oriented ί in directions located in planes tangent to | coaxial cylinders with the mold 2 and having horizontal components oriented in the same circular direction.

I These injection ports are located in or slightly below a cover 21 which sealingly closes the upper part 2 ′ of the mold and which 1 is provided with a device 4 intended to allow evacuation i / //

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11 of the reaction products other than metal.

Below are given some practical examples of the preparation of reactive metals according to the process of the invention.

Example 1.

Titanium was produced by the reaction of titanium chloride using sodium in the installation according to FIG. 1.

The reducing metal, therefore formed by% sodium, was kept in the enclosure 11 at a temperature of the order of 150 ° C, or approximately 50 ° C above the melting point, by means of the oven 12 which is-.ide preferably consisting of an electric resistance oven.

| The temperature of the whole upper part 2 ′ was maintained at a value greater than the temperature! boiling point of the reagents, in particular of the order of 1,100 ° C.

The relative amounts of sodium and titanium chloride introduced into this upper part! 2 ′ of the mold were adjusted by acting on the flow rate of the positive displacement pumps 7 and 13.

Titanium chloride being liquid at room temperature, it required no heating-I% fage in the enclosure 5, so that the oven 6 could be put out of service.

Before injecting the reagents, the chamber 1 was first degassed several times by placing it i i under vacuum and ensuring a sweep of argon by the tube 20 at atmospheric pressure or slightly higher than the latter.

| The total reagent flow was adjusted t i so as to ensure, in the reaction zone of the, / 7, i s / / /

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j 4 12 upper part 2 ′ of the ingot mold, a temperature higher than the melting temperature of the metal (1688 ° C.) or of the order of 1750 ° C.

The hourly throughput of titanium chloride was 2.6 m3 (4.4 tonnes) and sodium was 2.7 tonnes. This reagent report a. thus ensured a 25% excess of sodium which mistletoe favored the reaction.

The heat of reaction was sufficient to maintain the temperature of 1750 ° C in the reaction zone.

The cooling of the ingot mold 2, which is therefore constituted by a copper cylinder, or one of its alloys, with a double wall inside the laguelle circulating a coolant, has been adjusted so as to maintain a layer of metal liquid product at the top of the ingot. The temperature of this liquid metal was kept 15 to 30 ° C above its melting point.

It was thus possible to produce one tonne of titanium per hour in the form of a homogeneous and solid ingot which can be subjected directly to forging and rolling.

The metallurgical yield was close to 90%.

During this reduction, the fumes gradually left the reaction zone. They contained gaseous sodium chloride, titanium subchlorides and excess sodium. These gases were conveyed to a condenser in which the complete reduction of the metal was completed at low temperature, thus forming dendrites which were reinjected into the liquid layer of the metal formed above the ingot. / / · / / / *. (!?! J i 13 i'i (

The ingot molds used have diameters between 80 and 160 mm and heights between 200 and 400 mm.

1 When the ingots have a diameter of 150 mm they are extracted at a speed of the order of 210 mm per minute, while those which have a diameter of 100 mm are extracted at a speed of 470 mm per minute, for the flow rates indicated above.

Example 2.

Titanium was produced by simultaneous reduction of titanium chloride using sodium and hydrogen.

I The installations shown diagrammatically in FIG. 1 1 and in FIGS. 3 and 4 have been used, always completed! however by a hydrogen plasma torch not shown! * i feel.

j 4.4 kg of titanium chloride gas, 2.7 kg! • d of gaseous sodium and 1.2 m3 of hydrogen per hour have been | introduced into the reaction zone in which a | temperature between 2450 K and 3570 K and preferably 3000 K has been maintained.

I Excess hydrogen has been recycled.

I The conditions regarding the temperature of i. reagents and the reaction zone -, as well as I the injection method were identical to those of I example 1.

I The quantity of titanium produced per hour h | was around 1 kg.

I On this reduced scale, due to the per-! your important thermics, an additional heating was: I proved necessary.

| Although this auxiliary heating could be carried out either by an electric arc, or by an image furnace, by a laser beam or by any other suitable device, an effective solution was the use a hydrogen plasma torch.

Indeed, the plasma gas is a titanium chloride reducer and it was thus possible to simultaneously reduce the titanium chloride by sodium and hydrogen.

The reduction by sodium is exothermic while the reduction by hydrogen is endothermic; consequently, the fact of carrying out the two reactions simultaneously has the effect that, if it happens that the reaction temperature varies, one of the two reactions will always be favored and the overall metallurgical yield will therefore be greater than the yield of each of the two reactions taken separately, i Example 3.

| Zirconium was produced by reduction of f! zirconium tetrachloride using sodium.

[! Since the zirconia tetrachloride is not liquid, an installation of the type shown i in FIG. 2 a is used.

! Zirconium tetrachloride sublime in | effect at atmospheric pressure at 331 ° C.

Sodium was brought to a boil in; the enclosure 14 by the oven 9 before being injected, by means of the tube 15, into the upper part 2 ′ of the ingot mold 2, while the zirconium tetrachloride has been sublimated in the enclosure 5 by heating with medium oven 6.

The gas flow rate of this halide was imposed by the power dissipated by this furnace 6.

9 kg of zirconium per hour were thus prepared by the reduction of 23 kg of zir tetrachloride ~! 1 15 d.

conium with 5 kg of sodium.

The reagent ratio ensured a 25% excess of sodium.

The other conditions were identical to those of the preceding examples, except that the flow rate of the reactants was such as to ensure in the reaction zone a temperature higher than the temperature of fu! zirconium ion (1860 ° C), of the order of 1900 ° C.

; . Example 4.

Tantalum was prepared by reduction of tantalum chloride using hydrogen.

Since it is a very refractory metal, the development of this metal in the liquid state requires. temperatures above 3000 ° C.

Generally, metallothermic reduction

Ich chloride does not provide enough calories to reach this temperature; moreover, the exothermic reaction has a very low metallurgical yield at very high temperatures.

Thus, in the present case, a hydrogen plasma torch had proved particularly suitable for the supply of these calories.

Indeed, it was found, on the one hand, that the high temperature necessary for the melting of the metal was easily reached and, on the other hand, that the re-I duction by hydrogen was favored by the temperature. -% re high, this reduction being an endothermic reaction migrates.

"I Tantalum being liquid between 3000 ° C and; at 5000 ° C, the temperature in the reaction zone was /, 1 kept close to 4000 ° C. /.

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In addition, the tantalum chloride melting at around 220 ° C, it was in principle possible to impose the flow rate by means of a positive displacement pump.

However, the temperature range where the tantalum pentachloride is liquid being restricted (approximately 20 ° C), it was preferable to impose the gas flow rate of this chloride by the power dissipated by the oven 6, according to the embodiment shown in Figure 2 and as set out in Example 3 above.

These reaction conditions have thus made it possible to produce 1 kg of tantalum per hour by reducing 2.1 kg of tantalum pentachloride per 1.2 m3 of hydrogen, this mistletoe has ensured a significant excess of reducing agent (the molar ratio H2 / TaCl5 = 10).

The excess hydrogen has been recycled for reduction.

The metal was solidified in the cooled copper mold, as in the previous examples.

i 3 As follows from the above, it is essential that the reagents are introduced in the gaseous state directly into the upper part of the flue-line and, eg, not in a separate reaction chamber ♦ 1 '.

i It is understood that the invention is not | not limited to the embodiments described above and that many variants can be envisaged without departing from the scope of this patent.

j This is how these reactive metals can be prepared pure or alloyed with other reactive elements; or not, such as Titanium-Aluminum-Vanadium / alloys.

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Claims (19)

1.- Process for the production of reactive metals, alloyed or not, by the reaction of their halogens; i res, in particular chlorides, with a reducing agent, at a temperature higher than the melting temperature of the metal to be produced, characterized in that it consists in solidifying the produced metal while maintaining in the reaction zone, where the reaction, a layer of this metal in the liquid state at a temperature above the boiling or sublimation temperature of the other reaction products, at the pressure at which the reduction takes place, these other reaction products being evacuated substantially in continuous in the gaseous state. 2.- A method according to claim 1, characterized in that it consists in maintaining the layer of the metal I j produced in the liquid state above the solidified metal, this; j last in the form of an ingot which is extracted substantially continuously, as and when | processing of said metal. 3. Process according to either of Claims 1 and 2, characterized in that the reactants formed by the halides and the reducing agent are introduced into the above-mentioned reaction zone in the gaseous state. 4. Method according to any one of claims 1 to 3, characterized in that the reactants are introduced into the reaction zone in a vortex current, so as to allow the coalescence of the droplets of liquid metal formed by the reaction in this current and subject them to a centrifugal force. . I // j // I ^ ï „tkl> 5, - A method according to claim 4, charac- terized in that gu1on introduces the reagents in the i reaction zone in a direction inclined relative to I port vertically. 6. Method according to one or other of the re vendications 4 and 5, characterized in that one introduces | . the reagents in the zone, reaction following a current i! substantially circular or helical. j. 7.- Process according to any one of the claims 1 to 6, characterized in that the above-mentioned reaction zone I is formed in the upper part of a ί | ingot mold, where a layer of the elaborate metal is maintained | in the liquid state. 8.- Method according to claim 7, charac-. which is achieved by centrifugal force, agglomerating metal droplets produced in the vortex on the side walls of the mold. i 9. Method according to any one of claims 3 to 8, characterized in that at least one of the reactants is heated, in a first step, above its melting temperature, and, in a second step, at the boiling point of the reagent or a temperature above it, said reagent being transferred, substantially continuously, from the first step to the second step, for example by means of a positive displacement pump. 10, - Method according to any one of claims 1 to 9, characterized in that, for reagents which sublimate at atmospheric pressure, the flow rate of these is adjusted towards the reaction zone by controlling the calories supplied to said reagents . / / - t:! 19 I. . 11. Method according to any one of the claims 1 to 10, characterized in that, in particular for relatively weak refractory metals, such as titanium, zirconium, thorium, vanadium, chromium, cobalt, aluminum, silicon, magnesium and uranium, the reduction reaction is carried out under conditions such as calories to maintain the re- zone! action at the above temperature are essentially provided by the exothermic reaction between the halide-nure of the metal to be produced and a reducing metal, such as an alkali or alkaline-earth metal. 12, - Process according to any one of Claims 1 to 8, characterized in that the metal to be produced is separated by simultaneous reduction of the halide from the latter by a reducing metal, such as an alkali metal or alkaline earth, and hydrogen. 13. A method according to any one of Claims 1 to 10, characterized in that the metal is produced by hydrogen reduction of the halide thereof. 14.- Method according to either of claims 12 to 13, characterized in that one provides, in the reaction zone, a supply of external calories by means of a hydrogen plasma torch. j 15.- Process ρ ..- ur the production of metals | reagents by reduction of their halides, such as de- *! crit above or illustrated in the accompanying drawings. A * · i- | 16.- Installation for the production of metals! 1 dl reagents by reduction of their halides, in particular lj | for implementing the method according to any one of the preceding claims, characterized in that it | includes a device for introducing, in the gaseous state, /. reagents participating in the abovementioned reduction in the upper part of a cooled ingot mold, and a device for the continuous evacuation of the gases coming from the reduction. 17, - Installation according to claim 16, characterized in that it comprises a device for maintaining in the upper part of a cooled ingot mold a substantially inert atmosphere. 18, - Installation according to either of claims 16 to 17, characterized in that the device for introducing the gaseous reactants into the upper part of the ingot mold comprises, for each of the reactants, at least one injection tube ending, in a direction inclined with respect to the vertical, in or above the upper part of the mold, so as to form in this part, by these reagents, a substantially swirling current making it possible to project, by a centrifugal force thus created in this current, drops of metal produced outside of it. 19.- Installation according to claim 18. characterized in that the aforesaid device, for é- | gas evacuation from the reaction, includes | means for sucking, out of the upper part of the j, ingot mold, these gases in a direction different from that of the aforementioned centrirn ^ c force. i 20. Installation according to any one | of claims 16 to 19, characterized in that the positive means for introducing the reagents into the upper part; of the ingot mold comprises, for each of the reagents; intended to be introduced in this part, at least. / /! -V »“ if: H. I * / ... I; 21 a chamber preheating for introducing the reactants in the gaseous state therein. 21. Installation according to claim 20, | characterized in that the device for introducing the | reagents in the upper part of the ingot mold com takes, for at least one of the reagents, two enclosures in 'series linked together by transfer means,,! such as a positive displacement pump, heating means being provided for each of the chambers, a first chamber being intended to bring the reagent to the liquid state, the second chamber being intended to bring the liquid reagent coming from the first chamber to the state of-! fear and being connected to the upper part of the linen gutter. 22.- Installation according to any of the | claims 18 to 21, characterized in that the tubes | of injection of the reagents open in a located place; substantially close to the side wall of the lin-! gutter and following directions located in planes 1 tangent to cylinders coaxial with the mold, these dd I directions having horizontal components oriented in the same circular direction. 23.- Installation according to any one of claims 16 to 22, characterized in that it comprises a cover â'adaptant, substantially sealed, on the upper part of the mold. 24, - Installation according to claim 23, characterized in that the injection tubes open into the cover. 25. Installation according to any one; Claims 16 to 24, characterized in that it comprises a heating device for supplying calories to the reaction zone in the upper part. J .d ë «.. r re of the ingot mold and / or to maintain part of the metal J produced in the liquid state in this part of the ingot mold. 126.- Installation according to any one of claims 16 to 25 / characterized in that means are provided for displacing the ingot in the ingot mold as the metal is produced at the entrance to the latter. I ’27.- Installation for the production of this reactive metals 1 as described above or shown in the accompanying drawings. j] 28, - Metal or alloy produced by carrying out the process and / or installation as described; f above or shown in the accompanying drawings. !? He | : ssins: ........... plancivas i αα. pages including Λ map paae I "λ î ....... description pages i ........ é claims pages \ ..... due abridged description Luxembourg, le g ***" · Jl The representative: / / Il ^ Charles München I * 7 Il 'ii | F $ j