DE1533053C - Process for the production of pure beryllium - Google Patents

Description

1 2

The invention relates to a method for producing mineral base, in particular to a 20% weight content

of beryllium with a very low content of diluted potassium hydroxide solution at 20 ° C or through

impurities, especially iron. Take away the metallic solvent through a

The removal of impurities from beryl metal can be done.

lium, especially of iron, has a favorable 5 The latter can be used at low temperatures with

Influence on the mechanical properties of the formation of magnesium or zinc as a metal in front of them

tails. Very low levels, especially of iron, go. Take away can also be done at one of the

are difficult to reach because the iron is very close to the melting temperature of beryllium.

Beryllium sticks. For example, not even ratur can be made, and that with the liquid

one of the best cleaning methods, the zone i ° beryllium immiscible in the presence of aluminum

melt, a very effective removal of this metal, which is strong at working temperature

impurity. The distillation or sublimation of / has affinity for aluminum, obtained very pure

a hot wall seem effective for removal and can be of high density compared with

of iron, however, this process can only be carried out using liquid beryllium, preferably

difficult to carry out because of the risk of contami- 15 antimony.

nations through the extremely reactive that the solvent at low temperature with-

Beryllium vapor. taking metal is in excess in the

While after the previously known method of the first separation liquid is introduced, the content of the beryllium of impurities is kept constant for one hour only up to the temperature, could be reduced to a few tenths of a percent, 3 ° is then filtered and optionally with diluted the aim of the invention preparation of pure potassium hydroxide solution and then with concentrated SaI beryllium peter acid according to the different requirements washed at about 75O ⁰ C in vacuo stanchions practice, particularly with a below distilled to give the metal to a radiator of thousandths percent (at a few ppm = Parts per precipitate, and finally a melting of the million) weight content of iron or beryllium carried out in a vacuum, which removes the last -other metallic or metalloid impurities traces of this metal;
by means of a process that is easy to carry out, the use of which can be generalized to take away at high temperature, in particular metal is introduced by casting into the mixture obtained after the first separation, also in order to follow a thermal reduction, which under Argon ion of a beryllium compound pure beryllium at 3 ° protective atmosphere to a temperature slightly above the melting temperature of the beryllium.

That has been brought about to solve this problem according to the invention. For several minutes the proposed method for the production of stirred, then allowed to settle, cooled, given beryllium with a very low content of impurities the obtained beryllium gang product used contaminated beryllium metal melted in a vacuum, whereby the last traces of tall, especially impure commercial (technical) of this metal are removed,
sches) beryllium. or a beryllium-aluminum alloy The recycling of the metallic solvent alloy, in liquid aluminum or a liquid in the circuit, if the removal of the solution alloy of aluminum and at least one of the 4 ° means was carried out at low temperature, elements silicon, zinc and magnesium dissolved, by combining the filtrates in a crucible, by fractional crystallization a first separation of addition of the entraining metal melting, holding by filtration carried out on it by a lying at an approximately 25 ⁰ C above the liquidus second separator stage, with the aluminum or the temperature and filtering, in particular all of the impurities in aluminum oxide are effected by means of Gesin aluminum alloy. ,. _
If the removal of the solvent is produced at a desired very pure beryllium and if necessary the aluminum is recovered at a temperature above the melting temperature of the beryllium, the recovery and return cycle is carried out. guidance of the metallic solvent through Va-

Commercially available Beryl vacuum distillation of the filtrates at HOO ⁰ C. can be used as the starting material.

lium in the form of electrolysis flakes, in particular the invention is explained further . through the

remelted flakes, or in the form of the following description.

Shot or powder, as well as in the form of aluminum investigations have led to the assumption that

minium-beryllium alloy, which is a good solvent for contaminants, in particular due to the fact that aluminum

thermal reduction of an original beryllium gradient of beryllium, especially for iron, im

Connection by an excess of an aluminum temperature range below 1000 ⁰ C is. Microphoto

connection obtained can be used. graphical studies show that the iron itself

The liquid aluminum and the liquid alloy accumulate on the grain boundaries. Besides, this is of aluminum with at least one of the elements aluminum practically insoluble in solid beryllium, Silicon, zinc and magnesium will subsequently be 60 and the eutectic Al-Be is about 2.5 atomais metallic solvent called. percent, beryllium at 645 ° C.

The aforementioned fractional crystallization is slowed down by the principle of the method according to the invention Cooling down to a little above is in it, the impure beryllium in liquid AIu-645 ° C causes lying temperature limit. To dissolve the erminium (or an aluminum alloy) The first separation stage mentioned can preferably be followed by the pure beryllium from the liquid in a 65 simple filtration or centrifugation. either by cooling or by reducing

The mentioned second separation can either be achieved by reducing its solubility in liquid aluminum

selective chemical attack by means of a thinned one by adding a third element

3 4

and finally that loaded with the impurities. The composition of the eutectic Al-Be-Mg

Cut off aluminum or the aluminum alloy. is:

The commercially available (technical) beryllium in Be: 0.165 atomic percent
sweet form (raw or remelted elec- Mg: 52.7 atomic percent
trolysis leaves, grist or powder) the aluminum 5 γ _: 449 ⁰ C
minium or an aluminum alloy selected according to the criteria given below in one. The beryllium content is added in comparison with the amount not more than 20 atomic percent. This reduces the content of the eutectic Al-Be, and the aim is to increase it in the range of the amount of beryllium that crystallizes out. Precipitation of iron at the moment of crystalline 1 ° The composition of the eutectic Al-Be-Zn sation remains favorable temperatures. The batch is not known, but it can be said that the zinc is brought to 1200 ^° C. and at this temperature the melting temperature is considerably reduced. Its dissolution occurs quickly. As soon as the solution has become a homogeneously higher density that favors the settling of the beryllium, it is allowed to crystallize. and consequently filtration.

By cooling down to a little over the 15 zinc and magnesium also have a high

Temperature of the eutectic Al-Be, ie 645 ^° C., vapor pressure. This property can be used with advantage

The beryllium is crystallized at a certain temperature. exploit in the second stage of the elimination of the

The first crystals form around 1000 ^° C., the solvents.

last are in equilibrium with the 2.5 atomic percent To completely eliminate the remaining lo-

Beryllium containing eutectic phase. The size 2 ° solvent two measures are applied,

of the crystals is of great importance for the later namely the selective leaching out on chemical

Procedural stage. Too fine crystals must avoid walking and taking the solvent through

will. You therefore slowly cool down / for example a third metal.

the temperature is used for an hour slightly below During selective chemical leaching

of the liquidus held and so the number of formed »5 one makes a difference in the speed of the

Crystal nuclei limited. The cooling is within attack of dilute mineral bases on beryllium

4 hours completed. The obtained dendrites and aluminum (or the alloys used),

of beryllium then have a length of the size- The beryllium, is passivated while the

Order of-millimeters. Dissolves aluminum. For example, to 20 ° / ₀

Since the vapor pressures of beryllium and aluminum 3 »weight content dilute potassium hydroxide solution

are very close to each other, a separation by 20 ⁰ C aluminum and magnesium is quickly on, however

Vacuum distillation not possible. Also there is practically no beryllium.

The densities do not differ enough to allow the solvent entrainment To enable separation by pouring. either at low temperature or at a temple a first stage is a large excess 35 temperature above the melting point of beryllium by of the liquid eutectic Al-Be on mechanical entrainment of the solvent by a third Removed way, namely by simple filtration or metal can be made.

Centrifuge. If you have the beryllium in pure Take away at a low temperature it will be

If aluminum has dissolved, however, you cannot do more than the aluminum surrounding the beryllium crystals (or

60% aluminum. based on weight. 4 ° the alloy) with a renewed filtration through a

This value can therefore not be exceeded, metal entrained that meets the following conditions

since in the tangle of beryllium dendrites there is a liquid: it must be very light with the aluminum

remains closed. liquid eutectic with a low melting point

To increase the efficiency of the filtration form; it must and may be easily meltable itself

an alloy of aluminum beryllium cannot be dissolved as a solvent at the working temperature;

minium with a fluidity increasing it allows the elimination of the dissolved in aluminum

Use metal. This metal must not be contaminated with beryllium by precipitating the same

neither a fixed solution to it at the moment of encroaching; it has to be completely simple

Crystallization not to contaminate, nor a way, for example by distillation or a

form bond to the separation of the impurities- 5 ° chemical attack, which the beryllium ^ intact

the beryllium, especially iron, cannot be eliminated; Furthermore, it must itself be proportionate

to affect. Furthermore, this metal, if moderately pure, does not have to be distilled off

possible to leave both the melting point of the eutectic impurities behind. The selection in

Al-Be and at the same time the beryllium content of the with regard to these properties leads to the metals,

Decrease eutectic. Furthermore, it must be slightly different from the 55 already used to favor the first filtration.

to be separated. with the exception of silicon, the one

Silicon, zinc and magnesium increase the liquid's melting point too high, thereby reducing its de-

of aluminum. Neither forming a fixed distance would be difficult. Magnesium and zinc, however

Solution still a connection with beryllium. For example, they are well suited. So if you have the

lower the melting point of the eutectic Al-Be. 60 using the first two stages of the procedure

The eutectic Al-Be-Si lies with: «" ^he has carried out the Al-Mg alloy

Filtration at a temperature close to

Be: 4.6 atomic percent at 650 ° C. The filter is then interrupted

Si: 11.6 atomic percent and admits such an amount of magnesium that

T: 572 ° C 65 unites the composition of the liquid obtained

Has excess magnesium. The temperature is

The silicon favors the deposition of iron, held for 1 hour, then filtered. the

by association with the aluminum. Experience shows that you can use two extractions with

Magnesium can remove aluminum. You then need to submit at about 750 ⁰ C, only the residual mass of Berylliumdendriten and magnesium vacuum distillation. The magnesium is deposited on a cooler. This distillation can be followed by melting the beryllium in a vacuum, which removes the last traces of magnesium. However, the beryllium crystals can also be washed beforehand with dilute potassium hydroxide solution and then concentrated nitric acid. If the aluminum is taken away at a temperature above the melting point of beryllium, the aluminum is separated by distribution between two liquid metallic phases, beryllium and an additional metal that has the following properties: It must be practically immiscible with liquid beryllium even in the presence of aluminum being; it must have a high affinity for aluminum at the working temperature; it must be available in very pure form in order not to contaminate the beryllium again; it must have a high density compared to liquid beryllium to facilitate pouring. Antimony was used, but other metals are suitable. Antimony has a high vapor pressure, so it. can be purified by distillation or sublimation. In addition, the last traces of antimony, which could contaminate the beryllium, can easily be removed by final melting in a vacuum. The Al-Be mixture obtained after a first filtration is brought to a temperature slightly above the melting temperature of beryllium under an argon protective gas atmosphere. The antimony is then poured in in sufficient quantity to effect a separation into two phases. In this way, the evaporation losses of antimony are limited by the amount above it

ίο protective layer made of liquid beryllium. Besides that stir vigorously for a few minutes and then let sit. The pouring takes place slow because of the high viscosity of liquid beryllium. One receives after cooling one from Major part of the aluminum freed beryllium mass. A second extraction may be required. The beryllium obtained is then melted in vacuo a second time, to make the last To remove traces of antimony.

ao As an example, the following are the cleaning of a commercial (technical) beryllium results obtained, with the removal of iron in the course of the purification steps by means of irradiation with thermal new

a5 trons activated iron isotope Fe ₅₈ would be followed. The concentrations (in ppm) of the main impurities in the starting product were as follows:.

Al Fe Cu Si Mg Ni Mn. C. Be ...
Al .... 30th 10 to 50
45 4 to 8
35 10 to 25
6th 10 to 20 10 to 30 15th 170

B e i s ρ i e 1 I

90 g of 0.81 atoms per million Fe radioactive contaminated _sg beryllium are dissolved in 1200 g of aluminum, which thus has a weight content of 7% beryllium.

This operation is carried out at 1200 ⁰ C in the for. Filtration is carried out in certain crucibles, the bottom of which is connected to a pumping system.

When the bath has reached a homogeneous composition, it is slowly cooled (in 5 hours) to 70O ⁰ C and filtered by applying a vacuum below the crucible.

a) Filtration of the aluminum

Weight of the filtrate No. 1,850 g

Filtration residue weight

No. 1 440 g

Beryllium content of the filtrate (based on

by weight) 1.4%

The beryllium loss is therefore 11g. The filtration residue contains 18 ° / o beryllium (by weight).

b) Removal of aluminum by magnesium

206 g of residue no. 1, which thus contained 37 g of beryllium, were ^{treated at 650 °} C. with 100 g of magnesium in an aluminum oxide filter crucible.

It is kept at this temperature for 3 hours and then filtered:

Weight of filtrate No. 2 210 g

- Beryllium content of filtrate No. 2

(based on weight) .. <0.5%

Beryllium loss so .............. ^. 1.5 g

The residue is treated again in the same crucible, but at 700 ° C., with 60 g of magnesium. The mixture is kept at that temperature for 2 hours and then filtered.

Weight of the filtrate no. 3 _: lllg

: Weight of residue No. 3 45 g

Beryllium content of filtrate No. 3

(based on weight) 0.18%

Beryllium loss accordingly 0.2 g.

c) Removal of the magnesium

_go made Distillation of Magnesiums.wird contained in the residue no. 3 at 700 ⁰ C in vacuo. The magnesium is deposited on a cooler. The process takes 3 hours.

Weight of the distillate 8.5 g

Weight of residue 36.5 g

Beryllium content of the distillate

(based on weight) 0.064%

Beryllium loss accordingly 0.5 g.

The residue is then with dilute potassium hydroxide solution and then with concentrated Nitric acid washed and finally rinsed:

Weight of residue before

Melting in an argon atmosphere 35 g

Weight of the beryllium finally obtained 34 g

Beryllium yield:

Final weight Be _{inn O10} .

99.13 percent by weight Al and 0.87 percent by weight Be assumes.

The one through the relationship
Initial weight Be - eutectic losses

Initial weight
defined yield is therefore

• 100

10

Initial weight Be

7.7-0.81
7.7

100 = 98.5%.

Example II

g of residue no. 1 containing about 31 g of beryllium is 20 percent by weight Potassium hydroxide solution treated.

Duration of treatment: 70 hours

Weight of Beryllium Recovered:

28.2 g.

Weight of the beryllium contained in the treatment liquor: 2.7 g, i.e. H. 8.7% of the residue No. 1 contained beryllium.

Weight of the beryllium after melting under an argon atmosphere: 27 g

Beryllium yield:.

"Final weight Be

Initial weight Be

The following. Comparison table combines the analysis results obtained in the above two examples:

Be starting product

0.81
10

Be end product example 1

0.04
330

Be end product example 2

0.06
400

The degree of purification with regard to iron is given by

Initial concentration Fe ₅ ,

45

Final concentration Fe ₅ ,
and amounts to

0 81

in example 1: - ^ - = 20,
0.004

in the example: —'—- ■ - = 13.
0.06

In the following, the beryllium yield during purification is considered.

The main loss of beryllium is due to the composition of the liquid at the filtration temperature definitely. When this temperature is close to the eutectic temperature, the beryllium content is approximately the same as that of the eutectic. If you get 20 atomic percent beryllium in 80 atomic percent Aluminum, i.e. 77% or 92.3% based on weight, dissolves, is the beryllium loss After all, you can recover the aluminum and the dragging metal and

»5 run back. The filtrates obtained from the various filtrations consist of aluminum, beryllium, the entrainment metal used and impurities.
If the temperature is below the beryllium

ao the melting point remains, the operation consists of to separate the impurities from the alloy carrying aluminum and the two to separate the latter from each other. The filtrates are combined in one and the same filter crucible on top

he adds so much of the entrainment • metal used until its proportion is 35% ^{in the} case of magnesium and 95% in the case of zinc. You melt it, then hold it

. Temperature Jfiei 20 ⁰ C or 30 ⁰ C above the liquid

30 · dus'Temperatur, so 570 or 400 ⁰ C and filtered, for example by sintered alumina. The fine precipitates of the impurities as well as the excess beryllium are retained on the filter while a cleaned alloy Al - carrying metal is collected. The two metals are then separated by distillation at 800 ^° C. in vacuo.

If the temperature is above the Berylliumschmelzpunkt, the applied alloy Al-Sb is subjected to vacuum distillation at HOO ⁰ C. In this way, the antimony freed from aluminum and non-volatile impurities, in particular iron, is recovered and is ready for reuse.

92.3 x 0.87
99.13

= 0.81% (based on weight).

If one considers the composition of the eutectic

Claims (11)

Patent claims: 1. Process for the production of beryllium with very low content of impurities, in particular on iron, characterized that a contaminated beryllium metal used as a starting product, in particular contaminated commercial (technical) beryllium or a beryllium-aluminum alloy, in liquid aluminum or a liquid alloy of aluminum and at least one of the elements silicon, zinc and magnesium dissolved, after fractional crystallization one first separation carried out by filtration, then through a second separation stage, with the aluminum or the aluminum alloy, the entirety of the. Carried away impurities and is separated, the desired very pure beryllium is produced and optionally the Aluminum is recovered and recycled. 2. The method according to claim 1, characterized in that the fractional crystallization by 009 641/90 slow cooling down to a limit just above 645 ° C is effected. 3. The method according to claim 1, characterized in that the first separation stage is a simple one Filtration or filtration by centrifugation. 4. The method according to claim 1, characterized in that the second separation stage consists in a selective chemical leaching at 2O ⁰ C by means of a dilute mineral base, in particular potassium hydroxide solution diluted to 20% by weight. 5. The method according to claim 1, characterized in that that the second separation stage in a take-away of the solvent through a metal consists. 6. The method according to claim 5, characterized in that the entrainment at a below the melting point, the beryllium lying temperature and the metal magnesium or Zinc is. 7. The method according to claim 5, characterized in that the take away at one of your Melting point of the beryllium occurs and lies as a metal with liquid Beryllium is immiscible in the presence of aluminum, at a working temperature has a great affinity for aluminum, can be kept very pure and in comparison with liquid beryllium has a high density, preferably antimony is used. 8. The method according to claim 6, characterized in that the metal, which entrains the solvent at low temperature, introduced in excess of the liquid obtained in the first separation stage, the temperature kept constant for one hour, then filtered, optionally with dilute potassium hydroxide solution and then washed with concentrated 'nitric acid, a vacuum distillation at about 75O ⁰ C, the metal is deposited on a condenser in the course of which, carried out and finally the beryllium in vacuo to remove the last traces of the metal is melted. 9. The method according to claim 7, characterized in that the metal is taken for entrainment high temperature by pouring into the obtained after the first separation stage, under argon protective gas brought to a temperature slightly above the melting temperature of beryllium Introduce mixture and stir vigorously for several minutes, allow to decant, cool, if necessary undertakes a second sequence of corresponding operations and then the received The last traces of the metal are removed from beryllium by melting in a vacuum. 10. The method according to claims 1 and 9, characterized in that the recovery and Recirculation of the metallic solvent in the event that the solvent is taken along takes place at low temperature, by combining the filtrates in a filter crucible, adding the entrained metal, melting and then maintaining the temperature at about 25 ° C above the liquidus, and filtering, especially-through sintered alumina. "' 11. The method according to claims 1 and 10, characterized in that the recovery and recycling of the metallic solvent in the event that the removal of the solvent takes place at a higher temperature than the melting temperature of the beryllium, carried out by vacuum distillation of the filtrates at HOO ⁰ C. will.