Apparatus for preparing high melting point high toughness metals

A hermetically closable and evacuable apparatus for preparing high melting point high toughness metals by reduction of a chloride of said metals comprising a heatable reaction chamber and a coolable condensation chamber provided above the reaction chamber which chambers communicate with each other through an intermediate connecting section, wherein the intermediate connecting section is provided with a seal pot closing means comprising a funnel body and a pan which can be opened to form a wide gas passage, is disclosed.

TECHNICAL FIELD OF THE INVENTION 
This invention relates to an apparatus for reduction of metal chlorides. 
Among metallic materials, titanium and zirconium, which have high melting 
point and high toughness, are produced mainly by reduction of a chloride 
thereof with magnesium and obtained in the form of metal sponge. 
BACKGROUND OF THE INVENTION 
For the production of these high melting point high toughness metals, a 
hermetically closable and evacuable apparatus comprising a heatable 
reaction chamber and a coolable condensation chamber provided above the 
reaction chamber communicating each other with an intermediate connecting 
section is used, and magnesium and a chloride of said metals (titanium 
tetrachloride, for instance) are reacted in the reaction chamber, the 
formed magnesium chloride and unreacted magnesium are removed from the 
formed sponge metal by vacuum distillation, and the magnesium chloride and 
the magnesium are recovered in the cooled condensation chamber. 
Such an apparatus is disclosed in Japanese Laying-Open Patent Publication 
No. 18717/72, for instance. In the apparatus of this kind, a problem 
arises concerning how to close the passage between the reaction chamber 
underneath and the condensation chamber above. In the apparatus disclosed 
in said patent publication, the passage of the intermediate connecting 
section is closed by a lid. But the mechanism of the lid is complicated 
and the lid is exposed to hot vapors of magnesium and magnesium chloride 
which pass within the proximity of said lid. Thus the lid is deformed by 
thermal strain and gradually fails to provide gas-tight closure. 
A partially improved apparatus of this type is disclosed in Japanese 
Laying-Open Patent Publication No. 49922/77. In this apparatus, a lid of 
fusible metal such as magnesium, aluminum, zinc, or antimony is fixed by 
bolts so as to close the passage during the reduction reaction, and the 
lid is melted by a heating means at the stage of vacuum separation so as 
to open the connecting passage. The defect of the above-mentioned 
apparatus is eliminated by this improvement. But the apparatus is not 
quite satisfactory since a lid of a fusible metal, the surface of which is 
smoothly finished, has to be prepared for every run. 
Both of the two above-cited apparatuses must be hoisted as a whole by a 
crane or the like for removal from the heating furnace and transfer to 
another position, since the two chambers cannot be separated at high 
temperature. This inconvenience will become even greater now that larger 
and larger apparatuses are being employed, since cranes with larger 
capacities and more spacious plant buildings will be required and 
construction cost will increase. This invention is intended to improve the 
efficiency of the above-mentioned apparatus overcoming the defects of 
prior art apparatuses by employing a seal pot structure as the means for 
closing the passage of the intermediate connecting section in an apparatus 
for reducing chlorides of high melting point high toughness metals 
comprising a reaction chamber and a condensation chamber connected by an 
intermediate connecting section. 
We previously proposed an apparatus for producing high melting point high 
toughness metals by reduction of chloride thereof with an active metal 
which comprises a heatable reaction chamber in which the chloride and the 
active metal are reacted, an evacuable and coolable condensation chamber 
in which the active metal and the formed chloride which have been 
separated from the formed metal by evaporation in the reaction chamber are 
condensed, and an intermediate connecting section for communicating or 
cutting off the two chambers. The apparatus is characterized in that the 
intermediate connecting section is provided with a seal pot comprising a 
funnel body and a pan which receives the lower pipe of the funnel body and 
retains a fusible and vaporizable material and a heating means for melting 
and vaporizing the fusible and vaporizable material. (Japanese Laying-Open 
Patent Publication No. 126936/83 (Patent Application No. 8771/82)) 
However, this apparatus has a defect that the seal pot structure 
constitutes a high resistance to the flow of gases in comparison with the 
other parts when the apparatus is evacuated. The present invention has 
eliminated this defect. 
DISCLOSURE OF THE INVENTION 
This invention provides in a hermetically closable and evacuable apparatus 
for preparing high melting point high toughness metals by reduction of a 
chloride of said metals comprising a heatable reaction chamber and a 
coolable condensation chamber provided above the reaction chamber and 
communicating with the condensation chamber through an intermediate 
connecting section, the improved apparatus characterized in that said 
intermediate connecting section is provided with a seal pot closing means 
comprising an upright funnel body which has an opening of a substantial 
size and is supported by the internal wall of the intermediate connecting 
section at its periphery; a pan which can receive a fusible material 
therein and is pivotable around a rotation shaft secured thereto at one 
end thereof between a receiving position and a pouring position and 
receives the lower pipe of the funnel body when it is at the receiving 
position; and a heating means for heating the seal pot. 
This invention also provides in a hermetically closable and evacuable 
apparatus for preparing high melting point high toughness metal by 
reduction of a chloride of said metals comprising a heatable reaction 
chamber and a coolable condensation chamber provided above the reaction 
chamber and communicating with the condensation chamber through an 
intermediate connecting section, the improved apparatus characterized in 
that said intermediate connecting section is provided with a seal pot 
closing means comprising an inverted funnel body which has an opening of a 
substantial size and is supported by the internal wall of the intermediate 
connecting section at its periphery, and can receive a fusible material in 
the space formed by the funnel and the internal wall of the intermediate 
connecting section; a pan which covers the opening of the funnel and is 
pivotable around a rotation shaft secured thereto at one end thereof; and 
a heating means for heating the seal pot. 
In this specification, the term "funnel body" means a shape comprising a 
pan-like part or conical part and a cylindrical part communicating with 
said pan-like part or conical part. 
In the apparatus of this invention, the seal pot part can be widely opened. 
Therefore, the resistance to gas flow at the time of evacuation is 
remarkably reduced, the operation time is shortened, and the quality of 
the produced sponge metal is improved. 
The term "seal pot" used in this specification means a seal pot of the 
conventional structure, but it is different therefrom in that fusible but 
normally solid materials are used as the sealant. Sealants usable in this 
invention include low-melting metals such as magnesium, aluminum, zinc, 
antimony; and salts such as magnesium chloride, sodium chloride, potassium 
chloride and mixtures thereof. But metals are preferred since perfect 
sealing is possible and, inter alia, magnesium is most preferred since it 
does not contaminate the produced high melting point high toughness 
metals. 
This invention provides an apparatus for reduction of chlorides of high 
melting high toughness metals which is more convenient to use than the 
known apparatuses of the same type. Today, this apparatus can be used for 
production of titanium and zirconium. However, those skilled in the art 
will find uses for this apparatus if processes for production of similar 
metals by reduction of chlorides thereof with an active metal (sodium, 
calcium, etc., as well as magnesium) are developed. 
Now the invention will be explained in detail with respect to preferred 
embodiments with reference to the attached drawings.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 is an elevational cross section of an embodiment of this invention. 
A reaction chamber comprises an external container or a reaction retort 10 
and an internal container 20 received in the former supported by leg 
members 21. 
The retort 10 can be of any shape, but practically it is cylindrical and 
the internal container 20 is also cylindrical and a little smaller than 
the former. The bottom of the internal container 20 is provided with at 
least one perforation for draining molten magnesium chloride, and the 
bottom of the retort 10 is provided with an outlet duct 15 having a valve 
means 14 for discharge of magnesium chloride. A flange 11 is formed at the 
upper periphery of the retort 10 and a supporting brim 12 is provided for 
supporting the retort 10 in a heating furnace 90 which is explained later. 
An intermediate connecting section 30 is essentially a cylindrical body 31 
having a diameter smaller than that of the internal container 20 of the 
reaction chamber. A large flange 32 extends from the upper periphery of 
the cylindrical body, a brim 33 extends from the lower periphery thereof, 
a cylindrical wall 34 is formed extending upward from the middle of the 
latter, but is shorter than the cylindrical body 31, and from the upper 
periphery thereof a flange 35 extends. The flange 35 is formed so that it 
can be placed upon the flange 13 of the internal container 20 and the 
flange 11 of the retort 10. The diameter of the brim 33 at the lower end 
of the intermediate connecting section is slightly smaller than the inside 
diameter of the internal container 20, whereby with which the brim may 
contact the internal wall of the intermediate connecting section. 
The flange 35 of the intermediate connecting section 30, the flange 13 of 
the internal container 20 and the flange 11 of the retort are placed one 
over the other with gaskets inserted therebetween and detachably secured 
by means of bolts or clamps. Any known heat-resistive elastomer gasket can 
be used. 
The condensation chamber comprises a jacketed cooling container 40 similar 
to the reaction retort in shape and a condensation cylinder 50 contained 
in the former. The cooling container 40 is provided with an exhaust outlet 
41, an inlet 42 and an outlet 43 for the coolant (water), and a flange 44 
is provided at the bottom thereof like that of the retort. The 
condensation cylinder 50 is a container a little smaller than the cooling 
container, the ceiling of which is provided with at least one perforation 
for allowing passage of gas. The lower periphery has a flange 52 like that 
of the cooling container. The flanges 32 of the intermediate connecting 
section 31 and the flanges 44 and 52 of the cooling container 40 and the 
condensation cylinder 50 are laid one over another with gaskets inserted 
therebetween and secured together by means of bolts or clamps. Here again, 
any known elastomer gasket can be used as well. 
A funnel body 38 is provided in the central part of the cylindrical body 31 
of the intermediate connecting section 30. The upper periphery of the 
funnel body 38 is hermetically secured to the inside wall of the 
cylindrical body 31 and the lower pipe thereof is received in a shallow 
cylindrical pan 36. The detail of the structure of the seal pot comprising 
the funnel body and the pan will be explained later. 
Usually the intermediate connecting section 30 is provided with an inlet 
tube 61 for a metal chloride and an inert gas and an exhaust outlet tube 
62. Although these tubes can instead be provided in the retort 10, it is 
convenient that they be provided in the intermediate connecting section 
30. 
Each of the tubes 61 and 62 has a valve at a position not so far from the 
intermediate connecting section 30, and can be cut off from the master 
conduits on the other side of the valves. In FIG. 1, the tube 61 is a 
branched tube for introduction of both a metal chloride and an inert gas, 
wherein each branch tube has a valve. 
An inlet tube 39 for the introduction of a sealant 80 is provided above the 
funnel body 38 of the intermediate connecting section 30. Heating means, 
usually electric resistance wires 70, 71, are provided on the outside of 
the intermediate connecting section 30 and the sealant inlet tube 39. 
The above-mentioned retort, internal container, cooling container, and 
condensation cylinder can be made of mild steel or stainless steel. 
The retort 10 is received in a suitable heating furnace 90. The heating 
furnace is suitably heated by an electric resistance heating means. The 
heating furnace is provided with an opening at the bottom for the outlet 
duct 15 of the retort 10. No further explanation is given of the heating 
furnace since this can be easily designed by those skilled in the art. 
The heating means 70 for the intermediate connecting section can 
conveniently be formed of two semi-cylindrical units (if necessary, three 
units each constituting one-third of a cylinder), which are arranged so as 
to surround the intermediate connecting section. 
The improved seal pot in accordance with this invention is illustrated in 
FIGS. 2 and 3 in a somewhat enlarged scale. 
As shown in FIG. 2, the funnel body 38 comprises a flat disc and a short 
cylinder secured to the periphery of a circular opening provided in the 
disc. However, the shape of the funnel body is not limited to the shape 
shown in this figure but may be formed as a truncated cone and a pipe as 
mentioned above, and illustrated in FIG. 1. 
The pan 36 is simply a container receiving a sealant, but one end thereof 
is secured to a rotation shaft 37 and is swingable between a receiving 
position and a pouring position. The rotation shaft 37 extends across the 
intermediate connecting section 30 and is hermetically supported in the 
wall of the latter. 
As shown in FIG. 3, one end of the shaft 37 is supported by a blind bearing 
37a and the other end thereof is supported by a bearing 37b, which 
comprises a short protruding tube 37b and a hat-like cap 37c. The cap 37c 
is secured to the end of the tube 37b with a gasket inserted therebetween 
by means of bolts or clamps. The gasket may be of a heat resistive resin 
such as teflon. In certain designs, however, a metal gasket will have to 
be used. 
In order to support the pan 36 at the receiving position, a supporting 
shaft 37' is used. The bearing means therefor 37a', 37b' and 37c' are of 
the same structure as those for the rotation shaft 37. The supporting 
shaft 37' can, of course, be drawn out until it is detached from the pan. 
The bearings should be as air-tight as possible (although absolute 
tightness can not be expected). 
The structure of another seal pot of this invention is illustrated in FIGS. 
5 and 6. The structure in this embodiment is that obtained by inverting 
the structure shown in FIGS. 2 and 3. In this case, the sealant is 
received in the upper side of the inverted funnel body, and the pan is 
merely a lid, which is supported on the funnel body. Therefore, no 
supporting shaft is required. The funnel body can, of course, be conical. 
Preferably a gas leak hole 38a is provided. This can be a hole, notch or 
indentation provided in the wall of the funnel body and facilitates the 
pouring of a sealant into the receiving space formed by the funnel body. 
The operation of the apparatus will now be explained with respect to the 
apparatus shown in FIGS. 1 and 2-4. After lumps of magnesium are placed in 
the internal container 20, the flanges 11, 13 and 35 are secured so as to 
attach the intermediate connecting section 30. Further, the condensation 
chamber constituted by the cooling container 40 and condensation cylinder 
50 is attached and thus the entire apparatus is assembled. The setting of 
the condensation chamber is made after the reaction chamber (together with 
the intermediate connecting section) is placed in the heating furnace. The 
assembled apparatus is tested for gas tightness by evacuation through the 
outlet 41. 
After this test, the pan is set in the receiving position, the apparatus is 
evacuated through the outlet 41, and an inert gas is introduced into the 
apparatus through the tube 61 until the inside pressure becomes a little 
higher than atmospheric pressure. Then a melt of a sealant 80 is 
introduced into the pan 36 and is allowed solidify. Then the reaction 
chamber is heated by actuating the heating furnace 90 so as to melt the 
magnesium lumps, and the reaction is allowed to proceed by introducing a 
metal chloride through the inlet 61. After the reaction is finished and a 
sponge metal is formed, the formed magnesium chloride is drained by 
opening the valve 14 of the duct 15. 
Then the valve 14 is closed, and the intermediate connecting section 30 is 
heated by means of the heating means 70. When the sealant in the pan has 
melted, the cap 37c' of the bearing for the supporting shaft is removed 
and the supporting shaft is drawn out. Then the sealant is poured out of 
the pan 36. If necessary, the cap 37c of the bearing for the rotation 
shaft 31 may be removed and the rotation shaft forcibly rotated to 
completely open the pan 36. The removed cap is fixed again. It is 
necessary to introduce an inert gas in order to prevent atmospheric air 
from entering the apparatus. 
Thus a large passage is opened between the reaction chamber 10 and the 
condensation chamber. If heating of the reaction chamber 10 and evacuation 
of the apparatus are continued, the magnesium chloride entrapped in the 
formed sponge metal and the unreacted magnesium are vaporized and 
separated from the metal and are collected in the condensation cylinder 
50. 
After the evacuation separation is finished, the apparatus is allowed to 
return to normal pressure by introduction of argon, the caps 37c and 37c' 
are removed, the pan is returned to the initial position and supported 
there by the supporting shaft 37' again. The sealant 80 is again 
introduced and solidified. The condensation chamber is removed from the 
intermediate connecting section 30 and the reaction chamber 10 (together 
with the intermediate connecting section 30) is taken out of the heating 
furnace 90. After the reaction chamber 10 is cooled, the formed sponge 
metal is taken out. Thus one batch run is finished. 
The passage of the intermediate connecting 30 section is already closed. 
Therefore, for the next run, the reaction can be immediately started after 
magnesium is placed in the reaction chamber 10 and the apparatus is 
assembled. 
The operation is the same for the apparatus shown in FIGS. 5 and 6. But in 
this case, there is no supporting shaft and the rotation shaft must be 
forcibly rotated. 
EXAMPLE 1 
An apparatus as shown in FIG. 1 having the seal pot of the structure shown 
in FIGS. 2 and 3 was constructed. The dimensions were as follows. 
Both the retort and the cooling container were of the bell shape 700 mm in 
outside diameter and 1760 mm in height. The cylindrical part of the 
intermediate connecting section was 370 mm in height and 185 mm in inside 
diameter. 
The retort and the intermediate connecting section (including the seal pot) 
were made of ferritic stainless steel. The retort and the intermediate 
connecting section were made of 25 mm thick plates and the seal pot was 
made of 5 mm thick plates. The seal pot was 108 mm in outside diameter and 
40 mm in height. The funnel body was 68 mm in outside diameter and 52 mm 
in height. The condensation container and the condensation cylinder were 
made of mild steel. The internal container of the reaction chamber was 
also made of mild steel. 
EXAMPLE 2 
An apparatus substantially as shown in FIG. 1 having a seal pot of the 
structure shown in FIGS. 5 and 6 was constructed. The dimensions were the 
same as those of Example 1. 
The retort and the intermediate connecting section (including the seal pot) 
were made of ferritic stainless steel. The retort, the internal container 
of the reaction chamber and the intermediate connecting section, which are 
subjected to heating, were 25 mm in thickness and the seal pot was made of 
5 mm thick plate. The cylindrical part of the funnel body was 80 mm in 
diameter and was spaced from one side of the wall of the intermediate 
connecting section by 75 mm and spaced from the other side of the wall by 
30 mm when measured on the diameter. The height of the cylindrical part 
was 40 mm. The depth of the pan was 34 mm and the diameter thereof was 138 
mm. 
OPERATION EXAMPLE 1 
Following the above-described operation procedures, titanium was prepared. 
First, 371 kg of solid magnesium was placed in the internal container of 
the reaction chamber, and argon was introduced into the apparatus so that 
the internal pressure was a little higher than atmospheric pressure. The 
passage of the intermediate connecting section was closed by introducing 
molten metallic magnesium into the pan, and the retort was heated at 
800.degree. C. so as to melt the charged magnesium. Then about 1000 kg of 
titanium chloride was introduced dropwise into the reaction chamber 
allowing reaction to proceed with care not to allow the temperature to 
rise too much. After the reaction was finished, the apparatus was 
repressurized with argon and the formed magnesium chloride was drained. 
The seal pot was heated and the pan was opened as explained above. The 
molten magnesium sealant dropped into the reaction chamber. 
The reaction chamber was heated up to 1000.degree. C., whereafter 
evacuation separation was started and continued for 30 hours. The 
evacuation was very smoothly effected. 
The seal pot was again closed, molten magnesium was introduced into the 
seal pot and solidified, the condensation chamber was removed, and the 
reaction chamber (together with the intermediate connecting section) was 
taken out of the heating furnace. After cooling, 245 kg of sponge titanium 
was taken out. 
OPERATION EXAMPLE 2 
Using the apparatus of Example 2, 243 kg of sponge titanium was obtained by 
the same operation as in Operation Example 2.