JPS62157642A - Manufacture of accumulation element for distributing and inserting mercury into discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing storage elements useful for dosing and introducing liquid mercury or liquid mercury alloys into discharge lamps.

BACKGROUND OF THE INVENTION Mercury is required for the operation of almost all discharge lamps. In high-pressure discharge lamps, mercury is introduced into the discharge vessel in the form of a halogen compound or by direct dripping by a pump piston.

In contrast, in low-pressure discharge lamps, in addition to direct dosing, glass or metal containers are used for metering and insertion, into which mercury or mercury alloys are filled. These containers are installed inside the discharge tube near the electrodes, and after sealing the discharge tube are injected with induced high frequency or ray→r
゛-It is opened using a ray of light, so that the mercury flows out. An example thereof is described in German Patent Application No. 3 [141 398].

Due to the high surface tension, it is practically impossible to meter liquid mercury accurately, especially in small quantities. Therefore, in most cases a much higher amount is inserted into the lamp than is necessary for operation. Therefore, when directly inserting liquid mercury, mercury droplets are also prevented from depositing in the pump piston.

This is the case when droplets typically have a certain minimum size.

Recently, in West German patent application no. 3534208.0,
Methods have also been proposed for cooling strands of liquid mercury below their freezing point. Next, a required length of strand, that is, a required amount of mercury, is separated from this frozen strand P and inserted into the discharge tube. This method allows extremely accurate dosing. However, this method is mechanically very complex and is only possible at great expense, since corresponding equipment must be integrated into the lamp production machine.

has a particularly high vapor pressure, the vapors being extremely harmful.

When mercury hits a hard surface, it scatters into tiny droplets that are very difficult to collect again.

Problem to be Solved by the Invention It is an object of the invention to provide a method for producing a storage element for dosing and inserting liquid mercury or liquid mercury alloys. Storage elements produced by this method allow precise dosing of mercury or mercury alloys,
It should be easy to load into the lamp. In this case, the physical properties of the mercury or mercury alloy must not change.

Means for achieving the invention The method for manufacturing such a storage element according to the invention comprises the following steps: a) mercury or a mercury alloy is added to one or more mercury or mercury alloys, each with a different metal salt solution and an anode of the corresponding metal; the metal is an element that does not itself form an alloy with mercury, is wettable by mercury and has a high oxidation resistance, and b) mercury or C) increase the respective metal content of the salt solution by electrolysis on the mercury alloy to produce one or several mercury-metal suspensions; C) in the case of several mercury-metal suspensions, identify these; d) Cover the resulting mercury-metal suspension product with anhydrous glycerin and heat treat at least 1[]0°C, and e) Decant the glycerin and wash and dry the suspended product. f) filtering the excess unadsorbed mercury or excess unadsorbed mercury alloy; g) filling the remaining filter cake into the bore of a steel cylinder and removing the excess mercury or excess mercury alloy from the piston; Squeeze under high pressure using h
) The brittle pressed body thus produced is pulverized and pressed bodies of corresponding dimensions are produced from the powder.

After the electrolysis carried out in step b), the metal content in the mercury metal suspension is between 0.5 and 1 part. The filtration carried out in step f) increases the metal content of the remaining filter cake by a factor of 5 to 8, and the subsequent squeezing increases it once more by a factor of 5 to 10. In this squeezing carried out in step g), the mercury content of the squeezing body can be varied to some extent by varying the squeezing force. The heat treatment carried out in step d) induces crystal growth, thereby causing step f
) is significantly improved. Furthermore, it is possible to decompose the mercury alloy produced by the metals involved in the mercury-metal suspension product, which is possible through heat treatment.
The metals may form mercury-free alloys with each other.

The pressed body produced by the method described above accumulates a precisely determinable amount of mercury or mercury alloy per unit weight of metal. Measurements have shown that pressed bodies from different batches, each produced under the same conditions, accumulate up to a maximum of approximately ±1
It was found that it fluctuated by 0%. In this way, the desired amount of mercury or mercury alloy is obtained depending on the weight of the pressed body. The squeeze body can be inserted into the discharge lamp in a very simple manner, with the squeeze body undergoing no accumulation losses either due to intermediate storage or due to contact. For long-term storage, this must of course be carried out under vacuum or protective gas. This is because mercury transpires into the normal atmosphere due to its high vapor pressure. It is therefore no longer necessary to overdosing mercury into the lamp.

Another advantage is that it is possible to fix the squeeze body in the pump piston, which eliminates the removal of the luminescent material as would be caused by dripping liquid mercury.

Then, when heating the electrode, the mercury is completely liberated from the squeeze body.

During the electrolysis carried out in step b), ammonium sulfate can additionally be added to the electrolytic vessel in order to increase the electrical conductivity. Possible anodic oxidation is largely suppressed by the addition of ethanol.

In order to obtain a content increase as uniform as possible, the mixture of mercury or mercury alloy and metal salt solution must be constantly stirred during the electrolysis.

The production of the mercury-metal suspension in the electrolytic vessel can be carried out periodically as well as continuously.

In the case of continuous electrolysis, a certain amount of the mercury-metal suspension that has already formed each time is discharged downwards and a corresponding amount of pure liquid mercury is replenished from above.

Theoretically, the metals of the metal salt solution and of the corresponding anode, which in addition to the mercury should each have a very large proportion of mercury-metal suspension products, can be selected from the periods of the periodic system (V a to V [ All elements of the [group] are suitable, but in practice only those metals are suitable which are non-toxic and/or radioactive and which allow the production of the pressed bodies as cheaply as possible. The use of metals such as iron and nickel has proven particularly useful, in which case a second metal such as copper is required to achieve sufficient oxidation resistance.Metal salts The use of metallic iron, chromium, and optionally nickel in the solution and anode also yields compressed bodies with good accumulation properties.

If the production of the compressed body and the insertion of the compressed body into the discharge vessel are carried out under protective gas, it is not necessary that the metal salt solution and the metal of the anode, alone or as a mixture or alloy, have a high oxidation resistance. Experiments on pressed bodies made of iron without the addition of metals to inhibit oxidation have shown that this pressed body, when stored in air (with evaporation of the mercury), forms mercury droplets over time. Ta. This is because as the oxidation progresses, the wettability of the pressed body deteriorates.

Particularly good results with respect to mercury accumulation, oxidation resistance and complete release of mercury when heated in the discharge tube are due to the fact that during its production the metal content of the mercury-metal suspension product is between 75 and 9 iron.
9.5% by weight and the remaining 100% by weight of copper is 25-0.5% by weight. Mercury-metal suspension products with a metal content of 55-80% by weight of nickel and 45-20% by weight of copper also accumulate mercury or mercury alloys very well and give pressed bodies with high oxidation resistance. but,
This pressed body firmly holds about half of the mercury at room temperature,
It has the disadvantage that it is liberated again only above 80-100°C. In the case of pressed bodies consisting of iron, chromium and nickel, the metal content of the mercury-metal suspension product ranges from iron 65 to
It should consist of 75% by weight chromium, 12-25% by weight chromium, and the remaining 100% by weight nickel 23-0%. but,
Such pressed bodies do not have high oxidation resistance like the above-mentioned pressed body compositions.

EXAMPLES Next, the present invention will be described in detail with reference to the accompanying drawings, with reference to an example of the production of a storage element by the method of the present invention.

The electrolytic vessel 1 for producing mercury-metal suspensions, shown in FIG. 1, consists of a double-walled glass vessel 2, through which cooling water flows through an inlet 3 and an outlet 4. . As an anode, a metal cylinder 5 is used, which is connected by a cable 6 to the anode of a direct current power source (not shown).

The metal cylinder 5 has a central hole 7 through which a stirrer 8 made of glass extends. The cathode formed by the mercury 9 located below in the container is connected by a copper wire 10 to the cathode of the power supply. Above the mercury cathode there is an electrolyte 11 in the form of a metal salt solution, the salt solution and the metal of the anode in each case matching. By applying a direct voltage, the mercury increases the metal content of the electrolyte 11, the stirrer 8 ensuring the highest possible homogeneity in its movement. The generated mercury/metal suspension is sent to cock 12.
can be discharged downward.

In FIG. 2, a steel cylinder 13 for pressing the filter cake 14 is shown. The steel cylinder consists of a cylindrical part 15 having a circular central hole 16 with a diameter of 15 mm;
A filter cake 14 is present therein, into which a piston 17 is inserted from above. A hardened steel plate 18 is screwed onto the polished end surface of the cylindrical portion 15. A force of 7 x 10'' Pat is applied to the piston 17 to squeeze out the excess mercury total filtration cake 14.

The mercury escapes through the gap between the cylindrical portion 15 and the steel plate 18 and exits the steel cylinder 13 at the point indicated by arrows 19.20.

Example for the production of pressed bodies of iron and copper: 1500 I of mercury is placed in an electrolytic vessel with an iron anode and an electrolytic vessel with a copper anode, respectively, as illustrated in FIG. 200ml of electrolyte for mercury/iron electrolysis is FeSO46f
i, 13 ml of concentrated sulfuric acid and (NH,)2 as an additive
Consisting of S0.10.9 and methanol 1Qmi. 2
If a DC voltage of 20 V is applied at the current of the OA, a mercury-iron suspension with an iron content of about 0.5 weight fL% is obtained after an electrolysis time of 20 minutes with constant stirring.

Similarly, 200 ml of electrolyte solution for mercury/copper electrolysis is C
Contains uSO420 & N until clearly dissolved in it
Add H3. At a voltage of 10 cm and a current of 40 A, a mercury-copper suspension with a copper content of approximately 1 H is obtained after an electrolysis time of 20 minutes with constant stirring. Both mercury-metal suspensions are mixed such that the metal content consists of 95% by weight of iron and 5% by weight of copper in addition to mercury.

The mercury-metal suspension product thus formed is covered with anhydrous glycerin and heat treated at 2400C for 1 hour. After decanting the glycerin, the suspended product is washed and dried. By subsequently filtering out the excess mercury using a porous G6 glass frit, the metal content is increased tenfold.

The remaining filter cake is packed into the steel cylinder shown in Figure 2 and high pressure (see below) is applied to the piston to squeeze out the remaining excess mercury. The pressed body made in this way was crushed using an eccentric press to a diameter of 1.5mm and a height of about 0.4mm.
A disk-shaped pressed body is manufactured. Depending on the squeezing force of the filter cake in the steel cylinder, the following weight proportions of mercury in the squeezing body are obtained: 74% by weight at 5.7 x 107 Pa;
66% by weight at 11.3X107Pa, 22.6X1
63% by weight for Q7Pa and 60% by weight for 56.6 x 107P&.

[Brief explanation of drawings]

The attached drawings show an example of manufacturing a storage element by the method of the present invention, and Figure 1 shows mercury/metal W! FIG. 2 is a cross-sectional view showing the structure of an electrolytic vessel for producing turbidity A, and FIG. 2 is a cross-sectional view of a steel cylinder for squeezing out the filter cake. 1... Electrolytic container, 2... Double-walled glass container, 3...
・Inflow port, 4...Outflow port, 5...Metal cylinder, 6
... Cable, 7... Center hole, 8... Stirrer,
9...Mercury, 10...Copper wire, 11...Electrolyte, 1
2... Cock, 13... Steel cylinder, 14... Filter cake, 15... Cylindrical part, 16... Center hole,
17... Gistone, 18... Steel plate, 19.20...
・Arrow 0 1... Electrolytic container

Claims (1)

[Claims] 1. A method for producing a storage element used for dispensing and inserting liquid mercury or a liquid mercury alloy into a discharge lamp, comprising the following steps: a) mercury or mercury alloy is mixed with a different metal; into one or several electrolytic vessels with a salt solution and an anode (5) of the corresponding metal, the metal being not itself alloyed with mercury, alone or in a mixture or as an alloy, but being an element that is wettable and has high oxidation resistance; b) mercury or mercury alloys are electrolyzed to increase the metal content of the salt solution to form one or several mercury-metal suspensions; c) ) in the case of some mercury-metal suspensions, mixing them in specific proportions; d) covering the resulting mercury-metal suspension product with anhydrous glycerin and heat-treating it at a temperature of at least 100°C; e) adding the glycerin to the mixture; decanting, washing and drying the suspended product; f) filtering off excess unadsorbed mercury or excess unadsorbed mercury alloy; g) pouring the remaining filter cake into the bore of the steel cylinder (13). and squeezing out excess mercury or excess mercury alloy under high pressure using a piston (17); h) pulverizing the brittle pressed body thus produced and producing pressed bodies of corresponding dimensions from the powder; A method for producing a storage element for metering and inserting mercury into a discharge lamp, characterized in that: 2. The method according to claim 1, wherein ammonium sulfate is additionally added to the electrolytic vessel to increase the conductivity. 3. The method according to claim 1, wherein ethanol is additionally added to the electrolytic vessel to prevent anodic oxidation. 4. In order to uniformly increase the metal content of mercury or mercury alloy in electrolytic vessel (1), the mixture consisting of mercury or mercury alloy and metal salt solution is constantly moved with a stirrer (8). The method described in Scope 1. 5. For continuous electrolysis in the container (1), a certain amount of the mercury-metal suspension already formed each time is discharged downwards;
2. A method as claimed in claim 1, in which a corresponding amount of pure liquid mercury is added from above. 6. In addition to mercury, the metal salt solution and the metal of the corresponding anode, which in each case contain large amounts of mercury-metal suspension products, are elements of groups IVa to VIII of the Periodic Law. The method described in Section 1. 7. The metals of the metal salt solution and the anode are iron and copper;
A method according to claims 1 and 6. 8. The method according to claims 1 and 6, wherein the metals of the metal salt solution and the anode are nickel and copper. 9. The method according to claims 1 and 6, wherein the metal of the metal salt solution and the anode is iron, chromium and optionally nickel. 10. The metal content in the mercury/metal suspension product is 75-99.5% by weight of iron and the remaining 100% is copper 25-0.
．． Claims 1 and 7 consisting of 5% by weight.
The method described in section. 11. The method according to claims 1 and 8, wherein the metal content in the mercury-metal suspension product consists of 55-80% by weight of nickel and the remaining 100% of 45-20% by weight of copper. 12. The content of the metals in the mercury-metal suspension product consists of 65-75% by weight of iron, 12-25% by weight of chromium and the remaining 100% 23-0% by weight of nickel; and The method described in paragraph 9.