DE2135873B2 - Cell top for amalgam high-load cells - Google Patents

Description

serves as cell cover, anode carrier, electrical supply and anode at the same time. Since such cells are supplied with the saline solution under high pressure, the prevailing hydraulic pressure makes the formation of gas bubbles very difficult in such cells. This increase d ·. Nucleation energy of the gas bubbles is reflected in a higher specific energy consumption. In addition, in such electrolysis cells, the electrolyte fills the interior space of the cell, so that the electrolyte is necessarily heavily permeated by the anodically formed chlorine gas bubbles. An electrolyte enriched with chlorine gas bubbles has a much higher specific electrical resistance, which results in a further increase in the specific energy consumption when operating such cells. Due to these disadvantages, which result in a high specific energy consumption per ton of chlorine that would be generated in such cells, and the additional costs for the necessary pumping systems, it was not possible to carry out an economical electrolysis operation with these cells.

The present invention is based on the object of a cell top part equipped with metal anodes with conventional brine speeds and pressures at which

1. the power supply and distribution from i: books Conductor material (aluminum or copper) in the form of side members with a large cross-section reaches up to the actual anode, around the resistance-increasing constriction of the To avoid current paths,

2. the amount of titanium is limited to a minimum,

3. the actual anode is easy to replace,

4. the adjustment of the individual anode during assembly is not necessary,

5. the distance between the mercury cathode and the actual anode is very small and very small is precisely adjustable in order to keep the voltage drop in the electrolyte very small, and

(S. the overall structure is durable and uncomplicated and all other requirements of an economic Full load operation.

These objects are achieved in a particularly advantageous manner by the cell top according to the invention.

This cell upper part with automatically adjustable support structure consists of shielded cells Power supply lines and distributors made of copper or aluminum conductor material in the form of Longitudinal beams, underlying contact blocks made of valve metal, a cell shield welded to them made of valve metal sheet and easily exchangeable anode rods attached to the contact strips made of coated valve metal. In some embodiments with anode grids, it can be It has proven expedient to use short contact pins made of the same instead of the contact blocks made of valve metal Material to use.

Some embodiments of the present invention are described below with reference to the drawings described for example, where the reference number (3) in each case the U-shaped profiled Ventilme- (allblech represents.

Fig. I shows in section an amalgam high-load cell in a perspective view, equipped with the Cell imber part according to the invention;

Fig. 2 shows the attachment of the contact strip (2) to the side member (ij by means of expansion screws;

3 shows the fastening of the contact strip (2) to the U-shaped longitudinal member (1) by means of screws;

F'g. 4 shows the attachment of the contact strip (2) to the angular longitudinal member (1) by means of Screws;

Fig. 5 shows the attachment of the contact strip (2) with the longitudinal beam (1) from below with corrosion-resistant Screws and seals, a contacting means (5) also being used;

6 shows the attachment of the contact strip (2) to the longitudinal beam (1) by means of a press fit; Fig. 7 shows the connection between the side members

(1) and contact strip (2) with an enlarged contact area, the contact being made by a low-melting point Alloy is improved;

Fig. 8 shows the connection between contact strips

(2) and anode rods (4) by means of clamping screws (8), with an additional contacting means (7) is used;

Fig. 9 shows the fastening of individual with tenons

(9) provided anode rods (4) on the contact strips (2) by means of a press fit;

Fig. 10 shows the attachment of individual anode bars (4) to the contact strips (2) by means of grooved pins

(10) represents;

Fig. 11 shows the attachment of individual anode bars (4) on the contact strips (2) by means of snap pins (11);

Fig. 12 shows the attachment of individual anode bars (4) on the edge of the contact strips (2) by means Snap pins (11);

Fig. 13 shows the attachment of individual anode bars (4) to the contact strips (2) by means of wedges (12) made of durable material;

14 shows the upside down cell top equipped with anode grids (13);

FIG. 15 shows another embodiment of an enlarged contact area as shown in FIG. 7; FIG.

Fig. I (S shows the attachment of the anode grids (13) on the contact bars (2) with countersunk screws;

17 shows the fastening of the anode grids (13) to the contact strips (2) by means of a press fit;

IX shows anode grids arranged in the longitudinal direction (13) which are welded to the contact strips (2);

Fig. I ° shows an anode grate (13) from parallel arranged webs (14) which open at their ends into a frame (15) which is attached to the Kontaktlcisten (2) is attached;

Fig. 20 shows an anode grate (13), from parallel arranged webs (14), which by transverse strips (16) are interrupted to the contact lists (2) be attached;

21 shows a section of an anode grate (13), which is a slotted sheet metal;

22 shows a section of an anode grate (13) which is a slotted sheet metal. where the webs (14) form an angle of 90 ° with the cathode;

Fig. 23 shows a section of an anode grate (13), in which the openings between the webs (14) are manufactured without material losses;

24 shows a section of an anode grate (13), which is a perforated sheet metal, the holes are called are made without loss of material;

25 and 26 show a detail of an anode grate (13) in which the webs (14) and transverse strips (16) consist of valve metal semi-finished products and are welded to one another;

Fig. 27 shows a section through an embodiment in which the anode rods (4) parallel to Mercury flow direction are arranged, the anode rods (4) additionally arranged across a Auxiliary bridge (17) are contacted;

28 shows an embodiment of the cell top part according to the invention with contact bolts (2a);

29 shows an anode grate (13) with transverse strips (16), in which the gas vent holes run parallel to the mercury overflow direction.

The items indicated in the figures explained above refer to the following components:
Pos. 1 = longitudinal beam made of aluminum or copper conductor material

Pos. 2 = contact strip made of valve metal
Pos. La = contact pin made of valve metal
Pos. 3 = cell shield made of U-shaped profiled valve metal sheet

Pos. 4 = anode rods made of coated valve metal

Pos. 5 = oxidation-inhibiting contact

medium or contact-improving metal

Pos. 6 = low-melting alloy, e.g. B. Lot,

Lipowitz alloy, Wood metal
Pos. 7 = contact means such as coating made of platinum metal, silver, antioxidant paste

Pos. 8 = clamping screws

Pos. 9 = pins attached to the anode bars. Pos. 10 = grooved pins attached to the anode bars

Pos. 11 = detonating pins attached to the anode rods

Item 12 = wedges made of resistant material
Item 13 = easily replaceable anode grids off

coated valve metal
Item 14 = bars of the anode grids
Pos. 15 = frame of the anode grids
Pos. 16 = horizontal stripes of the anode grids
Pos. 17 = auxiliary bridge

In Fig. 1, the cell top according to the invention is with automatically adjustable support structure that from the inside of the cell shielded current leads and distributors made of copper or aluminum conductor material in the form of longitudinal members (1), underlying contact strips (2) made of valve metal, one welded to it cell shield (3) made of U-shaped profiled valve metal sheet and to the Contact strips (2) attached, easily exchangeable anode rods (4) made of coated valve metal shown schematically. The cell top according to the invention allows the very good electrical Conductive materials aluminum or copper made longitudinal member (1) at a short distance from the To arrange anode rods (4) and thus the supply of the amount of electricity required for electrolysis to allow minimal voltage drop. The very thin ones, made as valve metal, preferably titanium Contact strips (2) do not constrict the current paths and lead to considerable titanium savings, without increasing the electrical resistance. 2 to 4 are three embodiments the side members made of conductor material (1)

shown, the screwing with the contact strips (2) enable from above. Another possibility is to open the contact strips (2) from below to screw on the side members (1) (Fig. 5). Since the screws in this embodiment with the Electrolytes are in constant contact, they must be made of corrosion-resistant material, preferably Valve metal, exist and additionally be sealed. Another connection option between Longitudinal support (1) and contact strip (2) can be made by means of a press fit, as shown in FIG.

A reduction in the contact resistance results from an enlarged contact area between Contact strip (2) and longitudinal member (1). This increase in the contact area can be achieved by a A favorable design of the surfaces, as represented by a toothing (FIG. 16), can be achieved. The same Wavy or lamellar shaped contact surfaces also have an effect. In the one shown in FIG Embodiment is the enlargement of the contact area through a suitable design of the screw connection achieved.

In order to prevent oxidation of the valve metal contact surface during long operating times, it is in In some cases, the contact area between the longitudinal member (1) and the contact strip (2) is appropriate precious metals and / or an antioxidant paste.

Mainly in the case of the embodiments with an enlarged contact area, one obtains an additional one Contacting the side members (1) with the contact strips (2) via a low-melting alloy (6) e.g. B. Lot, a further decrease in the contact resistance. The melting point of this Alloy can also be below the operating temperature of the electrolytic cell to ensure uniformity To ensure filling of the cavities.

8 to 13 are different embodiments of the connection between the contact strip (2) and anode rods (4) are shown. Fig. 8 shows the attachment of the anode rods (4) in the prefabricated for this purpose Recesses in the contact strip (2) with the help of clamping screws (8). Other embodiments consist in that pins (Fig. 9 Pos. 9) or grooved pins (Fig. H), Pos. 10) of the anode rods (4) are pressed into bores in the contact strip (2). A very simple attachment can via snap pins (Fig. 11 and 12, item 11) Hollow pegs are attached to the anode rods (4), the cavity of which is provided with an explosive charge During assembly, these snap pins are inserted into holes provided in the contact strip (2). Depending on the height of the holes in the contact strips (2), the detonation pin is attached! either mainly via a press fit (as shown in FIG. 11) or via a hollow rivet-like Connection (Fig. 12). As shown in Fig. 12 on the Ausfüh approximate form with snap pins (11), can also the connection shown in FIGS. 9 and 10 fertilize on the edge of the contact strip (2). The fastening of the anode rods can also be done with keiler (12) made of resistant materials such as valve metal or plastic (Fig. 13).

The valve metal surfaces that come into contact with the cell medium passivate with anodi Shem use with the formation of non-conductive oxide layers. Contact areas where there is a contact with the cell medium cannot be completely ruled out

Ben is going to have to go through additional contact means to be protected. As an additional contacting agent act as layers of platinum metal, silver, antioxidant paste, etc. These contacting agents are shown in Figure 8 by position 7 when using clamping screws; she but can also be used with the other types of fastening.

The anode rods (4) of the cell top according to the invention consist of valve metal that is provided with coatings that provide an economical Enable the anode process to be carried out. The term "anode rods" is not limited only on rods with a circular cross-section, but any cross-section, e.g. B. square, Triangle, hexagon, rectangle, etc. can be used.

If the anode rods (4) are to be arranged parallel to the direction of mercury flow, an additional one is required Contact is possible via a transversely arranged auxiliary bridge (Fig. 27. Item 17).

14 shows a further embodiment of the cell top part according to the invention with automatic adjustable support structure, which consists of current leads and distributors shielded from the inside of the cell Made of copper or aluminum conductor material in the form of side members (1), contact strips underneath (2) made of valve metal, a welded cell shield (3) made of valve metal sheet and on the contact strips (2) attached, easily exchangeable anode grids (13) made of coated valve metal exists, shown. The connection between the side member (1) and the contact strip (2) is expedient performed in a manner as described in the first embodiment.

The anode grids (13) can be attached to the contact strips (2) by means of a screw connection (Fig. 16), with the contact area between Contact strip (2) and anode grate (13) is additionally coated with platinum metal. The previously mentioned types of fastening come as further embodiments by means of pins (Fig. 17), grooved pins, snap pins and wedges. In the embodiments with anode grids, far fewer connecting elements can be used between contact strips (2) and anode grids (13) can be used than in the embodiments with anode bars. Around Nevertheless, a safe and economical supply of electricity to the anode grates during operation to ensure, the contact surfaces with one of the already mentioned contacting means Mistake. Another safe supply of electricity to the anode grids is through a metallic connection between anode grate and cor. A Welded connection (Fig. 8). Since there are only a few connection points here, the Anode grids can be replaced by removing the welded joint using a suitable tool, z. B. cut-off saw solves. In order to edit the contact strips (2) when replacing them avoid, the webs (14) of the new anode grids are welded offset to the contact strip. That's why for this purpose, anode grids are manufactured with the transverse strips (16) spaced at different distances. Then only will After replacing it several times, reworking of the contact strip is necessary.

Some embodiments of the anode grids are shown in Fig. I ¹ J to 26. FIG. 19 shows an embodiment of an anode grate made of webs (14) arranged in parallel with a frame (15), while in FIG. 20 an embodiment with transverse strips (16) is shown. The anode grids (13) are fastened to the contact strips (2) by means of one of the connections described above on the frame (15) or on the transverse strips (16). If expanded metal is used as the anode grate, the mechanical strength is obtained by welding it to a frame (IS) or corresponding transverse strips (16) made of semi-finished valve metal. Anode grids, which are made in one piece, are shown in FIGS. 19 to 24. If the anode grids are made from valve metal sheets, the openings can be made with (see FIGS. 19 to 22) or without loss of material (see FIGS. 23 and 24). 19 to 21 show anode grids made from slotted valve metal sheets. By rotating the webs, with the same anode area, significantly larger openings are obtained, which lead to the chlorine gas bubbles being diverted from the electrode area as quickly as possible. It has been shown that the webs should expediently form angles of 30 to 90 ° with the cathode. An embodiment in which the angle is 90 ° is shown in FIG. In Fig. 23 a further embodiment is shown with a cross bar (16). In this embodiment, the openings are produced by bending over the web edges without any loss of material. The shape of an anode grate shown in FIG. 24 can also be produced without loss of material by e.g. B. by means of a pointed tool punches holes in a valve metal sheet without deburring the holes afterwards. Of course, instead of this plate, a commercially available perforated plate can be used, which is provided with transverse strips to achieve mechanical strength.

Anode grids (13) are shown in FIGS. 25 and 26, their webs (14) and transverse strips (16) made of valve metal semifinished products exist that are welded together. Anode grids can also be used in the same way (13), the webs (14) and frame (15) of which consist of welded valve metal semi-finished products.

All anode grids described above can either only be on one side or on both Sides can be provided with a coating that allows the anode process to be carried out economically enables.

In a further embodiment, the webs the anode grids consist entirely or at least on their surface of sintered, activated valve metal and be welded to the frame or transverse strip.

Fig. 28 shows a third embodiment of the invention Cell top for amalgam high-load cells with shielded from the inside of the cell Current leads and distributors made of copper or aluminum conductor material in the form of side members (1), underlying contact pin (2a) made of valve metal, a cell shield welded to it (3) Made of valve sheet metal and attached to the contact pin (2a), easily replaceable Anode grids (13) made of coated valve metal. The connection between the side member (1) and the contact bolt (2a) or contact pin (2a) and connection

Floor grating (13) is expediently carried out in the same way as in the previous embodiments. This embodiment with contact bolts (la) leads to a further saving of valve metal and thus to a reduction in production costs. Due to the large conductor cross-section of the short contact pins (2a), the increase in the cell voltage due to the unavoidable constriction of the current paths is insignificant in this embodiment. The anode grids (13) are designed in the same way as in the second embodiment described above.

In the two embodiments of the cell top according to the invention with anode grids

(13) the webs (14) of the anode grids (13) can be arranged transversely or parallel to the direction of mercury flow will. The arrangement and design of anode grids with frames in which the webs are parallel to the direction of mercury flow is shown in FIG. 14 evident. The design of anode grids in which the webs run transversely to the direction of mercury flow, is in Fig. 19 on an anode grate with frame (15) and in Figs. 16 and 20 on an anode grate shown with horizontal stripes (16). 29 shows an anode grate (13) with transverse strips (16), the webs of which

(14) are arranged parallel to the direction of mercury flow.

In the cell top part according to the invention, the power supply and distribution is from the very good conductive Materials made of copper or aluminum, which saves a lot of titanium. By the use of the much cheaper and better conductive conductor materials is socially acceptable, the power supply lines and distributors should be generously dimensioned. The ample dimensioning of the Conductor cross-section and the short distances to the actual anode is achieved with this cell top an excellent stress coefficient is achieved. The better the stress coefficient, the lower the operating costs.

In all embodiments of the cell top part according to the invention, is determined by the construction an excellent plane parallelism of the anode surfaces is achieved. Due to the plane parallelism, there is a very small distance between the mercury cathode and anode possible, resulting in a very small voltage drop results in the electrolyte. This plane parallelism of the anode surface remains even when the Anode rods or anode grates are retained because of the design when installing the replacement anodes Place the connecting pieces on them in the recesses provided for this purpose in the contact strip or the contact bolts intervene and thus result in an automatic adjustment of the anode surface. The elaborate one and the lengthy adjustment process involved in the conventional assembly of metal anodes is no longer necessary thus when using the cell top according to the invention. Despite this time-consuming adjustment it is very difficult with the conventional stamp anodes during the entire service life of the To maintain plane parallelism. However, plane parallelism of the anode surface is one of the most important requirements for safe operation of the amalgam cells, because unevenness in the anode surface is a frequent cause of short circuits are.

The anode rods and anode grids of the cell top according to the invention are on all sides from Electrolyte washes around and therefore the electrolysis process can take place on the entire coated surface the anodes take place. As a result, the production capacity is increased while the space requirement remains the same possible.

The construction of the cell top according to the invention allows the anode rods or anode grates to be designed in such a way that the chlorine gas evolved is discharged from the electrode area as quickly as possible. This largely prevents the undesired influence of the so-called gas bubble effect.

By largely replacing the valve metal previously required for power supply and distribution The much cheaper conductor materials copper or aluminum result in drastic titanium savings and thus a considerable reduction in investment costs.

A source of interference in previous cell construction are the numerous seals required in the cell cover, which have to be constantly maintained and checked. In the construction according to the invention such or similar wear parts are not required. Thus, the overall structure of the invention Cell upper part for amalgam high load cells durable and uncomplicated and therefore corresponds to all Requirements of an economical high-load operation.

In addition 9 sheets of drawings

Claims (1)

Patent claims: 1. Cell upper part for amalgam high-load cells with automatically adjustable support structure, in which parallel, rectangular longitudinal beams (1) made of copper or aluminum conductor material are arranged at a distance from one another, the underside of the carrier being interchangeable with contact strips (2) or bolts (2a) made of valve metal Anodes (4, 13) made of coated valve metal are electrically connected, characterized in that between each pair of juxtaposed supports (1) a U-shaped profiled valve metal sheet (3) with downwardly directed flanges, which are connected to the strips (2) or the bolts ( 2a) are welded, is arranged in such a way that the carrier and the strips or bolts underneath form a tight cover together with the profiled sheets. 2. Cell upper part according to claim 1, characterized in that that the contact strips (2) or bolts (2a) are screwed to the side members (1) or are attached by means of a press fit. 3. Cell upper part according to claim 1 and 2, characterized in that the in Contacting surfaces of the side members (1) and the contact strips (2) or pins (2 «) are toothed or wavy. 4. cell top according to claim 1 to 3, characterized in that the contact strips (2) or bolts (2a) are coated on the carrier side with contact materials (5). 5. cell top according to claim 1 to 3, characterized in that between the longitudinal members (1) and contact strips (2) or bolts (2a) a Alloy with a low melting point is appropriate. ft. cell top according to claims 1 to 5, characterized in that the contact strips (2) have recesses on the anode side and the anodes (4) are formed from parallel rods, which are pressed into the recesses by means of clamping screws (8). 7. cell top according to claim 1 to 5, characterized in that the anodes (4, 13) Have pins (9), grooved pins (10) or snap pins (11), by means of which the anodes (4, 13) in Anode-side recesses of the contact strips (2) or bolts (2a) are pressed in. 8. cell top according to claim 1 to S, characterized in that the anodes (4, 13) by wedges (12) made of durable material, such as valve metal, plastic, in recesses of the Contact strips (2) or bolts (2a) are attached. 9. cell top according to claim I to 8, characterized in that between the contact strips (2) or bolts (2a) and the anodes (4, 13) a contacting means (7), namely a coating of a platinum metal, silver or an antioxidant paste attached is. The quantities of chlorine gas developed in the high-current loaded chlor-alkali electrolysis cells at the anode must be removed from the electrode area as quickly as possible for energy reasons. It is known that if the chlorine gas bubbles linger in the electrode area, the cell voltage increases significantly and the current yield decreases. This phenomenon, known under the collective term "gas bubble effect", has led to changes in the design of the graphite anodes in recent years. For example, the anode plates were provided with numerous slots and gas outlet holes, which has actually brought the desired success _{up to current densities D 1} = 10 kA / m ^2. The ceramic-like graphite anode gradually stands in the way of a further increase in the current density. In the case of very high current densities, D _A greater than H) kA / m ² , it becomes difficult to get the evolved chlorine gas away quickly enough from the underside of the horizontal anode plate, which is itself amply slit and provided with a large number of gas drainage holes. The result is higher overvoltage on the graphite and greater voltage losses in the electrolyte enriched with chlorine gas bubbles. In addition, the greater the number of slots and gas vent holes, the greater the internal resistance, the loss of graphite and the sensitivity of the anodes to transport. Attempts are made to circumvent this limitation by using coated titanium anodes. Using the cell top, which is matched to the stem-shaped graphite anode, expensive titanium anodes are used which, however, do not fully take into account the possibilities of this new, activated electrode material. Since the current supply and distribution of the anode is arranged inside the cell and must therefore also consist of the resistant titanium (DE-OS 2031525, US-PS 3308043 and FR-PS 2060810), large amounts of this expensive material are required, which was previously the case inhibits the widespread use of this anode. In addition, the retention of the old cell superstructure and the stem-shaped anode shape harbors the disadvantages inherent in these constructions. With its numerous, sometimes very short-lived individual parts, such as rubberized cell covers, bus bars, flexible power distribution cables, anode holding rods, protective tubes, sealing elements, screw and / or soldered contacts, anode suspensions and the actual anodes, the cell superstructure has remained extremely complex and complex. Long, resistance-increasing current paths, numerous voltage-costing contacts and anode holding rods which make the power supply and current distribution more difficult, in which the current paths are very sensitively constricted, hardly allow the voltage coefficient (A value) of the electrolysis cell to drop below 0.12. Because of the large dimensional tolerances that have hitherto been customary in cell construction, when titanium anodes are used in these cells, a complex, lengthy and labor-intensive adjustment process must always be carried out when assembling the metal anodes. Even the replacement of the single / elode adjustment with motorized group adjustment did not help. From DE-AS I 417 193 an electrolysis cell is known that works with high brine speed and high pressure and one with a noble metal Has platinum group coated titanium component that