FI59269B - BELAGD TITANANOD FOER KVICKSILVERHOEGBELASTNINGSCELLER FOER KLORALKALIELEKTROLYSER - Google Patents

Description

S '"- [B] (11) ADVERTISING | λλ, λ UM (11) UTLÄGGNI NGSSKRIFT $? £ O y, c (45) 10 07 nJ1 * / (51) Ky.lk?/lnt.a. 3 (J 25 B 11/02 FINLAND I —Fl N LAND (21) P «t * nttlh« k * mti * - Ptt * nt »iw6knln * 1 ^ 36/71 + (22) Htkamliptlvl - AittSknlnftdtg 10.05.7 ^

^ ^ (23) Atkuptlvt — GIW | h «tid« | 10.05.7U

(41) Tulhit JulklMluI - Bllvit off «ntll | 11.11.7! + P> UMtkj. r «klst« riKallitut (4- |. kwl] .IUta, p, „. -

Patent · och raglttaratyralaan 'Amökan utl «fd oeh utl.skrlfun public« r * d 31.03.81 * (32) (33) (31) Pyy4 «* y priorittt 10.05.73

Federal Republic of Germany-Förbundsrepubliken Tyskland (DE) P 2323 ^ 97 * 1 Proven-Styrkt (71) Conradty GmbH & Co. KG Metallelektroden KG, Griinthal, D-8505 Röthen- Bach a.d. Pegnitz, Federal Republic of Germany Förbundsrepubliken Tyskland (DE) (72) Konrad Koziol, Röthenbach a.d. Pegnitz, Karl-Heinz Sieberer, Zirndorf / b. Niirnberg, Baptist Zenk, Röthenbach a.d. Pegnitz, Federal Republic of Germany Förbundsrepubliken Tyskland (DE) (71 *) Oy Kolster Ab (5 ^) Coated titanium anode for high-power mercury cells for chlor-alkali electrolysis - Belagd titananod för kvicksilverhögbelast-ningsceller för kloral

The invention relates to a coated titanium anode for high-power mercury cells used in chlor-alkali electrolysis, for use in particular when the anode current densities (D.) are oral. . 2 Λ than those of a 10 kA / m, wherein the anode has a number of metal tracks, which are arranged parallel to each other and which are fixedly connected to one or more of the common lead, and coated with an activating agent in the area in which the actual surface (each of the metal strip coated with the long sides, bottom and end faces of the sum of ) at least half is arranged perpendicular to the main surface of the anode.

A similar anode is known from British Patent Publication 1,076,973. The known electrode consists, for example, of vertically arranged titanium strips having dimensions of 400 x 10 x 1 mm. The height of the area coated with the activating agent of each titanium strip is less than half the total height of each strip. The spacing of adjacent titanium strips is 3 mm and allows easy removal of the chlorine formed. The known 2,526,292 electrode is apparently intended for an anode current density (D 2) of about 2 to 10 kA / m.

In contrast, it is an object of the present invention to further develop the known titanium anode so as to allow higher anode current densities (D 2) and further guarantee the removal of chlorine bubbles, low internal resistance and a long service life of the structure and coating, even under high current load.

Based on a titanium anode having the above-mentioned characteristics, the solution to this problem is characterized in that the coated area, measured from below the anode, is higher than 5 mm but not higher than 20 mm, and that its true surface is 7.5, 10 and 15 mm up to heights exceeds the projected anode surface (anode length x width) by at least 3 1/3, k- resp.

H 3 / u-fold.

The invention will now be described on the basis of preferred embodiments and with reference to the drawings.

Figure 1 shows an anode with coated, vertically arranged titanium strips 1 mm thick and 20 mm high. The distance 1 between adjacent titanium strips is 2 nm. the flours 1 are connected to each other at the top by a few transverse welding seams 2. The power distribution is provided by a welded, uncoated titanium cross-member 3 provided with a titanium shield tube 4 for the power cable.

The parameters used to describe the invention, such as the true surface, the projected anode surface and the height of the coated area, will be described in connection with the electrodes of Figure 1.

The width of the anode (b) corresponds to the length of each titanium strip, e.g. 400 mm;

The length of the anode (1) consists of the number of titanium strips and the distance between adjacent titanium strips, the length of the anode (1) can be e.g. 399 mm.

The product of the anode width (b) and the anode length (1) results in a projected anode surface (A ^), i.e.

Ap = a x b = 159,600 m2

The actual surface (A 2) of the coated area of each titanium strip corresponds to the sum of: the coated underside of the titanium strip plus the coated long sides plus the coated end surfaces; with a strip width (c) of 1 mm and a distance of adjacent strips of 2 mm (s),:

1 _ 399 * 4GC

undersides of the tape A ^ "c + s · c · d - 3, _ Λ 2-1. y, 798 · 400 · h long sides of the tape A2 = * b · h = - = j-- ...... · ^ A 2-1. V 798 · h end ends of the tape A ^ = * ch = - ^ - The true surface (A ^) depending on the height (h) is obtained as follows: A. = A, + A_ + A0.

1 1 2 3 For the different heights (h) of the coated area 5, 7 1/2, 10, 15 and 20 mm, the resulting relationships between the actual surface (A ^) and the projected anode surface (A) are obtained.

P

Coating height (h) mm Ratio A ^: A ^ 5 3.67: 1 7.5 5.33: 1 10 7: 1 15 10.33: 1 2 0 14: 1 In this embodiment, more than 95% of the actual surface is fitted to the anode perpendicular to the main surface.

Figure 2 shows a titanium anode with a projected anode surface of 400 x 400 mm, the metal strips of which protrude on both sides of the massive central body like comb spikes. The metal strips 1 are made of a coated, 12 mm thick titanium plate and the width of the strips is 2.5 mm; the distance between adjacent metal strips is 2.5 mm. The central body, not shown in the section, also serves as a power distribution, it is 60 mm wide and has grooves 2.5 mm wide and 2.5 mm deep below, in the middle of the recessed body there is a screw contact for a copper power supply cable from which only the titanium shield 4 is visible.

„59269 At a pavement height of 7.5 resp. 10 mm, the ratio between the actual surface and the projected anode surface is 3.52: 1 resp. * +, Δ 3: 1; about 80% of the true surface coated with the activating agent is arranged vertically with respect to the main plane of the anode.

Fig. 3 shows an anode similar to Fig. 1, in which the vertically oriented titanium strips are in each case arranged at 2 mm intervals. The 7.5 mm high and 2 mm thick titanium strips are welded to the holding ribs 2, which are partially connected to the contact box in the center of the anode by means of titanium rods 9 with a larger cross-section. A titanium protection tube M is further connected to the central contact box. The resulting star-shaped current distribution ensures an even load on the anode surface. When the height of the coating layer is 5 ...

7.5 mm, the ratio of the active true surface of this anode to the projected anode surface is 3.01 ... 4.75: 1.

The titanium anode shown in Fig. 4, with 20 mm high, 1.5 mm thick, 2.5 mm spaced titanium strips 1, comprises a central titanium box 7 with current distribution discs 8 made of titanium-plated copper, to which the strips 1 are welded. The central titanium box 7 is led by a power supply rod 5 made of copper, which in turn is protected by a titanium sleeve 4. For safety reasons, the ratio of the height of the busbar to the height of the titanium strip is 0.75: 1. Using the same dimensions as in the anode of Fig. 1. 15 mm, true surface to projected anode surface ratio 5.39: 1 resp. 7.90: 1.

Fig. 5 shows a section of the anode according to Fig. 4, showing in detail the method of connecting the current supply rod 5 made of copper by means of a flange and a closed titanium threaded part 6 provided with a titanium protective tube to the central titanium box 7 of the anode. Parts 6 and 7 have a thread with a large ridge angle oC (oC = angle between the side of the extended thread and the perpendicular to the longitudinal axis of the thread, cf. also DT-PS 1 237 482). Thanks to this structure, the current distribution rail with the titanium strips of the anode emanating from it can be turned relative to the cathode only by unscrewing the power supply cable. This is very advantageous in view of short-circuit damage below the anode, as well as in connection with the longer service life of the anode during which the active coating in the vicinity of the cathode wears out, almost or completely. In such cases, the active coating of the less stressed upper regions may still, after turning the anode, take a long time to process the anode process, while conventional anodes must then be immediately recoated.

Based on its characteristics, the anode of the invention for the first time offers the possibility of extensive utilization of current control and a consequent reduction in the actual current densities, resulting in a corresponding reduction in cell voltage.

Figure 6 shows the dependence of the cell voltage on the anode current density for three types of the same substance

Me (I) g i-PtgO 2 for the activated titanium anode type (where Me (I) denotes an alkali metal, preferably Li or Na; cf. also German Publication No. 18 13 944), where curve I is obtained from strips with 1 mm thick and 10 mm high strips anodes with a 3 mm gap between the strips and a coating height of 2 mm and curves II and III are obtained from titanium anodes with 1 mm thick and 15 mm high strips with an equal gap between the strips and a coating height of 5 ...

10 mm. The distance between the anode and the mercury cathode was then 3 mm.

Figure 7 shows that the dependence of the cell voltage on the anode current density can be substantially improved by increasing the active true surface in the region near and far from the cathode. Curve II corresponds here to anodes whose active part consists of 2 mm thick and 12 mm high fully coated titanium strips with a gap of 2 mm between them, while curve I refers to the same type of anode as in Figure 6 with a 10 mm high coating.

A decrease in current density correspondingly increases the life of the active anode coating. The high height of the electrochemically active anode part in connection with a relatively small anode base surface and the profitably vertical fitting of the active real surface guarantee good emergency operation characteristics, even in the event of possible short circuits, and rapid removal of chlorine gas bubbles. Finally, the high height allows the current distribution to be placed inside the active anode part, which makes the use of the anode on both sides simple. The anode according to the invention thus fully meets all the requirements for safe and economical high-power operation.

Claims (2)

6 59269 χ, coated titanium anode, for high-power mercury cells for use in chlor-alkali electrolysis, for use in particular when the anode current densities (D ^) are greater than 10 kA / in ^, the anode having a plurality of metal strips (1) not arranged parallel to each other and fixed one or more of the common line (2, 3, 8), and coated with an activating agent in the area in which the actual surface (each of the metal strip coated with the long sides, bottom and end faces of the amount) of at least half of which is arranged perpendicular to the anode of the main plane of sunteen, characterized in that the coated area, measured below the anode, has a higher ruin b nm but not higher than 20 mm and that its true surface, up to heights of 7, £,: ·; ·, 10 mm and 15 mm, exceeds the projected anode surface (anode length x width) by at least 3 1 / 3-, 4-resp. 4 3/4 times. Titanium anode according to Claim 1, characterized in that a current supply contact (7) is formed in the line (8), which allows the anode to be used on both sides. 1. a titanium anode for a quadrupole heat exchanger for a lithium electrolyzer, excited for the anode 2 to a gauge (D ^,) of 10 kA / m, with an immersion and a tort an antal metal band (1), preferably och vilka är fast Förenade med en eller flere gemen-san.na ledningar (2,3,8 ^ och ett med etterande material hela rt omräde, vars verkliga yta (summan av längsidan, undersidan ccr. anordnats Atmonstone account for anodens entertainment plan, känneteck-n ad därav, att det belagda omradet, mätt frän anodens under-Suda, är nögre än 5 mm, men inte högre än 20 mm, och att dess verkliga yta upp account höjderna 7, 5 mm, 10 mm and 15 mm overturned anodytes (anodens längd x bredd) Atmiru; tone • 4- or 4 3/4-gangers 2. litananod enligt patentkravet l, kännetecknad darav, att pa ledningen (8 ) formats en strömmatningskontakt (7) soi ;: tilläter användning av anoden pa bägge sidor.