DE2833499A1 - ANODE FOR ELECTROLYTIC CELLS - Google Patents

Description

Dipl.-Ing. Th. Hoefer ,, 4βοο Bielefeld 1, the 28.701978

⁰ ' J Kreuzstrasse 32

Telephone (0521) 171072 - Telex 9-32449

% Bank accounts: Commerzbank AG, Bielefeld 6851471 (BLZ 48040035)

^ Spatkasse Bielefeld 72001563 (BLZ 48050161)

Postal check account: Hanover Office 68928-304

this. Current number: 4386/78

Ammi S.p.A., Via Po, 19 Rome / Italy

Electrolytic cell anode

The invention relates to an anode for electrolytic cells.

In the known electrolytic cells for the electrolysis of metals from their solutions, in particular zinc, the anodes are formed by flat or perforated panels made of an alloy lead-silver (Pb-Ag) (0.7 to 1% Ag).

Corresponding to the increased cost of silver, it leaves an electrolytic industrial investment that is thousands or tens of thousands

9098 07/0897

of anodes _s the investment costs rise very high and in addition, in view of the average service life of the anodes, which is relatively short, very high costs are necessary for ongoing maintenance

The object of the present invention is to provide _s anodes for electrolytic cells _9, the same performance a smaller amount of a lead-silver alloy = ^ need so that consequently the investment costs and ongoing maintenance costs of the installation are reduced

Another object of the invention is to provide anodes _{s s} a better circulation of the electrolyte within the cell ermöglichenο

A further object of the invention _s to enable the production of more solid anode with respect to known anodes and reduce the number of course conclusions, "which may result from their deformation", "

Is a broader object of the invention to provide anodes ,, _s that allow an easier Entertainment _s which beziehte to the periodic removal of anode sludge

These objects are achieved according to the invention in an anode for electrolytic cells characterized _s that are mounted on a rail for the supply of the current a plurality of filiform (kabeiförmigen) elements _9, a rigid support core with a fairing layer of a lead-silver alloy exhibit",

909807/0897

The core of each thread-like element can preferably be formed by a round rod or by a metallic tube be formed, which - preferably produced by extrusion - with a thin layer of a lead-silver alloy is dressed.

Furthermore, according to a further preferred embodiment of the invention, each adjacent pair of thread or cable-shaped elements doubled in the form of a U and attached to the rail with its upper (free) ends, wherein each element formed by a single thread-like element can be.

Preferably, the thread-like elements of each anode can be kept at a distance from one another, according to the tubular elements made of insulating material, which have the effect of stiffening these elements and the to keep neighboring cathodes at a distance.

Further features of the invention emerge from the subclaims.

909807/08 9 7

In the drawing, an embodiment of the invention is shown but not the invention limited.

Show it:

Pig. I is a perspective view of an anode according to the invention;

Fig. 2 is a perspective partial view on an enlarged scale Representation of a thread-like (cable-shaped) element of the anode;

Fig «, 3 is a vertical section in an enlarged view of the end of a thread-like Element in a modified version.

As the figures show, the anode according to the invention has a rail 1 as a power supply in a known per se Version with a core made of copper 2 and a coating made of metallic lead 3

Several elements 4 are connected to the rail 1, which essentially consists of a round aluminum rod 5 and - preferably by extrusion - with a layer of lead-silver alloy (up to 0.8 # Ag) are sheathed. Each element 4 is bent in the shape of a very narrow U and attached to the lead layer of the Rail 1 welded on.

909807/0897

The various elements 4, or rather the two arms of the various elements 4, are horizontal Pipes 7 held together from plastic, which are equipped at suitable intervals with transverse holes through which said elements 4 are passed through. These tubes 7 have the effect of strengthening the anode and making it more uniform To ensure distribution of the elements 4 and also the anode distance from the adjacent cathodes of the electrolytic cell.

According to the embodiment of an anode according to the invention In relation to known plate-shaped anodes, the anodes according to the invention have numerous advantages, namely inter alia:

A remarkable reduction in the weight of the lead-silver alloy with constant performance and a considerable reduction in investment costs and entertainment.

Better circulation of the electrolyte inside the Cell is given.

A greater strength of the anode and consequently an extension of the mean service life, which you can see from it shows that the number of short circuits caused by deformations the anodes usually caused decreased

Greater ease in fastening the anode head and thereby easier periodic maintenance of the cells.

0O98O7 / O89 ¹ /

In the illustrated in Figo 3 embodiment, the thread-like elements (instead of U-shaped doubled) by a cylindrical rod 4 formed _s which is welded at its ends to the lead sheath of the rail 1 and the inner at their ends a closing cover 8 made of plastic or _s carrying the other insulating material to contact the inner core made of aluminum 5 NIIT the electrolytic solution prevents "

This embodiment is particularly advantageous ₉ because the core 5 is designed in the form of a tube and not in the form of a round rod or in such a way with a diameter _s that makes bending into a misshapen element inadvisable «,

Example I ₀

An electrolytic cell having 21 anodes and 2o cathode is provided, the distance between the anodes is 9o nrnio Each anode is formed by Io double elements in the form of U-shaped formed arms of 1 meter length _s the distance between them is 2 cm. The elements Io are each formed by a round bar from AIU aluminum with a diameter of 3 _s by a now produced by extruding a thin layer having a thickness of 3 mm of an alloy of lead and silver. (o _s 8jä silver) is covered «Accordingly, the total length of the anode is evenly one meter and its total width is 56 cm. The total length of the submerged part of the U-shaped elements is evenly 88 cm _s the space requirement _{% of} the submerged anode is essentially the same as that anode, as is usual (88 cm by 57 cm) _{or the like}

909807/0897

-JT-

In the attached table 1, certain characteristics are given (active surface, weight of the lead-silver alloy, Cost of each anode) for two types of anodes, one of which (anode A) of the usual type is, while the second (anode B) is designed according to the invention. Both have the same space requirements.

The test of Table 1 shows _t (with the same external dimensions), with an anode according to the invention a 60% economic improvement over a conventional anode. Using the same table 1, one can also fix:

The cost of welding the panels of a conventional anode to a rail 1 and the same cost of the filamentary Elements 4 according to the invention are not indicated as they show limited correspondence, essentially in both cases not different. Therefore the statement about the two costs has not been explained further.

The cost of rolling the lead-silver plates has not been given: therefore a real comparison is the resulting costs better with an anode according to the invention.

The cost of extruding the filamentary elements is equivalent to what has been effectively limited for one Rated the number of elements built; it is evident that as this amount increases, the fixed cost of the procedure decrease in an acceptable manner; therefore, there is also a very advantageous one in relation to this point Specification of the real costs t> ei of an anode according to the invention.

909807/0897

Λ <0

In the attached table 2, one has the conditions of measurements, which in the course of several months of observation occurred periodically, collected in a cell (No. 3) equipped with anodes according to the invention was equipped, compared with the relative circumstances of the measurements carried out in identical Cells (No. 1 and 2) equipped with conventional anodes.

The information according to Table 2, which shows the variations, is often advantageous with regard to the amperometric Performance: These variations are often not assigned to the thread-like anodes, they are rather given by that the differences of the same order of magnitude can also be found in the cells tested: They are due to other reasons depending on exceptional situations occurring in the cell room: Erroneous measurements or errors in the indications of the weights of damaged cathodes; in incorrect calculations of the amps consumed per hour? not sufficient Contacts between the cathodes and the rail; Short circuits.

The anode density is increased in the case of the thread-like anodes, which results from the fact that the active surface area is lower is; this results in a voltage at the heads of the cell that exceeds approximately 0.35 volts of the usual cells,

Such an increase in the voltage value corresponds approximately evenly to lo% and translates into an increase in the accumulation of specific energyο

909807/0897

ΛΛ

The increased anode density increases the non-releasability of the lead of the anode so that consequently an increased durability of the metal results in the zinc cathodes and a longer service life of these anodes, which is already due to the limited amount of lead-silver alloy is beneficial.

Of course you can construct thread-like anodes, which have a different shape with a larger number of elements or with elements which have a larger one Have diameters and, corresponding to the exemplary embodiments, offer the same anode density or enlarged to a lesser extent are than the usual anodes.

In this case the result is an accumulation of the same or slightly lower energy than that in the ratio of the cells with flat anodes; the amount of lead is reduced in cathodes and extends the life of the anodes to achieve an even layer of coating «, it is necessary to increase the amount of lead-silver alloy su and the cost of the alloy and its manufacture,

The amount of lead-silver alloy can be reduced by reducing the thickness of the cladding layer and thereby a partial improvement in the service life of the anodes Theoretical mean service life of filamentary anodes (i.e. the service life of the natural solution of lead due to the lack of acid corrosion or short circuits) is obviously shorter than that of the traditional ones Anodes to an extent that is in proportion to the amount of the reduced lead-silver alloy (based on their Manufacture). It has been found that the great strength

909807/0897

- ie "-

soft the anodes according to the invention, and the remarkable consequent reduction in the number of Acid breaks or short circuits, results in an average life of the anodes according to the invention, which in is essentially the same as that of the known anodes «,

Example II

An electrolytic cell with 13 anodes and 12 cathodes is provided. The distance between the anodes is 90 mm; each anode is formed to be carried 2o elements ₉ bent into a TJ, with arms of 1.37 meters in length and distributed over the length of the current feeding rail 1 on one strand of O ₉ 8 m _e Each element contains a round aluminum rod having a diameter of 3 mm _s which consists of a layer of lead-silver alloy (o _s ' j% silver) with a thickness of 3 mm produced by extrusion ο

Accordingly, the full length of the anode is 1.37 meters and its full width is 80 cm and Depending on the mode of action, the submerged elements (in U ~ shape) are evenly 125 cm long determined «The space requirement of the immersed anode is essentially the same as that of a traditional one Anode (125 cm by 80 cm).

In the attached table 3, certain characteristic properties are given (active surface area; weight the alloy in the case of silver, cost of each anode) for two types of anodes, one of which (anode C) the traditional one Type corresponds, which has an anode surface of 2 square meters j the other (anode D) formed according to the invention

909807/0897

The attached table summarizes information about periodic measurements over the course of a few months. In one cell (no. ¹ O anodes are positioned according to the invention and in a same cell (No known anodes 5).

When examining Table 3, about which the same problems can be found with regard to costs, and Table H one can see that with the anodes according to the invention there is a% o% increased economic efficiency with regard to the voltage on the heads This is hardly higher than 0.05 - 0.1 V with regard to the resulting voltage in the other cell, although the lead life of the lead in the cathodes of both cells is practically the same

Even in a case as shown above, the theoretical average life of the anodes is in accordance with of the invention is less than the theoretical life of known anodes which are heavier.

However, practically the mean life of the anodes according to the invention is about the same as that of the known ones Anodes, due to the increased strength and the resulting lower number of acid fractures and the short circuits,

909807/0897

Appendix _Λ

Table 1: Properties and costs of a known anode (A) and an anode (B) according to the invention

with the same space requirement i

Active surface (m ² ):

Weight of Pb-Ag alloy (Kg)

Cost of Pb (1.25 DM / Kg) Cost of Ag (325, -DM / Kg) Cost of Al (3.85 DM / Kg) Cost _{(2ί52 DM / Kg)} of extrusion

Total costs DM 222.50 DM 86.30

or A 58.174 Anode B 12.80 1 ^ 72.5O 0.5 - 16.00 -150, - ~ 33.30 - - 1.40 ~ 35.60

Table 3: Properties and costs of a known anode (C) and an anode (D) according to the invention

Active surface ( (m ² ) anode
2 C. 75 Anode D
1.53 , 80 costs of the Pb 'C 1.25 DM / kg) ~ 136, 50 ~ Ä3 _t - costs of the Ag ( 325 - / kg) - 286, «-92 , 15 costs of the Al 3.85 DM / kg) - "" 4 , 35 Costs (2 52
of extrusion DM / kg) ^ 98

Total costs DIi 423.25 238.30

909807/0897

Table 2

To & ang B

Comparison between measurements in a cell

(No. 3) with anodes according to the invention

and in cells (No. 1 and No. 2) with known

Anodes.

Performance (amp er omeT; r i s ch)

large Zn / 1000 Amph cells

power
_p (amp erometric)

Cells

Content of Pb. in gr / t in the cathodes

Cells

1126 1103 1072 92.4 90.5 88.0 6th 9 26th 1162 1162 1157 95.3 95.3 94.9 5 6th 19th 1169 1159 1129 95.9 95.1 92.6 5 6th 35 . 1111 1157 1007 91.1 94.9 82.7 • 9 4 " 16. 1072 1138 1091 88.0 93.4 89.6 12th 8th 16 1134 1061 1091 93.1 87.0 89.6 7th 19th 9 1034 1038 1088 84.8 85.2 89.3 14th 11 20th 1053 1142 1057 86.4 93.7 86.7 7th 13th 20th 1122 1076 1134 92.1 88.3 93.0 8th 7th 16 1036 1069 1017 85.0 87.7 83.4 8th 12th 24 1099 1154 1045 90.2 94.6 85.7 8th 12th 22nd 1045 1146 1099 85.7 94.0 90.2 5 8th 15th 1180 1022 1076 96.8 83.9 88.3 9 5 8th 1084 1023 1073 88.9 83.9 88.0 IQ 13th 16 1131 1028 1087 92.8. 84.3 89.2 19th 14th 15th 1149 1169 • 1129 94.3 95.9 92.6 11 17th 22nd 1149 1111 1115 94.3 91.2 91.5 9 17th 27 - 1138 1166 1103 93.4 95.6 90.5 14th 20th 25th 1100 1176 1115 90.2 96.5 91.5 6th 17th 15th 1158 1176 1129 95.0 96.5 92.6 6th 20th 1153 1168 1157 94.6 95.9 94.9 14th 1134 1169 1080 93.0 95.9 88.6 6th 1133 1179 33.0 36.7 94.2

7/03 ^ 7

/ 14

attachment

Table 4 Comparison between measurements in a cell (No. 4) with anodes according to the invention and in a cell with known anodes (Hr, 5)

Lexstung. ·
(amperometric)
large Zn / 1000 amph
4th 5 1047 power
(amperometry ch)
%
4 5 85.9 Content of
in gr / t in
Cathodes
4th Pb
the
5 1052 1048 86.3 85.9 12th 11 1064 1136 87.4 93.2 10 14th 1023 1033 83.9 84.8 21st 24 1096 1010 89.9 82.9 25th 33 1070 1052 Ό7.8 86.3 16 22nd 1095 1032 89.9 84.7 14th 20th 1107 1158 90.8 95.1 - - 1133 1076 93.0 88.3 7th 10 1056 1094 86.6 89.8 - - 1089 1067 89.3 87.6 - - 1069 1062 87.7 87.1 - - 1088 ■ 1137 89.3 93 _S 4 - ■ - 1110 1114 9I ₅ O 91.5 17th 9 ^V 1007 1027 82.6 84 _S 2 - - 1001 1030 82.2 84.6 - - 1057 1088 • 86.4 89.3 - - 1055 1005 86.5 82.4 10 7th 1052 1139 86.3 93.4 8th - 1114 1129 91.4 93.8 - - 1042 1039 85 _S 7 85.3 13th 25th 1023 83.9 - -

Π 7 / Π θ. @ 1

Claims (1)

Claims 1.) Anode for electrolytic cells, characterized in that several thread-like elements (4.4 ^s ) are attached to a rail (1) for supplying the current, which have a rigid core as a holder with a covering layer (6) made of a lead - Silver alloy. 2.) Anode according to claim i, characterized in that each thread-like element by a round Rod (5.5 *) is formed by a thin layer (6) of a lead-silver alloy, preferably is encased by extrusion. 3 x) anode according to claim 1, characterized in that each thread-like element _s (4.4 ^f) is formed by a metallic tube (5 ^f) by means of a layer (6) of a lead-silver alloy, preferably by extrusion ^, is dressed « 4.) Anode according to claims 1 to 3 _9, characterized in ₉ that the round rod (5 ₉ 5 ^S ) within the thread-like element (H _b k ^) is formed from aluminum. 5.) Anode according to claims 1 to 4, characterized in that each pair of adjacent thread-like Elements (4,4 *) is doubled by a U-shape, the free ends of which are attached to the rail (1) are. 909807/0897 6o) anode according to claims 1 to 5 »characterized j that each thread-like element (4,4 ·) its lower end is provided with a cover made of insulating material " 7.) An anode according to claims 1 to 6 characterized in that the _{S s} that the thread-like elements (H, 4 ⁸⁾ are at equal distances from one another and by means of
pipes (7) or the like arranged thereon are made of insulating material * 8 _e ) Anode according to claims 1 to 7 _S characterized in that the thread-like elements (4 _S 4 ») are held together by means of tubular rods (7) made of plastic _s through their transverse holes (9) the thread-like elements (4 _S 4 ^f ) reach through _o