FR2538623A1 - PROCESS FOR MANUFACTURING POSITIVE TUBULAR PLATES FOR ACCUMULATORS - Google Patents

Abstract

In a process according to the invention for manufacturing tubular positive plates for accumulators, a mixture containing substantially Pb and Pb compounds is poured until complete filling from the end facing away from the connecting strip into the tubes tubular bags containing a lead core connected to said bar, and then the tube filling orifice is closed. The lead powder is granulated in a granulator 12 by adding H2SO4 and H2O in the form of dilute sulfuric acid and supplying oxygen. The still wet granulate 14 is subjected to a subsequent oxidation and a size classification adjusted to the filling space of the tubular bags. The tubes are then filled with the still wet fine aggregate forming the mixture, subsequently oxidized and classified. Application to the strengthening of safety conditions during the manufacture of accumulators. (CF DRAWING IN BOPI)

Description

The invention relates to a method for producing positive plates

  tubular batteries for accumulators, wherein a mixture containing substantially Pb and Pb compounds is poured from the opposite end of the connecting bar into leg tubes of the tubular pockets containing a lead core connected to the terminal strip , until they are full, and then the filling hole of

tubes is closed.

  It is already known to fill tubular positive accumulator plates with powder-shaped mixtures containing lead. Such mixtures are, for example, miniums, mixtures of lead powder and miniums in different amounts of mixture as well as pure lead powder This is

  generally from 65 to 80%, in particular

  75% Pb O and 20 to 35%,

% of Pb.

  The possibility of using these mixtures in the tubular plates is determined in the first line by their density after tamping, from which the mass density in the formed state is directly derived. The second criterion

  essential to the usefulness of mixtures as

  wise for tubular positive plates is the

  mability, that is, the degree of electrochemical efficiency

  than compared to the transformation of the starting mixture

  in Pb O 2 by electrochemical oxidation.

  With miniums, this degree of efficiency is maximum; in addition, the degree of oxidation with this

  matter is very favorable in the starting condition.

  Due to the high costs of this material, however, it is also used to a growing extent directly

  lead powder as it comes from grinding.

  Lead powder is basically very suitable because of its favorable price as filling material for tubular pockets of positive tubular plates. Lead powder can be obtained in

  effect with simple chemical reactions.

  However, the pink problem with the use of lead powder is that even slight irregularities in powder production cause manufacturing problems because they are the result of direct effects on the density after tamping. Different densities after tamping. in turn have an influence on the

capacity of the finished accumulator.

  Another disadvantage when using

  powder to fill the tube plates

  in that during the filling process, one does not

  can avoid a considerable development of dust.

  This makes necessary important measures to ventilate

  work places, in order to maintain

  limits the harmful effects on the health of

  lead compounds very reactive on the labor.

  All previous attempts to improve the

  truction and to automate these workplaces have proved relatively ineffective We are forced

  in addition to providing the workers at these locations with

  special dust masks and other costly measures resulting from the stipulations concerning the protection of the work. It has been further tried to form, by mixing with water lead dust, pasta which is only suitable, of course, for filling grid plates. In the grid, the pasta is subjected to a ripening process to reduce However, these pastes are not suitable for filling the relatively narrow tubes of tubular plates with a diameter of about 8 mm, the filling space then being further reduced by the core of the tube. lead and fins of

  centering with a thickness of about 3 mm.

  The object of the present invention is to produce a process of the type mentioned above, whereby the disadvantages occurring during the use of lead powder, in particular the fluctuating density after tamping and the development of dust, are avoided without that the considerable advantages of lead powder for filling tubular positive plates

be diminished.

  It is intended to solve this problem according to the present invention that lead powder is granulated in a granulator by adding H 2 SO 4 and HO 2, preferably in the form of dilute sulfuric acid and supplying oxygen, preferably air, that the still wet granulate is subjected to a subsequent oxidation and a size-adjusted classification on the filling space of the tubular pockets and that the tubes are filled by the fine granulate still wet forming the mixture, subsequently oxidized and classified, and which contains, because of the size classification, only grains that adapt closely to space

filling.

  It is essential for the process according to this

  invention that the granulate removed still wet granula-

  be in the still damp state with oxidation

  which is continued preferably until

  In addition, it is essential that the subsequently oxidized fine granulate is not poured in the dry state, but in the wet state in the dry state. Thus, the lead powder is converted into tribasic and tetrabasic lead sulphate, the first Pb O being then tetragonal converted to orthorhombic Pb O due to the reaction.

with water.

  It is especially advantageous to carry out the important subsequent oxidation step at the same time as the size classification which is preferably

a sieving process.

  An advantageous embodiment of the present invention provides that during the granulation, water is added and that during granulation the temperature in the granulator can be controlled and that a maximum value in the range of 75 is preferably reached. at 850 C By appropriate addition of water, avoid

  to exceed a certain temperature as well as the

  resultant tribasic lead sulphate. The addition of water should not be too high

  to produce a paste and no more granules.

  In practically practicing the process according to the present invention, it is conveniently provided that the addition of H 2 SO 4 and H 20 takes place in a first phase of the granulation process and then that granulation is continued without addition to the formation of a mixture of tribasic and tetrabasic lead sulphate and orthorhombic lead oxide with additions of tetragonal Pb O It is also appropriate to connect to the first phase a second phase of higher movement causing substantially the termination of the granulation and which is followed by a third phase for subsequent reaction, with

  a reduced intensity of movement.

  During the subsequent reaction, on the one hand, the content of the residual metal is reduced and, on the other hand, the

  voluntary training of basic lead sulphates.

  The addition of acid and water in the first phase should take place in 0.5 to 5 minutes.

  in the second phase takes place

  l to 6 minutes, especially about 3 minutes.

  The subsequent reaction in the third phase must be

  during a period of 6 to 8 minutes, in particular

bind about 7 minutes.

  In order to obtain an optimal chemical conversion of the lead compounds contained in the lead dust and, on the other hand, to maintain the temperature within certain limits, as well as to obtain an appropriate grain, it is necessary to add to the lead dust in the first phase 4.0 to 6.0% by weight of H 2 SO 4 and 7.0

to 9.0% by weight of H 0.

  The diluted sulfuric acid used

  a density of 1.2 to 1.5, in particular about 1.3 g / ml.

  While the process described above ensures

  a yield of fine granulate sieved from 65 to 75%, renders it

  The total amount of the process according to the present invention can be up to almost 100% when the granulate

  separated due to excessive size in the classi-

  The size application is broken up and granulated again in the granulator by adding water as well as subsequently oxidized and classified and the fine granulate obtained then is also used to fill the tubes. This process may be repeated until conversion into

  fine granulate of all the lead powder.

  Other features and benefits of the

  present invention will appear in the description

  The following detailed description of several embodiments with reference to the drawings, in which: FIG. 1 is a schematic side view of a tubular positive plate for an accumulator, the tubes of the tubular pockets provided at both ends being only shown, while the intermediate tubes formed identically do not appear for the simplicity of the drawing; Figure 2 is an enlarged section along the line II-II of Figure 1; and FIG. 3 is a schematic side view partially in section of a granulator that can be used with

  the process according to the present invention.

  In FIG. 1, lead cores 16 arranged

  at a certain distance from each other and having a di-

  about 3 mm extend from the lead terminal strip 15 in tubes 17 of a tubular pocket 11 which is constituted by a textile mesh and has an internal diameter of about 8 mm at predetermined distances on the length, it is expected on the lead cores 16 and all around the centering fins 18 which touch the inner wall of the tubes 17 and thus provide a central position to the lead cores 16 inside the tubes 17 While in the drawing one is respectively two diametrically opposed centering fins 18 which are alternately offset by 90, it is preferred to provide over a length of 0.5 m twice three distributed centering fins

uniformly on the periphery.

  The fine aggregate 14 '(FIG. 2) manufactured below

  below in the light of an example is poured in the manner shown in Figure 1 by the arrow f in the tubes 17 of the tubular pockets 11, the tubular plate being mounted upside down As soon as all the tubes 17 are filled,

  fixed a strip of plastic material 19 indicated

  in Figure 1 in the form of a body of

  closing on the lower ends of the tubes 17.

  Then, we can then return the tube plate to its normal position of use and insert it into a battery It is essential that the fine aggregate 14 'is fine enough to adapt to the filling space 13 between the core of 16 lead and the centering fins 18 and the tube 17 and be able to flow without difficulty in this filling space to obtain a good density after damage The compactness can be improved by shaking the tube plate during the filling process. FIG. 3 schematically illustrates the granulation process according to the present invention. The granulator 12 is rotatably mounted with its axis of rotation 20 in bearings 21, the rotation shaft 20 then being disposed obliquely with respect to the horizontal according to the invention. An angle equal to about 600 The granulator is constituted by a substantially obliquely corresponding container which is closed at the top by a cover 22 which is independent, is fixed relative to the granulator 12, this being able to be illustrated by the presence of a support 23 suggested to the left of Figure 3 and which is fixed to the frame

of the machine.

  Through the converge 22 are arranged an inlet connection 24 for air and lead dust and diametrically opposite an outlet connection

  for the addition of dilute sulfuric acid and the

  In addition between these two supports, the shaft 26 is passed through an agitator which preferably rotates in the opposite direction of

  the rotation shaft 20 of the granulator 12.

  It is indicated schematically in the granulator

the granulate that forms 14.

  The method according to the present invention

for example, as follows.

  The entry fitting 24 is used to introduce lead dust having, for example, 25% Pb and

% of Pb O in the granulator 12.

  It is assumed that the weight of the amount of dust

added is 100 kg.

  After all the amount of lead dust has been introduced into the slowly rotating granulator (number of revolutions = 100 revolutions / minute), diluted sulfuric acid is added over a period of about 60 to 80 seconds. stirrer then working with a speed

1000 rotations / minute.

  Assuming, as above, 100 kg of lead dust, 13 kg of sulfuric acid with a density of 1.3 g / ml is added, which corresponds to an additional quantity of 5.16 kg of H 2 SO 4 and 7.84 kg H 2 O. The heat of neutralization and oxidation as well as the heat produced by the mechanical movement of the material would normally increase the temperature of the aggregate much too much 14 As a result of the evaporation of water, the heat capacity of the granulate and the air conducted through the granulator 12, it is nevertheless possible to maintain below 850 C the temperature

maximum granulate.

  During granulation, no noticeable reaction

with the air can not occur.

  The actual granulation takes place as a result of the addition of acid for about 3 minutes,

  the agitator rotating as before at 1000 rpm.

  It is essential that a subsequent reaction takes place for about 7 minutes, during which the stirrer only rotates at 10 to 20% of the speed of the initial speed, which in this case corresponds to a speed of 100 to 200 rotations per minute. During this subsequent reaction, another quantity of water can be evaporated, the temperature then falling to about 600 ° C. The granulator thus exits a broth which must be discharged correspondingly by the connection.

output 25.

  Then, the granulate 14 is removed from the granulate

  12 and subjected to a sieving process to obtain a fine aggregate 14 '(Figure 2) which is sufficiently

  fluid inside the tubular pockets As this pro-

  sieving takes place in the air, subsequent oxidation takes place, from about 20% Pb to a residual lead content of about 11% The water content decreases at the same time to a residual moisture of 3 , 5% During sieving

  at least 0.9% of water is thus evaporated.

  It has been determined that by the method according to the present invention the bulk weight and the post-damage density of the fine aggregate can be very good.

  reproduced when the starting dust was homogeneous.

  Both values can vary by changing the concentration

  this possibility of variation is an essential advantage of this

  invention, because one can thereby satisfy without difficulty

  requirements relating to different types of

emulators.

  By aerating the granulation drum after the actual granulation process, at a slow speed, a considerable subsequent reaction effect can be obtained so that a direct result is obtained.

  sifted product, because of the high temperature of

  Null and Continued oxidation of the resulting material.

  Sieving is appropriate because there are always proportions of grain of excessive size with diameters of 1 to 5 mm The proportion in percent grain

  excessive size can be reduced by the type of addi-

acid.

  The sieved excess grain size can be crushed by increasing the speed of the agitator in the granulator (in the present example for example 2000 rotations / minute), and then it can be granulated again at normal speed with water and finally, further processed as above. The yield obtained by a single step process in suitable fine sieved granulate is about 65 to 75%. By using again the excess size grain, however, the total yield of the process can be increased up to The chemical reactions which proceed according to the process of the present invention are as follows: Pb O + H 2 SO 4 = Pb So 4 + H 2 (1) 2 Pb + 2 = 2 Pb O (2) It s processes of the present invention which provide heat by way of

  heat of neutralization or heat of oxidation.

  For further details, the following complexes are formed: 3 Pb O Pb SO 4 2 H 20 (tribasic lead sulphate) 4 Pb O Pb SO 4 (tetrabasic lead sulphate) Pb O first tetragonal found in the dust of lead is converted by reaction with

orthorhombic Pb O water.

  The remainder of the lead metal content is about 11%. Because the proportion of screened excessively sized grain is fractionated and again granulated by adding water, which can be repeated several times, the content of residual metal is reduced

even less than 0.5%.

  Sifting takes place in such a way that the size

  maximum grains of the fine granulate 14 'is 1 mm.

  Commercial tubular bags can be used. The current efficiencies with tubular plate formation according to the present invention are at least as good as for normal lead powder blends, but however, the problems associated with the use of lead powder are completely eliminated.

filling the tubesheets.

  After charge of the formation, the content of Pb O 2 is 81 to 86.6% The amount of charging current is about 113% of the theoretical charge quantity

necessary.

  Pb O 2 is present mainly as 3-Pb O 2

  in addition to lower amounts of a-Pb O 2.

  The minimum grain size of the granulate is about 25 μm. The surface of the individual grains is covered with crystals about 4 μm in length and 1 μm thick. They are very small for tetrabasic lead sulfate. aggregates

  obtained by excessively large grains are

  non uniform in grain size distribution.

  The thinnest part is obviously coherent only

  by water and breaks down during preparation

  for the test On the surface, there are also

  prismatic rates already described also structures

  tabular (tribasic lead sulphate).

  The longevity of accumulators equipped with tubular plates according to the present invention is even a little bit better than that of accumulators

  known equipped with positive tubular plates.

  An essential reason for the success of the process according to the present invention is the fact that the dust

  lead can be granulated quickly and appropriately

  Intended for use in intensive mixing devices by adding dilute sulfuric acid by granulation, is meant a process in which the individual grains of a powder agglutinate to form an agglomerate which can not be altered by mechanical stress.

  moderate It is decisive for the formation of such agglomerations

  mates to obtain the combination of the action of a liquid 11- with a chemical reaction between the components of this liquid and the solid matter The formation of a new phase allows first of all an agglomeration

  which goes beyond the effect of adhesion forces.

Claims (11)

CLAIMS I   A method of manufacturing tubular positive plates for accumulators, in which a mixture containing essentially Pb and Pb compounds is poured from the end facing the opposite of the bar   connection in the tubes of the tubular pockets   having a lead core connected to the terminal strip, until they are full, and then the filling opening of the tubes is closed,   characterized in that lead dust is granular   in a granulator (12), with addition of H.sub.2 O.sub.4 and H.sub.20, preferably in the form of dilute sulfuric acid and oxygen supply, preferably air inlet, in that the still wet granulate (14 ) is subjected to subsequent oxidation and classification by   set on the filling space (13) is   in the tubular pockets (11), and in that the tubes (11) are filled with the fine granulate (14 ')   moist, forming the mixture, oxidized subsequently and classi-   which does not contain, because of the classification   in size, that grains adapting closely to the filling pace (13).   Process according to claim 1, characterized in that during the granulation, water is added and in that during the granulation the temperature in the granulator can be controlled (12) and a maximum value is preferably reached in the range from 75 to 850 C.   The method of claim 1 or claim   2, characterized in that the addition of H 25 04 and H 2 O takes place in a first phase of the process of   granulation and then the granulation is continued without   further addition until a mixture of tribasic and tetrabasic lead sulphate and lead oxide is formed   orthorhombic with additions of Pb O tetragonal.   4 Process according to claim 3, characterized in that in the first phase is connected a second phase of greater intensity of movement substantially terminating the granulation and to which is connected a third phase for the subsequent reaction, with   a reduced intensity of movement.   Process according to Claim 3 or Claim 4, characterized in that the addition of acid and water in the first phase takes place for 0.5 to 5 minutes, preferably about 2 minutes.   Process according to one of Claims 3 to 5,   characterized in that the granulation takes place in the second phase for 1 to 6, in particular about 3 minutes.   Method according to one of Claims 3 to 6,   characterized in that the subsequent reaction of the third   phase takes place for 4 to 10, in particular about 7 minutes.   Method according to one of the preceding claims   dentes, characterized in that lead dust is added in the first phase 4.0 to 6.0% by weight   of H 2 SO 4 and 7.0 to 9.0% by weight of H 2 O.   Process according to one of the preceding claims   characterized in that the dilute sulfuric acid used has a density of 1.2 to 1.5, in particular about 1.3 g / ml -   Method according to one of the preceding claims   cedentes, characterized in that the subsequent oxidation   occurs during classification by size.   The process according to claim 10, characterized   in that the classification by size is killed by a sieving process.   Process according to one of the preceding claims   cedeentes, characterized in that the subsequent oxidation is continued until a lead content   residual from 5 to 15%, in particular about 11%.   Method according to one of the preceding claims   cedentes, characterized in that the granulate separated   the size classification due to excessive size is fractionated and granulated again in the granulator (12) by adding water as well as subsequently oxidized and classified, and in that the fine granulate (14 ') obtained so is used also for fill the tubes (11).