EP0060791A1 - Use of reinforced lead anodes for the electrolytic treatment of zinc in sulfate solution and method for their manufacture - Google Patents
Use of reinforced lead anodes for the electrolytic treatment of zinc in sulfate solution and method for their manufacture Download PDFInfo
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- EP0060791A1 EP0060791A1 EP82400468A EP82400468A EP0060791A1 EP 0060791 A1 EP0060791 A1 EP 0060791A1 EP 82400468 A EP82400468 A EP 82400468A EP 82400468 A EP82400468 A EP 82400468A EP 0060791 A1 EP0060791 A1 EP 0060791A1
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C7/00—Constructional parts, or assemblies thereof, of cells; Servicing or operating of cells
- C25C7/02—Electrodes; Connections thereof
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
- Y10T156/10—Methods of surface bonding and/or assembly therefor
Definitions
- the invention relates to lead anodes intended for the electrolytic production of zinc from acidic aqueous sulphate solutions and comprising a reinforcement.
- the invention also relates to a method of manufacturing such anodes.
- the nature of the metal constituting the insoluble anodes is chosen as a function of the following considerations: the anodes must resist corrosion in a sulfuric medium and in the presence of nascent oxygen, and the bias voltage acquired by the anode must be low. Indeed, in the production of a metal by electrolysis, the cost of energy is an important element of the cost price, and the energy yield of electrolytic reduction, which is partly determined by the anode polarization, does not can be overlooked.
- the problems relating to insoluble anodes are frequently envisaged in the context of electrolytic deposits of coverings with metals of high value, where the energy costs are less involved, while the qualities of the deposited metal are greater.
- the electrolytic production of metals is a heavy industry, where the problems of tonnages and handling acquire serious importance.
- This lead contains from 0.25 to 1.0 by weight of silver, which improves the mechanical strength of the anodes (increase in rigidity and hardness) as well as resistance to corrosion in the presence of impurities from the baths, in particular chlorides.
- the lead anodes are generally rectangular plates with geometric surfaces ranging from 0.55 to 1.7 square meters, thicknesses correspondingly from 8 to 16 mm approximately, and weights from 50 to 300 kg. It is specified that the anodic surfaces of the plates are double the geometric surfaces, the two plate faces being active as anode.
- an electrolysis hall producing 100,000 tonnes of zinc per year uses 2,376 tonnes of lead for the anodes, containing nearly 12 tonnes of silver, or nearly 10,900 plates with a unit weight of 218 kg. In an installation of this type the investment in anodes can reach 20% of the total investment.
- Electrodes with a mechanically robust metal stiffening frame, enclosed in a lead sheath. It is common in electrochemistry in general to use electrodes with an active surface suitable for the electrochemical application, plated on a core or an armature whose nature has been chosen to respond to a particular situation (price, compatibility with the active surface , machining facilities, mechanical strength, electrical conductivity, and others).
- French patent application No. 78 22839 published under number 2 399 490 proposes lead anodes formed from bundles of aluminum rods sheathed with silver lead. These anodes are intended to, in addition to saving lead to silver, allow better circulation of the electrolyte, but are not likely to replace conventional anodes in existing installations. Furthermore, it emerges from the description of this application that these sheathed aluminum anodes are more fragile than conventional anodes.
- the invention relates to a lead anode for the production of zinc, which is lightened thanks to an internal frame, the nature of the frame being such that the gains resulting from the reduction are not compensated by an additional manufacturing cost of the anodes, by the appearance of operating incidents, or an accelerated decommissioning. Of course it is essential that the frame cannot cause pollution of the baths.
- the invention provides a lead anode, intended for the electrolytic production of zinc, from aqueous sulphate solutions and comprising a reinforcement, characterized in that this reinforcement is made of a metal chosen from the group comprising titanium and zirconium trapped between two layers of lead.
- titanium and zirconium have mechanical properties, lightness and rigidity, which are practically equaled only by light alloys (aluminum, magnesium), these being unusable in the intended application. They are available on the market at a non-excessive price. Above all, they exhibit excellent corrosion resistance by passivation. If the anode reinforcement is exposed due to shocks or arcs consecutive to a short circuit, the anodic passivation protects the exposed metal, and locally suppresses the flow of current by establishment of a contact potential higher than that of lead coating.
- Perforated reinforcements by perforation, weaving, made of expanded metal, will preferably be used, in order to obtain the desired rigidity of the reinforcement by using less metal; moreover the openings and asperities of the reinforcement improve the adhesion of the lead layer.
- the invention proposes a method for manufacturing such anodes with internal armatures, which consists in placing the outer layers of lead at a temperature above 100 ° C. At temperatures above 100 °, lead is more malleable (plasticity and creepability increased, more favorable recrystallization properties).
- the lamination of a complex formed by the armature between two lead sheets will be suitably between 100 ° and 250 ° C.
- the anode thus produced weighs 66.9 kg, comprising 4.1 kg of titanium and 62.8 kg of lead at 0.5 X silver, or 0.314 kg of silver. This corresponds to 49.2 kg per square meter including 3 kg of titanium and 46.2 kg of lead at 0.5% silver (0.23 kg of silver).
- the lead to silver saving is therefore 114 kg (0.57 kg of silver) per square meter.
- an experimental cell was used equipped with the five anodes of Example 1, and with four cathodes, each between two successive anodes, and having an active surface of 8.52 dm 2 (geometric surface 4.26 dm 2 ).
- the power supply is stabilized in current at an adjustable value, the voltage between anodes and cathodes being measured.
- the bath initially formed in the cell to contain 170 g / 1 of free sulfuric acid and zinc sulfate at a concentration of 40 g / 1 counted as zinc metal, is maintained at these concentrations by adding a neutral solution zinc sulphate, contribution controlled by the conductivity of the bath; the cell is also equipped with an overflow.
- the excess bath which flows through this overflow usually called cell acid or return acid, constitutes purge of deconcentration in free acid, and is collected, and samples (average samples) which are dosed to control the operation of the experimental facility.
- Example 2 The use of anodes according to Example 2 makes it possible to immobilize only about 30% of the quantity of lead and silver immobilized in conventional installations.
- the weight of the anodes is reduced to 31% of the conventional weight. Given the current price of titanium frameworks, investments in anodes would be reduced by 45%.
- the reinforcing structures were perforated sheet metal, wire mesh and woven metal, and expanded metal. With the perforated sheet, rolling around 200 ° is suitable, and a preparation of the sheet by etching has proved to be advantageous.
- the filling of lead by casting lead in a mold where the reinforcement is kept centered is particularly recommended when the reinforcement structure is loose (expanded metal, large mesh netting).
- the tight mesh and weaving can be covered with lead by spraying molten lead, by a known process. Lining by immersion in molten lead of suitably prepared preceding armature structures gives good results if the temperature of the molten lead and the rate of emersion are precisely controlled.
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Abstract
Description
L'invention se rapporte à des anodes de plomb destinées à l'élaboration électrolytique de zinc à partir de solutions aqueuses acides de sulfate et comportant une armature. L'invention se rapporte également à un procédé de fabrication de telles anodes.The invention relates to lead anodes intended for the electrolytic production of zinc from acidic aqueous sulphate solutions and comprising a reinforcement. The invention also relates to a method of manufacturing such anodes.
A l'heure actuelle la majeure partie du zinc élaboré à partir de minerai est obtenue par hydrométallurgie avec production de zinc métallique par électrolyse de solutions aqueuses acides de sulfate, dans des cuves équipées d'anodes insolubles. Les bains d'électrolyse contiennent de l'acide sulfurique libre, et le dépôt de zinc à la cathode s'accompagne à l'anode d'un dégagement d'oxygène et formation d'acide sulfurique libre.At present, most of the zinc produced from ore is obtained by hydrometallurgy with the production of metallic zinc by electrolysis of aqueous acidic sulphate solutions, in tanks equipped with insoluble anodes. The electrolysis baths contain free sulfuric acid, and the deposit of zinc at the cathode is accompanied at the anode by the evolution of oxygen and the formation of free sulfuric acid.
La nature du métal constituant les anodes insolubles est choisie en fonction des considérations suivantes : les anodes doivent résister à la corrosion en milieu sulfurique et en présence d'oxygène naissant, et la tension de polarisation acquise par l'anode doit être basse. En effet, dans l'élaboration d'un métal par électrolyse, le coût de l'énergie est un élément important du prix de revient, et le rendement énergétique de réduction électrolytique, qui est déterminé en partie par la polarisation d'anode, ne peut être négligé. Les problèmes relatifs aux anodes insolubles sont fréquemment envisagés dans le cadre des dépôts électrolytiques de recouvrements par des métaux de valeur élevée, où les coûts d'énergie interviennent moins, tandis que les qualités du métal déposé sont plus importantes. En outre l'élaboration électrolytique de métaux est une industrie lourde, où les problèmes de tonnages et de manutention acquièrent une importance sérieuse.The nature of the metal constituting the insoluble anodes is chosen as a function of the following considerations: the anodes must resist corrosion in a sulfuric medium and in the presence of nascent oxygen, and the bias voltage acquired by the anode must be low. Indeed, in the production of a metal by electrolysis, the cost of energy is an important element of the cost price, and the energy yield of electrolytic reduction, which is partly determined by the anode polarization, does not can be overlooked. The problems relating to insoluble anodes are frequently envisaged in the context of electrolytic deposits of coverings with metals of high value, where the energy costs are less involved, while the qualities of the deposited metal are greater. In addition, the electrolytic production of metals is a heavy industry, where the problems of tonnages and handling acquire serious importance.
Les contraintes de résistance à la corrosion et de polarisation anodique faible ont conduit à choisir, de façon pratiquement universelle le plomb pour constituer le métal d'anode. Ce plomb contient de 0,25 à 1,0 en poids d'argent, qui améliore la tenue mécanique des anodes (augmentation de la rigidité et de la dureté) ainsi que la résistance à la corrosion en présence d'impuretés des bains, notamment chlorures.The constraints of resistance to corrosion and low anodic polarization led to choosing, practically universally, lead to constitute the anode metal. This lead contains from 0.25 to 1.0 by weight of silver, which improves the mechanical strength of the anodes (increase in rigidity and hardness) as well as resistance to corrosion in the presence of impurities from the baths, in particular chlorides.
Les anodes de plomb sont généralement des plaques de forme rectangulaire avec des surfaces géométriques allant de 0,55 à 1,7 mètre carré, des épaisseurs allant corrélativement de 8 à 16 mm environ, et des poids de 50 à 300 kg. On précise que les surfaces anodiques des plaques sont doubles des surfaces géométriques, les deux faces de plaque étant actives comme anode. Comme ordre de grandeur, un hall d'électrolyse produisant 100.000 tonnes de zinc par an met en oeuvre pour les anodes 2 376 tonnes de plomb, contenant près de 12 tonnes d'argent, soit près de 10 900 plaques d'un poids unitaire de 218 kg. Dans une installation de ce type l'investissement en anodes peut at- teindre 20 % de l'investissement total. Il est clair qu'une réduction de poids des anodes aurait des répercussions sensibles sur le capital investi, ainsi que sur les frais relatifs aux manutentions (chaque anode est extraite du bain 6 à 8 fois par an, ce qui représente pour l'ensemble de 220 à 300 manipulations journalières). Mais les propriétés mécaniques du plomb utilisé ne permettent pas de réduire l'épaisseur des plaques sans risquer des déformations aux manutentions et en opération, et des détériorations prématurées.The lead anodes are generally rectangular plates with geometric surfaces ranging from 0.55 to 1.7 square meters, thicknesses correspondingly from 8 to 16 mm approximately, and weights from 50 to 300 kg. It is specified that the anodic surfaces of the plates are double the geometric surfaces, the two plate faces being active as anode. As an order of magnitude, an electrolysis hall producing 100,000 tonnes of zinc per year uses 2,376 tonnes of lead for the anodes, containing nearly 12 tonnes of silver, or nearly 10,900 plates with a unit weight of 218 kg. In an installation of this type the investment in anodes can reach 20% of the total investment. It is clear that a reduction in the weight of the anodes would have significant repercussions on the capital invested, as well as on the costs relating to handling (each anode is removed from the bath 6 to 8 times per year, which represents for the whole of 220 to 300 daily manipulations). However, the mechanical properties of the lead used do not make it possible to reduce the thickness of the plates without risking deformations during handling and in operation, and premature deterioration.
On peut envisager d'utiliser des anodes composites avec une armature de raidissement en métal mécaniquement robuste, enfermée dans une gaine de plomb. Il est courant en électrochimie en général d'utiliser des électrodes avec une surface active adaptée à l'application électrochimique, plaquée sur une âme ou une armature dont la nature a été choisie pour répondre à une situation particulière (prix, compatibilité avec la surface active, facilités d'usinage, tenue mécanique, conductivité électrique, et autres).One can consider using composite anodes with a mechanically robust metal stiffening frame, enclosed in a lead sheath. It is common in electrochemistry in general to use electrodes with an active surface suitable for the electrochemical application, plated on a core or an armature whose nature has been chosen to respond to a particular situation (price, compatibility with the active surface , machining facilities, mechanical strength, electrical conductivity, and others).
Ainsi la demande de brevet français n° 78 22839 publiée sous le numéro 2 399 490, propose des anodes de plomb formées de faisceaux de tiges d'aluminium gainées de plomb à l'argent. Ces anodes sont prévues pour, outre les économies de plomb à l'argent, permettre une meilleure circulation de l'électrolyte, mais ne sont pas susceptibles de remplacer les anodes classiques dans les installations existantes. En outre il ressort de la description de cette-demande que ces anodes en aluminium gainées sont plus fragiles que les anodes classiques.Thus, French patent application No. 78 22839 published under number 2 399 490, proposes lead anodes formed from bundles of aluminum rods sheathed with silver lead. These anodes are intended to, in addition to saving lead to silver, allow better circulation of the electrolyte, but are not likely to replace conventional anodes in existing installations. Furthermore, it emerges from the description of this application that these sheathed aluminum anodes are more fragile than conventional anodes.
Dans sa conception générale, l'invention a pour objet une anode en plomb pour l'élaboration du zinc, qui soit allégée grâce à une armature intérieure, la nature de l'armature étant telle que les gains résultant de l'allègement ne soient pas compensés par un surcoût de fabrication des anodes, par l'apparition d'incidents en fonctionnement, ou une mise hors d'usage accélérée. Bien entendu il est primordial que l'armature ne puisse provoquer une pollution des bains.In its general design, the invention relates to a lead anode for the production of zinc, which is lightened thanks to an internal frame, the nature of the frame being such that the gains resulting from the reduction are not compensated by an additional manufacturing cost of the anodes, by the appearance of operating incidents, or an accelerated decommissioning. Of course it is essential that the frame cannot cause pollution of the baths.
Dans ce but l'invention propose une anode de plomb, destinée à l'élaboration électrolytique de zinc, à partir de solutions aqueuses de sulfate et comportant une armature, caractérisée en ce que cette armature est en un métal choisi dans le groupe comprenant titane et zirconium emprisonnée entre deux couches de plomb.To this end, the invention provides a lead anode, intended for the electrolytic production of zinc, from aqueous sulphate solutions and comprising a reinforcement, characterized in that this reinforcement is made of a metal chosen from the group comprising titanium and zirconium trapped between two layers of lead.
Ces métaux, titane et zirconium présentent des propriétés mécaniques, légèreté et rigidité, qui ne sont pratiquement égalées que par les alliages légers (aluminium, magnésium), ceux- ci étant inutilisables dans l'application visée. Ils sont disponibles sur le marché à un prix non excessif. Et surtout, ils présentent une tenue à la corrosion excellente par passivation. Si l'armature d'anode vient à être mise à nu à la suite de chocs ou d'arcs consécutifs à un court-circuit, la passivation anodique protège le métal mis à nu, et supprime localement le passage de courant par établissement d'un potentiel de contact supérieur à celui du revêtement de plomb.These metals, titanium and zirconium have mechanical properties, lightness and rigidity, which are practically equaled only by light alloys (aluminum, magnesium), these being unusable in the intended application. They are available on the market at a non-excessive price. Above all, they exhibit excellent corrosion resistance by passivation. If the anode reinforcement is exposed due to shocks or arcs consecutive to a short circuit, the anodic passivation protects the exposed metal, and locally suppresses the flow of current by establishment of a contact potential higher than that of lead coating.
Les avantages de faible densité, de prix et de disponibilité commerciale sont particulièrement marqués pour le titane qui sera préféré.The advantages of low density, price and commercial availability are particularly marked for the titanium which will be preferred.
On utilisera de préférence des armatures ajourées, par perforation, tissage, en métal déployé, afin d'obtenir la rigidité désirée de l'armature en utilisant moins de métal ; de plus les ajours et aspérités de l'armature améliorent l'adhérence de la couche de plomb.Perforated reinforcements, by perforation, weaving, made of expanded metal, will preferably be used, in order to obtain the desired rigidity of the reinforcement by using less metal; moreover the openings and asperities of the reinforcement improve the adhesion of the lead layer.
Sous un autre aspect l'invention propose un procédé de fabrication de telles anodes à armatures internes, qui consiste à mettre en place les couches extérieures de plomb à une température supérieure à 100°C. Aux températures supérieures à 100°, le plomb est plus malléable (plasticité et aptitude au'fluage augmentées, propriétés de recristallisation plus favorables).In another aspect, the invention proposes a method for manufacturing such anodes with internal armatures, which consists in placing the outer layers of lead at a temperature above 100 ° C. At temperatures above 100 °, lead is more malleable (plasticity and creepability increased, more favorable recrystallization properties).
Notamment le laminage d'un complexe formé par l'armature entre deux feuilles de plomb se fera convenablement entre 100° et 250°C.In particular, the lamination of a complex formed by the armature between two lead sheets will be suitably between 100 ° and 250 ° C.
Il est également possible de recouvrir l'armature avec du plomb en cours de solidification, soit par immersion de l'armature dans le plomb fondu, par surmoulage du plomb dans un moule convenable, ou projection de plomb fondu par pulvérisation sur l'armature.It is also possible to cover the framework with lead in the course of solidification, either by immersion of the framework in molten lead, by overmolding of the lead in a suitable mold, or projection of molten lead by spraying on the framework.
Les caractéristiques et avantages de l'invention ressortiront d'ailleurs de la description qui va suivre à titre d'exemple.The characteristics and advantages of the invention will become apparent from the description which follows by way of example.
Pour déterminer les conditions de fabrication et d'utilisation d'anodes pour installations industrielles, on a réalisé dans un premier temps des anodes expérimentales de la façon suivante :
- Une plaque de titane d'épaisseur 1,0 mm, de longueur 250 mm et de largeur 150 mm, percée de trous de 6 mm de diamètre à entr'axe de 10 mm (taux d'ajourage 30 % environ) est placée en sandwich entre deux plaques de plomb à 0,5 % d'argent, de mêmes longueur et largeur que la plaque de titane, et d'épaisseur 2,86 mm. Cet ensemble, porté à 200°C, a été laminé dans le sens dela longueur, avec une distance entre cylindres de laminoir de 5 mm. Après laminage on a effectué un détourage au ras de l'armature de titane ; le sandwich présente alors les cotes suivantes : longueur 264 mm, largeur 150,5 mm, épaisseur totale 5,05 mm, épaisseur de l'armature de titane 0,95 mm. Puis on a exécuté sur la tranche du sandwich un cordon de soudure thermique avec, comme métal d'apport, du plomb à 0,5 °o d'argent.
- A titanium plate 1.0 mm thick, 250 mm long and 150 mm wide, pierced with 6 mm diameter holes with a 10 mm center distance (openwork rate approximately 30%) is sandwiched between two 0.5% silver lead plates, the same length and width as the titanium plate, and 2.86 mm thick. This assembly, brought to 200 ° C., was rolled lengthwise, with a distance between rolling mill rolls of 5 mm. After rolling, a trimming was carried out flush with the titanium frame; the sandwich then has the following dimensions: length 264 mm, width 150.5 mm, total thickness 5.05 mm, thickness of the titanium frame 0.95 mm. Then a thermal weld bead was run on the edge of the sandwich with, as filler metal, lead at 0.5 ° o silver.
Cinq anodes ont été ainsi réalisées pour mise en oeuvre dans une cellule d'électrolyse de laboratoire, deux anodes présentant des défauts de recouvrement, respectivement de 1 et 4 cm2 de surface, exécutés volontairement par enlèvement local de plomb.Five anodes were thus produced for implementation in a laboratory electrolysis cell, two anodes having covering defects, of 1 and 4 cm 2 of surface respectively, carried out voluntarily by local removal of lead.
Les essais de fonctionnement qui seront décrits plus loin ayant été concluants, des anodes pour installations industrielles seront fabriquées ainsi :The functional tests which will be described later having been conclusive, anodes for industrial installations will be manufactured as follows:
Pour remplacer des anodes de plomb de surface géométrique 1,36 m2 et d'épaisseur 14 mm, ayant un poids de 218 kg soit 160,3 kg/m2 et contenant 0,5 % d'argent (1,09 kg soit 0,80 kg/m2) on réalise des anodes comme suit :
- De part et d'autre d'une plaque de titane de 1,0 mm d'épaisseur, de 1,50 m de longueur et 0,86 m de largeur, et percée de trous de 6 mm de diamètre à entr'axe de 10 mm, en alignements orientés à 45° de la longueur on dispose deux feuilles de plomb à 0,5 % d'argent, d'épaisseur 2,86 mm et de mêmes dimensions que la plaque de titane. L'ensemble porté à 200°C est laminé à cette température entre cylindres de laminoir distants de 5,0 mm. L'anode est ensuite détourée à ses dimensions définitives (1,58 m x 0,86 m) puis garnie sur ses tranches d'un cordon de soudure avec du plomb à 0,5 % d'argent comme métal d'apport.
- On either side of a titanium plate 1.0 mm thick, 1.50 m long and 0.86 m wide, and pierced with 6 mm diameter holes with a center-to-center 10 mm, in alignments oriented at 45 ° in length, there are two sheets of lead 0.5% silver, 2.86 mm thick and of the same dimensions as the titanium plate. The assembly brought to 200 ° C. is rolled at this temperature between rolling mill cylinders spaced 5.0 mm apart. The anode is then cut to its final dimensions (1.58 mx 0.86 m) and then furnished on its edges with a weld bead with lead containing 0.5% silver as the filler metal.
L'anode ainsi fabriquée pèse 66,9 kg, comprenant 4,1 kg de titane et 62,8 kg de plomb à 0,5 X d'argent, soit 0,314 kg d'argent. Ceci correspond à 49,2 kg au mètre carré dont 3 kg de titane et 46,2 kg de plomb à 0,5 % d'argent (0,23 kg d'argent).The anode thus produced weighs 66.9 kg, comprising 4.1 kg of titanium and 62.8 kg of lead at 0.5 X silver, or 0.314 kg of silver. This corresponds to 49.2 kg per square meter including 3 kg of titanium and 46.2 kg of lead at 0.5% silver (0.23 kg of silver).
L'économie de plomb à l'argent est donc de 114 kg (0,57 kg d'argent) par mètre carré.The lead to silver saving is therefore 114 kg (0.57 kg of silver) per square meter.
Pour les essais de fonctionnement on a utilisé une cellule expérimentale équipée des cinq anodes de l'exemple 1, et de quatre cathodes, chacune entre deux anodes successives, et présentant une surface active de 8,52 dm2 (surface géométrique 4,26 dm2). La source d'alimentation électrique est stabilisée en courant à une valeur ajustable, la tension entre anodes et cathodes étant mesurée. Le bain, constitué au départ dans la cellule pour contenir 170 g/1 d'acide sulfurique libre et du sulfate de zinc a une concentration de 40 g/1 comptée en zinc métal, est maintenu à ces concentrations par apport d'une solution neutre de sulfate de zinc, apport asservi à la conductivité du bain ; la cellule est en outre équipée d'un trop plein. L'excès de bain qui s'écoule par ce trop plein, dit usuellement acide de cellule ou acide de retour, constitue purge de déconcentration en acide libre, et est recueilli, et on effectue des prélèvements (échantillons moyens) qui sont dosés pour contrôler le fonctionnement de l'installation expérimentale.For the operating tests, an experimental cell was used equipped with the five anodes of Example 1, and with four cathodes, each between two successive anodes, and having an active surface of 8.52 dm 2 (geometric surface 4.26 dm 2 ). The power supply is stabilized in current at an adjustable value, the voltage between anodes and cathodes being measured. The bath, initially formed in the cell to contain 170 g / 1 of free sulfuric acid and zinc sulfate at a concentration of 40 g / 1 counted as zinc metal, is maintained at these concentrations by adding a neutral solution zinc sulphate, contribution controlled by the conductivity of the bath; the cell is also equipped with an overflow. The excess bath which flows through this overflow, usually called cell acid or return acid, constitutes purge of deconcentration in free acid, and is collected, and samples (average samples) which are dosed to control the operation of the experimental facility.
La seule variable retenue pour les essais a été la densité de courant ; en effet, on peut constater que les concentrations en acide sulfurique libre et en sulfate de zinc diffèrent peu d'une installation à l'autre dans le monde, et que dans les gammes pratiquées les variations de concentration sont pratiquement sans effet sur le processus électrochimique anodique.The only variable retained for the tests was the current density; indeed, it can be seen that the concentrations of free sulfuric acid and of zinc sulfate differ little from one installation to another in the world, and that in the ranges practiced the variations in concentration have practically no effect on the electrochemical process. anodic.
Par ailleurs les essais ont été conduits par périodes d'activité de 48 heures environ à courant constant, après quoi les cathodes étaient extraites, pesées et débarrassées du zinc déposé, tandis que les anodes étaient laissées dans le bain, sans passage de courant. Les résultats sont présentés dans le tableau suivant.
Les valeurs du tableau sont pratiquement identiques aux valeurs que l'on obtient avec les anodes classiques en plomb massif à même teneur en argent.The values in the table are practically identical to the values obtained with conventional solid lead anodes with the same silver content.
) Après 56 jours d'essais, comprenant 40 jours de fonctionnement actif cumulé, et 16 jours d'arrêt cumulé les anodes ont été retirées de la cellule, lavées, brossées et examinées. Les surfaces de plomb à l'argent ne présentaient aucune altération anormale. Le titane mis à nu (défauts provoqués) était intact et aucune amorce de décollement du plomb autour de ces défauts n'était visible.) After 56 days of testing, including 40 days of cumulative active operation, and 16 days of cumulative shutdown, the anodes were removed from the cell, washed, brushed and examined. The lead to silver surfaces showed no abnormal alteration. The exposed titanium (defects caused) was intact and no lead was observed around these defects.
L'ensemble de ces essais manifeste que sous les aspects de fonctionnement électrochimique et de résistance à la corrosion les anodes à armature de titane sont équivalentes aux anodes en plomb massif.All of these tests show that under the aspects of electrochemical functioning and corrosion resistance the anodes with titanium reinforcement are equivalent to the solid lead anodes.
L'utilisation d'anodes selon l'exemple 2 permet de n'immobiliser que 30 % environ de la quantité de plomb et d'argent immobilisé dans les installations classiques. Le poids des anodes est réduit à 31 % du poids classique. Compte tenu du prix actuel des armatures de titane, les investissements en anodes seraient réduits de 45 %.The use of anodes according to Example 2 makes it possible to immobilize only about 30% of the quantity of lead and silver immobilized in conventional installations. The weight of the anodes is reduced to 31% of the conventional weight. Given the current price of titanium frameworks, investments in anodes would be reduced by 45%.
Un certain nombre d'essais ont été exécutés pour évaluer les procédés de fabrication les plus efficaces en rapport avec les structures d'armature. Les structures d'armature étaient la tôle perforée, les grillage et métal tissé, et le métal déployé. Avec la tôle perforée, le laminage vers 200° convient, et une préparation de la tôle par dépolissage s'est avérée intéressante.A number of tests have been performed to assess the most efficient manufacturing processes related to the reinforcement structures. The reinforcing structures were perforated sheet metal, wire mesh and woven metal, and expanded metal. With the perforated sheet, rolling around 200 ° is suitable, and a preparation of the sheet by etching has proved to be advantageous.
Le garnissage de plomb par coulée du plomb dans un moule où l'armature est maintenue centrée est particulièrement recommandé lorsque la structure d'armature est lâche (métal déployé, grillage à grandes mailles).The filling of lead by casting lead in a mold where the reinforcement is kept centered is particularly recommended when the reinforcement structure is loose (expanded metal, large mesh netting).
Les grillages et tissages serrés peuvent être recouverts de plomb par pulvérisation de plomb fondu, par un procédé connu. Le garnissage par immersion dans le plomb fondu des structures d'armature précédentes convenablement préparées donne de bons résultats si la température du plomb fondu et la vitesse d'émersion sont contrôlées avec précision.The tight mesh and weaving can be covered with lead by spraying molten lead, by a known process. Lining by immersion in molten lead of suitably prepared preceding armature structures gives good results if the temperature of the molten lead and the rate of emersion are precisely controlled.
Des essais avec le zirconium à la place du titane ont confirmé que le comportement mécanique et électrochimique du zirconium était au moins aussi bon qu'avecle titane. La densité supérieure du zirconium (6,5) ne joue pratiquement pas sur le poids des anodes (1,3 kg de supplément au m soit 2 %) mais se répercute quelque peu sur le tonnage utilisé (45 % en supplément).Tests with zirconium in place of titanium confirmed that the mechanical and electrochemical behavior of zirconium was at least as good as with titanium. The higher density of zirconium (6.5) has practically no effect on the weight of the anodes (1.3 kg of supplement per m or 2%) but has some repercussions on the tonnage used (45% in addition).
Bien entendu l'invention n'est pas limitée aux exemples décrits, mais en embrasse toutes les variantes d'exécution.Of course, the invention is not limited to the examples described, but embraces all the variant embodiments.
Claims (9)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT82400468T ATE15700T1 (en) | 1981-03-18 | 1982-03-15 | USE OF REINFORCED LEAD ANODES FOR THE ELECTROLYTIC TREATMENT OF ZINC IN SULPHATE SOLUTION AND PROCESS FOR THEIR PRODUCTION. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8105396 | 1981-03-18 | ||
| FR8105396A FR2502188B1 (en) | 1981-03-18 | 1981-03-18 | REINFORCED LEAD ANODES FOR THE ELECTROLYTIC PROCESSING OF ZINC IN SULPHATE SOLUTION, AND PREPARATION METHOD |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0060791A1 true EP0060791A1 (en) | 1982-09-22 |
| EP0060791B1 EP0060791B1 (en) | 1985-09-18 |
Family
ID=9256368
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP82400468A Expired EP0060791B1 (en) | 1981-03-18 | 1982-03-15 | Use of reinforced lead anodes for the electrolytic treatment of zinc in sulfate solution and method for their manufacture |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US4437965A (en) |
| EP (1) | EP0060791B1 (en) |
| JP (1) | JPS57164997A (en) |
| AT (1) | ATE15700T1 (en) |
| AU (1) | AU552085B2 (en) |
| CA (1) | CA1169813A (en) |
| DE (1) | DE3266279D1 (en) |
| ES (1) | ES8303549A1 (en) |
| FR (1) | FR2502188B1 (en) |
| NO (1) | NO160088C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0194321A1 (en) * | 1985-03-02 | 1986-09-17 | Bleiindustrie GmbH vorm. Jung + Lindig | Method for manufacturing lead anodes for zinc electrowinning, and lead anode produced thereby |
| WO2000042241A1 (en) * | 1999-01-13 | 2000-07-20 | Rsr Technologies, Inc. | Electrowinning anodes which rapidly produce a protective oxide coating |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7455715B2 (en) * | 2001-07-13 | 2008-11-25 | Teck Cominco Metals Ltd. | Heap bioleaching process for the extraction of zinc |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB869618A (en) * | 1958-07-24 | 1961-05-31 | Ici Ltd | Lead-acid storage cells |
| GB1394694A (en) * | 1971-10-28 | 1975-05-21 | Montedison Spa | Lead acid accumulator or storage battery with supporting and/or connecting parts made of lihgt alloys |
| US3907659A (en) * | 1974-04-04 | 1975-09-23 | Holmers & Narver Inc | Composite electrode and method of making same |
| FR2399490A1 (en) * | 1977-08-03 | 1979-03-02 | Ammi Spa | Anode for electrolytic mfr. of zinc - using aluminium rods coated with lead-silver alloy to reduce anode cost |
| FR2407278A1 (en) * | 1977-10-27 | 1979-05-25 | Jeantet | Chromium plating anode - comprises lead alloy sheath into which is screw threaded metal of greater electrical conductivity |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1302959A (en) | 1919-05-06 | Production of electrodes | ||
| US3844921A (en) | 1972-12-18 | 1974-10-29 | Exxon Production Research Co | Anode containing pin-type inserts |
| DE2642559B1 (en) | 1976-09-22 | 1978-02-23 | Heraeus Elektroden | PROCESS FOR RENOVATING EFFECTIVE ELECTRODE AREAS OF METAL ELECTRODES FOR ELECTROLYSIS CELLS |
| US4260470A (en) | 1979-10-29 | 1981-04-07 | The International Nickel Company, Inc. | Insoluble anode for electrowinning metals |
| ZA817441B (en) | 1980-11-21 | 1982-10-27 | Imi Kynoch Ltd | Anode |
-
1981
- 1981-03-18 FR FR8105396A patent/FR2502188B1/en not_active Expired
-
1982
- 1982-03-11 US US06/357,195 patent/US4437965A/en not_active Expired - Fee Related
- 1982-03-15 EP EP82400468A patent/EP0060791B1/en not_active Expired
- 1982-03-15 DE DE8282400468T patent/DE3266279D1/en not_active Expired
- 1982-03-15 AT AT82400468T patent/ATE15700T1/en not_active IP Right Cessation
- 1982-03-16 CA CA000398462A patent/CA1169813A/en not_active Expired
- 1982-03-17 NO NO820866A patent/NO160088C/en unknown
- 1982-03-17 JP JP57042494A patent/JPS57164997A/en active Granted
- 1982-03-17 ES ES510520A patent/ES8303549A1/en not_active Expired
- 1982-03-17 AU AU81623/82A patent/AU552085B2/en not_active Ceased
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB869618A (en) * | 1958-07-24 | 1961-05-31 | Ici Ltd | Lead-acid storage cells |
| GB1394694A (en) * | 1971-10-28 | 1975-05-21 | Montedison Spa | Lead acid accumulator or storage battery with supporting and/or connecting parts made of lihgt alloys |
| US3907659A (en) * | 1974-04-04 | 1975-09-23 | Holmers & Narver Inc | Composite electrode and method of making same |
| FR2399490A1 (en) * | 1977-08-03 | 1979-03-02 | Ammi Spa | Anode for electrolytic mfr. of zinc - using aluminium rods coated with lead-silver alloy to reduce anode cost |
| FR2407278A1 (en) * | 1977-10-27 | 1979-05-25 | Jeantet | Chromium plating anode - comprises lead alloy sheath into which is screw threaded metal of greater electrical conductivity |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0194321A1 (en) * | 1985-03-02 | 1986-09-17 | Bleiindustrie GmbH vorm. Jung + Lindig | Method for manufacturing lead anodes for zinc electrowinning, and lead anode produced thereby |
| WO2000042241A1 (en) * | 1999-01-13 | 2000-07-20 | Rsr Technologies, Inc. | Electrowinning anodes which rapidly produce a protective oxide coating |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2502188B1 (en) | 1985-11-22 |
| US4437965A (en) | 1984-03-20 |
| ATE15700T1 (en) | 1985-10-15 |
| FR2502188A1 (en) | 1982-09-24 |
| NO820866L (en) | 1982-09-20 |
| ES510520A0 (en) | 1983-02-01 |
| NO160088B (en) | 1988-11-28 |
| NO160088C (en) | 1989-03-08 |
| CA1169813A (en) | 1984-06-26 |
| ES8303549A1 (en) | 1983-02-01 |
| AU8162382A (en) | 1982-09-23 |
| AU552085B2 (en) | 1986-05-22 |
| JPS6318673B2 (en) | 1988-04-19 |
| DE3266279D1 (en) | 1985-10-24 |
| JPS57164997A (en) | 1982-10-09 |
| EP0060791B1 (en) | 1985-09-18 |
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