EP3460106A1

EP3460106A1 - Automatic auxiliary crane for maintaining an electrolysis installation

Info

Publication number: EP3460106A1
Application number: EP16891325.9A
Authority: EP
Inventors: Yves Lefevre
Original assignee: Individual
Current assignee: Zincobre Ingenieria SL
Priority date: 2016-02-25
Filing date: 2016-02-25
Publication date: 2019-03-27
Anticipated expiration: 2036-02-25
Also published as: MX2017000943A; RU2018133681A; WO2017144741A1; RU2018133681A3; EP3460106A4; ES2890827T3; EP3460106B1

Abstract

The maintenance method of an electrolysis installation comprises the stages of: - Identifying anomalies in the electrodes - Extracting, removing and replacing the anomalous electrodes moving them from the electrolytic tanks of the plant to the repair and replacement area. - Repositioning new electrodes the extraction, removal and replacement of the electrodes as well as the repositioning of new electrodes being carried out by means of an auxiliary crane comprising: - A Main Structure - A Longitudinal Translation System - A Main Lifting System - An Electrode Collection System The automatic auxiliary crane is used for maintenance in an electrolytic cell house, while the function of the Automatic Auxiliary Bridge Crane consists in the handling, inspection and maintenance of Electrodes, identifying anomalies in the electrodes located in the tanks.

Description

TECHNICAL FIELD AND OBJECT OF THE INVENTION

Electrolysis installations include electrolysis cells with pairs of electrodes, cathode and anode, and a tank with a solution in which the electrodes are submerged subjected to a continuous electrical voltage difference in order to produce electrolysis. Electrolysis enables obtaining for example zinc, copper, nickel, cadmium or cobalt deposited in the cathode from the salts of the solution.
Unlike electrolysis processes through electrorefining, in electrowinning the anode is substantially insoluble during electrolysis, providing the surface for producing the anodic oxidation reaction. These processes conventionally use a lead anode but other types of alloys such as titanium can be used.
Conventionally, electrodes are plate-shaped, arranged in rows in the tank such that the anodes and cathodes alternate and the cells are connected electrically in series. For the electrical connection between the electrodes during electrolysis, an electrode head holds each electrode. The electrode head comprises an electrode rod of an electrically conductive material, usually copper, and during electrolysis, the electrode head holds the electrode in the tank, vertically and in the longitudinal direction of the rod. Likewise, each rod is arranged abutting in electrical contact on equipotential rails, usually made of copper, that extend to the sides of the tank and perpendicularly to the electrodes. An electrode unit comprises an assembly of the electrode and the electrode head. The electrode units are positioned in the tank as close as possible to each other in order to increase the productivity of the installation, but avoiding the risk of a short circuit. Optionally, the electrode head comprises handling means for facilitating the extraction or the insertion of the electrode in the tank, or the transport thereof by means of a crane or a bridge crane of the installation, for example in the form of hooks or gripping lugs. Patent EP 1492906 describes this type of arrangement in an electrolysis installation.
The present invention relates to an automatic auxiliary crane for maintenance in an electrolytic cell house. The function of the Automatic Auxiliary Bridge Crane object of this invention for Handling, inspection and maintenance of Electrodes is that of identifying anomalies in the electrodes located in the tanks, such as increase in temperature, anomalous electrical contacts and faults in the morphology of the metal deposited in the electrodes, and enabling extraction, removal and replacement of the anomalous electrodes from the electrolytic tanks of the plant to the repair and replacement area. Once these electrodes have been removed, the load of the tank will be incomplete and this crane will be in charge of repositioning new electrodes, inserting them in their operating positions.
The invention is particularly applicable in a zinc electrolysis installation.

BACKGROUND OF THE INVENTION

The electrode units of the electrolysis system can present and/or cause failures during electrolysis, such as short circuits, electrical contacts of the electrolysis rods with the anomalous equipotential rails or faults in the metal deposited in the electrodes especially on the surface of the cathodes in electrowinning processes. These failures can damage the electrodes, the electrode units and the electrolysis installation, ultimately reducing the productivity of the installation.
In order to prevent or solve these failures it is necessary to carry out maintenance methods of the electrolysis installation. These methods comprise detecting a faulty electrode unit in an electrolysis tank of the installation, either relocating the faulty electrode unit (when the failure is due to faulty electrical positioning or contact of the electrode unit) or removing the faulty electrode unit from the tank leaving a gap in the tank (when the failure is caused by the electrode unit itself) and inserting a spare electrode unit into the gap (if applicable). In order to remove, reposition and insert the spare units, a crane or a bridge crane intended for the normal operation of the installation is conventionally used to remove the electrolysis product. An operator is in charge of handling the crane or bridge crane for these maintenance operations.
This known maintenance method has the drawback that the use of the crane or bridge crane for the procedure implies the stoppage of normal operations and less preventive maintenance time of the crane of the installation during the time needed to resolve the failures, since the crane or bridge crane is no longer available, consequently implying a reduction in the productivity of the installation.
Therefore, the present invention aims to provide a maintenance method that enables increasing the productivity of the installation.

DESCRIPTION OF THE INVENTION

The present invention provides a maintenance method of an electrolysis installation as set forth in claim 1 and explained below. Furthermore, the dependent claims reflect advantageous embodiments as disclosed below.
The invention comprises both the maintenance method of an electrolysis installation and the automatic auxiliary crane for maintenance of the electrolysis installation. The maintenance method of an electrolysis installation comprises the stages of:
Identifying anomalies in the electrodes located in the tanks, such as increase in temperature, anomalous electrical contacts and faults in the morphology of the metal deposited in the electrodes.
Extracting, removing and replacing the anomalous electrodes, moving them from the electrolytic tanks of the plant to the repair and replacement area.
Repositioning new electrodes by inserting them in their operating positions.
Unlike known state of the art, the maintenance method according to the invention comprises repositioning or removing the faulty electrode unit from the tank and/or inserting the spare electrode unit into the gap by means of an automatic auxiliary crane or bridge crane of the installation. Henceforth, the crane used conventionally for normal operations of the installation is called the main crane in order to distinguish it from the auxiliary crane.
This way, the use of the automatic auxiliary crane allows increasing productivity of the installation since it enables using the main crane for the normal operations of the installation while being able to proceed with the handling, repositioning or replacing of the faulty electrode units.
More specifically, the execution of the maintenance method of the installation enables eliminating any short circuits that may occur, inserting electrodes in the gaps of the tank due to the removal of those that were faulty, reducing the time needed to resolve the problems or anomalies that can occur frequently in the electrolysis installation, such as, for example, poor contact between the electrodes and the equipotential rail or a fault in the surface of the metal deposited in the electrode.
Advantageously, the stage of detecting the faulty electrode unit, repositioning or removing the same and/or inserting the spare electrode unit is carried out automatically, at least partially, that is, at least in some stages. This way, the productivity of the installation is further improved as the processing time for each stage can be reduced.
The invention anticipates the use of a detection system having at least one sensor for checking the status of the electrodes, such as electrode temperature sensors, electrode voltage drop sensors, display sensors of the metal deposited on the electrode and/or electrode weight sensors Thus, it is possible to detect whether the electrode units are faulty since short circuits in the installation or other anomalies during electrolysis can cause electrode temperature to rise, especially at the points of contact with the equipotential rails of the installation, irregularities in product deposition in the cathode detected by means of the morphology system of the deposited material or weight, and electrical voltage differences in the electrodes.
This way, it is possible to identify the anomalies in the electrodes located in the tank, such as increases in temperature, anomalous electrical contacts and faults in the morphology of the metal deposited in the electrodes and subsequently reposition, remove or replace the anomalous electrodes from the electrolysis tanks of the installation moving them to a repair or replacement area. During maintenance, faulty electrode units can be detected, which cannot be reinstalled in the production process. Once these electrode units have been discarded, the electrode unit of the electrolysis tank will be incomplete, leaving gaps that have to be filled. The auxiliary crane enables repositioning the new electrode units inserting them into their corresponding positions in the tank.
Advantageously, in order to detect the faulty electrode unit, the detection system comprises at least one sensor that remains static with respect to the electrolysis tank. This enables saving processing time with regard to the configuration in which the sensors move with respect to the tank or are fixed with respect thereto, although this last configuration, alternative or complementary, allows reducing the number of sensors in the installation.
For the automatic execution of the method, a control unit of the installation can be used, programmed to receive information from the detection system, process said information and command the auxiliary crane to reposition or remove the faulty electrode unit and/or insert the spare electrode unit.

BRIEF DESCRIPTION OF THE DRAWINGS

As a complement to the description provided herein, and for the purpose of helping to make the characteristics of the invention more readily understandable, in accordance with a preferred practical embodiment thereof, said description is accompanied by a series of figures constituting an integral part of the same, which by way of illustration and not limitation represent the following:

Figure 1 shows an upper perspective view of the auxiliary crane of the invention.
Figure 2 shows an elevation view of the auxiliary crane of the invention.
Figure 3 shows a profile view of the same auxiliary crane of the previous figures.
Figure 4 shows a detail of the auxiliary end truck.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

In one embodiment, the bridge crane of the auxiliary crane used in the maintenance method according to the invention for repositioning the faulty electrode unit (anode or cathode unit) in the tank or removing it from the tank leaving a gap therein, and/or inserting the spare electrode unit in the gap, comprises:
A Main Structure (1), made up of two box girders and two headwalls joined thereto, as well as a grid floor, gangway and railing for supporting and maintaining equipment.
A Longitudinal Translation System (2), made up of two motors and four wheels, that enable translation with respect to the electrolysis tanks of the installation, in a direction perpendicular to the longitudinal direction of the electrolysis rods on rails (8) abutting on rail beams (9)
A Main Lifting System (3) mainly made up of a lifting geared motor and two drums.
An Electrode Collection System (4), made up of
A Load-bearing structure of the electrode collection trolley (4a) and a centering and guiding System (4b), centering the crane and guiding the load-bearing structure of the electrode collection trolley (4a).
An Anti-Oscillation System
A Contact Temperature Checking System
An Electrode Voltage Checking System
A Morphological Analysis System of the deposited metal
An Auxiliary Lifting Mechanism (5)
A Feeding System (6)
An Electrical Installation, a Control System and an Air Conditioning and Cabinet Pressurization System (7).
The supports (9) and rails (8) of the main bridge corresponding to the bridge crane of the main crane can be used, thus minimizing the cost of the auxiliary bridge and thereby the operational costs of the maintenance method. Furthermore, the automatic auxiliary crane can accommodate auxiliary means for the operation thereof in order to carry out the method, such as a control unit or PLC for controlling the movements of the auxiliary bridge, electrical systems, refrigeration equipment and pressurization equipment. The automatic auxiliary bridge can also have access platforms for maintenance and supervision of said means. Access to these platforms from the transit areas of the electrolysis installation can be carried out by means of a ladder (10).
The full extent of travel of the auxiliary crane is limited in one direction by the stops of the rails, while in the other direction it is limited by the proximity of the main crane.
The drive of the wheels (11) of the headwalls for moving the auxiliary bridge can be carried out by means of an independent electric motor for each drive wheel that acts through an appropriate reducer and is commanded by means of a converter that makes it possible to use the appropriate translation and approximation speeds. The motors can also incorporate brakes, preferably electrically driven brakes. The displacement system of the described auxiliary bridge enables ensuring a positioning with respect to the electrolysis cells that is sufficiently precise to carry out the maintenance method according to the invention. In order to control the proper displacement of the different elements of the auxiliary crane, position detectors can be used on the parts of the crane with respect to which they move, such as markings. For collecting, extracting or inserting the electrode units, the electrode collection system (4) comprises:
A load-bearing structure of the electrode collection trolley (4a), and the centering and guiding system (4b). Both elements will have relative movements between them during the lifting and lowering strokes.
Once the Bridge has been placed in the approximate position thereof on the vertical of a cell, the following movements can be carried out:
Positioning the Bridge in the longitudinal direction of the plant.
Displacement inside the load-bearing structure of the electrode collection trolley (4a) up to the corresponding position of the Electrodes that are to be manipulated, and positioning the collection hooks in the opening or closing position, depending on the anodes or cathodes that are to be manipulated.
Lowering of both the load-bearing structure of the electrode collection trolley (4a) and the centering and guiding system (4b) until the latter fits into the positioning elements.
Lowering of the electrode collection trolley (4c) up to the position where it will engage or disengage the corresponding electrode bundle.
Lifting of the electrode collection trolley (4c) up to the position where it will abut with the Guiding Structure.
Lifting of both the electrode collection trolley (4c) and the centering and guiding system (4b) up to the starting position. During the lifting stroke thereof, the Electrode Collection Trolley (4c) will drag the Guiding Structure against which it had abutted.
In turn, the load-bearing structure of the electrode collection trolley (4a), which is in charge of handling the electrodes, comprises:
A frame that supports both the electrode collection trolley (4c) itself and the guide frame when it is lifted. This Frame incorporates four guide elements at the ends thereof that will enable the relative vertical movement of the Electrode Collection Trolley along the guides that the Guiding Structure will be equipped with.
Four pulleys through which the Main Lifting System will pass.
The electrode collection trolley (4c) in charge of handling the electrodes consisting of a frame on four wheels, two of which are motorized, which has four sets of opening and closing mechanisms of the electrode collection lugs.
A centering and guiding system (4b), comprising a mobile structure equipped with guide rails on which the Electrode Collection Trolley will slide.
The centering and guiding system (4b) is positioned on the upper part of the tank, ensuring the correct position of the Electrode Collection Trolley with respect to the electrodes for their handling.
The load-bearing structure of the electrode collection trolley (4a) will be in charge of the vertical movements of the centering and guiding system (4b) when dragging it in the vertical movements thereof, when abutting with it.
In the Main Structure of the automatic auxiliary crane object of this invention (1), two columns with guide rails will be located and on these, the Guiding Structure will abut and slide by means of mounted wheels. This way, the Guiding Structure will be referenced at all times with respect to the Main Structure.
Vertically: through the Main Lifting System
Horizontally: through the guiding in the columns provided for this purpose.
The electrode collection trolley (4c), as shown in detail in Figure 4, is configured for managing the electrode units, comprising a frame (17) on four wheels (18), two of which are motorized, which has opening and closing means (14) of the tilting gripping arms (21) with electrode collection lugs (15). These lugs have a coupling hole (16) to the gripping means (19) provided in the electrode heads (20), thus enabling management and handling thereof. The tilting gripping arms (21) can be built with two rotating arms that support the collection lugs (15), for example, driven in a coordinated manner by a single linear actuator that make up the opening and closing means (14). The use of two types of collection lugs (15) is anticipated, some for anodes and others for cathodes. In order to identify the presence of an electrode or a gap in the electrolysis tank, the electrode collection trolley (4c) can incorporate laser detectors, each corresponding to the position of a collection lug, which enable identifying the presence of the electrode in the support thereof on the electrolysis rod, identifying both the number of electrodes present and the correct polarity thereof.
In order to control the lowering of the load-bearing structure of the electrode collection trolley (4a) including the electrode collection trolley (4c) and the centering and guiding system toward the electrolysis cell, a suitable detector system can be incorporated.
Other means of protection, such as anti-oscillation, can also be incorporated to prevent the electrode units from oscillating or moving with respect to the collection trolley during the lifting and lowering motions.
The different elements of the auxiliary crane must be adequately protected against acid mist corrosion, especially found in zinc electrolysis installations, for example, by means of specific acid-proof paint.
The detection system for detecting faulty electrode units may include a detection system with an electrode temperature sensor system, an electrode voltage drop checking system, a system for analyzing the morphology of the metal deposited on the electrodes and/or a system for balancing or checking the weight of the electrodes.
The temperature sensor system may include as many sensors as electrodes in the tank.
The electrode voltage drop checking system includes voltage drop sensors, which can include as many voltage probes as the number of cathodes plus a probe, for measuring the voltage between the electrode rod and the electrolysis rail on which it abuts.
The system for analyzing the morphology of the metal can comprise fixed cameras intended to take pictures of the surface of the metal deposited on the electrode. These pictures can be analyzed manually by an operator in order to assess possible faults in the deposition or automatically by means of image analysis systems. The pictures have sufficient resolution to enable a global analysis of the electrode and the processing thereof so that they can serve as a basis for comparative and statistical analyses.
In order to carry out automatically the method according to the invention, a control unit can be used programmed to detect information from the sensors on the state of the electrode units, process said information and command the auxiliary crane through displacements of the crane and the components thereof, such as translation of the automatic auxiliary crane, lifting and lowering of the electrode collection system, the auxiliary hoist, the electrode collection trolley or the electrode collection lugs.
The control unit can also enable partially automatic or semi-automatic control, allowing one or several of the stages of the method to be carried out manually by an operator.

Claims

A MAINTENANCE METHOD OF AN ELECTROLYSIS INSTALLATION, characterized in that it comprises the stages of:
Identifying anomalies in the electrodes located in the tanks, such as increase in temperature, anomalous electrical contacts and faults in the morphology of the metal deposited in the electrodes.

Extracting, removing and replacing the anomalous electrodes moving them from the electrolytic tanks of the plant to the repair and replacement area.

Repositioning new electrodes by inserting them in their operating positions, the extraction, removal and replacement of the electrodes as well as the repositioning of new electrodes being carried out by means of an auxiliary crane.
MAINTENANCE METHOD OF AN ELECTROLYSIS INSTALLATION according to claim 1, characterized in that the stage of identifying anomalies in the electrodes, extracting, removing and replacing the electrodes as well as repositioning new electrodes is carried out automatically.
MAINTENANCE METHOD OF AN ELECTROLYSIS INSTALLATION according to one of claims 1 or 2, characterized in that it comprises detecting the faulty electrode unit by means of a detection system having at least one sensor selected from the group consisting of an electrode temperature sensor, an electrode voltage drop sensor, a system for analyzing the morphology of the metal deposited on the electrodes, an electrode weight sensor, and a combination of the above.
MAINTENANCE METHOD OF AN ELECTROLYSIS INSTALLATION according to claims 1 to 3, characterized in that it comprises the use of a control unit programmed to automatically receive information from the detection system, process said information and command the auxiliary crane to relocate or remove the faulty electrode unit and/or insert the spare electrode unit.
MAINTENANCE METHOD OF AN ELECTROLYSIS INSTALLATION according to claim 4, characterized in that in order to relocate or remove the faulty electrode unit and insert the spare electrode unit into the gap, the bridge crane of the auxiliary crane comprises an electrode unit collection system comprising an electrode unit collection trolley.
AN AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION, characterized in that it comprises:
A Main Structure (1), made up of two box girders and two headwalls joined thereto, as well as a grid floor, gangway and railing for supporting and maintaining equipment.

A Longitudinal Translation System (2), made up of two motors that actuate on wheels, enabling translation with respect to the electrolysis tanks of the installation, in a direction perpendicular to the longitudinal direction of the electrolysis rods on rails (8) abutting on rail beams (9)

A Main Lifting System (3) mainly made up of a lifting geared motor and two drums.

An Electrode Collection System (4),
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claim 6, characterized in that the electrode collection trolley (4c) handles the electrode units and comprises a frame (17) on four wheels (18), two of which are motorized, having opening and closing means (14) of the tilting gripping arms (21) with electrode collection lugs (15), these lugs being provided with a coupling hole (16) to the gripping means (19) provided in the electrode heads (20), thus enabling management and handling thereof.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claim 7, characterized in that the tilting gripping arms (21) can be built with two rotating arms that support the collection lugs (15), driven in a coordinated manner by a single linear actuator, that make up the opening and closing means (14).
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claims 6 to 8, characterized in that two types of collection lugs (15) are used, one for anodes and the other for cathodes.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claims 6 to 9, characterized in that the presence of an electrode or a gap in the electrolysis tank is identified by means of laser detectors, each corresponding to the position of a collection lug, which enable identifying the presence of an electrode in the support thereof on the electrolysis rod, identifying both the number of electrodes present and the correct polarity thereof, these elements being located in the electrode collection trolley (4c).
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claims 6 to 10, characterized in that in order to control the lowering of the electrode collection system (4) towards the electrolysis cell, it incorporates a detector system, further incorporating other protection means , such as anti-oscillation means, to prevent the electrode units from oscillating or moving with respect to the collection trolley during the lifting and lowering motions.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claims 6 to 11, characterized in that it further comprises:
- a detection system for detecting faulty electrode units with an electrode temperature sensor system,

- an electrode voltage drop checking system,

- a system for analyzing the metal deposited on the electrodes and/or

- a system for balancing or checking the weight of the electrodes.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claim 12, characterized in that the temperature sensor system may include as many sensors as electrodes in the electrolysis tank.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claim 12, characterized in that the electrode voltage drop checking system comprises voltage drop sensors, which can include as many voltage probes as the number of cathodes plus a probe, for measuring the voltage between the electrode rod and the electrolysis rail on which it abuts.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claim 12, characterized in that the system for analyzing the deposited metal comprises fixed cameras intended to take pictures of the surface of the metal deposited on the electrode, which are analyzed manually by an operator or automatically by means of image analysis systems in order to assess possible faults in the deposition.
AUTOMATIC AUXILIARY CRANE FOR MAINTENANCE OF AN ELECTROLYSIS INSTALLATION according to claims 6 to 15, characterized in that it has a control unit programmed to detect information from the sensors on the state of the electrode units, process said information and command the auxiliary crane through displacements of the crane and of each of the components of the auxiliary crane, such as the translation of the entire crane, that of the lifting of the electrode collection system (4) made up of the load-bearing structure of the electrode collection trolley (4a), the centering and guiding system (4b) the electrode collection trolley (4c), and the auxiliary lifting mechanism (5).