KR20170038880A - Cell for metal electrowinning - Google Patents

Abstract

The present invention relates to an electrolytic apparatus for electrolytic collection of a non-ferrous metal containing a plurality of inserted basic cells, each basic cell having a device suitable for detecting current distribution abnormality to each of the anodes.

Description

CELL FOR METAL ELECTROWINING [0002]

The present invention relates to an electrolytic apparatus comprising a plurality of basic cells suitable for electrolytic collection of metals, in particular for electrolysis of copper and other non-ferrous metals originating from an ionic solution, and an electrolytic harvesting facility equipped with such electrolytic apparatus.

Electrolytic facilities for non-ferrous metal deposition, also known as electrolytic extraction and smelting facilities, respectively, such as facilities for electrolytic extraction and refining of metals, generally comprise a plurality of bases, each containing an anode and a cathode Lt; RTI ID = 0.0 > cells. ≪ / RTI >

In the electrolytic apparatuses for the above-mentioned facilities, the anodes and cathodes are disposed in substantially parallel to each other at staggered positions and in the electrolytic cell. Each electrode is mechanically and electrically connected to a hanger bar and is supplied with electricity through the contact of its respective hanger bar and bus-bar. In an electrolytic device, the same bus-bars are shared between electrodes of the same polarity and are connected in parallel with one another.

In the case of facilities for the production of non-ferrous metals, for example copper, cobalt, zinc or nickel, the metal produced by the electrochemical reaction is precipitated by the action of a current flow on the cathode of each basic cell. The precipitated products are harvested at regular intervals of several days, generally when extracting the cathodes from the associated electrolytic apparatus. Precipitation of the metal on the cathode surface can take place in a non-uniform manner and the dendrites or dendritic formations that grow towards the opposing anode at an increasing rate under the influence of current flow until the electrical short is started can also generate local precipitates, also known as dendritic formations. In this case, an increase in the temperature of the anode surface corresponding to contact with the dendritic formation can cause serious damage; In some cases, the dendritic formations are locally bonded to the anode surface, thereby interfering with subsequent cathode extraction and consequently with the entire metal harvesting operation.

The above-mentioned problems associated with the formation of resin assumptions are particularly relevant to the modern concept of anodes made of titanium substrates, such as mesh or expanded sheets, provided with a coating of catalytic material. Although these anodes are preferred due to increased efficiency compared to conventional lead anodes, short circuit conditions can often cause extensive and irreparable damage. This problem is still unsolved for the advanced anode type disclosed in patent application WO2013060786 in which the catalyst-coated titanium mesh is inserted into an envelope composed of a permeable material, such as a separator of a porous polymer or an ion-exchange membrane. Damage to the anodes involves additional damage associated with higher facility maintenance costs, loss of metal products, and possibly forcible closure of the facility.

It would therefore be desirable to provide a form that protects the anodes of the basic cells of the electrolytic device in the case of growth of the dendritic formations. It is also desirable to quickly identify and report on the individual anodes of the electrolytic device where growth of one or more dendritic formations constitutes a potential threat. Since metal electrolytic harvesting facilities are hazardous environments due to the presence of acid fog which may be in the vicinity of high temperatures and electrolysis devices, the detection and in particular the signaling of individual anodes affected by dendritic formations is also subject to facility maintenance personnel So that the residence time in the electrolysis chamber can be reduced.

Various aspects of the invention are set forth in the appended claims.

According to one aspect, the present invention relates to an electrolytic apparatus for electrolytic collection of a metal consisting of a plurality of basic cells, each cell comprising an anode and a cathode via an electrically conductive porous screen, And the cathode is suitable for precipitation of the metal from the electrolytic bath. The cell further includes an electrically conductive anode hanger bar electrically and mechanically connected to the anode, and an electrically conductive cathode hanger bar electrically and mechanically connected to the cathode. Each base cell also includes a device suitable for direct or indirect detection of current flowing across the corresponding anode hanger bar. The electrolytic device also has an anode bus-bar electrically connected to the anode hanger bars of each cell, and a cathode bus-bar electrically connected to the cathode hanger bars of each cell. The electrolytic device may also include a cathode balance bar disposed in parallel and proximity to the anode bus-bar.

The conductive porous screen interposed between the anode and the cathode of the basic cell is of a structure that can exhibit a different degree of density and permit passage of the electrolyte solution without interfering with the ion conduction between the cathode and the anode.

By performing electrolysis in an electrolytic device design as described above, the resin assumptions that may be formed in one or more cathodes of the primary cells come into contact with opposing porous screens before reaching the back of the anode surface, Or, in any event, slow down. It has been observed that when the dendritic form is in contact with the porous screen, if the screen has a little electrical conductivity, some of the metal produced in the cell directly deposits on the screen as a coating. In this case, the assembly consisting of the cathode, the resinous and the porous screen additionally performs the function of a new cathode of the basic cell, by electrical connection existing between these elements, and is further placed closer to the anode than the original one . In this situation, the low resistance drop of the electrolyte associated with the reduced gap between the new cathode and the anode causes an increase in current flowing across the associated anode hanger bar. It was found that the degree of the current increase can be used as an index of the growth of the resin.

In one embodiment, direct or indirect detection of the current flowing through each anode hanger bar can be made at the bar itself, or at elements electrically connected thereto, by means of a detection device capable of measuring voltage or temperature changes.

In one embodiment, the measurement of the voltage change is made through the connection of the sensing device to the cathode hanger bar on the other side to the associated anode bus-bar on one side by an electrically conductive and optionally flexible pressure contact. This configuration can provide the advantage of avoiding electrical connections fixed to the anode hanger bar and facilitates subsequent maintenance work on the cell.

In another embodiment, the measurement of the voltage change is made by connecting the detection device to the anode hanger bar corresponding to two points located a certain distance along the long axis.

In one embodiment, the measurement of the temperature change may be made by a thermosensitive device, for example a thermocouple. This measurement may be made, for example, with a thermally sensitive device installed in the respective anode hanger bar, preferably corresponding to its terminal portion, or alternatively in the anode bus-bar corresponding to each point of contact with the anode hanger bars . The thermosensitive device may be provided with an anti-chemical lining suitable for protecting and / or increasing the insulation from the surrounding environment.

In another embodiment, the measurement of the temperature change can be made through the use of a thermal response coating that changes their color whenever the temperature exceeds a predetermined threshold. This paint is painted on the anode bus-bar corresponding to the point of contact with the anode hanger bar or the anode hanger bar. This embodiment immediately clarifies the potentially important situations determined by the growth of the dendritic formations to the personnel working inside the electrochemical plant, and the electrolysis apparatus in which these situations arise and also the rapid identification of the anodes or the anodes in such electrolytic apparatus Lt; RTI ID = 0.0 > and / or < / RTI >

 In one embodiment, each detection device may be coupled to its own microprocessor configured for comparison between measurements by the device and a predetermined reference range; If the measurements are not within the reference range, the microprocessor may activate one or more signaling systems operating sequentially or simultaneously. The microprocessor and / or signal originating system may be turned off during the cathode extraction operation, for example, taking product harvest into account. The microprocessor may be integrated with the signaling system and / or the detection device within a single device.

In one embodiment, the microprocessor is operated by a process electrical voltage to avoid the use of batteries requiring periodic replacement. In particular, the microprocessor can be directly connected to the anode bus-bar and cathode equilibrium bar when the electrolytic device is equipped with it. If the electrolytic device does not include a cathode equilibrium bar and wishes to avoid the fixed lines that interfere with facility operations, the microprocessor, instructed to monitor a particular anode hanger bar, is preferably connected to the anode bus-bar and the adjacent cathode Can be connected to the hanger bar.

In one embodiment, the microprocessor operates at least one signal emitting system consisting of a light emitting diode that can be coupled to the optical fiber, either directly or through an optical coupling device. Optionally, the fiber optic, enclosed in a polymeric material, allows identification of the facility personnel by allowing transmission of the optical signal to the terminal portions of each anode hanger bar or, even more preferably, to the exterior of the electrolytic device And to quickly find associated anodes or anodes and electrolysis devices that exhibit direct or indirect current values outside the range of predetermined values.

In one embodiment, the porous screen may be made of a carbon fabric of suitable thickness. In yet another embodiment, the porous screen may comprise a mesh or perforated sheet made of a corrosion resistant metal, such as titanium, provided with a coating that is catalytically inactive for an oxygen release reaction. In one embodiment, the catalytically inactive coating may be based on tin, tantalum, niobium or titanium, for example in the form of an oxide. In one embodiment, the anodes are obtained from titanium meshes or expanded sheets coated with a catalytic material. In yet another embodiment, the catalyst coated titanium mesh is inserted into an envelope composed of a permeable separator, for example a porous sheet of polymeric material or a cation exchange membrane, secured to a frame and mounted on top of a demister.

The optimal porous screen-to-anode surface gap depends on the process characteristics and the overall size of the facility. In the facilities used to verify the present invention, the best performance was obtained in cells using porous screens located at 1-20 mm distance from the anodes and cathodes spaced 25-100 mm apart and opposite anodes.

In another aspect, the present invention is directed to an anode, a porous screen, an anode hanger bar mechanically and electrically connected to the anode, and an apparatus suitable for direct or indirect detection of current flowing across the anode hanger bar, To an anode element for basic cells of electrolytic devices for metal electrolytic collection. Apparatus suitable for direct or indirect detection of current can be made as described above and compares the values detected with a predetermined range of values and activates one or more alarm signals when the detected value is not within a predetermined range And may be selectively coupled to a suitable microprocessor. The alert signal may be auditory, visual, electromagnetic or other types, and may consist of a combination of multiple signals.

In another aspect, the present invention relates to a basic cell of an electrolytic apparatus for metal electrolytic collection,

- An anode having a catalyst surface for oxygen release reaction;

- A cathode adapted to deposit a metal from an electrolytic cell arranged parallel to the anode;

- A porous screen interposed between the anode and the cathode;

- An electrically conductive anode hanger bar integral with the anode and electrically connected to the anode;

- An apparatus suitable for direct or indirect detection of current flowing across the anode hanger bar;

- And an anode bus-bar electrically conductive and electrically connected to the anode hanger bar.

In another aspect, the present invention is directed to a method for obtaining copper from a solution comprising a first copper and / or a second copper ion, comprising the step of electrolyzing the solution in an electrolysis apparatus as described above.

Certain implementations illustrating the present invention will now be described with reference to the accompanying drawings, which have a sole purpose of illustrating the interconnection of different elements with respect to the particular implementations of the present invention; In particular, the drawings are not necessarily drawn to scale.

Fig. 1 schematically shows a basic cell of an electrolytic apparatus for electrolytic metal electrolysis according to an embodiment of the present invention.
2 schematically shows a possible system for indicating the growth of dendritic formations in a basic cell of an electrolytic apparatus for electrolysis for metal electrolysis according to another embodiment of the present invention.

1 schematically shows a basic cell of an electrolytic apparatus for metal electrolytic collection, which comprises a cathode 200 suitable for metal precipitation from an anode 100 and an electrolytic cell aligned parallel to the anode, a cathode 200, An anode hanger bar 400 integral with the anode and electrically connected to the anode, a cathode hanger bar 450, a direct or indirect detection of the current flowing across the anode hanger bar 400, And an electrically conductive anode bus-bar 600 electrically connected to the anode hanger bar 400. As shown in FIG. Apparatus 500 suitable for direct or indirect detection of current may be coupled to microprocessor 700 configured to compare the amount detected by apparatus 500 with a predetermined range of values. The microprocessor 700 is coupled to a signaling system 800 that is activated when the detection provides a value outside the reference range.

Figure 2 shows an apparatus 500 that is suitable for direct or indirect detection of an electrical current and is connected to the microprocessor 700 for comparing the detection to a predetermined range of values. The microprocessor 700 is configured to operate the signaling system 800 when the detection provides a value outside the reference range. The signal transmission system 800 may comprise a light emitting diode 801 that emits an optical signal in the case of operation by the microprocessor 700. The signal of the diode 801 is transmitted by the optical fiber 803, which is selectively coupled to the diode 801 through the optical coupling system 802.

The end of the fiber 803 from which the optical signal is output is located at a suitable point so that it is easily identified by the staff 900 working at the facility.

The foregoing description is not intended to limit the invention, and the invention may be used in accordance with other embodiments without departing from the scope of the invention, the scope of which is defined solely by the appended claims.

Throughout the description and claims of this application, variations such as "comprises" and "comprising" are not intended to exclude the presence of other elements, components, or additional processing steps.

Discussions of documents, acts, materials, devices, articles, and the like are included herein solely for the purpose of providing context for the present invention. None or all of these statements are presented or represented as part of the prior art, or prior knowledge of the claims of each of the present application, which are conventional knowledge in the field relating to the present invention.

Claims (16)

A basic cell of an electrolytic apparatus for metal electrolytic collection, comprising:
An anode having a catalyst surface for oxygen release reaction;
A cathode adapted for precipitation of the metal from an electrolytic cell arranged parallel to said anode;
An electrically conductive porous screen interposed between the anode and the cathode;
An electrically conductive anode hanger bar integral with the anode and electrically connected to the anode;
An apparatus suitable for direct or indirect detection of current flowing across the anode hanger bar;
An anode bus-bar electrically conductive and electrically connected to the anode hanger bar. The method according to claim 1,
Wherein the direct or indirect detection of the current comprises an evaluation of a selected physical quantity between voltage and temperature. 3. The method of claim 2,
Wherein the evaluation of the physical quantity is a measurement of temperature by use of a thermochromic paint or a thermosensitive device. The method of claim 3,
Wherein the thermosensitive device is a thermocouple, the basic cell of the electrolytic apparatus for metal electrolytic collection. The method according to claim 3 or 4,
Wherein the temperature measurement is performed on the anode hanger bar in the vicinity of the electrical connection of the anode bus-bar. The method according to claim 3 or 4,
Wherein the temperature measurement is performed on the anode busbar in the vicinity of the anode hanger bar. The method according to claim 1,
Wherein the microprocessor is further configured to compare the detection of the current with a predetermined reference range, and wherein the at least one signal transmission system is configured to detect the presence of the at least one signal transmission system, And is configured to operate whenever it provides a value outside the reference range. 8. The method of claim 7,
An electrically conductive cathode hanger bar integral with the cathode and electrically connected to the cathode;
- a basic cell of an electrolytic apparatus for electrolysis of metal electrolytic, further comprising a cathode equilibrium bar. 9. The method of claim 8,
Wherein the power supply of the microprocessor is provided by a process voltage. 10. The method of claim 9,
And said power supply is obtained by being connected to said anode bus-bar and said cathode equilibrium bar. 10. The method of claim 9,
Wherein the electric power supply is obtained by connecting to the anode bar and pressure-contacting the cathode hanger bar. 12. The method according to any one of claims 7 to 11,
Wherein the signal emitting system comprises a light emitting diode operated by the microprocessor. 13. The method of claim 12,
Wherein the light emitting diode is connected to an optical fiber. An electrolytic apparatus for the primary extraction of metal from an electrolytic cell, comprising: a stack of cells according to any one of claims 1 to 13 interconnected electrically. A method of obtaining copper from a solution comprising cuprous and / or cupric ions, comprising electrolyzing said solution in an electrolytic apparatus according to claim 14. An anode device for a metal electrolytic collection cell,
An anode having at least one catalytic surface for an oxygen releasing reaction, at least one porous screen, an anode hanger bar mechanically and electrically connected to the anode, and a device suitable for direct or indirect detection of current flowing across the anode hanger bar Anode device for metal electrolytic collection cells.

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