Acid mist-inhibiting sphere

Abstract

The present invention relates to an acid mist-inhibiting device for electrowinning and / or electrorefining plants, the device comprising a hollow spherical body and configured to float on the surface of an acid electrolyte in an electrolytic cell. An outer surface of the spherical body is provided with a plurality of cavities distributed over at least part of said outer surface.

Description

Acid mist inhibitor sphere in electrowinning and electrorefining plants. Descriptive Memorandum TECHNICAL FIELD OF THE INVENTION

[0001] The present invention falls within the field of hydrometallurgical processes that utilize electrolytic cells, particularly those for the electrowinning and / or electrorefining of metals that operate with acidic solutions. In these types of operations, the electrochemical action and the release of gases in the cell favor the formation of acid mist (electrolyte aerosols) that can rise from the surface of the electrolytic cell, disperse into the vessel environment, and generate undesirable effects, such as corrosive conditions, disruption of the operational environment, and potential impact on the health of operators.

[0002] In industrial practice, mitigation of this mist has been addressed through various strategies, including containment, extraction, and treatment measures, as well as solutions that act directly on the electrolyte surface. Among the latter, it is common to place floating objects, such as spheres, on the electrolytic cell to form a partial or total covering in one or more layers. However, in coverings formed by smooth-surfaced spheres, the ascent of gases and aerosols can persist through interstices and contact zones, facilitating the movement of gases between smooth surfaces, which can reduce the effectiveness of the surface barrier in inhibiting the mist.

[0003] In this technical context, the invention relates to an acid mist inhibitor device designed to be placed on the surface of the electrolyte, and to a surface coating system formed by a plurality of such devices. In particular, the invention falls within the area of ​​solutions that, while maintaining the ease of use of floating spheres, aim to improve mist inhibition by modifying the outer surface of the body, incorporating a plurality of cavities (preferably hemispherical) intended to promote local mist retention, condensation, and the return of the electrolyte to the solution, while also mechanically hindering the rise of the mist from the surface of the electrolytic cell. BACKGROUND

[0004] In the processes of electrowinning and electrorefining of copper, zinc or other metal cathodes, specifically in electrolytic cells composed of anodes and cathodes immersed in an electrolytic solution rich in sulfates of the metal to be deposited, a representative overall reaction occurs as follows: CuSO4(acu) + H2O(aq) - Cu°(s) + EbSC ac) + 02(g)

[0005] This reaction generates large quantities of oxygen bubbles at the anode and, to a lesser extent, hydrogen bubbles at the cathode. Specifically, the oxygen bubbles rise to the surface of the electrolyte and, upon breaking, carry microdroplets of the electrolyte, forming an "acid mist" that can be a serious contaminant for operators and the environment of the electrowinning facility. In fact, solutions are known that address this same phenomenon of mist generation by bubble rupture on the electrolyte surface. These solutions propose encapsulating the area where the mist is generated using electrode covers with hydrophilic membranes that trap the droplets while allowing gases to pass through.

[0006] To mitigate the impact of acid mist, a common practice is to place two or more layers of plastic spheres on the electrolyte surface. These spheres are hollow inside and smooth on the outside, forming a mechanical barrier that partially obstructs the mist's ascent. However, because the surface of these spheres is completely smooth, gases and vapors can rise relatively easily between smooth surfaces, making mist reduction insufficient under certain operating conditions.

[0007] Furthermore, there is precedent for covering liquid surfaces in open ponds using floating bodies. For example, US patent 3,401,818 describes the use of a plurality of floating spheres to substantially cover the liquid surface, aiming to reduce evaporation losses and other problems associated with open ponds. It even notes that the spheres can be oriented to cover a high percentage of the surface. The same document mentions German patent DE 1 060 323, which proposes hollow floating bodies with a foamed structure incorporating cavities, raised areas, and channel-like depressions. However, it indicates that such bodies have disadvantages due to their irregular shape, resulting in significant losses (e.g., from evaporation).US 3,401,818 also teaches that an additional problem can be the rotation of floating bodies on the surface, proposing a circumferential bead to reduce this rotation and improve performance as a cover.

[0008] Additionally, as noted, US 6,120,658 specifically addresses “electrolyte mist” in electrowinning by using an electrode cover that creates a sealed chamber around the area where bubbles burst. The cover uses hydrophilic fibers to trap droplets and drain them back into the electrolyte, while allowing gases to pass through to prevent overpressure. While these solutions may be effective in their own right, their implementation relies on electrode-associated covers rather than a modular floating system positioned on the electrolyte surface, and they do not, by themselves, resolve the practical limitation described for smooth spheres stacked in layers (i.e., the residual rise of vapors and mist between smooth surfaces).

[0009] Consequently, there remains a need for a simple alternative, compatible with the use of floating sphere layers, that would further reduce the acid mist rising from the electrolyte surface. To this end, it is proposed to modify the sphere's surface—maintaining its plastic and preferably hollow nature—so that it is not smooth, but rather comprises, across all or substantially all of its surface, a plurality of cavities (preferably hemispherical). These cavities are designed to trap mist, promote vapor condensation, and facilitate the return of condensate to the electrolyte, while also hindering the upward passage of mist through both condensation and the geometry of the cavities themselves. GENERAL DESCRIPTION OF THE INVENTION

[0010] As previously mentioned, in electrowinning and / or electrorefining operations using acidic electrolytes, the rupture of bubbles on the electrolytic cell surface generates and projects microdroplets of electrolyte, creating an acid mist that tends to rise and disperse into the vessel environment. Mitigation measures are known that act on the electrolyte surface using layers of floating materials, such as smooth plastic spheres; however, these smooth-surfaced spheres can allow residual gas and aerosol ascent through interstices and contact areas, resulting in insufficient inhibition under certain operating conditions. There are also alternatives that encapsulate or cover specific areas (for example, those associated with electrodes), which may involve additional structures and a more complex implementation for covering large surfaces of the electrolytic cell.

[0011] In this context, the technical problem addressed by the invention is to provide a simple and easily deployable surface solution, compatible with the operation of electrolytic cells, which allows for a greater inhibition of the rise and dispersion of acid mist from the surface of the electrolyte, while also favoring the return of the electrolyte carried towards the electrolytic cell.

[0012] Accordingly, one objective of the invention is to provide an acid mist inhibitor device that, while maintaining the simplicity of a spherical floating body, incorporates a surface configuration that increases the local capture of mist and / or vapor, promotes its condensation, and facilitates the drainage / return of the electrolyte to the electrolytic cell. Another objective is to provide an acid mist inhibitor system for electrowinning and / or electrorefining cells, based on the surface arrangement of a plurality of such devices.

[0013] The invention addresses this problem and objectives by means of a device comprising a preferably spherical body, preferably made of plastic, and preferably hollow, configured to float on the surface of the electrolyte. Unlike smooth spheres used in the art, the body has a plurality of cavities on its outer surface distributed over at least part of the outer surface; in preferred embodiments, these cavities are arranged over all or substantially all of the outer surface. In a preferred embodiment, the cavities are hemispherical. In alternative embodiments, the cavities may have other geometries, such as triangular, cubic, conical, cylindrical, multi-shaped cavities, or combinations thereof.

[0014] Without being limited by any particular theory, the presence of this plurality of cavities is considered to contribute to: (i) locally trapping some of the mist and / or microdroplets projected from the electrolyte surface; (ii) promoting the condensation of vapors and aerosols on the internal surfaces of the cavities; and (iii) allowing the collected liquid to return to the electrolyte by gravity. Additionally, the cavity configuration provides an improved mechanical barrier compared to smooth surfaces, hindering the ascent of mist between the surfaces of the floating bodies.

[0015] In a preferred embodiment, the invention comprises an acid mist inhibitor system including a plurality of the described devices, arranged floating on the electrolyte surface of a cell, so as to form at least one surface coverage layer over at least part of said electrolyte surface; in one implementation, the plurality of devices covers all or substantially all of the electrolyte surface. In typical implementations, two or more layers may be arranged to increase the degree of coverage and the trapping / condensation action associated with the cavities, thus helping to inhibit the rise and dispersion of acid mist during operation.

[0016] The device can be manufactured by molding, for example in such a way that the cavities are defined directly on the outer surface during the manufacturing process, without this implying any limitation with respect to constructive variants compatible with the present invention. BRIEF DESCRIPTION OF THE FIGURES

[0017] The figures described below are included as part of the present invention, which are illustrative in nature and should not be interpreted as limiting the scope of the claimed subject matter.

[0018] Figure 1 shows an isometric view of a spherical acid mist inhibitor device, comprising a preferably spherical body (1) whose outer surface comprises a plurality of hemispherical cavities (2), according to a preferred embodiment of the invention.

[0019] Figure 2 shows a second isometric view of the spherical device of Figure 1, in which the body (1) is represented in a darker tone to contrast and more clearly appreciate the plurality of hemispherical cavities (2), according to a preferred embodiment of the invention.

[0020] Figure 3 shows a cross-sectional view of the spherical device of Figures 1 and 2, in which it can be seen that the spherical body (1) is hollow inside, maintaining on its outer surface the plurality of cavities (2), according to a preferred embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Figure 1 shows an isometric view of the device, which comprises a body (1), preferably spherical in shape, whose external surface comprises a plurality of semi-spherical cavities (2).

[0022] The invention is then described in detail with reference to Figures 1 to 3. These figures and the associated description are illustrative and should not be interpreted as limiting the scope of protection sought, which is determined by the claims.

[0023] As shown in Figures 1 and 2, in a preferred embodiment the invention provides an acid mist inhibitor device intended to be placed on the surface of an acid electrolyte in an electrowinning and / or electrorefining cell. The device comprises a body (1), preferably spherical in shape and preferably made of plastic. As shown in Figure 3, this body (1) is hollow, a feature that facilitates its floating position on the surface of the electrolyte.

[0024] A central aspect of the invention is that the outer surface of the body (1) is not smooth, but comprises a plurality of cavities (2) distributed over at least part of said outer surface; in preferred embodiments, the plurality of cavities (2) are arranged over all or substantially all of the outer surface. In one preferred embodiment, such cavities (2) are hemispherical, as shown in Figures 1 to 3. In alternative embodiments, the cavities (2) may have other geometries, such as triangular, cubic, conical, cylindrical, multi-shaped cavities, or combinations thereof, while maintaining the general concept of providing multiple depressions or concavities on the outer surface of the body (1).The cavities (2), including hemispherical cavities, can be arranged uniformly on the outer surface of the body (1), or randomly, or according to mixed distribution patterns by zones, maintaining in all cases the presence of a plurality of cavities on the outer surface.

[0025] In industrial applications, smooth, floating plastic spheres have been used as a surface barrier. However, lacking capture microgeometries, these smooth surfaces tend to allow some gases, vapors, and aerosols to rise along relatively direct paths between contact zones and interstices, resulting in limited mist reduction under certain operating conditions.In contrast, the plurality of cavities (2) of the present invention introduces a surface configuration that, in operational terms, favors one or more of the following actions, without being limited by a particular theory: (i) local trapping of mist and microdroplets, by providing multiple zones where the aerosol can be temporarily retained; (ii) promotion of condensation, by increasing the effective contact surface and generating microzones more protected from the upward flow; (iii) return of the electrolyte to the electrolytic cell, as the collected and coalesced liquid can return by gravity to the electrolyte; and (iv) an improved geometric barrier compared to smooth surfaces, hindering the direct ascent of the aerosol and promoting less direct trajectories with greater interaction with capture surfaces.Thus, while maintaining the simplicity of a spherical floating body, the invention provides a functional improvement based on a change in the shape of the outer surface, compatible with layered deployment over extensive electrolyte surfaces.

[0026] In a preferred embodiment, the invention further comprises an acid mist inhibitor system that includes a plurality of the devices described above. These devices are arranged floating on the surface of the electrolyte, forming at least one surface coverage layer over at least part of said surface; in one implementation, the plurality of devices covers all or substantially all of the electrolyte surface. In the layer(s) formed, the devices may be in at least partial contact with each other, or separated by gaps, while maintaining the mist inhibition effect. In typical applications, two or more layers may be arranged to increase the degree of coverage, reducing gaps and increasing the number of cavities (2) available for entrapment and condensation.The resulting system acts as a modular, easily implemented covering, as the devices can be distributed directly onto the electrolytic cell, adapting to its geometry and surface area without requiring complex structural modifications associated with fixed components. Furthermore, being independent elements, the devices can be removed, replaced, and redistributed according to operational needs, maintaining the continuity of the mist mitigation system.

[0027] Regarding its manufacture, the device can be manufactured by molding, such that the body (1) and the cavities (2) are formed during the process. In a preferred embodiment, the cavities (2) are defined directly by the mold design, resulting in an outer surface with a plurality of cavities without requiring additional operations. This is understood as a preferred embodiment and does not limit other constructive variants compatible with the invention.

[0028] Finally, it should be understood that the preceding description and accompanying figures are presented solely for illustrative purposes of preferred embodiments, and that various modifications, variations and technical equivalents may be implemented by a person skilled in the art without departing from the concept of the invention, the scope of protection sought being determined by the accompanying claims.

Claims

CLAIMS 1. An acid mist inhibitor device for electrowinning and / or electrorefining plants, CHARACTERIZED in that it comprises a hollow spherical body configured to float on the surface of an acid electrolyte in an electrolytic cell, wherein an outer surface of the spherical body is provided with a plurality of cavities distributed over at least part of said outer surface.

2. The device according to claim 1, CHARACTERIZED in that the plurality of cavities is distributed over the entire outer surface of the spherical body.

3. The device according to any of claims 1 to 2, CHARACTERIZED in that the plurality of hemispherical cavities is uniformly distributed over said outer surface.

4. The device according to any of claims 1 to 2, CHARACTERIZED in that the plurality of hemispherical cavities is randomly distributed over said outer surface.

5. The device according to any of claims 1 to 4, CHARACTERIZED in that the spherical body is made of a plastic material.

6. The device according to any of claims 1 to 5, CHARACTERIZED in that the plurality of cavities corresponds to hemispherical cavities.

7. The device according to any of claims 1 to 5, CHARACTERIZED in that the plurality of cavities corresponds to cavities of geometry selected from hemispherical, triangular, cubic, conical, cylindrical, multiform, or combinations thereof 8. The device according to any of claims 1 to 7, CHARACTERIZED in that the device is manufactured by molding, the cavities on the outer surface being defined by the design of a mold.

9. An acid mist inhibitor system for electrowinning and / or electrorefining plants, CHARACTERIZED in that it comprises a plurality of devices according to any of claims 1 to 8, arranged floating on the surface of an acid electrolyte contained in an electrolytic cell, forming at least one layer on at least part of said surface.

10. The system according to claim 9, CHARACTERIZED in that the plurality of devices forms two or more layers on the surface of the electrolyte.

11. The system according to any of claims 9 to 10, CHARACTERIZED in that the plurality of devices is arranged in such a way as to cover at least part of the surface of the electrolyte.

12. The system according to any of claims 9 to 10, CHARACTERIZED in that the plurality of devices is arranged in such a way as to cover the entire surface of the electrolyte.

13. The system according to any of claims 9 to 12, CHARACTERIZED in that the devices are in at least partial contact with each other in the layer formed on the surface of the electrolyte.

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