US20070284243A1

US20070284243A1 - Modular system for improving electro-metallurgical processes

Info

Publication number: US20070284243A1
Application number: US11/802,672
Authority: US
Inventors: Pedro Aylwin; Andres Cardeon; Manuel Umana
Original assignee: New Tech Copper SA
Current assignee: New Tech Copper SA
Priority date: 2006-05-30
Filing date: 2007-05-24
Publication date: 2007-12-13
Also published as: CA2586149A1; AU2007201708B2; PE20071262A1; CA2586149C; ZA200704426B; AU2007201708A1

Abstract

A modular system for improving electro-metallurgical processes comprising a nucleus formed by upper and lower rectangular frames, the nucleus. At least one cathode guide is attached to at least one of longitudinal beams. The at least one cathode guide is operable to keep positive ions from reaching border or edge of the cathode. At least one anode guide is provided.

Description

BACKGROUND

The industrial obtainment of high purity metals such as copper, nickel, zinc and others is carried out mostly by electrolytic deposits from acid or alkaline water solutions of the respective metals. Whether the metal is obtained from its solutions using insoluble anodes or by dissolving anodes of the metal itself, stainless steel cathodes, also known as permanent cathodes, are vastly used through out these industries.
Although the use of permanent cathodes has solved some processing issues; because the metal is also deposited on their vertical and lower horizontal edges the dislodging of the metal deposited presents severe difficulties. Moreover, since this step is done mechanically by introducing knives between the metal deposited and the stainless steel plate, irregularities on the edges and scratches and deformations on the faces of the cathodes occur. All this means that the stainless steel cathodes must be straightened, re-polished and on occasion replaced with the resulting associated costs.
To avoid the electro-deposition of the metal on the edges of the cathodes, some have resorted to covering them with plastic strips to keep them from having contact with the electrolyte. Although the strips are pressure locked onto the sides of the cathodes, the fact that the electrolysis is carried out at temperatures of about 50° Celsius causes the strips to expand and deform. These deformations result in an imperfect seal of the borders of the cathodes that allow large nodules of metal to be electro-deposited on the exposed zones. These nodules add another degree of difficulty to the removal of the plastic strips as well as to the metal deposited. When this occur the metal nodules have to be hammered off to be removed. During this operation the lower ends of the strips are destroyed, making their replacement necessary with the resulting associated costs.
Attempts have also been made to cover the sides of the cathodes that are submerged in electrolyte with a half-frame, shaped like a letter U, of the same metal that is being obtained, so as to form a screen that keeps the deposits from forming on the borders. Although it is true that this screen reduces the amount deposited, it does not solve the entire problem.
In an attempt to resolve this weakness, an effort was made to connect the half-frame to an external source of radio frequency, which would solve the problem. Nevertheless, the fact that the half-frame is made of metal and that it is connected to the same potential of the cathode, causes the metal to deposit also on the outside of the half-frame, increasing its thickness, and forcing its reconditioning or replacement after a few production cycles.
In addition to the problems mentioned, because the anodes and cathodes are suspended freely within the cell, when the anodes and cathodes oscillate occasional short-circuits are produced that diminish the current efficiency of the operation and force the re-processing of the damaged products and the repairing or replacement of the anodes and cathodes.
All these problems increase production costs and lower the quality of the cathodes produced having detrimental business consequences.
Recently, a holding structure of an insulating material was designed, to which energizable slots were attached. These slots serve as vertical guides for the sides of the cathodes so they have been named “cathode guides”. These slots can be energized with a DC current and a high frequency voltage potential to control the cathode peripheral deposit and eliminate the use of plastic strips to solve this problem.
Another problem associated to the operation in the electro-metallurgical processes is the formation of acid fog that cause health problems among the workers and damages to the structures of buildings, equipment and instruments. Efforts have been made to try and solve this problem by either inhibiting its formation by the introduction of radio frequencies or preventing its propagation outside the cell by the application of air-curtains to condense the vapors present in the fog and return the condensates to the electrolyte, the use of extraction hoods, surfactants to reduce the surface tension of the solution and minimize electrolyte pulling, plastic spheres to reduce the electrolyte pulling.

SUMMARY

To overcome some of the problems mentioned above and to realize some of the discussed advantages, there is provided a modular system for improving electro-metallurgical processes comprising a nucleus formed by upper and lower rectangular frames, the nucleus. At least one cathode guide is attached to at least one of longitudinal beams. The at least one cathode guide is operable to keep positive ions from reaching border or edge of the cathode. At least one anode guide is provided.
Another aspect of the disclosed teachings is a use of the system described above in a treatment of liquid waste or electroplating.

DESCRIPTION OF THE DRAWINGS

The above objectives and advantages of the present invention will become more apparent by describing in detail embodiments thereof with reference to the attached drawings in which:
FIG. 01.a is an isometric view of a subassembly of two cathode guide profiles according to an exemplary embodiment of the present invention.
FIG. 01 shows an enlarged isometric view of the upper part of a subassembly of two cathode guide profiles according to an exemplary embodiment of the present invention.
FIG. 02.a shows an isometric view of an anode guide profile according to an exemplary embodiment of the present invention.
FIG. 02 shows an enlarged isometric view of the upper part of an anode guide profile according to an exemplary embodiment of the present invention.
FIG. 03 shows an isometric view of the Nucleus of the Modular System for Improving Electro-metallurgical Processes according to an exemplary embodiment of the present invention.
FIG. 04 shows an isometric view of a Horizontal Spacer according to an exemplary embodiment of the present invention.
FIG. 05 a-b show an isometric view of the Cathode type Nucleus Holder according to an exemplary embodiment of the present invention.
FIG. 06 shows an isometric view of the Anode Bracket type Nucleus Holder according to an exemplary embodiment of the present invention.
FIG. 07 shows an isometric view of the Head-type Nucleus Holder according to an exemplary embodiment of the present invention.
FIG. 08 shows an isometric view of the Nucleus positioned inside the cell, during the anode and cathode loading process according to an exemplary embodiment of the present invention.
FIG. 09 shows an isometric view of the Nucleus, with the cathode-type Nucleus holders, anode bracket type nucleus holders and head type nucleus holders installed in position according to an exemplary embodiment of the present invention.
The numbers that indicate the details in the different Figures, have the following meaning:

- 1. Cathode aligner
- 2. Cathode guide (in versions to insert a bare cathode or one with plastic stripping).
- 3. Shock absorber.
- 4. Anode aligner.
- 5. Anode guide.
- 6. Left longitudinal holding beam of the Upper Frame of the Nucleus.
- 7. Rear upper holder of the Upper Frame of the Nucleus.
- 8. Right rear corner pillar that joins the Upper and Lower Frames of the Nucleus.
- 9. Cathode guide.
- 10. Resting component of the Nucleus on the floor of the Electrolytic Cell.
- 11. Right longitudinal lower holding beam of the Nucleus lower Frame.
- 12. Right central pillar that joins the Nucleus Upper and Lower Frames.
- 13. Right diagonal of the Nucleus Frontal head.
- 14. Right front corner pillar that joins the Nucleus Upper and Lower Frames.
- 15. Right front transversal beam of the Nucleus Head of the lower Frame.
- 16. Left diagonal of the Nucleus Frontal head.
- 17. Intermediate front transversal reinforcement beam of the Nucleus Frontal Head.
- 18. Upper frontal transversal beam of the Nucleus Frontal Head.
- 19. Right longitudinal holding beam of the Nucleus Upper Frame.
- 20. Anode housing.
- 21. Cathode housing.
- 22. Diagonal lateral stiffener.
- 23. Window for crane coupling.
- 24. Coupling angle to the longitudinal Holding Beam of the Nucleus Upper Frame.
- 25. Bar of the Nucleus Holder, cathode type.
- 26. Anode-type Bracket of the Nucleus Holder.
- 27. Cube for bolting to the longitudinal support beam of the Nucleus Upper Frame.
- 28. Support to the upper head of the electrolytic cell masonry.
- 29. Tip that is fastened to the Nucleus.
- 30. Cathode
- 31. Anode

Description of the Modular System for Improving Electro-metallurgical Processes

An exemplary embodiment is of a modular system for improving electro-metallurgical processes is described in relation to FIGS. 1-8. It is structured as of a Fundamental Module, known as a Nucleus, represented in FIG. 03, to which other Modules or elements can be coupled or uncoupled to solve electro-metallurgical process problems such as those described previously in the Background section.
In the exemplary embodiment, the Nucleus of FIG. 03 is made up of an upper Frame formed by the left (6) and right (19) longitudinal holding beams and by the front or frontal (18) and rear (7) transversal supports, a lower Frame formed by the lower right longitudinal holding beams (11) and another equivalent one on the left side, and the lower beams of the Frontal heads (15) and their equivalent in the rear head. Both Frames are joined by means of right hand corner pillars (8) and (14) and their equivalent on the left side, one or more Intermediate Pillars such as that designated with the number (12) and one or more diagonals on the right side like the one designated with the number (22) and its equivalent on the left side. In both heads there are diagonals like those designated as (13) and (16) in the frontal head and other equivalent ones in the rear head. Optionally and depending on the dimensions of the Nucleus, reinforcement Beams can be incorporated like the one designated with number (17), both in the frontal and in the rear head. Optionally, in the lower longitudinal beams (11) and their opposite number on the left side, there are elements for resting on the floor of the cell, such as that designated with the number (10).
Depending on the problem that needs to be solved, independent modules with specific purposes can be attached to work in conjunction with the Nucleus, which is why it has been designed to be compatible with the following modules:

- Compatible with Module that eliminates borders or plastic strips.
- Compatible with Module for installation in a wet or dry cell.
- Compatible with hanging installation or installation resting on the bottom of the cell.
- Compatible with acid fog abatement module.
- Compatible with module for transversal circulation of electrolyte,
  Plastic Stripping Eliminator Module.

In this exemplary embodiment, the plastic stripping eliminator module is made up of a set of cathode guides (2) and optionally a set of anode guides (5) and/or a Spacer Module like the one shown in FIG. 04. Both the cathode guides (2) as well as the anode guides (5) can be installed, optionally, with their corresponding cathode aligners (1) and anode aligners (4), which are fixed in a vertical position on both interior sides of the Nucleus. The transversal profile of the cathode guide can be shaped like an omega, or a U and/or V, its length being greater than the length of the cathode immersed in the electrolyte, the width of the channel of the omega or of the U and/or of the V profile must be slightly greater than the thickness of the cathode in use. The cathode guides must be installed in such a way that the lower corners of the cathode, once the cathode is positioned in the cell, they are totally covered by the cathode guide. Optionally, the cathode guide can be reinforced with a shock absorber (3). The transversal profile of the anode guide (5) corresponds to a channel whose distance between opposing faces must be slightly greater than the thickness of the anode that will be employed. The aligners have the shape of a truncated cone or inverted truncated pyramid, open towards the center of the cell, and their function is to act as a funnel to facilitate the introduction of the cathodes and anodes respectively into the cell. Depending on the application, the cathode guides (1) may be used only with the anode guides (5), with or without aligners or the cathode guides only with a horizontal spacer module like the one in FIG. 04, or the cathode guides together with the anode guides and the horizontal spacer module.
Module for Installation in a Wet or in a Dry Cell.
The installation in a Wet or in a Dry Cell can be executed by attaching elements to the Nucleus that make it easier to lift and transfer it with the help of the traveling crane of the EW plant. These elements can be located in positions occupied by cathodes, by anodes or at the ends of the Nucleus. The version known as Cathode Type Nucleus Holder represented in FIG. 05 a-b, consists of a bar (25) with two windows for the Crane hooks (23) and two coupling angles to be attached to the longitudinal support beam of the Upper Frame of the Nucleus (24). Two or more of these cathode type Nucleus holders attached in positions normally occupied by cathodes are needed. The version known as Anode-type Bracket of the Nucleus Holder, represented in FIG. 06, consists of a Holder (26) joined to a Cube (27), to be attached by means of a bolt or other system, in two or more anode positions, in each one of the longitudinal support beams of the upper frame of the Nucleus. The version known as Head-type Nucleus Holder, represented in FIG. 07, consists of one end that rests on the electrolytic cell upper head masonry (28) and one end that is attached to the Nucleus (29). These holding systems can be used independently one at a time or in any combination thereof.
Likewise, they can remain installed permanently or be installed for their use and removed later. By using the plant's traveling crane, these holders make it possible to lift, introduce and/or remove the Nucleus from the cell with all the cathodes and anodes in position, whether the cell is empty or full of electrolyte.
Module for a Hanging Installation or One Resting on the Bottom of the Cell.
Depending on the type of operation that one wishes to carry out, it may or may not be convenient to rest the Nucleus on the bottom of the cell. When, for any reason, one wishes to avoid the resting on the bottom of the cell, the Head Assembly Support Module, consisting of four supports like the one shown in FIG. 07 may be installed. These supports are installed at the ends of the longitudinal support beams of the upper frame of the Nucleus (6) and (19), as shown in FIG. 09, and their projecting head support ends of the masonry electrolytic cell (28) are located directly over the heads of the cell itself, preventing the lower frame of the Nucleus from resting on the bottom of the cell.
Acid Fog Abatement Modules.
As mentioned previously, there are at least two systems patented in Chile to control the acid fog. The Modular System for Improving Electro-Metallurgical Processes of this Invention has been designed to make it compatible with the utilization of either of them.
Electrolyte Transversal Circulation Module.
A module is being developed to facilitate the transversal circulation of the electrolyte. The exemplary embodiments of the disclosed system is with such a module.

EXAMPLE OF APPLICATION

It order to experimentally verify the results of the application of the Modular System for Improving Electro-Metallurgical Processes, and without this meaning a limiting of the System's applicability, a pilot electrolytic cell built with fiberglass reinforced plastic, measuring 40 cm wide by 55 cm long and 35 cm deep was used to simulate an Industrial Electro-Winning Plant to obtain copper was made at a laboratory for which a pilot electrolytic cell was used, built of plastic reinforced with fiberglass, measuring 40 cm wide by 55 cm long and 35 cm deep.
The Nucleus of the Modular System for Improving Electro-Metallurgical Processes, similar to the one represented in FIG. 03, was introduced into this cell. The general dimensions of the Nucleus that was introduced into the Electrolytic Cell are 35 cm wide by 50 cm long and 35 cm high.
In the Nucleus used, a module of five cathode guides (2) was coupled to each side on the left (6) and right (19) longitudinal support beams and on the lower right longitudinal support beam (11) and its lower equivalent on the left side. All this with its corresponding cathode aligners (1). Next, a Horizontal Spacer, similar to the one shown in FIG. 04, was coupled at the bottom of the cell, with six pairs of anode housing (20) and five pairs of cathode housing (21). The distance between anodes as well as that between cathodes was fixed at 100 mm, the same one used in the simulated Industrial Plant.
Then the five stainless steel cathodes measuring 20 cm wide by 24 cm high by 2 mm thick, mounted on a copper cathodic bar having a diameter of 19 mm and a length of 40 cm, were introduced one by one; then six lead cathodes measuring 14.3 cm wide by 23.5 cm high by 2 mm thick, mounted on a copper anodic bar having the same dimensions as the cathodic bar, were introduced.
Once the cathodes and anodes had been loaded, the cell was filled with copper sulfate electrolyte, having a composition equivalent to that of the simulated Industrial Plant, and the deposit was started at a potential of 2.6 Volts between anode and cathode, employing a current density of 300 Amperes per square meter.
At the end of the operating cycle, the following was observed:
1. Both the chemical as well as the physical quality of the cathode improves. With regard to the chemical quality, a smaller content of Lead, Sulfur and Iron is reflected. On the other hand, the occlusion of copper sulfate on the borders of the deposit is eliminated because the Modular System for Improving Electro-Metallurgical Processes does not use plastic strip. With regard to the physical quality, by ensuring the parallelism between anodes and cathodes, the short-circuits are eliminated, the grain of the deposit is homogenized and refined, no copper ribbons were observed in any of edges of the copper cathode and a perfectly linear upper border of the cathodic deposit was obtained.
2. Current efficiency increases. How to take advantage of this benefit depends on the metal availability in the electrolyte. That is, the metal production can be increased, the electric power consumption can be reduced, or the harvesting cycle can be shortened.
3. Improves the increase of current density. This benefit is the direct result of confining the cathodes and anodes inside the Modular System for Improving Electro-Metallurgical Processes, that allows, according to the metal content in the electrolyte and without an additional investment, either increase the plant capacity, shorten the harvest cycle or reduce the number of cathodes per cell.
4. It provides an operational path for breaking the paradigm of distance between cathode and anode. This benefit is the direct result of the confinement of cathodes and anodes within the Modular System for Improving Electro-Metallurgical Processes that permits, according to the availability of copper and without an additional investment, either to increase the plant capacity by increasing the number of cathodes per cell, to shorten the harvest cycle, or reduce the number of cells.
5. Equitable distribution of the current through the cathodes. This benefit is translated into a lower variability of the current efficiency, of the weight of the cathodes, and of the chemical and physical quality of the cathodes.
6. Operational Improvements. The operational improvements include multiple benefits that arise from the absence of jacketed cathodes, absence of short-circuits and the ease with which the cathodes deposited can be loosened from the stainless cathode substrates with the Modular System for Improving Electro-Metallurgical Processes. The most important of these are: greater availability of equipment, reduction of human resources and reduction of raw materials costs. First, the factors that affect the greater availability of equipment are: 100% detaching in peeling machine, reduction of stripping frequency, increased useful life of the cathode, the anode and the cell, and increased availability of the traveling crane.
Second, the reduction of the Human Resources corresponds to the reduced supervision of short-circuits, manual detachment of plates and rectification of short-circuited cathodes.
Finally, the cost reduction associated to other supplies used in the EW process relates to the elimination of plastic borders, the elimination of cathode/anode spacers and the consumption reduction of chemical reagents.
Other modifications and variations to the invention will be apparent to those skilled in the art from the foregoing disclosure and teachings. Thus, while only certain embodiments of the invention have been specifically described herein, it will be apparent that numerous modifications may be made thereto without departing from the spirit and scope of the invention.

Claims

1. A modular system for improving electro-metallurgical processes comprising:

a nucleus formed by upper and lower rectangular frames, the nucleus;

at least one cathode guide being attached to at least one of longitudinal beams, the at least one cathode guide being operable to keep positive ions from reaching border or edge of the cathode; and

at least one anode guide.

2. The modular system of claim 1, wherein the nucleus is linked by at least one corner pillar.

3. The modular system of claim 1, wherein the nucleus is linked by at least one central pillar.

4. The modular system of claim 1, further comprising at least one diagonal reinforcement.

5. The modular system of claim 1, wherein the cathode guide has an omega type or u, or v cross-sectional shape.

6. The modular system of claim 1, wherein the cathode guide is operable to have a bare cathode inserted therein.

7. The modular system of claim 1, wherein the cathode guide is operable to have a cathode with plastic stripping on a periphery of the cathode inserted therein.

8. The modular system of claim 1, wherein the cathode guide has a cathode aligner attached thereto.

9. The modular system of claim 1, wherein the anode guide has an anode aligner attached thereto.

10. The modular system of claim 1, further comprising an anode space module.

11. The modular system of claim 1, further comprising at least two sets of cathode type support bars.

12. The modular system of claim 1, further comprising at least four sets of bracket anode supports.

13. The modular system of claim 1, further comprising at least a set of four head supports.

14. The modular system of claim 1 comprising at least two cathode guides facing each other and joined at their lower ends by means of a profile.

15. The modular system of claim 1 further comprising an acid fog abatement module.

16. The modular system of claim 1 further comprising further comprising an electrolyte transversal circulation module.

17. The modular system of claim 1 operable to be used in a treatment of liquid industrial waste.

18. The modular system of claim 1 operable to be used in electroplating.

19. A use of the system of claim 1 in a treatment of liquid waste or electroplating.