CA2240125A1 - Container for corrosive material - Google Patents
Container for corrosive material Download PDFInfo
- Publication number
- CA2240125A1 CA2240125A1 CA 2240125 CA2240125A CA2240125A1 CA 2240125 A1 CA2240125 A1 CA 2240125A1 CA 2240125 CA2240125 CA 2240125 CA 2240125 A CA2240125 A CA 2240125A CA 2240125 A1 CA2240125 A1 CA 2240125A1
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- Canada
- Prior art keywords
- vessels
- vessel
- solution
- enclosure
- adjacent
- Prior art date
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- Abandoned
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Abstract
An apparatus for recovering a metal from a toxic solution is disclosed. The apparatus includes a plurality of vessels (10, 10a, 10b) for containing the solution, each vessel (10) including an upper portion above the solution, electrode (50) extending into the solution in each vessel (10) for passing an electric current therethrough wherein toxic mist occurs in the upper portions of the vessels (10, 10a, 10b) above the surfaces of the solution, at least one pair of said vessels (10-10a and 10-10b) being disposed in a side-by-side relation to define spaces (44, 46) therebetween, and creating an airflow in the upper portion of the adjacent vessels from the space (44) between one pair of vessels (10-10a) to the space (46) between another pair of vessels (10-10b) for evacuating the toxic mist from above the solution in said vessels (10, 10a, 10b).
Description
CA 02240l2~ Igss-06-os CONTATN~R FOR CORROSIVE MATERIAL
BACKGROUND OF THE lN V~iN~l lON
This invention relates to a pollution control system and more particularly to a system for removing noxious mists from electrowinning cells.
Electrowinning of copper involves a process of recovering copper from a sulfuric acid solution by the passage of electric current between an anode which may be formed of a material such as lead and a copper cathode upon which the copper is harvested.
The process is normally carried out in an electrolytic cell in which a plurality of alternate anodes and cathodes are suspended from cell top furniture which extends along the sides of the vessel.
This process results in the formation of oxygen bubbles which rise to the surface of the electrolyte and bu~st thereby forming a mist of an acid such as sulfuric acid. This acid mist is hazardous to wor~ers and must be removed, or suppressed.
Attempts to solve the acid mist problem in copper electrowinning facilities include the use of large ventilation fans which can effectively reduce the mist, but involve high capital costs. Another solution is to cover the bath with foam strips located between the electrodes, or with layers of plastic beads or balls.
These solutions are also not satisfactory because the foam strips require the use of reagents which cont~m;n~nt the solvent extraction process. Plastic wos7/22736 PCT~S96/19707 balls have not been wholly satis~actory because they may affect cathode quality and beads are difficult to contain within the cells.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a new and improved method and apparatus for controlling acid mists in copper electrowinning cells.
This and other objects and advantages of the invention will become more detailed from the detailed description thereof taken with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE l is a side elevational view in section showing a cell according to the present invention;
FIGURE 2 is a view ta~en along lines 2-2 of Figure l;
FIGURE 3 is a partial plan view of the cell illustrated in Figure l; and FIGURE 4 is an enlarged fragmentary cross section showing a portion of the cell illustrated in Figure l.
DETATT.~ DESCRIPTION OF THE PREFERRED EMBODIMENT
Cell l0 according to the pre~erred embodiment of the invention is shown in the drawings to include a bottom 12, side walls 13 and 14, and end walls 15 and 16. The cell may be formed of any suitable material such as the polymer concrete disclosed in U.S. Patent No. 4,885,072 which is incorporated by reference ~ he.rein. The inner and outer surfaces of the cell may be coated with a corrosion-resistant lining as disclosed in U.S. Patent No. 5,079,050, which is incorporated by reference herein. A matrix of reinforcing bars (not shown), of a non-conductive material, such as FRP fiberglass, is disposed in the bottom 12 and extends at least up the side and end wal.ls 13, 14, 15 and 16 as reinforcement against damage.
An overflow box 18 is provided in a generally semi-circular ~ormation 19 integrally molded on the outer surface of the end wall 16 and adjacent the side wall 14. The overflow box 18 includes a recess 20 formed in the inner portion of formation 19 and opening into the interior of cell 10. An overflow pipe 21 is cast in the formation 19 and extends vertically from the recess 20 downwardly for connection to a sump for collection of the overflow electrolyte.
A longitudinal groove 24 formed on its inner surface 25 of side wall 14 and adjacent the upper end thereof. An adjustable weir 26 is fixed to the inner surface 25 of wall 14 and adjacent the ~ower portion of groove 24 in any suitable manner such as by means of screws 30 which extend through slots 31 formed in the weir 26 and which are receivable within threaded inserts 32 disposed in the wall 14 below groove 24.
The weir is formed of a suitable non-corrosive material and its upper edge includes a plurality of notches 34.
Fresh electrolyte is introduced into the cell by means of manifolds 36 ~Figure 2) which extend longitudinally along the bottom 12 and adjacent the side walls 13 and 14 and each has apertures 36 through which electrolyte flows into the cell 10. Overflow electrolyte flows through the notches 34 in weir 26, one end of which communicates with the overflow box 18. From the overflow box 18, the electrolyte flows downwardly through the overflow pipe 21.
The upper end of each of the side walls 13 and 14 has a plurality of spaced notches 40 and 42, respectively, which are distributed uniformly from end to end. The cells 10 in a copper electrowinning plant are arranged in a side-by-side and end-to-end relation as illustrated in Figure 2 where cell 10 is flanked by cells 10a and 10b in an alternating orientation such that the wall 13a of cell 10a is adjacent wall 13 of cell 10 and wall 14b of cell 10b is adjacent the wall 14 o~ cell 10. This defines a first space 44 between cells 10 and 10a and a second space 46 between cells 10 and lOb. The upper ends o~ the spaces 44 and 46 are closed by capping boards 48 which are supported on the upper edges of the side walls 13 and 13a and the CA 02240125 lsss-06-os W097/22736 PCT~S96/ls707 adjacent side walls 14 and 14b. As seen in Figure 2, the cell top furniture provides support for the electrodes 50 and extend from one end of the cells 10, lOa and 10~ to the other. The cell top furniture rests on the upper edges of the side walls 13, 13a, 14 and 14b so that a first series of gaps 52 are defined by the notches 40 and 40a in side walls 13 and 13a and a second series of gaps 54 and 54a are defined by the notches 42 and 42b in side walls 14 and 14b. This co~mtlnicates the interior o~ cells 10, lOa and lOb with the spaces 44 and 46.
The lower ends of the spaces 44 and 46 are closed by longitudinal flanges 52 and 54 extending respectively from the lower ends of the side walls 14 of cell 10 and flange 52a extending from the lower end of side wall 13a of cell lOa and flange 54b which extends from the lower end of side wall 14b of cell lOb. In a similar manner, the ends of space 44 are cla,sed by flanges 56 and 58 extending from each of the end. walls 15 and 16 of cell 10 and mating flanges 56a extending from the end walls of cell lOa and 58b ext.ending from the end walls of lOb.
An air delivery system 60 is connected by a conduit 62 to an opening 64 formed in the flanges 52 and: 52a for providing air under pressure to the space 44. An exhaust system 66 is connected by a conduit 68 to an opening 70 formed in the flanges 54 and 54b so tha.t the exhaust system 66 com~l~n;cates with the space CA 02240l2~ lsss-06-os W097/22736 pcT~ss6lls7o7 46.
In operation, air under pressure is delivered from the air system to the gap 44 and flows upwardly to the upper end thereof and out between the openings 52 and 5~a. As seen in Figure 3, the notches 40 are wider at their inner ends than the outer ends so that as the air flows through the gaps 52, it fans outwardly over the upper surface of the electrolyte. This forms an air curtain which entrains the acid mists and carries it across the upper end of the cell where it is drawn into the space 46, downwardly between the walls 14 and 14b and to the exhaust system 66. As a result, the acid mists can be captured and removed without the need for coverings such as foam pads, plastic balls or beads on the upper surface of the electrolyte. It will be appreciated that because both the inner and outer surfaces of the side walls 13 and 14 are exposed to the corrosive material, it is preferable that both the inner and outer surfaces of the cell 10 be coated with a corrosion resistant material.
BACKGROUND OF THE lN V~iN~l lON
This invention relates to a pollution control system and more particularly to a system for removing noxious mists from electrowinning cells.
Electrowinning of copper involves a process of recovering copper from a sulfuric acid solution by the passage of electric current between an anode which may be formed of a material such as lead and a copper cathode upon which the copper is harvested.
The process is normally carried out in an electrolytic cell in which a plurality of alternate anodes and cathodes are suspended from cell top furniture which extends along the sides of the vessel.
This process results in the formation of oxygen bubbles which rise to the surface of the electrolyte and bu~st thereby forming a mist of an acid such as sulfuric acid. This acid mist is hazardous to wor~ers and must be removed, or suppressed.
Attempts to solve the acid mist problem in copper electrowinning facilities include the use of large ventilation fans which can effectively reduce the mist, but involve high capital costs. Another solution is to cover the bath with foam strips located between the electrodes, or with layers of plastic beads or balls.
These solutions are also not satisfactory because the foam strips require the use of reagents which cont~m;n~nt the solvent extraction process. Plastic wos7/22736 PCT~S96/19707 balls have not been wholly satis~actory because they may affect cathode quality and beads are difficult to contain within the cells.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a new and improved method and apparatus for controlling acid mists in copper electrowinning cells.
This and other objects and advantages of the invention will become more detailed from the detailed description thereof taken with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGURE l is a side elevational view in section showing a cell according to the present invention;
FIGURE 2 is a view ta~en along lines 2-2 of Figure l;
FIGURE 3 is a partial plan view of the cell illustrated in Figure l; and FIGURE 4 is an enlarged fragmentary cross section showing a portion of the cell illustrated in Figure l.
DETATT.~ DESCRIPTION OF THE PREFERRED EMBODIMENT
Cell l0 according to the pre~erred embodiment of the invention is shown in the drawings to include a bottom 12, side walls 13 and 14, and end walls 15 and 16. The cell may be formed of any suitable material such as the polymer concrete disclosed in U.S. Patent No. 4,885,072 which is incorporated by reference ~ he.rein. The inner and outer surfaces of the cell may be coated with a corrosion-resistant lining as disclosed in U.S. Patent No. 5,079,050, which is incorporated by reference herein. A matrix of reinforcing bars (not shown), of a non-conductive material, such as FRP fiberglass, is disposed in the bottom 12 and extends at least up the side and end wal.ls 13, 14, 15 and 16 as reinforcement against damage.
An overflow box 18 is provided in a generally semi-circular ~ormation 19 integrally molded on the outer surface of the end wall 16 and adjacent the side wall 14. The overflow box 18 includes a recess 20 formed in the inner portion of formation 19 and opening into the interior of cell 10. An overflow pipe 21 is cast in the formation 19 and extends vertically from the recess 20 downwardly for connection to a sump for collection of the overflow electrolyte.
A longitudinal groove 24 formed on its inner surface 25 of side wall 14 and adjacent the upper end thereof. An adjustable weir 26 is fixed to the inner surface 25 of wall 14 and adjacent the ~ower portion of groove 24 in any suitable manner such as by means of screws 30 which extend through slots 31 formed in the weir 26 and which are receivable within threaded inserts 32 disposed in the wall 14 below groove 24.
The weir is formed of a suitable non-corrosive material and its upper edge includes a plurality of notches 34.
Fresh electrolyte is introduced into the cell by means of manifolds 36 ~Figure 2) which extend longitudinally along the bottom 12 and adjacent the side walls 13 and 14 and each has apertures 36 through which electrolyte flows into the cell 10. Overflow electrolyte flows through the notches 34 in weir 26, one end of which communicates with the overflow box 18. From the overflow box 18, the electrolyte flows downwardly through the overflow pipe 21.
The upper end of each of the side walls 13 and 14 has a plurality of spaced notches 40 and 42, respectively, which are distributed uniformly from end to end. The cells 10 in a copper electrowinning plant are arranged in a side-by-side and end-to-end relation as illustrated in Figure 2 where cell 10 is flanked by cells 10a and 10b in an alternating orientation such that the wall 13a of cell 10a is adjacent wall 13 of cell 10 and wall 14b of cell 10b is adjacent the wall 14 o~ cell 10. This defines a first space 44 between cells 10 and 10a and a second space 46 between cells 10 and lOb. The upper ends o~ the spaces 44 and 46 are closed by capping boards 48 which are supported on the upper edges of the side walls 13 and 13a and the CA 02240125 lsss-06-os W097/22736 PCT~S96/ls707 adjacent side walls 14 and 14b. As seen in Figure 2, the cell top furniture provides support for the electrodes 50 and extend from one end of the cells 10, lOa and 10~ to the other. The cell top furniture rests on the upper edges of the side walls 13, 13a, 14 and 14b so that a first series of gaps 52 are defined by the notches 40 and 40a in side walls 13 and 13a and a second series of gaps 54 and 54a are defined by the notches 42 and 42b in side walls 14 and 14b. This co~mtlnicates the interior o~ cells 10, lOa and lOb with the spaces 44 and 46.
The lower ends of the spaces 44 and 46 are closed by longitudinal flanges 52 and 54 extending respectively from the lower ends of the side walls 14 of cell 10 and flange 52a extending from the lower end of side wall 13a of cell lOa and flange 54b which extends from the lower end of side wall 14b of cell lOb. In a similar manner, the ends of space 44 are cla,sed by flanges 56 and 58 extending from each of the end. walls 15 and 16 of cell 10 and mating flanges 56a extending from the end walls of cell lOa and 58b ext.ending from the end walls of lOb.
An air delivery system 60 is connected by a conduit 62 to an opening 64 formed in the flanges 52 and: 52a for providing air under pressure to the space 44. An exhaust system 66 is connected by a conduit 68 to an opening 70 formed in the flanges 54 and 54b so tha.t the exhaust system 66 com~l~n;cates with the space CA 02240l2~ lsss-06-os W097/22736 pcT~ss6lls7o7 46.
In operation, air under pressure is delivered from the air system to the gap 44 and flows upwardly to the upper end thereof and out between the openings 52 and 5~a. As seen in Figure 3, the notches 40 are wider at their inner ends than the outer ends so that as the air flows through the gaps 52, it fans outwardly over the upper surface of the electrolyte. This forms an air curtain which entrains the acid mists and carries it across the upper end of the cell where it is drawn into the space 46, downwardly between the walls 14 and 14b and to the exhaust system 66. As a result, the acid mists can be captured and removed without the need for coverings such as foam pads, plastic balls or beads on the upper surface of the electrolyte. It will be appreciated that because both the inner and outer surfaces of the side walls 13 and 14 are exposed to the corrosive material, it is preferable that both the inner and outer surfaces of the cell 10 be coated with a corrosion resistant material.
Claims (12)
1. An apparatus for recovering a metal from a toxic solution and including a plurality of vessels for containing the solution, each vessel including an upper portion above the solution, electrode means extending into the solution in each vessel for passing an electric current therethrough wherein toxic mist occurs in the upper portions of the vessels above the surfaces of the solution, at least one pair of adjacent vessels being disposed in a side-by-side relation, the outer surfaces of side walls of the adjacent vessels defining a space therebetween, means for closing the margins of the space to define an enclosure, and means for creating an airflow in the upper portions of the adjacent vessels and over the surfaces of the solution in said adjacent vessels and outwardly from said vessels and into the enclosure defined by the outer surface of the vessel side walls for evacuating the toxic mist from above the solution in said vessels.
2. The apparatus set forth in claim 1 wherein the side walls of the adjacent vessels have upper and lower ends for defining upper and lower portions of said enclosure, suction producing means coupled to the lower end of the enclosure for drawing the toxic mist downwardly between the side walls of the vessels.
3. The apparatus set forth in claim 2 wherein the means for enclosing said space includes a first member extending across the gap between the upper ends of the adjacent side walls and a second member extending between lower ends of said side walls.
4. The apparatus set forth in claim 3 wherein said vessels have and electrode support extending along the upper end of the side walls, and openings formed beneath the electrode support for communicating the vessels with the enclosure.
5. An apparatus for recovering a metal from a toxic solution and including a plurality of vessels for containing the solution, each vessel including an upper portion above the solution, electrode means extending into the solution in each vessel for passing an electric current therebetween wherein a toxic mist occurs in the upper portions of the vessels and above the surfaces of the solution, said vessels being disposed in a side-by-side relation and each including first and second side walls, each sidewall having an outer surface disposed in an opposed relation to the outer surface of an adjacent vessel to define a first space between a first vessel and a second vessel adjacent one side of the first vessel and a second space between the first vessel and a third vessel adjacent the other side of the first vessel, means for enclosing said first and second spaces to define first and second enclosures, means for communicating the upper portions of the first and second vessels with the first enclosure and the upper portions of the first and third vessels with said second enclosure, means for creating a positive pressure in the first enclosure and means for creating a suction in the second enclosure whereby currents are created in the upper portions of the vessels causing the toxic mist to flow out of said first and third vessels and into said second enclosure.
6. The apparatus set forth in claim 5 wherein said suction producing means is coupled to the lower end of the second enclosure for drawing the toxic mist downwardly between the outer side surfaces of the first and third vessels.
7. The apparatus set forth in claim 6 wherein the means for creating pressure in the first enclosure is coupled to the lower end thereof for introducing air under pressure into the lower end of the first enclosure, said air flowing over the upper portion of the vessels for entraining the toxic mist and carrying said mist into the second enclosure.
8. The apparatus set forth in any of claims 6 or wherein each of said vessels have an upper end, the means for enclosing said spaces includes a first member extending across the gap between the upper ends of the side walls of the vessels and a second member extending between adjacent the lower ends of the side walls of said vessels.
9. The apparatus set forth in any of claims 6-8 wherein the vessels have means extending along the upper end of the side walls for supporting said electrodes, and openings formed beneath the electrode supporting means for communicating the vessels with the first and second enclosures.
10. A method of electrowinning copper comprising the steps of disposing a solution containing copper ions and sulfuric acid in a vessel, suspending a plurality of electrodes in the solution, passing an electric current between said electrodes, wherein copper is harvested on one of the electrodes and wherein a mist of sulfuric acid is generated and collects above the surface of the solution, passing an air current from one side of the vessel to the other and across the surface of the solution for entraining the sulfuric acid mist, collecting the entrained sulfuric acid mist and air in an enclosure formed on two sides by the outer surfaces of two adjacent vessels and drawing the air and entrained acid mist downwardly in an enclosure defined on two sides by the outer surfaces of the adjacent vessels and collecting said acid mist adjacent the lower end of the enclosure.
11. An apparatus for recovering a metal from a toxic solution and including a pair of vessels for containing the solution, each of said vessels including an upper portion above the solution, electrode means extending into the solution for passing an electric current therebetween wherein toxic mist occurs in the upper portions of the vessels above the surface of the solution, each of said vessels including side walls having an outer surface, said vessels being disposed in a side by side relation with one side wall of a first vessel being located adjacent one side wall of the second vessel to define a space, means for closing said space to define an enclosure, means for creating an air flow in the upper portion of the vessel and over the surface of the solution and outwardly from said vessel and into said enclosure for evacuating the toxic mist from above the solution in said vessel and means for creating a suction coupled to the lower end of the space for drawing the toxic mist downwardly along the side of the vessel.
12. The apparatus set forth in claim 11 and including a third vessel provided with a side wall having an outer surface the third vessel being disposed adjacent the first vessel with the outer surface of the third vessel adjacent to the outer side wall surface of the first vessel to define a second space which communicates with the upper end of the vessel, means enclosing the second space to define a second enclosure, means coupled to said second enclosure for creating pressure therein for producing an air flow across the upper end of said first vessel and into said first enclosure for entraining the toxic mist and carry said mist into the first enclosure.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US881595P | 1995-12-18 | 1995-12-18 | |
| US60/008,815 | 1995-12-18 | ||
| PCT/US1996/019707 WO1997022736A1 (en) | 1995-12-18 | 1996-12-11 | Container for corrosive material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2240125A1 true CA2240125A1 (en) | 1997-06-26 |
Family
ID=29405597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2240125 Abandoned CA2240125A1 (en) | 1995-12-18 | 1996-12-11 | Container for corrosive material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2240125A1 (en) |
-
1996
- 1996-12-11 CA CA 2240125 patent/CA2240125A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |