KR20160092065A - Electrochemical cell used in production of hydrogen using cu-cl thermochemical cycle - Google Patents

Abstract

The electrochemical cell consists of a hollow tube and a copper rod in the center. The tube has first and second ends. A first end cap is used to close the first open end. An anode liquid inlet extends through the first end cap in the anode liquid compartment and a cathode liquid inlet extends through the first end cap in the catholyte compartment. The anode liquid and cathode liquid compartments are separated by an ion exchange membrane fixed on an inner hollow tube having pores on the surface. A first Teflon gasket is provided for the inlet of the anode liquid and a catholyte tube is secured between the first tube end and the first end cap. The copper rod lies at the center of the tube and acts as a cathode. An annular ring is provided which acts as a scraper for removing deposited copper. A second end cap is used to close the second opening. A second Teflon gasket is secured between the second tube end and the second end cap. The second end cap is provided for the anode liquid outlet and includes a conical dome for collecting the deposited copper and for transporting it along with the cathodic liquid. An anode actor and a cathode liquid trough are connected to the anode liquid and cathode liquid half cell through the tubes. The anode liquid and cathode liquid are recycled through a peristaltic pump, one on each side.

Description

ELECTROCHEMICAL CELL USED IN PRODUCTION OF HYDROGEN USING CU-CL THERMOCHEMICAL CYCLE FIELD OF THE INVENTION [0001]

The present invention relates to a copper powder of cuprous chloride and a tubular electrochemical cell for electrolysis into cupric chloride. The material used to fabricate the cell is dense copper rod as a dense graphite tube and cathode as the anode, separated by an ion exchange membrane supported by an acrylic tube. The electrochemical cell of the present invention can be used to recover the metals from a salt solution of a metal such as silver, zinc and lead.

Many industries, such as plating, mining and metal surface treatment, have also used electrolysis to recover metals from electrolytes. It is a well known process to recover copper from a solution containing copper metal in the form of ions. Copper consumption in the hydrogen production stage in the CuCl cycle is regenerated on the cathode side of the electrolysis. The cupric chloride formed at the anode side was used as the starting material for the hydrolysis of cupric chloride and for the decomposition of cupric chloride.

US005421966A used an electrolytic process for the regeneration of a cupric acid etchant for the recovery of copper metal. Applicants have used graphite rods as anode and cathode electrodes. The microporous separator was used for separating the anolyte and the catholyte.

US20080283390A1 discloses a method for electrolysis of cuprous chloride for the production of copper powder and cupric chloride. Dense graphite was used as the working electrode, such as an anode and a cathode. Anion exchange membranes constructed from crosslinked poly and polyethylene imines are used as separation media. The electrodes are designed in the form of a channel lip. Electrolyte flows through each channel. The main problem encountered is the removal of the copper powder formed during the electrolysis. Applicants have used various additives to increase the solubility of CuCl. The carbon black material was seeded to increase the conductivity of the solution.

US2010051469A1 used an electrochemical cell to produce hydrogen gas and cupric chloride from electrolysis of cuprous chloride. The anolyte solution and the catholyte solution used were hydrochloric acid and cuprous chloride in water, respectively. A cation exchange membrane was used as a separation medium between the anode and the cathode compartment.

Object of the invention

One of the objectives of the present invention is to design an electrochemical cell for the electrolysis of cuprous chloride using an acid-resistant material to obtain a copper powder of the required size.

A further object of the present invention is to recover these metals from a salt solution of a metal such as silver, zinc and lead.

It is a further object of the present invention to obtain the desired particles of the metal to be recovered.

It is another object of the present invention to design an electrochemical cell having an anode and a cathode of a surface area effective for a desired metal particle.

SUMMARY OF THE INVENTION

Thermochemical Cu-Cl thermochemical cycles consist of six steps: (1) hydrogen production; (2) electrolysis of cuprous chloride; (3) drying of cupric chloride; (4) hydrolysis of cupric chloride; (5) decomposition of cupric chloride; And (6) an oxygen production step. The tubular / cylindrical electrochemical cell of the present invention is used to produce copper.

The metal recovery electrochemical cell of the present invention comprises

Dense graphite as an anode,

Dense copper as a cathode, and

An ion exchange membrane supported by a corrosion resistant material

.

The electrochemical cell of the present invention can recover these metals from salt solutions of metals such as copper, silver, zinc and lead at high or very low concentrations.

According to one aspect of the present invention, there is provided an electrochemical cell for producing copper from cuprous chloride generated in a copper-chlorine (Cu-Cl) thermochemical cycle.

The high surface area ratio of the anode to cathode provides a maximum cathode current density to provide a fine and uniform particle size.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described with reference to the accompanying drawings,
Figure 1 illustrates an embodiment of an electrochemical cell according to one embodiment of the present invention.
Figure 2 is a schematic representation of a corrosion resistant material such as acrylic as a support for graphite anodes, copper cathodes, and membranes used in the present invention.
3 is a schematic view of a first end and a second end used in an electrochemical cell;
4 is a schematic view of a first end and a second end teflon gasket and a mechanical scraper used in an electrochemical cell.
Figure 5 shows a scanning electron microscope (SEM) image of deposited copper powder.
Figure 6 shows an X-ray diffraction (XRD) pattern of the deposited copper powder.
Figure 7 shows a scanning electron microscope (SEM) image of the deposited silver powder.
Figure 8 shows an X-ray diffraction (XRD) pattern of the deposited silver powder.
Figure 9 shows a scanning electron microscope (SEM) image of the deposited zinc powder.
Figure 10 shows an X-ray diffraction (XRD) pattern of the deposited zinc powder.
Figure 11 shows a scanning electron microscope (SEM) image of the deposited lead powder.
Figure 12 shows an X-ray diffraction (XRD) pattern of the deposited lead powder.

The present invention relates to the electrolysis of cuprous chloride to the copper powder on the cathode side of the cell and the formation of cupric chloride on the anode side. By carrying out the present invention, it is possible to electrolyze the cuprous chloride and effectively remove and recover the copper powder formed during the electrolysis. The electrolytic cell is manufactured using a tubular graphite anode and a copper rod separated by an ion exchange membrane supported by an acrylic cylinder.

The tubular electrochemical cell of the present invention is used to produce copper. Similarly, the same tubular / cylindrical electrochemical cell can be used for other metals such as silver, zinc and lead.

By practicing the present invention, the metal can be effectively recovered by the electrochemical cell of the present invention, wherein the electrolysis of the electrolyte for recovering the metal is performed. The electrolytic cell is constructed using a copper rod and a graphite cylinder separated by an ion exchange membrane supported by an acid-resistant substance.

Such as removal of copper powder deposited on the cathode, acquisition of the copper powder of the desired size in a subsequent process, removal of the copper powder from the closed loop, and scale-up of the electrolyte cell, The main problems in the electrolysis of cuprous chloride are solved by practicing the present invention.

The metal recovery electrochemical cell of the present invention comprises at least one anode disposed in an electrolyte; One or more cathodes disposed in the electrolyte; At least one ion exchange membrane disposed between the anode compartment and the cathode compartment; A corrosion resistant material support for an ion exchange membrane; One or more scrapers to remove deposited metal from the cathode, and one or more cathode liquid trap to collect the discarded metal powder.

The present invention deals with a closed loop electrochemical cell (1) for use in electrolysis of cuprous chloride as shown in Fig.

According to the present invention, the anode 2 is composed of a graphite cylinder with a dense open end as shown in Fig. The electrode is impermeable to gases and liquids. A dense copper rod is used as the cathode. A copper rod 3 (shown in Fig. 2) having a smooth working surface lies in the center of the graphite cylinder, axially parallel to the length of the cylinder. Only the required surface is exposed to the catholyte and the remaining surface is coated with an electrically resistive material. An acrylic groove 21 is provided at the base of the copper rod to provide mechanical support.

According to the invention, the distance between the anode and the cathode can be varied by changing the inner diameter of the graphite tube / cylinder and the outer diameter of the copper rod. The separation of the anolyte and the catholyte is carried out using an anion exchange membrane 4 having a support of an acrylic cylinder 5 (shown in Fig. 2) placed between the anode and the cathode.

In the present invention, holes are formed on the surface of an acrylic cylinder acting as a support for the anion exchange membrane for the passage of ions between the anode liquid and the cathode liquid. The diameter of the acrylic cylinder used for electrolysis is slightly less than half the inner diameter of the graphite tube / cylinder used as the anode. The cathode therefore coaxially lies at the center of the anode.

In the present invention, the graphite cylinder and the acrylic cylinder have a similar length. The first open ends of the graphite cylinder and the acrylic cylinder are packed with the aid of a first end cap 6 and the second open ends of the graphite cylinder and the acrylic cylinder are packed into a second end cap 7. The second end cap shown in Fig. 3 has a conical dome 13 at the center. The end caps are all made of an acrylic material. A first Teflon gasket (8) is secured between the first open end and the first end cap. The above is provided for the inlet of the anode liquid tube 9, the cathode liquid tube 10, the copper rod 3 and the mechanical scraper 19. A second Teflon gasket (11) is placed between the second end and the second end cap, which is provided for the anode liquid outlet (12) and the catholyte passage (13). The cone has an upper diameter equal to the inner diameter of the acrylic tube and a solid angle of 40 [deg.]. Which collects the copper particles separated from the cathode surface and transports them to the cassette fluid trapper 14 where the collected copper is discharged from the end of the discharge port 15 via a stopper (not shown) connected to the cassette fluid trapper Removed.

A top view of the first Teflon gasket and the second Teflon gasket is shown in Fig. The first Teflon gasket is provided for the inlet of the anode liquid. The catholyte tube lies between the first tube end and the first end cap. The outlet 12 of the anode compartment and the outlet 7 of the cathode compartment are connected to the inlet of the anode actor 16 and the cathode coupler 14, respectively. At the base of the cassette coupler, the copper settled by gravity is removed. The outlet 17 of the anode actor is used to remove cupric chloride and other salt solutions for other metals formed from the copper recovery. The anode liquid closed loop is completed by circulating the anode liquid from the anode actuator wrapper to the inlet provided to the anode liquid side of the electrochemical cell using the peristaltic pump P1. Similarly, the catholyte closed loop is accomplished by circulating the catholyte from the cassette fluid trap to the inlet provided to the catholyte of the electrochemical cell using peristaltic pump P2.

The power supply is provided by a rectifier (18). A required amount of current is passed through the electrolyte. The anode end of the rectifier is connected to a graphite tube / sylinder, which serves as the anode, and the anode end is connected to a copper rod acting as a cathode.

The first end and the second end of the cell are maintained completely using the nut bolts 20 as shown in Fig.

Thus, one embodiment of the present invention is that the anode can be composed of a corrosion-resistant conductive metal, a conductive carbon material, and any non-conductive material coated by the conductive material. Furthermore, the anode may be graphite and the anode may be hollow.

One embodiment of the present invention is that the cathode can be composed of a corrosion-resistant conductive metal, a conductive carbon material, and any non-conductive material coated with a conductive material. Thus, the cathode can be copper and can have any geometric shape by keeping both ends of the anode open.

The anode and cathode range from 1: 1 to 1:50; Most preferably from 1: 6 to 1: 15.

It has been found that the support is made of a corrosion-resistant and non-conductive material and can be selected from ceramic, thermoplastic and thermoset polymeric materials.

Another embodiment of the present invention is that openings for ion transport from an anode liquid to a catholyte are provided on a support in an electrochemical cell wherein these openings on the support can have any geometric shape. However, in the case of the present invention, these openings on the support have a uniformly distributed area with an arbitrary size and an area ranging from 10% to 95% of the total area of the support.

One embodiment of the present invention is that a scraper is provided in the cathode and is comprised of a corrosion-resistant and non-conductive material. The scrapers may be composed of ceramic, thermoplastic or thermosetting polymeric materials.

An electrochemical cell according to the invention wherein the anode and cathode are partially coated with a corrosion-resistant and non-conductive material.

One embodiment of the present invention is that the cathode is partially coated with a corrosion-resistant and non-conductive material.

One of the embodiments of the present invention is that the anode is partially coated with a corrosion-resistant and non-conductive material.

One of the embodiments of the present invention is that the cathode may be partially coated with a nonconductive material and / or the cathode may be partially coated with a nonconductive material on at least one side.

In the present invention, during operation, the electrolyte proceeds to a closed loop system. By passage current at specific time intervals, copper is deposited on the cathode surface in the form of powder. The current is stopped for a while and the deposited copper is removed using a mechanical scrubber 19 (Fig. 4). This effect causes copper to be removed from the cathode surface. After removing the copper powder, turn on the current again. The size and shape of the deposited powder varies with operating conditions. The above procedure was performed alternately.

While the present invention has been described with reference to exemplary embodiments, those skilled in the art will recognize that the invention can be practiced with modification and within the spirit and scope of the appended claims.

Example

Example  One

According to the present invention, recovery of copper metal by electrolysis of cuprous chloride was carried out in the above-mentioned electrochemical cell using cuprous chloride in hydrochloric acid as an electrolyte. The electrolyte was pumped through each compartment using a peristaltic pump.

Recovery of copper metal from cuprous chloride was carried out at room temperature applying a current density of 100 mA / cm 2 cathode. Scanning electron microscopy (SEM) images obtained for copper metal formed during electrolysis are shown in FIG. An X-ray diffraction (XRD) pattern of deposited copper is shown in FIG.

Example  2

According to the present invention, silver metal recovery by electrolysis of silver nitrate was carried out in the above-mentioned electrochemical cell using silver nitrate in nitric acid as an electrolyte. The electrolyte was pumped through each compartment using a peristaltic pump.

Recovery of the silver metal from silver nitrate was carried out at room temperature using a 60 mA / cm 2 cathode current density. Scanning electron microscopy (SEM) images obtained for silver metal formed during electrolysis are shown in FIG. The X-ray diffraction (XRD) pattern of the deposited silver is shown in Fig.

Example  3

According to the present invention, recovery of zinc metal by electrolysis of zinc nitrate was carried out in the above-mentioned electrochemical cell using zinc nitrate in nitric acid as an electrolyte. The electrolyte was pumped through each compartment using a peristaltic pump.

Recovery of the zinc metal from zinc nitrate was carried out at room temperature with a current density of 100 mA / cm 2 applied. Scanning electron microscopy (SEM) images obtained for the zinc metal formed during electrolysis are shown in FIG. The X-ray diffraction (XRD) pattern of deposited zinc is shown in FIG.

Example  4

According to the present invention, recovery of lead metal by electrolysis of lead nitrate was carried out in the above-mentioned electrochemical cell using zinc nitrate in nitric acid as an electrolyte. The electrolyte was pumped through each compartment using a peristaltic pump.

Recovery of lead metal from zinc nitrate was carried out at room temperature with a current density of 100 mA / cm 2 cathode applied. Scanning electron microscopy (SEM) images obtained for lead metals formed during electrolysis are shown in FIG. An X-ray diffraction (XRD) pattern of deposited zinc is shown in FIG.

Claims (21)

a) at least one anode disposed in the electrolyte;
b) one or more cathodes disposed in the electrolyte;
c) at least one anion exchange membrane disposed between the anode compartment and the cathode compartment;
d) a corrosion resistant material as a support for anion exchange membranes;
e) at least one scraper for removing deposited metal from the cathode;
f) one or more cathode liquid traps for collecting the discarded metal powder;
A metal recovery electrochemical cell comprising:
The cathode and the anode have a surface area ratio in the range of 1: 6 to 1: 50,
Said support having an opening, said opening occupying a surface area ranging from 10% to 95% of the total area of said support,
Wherein the cathode is rod-shaped and coaxial with the anode and is at the center of the anode. The method according to claim 1,
An electrochemical cell in which the anode is comprised of a corrosion-resistant conductive metal, a conductive carbon material, or a non-conductive material coated with a conductive material. The method according to claim 1,
An electrochemical cell in which the anode is graphite. The method according to claim 1,
An electrochemical cell in which the anode is hollow. The method according to claim 1,
An electrochemical cell in which the cathode is composed of a non-conductive material coated with a corrosion-resistant conductive metal, a conductive carbon material, or a conductive material. The method according to claim 1,
An electrochemical cell in which the cathode is copper. The method according to claim 1,
An electrochemical cell in which both ends of the anode are kept open. The method according to claim 1,
Wherein the cathode and the anode have a surface area ratio in the range of 1: 6 to 1:15. The method according to claim 1,
An electrochemical cell wherein the support is made of a corrosion-resistant and non-conductive material. The method according to claim 1,
An electrochemical cell wherein the support is comprised of a ceramic, thermoplastic or thermoset polymeric material. The method according to claim 1,
An electrochemical cell in which openings are uniformly distributed on a support. The method according to claim 1,
An electrochemical cell provided with a scraper composed of a corrosion-resistant and non-conductive material. The method according to claim 1,
An electrochemical cell wherein the scraper is comprised of a ceramic, thermoplastic or thermoset polymeric material. The method according to claim 1,
And the deposited particle size of the obtained copper powder has a particle size in the range of 0.001 to 1000 mu m. The method according to claim 1,
Wherein the discarded metal powder is one of copper, silver, zinc, and lead. 17. The method of claim 16,
An electrochemical cell wherein the discarded metal powder is copper. The method according to claim 1,
An electrochemical cell in which the anode and cathode are partially coated with a corrosion-resistant and non-conductive material. The method according to claim 1,
An electrochemical cell in which the cathode is partially coated with a corrosion-resistant and non-conductive material. The method according to claim 1,
An electrochemical cell in which the anode is partially coated with a corrosion-resistant and non-conductive material. The method according to claim 1,
An electrochemical cell in which the cathode is partially coated with a non-conductive material. The method according to claim 1,
An electrochemical cell in which the cathode is at least partially coated with a non-conductive material.

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