Electrochemical cell and process for producing metal and a co-product from metal oxide and an aqueous halide salt

Patent metadata

Field	Value
Publication number	US-2024200217-A1
Application number	US-202418582228-A
Country	US
Kind code	A1
Filing date	Feb 20, 2024
Priority date	Jun 7, 2022
Publication date	Jun 20, 2024
Grant date	—

Abstract

An electrochemical cell and process for producing metal and a co-product from metal ore and an aqueous halide salt are described. The co-product may be a metal hydroxide, halogen, oxygen, and/or a hypohalite. The cell includes a cathode, an anode, and a separator. A catholyte includes (i) water, (ii) a metal hydroxide comprising Q, where Q is an alkali metal, an alkaline earth metal, or a combination thereof, and (iii) suspended metal ore particles comprising MxOy where M is a metal and x and y are integers. An anolyte includes (i) water and (ii) a halide salt comprising Q and X where X is Cl or Br. A process for producing metal includes applying a voltage across the electrochemical cell to effect reduction of the MxOy in the cathode compartment to provide the metal M and a hydroxide comprising Q. X2, O2, and/or XO− is formed in the anode compartment.

First claim

We claim:

1 . An electrowinning process , comprising:
providing an electrochemical cell comprising (i) a cathode comprising low-carbon steel, copper, iron, graphite, vitreous carbon, or titanium, (ii) an anode comprising an oxide coating comprising Ru, Pt, Ir, or any combination thereof, on a conducting substrate, (iii) a separator between the cathode and the anode, the separator comprising a porous composite or a cation-selective membrane, and (iv) a voltage source electrically connected to the cathode and the anode; providing a catholyte comprising (i) water, (ii) a metal hydroxide comprising Q, where Q is an alkali metal, an alkaline earth metal, or a combination thereof, and (iii) suspended metal ore particles comprising M x O y where M is a metal and x and y are integers; providing an anolyte comprising water and a halide salt comprising Q and X, where X is Cl, Br, or a combination thereof; and applying a voltage across the electrochemical cell to effect (i) reduction of the M x O y in the catholyte to provide the metal M and additional metal hydroxide comprising Q, and (ii) production of O 2 , X 2 , XO − , or any combination thereof in the anolyte.

2 . The electrowinning process of claim 1 , wherein:
the anolyte has a bulk average pH≤3 and X 2 production is greater than O 2 production; or the anolyte has a bulk average 3<pH<7 and XO − production is greater than O 2 and/or X 2 production; or the anolyte has a bulk average pH≥7 and O 2 production is greater than X 2 production.

3 . The electrowinning process of claim 2 , wherein:
the anolyte has a pH≤3 and the anode is in direct contact with the separator; or the anolyte has a pH≥7 and the anode is spaced apart from the separator.

4 . The electrowinning process of claim 1 , applying the voltage across the electrochemical cell further effects production of H 2 in the catholyte.

5 . The electrowinning process of claim 1 , wherein:
(i) M is Fe, Mn, Ni, Cr, Co, Zn, or any combination thereof; or (ii) Q is Li, Na, K, Rb, Cs, Mg, Ca, or any combination thereof; or (iii) both (i) and (ii).

6 . The electrowinning process of claim 1 , wherein:
(i) the metal ore particles comprise Fe 2 O 3 ; or (ii) Q is Na; (iii) X is Cl; or (iv) any combination of two or more of (i), (ii), and (iii).

7 . The electrowinning process of claim 1 , wherein:
(i) the catholyte comprises from 50 g/L to 500 g/L of the suspended metal ore particles prior to applying the voltage; or (ii) the catholyte comprises from 10 wt % to 50 wt % of the metal hydroxide prior to applying the voltage; or (iii) the anolyte comprises from 10 wt % to 50 wt % of the halide salt prior to applying the voltage; or (iv) any combination of two or more of (i), (ii), and (iii).

8 . The electrowinning process of claim 1 , further comprising:
(i) continuously or periodically removing X 2 and/or O 2 generated in the anolyte; or (ii) periodically removing at least a portion of the metal M from the cathode; or (iii) continuously or periodically removing H 2 generated in the catholyte; or (iv) any combination of two or more of (i), (ii), and (iii).

9 . The electrowinning process of claim 1 , further comprising:
(i) periodically adding a quantity of the metal ore particles to the catholyte; or (ii) periodically adding a quantity of the halide salt to the anolyte; or (iii) both (i) and (ii).

10 . The electrowinning process of claim 1 , wherein the metal ore particles are obtained from a metal ore feedstock further comprising aluminates, silicates, or aluminates and silicates, the method further comprising leaching at least a portion of the aluminates, silicates, or aluminates and silicates from the metal ore feedstock by contacting the metal ore feedstock with a hydroxide solution to provide the metal ore particles.

11 . The electrowinning process of claim 10 , wherein the hydroxide solution is a spent catholyte obtained from the electrochemical cell after applying the voltage across the electrochemical cell.

12 . The electrowinning process of claim 1 , wherein the anolyte comprises concentrated seawater having a halide salt concentration of from 10 wt % to 50 wt %.

13 . The electrowinning process of claim 1 , wherein:
providing the electrochemical cell further comprises providing a cell stack comprising
(i) a number of the electrochemical cells, a cathode electrical connector connecting cathodes of each of the electrochemical cells in parallel, an anode electrical connector connecting anodes of each of the electrochemical cells in parallel, and a voltage source electrically connected to the cathode electrical connector and the anode electrical connector, or
(ii) a number n of the electrochemical cells, a number n−1 of conductive bipolar plates wherein a conductive bipolar plate is positioned between each adjacent pair of electrochemical cells, a cathode electrical connector connected to a cathode of a first electrochemical cell in the series, an anode electrical connector connected to an anode of a last electrochemical cell in the series, and a voltage source electrically connected to the cathode electrical connector and the anode electrical connector;
providing the catholyte further comprises providing the catholyte within each electrochemical cell of the cell stack; providing the anolyte within the anode compartment further comprises providing the anolyte within each electrochemical cell of the cell stack; and applying a voltage across the electrochemical cell further comprises applying the voltage across the cell stack to effect reduction of the M x O y in each cathode compartment to provide the metal M and formation of Cl 2 gas in each anode compartment.

14 . The electrowinning process of claim 1 , wherein:
(i) the voltage applied is from 2 V to 5 V per electrochemical cell; or (ii) the electrochemical cell or cell stack is operated at a current density of from 20 mA cm −2 to 500 mA cm −2 ; or (iii) the electrochemical cell or cell stack is operated at a temperature from 25° C. to 150° C.; or (iv) any combination of (i), (ii), and (iii).

15 . An electrochemical cell, comprising:
a cathode comprising low-carbon steel, copper, iron, graphite, vitreous carbon, or titanium; an anode comprising an oxide coating comprising Ru, Pt, Ir, or any combination thereof, on a conducting substrate; and a separator between the cathode and the anode, the separator comprising a cation-selective membrane that is permeable to alkali metal cations, alkaline earth metal cations, or a combination thereof.

16 . The electrochemical cell of claim 15 , further comprising:
a second anode; and a second separator between the cathode and the second anode, the second separator comprising a cation-selective membrane that is permeable to alkali metal cations, alkaline earth metal cations, or a combination thereof.

17 . The electrochemical cell of claim 15 , further comprising:
(i) gas collecting means for collecting gas generated at the anode; or (ii) gas collecting means for collecting gas generated at the cathode; or (iii) a magnet operable to be passed over a surface of the cathode; or (iv) a catholyte mixing means and an anolyte mixing means; or (v) a voltage source electrically connected to the cathode and the anode; or (vi) any combination of two or more of (i), (ii), (iii), (iv), and (v).

18 . The electrochemical cell of claim 15 , further comprising:
a catholyte comprising (i) water, (ii) a metal hydroxide comprising Q, where Q is an alkali metal, an alkaline e

Assignees

• Univ Oregon

Inventors

• Kempler Paul
• Konovalova Anastasiia
• Boettcher Shannon W
• Noble Berkley B

Classifications

• C25C7/06

  Operating or servicing · CPC title

• C25C7/02

  Electrodes (consumable anodes for the refining the metals C25C1/00 - C25C5/00); Connections thereof · CPC title

• C25C7/04

  Diaphragms; Spacing elements · CPC title

• C25B1/16

  Hydroxides (by simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine C25B1/34) · CPC title

• C25C1/02

  of light metals · CPC title