System apparatus and process for leaching metal and storing thermal energy during metal extraction

Patent metadata

Field	Value
Publication number	US-10907238-B2
Application number	US-201514847068-A
Country	US
Kind code	B2
Filing date	Sep 8, 2015
Priority date	Sep 9, 2014
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

An environmentally friendly (e.g. no acid, base, or cyanide) system and process for large scale extraction of metal ion into aerobic molten salt (or ionic liquid) and the electrodeposition of metal (e.g. copper, gold, silver, etc.) from the metal ion dissolved in the molten salt. The non-volatile low vapor pressure liquid salt is reusable, and heat from the molten slag can heat the molten salts or ionic liquids. Another embodiment comprises a one-pot apparatus for the extraction of metal (e.g. copper) from metal earths and electrodepositing the metal using a low melting (209° C.) aerated Na—K—Zn chloride salt in which copper metal oxidizes and is converted to soluble copper chloride. When an electrical power supply is connected to the graphite vessel (cathode) and to copper rods in the melt (anodes), then the copper chloride is deposited as copper metal by electroreduction on the bottom of the graphite reaction vessel.

First claim

What is claimed is:

1. An environmentally friendly leaching process for extracting and depositing metals from ore and slag, the process comprising:
(a) passing a molten ore or slag through a heat exchanger to transmit heat from the molten ore or slag to the heat exchanger;
(b) heating a non-volatile low vapor pressure liquid with the heat exchanger;
(c) transmitting the heated non-volatile low vapor pressure liquid to an open air crucible;
(d) heating, mixing and dissolving ore or slag into the non-volatile low vapor pressure liquid in the open air crucible at a temperature of at least four hundred degrees Celsius, until the mixture is a liquid solution with metal ions and undissolved ore or slag, wherein said low vapor pressure liquid comprises aerated molten salts or ionic liquid;
(e) separating, using a filtration or decanting mechanism, said liquid solution from said undissolved ore or slag;
(f) transferring said liquid solution from the open air-crucible into an electrochemical reactor via the filtration or decanting mechanism, said electrochemical reactor comprising:
i. a high temperature resistant housing;
ii. a cathode electrode and an anode electrode connected to a direct current power supply on an upper end, and immersed in said liquid solution on a bottom end; and,
iii. one or more valves to drain said electrochemical reactor;

(g) applying a current between the cathode and anode electrode to electrify said liquid solution; and,
(h) electro-depositing metal onto the cathode electrode from the metal ions in the electrified liquid solution,
wherein the electro-deposited metal is retrievable via the one or more valves of the electrochemical reactor.

2. The environmentally friendly leaching process of claim 1 , wherein the low vapour pressure liquid is a molten salt comprising low viscosity NaCl—KCl—ZnCl 2 .

3. The environmentally friendly leaching process of claim 1 , wherein the metal is selected from the group consisting of copper, silver, and gold, and any combination thereof.

4. The environmentally friendly leaching process of claim 1 , further comprising recycling the electrified liquid solution by passing the electrified liquid solution through the heat exchanger comprising melted slag that re-heats the electrified liquid solution.

5. The environmentally friendly leaching process of claim 4 , further comprising recycling the heated electrified liquid solution by transporting it back to the open air crucible.

6. The environmentally friendly leaching process of claim 1 , wherein mixing the aerated molten salt in the open air container further comprises digesting and extracting metals from the ore or slag via oxidization of metal and metal sulphide to metal oxide, and converting the metal oxide into metal chloride.

7. An environmentally friendly leaching system for extracting and depositing metals from ore and slag, comprising:
a. a mixing crucible containing a first mixture of slag or ore with an aerobic low vapor pressure liquid comprising molten salt or ionic liquid;
b. a heat source for heating said first mixture;
c. a means for stirring said mixture;
d. a second mixture formed by the heating and stirring of said first mixture, said second mixture comprising a liquid solution and undissolved slag or ore, said liquid solution having metal ions separated from said slag or ore;
e. a filtration or decanting mechanism positioned beneath said mixing crucible and able to remove the undissolved slag or ore from the liquid solution;
f. an electro-chemical reactor able to conduct electro-deposition to deplete the liquid solution of metal, said electro-chemical reactor comprising:
i. a high temperature resistant, corrosion resistant crucible storing the liquid solution;
ii. a cathode electrode and an anode electrode connected to a direct current power supply on an upper end, and immersed in the liquid salt solution on a bottom end; and,
iii. one or more valves to drain the liquid solution depleted of metal from the electro-chemical reactor into a movable re-cycle tank after metal ions from said liquid solution are electro-deposited on said cathode electrode;

g. a movable re-cycle tank able to receive, store, and transport the metal depleted liquid solution back to a heat exchanger device to re-cycle the molten salt or ionic liquid within the metal depleted liquid solution; and,
h. a heat exchanger device able to transfer heat from a melted slag that exceeds one thousand degrees Celsius to the metal depleted liquid salt solution comprising recycled molten salt or ionic liquid.

8. The environmentally friendly leaching system of claim 7 , wherein the molten salt is low viscosity NaCl—KCl—ZnCl 2 .

9. The environmentally friendly leaching system of claim 7 , wherein the liquid salt solution is maintained at about four hundred to five hundred degrees Celsius in the electrochemical reactor.

10. The environmentally friendly leaching system of claim 7 , further comprising a granulation tank for storing melted slag from the heat exchanger device, wherein the granulation tank is connected to the mixing crucible to mix the melted slag with the re-cycled molten salt or ionic liquid.

11. The environmentally friendly leaching system of claim 7 , wherein the metal is selected from the group consisting of copper, silver, and gold, and any combinations thereof.

12. The environmentally friendly leaching system of claim 7 , wherein the mixing crucible is able to mix the aerated molten salt until the metal within the slag or ore is extracted via oxidization of metal and low-valency metal cations and metal sulphide to metal oxide and the exchange of the sulfide and oxide in metal sulphide to metal oxide by chloride, thereby converting into metal chloride.

13. The process of claim 1 , wherein the ore or slag being heated, mixed and dissolved into the non-volatile low vapor pressure liquid is granulated ore or granulated slag.

14. The process of claim 1 , wherein the heated non-volatile low vapor pressure liquid is transmitted to the open air crucible by way of a storage tank.

15. The process of claim 1 , further comprising,
(i) after passing the molten ore or slag through the heat exchanger, transmitting the molten ore or slag to a granulator;
(j) converting the molten ore or slag to a granulated ore or a granulated slag; and
(k) transmitting the granulated ore or the granulated slag to the open air crucible;
wherein (i)-(k) occur after (c) and prior to (d).

16. The process of claim 1 , wherein the electrochemical reactor further comprises a heating unit to heat the liquid solution.

17. The process of claim 1 , wherein the electrochemical reactor further comprises a pressure release mechanism.

Assignees

• Metox Pte Ltd
• Univ Arizona
• Metoxs Pte Ltd

Inventors

• Jalbout Abraham Fouad
• Godinez Andres
• Gervasio Dominic Francis
• Elsentriecy Hassan H

Classifications

• Y02P10/20

  Recycling · CPC title

• C22B4/08

  Apparatus ({C22B4/005 takes precedence; } electric heating elements H05B) · CPC title

• C25C3/34

  of metals not provided for in groups C25C3/02 - C25C3/32 · CPC title

• C22B11/04

  by wet processes (extraction of metal compounds by leaching in organic solutions C22B3/16; treatment or purification of solutions by liquid-liquid extraction C22B3/26) · CPC title

• C22B15/0065

  Leaching or slurrying (with organic compounds C22B3/16) · CPC title