Process of recovery of base metals from oxide ores
A method for recovering base metal values from oxide ore is provided, where the ore includes a first group metal selected from nickel, cobalt and copper. The method includes reducing ore particle size to suit the latter unit operation, favoring contact for the metal elements, contacting the ore with ferric or ferrous chloride, hydrated or anhydrous, to produce a mix of ore and iron (II or III) chloride subjecting the mixture of the ore and ferric or ferrous chloride to enough energy to decompose the chlorides into hydrochloric acid and a iron oxides from the second group, forming their respective chlorides, selectively dissolve the produced base metal chlorides, leaving the metal as oxides and in the solid state, and recovering the dissolved base metal values from aqueous solution.
1. A process of recovery of base metals from an oxide ore including a first metal selected from the group consisting of iron, magnesium and aluminum, and a second metal selected from the group consisting of nickel, cobalt and copper, the process comprising:
contacting the oxide ore with at least one of ferric or ferrous chloride to form chlorides;
heating the mixture of the oxide ore and the at least one of the ferric or ferrous chloride to decompose the chlorides into hydrochloric acid and hematite;
contacting the hydrochloric acid with base metal oxides of the second metal included in the oxide ore to form second metal chlorides; and
selectively dissolving the second metal chlorides leaving first metal oxides in solid state,
wherein the oxide ore is stacked in a heap and leached with sulfuric acid at least one of prior to or during selective dissolution of the second metal chlorides.
2. The process according to claim 1 , wherein, before contacting the oxide ore with at least one of ferric or ferrous chloride, reducing ore particle size from about 2 mm to less than 0.5 mm.
3. The process according to claim 1 , wherein the ferric chloride is added in a ratio of between 0.05 and 1.5 times an oxide ore mass.
4. The process according to claim 1 , wherein the ferrous chloride is added in a ratio of between 0.05 and 1.5 times an oxide ore mass.
5. The process according to claim 4 , wherein an oxidizing agent is added to the oxide ore in a ratio between 0.0001 and 10 times the ore mass to react with the ferrous chloride.
6. The process according to claim 5 , wherein the oxidizing agent is selected from the group consisting of oxygen, potassium permanganate, ozone and hydrogen peroxide.
7. The process according to claim 1 , wherein the heating is performed at a temperature ranging from about 60° C. to about 600° C.
8. The process according to claim 1 , wherein heating is performed for a period of time ranging from about 0.5 hours to about 12 hours.
9. The process according to claim 1 , further comprising adding water during the heating of the mixture.
10. The process according to claim 9 , wherein the adding of the water further comprises a wet air injection.
11. The process according to claim 1 , wherein the step of leaching with sulfuric acid comprises increasing the sulfuric acid content by up to about 100 g/L and at a pH of between about 1 and about 3.
12. The process according to claim 1 , further comprising a solid-liquid separation step after selectively dissolving the second metal chlorides.
13. The process according to claim 12 , wherein tailings from the solid-liquid separation step are contacted with a high intensity magnetic field to separate the hematite.
14. The process according to claim 1 , further comprising:
regenerating ferric or ferrous chloride by contacting recycled hematite with hydrochloric acid by reusing the at least one of the ferric or ferrous chloride used to contact the oxide ore; and
when regenerating ferrous chloride, adding a reducing agent.
15. The process according to claim 14 , wherein the reducing agent comprises a metallic iron.
16. The process according to claim 1 , wherein before contacting the oxide ore with at least one of ferric or ferrous chloride, reducing ore particle size from about 2 mm to about 0.050 mm.
17. The process according to claim 1 , wherein the ferric chloride is added in a ratio of between 0.1 to 0.5 times the oxide ore mass.
18. The process according to claim 1 , wherein the ferrous chloride is added in a ratio of between 0.1 to 0.5 times the oxide ore mass.
19. The process according to claim 1 , wherein the heating is performed at a temperature ranging from about 100° C. to about 300° C.