Method and system for recovering metals from black mass
A process recovers metals from a black mass. The process includes the following steps in the following order: step (a) providing the black mass, which comprises Li; step (b) adding water to the black mass and creating a suspension of the black mass in the water; step (c) dosing ozone as an oxidant to the suspension while stirring the suspension; and step (d) filtering and separating a filtrate containing LiOH dissolved in water from a Li depleted residue of the black mass. In step (c), the suspension is stirred with a shear rate greater than 11000 s −1 within the suspension.
1. A process for recovery of metals from a black mass, the process comprising the following steps in the following order:
step (a) providing the black mass, which comprises Li;
step (b) adding water to the black mass and creating a suspension of the black mass in the water;
step (c) dosing ozone as an oxidant to the suspension while stirring the suspension; and
step (d) filtering and separating a filtrate containing LiOH dissolved in water from a Li depleted residue of the black mass
wherein in step (c), the suspension is stirred with a shear rate greater than 11,000 s-1 within the suspension,
wherein the process further comprises, in a step (e), leaching the Li depleted residue of step (d) in an acidic leach, wherein at least one acid is added and the pH value is dropped below pH 3,
wherein the process further comprises:
adding a calcium source to the leachate or the suspension of step (e); and
in a step (f), filtering the suspension, and
wherein the process further comprises,
in a step (g), dosing ozone as an oxidant to the filtrate of step (f) while stirring, maintaining a pH value in the range of 2 to 4, and filtering the resulting suspension.
2. The process according to claim 1 , wherein:
in step (c), the suspension is stirred with the shear rate greater than 25,000 s-1 within the suspension.
3. The process according to claim 1 , wherein:
step (c) is performed for at least three hours.
4. The process according to claim 1 , wherein:
in step (c), ozone is dosed to the suspension with a rate of at least 0.1 gram (O 3 )/hour/gram (black mass) or with a maximum rate of 2 gram (O 3 )/hour/gram (black mass).
5. The process according to claim 1 , wherein:
in step (c), the temperature of the suspension is in the range from 70° C. to 95° C.
6. The process according to claim 1 , wherein:
in step (c), the suspension of the black mass in the water has a pH value in the range between 6 to 8.
7. The process according to claim 1 , the process further comprising:
adding an acid to the suspension in step (b) or step (c); and
dropping the pH value of the suspension to a pH value in the range between 3.5 and 4.5.
8. The process according to claim 7 , the process further comprising:
after step (c), adding a caustic; and
raising the pH value of the suspension before step (d) or raising the pH value of the filtrate of step (d) to a pH value higher than 6.
9. The process according to claim 1 , the process further comprising:
evaporating at least 20 vol % of the filtrate containing LiOH dissolved in water.
10. The process according to claim 1 , comprising:
precipitating lithium hydroxide (LiOH) from the filtrate containing LiOH dissolved in water by evaporation or crystallization.
11. The process according to claim 1 , the process further comprising:
adding one of the following additives to the filtrate containing LiOH dissolved in water:
a phosphate source and precipitating lithium phosphate (Li 3 PO 4 ); or
a carbonate source and precipitating lithium carbonate (Li 2 CO 3 ).
12. The process according to claim 10 , the process further comprising:
adding a caustic to the filtrate containing LiOH dissolved in water.
13. The process according to claim 10 , the process further comprising:
filtering the precipitated lithium hydroxide (LiOH) out; and
recirculating the filtrate back to the suspension of the black mass and the water in step (b) or (c).
14. The process according to claim 13 , the process further comprising:
bleeding the recirculated filtrate periodically.
15. The process according to claim 1 , the process further comprising:
adding a reductant to the acidic leach step (e).
16. The process according to claim 1 , the process further comprising:
in a step (h), adding sulfuric acid (H 2 SO 4 ) to the filtrate of step (g); and
raising the sulfuric acid (H 2 SO 4 ) concentration to at least 500 g/L to crystallize Ni-sulfate.
17. The process according to claim 11 , the process further comprising:
filtering the precipitated lithium phosphate (Li 3 PO 4 ) or lithium carbonate (Li 2 CO 3 ) out; and
recirculating the filtrate back to the suspension of the black mass and the water in step (b) or (c).