Method for improving lithium yield in a direct lithium extraction process
There is disclosed a method and apparatus for improving lithium yield of lithium lithium-selective media in one or more packed-bed columns in a direct lithium extraction process. The method comprises the steps of a) passing the lithium-selective media and a stream of process fluid through a screening zone; and b) collecting a portion of lithium-selective media having a required particle-size distribution and/or free of contaminants.
1 . A method for processing lithium-selective media in one or more packed-bed columns in a direct lithium extraction process, the method comprising the steps of:
a) unloading the lithium-selective media from one or more packed-bed columns;
b) passing the lithium-selective media and a stream of process fluid through a screening zone, wherein the screening zone comprises a first sieve element having a first mesh size of approximately 1.5 mm to 2.5 mm; and
c) collecting a first portion of the lithium-selective media having a particle-size no greater than the first mesh size, wherein the first portion of the lithium-selective media is separated from a second portion of the lithium-selective media having a particle-size larger than the first mesh size.
2 . The method according to claim 1 , the first mesh size is approximately 2.0 mm.
3 . The method according to claim 1 , wherein the screening zone further comprises a second sieve element having a second mesh size of approximately 0.05 mm to 0.6 mm; and further comprising a step of collecting lithium-selective media having a particle-size that is no greater than the first mesh size and no smaller than the second mesh size.
4 . The method according to claim 1 , further comprising, prior to step (a), an additional step of identifying one or more of (i) a poor flow distribution through the one or more packed-bed columns; (ii) a high pressure drop through the one or more packed-bed columns; (iii) a deterioration in lithium purity of an eluate stream from the one or more packed-bed columns; and (iv) presence of a contaminant.
5 . The method according to claim 1 , further comprising an additional step (ed) of loading the lithium-selective media into the one or more packed-bed columns.
6 . The method according to claim 1 , wherein the lithium-selective media is an ion sieve adsorbent, a lithium-metal oxide adsorbent, a mixed metal oxide adsorbent, an alkali or alkali earth metal/alumina matrix, transition metal/alumina matrix or a molecular sieve adsorbent.
7 . The method according to claim 1 , wherein the screening zone has a sieving capacity of at least 1 m 3 /hour of lithium-selective media and a targeted separation of >90%, as measured by a percentage of particles having a size that meets the required particle size distribution.
8 . The method according to claim 1 , wherein the process fluid is water, pH adjusted water, salt water, a polar organic solvent or derived from the direct lithium extraction process.
9 . The method according to claim 8 , wherein the water is distilled water, reverse-osmosis process-recycled water or derived from an external source.
10 . The method according to claim 1 , wherein the process fluid for removing the contaminant is surfactant-based, a coagulant, a flocculant, hydrocarbon based, pH adjusted water, or a gas.
11 . The method according to claim 10 , wherein the process fluid is single-phase or multi-phase.
12 . The method according to claim 2 , further comprising an additional step of dewatering one or more of the first portion of the lithium-selective media and the second portion of the lithium-selective media.
13 . The method according to claim 12 , wherein the one or more of the first portion of the lithium-selective media and the second portion of the lithium-selective media is pumped as a slurry to a water collection tank for the dewatering step.
14 . The method according to claim 13 , wherein water obtained from the dewatering process is filtered and returned to the direct lithium extraction process.
15 . The method according to claim 3 , wherein the second mesh size is approximately 0.1 mm.