Preparation method for lithium phosphate, preparation method for lithium hydroxide, and preparation method for lithium carbonate
The present invention relates to a method for producing lithium phosphate, comprising: passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent, passing the distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution, and putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate.
1. A method for producing lithium phosphate, comprising:
passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent;
passing distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution;
putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate;
removing impurities in the lithium-containing desorption solution before the step of putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate,
wherein the concentration of lithium comprised in the lithium-containing desorption solution is in the range of 0.8 g/L to 1.5 g/L.
2. The method of claim 1 , wherein
the step of removing impurities in the lithium-containing desorption solution comprises
separating the impurities physically by passing the lithium-containing desorption solution through a filtration membrane having different permeability of monovalent ions and divalent ions;
putting a precipitant in the lithium-containing desorption solution to remove impurities; or
removing impurities by electrodialysis method using a monovalent cation selective permeable membrane.
3. The method of claim 1 , wherein
the impurities to be removed in the step of removing impurities are divalent cations.
4. The method of claim 3 , wherein
the divalent cation comprises at least one of calcium, magnesium and strontium.
5. The method of claim 2 , wherein
the precipitant put in the step of removing impurities is at least one of sodium hydroxide (NaOH), sodium carbonate (Na 2 CO 3 ), calcium hydroxide (Ca(OH) 2 ), sodium sulfate (Na 2 SO 4 ), ammonium hydroxide (NH 4 OH), ammonium carbonate ((NH 4 ) 2 CO 3 ), ammonium sulfate ((NH 4 ) 2 SO 4 ) and potassium hydroxide (KOH).
6. The method of claim 2 , wherein
the precipitant put in the step of removing impurities is sodium carbonate (Na 2 CO 3 ).
7. The method of claim 2 , wherein
the content of the precipitant put in the step of removing impurities is in the range of 1 equivalent to 2 equivalents on the basis of the equivalent of the impurity ions.
8. The method of claim 1 , further comprising
using electrodialyser to concentrate the lithium-containing desorption solution; or
concentrating the lithium-containing desorption solution using a reverse osmosis method; before the step of putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate.
9. The method of claim 8 , wherein
the electrodialyser comprises a cathode cell comprising a cathode separation membrane, an anion selective-type permeable membrane which is selectively permeable to anions, a cation selective-type permeable membrane which is selectively permeable to cations, and an anode cell comprising an anode separation membrane are disposed in a sequential order.
10. The method of claim 8 , wherein
the concentration of lithium which is concentrated is 1 g/L to 15 g/L.
11. The method of claim 1 , wherein
in the step of putting a phosphorous supplying material in the lithium-containing desorption solution to obtain lithium phosphate;
a pH adjusting agent is added together with the phosphorus supplying material.
12. The method of claim 1 , wherein
the concentration of lithium in the lithium-containing solution is 0.1 g/L to 2.0 g/L.
13. The method of claim 1 , wherein
the aluminum-based adsorbent comprises an adsorbent powder and a binder.
14. The method of claim 1 , wherein
the aluminum-based adsorbent comprises aluminum hydroxide.
15. The method of claim 1 , wherein
the step of obtaining the lithium-containing desorption solution is
performed by passing the distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through a content of 0.5 to 10 times on the basis of the volume of the aluminum-based adsorbent on which the lithium is adsorbed.
16. The method of claim 15 , wherein
in the step of obtaining the lithium-containing desorption solution,
the lithium-containing desorption solution obtained by passing the distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through a content of 0.5 to 3 times on the basis of the volume of the aluminum-based adsorbent on which the lithium is adsorbed is used in subsequent process,
and the desorption solution used more than 3 times is reused for next desorption of the lithium adsorbent.
17. The method of claim 8 , wherein
the step of using electrodialyser to concentrate the lithium-containing desorption solution; is performed 2 times or more.
18. A method for producing lithium hydroxide, comprising:
passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent;
passing distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution; and
injecting the lithium-containing desorption solution into a bipolar electrodialyser to obtain an aqueous solution of lithium hydroxide,
wherein the concentration of lithium comprised in the lithium-containing desorption solution is in the range of 0.8 g/L to 1.5 g/L.
19. A method for producing lithium carbonate, comprising:
passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent;
passing distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution;
injecting the lithium-containing desorption solution into a bipolar electrodialyser to obtain an aqueous solution of lithium hydroxide; and
carbonating the obtained aqueous solution of lithium hydroxide to obtain lithium carbonate,
wherein the concentration of lithium comprised in the lithium-containing desorption solution is in the range of 0.8 g/L to 1.5 g/L.
20. A method for producing lithium carbonate, comprising:
passing a lithium-containing solution through an aluminum-based adsorbent to adsorb lithium on the aluminum-based adsorbent;
passing distilled water or an aqueous solution having a lower lithium concentration than the lithium-containing solution through the aluminum-based adsorbent on which the lithium is adsorbed to obtain a lithium-containing desorption solution; and
carbonating the desorption solution to obtain lithium carbonate,
wherein the concentration of lithium comprised in the lithium-containing desorption solution is in the range of 0.8 g/L to 1.5 g/L.