Method for recycling lithium in lithium iron phosphate through electrochemical method

[0025] Step 1: Use lithium iron phosphate as the positive electrode sheet, sodium chloride aqueous solution as the electrolyte, graphite as the negative electrode, and apply a 0.1V electric potential to it in an electrolytic cell for electrochemical recovery. The concentration of the sodium chloride solution is 0.025mol / L, the time is 2h, the lithium ions in the positive electrode sheet migrate into the electrolyte solution to form a lithium-containing solution. A lithium-containing solution is obtained. After the experiment is over, the lithium content in the positive electrode sheet is detected, the migration rate of lithium can reach 95.3%, and the lithium content in the lithium-containing solution is detected, which is 1.1g / L (with Li 2 O meter).

[0026] Step 2: Concentrate the lithium-containing solution obtained in step 1 to Li 2 A solution with an O content of 33g / L, to which 280g / L Na is added 2 CO 3 , The excess coefficient is 105%, and the precipitation of lithium carb...

[0028] Step 1: Use the lithium iron phosphate material as the positive electrode sheet, the lithium sulfate aqueous solution as the electrolyte, and the copper sheet as the negative electrode, and apply a 0.3V potential to it in an electrolytic cell for electrochemical recovery. The concentration of the lithium sulfate solution is 0.5mol / L, the time is 1.5h, the lithium ions in the positive electrode sheet migrate into the electrolyte solution to form a lithium-containing solution. After the experiment is over, the lithium content in the positive electrode sheet is detected, the migration rate of lithium can reach 99.1%, and the lithium content in the lithium-containing solution is detected, which is 1.1g / L (with Li 2 O meter).

[0029] Step 2: Concentrate the lithium-containing solution obtained in step 1 to Li 2 A solution with an O content of 33g / L, to which 280g / L Na is added 2 CO 3 , The excess coefficient is 105%, and the precipitation of lithium carbonate is obtained. After...

[0031] Step 1: Using lithium iron phosphate as the positive electrode, lithium sulfate aqueous solution as the electrolyte, and copper as the negative electrode, apply a 1.2V potential to it in an electrolytic cell for electrochemical recovery, where the electrolyte concentration is 0.8 mol / L, the time is 5h, the lithium ions in the positive electrode sheet migrate into the electrolyte solution to form a lithium-containing solution. After the experiment is over, the lithium content in the positive electrode sheet is detected, the migration rate of lithium can reach 99.6%, and the lithium content in the lithium-containing solution is detected, which is 1.5g / L (with Li 2 O meter).

[0032] Step 2: Concentrate the lithium-containing solution obtained in step 1 to Li 2 A solution with an O content of 30g / L, to which 285g / L Na is added 2 CO 3 , The excess coefficient is 105%, and the precipitation of lithium carbonate is obtained. After the precipitation is completed for 20 minutes, t...