Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
  • B01D61/46—Apparatus therefor
  • B01D61/463—Apparatus therefor comprising the membrane sequence AC or CA, where C is a cation exchange membrane
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
  • B01D61/42—Electrodialysis; Electro-osmosis ; Electro-ultrafiltration; Membrane capacitive deionization
  • B01D61/44—Ion-selective electrodialysis
  • B01D61/46—Apparatus therefor
  • B01D61/48—Apparatus therefor having one or more compartments filled with ion-exchange material, e.g. electrodeionisation
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D15/00—Lithium compounds
  • C01D15/02—Oxides; Hydroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D15/00—Lithium compounds
  • C01D15/08—Carbonates; Bicarbonates
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
  • C01D5/06—Preparation of sulfates by double decomposition

Definitions

• the present invention describes a process to produce lithium chemical compounds, such as lithium hydroxide, bicarbonate or carbonate, using electrodialysis, which involves ion exchange between lithium sulfate solution (Li 2 S0 4 ) and sodium hydroxide solution (NaOH), sodium bicarbonate (NaHCOs) or sodium carbonate (Na 2 C0 3 ).
• the invention relates to an apparatus for performing out the method.
• Lithium hydroxide, lithium bicarbonate, or lithium carbonate are prepared by reacting lithium sulfate (L1 2 SO4) with any of the following species: sodium hydroxide (NaOH), sodium bicarbonate (NaHCOs), or sodium carbonate (Na 2 C0 3 ). Reactions are based on the following chemical equations:
• the first production option is double replacement reaction: chemical compound solutions are mixed in a reactor where they react together to precipitate the solid product, such as Li 2 C0 3 , using controlled heating and cooling and also neutralization principle.
• the solid product such as Li 2 C0 3
• Such a technical approach is the subject of the Chinese patent CN 1486931.
• the disadvantages of the said process are level of conversion, the formation of solid deposits on the reactor surface during crystallization, and the need to refine the product to a level of applicability for batteries like battery grade lithium carbonate.
• Electrodialytic concentrating lithium salt from primary resource where a concentrated lithium sulfate solution is mixed in a sodium carbonate solution in a reactor.
• bipolar electrodialysis driving force is the DC voltage.
• the cation exchange membranes, the bipolar membranes, and optionally the anion exchange membranes are in the electrodialysis stack.
• Lithium hydroxide is formed, and the principle of bipolar electrodialysis function also forms the corresponding acids like sulfuric, hydrochloric, or nitric.
• the lithium hydroxide production process is optimized according to the source of the raw material, such as salt lakes, or the hydrometallurgical treatment of the batteries.
• Electrodialysis metathesis method described in this invention helps to overcome the above-mentioned drawbacks of different electrodialysis concepts while maintaining the progressive features of the process for producing lithium chemical compounds such as lithium hydroxide, bicarbonate or carbonate.
• the invention involves the exchange of ions between the lithium sulfate solution (Li 2 S0 4 ) and the sodium hydroxide solution (NaOH), primary sodium bicarbonate (NaHCCb) or sodium carbonate (Na 2 COs), which takes place in an electric field on an ion exchange membrane system containing at least one anion exchange membrane and cation exchange membranes.
• the repeating sequence of ion exchange membranes form at least four intermembrane spaces.
• the basic repeating motif is visualized in Figure lb by hatching.
• the ions forming the main product are passing through the P-labeled membranes (see Figs la and lb).
• Lithium-ion is passing the cation exchange membrane CMP forming the main product.
• the hydroxide, bicarbonate or carbonate anions are passing anion exchange membrane AMP forming the main product.
• the sodium and sulfate ions are passing through the O-labeled membranes.
• ions are forming the by-product sodium sulfate solution stream after recombination - specifically through the cation exchange membrane CMO forming by-product cation and through the anion exchange membrane AMO forming by-product sulfate anion.
• a cation exchange membrane terminates the basic repeating motif including the four intermembrane spaces Cl, Dl, C2, D2. Source and product chemical compounds solutions flow on both sides of the membranes in the intermembrane compartments Cl, Dl, C2, D2.
• a solution of the by-product flows in the first intermembrane space Cl, from the positive electrode - anode + by interposing the first cation exchange product CMO forming the byproduct and the first anion-exchange AMO forming the by-product.
• the primary anion source solution e.g., sodium hydroxide, bicarbonate, and sodium carbonate flow in the fourth intermembrane space D2 from the positive electrode (anode +), between the second anion exchange membrane AMP forming the main product and the cation exchange membrane CMO forming by-product.
• a primary cation source solution e.g., lithium sulfate solution flows in the second intermembrane space Dl from the positive electrode (anode +), between the first anion exchange membrane AMO forming the by-product and the second cation exchange membrane CMP forming the main product.
• the concentration of the lithium sulfate, sodium hydroxide, primary source sodium bicarbonate, or sodium carbonate feed solutions is preferably in the range from 0.1 to 1.0 mol/L.
• the concentration of the obtained product solutions - sodium sulfate, lithium hydroxide, lithium bicarbonate, or lithium carbonate is higher than 0.1 mol/L.
• the temperature of the solutions in operation is preferably in the range from 10 to 60 °C, preferably in the range from 20 to 50 °C. Their solubility limits the final salt solution concentration.
• the apparatus for carrying out the method of the present invention is comprised of electrodes, between which an array of ion exchange membranes is included containing at least one sequence of anion exchange membranes AMP, AMO and cation exchange membranes CMP, CMO, alternating and forming at least four intermembrane spaces Cl, Dl, C2, D2 for solutions of input and output chemical compounds of electrodialysis double replacement reaction ion exchange system.
• the ion exchange membranes are preferable of the homogeneous or heterogeneous type in thickness from 0.1 to 1.0 mm and with a permselectivity more than 90%.
• Membrane spacers thickness is between 0.1 to 2.0 mm, and distributors are made from polymeric material providing solution equal distribution, source, and product solution mutual immiscibility and mechanical support of the intermembrane spaces.
• the voltage between the electrodes is preferably from 1.0 to 2.5 V per sequence of four membranes - a membrane quadruplet at a current density in the range from 30 to 300 A/m 2 .
• the main advantage of the lithium bicarbonate production using electrodialysis metathesis double replacement reaction process according to the invention is obtaining a straightforward first product solution - e.g., L1HCO3, which meets the purity application limits in batteries, at a high conversion rate.
• the conversion itself takes place in an electrodialysis device made of non-corrosive polymeric materials.
• the benefit of this technical solution is the preparation of a high concentration lithium bicarbonate/carbonate solution near saturation limit with very high purity for use in batteries.
• An analogy of the Solvay process used in the production of sodium carbonate can be utilized for the further production of a commodity chemical like Li 2 C0 3 . Formed lithium bicarbonate formed is converted to lithium carbonate by heating (calcination).
• Fig. la is a schematic diagram of an electrodialysis metathesis double replacement reaction method for producing lithium hydroxide, lithium bicarbonate or lithium carbonate by using one (simplest) ion exchange membrane sequence;
• Fig. lb is a representation of an electrodialysis metathesis double replacement reaction method basic repeating motif for producing lithium hydroxide, lithium bicarbonate, or lithium carbonate using one (hatched) ion exchange membrane sequence and one ending cation exchange membrane CMO;
• Figure 2 shows an exemplary arrangement of five series of four membranes - membrane quadruplets.
• the electrodialysis laboratory unit P EDR-Z/4x (producer company MemBrain) in electrodialysis-metathesis configuration was used for testing.
• the unit contained 5 tanks with a volume of 0.25 to 2.0 liters and 5 centrifugal pumps with a magnetic insert for circulation of solutions in the intermembrane spaces Cl, C2, Dl, D2 created by the anion exchange membranes of AMP, AMO and cation exchange membranes CMP, CMO (scheme of one primary sequence - see Figure lb) and also for electrode rinsing solution E.
• Electrode solution - sodium sulfate solution (Na 2 S0 4 ).
• EDM module was equipped with eleven pcs of cation exchange membranes RALEX ® (CM-PP) and with ten pcs of anion exchange membranes RALEX ® (AM-PP), alternating and forming five membrane sequences (quadruplets) - see scheme in Figure 2.
• CM-PP cation exchange membranes
• AM-PP anion exchange membranes
• Each of the membrane repeating sequence had the arrangement of the hatched part from Figure lb.
• One active membrane area was 64 cm 2 . The test was performed in a batch process.
• the EDM solutions were circulated at 0.5 L/min, and the temperature was kept at 30 °C.
• the working voltage was in the range from 6.7 to 12.0 V and the current was set at 1.28 A.
• 1000 mL of L1HCO3 solution main product was obtained in the third intermembrane space C2 of with concentration 0.69 mol/L and 1100 ml of the secondary product Na 2 S0 4 in the first intermembrane space Cl with concentration 0.38 mol/L in this design of experiment.
• the main product was dosed with demineralized water to prevent precipitation by reaching the solubility level.
• the sulfur content in the main product was 0.115 g/L, and the lithium content was 4.78 g/L.
• the product purity in terms of the molar content of lithium in the numerator relative to the sum of lithium and sulfur in the denominator was 99.5%.
• a sodium sulfate solution with 0.07 mol/L concentration was circulated in the electrode chambers during the experiment.
• Lithium chemical compounds production like lithium hydroxide, bicarbonate, or carbonate which are widely used in the battery industry.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Water Supply & Treatment (AREA)
• Inorganic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Urology & Nephrology (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Separation Using Semi-Permeable Membranes (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)

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• 2018
  • 2018-05-29 CZ CZ2018-250A patent/CZ308122B6/cs unknown
• 2019
  • 2019-05-24 EP EP19750051.5A patent/EP3801842A2/en active Pending
  • 2019-05-24 WO PCT/CZ2019/050025 patent/WO2019228577A2/en not_active Ceased
  • 2019-05-24 CN CN201980035434.6A patent/CN112218704B/zh active Active

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