Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B35/00—Boron; Compounds thereof
  • C01B35/08—Compounds containing boron and nitrogen, phosphorus, oxygen, sulfur, selenium or tellurium
  • C01B35/10—Compounds containing boron and oxygen
  • C01B35/1045—Oxyacids
  • C01B35/1054—Orthoboric acid
  • C01B35/1081—Preparation by working up other natural sources, e.g. seawater
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D15/00—Lithium compounds
  • C01D15/04—Halides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
  • C01D3/00—Halides of sodium, potassium or alkali metals in general
  • C01D3/04—Chlorides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F11/00—Compounds of calcium, strontium, or barium
  • C01F11/46—Sulfates
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
  • C01F5/00—Compounds of magnesium
  • C01F5/26—Magnesium halides
  • C01F5/30—Chlorides

Definitions

• the present invention relates to a process for the enrichment of lithium with simultaneous depletion of magnesium from solutions of chloridic nature, which have high magnesium contents in relation to the lithium content.
• the currently known, largest resources of lithium are in the form of aqueous solutions (brines) in dried or partially dried salt lakes in South America, Asia and Africa.
• the solutions are mostly saturated NaCl solutions with varying concentrations of the ions K + , Mg ++ , Li + and SO 4 ⁇ as well as borate.
• the concentration for Li + is usually in a range between 200-4000 ppm.
• K + , Mg ++ and SO 4 ⁇ the concentrations reach into the tens of gram range.
• the solutions are z.
• evaporation basins or other technical equipment for fermentation (as in DE 10 2009 006 668.3).
• most of the salts are usually separated in the approximate sequence NaCl, KCl and, depending on the specific composition of the brine, various sulfates of the alkali metal magnesium sulfates.
• the most soluble salts LiCl and MgCl 2 continue to accumulate in the solution.
• the last parts of K + are crystallized on further evaporation as carnallite until finally bischofite, MgCl2 * 6H 2 O is deposited.
• magnesium hydroxide Mg (OH) 2
• Mg (OH) 2 these magnesium hydroxide precipitates occurring both partially in the evaporation basins and in the processing tanks. could be done in the factory.
• the solution for precipitating the magnesium hydroxide may also contain sodium carbonate.
• Li + is tried directly from the solutions by specific adsorption or ion exchange on granules or tablets based on (Al (OH) 3 (US Pat. No. 5,389,349, US Pat. No. 6,280,693 B1), certain types of manganese oxides, such as ⁇ type [Sagara, F., Ning, WB, Yoshida, I., Ueno, K., Separately See Technol. 24 (1989), 1227-1243; Chitrakar, R., Kanoh, H., Miyai, Eng. Chem. Res. 40 (2001), 2054-2058] or titanic acids [Yawata, K., Res. Rep.
• ⁇ type Sagara, F., Ning, WB, Yoshida, I., Ueno, K., Separately See Technol. 24 (1989), 1227-1243; Chitrakar, R., Kanoh, H., Miyai, Eng. Chem. Res. 40 (2001
• Ion exchange resins for Li separation have also been proposed instead of the inorganic sorbents [Bauman, WC, "Structure and Operation of DOW's New Lithium Selective Ion-Exchange Resin", in “Lithium - Current Applications in Science, Medicine and Technology”, J. Wiley and Sons, 1985].
• ion exchange resins can be better cut with respect to lithium ion selectivity, they are often more expensive than the abovementioned sorbents.
• the object of the invention is therefore a method that allows the accumulation of lithium and the separation of companion salts without lithium loss.
• the object is achieved by a process for the depletion of magnesium and enrichment of lithium in chloride salt solutions, in which the further evaporated solution is added with minimum contents of 4 g / L Li + and 60 g / L Mg 2+ KCl, which with the MgC of the solution is at least partially converted to carnallite (Kaliunncarnallit) and deposited in the form of Kaliunncarnallit, wherein the added KCI amount is such that the composition of the mother solution in the vicinity of the saturation of carnallite (Kaliunncarnallit) and KCl is adjusted and thus the formation of lithium carnallite is avoided.
• composition of the mother solution sets in the vicinity of the saturation of Kaliunncarnallit and KCl, means that the mother solution has taken according to their temperature, the maximum amount of KCL and thus the preferred deposit Kaliunncarnallit is secured against lithium carnallite.
• the solution in the presence of KCl, the solution can be further evaporated until a sufficiently high Li: Mg mass ratio is achieved.
• Li: Mg mass ratios of up to 7: 1 can be achieved in this way.
• the KCl is fed gradually or continuously to the evaporator.
• the addition of the KCl can be carried out periodically or continuously, just as the carnallite can be separated off in one or more stages or can also be made continuous.
• the actual design depends essentially on the mass ratio of potassium carnallite to be formed and the remaining volume of mother solution resulting for a desired Li: Mg ratio.
• the KCl is added in solid form, as an aqueous suspension with optionally further dissolved salts such as NaCl or MgC or as a homogeneous saturated solution.
• the KCl may be in solid form, preferably fine-grained, metered or in a thick aqueous suspension, which may contain besides water also other for LiCI separation less disturbing components such as NaCl, MgC or some sulfate.
• a homogeneous saturated or nearly saturated aqueous solution of KCl is also applicable.
• the time of KCI addition in the process can be chosen differently, but should be at least shortly before reaching saturation of lithium carnallite in the mother liquor.
• KCl is added after the evaporation of the desired amount of water.
• the evaporation can be carried out according to this variant, first at elevated temperature to the desired degree of concentration and then added KCl and cooled after a certain period of time for the Liereretress and as described above potassium carnallite are separated.
• the potassium carnallite which forms is discharged stepwise or continuously from the solution to the evaporator by means of solid-liquid separation.
• solid-liquid separation filtration with vacuum or overpressure or centrifugation or a combination of methods is used.
• the potassium carnallite separation takes place at temperatures of 15 to 60 ° C, preferably at 15 to 40 ° C.
• the suitable temperature for carnallite separation is preferably the ambient temperature.
• the deposition of magnesium chloride in the form of potassium carnallite has the further advantage that the morphology of the carnallite crystals for a solid-liquid separation is more favorable than that of bishopite and less mother solution sticks to the solid-liquid separation.
• solutions close to the compositions of simultaneous saturation of potassium carnallite and KCl, at a given LiCl concentration have higher vapor pressures and lower viscosities than solutions at higher MgC.sub.x concentrations necessary for bischofite deposition.
• the precipitated and discharged potassium carnallite can be broken down into KCl and a concentrated MgC ⁇ solution by using water or a relatively dilute MgCl solution by known methods.
• this carnallite decomposition will be carried out at ambient temperature.
• the KCl used for MgC ⁇ enrichment recovered back and can be used again for the inventive method.
• potassium carnallite precipitates on the basis of corresponding potassium contents of the starting solutions in upstream process steps, it can be included in the decomposition process of the KCI recovery and the excess KCl can be discharged from the process and further processed into a salable product.
• KCl is recovered in the process step of Carnallitzermaschine on the recovery of the KCl by incurred from other process steps potassium carnallite and / or KCI-containing fractions are included.
• the inventive method for depletion of magnesium and enrichment of lithium is an essential step in the production of concentrated lithium solutions of solutions of natural Li-containing salt deposits (Brines).
• the solutions are mostly saturated NaCl solutions with varying concentrations of the ions K + , Mg ++ , Li + and SO 4 ⁇ as well as borate.
• the concentration for Li + is usually in a range between 200-4000 ppm.
• K + , Mg ++ and SO 4 ⁇ the concentrations reach into the tens of gram range.
• Concentrated lithium solutions are prepared by the process according to the invention from such solutions with the following steps: a) separation of NaCl and KCl by evaporation,
• a concentration is carried out by evaporation.
• KCl can then be added in several stages, further evaporated and the crystallizing carnallite separated from the mother liquor by a suitable solid-liquid separation method (filtration, centrifugation).
• the Li: Mg ratio has then typically increased to about 3: 1, with Li + concentrations in the range of 20-60 g / L.
• the carnallite is washed with a small amount of water or a suitable process solution in order to remove most of the LiCI adhering to the mother liquor. before being sent to KCI recovery for decomposition. The washing solution is recycled in the process stages located further up.
• the highly concentrated LiCl solution is then subjected to a fine cleaning, in particular to the remaining magnesium removal by adding NaOH, if appropriate also containing Na 2 CO 3, in order then to precipitate with soda U 2 CO 3.
• the LiCl solution can be directly further evaporated to crystallize LiCl hydrate or LiCl.

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• 2010
  • 2010-05-05 DE DE201010019554 patent/DE102010019554B4/de not_active Expired - Fee Related
• 2011
  • 2011-05-05 CN CN201180022561.6A patent/CN103038170B/zh not_active Expired - Fee Related
  • 2011-05-05 WO PCT/EP2011/057194 patent/WO2011138389A1/de active Application Filing
• 2012
  • 2012-10-30 CL CL2012003052A patent/CL2012003052A1/es unknown

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Non-Patent Citations (10)

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