JPS644968B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has higher purity than resin/aluminate composites.
It concerns a method for obtaining Li ⁺ solutions, in particular lithium halide solutions. US Patent No. 4116856; 4116858;
and No. 4159311 contains crystalline LiX・2Al.
(OH) ₃ , where X is a halide, particularly a chloride, methods for making and using ion exchange resins are disclosed. When adsorption treatment is performed using a resin/aluminate composite to separate the lithium component dissolved in brine, Li ⁺ ions are selectively incorporated into the aluminate crystals, but at this time Li ⁺ ions are not already adsorbed. Some leftover brine remains in the interstices of the composite. If the brine contains other metal ions (i.e. ions other than alkali metals, such as alkaline earth metal ions), the desired Li ⁺ ions (hereinafter sometimes abbreviated as Li ⁺ ) are then eluted from the crystal. When washing with water is performed to remove the ions, these other ions, which were not present in the crystal structure but in the interstices, will also be included in the effluent. The use of a concentrated pure sodium halide brine wash prior to the water wash step used for Li ⁺ leaching ensures that there is no appreciable leaching of Li ⁺ in the aluminate crystals and that other metal ions (e.g. alkaline It has now been discovered that this results in the washing out of earth metal ions).
Therefore, when water is then used for leaching Li ⁺ in aluminate crystals, the only other metal ions present in appreciable amounts in the effluent are those of the sodium halide brine. As described above, the present invention uses a resin/aluminate composite that adsorbs and retains Li ⁺ ions and also contains brine contaminated with metal ions other than alkali metal ions.
A concentrated, relatively pure alkali metal halide solution, such as sodium halide brine, is used as a pre-wash before leaching the Li ⁺ with water. The sodium halide that is washed out of the interstices of the composite by water leaching is therefore present in the greatest quantity in the first part of the effluent and in decreasing amounts in the subsequent parts of the lithium halide solution. A lithium halide solution is thus obtained which contains only a significant amount of sodium halide as an impurity. The "resin/aluminate composite" used in the present invention is preferably made by incorporating crystalline LiX.2Al(OH) ₃ (where X is a halide) into an ion exchange resin, as shown in the above-mentioned literature. manufactured by
Pending U.S. Patent Application No. 1, filed November 19, 1979
095691 (U.S. Pat. No. 4,381,349). "Halide" used in the expression "Na halide" or "LiX" herein means Cl, Br, or I, with Cl being preferred. For the sake of simplicity of this disclosure, halides will be shown as preferred chlorides, with the understanding that bromides or iodides are also suitable. The substantially pure alkali metal solution used in the present invention refers to a solution (brine) of an alkali metal halide other than lithium halide, and will be explained below using sodium halide brine (abbreviated as NaCl brine) as an example. It goes without saying that a small amount of Li ⁺ may be mixed in these NaCl brines. This relatively pure but highly concentrated frame is used to pre-clean the lithium-loaded resin/aluminate composite prior to the water leaching step.
NaCl brine; the water leaching step removes most of the Li ⁺ (but not all of the Li ⁺ ) from the complex.
is carried out to remove the conjugate and thus render the complex substantially "unloaded." The concentrated NaCl brine is preferably at or near saturation, but any concentration above about 20 percent will provide a significant degree of operating efficiency. Furthermore, as the concentration decreases, the effect of the operation becomes less and less. From a practical standpoint to achieve economical and effective operation, the concentration is preferably between 24 percent and 26 percent. Li ⁺ -containing aqueous solutions or brine solutions that are subjected to adsorption treatment on resin/aluminate composites are contaminated with Li ⁺ or metal ions other than alkali metal ions. These other metal ions are usually Mg ⁺⁺ ,
Alkaline earth metal ions such as Ca ⁺⁺ , etc.
It can also be essentially any cation other than an alkali metal. Li ⁺ -supported resin/aluminate composites with contaminant metal cations other than alkali metal cations in their interstices absorb or pick up Li ⁺ ions from the impure brine, leaving the complex in a substantially “unsupported” state. It is usually derived from a process in which it is used to carry Li ⁺ ions. Of course, any Li ⁺ -supported resin/aluminate composite with any "other" metal cation interspersed therewith can be used in this process. The purpose and intent of the process is to remove contaminating metal cations from the interstices without removing significant amounts of Li ⁺ ions: this operation is performed with a relatively pure, preferably concentrated NaCl prewash. The goal is to leave the Li ⁺ ions in place and fill the gap with a relatively pure NaCl brine free of the contaminating metal cations. When water leaching is subsequently used for the separation of Li ⁺ from the complex, most of the NaCl and some of the Li ⁺ are washed out in the first part of the effluent. The subsequent part is essentially pure Li ⁺ containing only a trace amount of NaCl.
It is a solution. This Li ⁺ is derived from raw materials and is usually obtained in the form of LiX. It is preferable not to remove all Li ⁺ from crystalline LiX.2Al(OH) ₃ because removing all Li ⁺ may lead to collapse or destruction of the crystalline aluminate structure. Therefore, it is best that the water used for water leaching contains a small amount (about 80 ppm or more) of Li ⁺ to prevent removal of all Li ⁺ from the aluminate structure. It is believed that the higher the concentration of NaCl, the greater the tendency of the crystalline aluminate structure to adsorb and retain Li ⁺ . In the process of water leaching, the NaCl concentration in the interstices of the complex decreases a little, and as this decrease occurs, Li ⁺ becomes more and more easily leached from the crystals. One way to thereby remove Li ⁺ from aqueous solutions is to form a precipitate as lithium carbonate (Li ₂ CO ₃ ). If other metal cations, such as alkaline earth metal cations, are present, they precipitate together with lithium as carbonates. Sodium carbonate does not precipitate with lithium carbonate, so Li ⁺
NaCl in solution does not pose the same contamination problems as other metal cations. Furthermore, if NaCl is the only contaminant in the Li ⁺ solution, it is possible to crystallize NaCl by evaporating most of the water, leaving a pure frame highly concentrated LiCl solution: alkaline earth This operation is not possible with similar metals. The water used for water leaching of Li ⁺ from the aluminate structure of the composite is virtually devoid of other metal cations (such as alkaline earth metal cations) except for the small amount of Li ⁺ that should be present. It should be something. Small amounts of alkali metal cations, such as Na ⁺ , may also be tolerated. Deionized (softened) water may be used as well as distilled water or other sufficiently pure water.
Both are provided that substantially no alkaline earth metal or non-alkali metal cations are present. The following examples are presented to illustrate certain embodiments, and the invention is not limited to the particular embodiments described therein. In the examples below, the water leaching step is approximately 68 ppm.
carried out using deionized water containing Li ⁺ ions,
The crude (impure) Li ⁺ -containing feed brine from which Li ⁺ ions are to be extracted is substantially saturated with NaCl and contains only about 280 ppm Li ⁺ ions, about 6.8 percent Na ⁺ , about 17.05 percent Cl ^- , about 0.41% K ⁺ , ca. 0.31% Mg ⁺⁺ , ca. 3.3% Ca ⁺⁺ , ca. 0.23% Sr ⁺⁺ , ca.
0.022% B ⁺⁺⁺ , about 20-30ppm Mn ⁺⁺ ,
Minerals from the Smackover deposit near Magnolia, Arkansas, containing about 20-30 ppm Mo ⁺⁺ and about 9-10 ppm Cu ⁺⁺ , with a pH of about 5.8. It's brine. The essentially pure NaCl brine used for pre-cleaning prior to water leaching was saturated and contained approximately 200 ppm Li ⁺ ions and had a pH of 6.3. The resin/aluminate composites used in all examples (and comparative examples) were crystalline to weakly basic anion exchange resins commercially available from The Dow Chemical Company under the trade name DOWEX MWA-1. A material containing LiCl.2Al(OH) ₃ was used. The vessel used was a 120 c.c. capacity glass ion exchange column with a jacket for circulating fluid for temperature control. Example 1 An ion exchange column was packed with a resin/aluminate composite that had been previously subjected to water leaching, rendering the composite substantially "unsupported" in terms of Li ⁺ content. The total hardness (Mg ⁺⁺ , Ca The crude brine was passed through the composite bed until the values were the same (e.g. ⁺⁺ ). A prewash of relatively pure saturated NaCl brine was then carried out to replace the crude brine remaining in the interstices of the composite; the prewash was carried out until the hardness of the effluent was less than 0.002M. , passed through the column at a rate of 3.3 cc/min. Next, the water flow rate is 3.3
The water leaching step was carried out at cc/min. The effluent from the column has density, molar hardness and
Each cut was separated for analysis of ppmLi ⁺ . The table displays the elution pattern for one cycle of supported brine wash/leach. Those skilled in the art will readily understand that the "unsupported" conjugate can be subjected to multiple such cycles.

Table: The peak cuts (19-24) had very low hardness values, if any at all. Comparative Example This example illustrates the effect of omitting the NaCl prewash of the present invention. Li-enriched LiCl.2Al(OH) ₃ crystalline material prepared substantially by the process described in U.S. Pat. No. 4,381,349, where the exchange column bed had a volume of 170 c.c. The temperature of the column using the contained resin composite was 90°C. The procedure of Example 1 was substantially followed except that the flow rate was 2.5% per column bed per minute and the wash water (for leaching) contained about 60 ppm Li ⁺ . After passing sufficient smackover brine through the resin/aluminate composite, the water leaching step was carried out without prewashing with NaCl solution. As can be seen from the following table, the "peak" cut of Li ⁺ concentration had a significant degree of hardness value.

[Table] Example 2 This example was carried out substantially in the same manner as Example 1. Until the effluent reaches the same Li ⁺ concentration as the raw material.
Smackover brine was pumped down a 120 c.c. bed containing lithium chloroaluminate dispersed in DOWEX MWA-1 resin:
Li ⁺ concentration was measured by standard atomic absorption spectrometry. A prewash of pure saturated NaCl brine was passed through the bed at a rate of 2.75% per bed volume per minute. After prewashing approximately 0.83 bed volumes, the bed was flushed with deionized water containing 280 ppm Li ⁺ for 1.66 bed volumes and the effluent was collected cut by cut. The flow of smackover brine was then resumed at a flow rate of 8.2% bed volume per minute to recharge or "reload" the resin composite with lithium. Elution data is shown in the table.

[Table] Start

[Table] Among the cuts in the table, 18−21 is approximately 3912ppmLi ⁺
It had a low hardness and was collected as a product cut. The remaining cut was used as follows, with the majority being used in the concentration cycle. The data is shown in the table. Cuts 1-6 were recycled to the raw material tank, cuts 7, 8 and 9 were combined to “carry” Li ⁺ in the resin.
The resin/aluminate bed was flushed to allow for the solution. Cuts 10-13 were combined and passed through the resin bed. Cuts 14-15 were combined and passed through the resin bed. 33c.c. to replace the portion of cut 7-15 that was already missing or taken at the time of sample collection.
Passed the new meir asp brine. Cuts 16 and 17 were combined and passed through the bed saturated with NaCl. I kept Katsuto 18-21 as a product. Katsuto 22-23 was combined and passed through the floor.
Make-up amount of deionized water of 280ppmLi ⁺ (34
cc) passed through the floor. The data are shown in the table.

【table】

[Table] Example 3 In this experiment, a suitable cut is selected from the cuts shown in the table, and further enrichment of Li ^{+ is demonstrated by carrying out multi-stage adsorption and desorption of Li + .} Therefore,
This preferred method of operation consists of utilizing a portion of the effluent of the sequential run. This was accomplished by storing the effluent in coils or in a series of tanks. The “new” material required for each elution cycle is therefore a make-up of fresh deionized water (containing a small amount of Li ⁺ ) equal in volume to the product cut.
It was just the amount of boost, and also the “reflux”
It was only necessary to have enough NaCl to resaturate a portion of the cut to be reused for a pre-wash called . In multi-stage operations using Li-containing cuts from previous runs, the product concentration increased over that obtained in a single cycle. Looking at the cuts in the table, the first six cuts had relatively high hardness and low Li content, so they were recycled to the smackover brine raw material. cutlet 7, 8
and 9 were combined to form the first solution and pumped onto the column for equal volume smack-over brine elution. Merged Katsuto 10, 11 and 12,
Pumped after the 7, 8, and 9 mixtures. 13,
This was followed up with a solution prepared by mixing 14, 15, and 16 (Kutto 10, 11, and 12 mixture);
17, 18, and 19 were then resaturated with NaCl and pumped onto the column. Cutlets 20, 21, 22, and 23 were reserved as products. Cuts 24-30 were merged and made to follow the "reflux" mixture of 17, 18, and 19. Then (of equal volume to the product cut)
The 24-30 cut mixture was followed with deionized water containing 280 ppmL Li ⁺ . All effluent from this run was collected in separate cuts as before for use in the next concentration cycle. This method was repeated until the fifth cycle. The product cuts increased in concentration from 3912 ppmLi ⁺ (1st cycle) to 5531 ppmLi ⁺ (5th cycle) with little or no increase in total hardness.

Claims (1)

[Claims] 1. A method for leaching Li ⁺ from a porous resin/aluminate composite containing a brine contaminated with metal ions other than alkali metal ions, wherein the resin/aluminate composite contains crystalline LiX・2Al
(OH) ₃ (where X represents a halide) dispersed therein and carrying Li ⁺ , the process produces a composite that is at least 20% pure and free of the contaminants. Prewashing with an alkali metal halide solution at a concentration of 100 ml to wash contaminated brine from the complex without removing much Li ⁺ and water leaching to remove Li ⁺ with a pure alkali metal halide solution from the complex. A method for obtaining a high purity Li ⁺ solution from a resin/aluminate composite, characterized in that the amount of Li + leached from the resin leaves a composite in which the amount of Li ⁺ is reduced but not completely eliminated. 2. The method according to claim 1, wherein X is chloride. 3. The method according to claim 1 or 2, wherein the alkali metal halide solution is a saturated sodium chloride solution. 4. The method of claim 3, wherein the concentration of the sodium chloride solution is within the range of 20% to 26%. 5. The method according to any one of claims 1, 2, 3, and 4, wherein the water used for water leaching contains 80 ppm or more of Li ⁺ . 6. The method according to any one of claims 1, 2, 3, 4 and 5, wherein the concentrated alkali metal halide solution used for pre-cleaning contains a small amount of lithium halide. 7. A process according to claim 6, wherein the lithium halide is obtained from at least one previous cycle pre-cleaning step and/or water leaching step. 8. The method of claim 6, wherein the alkali metal halide solution containing a small amount of Li halide is prepared by adding NaCl to at least a portion of the eluent from the water leaching step of the previous cycle. 9. A method according to any one of claims 1 to 6, in which the Li ⁺ -unloaded composite is reloaded with Li ⁺ with a Li ⁺ -containing contaminated brine.