Chemistry of inorganic compounds – Treating mixture to obtain metal containing compound – Alkali metal
Reexamination Certificate
1996-09-20
2001-08-28
Bos, Steven (Department: 1754)
Chemistry of inorganic compounds
Treating mixture to obtain metal containing compound
Alkali metal
C423S181000, C502S415000, C252S184000
Reexamination Certificate
active
06280693
ABSTRACT:
FIELD OF THE INVENTION
Lithium values are recovered from lithium-containing brines as a lithium salt using altered polycrystalline hydrated alumina.
BACKGROUND OF THE INVENTION
Previous methods of extracting lithium values from brines which contain lithium are disclosed in the following U.S. Pat. Nos.: 4,116,856; 4,116,858; 4,159,311; 4,221,767; 4,291,001; 4,347,327; 4,348,295; 4,348,296; 4,348,297; 4,376,100; 4,381,349; 4,430,311; 4,461,714; 4,472,362; and 4,477,367. These patents pertain, in various ways, to creating lithium aluminates within the interstices or pores of ion exchange resins, or on other substrates, porous and non-porous. Microcrystalline lithium aluminates formed within ion exchange resins are useful in selectively removing lithium values from Li-containing brines.
Over the years, it has been found that ion exchange resin compositions were often fouled by substances in the brine, such as hydrocarbon contaminants, that rendered the ion exchange resin incapable of rejuvenation requiring re-manufacture of resin.
In
Lithium—Current Applications in Science, Medicine and Technology
, R. O. Bach Editor, published by John Wiley and Sons, 1985, there is an article on pp. 29-34, authored by W. C. Bauman, J. L. Burba, III and J. M. Lee, titled “Structure And Operation Of Dow's New Lithium-Selective Ion-Exchange Resin” containing some background information of relevance to the subject matter of this present disclosure.
We have now, unexpectedly, found it preferable to infuse LiOH into the polycrystalline hydrated alumina pellets, herein referred to as Al(OH)
3
, by reacting it, in the presence of water, with LiOH in the absence of NaCl or other salt. We find that infusion of LiOH into Al(OH)
3
pellets proceeds with maintenance of pellet integrity up to and beyond 0.2 mol fraction, and up to 0.33 mol fraction of LiOH in the so-formed LiOH/Al(OH)
3
. Furthermore, we find that having initially prepared the intercalation in the absence of NaCl or other salt, the pellets can then be converted to the LiCl form with aqueous HCl and used for the specific recovery of LiCl from brine without pellet breakage. Our prior work with intercalating LiCl directly into the crystals to form LiCl/Al(OH)
3
was limited to amounts of up to about 0.2 mol fraction of LiCl in order to avoid breaking up the pellets. Also, we have now determined that these so-altered polycrystalline alumina pellets containing more than 0.2 mol fraction, up to 0.33 mol fraction, of LiCl in the LiCl/Al(OH)
3
produced in the presently described method, offer significant improvements in costs and efficiency for recovering LiCl from brine compared to the material identified hereinabove as being of relevance in “Structure And Operation of Dow's New Lithium-Selective Ion-Exchange Resin.”
SUMMARY OF THE INVENTION
This invention comprises an altered polycrystalline hydrated alumina composition, its preparation, and its use for selectively recovering lithium values from brines which contain lithium ions.
The composition comprises pellets, each of said pellets consisting essentially of an integral mass of polycrystalline hydrated alumina pellets morphologically altered by the infusion therein of LiOH (lithium hydroxide) which creates active lithium-specific sites within the crystal layers of the alumina, essentially without. decrepitation of the layered structure. The composition is prepared by adding an aqueous LiOH solution to a polycrystalline hydrated alumina (especially Gibbsite) in an amount to provide up to 0.33 mol fraction of LiOH in the polycrystalline LiOH/Al(OH)
3
.
The so-prepared infused alumina pellets are used in the process of removing lithium values from brine by contacting it with a solution of LiX (where X is nitrate, sulfate, bicarbonate, halide, or other acid salt moiety, especially chlorine) to convert the LiOH to LiX. The resulting LiX/Al(OH)
3
, having a mol fraction of LiX of up to 0.33, especially from above about 0.2 and up to 0.33, is a beneficial improvement in comparison with the previously attained loadings of up to about 0.2 mol fraction of LiX disclosed in our above-identified related application.
DETAILED DESCRIPTIONS INCLUDING BEST MODE CONTEMPLATED
In this disclosure the LiX of greatest interest is LiCl, and the brines of greatest interest, besides seawater, are subterranean brines, such as that from the Smackover formation which runs largely through Arkansas and into Texas.
In preparing the unique compositions of this invention, there is selected a polycrystalline hydrated alumina of pellet size which is suitable for use in a column without encountering excessive packing and blinding which interferes with efficient flow of liquids through a bed of the pellets. We find it preferable to use polycrystalline pellets of hydrated alumina known as crystalline Gibbsite, such as that which is commercially available as LaRoche H-30TM, Reynolds Metal RH-30TM, and Alcoa C-30TM. Other polycrystalline pellets can be used, such as those made from Bayerite, Norstrandite or Bauxite.
The process known as the Bayer process is used to manufacture polycrystalline hydrated alumina from various alumina-containing ores or minerals (usually bauxite) to make a coarse product which is suitable for use in this invention. Preferably the particle size of the pellets is not smaller than about 140 mesh, U.S. standard sieve size, and can be as large as about 10 mesh U.S. standard sieve size.
In general, the altered polycrystalline pellets are prepared by adding an aqueous LiOH solution to a polycrystalline hydrated alumina, herein Al(OH)
3
, esp. Gibbsite, in an amount to provide LiOH/Al(OH)
3
containing, preferably, from about 0.2, up to maximum of 0.33 mol fraction of LiOH as an intercalant. This is readily done in a vessel at an ambient temperature in the range of 0° C. to 25° C. for 24 to 48 hours while adding enough pure water to keep the pellets submerged.
Preparation of pellets for use in the recovery of LiCl from brine consists in the neutralization of the LiOH/Al(OH)
3
pellets with dilute HCl in excess H
2
O, preferably in the presence of NaHCO
3
as a buffer at pH of about 5 to 6. This neutralization step can be done at ambient temperature, and does not normally require more than a few minutes of good mixing, depending on the size of the mixing vessel. The buffer is to assure that the acidity does not become excessive.
We have determined that the present invention offers improvements in costs and efficiency for recovering lithium values from brines. The polycrystalline alumina pellets of the present invention are so inexpensive, compared with ion exchange resins, that it is more cost effective to discard spent alumina or convert it to other uses than to repeatedly rejuvenate it as an infused alumina. Also, the preparation of the lithium-capturing pellets of the present invention is relatively simple and easily managed in-situ in a vessel in which it is to be used, though it can be prepared in one vessel and then transferred to another vessel for use. A more concentrated and more pure LiX (where X is a halide ion, usually chloride) product can be obtained from the Li-containing brine, as compared to the known use of ion exchange resins.
Furthermore the present invention distinguishes over the related invention of our above cross-referenced application by not requiring an initial loading of LiX into the hydrated alumina compound in which pellet breakage was found to be encountered at loadings exceeding 0.2 mol per mol of Al(OH)
3
.
Once the hydrated alumina has been infused with an initial amount of LiOH and neutralized with an acid to provide active LiX sites of up to 0.33 mol fraction, the LiX is washed out with water to remove much of the “loadings” of the active sites and the “unloaded” sites are efficiently used to take up more LiX from brine, and used again a plurality of times before becoming exhausted.
REFERENCES:
patent: 4116856 (1978-09-01), Lee et al.
patent: 4116858 (1978-09-01), Lee et al.
patent: 4159311 (1979-06-01), Lee et al.
patent: 4221767 (1980-09-01), Lee et al.
patent: 4291
Bauman William C.
Burba, III John L.
Alston & Bird LLP
Bos Steven
FMC Corporation
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