Sorbent for Lithium Extraction

Abstract

This invention relates to a method for preparing a lithium aluminate intercalate (LAI) matrix solid and methods for the selective extraction and recovery of lithium from lithium containing solutions, including brines. The method for preparing the LAI matrix solid includes reacting aluminum hydroxide and a lithium salt for form the lithium aluminate intercalate, which can then be mixed with up to about 20% by weight of a polymer to form the LAI matrix.

Description

Related applications

This application claims priority to U.S. Provisional patent application ser. No. 61/261,114, filed on Nov. 13, 2009, which is incorporated herein by reference in its entirety.

Background of the invention

1. Technical field of the invention

The invention generally relates to the field of selectively removing and recovering lithium from solution. More particularly, the invention relates to methods and materials for the selective removal and recovery of lithium ions from a lithium ion containing brine, preferably without the substantial removal of other ions from the brine.

2. Description of the prior art

Approximately 75 to 80% of lithium chloride and lithium carbonate, and their derivatives, are currently produced from the recovery of lithium from brines, via natural evaporative processes. The invention described herein is applicable to these and other brine sources.

Geothermal brines are of particular interest for a variety of reasons. First, some geothermal brine provide a source of electrical power due to the fact that hot geothermal pools are stored at high pressure underground, which when released to atmospheric pressure, can provide a flash-steam. The flash-stream can be used, for example, to run a power plant. In some geothermal waters and brines, associated binary processes can be used to heat a second fluid, which can provide steam for the generation of electricity without the flashing of the geothermal brine. Additionally, geothermal brines contain various useful elements, which can be recovered and utilized for secondary processes.

It is known that geothermal brines can include various metal ions, particularly alkali and alkaline earth metals, as well as transition metals such as lead, silver and zinc, in varying concentrations, depending upon the source of the brine. Recovery of these metals is potentially important to the chemical and pharmaceutical industries. Typically, the economic recovery of metals from natural brines, which may vary widely in composition, depends not only on the specific concentration of the desired metal, but also upon the concentrations of interfering ions, particularly silica, calcium and magnesium, because the presence of the interfering ions will increase recovery costs as additional steps must be taken to remove the interfering ions.

As lithium has gained importance as an element for use in various applications, such as for use in batteries, research has been conducted to develop simple and inexpensive methods for the recovery thereof. For example, Burba previously developed two- and three-layer lithium aluminates for the recovery of lithium from brines. (see, for example, U.S. Pat. Nos. 4,348,295 and 4,461,714). The prior art methods that employ packed columns for the recovery, however, suffer from many drawbacks, such as shortened lifetimes due to the slow deterioration and disintegration of the particles.

Thus, there exists the need for the development of improved methods for the selective recovery of lithium from lithium containing brines that are easy to use, have a high capacity for the recovery of lithium, and have a long service life.

Summary of the invention

Methods for the selective removal of lithium from lithium containing solutions, such as brines, geothermal brines, salar (salt flat) brines, continental brines, including smackover brines, oilfield brines, and high ionic strength solutions are provided herein. Also provided are methods for preparing sorbent compositions for the recovery of lithium from lithium containing solutions.

In one aspect, a method for preparing a composition for the recovery of lithium from a brine is provided. The method includes the steps of preparing a lithium aluminate intercalate solid by contacting a lithium salt with alumina under conditions sufficient to infuse the alumina with lithium salt, wherein the mole ratio of lithium to alumina is up to about 0.5:1; and mixing the lithium aluminate intercalate solid with a polymer material to form a matrix. The lithium aluminate intercalate solid is present in an amount of at least 80% by weight and the polymer is present in an amount of between about 1% and 20% by weight. In certain embodiments, the lithium salt is lithium chloride. In other embodiments, the lithium salt can be selected from the group consisting of lithium chloride, lithium bromide, lithium nitrate, or lithium hydroxide. In certain embodiments, the polymer is a solid or a powder. In certain embodiments, the alumina is selected from gibbsite, alumina hydrate, bayerite, nordstandite, bauxite, amorphous aluminum trihydroxide and activated alumina.

In another aspect, a composition for the recovery of lithium from a brine is provided. The composition includes particulate material that includes a lithium aluminate intercalate and a polymer. The lithium aluminate intercalate is produced by infusing alumina with a lithium salt to produce a lix/al(oh)3 solid having a mole fraction of lithium to aluminum of up to 0.33, wherein x is the anion of the lithium salt. The lithium aluminate intercalate is present in an amount of at least about 80% by weight and the polymer is present in an amount of between about 1% and 20% by weight. In certain embodiments, the lithium salt is lithium chloride. In certain embodiments, the polymer is selected from the group consisting of polyethylene, ultra high molecular weight polyethylene, high density polyethylene, polypropylene, poly vinyl alcohol, poly acrylic acid, polyvinylidinedifluoride, polytetrafluoroethylene, and epoxy thermosets. In certain embodiments, the polymer comprises an emulsified water insoluble polymer. In certain embodiments, the water insoluble polymer comprises a fluoropolymer.

In another aspect, a method for the removal and recovery of lithium from geothermal brines is provided wherein the method includes the steps of: providing an extraction and recovery apparatus comprising a lithium aluminate intercalate matrix, wherein the matrix is prepared by the steps of contacting a lithium salt with alumina and hydrochloric acid under conditions sufficient to infuse the alumina with the lithium salt, wherein the mole ratio of lithium to alumina is up to about 0.5:1; and mixing the lithium aluminate intercalate solid with a polymer material to form a matrix, wherein said lithium aluminate intercalate solid is present in an amount of at least about 80% by weight and said polymer is present in an amount of between about 1% and 20% by weight. The method further includes the step of washing the matrix with at least 1 bed volume of a wash solution comprising at least about 50 ppm lithium and supplying a geothermal brine to the extraction and recovery apparatus and contacting said geothermal brine with the lithium aluminate intercalate matrix, wherein the contacting step is sufficient to extract lithium chloride from the geothermal brine. The method further includes monitoring the output of the extraction and recovery apparatus to determine the saturation of the lithium aluminate intercalate matrix; and recovering extracted lithium chloride by washing the lithium aluminate intercalate matrix with the wash solution. In certain embodiments, the lithium salt is lithium chloride.