US-12623911-B2 - Methods for removing potassium, rubidium, and cesium, selectively or in combination, from brines and resulting compositions thereof

Abstract

The invention generally relates to methods of removing potassium, rubidium, and/or cesium, selectively or in combination, from brines using tetrafluoroborates. Also disclosed are methods of producing potassium, rubidium, and/or cesium chlorides using ionic liquids and exchange media. This invention also generally relates to treated geothermal brine compositions containing reduced concentrations of silica, iron, and potassium compared to the untreated brines. Exemplary compositions of the treated brine contain a concentration of silica ranging from about 0 mg/kg to about 15 mg/kg, a concentration of iron ranging from about 0 mg/kg to about 10 mg/kg, and a concentration of potassium ranging from about 300 mg/kg to about 8500 mg/kg. Other exemplary compositions of the treated brines also contain reduced concentrations of elements like rubidium, cesium, and lithium.

Inventors

• Stephen Harrison
• C.V. Krishnamohan Sharma
• Raghunandan Bhakta
• Pei-Yu Lan

Assignees

• TERRALITHIUM LLC

Dates

Publication Date

20260512

Application Date

20230316

Claims (5)

1. 1 . A method for preparing potassium chloride, rubidium chloride and/or cesium chloride from a tetrafluoroborate solution containing potassium tetrafluoroborate, rubidium tetrafluoroborate, and/or cesium tetrafluoroborate, the method comprising the steps of: contacting the tetrafluoroborate solution containing potassium tetrafluoroborate, rubidium tetrafluoroborate, and/or cesium tetrafluoroborate with an aqueous solution containing an ion-exchange media containing chloride to produce a tetrafluoroborate/ion-exchange media mixture; heating the tetrafluoroborate/ion-exchange media mixture to produce an ion-exchange media layer and an aqueous layer containing potassium chloride, rubidium chloride and/or cesium chloride; separating the aqueous layer containing potassium chloride, rubidium chloride and/or cesium chloride from the ion-exchange media layer; and evaporating the aqueous layer to produce solid potassium chloride, rubidium chloride, and/or cesium chloride.
2. 2 . The method of claim 1 , wherein the tetrafluoroborate solution comprises potassium.
3. 3 . The method of claim 2 , wherein the potassium tetrafluoroborate is added to the ion-exchange media mixture in an amount between about 0.5 to 10 grams of potassium tetrafluoroborate for every 100 grams of ion-exchange media mixture.
4. 4 . The method of claim 1 , where in the ion-exchange media is quaternary ammonium functional-terminated chloride terminated resin beads.
5. 5 . The method of claim 1 , wherein the tetrafluoroborate/ion-exchange media mixture is heated to a temperature of between about 70-100° C.

Description

RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 14/188,293, filed on Feb. 24, 2014, which claims priority to U.S. Provisional Patent Application Ser. No. 61/873,212, filed on Sep. 3, 2013, and is a Continuation-in-Part of U.S. patent application Ser. No. 12/822,580, filed on Jun. 24, 2010, now U.S. Pat. No. 8,597,521, issued on Dec. 3, 2013, which claims priority to U.S. Provisional Patent Application 61/220,000, filed on Jun. 24, 2009; U.S. application Ser. No. 14/188,293, filed on Feb. 24, 2014 claims priority to U.S. Provisional Patent Application Ser. No. 61/780,308, filed on Mar. 13, 2013, and U.S. Provisional Patent Application Ser. No. 61/873,212, filed on Sep. 3, 2013; also claims priority to, and is a Continuation-in-Part of U.S. patent application Ser. No. 14/062,781, filed on Oct. 24, 2013, which is a Continuation Application of U.S. application Ser. No. 12/822,580, filed Jun. 24, 2010, now U.S. Pat. No. 8,597,521, issued Dec. 3, 2013, which claims priority to U.S. Provisional Patent Application Ser. No. 61/220,000, filed on Jun. 24, 2009; U.S. application Ser. No. 14/188,293, filed on Feb. 24, 2014, also claims priority to and is a Continuation-in-Part of U.S. patent application Ser. No. 12/823,000, filed on Jun. 24, 2010, now U.S. Pat. No. 9,051,827, issued Jun. 9, 2015, which claims priority to U.S. Provisional Patent Application Ser. No. 61/239,275, filed on Sep. 2, 2009, all of which are incorporated herein by reference in their entireties. TECHNICAL FIELD OF THE INVENTION The invention generally relates to methods of removing silica and iron from brines, as well as removing potassium, rubidium, and/or cesium, selectively or in combination, from brines using tetrafluoroborates, as well as the treated brine compositions that result therefrom. Additionally, the invention relates to methods of producing potassium chloride, rubidium chloride, and/or cesium chlorides using ionic liquids and ion exchange media, and treated brine compositions that result therefrom. BACKGROUND A number of brine sources exist naturally. For instance, brine sources include brine deposits like the Salar de Atacama in Chile, Silver Peak Nevada, Salar de Uyuni in Bolivia, or the Salar de Hombre Muerte in Argentina. Other common brine sources are geothermal, oilfield, Smackover, and relict hydrothermal brines. These brines, however, have not previously been commercially exploited very well. Geothermal brines are of particular interest for a variety of reasons. First, geothermal brines provide a source of 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-steam can be used, for example, to run a power plant. Additionally, geothermal brines contain useful elements, which can be recovered and utilized for secondary processes. In some geothermal waters and brines, binary processes can be used to heat a second fluid to provide steam for the generation of electricity without the flashing of the geothermal brine. One problem associated with geothermal brines when utilized for the production of electricity results from scaling and deposition of solids. Silica and other solids that are dissolved within the geothermal brine precipitate out during all stages of brine processing, particularly during the cooling of a geothermal brine, and may eventually result in fouling of the injection wells or processing equipment. It is known that geothermal brines can include various metal ions, particularly alkali and alkaline earth metals, as well as silica, iron, lead, silver, and zinc, in varying concentrations, depending upon the source of the brine. Recovery of these metals is potentially important to the chemical, pharmaceutical, and electronic industries. Typically, the economical 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. Economical recovery also depends upon the commercial cost and availability of the desired metal already present in the relevant market. Some of the desired metals that can be present in brines are potassium, rubidium, and cesium. Economically recoverable deposits of potassium are rare. The potassium concentration in the Salton Sea geothermal brine, however, is around 24,000 parts per million. Potassium that has been extracted from brines can easily be converted into potassium chloride, which is useful in a variety of applications including agriculture, medicine, food processing, and as a standard measure of conductivity of ionic solutions in the chemical arts. Currently, there are no existing potassium, rubidium, and cesium remo