EnergySource Minerals, LLC v. TerraLithium LLC

1. Case Identification

• Case #: IPR2019-01XXX
• Patent #: 9,051,827
• Filed: September 11, 2019
• Petitioner(s): EnergySource Minerals, LLC
• Patent Owner(s): All American Lithium LLC
• Challenged Claims: 9-16

2. Patent Overview

• Title: Selective Removal of Silica From Silica Containing Brines
• Brief Description: The ’827 patent discloses a method for preventing silica scale in geothermal brine reinjection wells. The method involves selectively removing silica from geothermal brine by oxidizing naturally present iron (II) salt to iron (III) hydroxide, adjusting the brine's pH to between 4.5 and 6, contacting the silica with the iron (III) hydroxide to form a precipitate, and separating the precipitate to produce a liquid fraction with reduced silica and iron concentrations for reinjection.

3. Grounds for Unpatentability

Ground 1: Claims 9-16 are anticipated by and/or obvious over Jost

• Prior Art Relied Upon: Jost (Patent 4,405,463).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Jost teaches a nearly identical process for stabilizing silica-rich geothermal brine from the same Imperial Valley region to prevent scaling. Jost allegedly disclosed every step of independent claim 9, including: obtaining brine containing silica and ferrous ions (iron (II) salt); oxidizing the ferrous ions to ferric ions to form ferric hydroxide (iron (III) hydroxide); adjusting the brine's pH to a range (3-5) that overlaps the claimed range (4.5-6.5); contacting the silica and ferric hydroxide to form a precipitate; separating the precipitate from the liquid fraction; and reinjecting a clarified brine with a reduced silica content ("below 150 ppm," which Petitioner contended meets the "less than about 80 ppm" limitation). Petitioner further argued that the dependent claims' concentration limits are inherently disclosed or rendered obvious by Jost’s teachings.
  • Key Aspects: Petitioner contended that any differences between claim 9 and Jost are mere changes in terminology for the same well-known chemical processes and that Jost's disclosure of a process for "substantially silica scale-free brine reinjection" anticipates the patent's purpose and method.

Ground 2: Claims 9-16 are anticipated by and/or obvious over Maimoni

• Prior Art Relied Upon: Maimoni (A Cementation Process for Minerals Recovery from Salton Sea Geothermal Brines, 1982).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Maimoni, which describes the Hazen pilot plant process for treating Salton Sea brines, anticipates or renders obvious all challenged claims. The Hazen process involved obtaining geothermal brine with silica and iron (II); oxidizing the iron to a ferric state by sparging air; maintaining the pH within the claimed range (5.2-6.1); co-precipitating silica and iron; separating the solids; and reinjecting the brine. Maimoni explicitly shows the post-treatment liquid fraction has a silica concentration of 22 ppm and an iron concentration of 13 ppm, satisfying the limitations of claims 9, 10, 11, 13, and 14. Furthermore, Maimoni discloses a lithium recovery unit, anticipating claim 15.
  • Key Aspects: Petitioner highlighted that Maimoni provides specific, measured concentration values from a real-world pilot plant that fall squarely within the ranges of the challenged claims, demonstrating the claimed process was known and practiced decades prior.

Ground 3: Claims 9-16 are obvious over Jost in view of Maimoni

• Prior Art Relied Upon: Jost (Patent 4,405,463) and Maimoni (A Cementation Process for Minerals Recovery from Salton Sea Geothermal Brines, 1982).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Jost teaches the fundamental method of claim 9. To the extent Jost does not explicitly disclose the specific, narrow concentration ranges recited in dependent claims 10-14, Maimoni provides this missing information. Maimoni's detailed data from the Hazen pilot plant demonstrates that achieving silica levels below 35, 20, and 10 ppm, and iron levels below 15 ppm, was a known result of applying these silica removal techniques to Salton Sea brine.
  • Motivation to Combine: A POSITA would combine these references because both are directed to the same problem: mineral recovery and silica removal from geothermal brines in the same geographical area (Imperial Valley). A POSITA would look to a detailed pilot plant study like Maimoni to find specific operating parameters and expected results to optimize the general process described in Jost.
  • Expectation of Success: The combination would have a high expectation of success as it involves applying specific, successful process parameters from Maimoni to the analogous process in Jost, both of which operate on the same type of brine.

• Additional Grounds: Petitioner asserted additional challenges against claims 9-16, including anticipation and/or obviousness over Wilkins (Patent 4,016,075) alone, and obviousness over Wilkins in view of Maimoni, relying on similar arguments that the prior art teaches all steps of the claimed method.

4. Key Claim Construction Positions

• Petitioner argued for specific constructions of three key terms to align the patent's language with that used in the prior art.
  • "geothermal brine solution": Proposed a broad construction to mean any aqueous brine from a geothermal well, establishing that the brines in the prior art (e.g., from the Salton Sea) are the same as those claimed.
  • "iron (II) salt": Proposed this term be construed to include its naturally disassociated constituent components, such as ferrous ions (Fe²⁺). This was critical because the prior art frequently refers to "ferrous ions" rather than "iron (II) salt."
  • "iron (III) hydroxide": Proposed this term be construed to encompass related species like ferric oxyhydroxide and ferric ions (Fe³⁺). This construction was essential to map prior art disclosures of oxidizing ferrous ions to ferric ions and forming precipitates onto the claimed steps.

5. Key Technical Contentions (Beyond Claim Construction)

• A central contention was that many limitations in the challenged claims, particularly the specific concentration and pH ranges in the dependent claims, are not novel inventive features but are merely arbitrary recitations of inherent characteristics of a known process. Petitioner argued that because the process inputs (Salton Sea brine) are naturally occurring and the core process steps were well-known, patentability must depend on the novelty of the steps themselves, not on the arbitrary selection of outcome-based concentration values that were already achievable using prior art methods.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 9-16 of Patent 9,051,827 as unpatentable.