EnergySource Minerals LLC v. TErrALithium LLC

1. Case Identification

• Case #: IPR2019-01601
• Patent #: 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 selectively removing silica from geothermal brines to prevent scaling in reinjection wells. The method involves oxidizing iron (II) salt present in the brine to iron (III) hydroxide, maintaining a specific pH, and using the iron (III) hydroxide to precipitate the silica for removal.

3. Grounds for Unpatentability

Ground 1: Claims 9-16 are anticipated 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, which teaches a process for stabilizing silica-rich geothermal brine, discloses every element of independent claim 9. Jost describes obtaining brine with indigenous ferrous ions (iron (II) salt), oxidizing them to form ferric ions and subsequently ferric hydroxide, and maintaining a brine pH that overlaps the claimed range of 4.5-6.5. Jost further teaches contacting the silica with the ferric hydroxide to form an insoluble precipitate, separating the solid and liquid fractions, and reinjecting a liquid stream with a silica content below a preselected level, disclosing a target that meets the "less than about 80 ppm" limitation of claim 9.
  • Key Aspects: Petitioner contended that the dependent claims 10-16 are also anticipated or rendered obvious because they recite arbitrary concentration ranges that are either directly disclosed, encompassed by broader ranges disclosed in Jost, or would have been obvious optimizations of Jost's process for preventing silica scaling.

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

• Prior Art Relied Upon: Maimoni (a 1982 Lawrence Livermore Laboratory technical report).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Maimoni, describing the Hazen pilot plant process for mineral recovery from Salton Sea brines, anticipates or makes obvious all challenged claims. Maimoni discloses obtaining geothermal brine containing silica and iron (II), oxidizing the iron to a ferric state by sparging air through the brine to form ferric hydroxide, and maintaining a pH within the claimed range through the combined effects of air oxidation and the addition of calcium hydroxide. The reference shows the co-precipitation of silica and iron, separation of the precipitate, and reinjection of a liquid fraction with a silica content of 22 ppm, which satisfies the "less than about 80 ppm" limitation. Petitioner further argued Maimoni anticipates claim 15 by explicitly describing a lithium recovery unit in the process.

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

• Prior Art Relied Upon: Wilkins (Patent 4,016,075) and Maimoni (a 1982 technical report).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Wilkins teaches the core method of claim 9. Wilkins describes removing silica from geothermal brine originating from the same Imperial Valley region as the ’827 patent, oxidizing ferrous hydroxide to ferric hydroxide via air lancing, maintaining a pH of 5.3-5.5 (within the claimed range), adsorbing dissolved silica onto the resulting sludge, and reinjecting a filtrate with "less than about 80 ppm" silica. To the extent Wilkins does not explicitly teach the specific concentration ranges recited in the dependent claims, Maimoni provides these details from its documented pilot plant operations.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Wilkins and Maimoni as both address the same long-standing problem of silica scaling in geothermal brines from the same region. A POSITA would look to a detailed technical report like Maimoni, which documents process results from a pilot plant, to optimize the parameters of the general process taught in Wilkins to achieve the specific, albeit arbitrary, concentration levels recited in the dependent claims.
  • Expectation of Success: A POSITA would have a high expectation of success, as applying the process parameters from Maimoni's pilot plant to the similar process in Wilkins involves the predictable application of known techniques to the same type of brine.

• Additional Grounds: Petitioner asserted additional challenges, including anticipation and/or obviousness of claims 9-16 over Wilkins alone, and obviousness over the combination of Jost and Maimoni.

4. Key Claim Construction Positions

• "geothermal brine solution": Petitioner proposed this term be construed as "an aqueous brine solution produced from a geothermal well that contains one or more alkali and/or alkaline earth metal salt(s) having concentrations from trace amounts up to the point of saturation."
• "iron (II) salt": To avoid a chemically impossible construction in hot geothermal brine, Petitioner proposed construing this term as "iron (II) salt or its naturally disassociated constituent components, including ferrous ions and salt ions."
• "iron (III) hydroxide": Petitioner proposed this term be interpreted to include its related chemical forms in solution, namely "iron (III) hydroxide, iron (III) oxyhydroxide, or ferric ions caused by the natural disassociation of iron (III) hydroxide in hot geothermal brine solution."

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 9-16 of the ’827 patent as unpatentable.