30-4 Experimental Determination, and a Thermodynamic Model, of the Solubility of Magnesium Citrate in Concentrated Brines: Applications to Extraction of Magnesium from Produced Water
Session: Geological and Geochemical Investigations of Critical Minerals in New Mexico and Beyond, and Technological Advances in Extraction of Critical Minerals
Presenting Author:
Yongliang XiongAuthors:
Xiong, Yongliang1, Yu, Jianjia2, Xu, Guangping3, Powell, Matt4, Xu, Charles5, Dwyer, Sean6(1) Sandia National Laboratories, albuquerque, New Mexico, USA, (2) New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA, (3) Sandia National Laboratories, Albuquerque, NM, USA, (4) Sandia National Laboratories, Albuquerque, NM, , (5) Sandia National Laboratories, Albuquerque, New Mexico, USA, (6) Sandia National Laboratoriies, Albuquerque, New Mexico, USA,
Abstract:
Produced water contains critical minerals (CMs)/elements such as Li and Mg. In extraction of Li from produced water, divalent ions such as Ca(II) and Mg(II) usually have high concentrations and form scales that interfere the extraction process. Therefore, they must be taken out in a pretreatment process. In our designed pretreatment process with citrate materials, Ca(II) is first precipitated as calcium citrate (earlandite, [Ca3(C6H5O7)2(H2O)2]•2H2O), as earlandite has much lower solubility than magnesium citrate. After Ca(II) is sequestered, higher citrate concentrations are introduced to precipite Mg(II) as magnesium citrate. In this process, the critical mineral/element, Mg(II), is separated and extracted.
To optimize this process, we have conducted solubility measurements on magnesium citrate in order to establish its thermodynamic model, as the thermodynamic model for earlanidte has been established previously. In our solubility measurements at room temperature, the supporting solutions include 0.10 mol•kg–1, 1.0 mol•kg–1, 2.0 mol•kg–1, 3.0 mol•kg–1, 4.0 mol•kg–1, and 5.0 mol•kg‑1 NaCl. All experiments approached the equilibrium/steady state from the direction of undersaturation. Based on our experiments, a thermodynamic model for magnesium citrate in a wide of ionic strengths is developed.
Sandia National Laboratories is a multi-mission laboratory operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA-0003525. This research is funded by the US DOE FECM DE-FE0032491 of the U.S. Department of Energy. SAND2025-15286A.
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Experimental Determination, and a Thermodynamic Model, of the Solubility of Magnesium Citrate in Concentrated Brines: Applications to Extraction of Magnesium from Produced Water
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Topical Sessions
Description
Session Format: Oral
Presentation Date: 5/19/2026
Presentation Start Time: 02:30 PM
Presentation Room: Alvarado B
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