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Energies 2021, 14, 6805 49 of 72 used to selectively extract and recover potassium from geothermal brines at 95 ◦C. It was concluded that ion exchange could be used to recover potassium from geothermal brine; however, the overall process was not considered cost effective [129,130]. Potash recovery from geothermal brines was proposed for the Cerro Prieto geothermal field [278]. 3.3.2. Alkaline Earth Metals Commercial deployment of molecular sieve sorbents in mineral recovery has been hampered by the cost of conditioning feedstock (pretreatment) to remove alkaline earth metals, particularly calcium and magnesium [128]. Separation of lithium from magne- sium is critical to achieving high recovery efficiency and purity of the final lithium prod- uct [17,120,128,262]. For example, the richest lithium resource in the world, the Uyuni salar brine, contains a high magnesium concentration (Table 1), which causes difficulties in lithium production [56]. Calcium and magnesium may be removed from brine by a variety of methods and magnesium has a significant resource value if it can be recovered as magnesium oxide as part of a lithium extraction and recovery process. Removal of magnesium and calcium adds cost to lithium recovery [57,279]. Xu et al. [17] reviewed methods for separating magnesium and lithium in the context of recovering lithium from salt lake brines. Techniques for the separation of magnesium from lithium include precipitation, adsorption, solvent extraction, nanofiltration membrane, electro- dialysis, and electrochemical methods [17]. Xu et al. [17] concluded that a combination of techniques would be needed in order to achieve the high separation selectivity, stability, low cost, and environmentally friendly characteristics needed for successful lithium extraction. Ion-exchange resins may be applied for the separation of alkaline earth metals from alkali metals [59,280,281]. For example, Nishihama et al. [59] extracted lithium from seawater with a granulated-MnO2 adsorbent, with a recovery efficiency of lithium of approximately 33% and then purified the eluent stream with a strongly acidic cation- exchange resin to remove divalent metal ions, then removed sodium and potassium with a diketone/TOPO impregnated resin, and lastly recovered lithium as precipitates of Li2CO3 using a (NH4)2CO3 saturated solution. The yield of recovered Li2CO3 with their process was 56% with more than 99.9% purity [59]. Separation of lithium from divalent cations can also be achieved by precipitation. Bukowsky et al. [58] demonstrated that precipitation followed by ion exchange can be effectively used for separation and recovery of lithium from a synthetic solution of calcium and magnesium chlorides. Laitala et al. [282] proposed using precipitation and solvent extraction to prepare brines for lithium extraction. The process for producing a clean lithium solution involves first-stage magnesium and calcium removal by bulk precipitation of carbonates, sulfates or hydroxides with sodium carbonate or calcium hydroxide. This is followed by a second-stage polishing step of selective liquid–liquid extraction using a dialkyl phosphoric acid mixture (e.g., di-2-ethyl hexyl phosphoric acid) to remove residual calcium and magnesium from the lithium-containing solution. After the extraction step, magnesium and calcium concentrations in the aqueous phase are reported to be less than 0.01 g/1 [282]. Perez et al. [273] used two-stage precipitation of magnesium with calcium hydroxide to precipitate virtually all of the magnesium in the form of magnesium hydroxide, but also significant quantities of calcium in the form of gypsum (CaSO4·2H2O) and boron in the form of calcium borate (CaB2O4·6H2O). Magnesium can be removed from lithium brines by using oxalic acid precipitation. The resulting Mg-oxalate that was removed from the brine was suitable for the production of magnesium oxide by roasting [56]. Li and Binnemans [283] tested neodecanoic acid and D2EHPA as co-extracts to remove magnesium from concentrated brines in the context of producing battery-grade Li2CO3 and found that this solvent mixture could remove over 85% of the magnesium, but also extracted up to 6% of the lithium. A mixture of the beta-diketone HPMBP and Cyanex 923 were more selective for magnesium extraction over lithium, yielding a separation factor of over 1000 [283]. Other beta-diketones (HTTA and HDBM) were not as effective.PDF Image | Recovery of Lithium from Geothermal Brines
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ORC Waste Heat Turbine and ORC System Build Plans: All turbine plans are $10,000 each. This allows you to build a system and then consider licensing for production after you have completed and tested a unit.Redox Flow Battery Technology: With the advent of the new USA tax credits for producing and selling batteries ($35/kW) we are focussing on a simple flow battery using shipping containers as the modular electrolyte storage units with tax credits up to $140,000 per system. Our main focus is on the salt battery. This battery can be used for both thermal and electrical storage applications. We call it the Cogeneration Battery or Cogen Battery. One project is converting salt (brine) based water conditioners to simultaneously produce power. In addition, there are many opportunities to extract Lithium from brine (salt lakes, groundwater, and producer water).Salt water or brine are huge sources for lithium. Most of the worlds lithium is acquired from a brine source. It's even in seawater in a low concentration. Brine is also a byproduct of huge powerplants, which can now use that as an electrolyte and a huge flow battery (which allows storage at the source).We welcome any business and equipment inquiries, as well as licensing our turbines for manufacturing.CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)