The potential for geothermal lithium in Italy

<p>Italy has never been a lithium (Li) producer, and the potential for &#8220;hard rock&#8221; deposits is moderate at best. On the other hand, the increasing demand for Li-based rechargeable batteries fostered new interest in this metal, and prompted the quest for alternative resources. The extraction of Li from geothermal brines (&#8220;geothermal lithium&#8221;) is currently considered in several countries, including, in Europe, France, Germany, and UK (EGEC, 2020).</p><p>Italy has vast geothermal resources, and there is a potential for &#8220;geothermal lithium&#8221; as well. A preliminary survey of literature data pointed out several occurrences of fluids with Li contents up to hundreds of mg/L. Among high-enthalpy fluids, we point out those of Cesano, Mofete, and Latera. At Cesano, geothermal fluids contain about 350 mg/L lithium (Calamai et al., 1976). Early studies conducted in the past century (Pauwels et al., 1990) suggested the feasibility of lithium recovery from these fluids. Even higher contents (480 mg/L) occur in the deep reservoir at Mofete (Guglielminetti, 1986), whereas fluids in the shallow and intermediate reservoir in the same field contain 28 to 56 mg/L. Geothermal fluids at Latera have somewhat lower contents (max 13.5 mg/L; Gianelli and Scandiffio, 1989). Several low-enthalpy thermal waters in Emilia-Romagna, Sardinia, Sicily and Tuscany also show significant (> 1 mg/L) Li contents (max 96 mg/L at Salsomaggiore; Boschetti et al., 2011). There are no published Li data for high-enthalpy fluids at Larderello; however, evidence of Li-rich fluids was found in fluid inclusions in hydrothermal minerals (Cathelineau et al., 1994). Moreover, the shallow (ca. 3.5 km) granitoid body underlying the field contains a Li-rich (about 1,000 ppm) biotite (A. Dini, unpublished data); it has been estimated that such rock may contain as much as 500 g Li per cubic meter.</p><p>&#160;</p><p>References</p><p>Boschetti T., et al. - Aquat Geochem (2011) 17:71&#8211;108</p><p>Calamai A., et al. <strong>- </strong>Proc. U.N. Symp. Development Use Geotherm. Energy, S. Francisco, USA&#160;(1976), 305-313</p><p>Cathelineau M., et al. &#8211; Geochim. Cosmochim. Acta (1994) 58: 1083-1099</p><p>EGEC (European Geothermal Council). https://www.egec.org/time-to-invest-in-clean-geothermal-lithium-made-in-europe/. Accessed December 2, 2020.</p><p>Gianelli G., Scandiffio G. - Geothermics (1989) 18: 447-463</p><p>Guglielminetti M. - Geothermics (1986) 15: 781-790</p><p>Pauwels H., et al. - Proc. 12th New Zealand Geothermal Workshop (1990), 117-123</p>