Recovery of Critical Metals from Aqueous Sources

Abstract

Critical metals, identified from supply, demand, imports, and market factors, include rare earth elements (REEs), platinum group metals, precious metals, and other valuable metals such as lithium, cobalt, nickel, and uranium. Extraction of metals from U.S. saline aqueous, emphasizing saline, sources is explored as an alternative to hardrock ore mining. Potential aqueous sources include seawater, desalination brines, oil- and gas-produced waters, geothermal aquifers, and acid mine drainage, among others. A feasibility assessment reveals opportunities for recovery of lithium, strontium, magnesium, and several REEs from select sources, in quantities significant for U.S. manufacturing and for reduction of U.S. reliance on international supply chains. This is a conservative assessment given that water quality data are lacking for a significant number of critical metals in certain sources. The technology landscape for extraction and recovery of critical metals from aqueous sources is explored, identifying relevant processes along with knowledge gaps. Our analysis indicates that aqueous mining would result in much lower environmental impacts on water, air, and land than ore mining. Preliminary assessments of the economics and energy consumption of recovery show potential for recovery of critical metals.

Recent Advances in the Lithium Recovery from Water Resources: From Passive to Electrochemical Methods

“…Its total amount is estimated to be of 231 Gigatons and both Bardi and more recently Can Sener et al deemed its recovery from seawater economically feasible. [28,30] Moreover, although seawater compo-sition varies due to tides, temperature, and geographical factors, its composition is fairly homogeneous and would not result in a degradation of the purity grade of the mineral harvested. Although high amounts of energy would be required, a significant decrease of cost can be obtained by coupling this kind of extraction with desalination plants and using the retentate of such industrial plants.…”

Systematic Assessment of Precious Metal Recovery to Improve Environmental and Resource Protection

“…Waste household appliances and e-waste contain rich precious metal resources, which are called “urban mines” . Waste garbage not only contains wastes resources but also causes serious pollution to the environment …”

Rapid Spectrometer-Free Luminescence-Based Detection of Tb3+ and Eu3+ in Aqueous Solution for Recovery and Urban Mining

“…29,30 Detection of rare earth elements in materials is essential, both for extraction and also for an evaluation of their mining potential by geochemical exploration studies. 3,9 Furthermore, after the separation of lanthanide mixtures, quality control is desired, e.g., for Dy 3+ and Nd 3+ , 31−33 both present in several types of Fe/Nd/B magnets.…”

“…These elements play a significant role in the modern world, being used in permanent magnets, catalysts, lasers, battery alloys, phosphors, and more. − This covers multiple application areas: green technologies, medical science, lifestyle, and defense sectors. − Rare earth elements are considered as critical resources worldwide, e.g., by the U.S. Department of Energy and the European Commission . For sustainability of the usage of rare earth elements, it is important to increase material efficiency, recovery, and recycling. − …”

“…Recovery of lanthanide ions such as Nd 3+ can be achieved, e.g., from isolated components, such as Fe/Nd/B magnets. − In addition, significant concentrations of various lanthanide ions can be found in mining and wastewaters. ,− Trivalent lanthanide recovery of Eu 3+ and Tb 3+ are typically studied at concentrations of 0.3–5 mM (50–800 mg·L –1 ). − Examples for higher concentrations (5–50 mM, 0.8–7.5 g·L –1 ) are reported as well. − Trace concentrations (0.03–0.06 mM, 5–8 mg·L –1 ) of lanthanides such as the expensive terbium are also the subject of several recovery studies. − Generally, recovery dwindles as concentrations decrease. As of today, recovery is not possible by the majority of methods below a threshold concentration of trivalent lanthanides, which is estimated to be approximately <5 μM (<0.1 mg·L –1 ).…”