Some lithium could come from wastewater

Some lithium could come from wastewater
pitt.edu

Maybe that's step one, but of course the real question is whether it can be accessed economically. The paper mostly doesn't discuss economics, and indeed the only reason the research appears to have been done is because there is a regulatory requirement to have the wastewater analyzed (as opposed to, e.g., being done because the company thinks it's possibly economically valuable).

Here's the abstract of the research article:

> Decarbonatization initiatives have rapidly increased the demand for lithium. This study uses public waste compliance reports and Monte Carlo approaches to estimate total lithium mass yields from produced water (PW) sourced from the Marcellus Shale in Pennsylvania (PA). Statewide, Marcellus Shale PW has substantial extractable lithium, however, concentrations, production volumes and extraction efficiencies vary between the northeast and southwest operating zones. Annual estimates suggest statewide lithium mass yields of approximately 1160 (95% CI 1140–1180) metric tons (mt) per year. Production decline curve analysis on PW volumes reveal cumulative volumetric disparities between the northeast (median = 2.89 X 107 L/10-year) and southwest (median = 5.56 × 107 L/10-year) regions of the state, influencing lithium yield estimates of individual wells in southwest [2.90 (95% CI 2.80–2.99) mt/10-year] and northeast [1.96 (CI 1.86–2.07) mt/10-year] PA. Moreover, Mg/Li mass ratios vary regionally, where NE PA are low Mg/Li fluids, having a median Mg/Li mass ratio of 5.39 (IQR, 2.66–7.26) and SW PA PW is higher with a median Mg/Li mass ratio of 17.8 (IQR, 14.3–20.7). These estimates indicate substantial lithium yields from Marcellus PW, though regional variability in chemistry and production may impact recovery efficiencies.

https://www.nature.com/articles/s41598-024-58887-x

Discouragingly, they say:

> Further, extraction of Li from [wastewater] with high Mg/Li mass ratios (> 6), such as in [southwest Pennsylvania], is less efficient and expensive relative to low Mg/Li extraction methods31. The low Mg/Li composition of [northeast Pennsylvania] produced waters are comparable to salar brines, such as the Atacama brines of Chile, which are favorable to more economical and sustainable evaporative and distillation Li recovery methods. As a result, the higher Li yields from [southwest Pennsylvania] wells may be more costly to extract due to the lower concentrations and reduced treatment efficiencies due to the high Mg/Li nature of these waters.

Also

> Another important consideration in the total Li yield of a reservoir is the well production decline rate. A typical Marcellus well has an 80% decline in production of water within it’s the first 2 years (SI 4.). Sustainable production of Li at volumes reported in this manuscript require continuous addition of new Marcellus wells to supplant older, less productive wells.