The New Weapon Against China’s Mineral Dominance: Plants
The search for new suppliers for the minerals needed for everything from batteries to missiles has driven novel extraction methods
By Jon Emont, The Wall Street Journal, Jan. 25, 2025
…
Certain plants, called hyperaccumulators, absorb large quantities of minerals, like nickel and zinc, from the soil. Cultivating these plants, and then incinerating them for their metal, could provide U.S. companies with a small stream of domestically sourced minerals—without the expense and environmental destructiveness of conventional mining…
ARPA-E, an Energy Department agency, is dispensing $10 million to find ways to make nickel farming feasible in the U.S…
At a greenhouse in Amherst, professors are using the funding to undertake gene editing to build a new fast-growing, nickel-absorbing oilseed plant. If successful, the plant could be used to harvest the metal from mineral-rich soils in states such as Maryland and Oregon…The nickel recovered from plants is already in a purer chemical form than that coming from conventional mining, saving on energy-intensive and costly processing. … [end quote]
The production is much lower than actual nickel mines. But it’s environmentally friendly and literally on our own soil. Will it ever become commercially profitable or even feasible at commercial scale? Time will tell.
As the metal (in the plant) is more pure than mined ore, extracting the metal (as part of the complete refining process) will be less expensive than reaching the same purity level with mined ore.
Purity of the metal implies the plant is selective. You expect to recover lead, arsenic, phosphorus, potash, and maybe anything else there. You get a mix that must be separated.
And note that you expect diminishing returns,. As metal content is depleted, recovery decreases.
As with other “recycling” the costs are dependent upon the ease of collection and the concentration. Also, IIRC, the plants used in phytoremediation are rather indiscriminate in their uptake.
Just to throw another log on the fire…
Most plant roots are concentrated in the top 0.5m of soil. Ie, top soil. (Really in the top 0.2m).
Some roots go deeper… Say 2m. But get fewer and fewer in the deeper soils, ie sub soils.
Minerals/elements, pollutants, etc tend to leach downward in the soil profile, accumulating below the “root zone”, and leaching along with water drainage into springs, creeks, rivers, etc.
This means that if the target “mineral/element” or “pollutant” is deeper than … say 1m, then phytoextraction becomes less and less extractive.
Kernza® is the trademark name for the grain of a deep-rooted perennial intermediate wheatgrass (Thinopyrum intermedium) being developed at The Land Institute. The roots can extend 10 feet or more beneath the soil surface, delivering atmospheric carbon to the soil and efficiently taking up nutrients and water.
There are many exciting benefits as a food grain. I’m sure it can be genetically engineered to concentrate metals in the grains which can be harvested.
Wendy
And:
{ Within five years, stands have produced up to 7,000 pounds per acre (7,800 kg/ha) of dry root mass in the top 8 inches (20 cm) of soil.[10] }
From:
Measuring root biomass in the top 0.2m is standard soil science, especially with grasses n prairie species.
Root biomass is like an upside down pyramid. The majority is near the soil surface.
Sure, some roots go deeper but on a percent basis, the biomass deeper than 1m is likely only about 20% (or less).
Deeper than 1.5m… 5%?
Research and tech such as GMO might increase overall root depth.
But, I’m gonna stick with my comment that minerals/elements, pollutants n other soil molecules in soil layers deeper than 1m are less and less accessible by phytoextraction.
I’m willing to amend that to 2m.
Or even 3m. But, effective extraction of a target chemical drops off rapidly.
Wow! That is impressive, especially as getting a plant to do that is harder than manipulating the genes to do simpler stuff, including CO2 capture and metal absorption.
