University System of Maryland

University of Sheffield

United States of America, as Represented by the Secretary of Agriculture

Other

The United States of America as Represented by the Secretary of

Massey University

United States Department of Agriculture

Yin-Ming Li

Rufus L Chaney

Jay Scott Angle

J Scott Angle

Alan J M Baker

Alan Jm Baker

Roger D Reeves

The invention relates to recovering metals, such as nickel and cobalt, by phytomining or phytoextracting soils rich in metals wherein the desired metal is selectively accumulated in hyperaccumulator plants by adjusting the soil pH. The metals are ultimately recovered from above-ground plant tissues at economically acceptable levels without further contaminating the metal-containing sites. The invention also relates to metal-hyperaccumulating plants.

Recovering metals from soil

A cadmium and zinc hyperaccumulating subspecies fromand methods for removing or recovering cadmium and zinc from soils by cultivating thesubspecies on soils containing cadmium and zinc.

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The recovery of nickel, cobalt and other metals by phytomining is described. Plants of the Alyssum genus are grown in nickel rich soil. The uptake of nickel is enhanced by maintaining specific soil conditions, including a concentration of calcium between (but not including) 0.128 mM an 5.0 mM and an acidic pH. Ni uptake may be further enhanced by maintaining a ratio of exchangeable Ca/Mg of 0.16-0.40. Uptake may be further enhanced by addition of chelating agents and ammonium based fertilizers.

Method for phytomining of nickel, cobalt and other metals from soil

Nickel/cobalt, as well as platinum and palladium metal family members are recovered from soil by growing Brassicaceae plants, specifically Alyssum in soil containing nickel/cobalt as well as other metals. The soil is conditioned by maintaining a low pH, low calcium concentration, and the addition of ammonium fertilizer and chelating agents thereto. Nickel accumulation on the order of 2.5 percent or better in above-ground tissues is achieved, which permits recovery of the metal by harvesting the above-ground plant materials, drying, and then combusting the same, to oxidize or vaporize organic materials and recover the metals sequestered therein at 10-20 fold higher concentrations than in the soil, in a form which can be used in conventional Ni refinery or smelting operations.

Growing community of inventors

Potomac, MD, United States of America

Yin-Ming Li