AGROMINING: PRODUCING NI SALTS FROM THE BIOMASS
OF HYPERACCUMULATOR PLANTS
* M.O. Simonnot 1
G. Echevarria 2
, B. Laubie
, J.L. Morel
1 , X. Zhang 1,2 , V. Houzelot 1 , F. Ferrari 1 , J. Rodrigues 1 , M.N. Pons 1 , A. Bani 3 ,
1 LRGP, Université de Lorraine-CNRS, 1 rue Grandville, 54001 Nancy, France
(*Corresponding author: firstname.lastname@example.org)
2 LSE, Université de Lorraine-INRA, TSA 40602, 54518 Vandoeuvre-lès-Nancy, France
3 AE Department, Agricultural University of Tirana, Kodër-Kamëz, Albania
More than 400 plants in the world are able to accumulate nickel in their aerial parts at concentrations higher than 10 g per kg of dry biomass. Then, nickel (Ni) can be recovered from the biomass of these hyperaccumulator plants. Agromining is a chain consisting in growing such plants and recovering metal, it has been developed thanks to the combined know-how of agronomy and hydrometallurgy. Plants can be grown on serpentine soils, containing rather high concentrations of Ni, on sterile heaps or on contaminated soils. This crop enables us to extract Ni from secondary resources, and to improve soil quality by lowering its metal content. For example, Alyssum murale can be grown at the field scale in the Balkans, at yields corresponding to 110 kg Ni per hectare.
Hydrometallurgical processes have been designed from the lab scale to the pilot scale to produce nickel salts: ANSH (ammonium and nickel sulfate hexahydrate), nickel sulfate, acetate and so on. These salts are used for surface treatment and in the paint and chemical industry. Ni salts are prepared from ashes, after plant calcination. Processes are based on the conventional methods of hydrometallurgy: acid leaching followed by different precipitation steps. These processes will be presented, as well as the pilot scale design. Also a life cycle assessment has been performed and clearly shows the environmental interest of this approach. An economic assessment has proved process feasibility and the final step is the launching of a start-up.
At the moment, the approach is widened to other metals (cadmium, cobalt) and elements (REEs).
Nickel salts, hydrometallurgy, hyperaccumulator plant, life cycle assessment, phytomining