The geochemistry of Ni in lateritic profiles and its relationship with the hosting minerals.


The laterite deposits placed in the Caribbean contain a significant amount of Ni.  Despite their geological relevance and economical interest, no detailed studies existed with regards to the mobility of Ni and its incorporation in their hosting minerals along the profiles. In the present talk, a set of results obtained by means of EMPA, µRAMAN, µXRF and µXAS from oxide type laterites from Cuba and silicate type laterites from Dominican Republic are presented. We studied the distribution of Ni in the limonitic and in garnieritic horizons to elucidate how Ni is accumulated in Mn-oxyhidroxides and within the Mg-hydrated phyllosilicates. The obtained results helped to explain the distribution and accumulation of Ni and the development of laterites from Moa-Bay and Falcondo Ni-laterite deposits. These studies also highlight how physicochemical factors such as soil porosity, pH regime and silica activity do have important implications for Ni accumulation and mobility across the profile.

Citing the lecturer, Josep Roqué Rosel himself:

“My research is focused on the measurement of the structure and chemistry of inorganic materials, with the goal of understanding and predicting their properties down to molecular levels. These in turn fundamentally control a wide range of geological and technological phenomena. I work primarily on ordered and disordered materials, including minerals, glassy silicates and ceramics. My primary research tools are X-ray Absorption Spectroscopy (XAS) and Transmission Electron Microscopy (TEM). The materials that I study are natural samples or are synthesized in the laboratory. The problems that I address are tied to large-scale processes in geology and geochemistry, as well as to those in high-tech industries. Among the former are the mechanisms involved in lateritic profile development and the accumulation of metals in soils; among the latter are the study of glasses, the study of the decay by-products in batteries and the optimization of catalysts.”