Geologic leaching

Salt cavities Where the geological formation is favorable, it is possible to leach out salt to create underground... 

The geological cycle sediments from deep regions of the Earth, which are subject to high pressure and high temperature, are brought back to the Earth s surface by geological dynamics. The metamorphic rock is more labile than the starting material and can be leached more easily, so that a cycle is set up in which new clay species are formed. 

Leach, D. L., G. S. Plumlee, A. H. Hofstra, G. P. Landis, E. L. Rowan and J. G. Viets, 1991, Origin of late dolomite cement by C02-saturated deep basin brines evidence from the Ozark region, central United States. Geology 19, 348-351. 

McClenaghan, M.B., Hamilton, S.M., Hall, G.E.M., Burt, A.K., Kjarsgaard, B.A. 2006. Selective Leach Geochemistry of Soils Overlying the 95-2, B30, and A4 Kimberlites, Northeastern Ontario. Geological Survey of Canada, Open File 5069. 

Hall, G.E.M., Vaive, J.E., Beer, R., Hoashi, M. 1996. Phase selective leaches for use in exploration geochemistry. In EXTECH I a multidisciplinary approach to massive sulphide research in the Rusty Lake-Snow Lake greenstone belts, Manitoba. Geological Survey of Canada Bulletin, 169-200. 

Leach, D.L. et al. 2005. Sediment-hosted lead-zinc deposits a global perspective. Economic Geology 100th Anniversary Volume, 561-608. 

Since the water movement will be very slow compared with the rate at which the wastes dissolve, we are concerned first and foremost with equilibrium solubility. Also, if only to relate behaviour on the geological time scale to that on the laboratory time scale, we will need to know about the mechanisms and kinetics of dissolution and leaching. The waste forms envisaged at present are glass blocks containing separated fission products and residual actinides fused into the glass and, alternatively, the uranium dioxide matrix of the used fuel containing unseparated fission products and plutonium. In the... 

Nasraoui, M., Toulkeridis, T., Clauer, N. Bilal, E. 2000. Differentiated hydrothermal and meteoric alterations in the Lueshe carbonatite complex (Democratic Republic of Congo) identified by a REE study combined with a sequential acid-leaching experiment. Chemical Geology, 165, 109-132. 

Tazaki, K., Fyee, W. S. Djssanayake, C. B. 1987, Weathering of apatite under extreme conditions of leaching. Chemical Geology, 60, 151-162. 

Leaching of Fully Radioactive High-Level Waste Glass and Waste-Geologic Environment Interaction Studies... 

Release rate data from actual radioactive waste forms is needed to evaluate the safety of emplacing nuclear wastes in geologic media. However, in addition to waste form development studies, such as the leach test just described, a comprehensive program was started to obtain release data from candidate waste forms for geologic disposal. 

The use of inorganic ion exchangers to solidify liquid radioactive waste followed by pressure sintering to produce a ceramic waste form appears to be a viable alternative to calcina-tion/vitrification processes. Both the process and waste form are relatively insensitive to changes in the composition of the waste feed. The stability of the ceramic waste form has been shown to be superior to vitrified wastes in leaching studies at elevated temperatures. Further studies on the effects of radiation and associated transmutation and the influence of temperature regimes associated with potential geologic repositories are needed for a more definitive comparison of crystalline and amorphous waste forms. 

T1he adsorption of metal ions from aqueous solutions is a phenomenon of immediate interest to workers in many diverse disciplines. The incorporation of metals into geological sediments, removal of metal ions from industrial and civic effluent, interference of trace metal ions in analytical and electroanalytical chemistry, ore flotation, metallurgical leaching processes, and the stability of ceramic slips are all processes which are controlled to a large extent by interaction of metal ions with solid-liquid interfaces. 

Gilbert, S.E., Cooke, D.R. and Hollings, P. (2003) The effects of hardpan layers on the water chemistry from the leaching of pyrrhotite-rich tailings material. Environmental Geology, 44(6), 687-97. 

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