Séminaire ISTerre

Acid Mine Drainage in The Iberian Pyrite Belt: Origin, Remediation and Waste Valorization

jeudi 14 janvier 2021 - 11h00
Carlos Ayora - Institute of Environmental Assessment and Water Research, CSIC, Barcelona
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The Iberian Pyrite Belt (SW Spain and S Portugal) is one of the largest massive sulfide provinces in the world with estimated original reserves of 1700 Mt. Thousands of years of mining have resulted in large number of wastes and more than one hundred orphan sources of high-acidity mine drainage. These drainages have made that the rivers Tinto and Odiel deliver a significant percentage of the global flux of continental metals to the oceans. The Tinto River is acidic from the origin to the estuary, and its geochemistry is controlled by the Fe cycling. The Odiel River, however, carries up to five times more water, and it is initially neutral. The alkalinity of the Odiel River neutralizes the first acid tributaries. Downstream, due to the progressive exhaustion of its alkalinity, the Odiel River becomes acidic to the estuary. The future use of the water for agriculture requires the neutralization of the main acidic drainages. Present day passive remediation systems are based on fine-grained limestone sand dispersed on the surface of a coarse inert matrix of wood shavings. Limestone dissolution raises pH to values around 6 and Fe(III) and then Al oxyhydroxides precipitate. The high porosity of the wood shavings allocates the new precipitates maintaining a high hydraulic conductivity. The accumulation of wastes from AMD treatment motivates the research for their valorization in a circular economy perspective. Thus, scandium, yttrium and lanthanides are entirely retained within the Al oxyhydroxide waste with rates similar to rare earth deposits in clays.

Equipe organisatrice : Grands Séminaires ISTerre

Séminaire uniquement en visio

Informations de visio :

https://univ-grenoble-alpes-fr.zoom.us/j/91302911459?pwd=OTJvYTVPenQxS1FpWVhzQ0tBc1BmUT09

ID de réunion : 913 0291 1459
Code secret : 661771