Method for electrokinetic decontamination of a porous solid medium

A method for electrokinetically removing contaminating species from a depth of a porous solid material coming from a nuclear installation, which method comprises:

• a) applying to a first external surface of the porous solid material a first layer of an electrolyte and a first electrode, and to a second external surface of the porous solid material a second layer of the electrolyte and a second electrode, each of the first and second electrodes being formed by an electrically conducting element, the electrolyte being an essentially inorganic gel comprising from 10 to 40% by mass of an inorganic viscosifying agent, dispersed in 60 to 90% by mass of an aqueous phase with a basic pH and no more than 5% by mass of an organic material, the first layer of the electrolyte ensuring an electrical contact between the first external surface and the first electrode and the second layer of the electrolyte ensuring an electrical contact between the second external surface and the second electrode;
• b) extracting the contaminating species from the depth of the porous solid material into the first and second layers of the electrolyte, by applying an electric current between the first and second electrodes;
• c) drying the first and second layers of the electrolyte comprising the extracted contaminating species until a first and a second dry residues are obtained which fracture;
• and
• d) removing the first and second electrodes and the first and second fractured dry residues from the first and second external surfaces of the porous solid material.

A method for electrokinetically removing contaminating species from a depth of a porous solid material coming from a nuclear installation, which method comprises:

• a) introducing into a first housing of the porous solid material a first layer of an electrolyte and a first electrode, and into a second housing of the porous solid material a second layer of the electrolyte and a second electrode, each of the first and second electrodes being formed by an electrically conducting element, the electrolyte being an essentially inorganic gel comprising from 10 to 40% by mass of an inorganic viscosifying agent, dispersed in 60 to 90% by mass of an aqueous phase with a basic pH and no more than 5% by mass of an organic material, the first layer of the electrolyte ensuring an electrical contact between a wall of the first housing and the first electrode and the second layer of the electrolyte ensuring an electrical contact between a wall of the second housing and the second electrode;
• b) extracting the contaminating species from the depth of the porous solid material into the first and second layers of the electrolyte, by applying an electric current between the first and second electrodes;
• c) drying the first and second layers of the electrolyte comprising the extracted contaminating species until a first and a second dry residues are obtained which fracture;
• and
• d) removing the first and second electrodes and the first and second fractured dry residues from the first and second housings of the porous solid material.