Abstract: Process for the stabilization of mercury metal by reaction of the mercury metal with sulphur in the solid state, in which the mercury and the sulphur are brought into contact, at an Hg/S molar ratio of 1/1 to 1/3, in a reactor integral with a hollow pipe in fluid communication with the interior space of the said reactor, the said hollow pipe comprising a first end connected to the wall of the said reactor and a second end distant from the said reactor; the said hollow pipe and the said reactor being hermetically sealed, the said hollow pipe being provided with rotating means external to the said pipe and to the said reactor for rotating the said reactor and the said pipe around the axis of the said pipe, and the said hollow pipe being provided, at its end distant from the reactor, with means for introducing the sulphur and the mercury inside the reactor and discharging the reaction products.

Abstract: An organomineral decontamination gel that is used to decontaminate surfaces, in particular metal surfaces. The organomineral gel is made up of a colloid solution containing the combination of a mineral viscosing agent and an organic viscosing agent (coviscosant) chosen from among hydrosoluble organic polymers and surfactants. The presence of an organic viscosing agent improves the rheological properties of gels and substantially reduces their mineral content which generates smaller quantities of solid waste. A decontamination process for metal surface which entails applying the organomineral gel onto the surface to be decontaminated, maintaining this gel on the surface and removing the gel from the surface in particular by rinsing is also provided.