Abstract: The present invention relates to a process for treating a waste containing asbestos, comprising a step (E) in which the asbestos contained in said waste is dissolved by reacting this waste with an acid other than hydrofluoric acid, preferably with hydrochloric acid, at a temperature of at least 125° C. and at a pressure greater than 0.2 M Pa (2 bar), and in which: the asbestos included in the treated waste is an asbestos of amphibole type; and/or the solution obtained at the end of the acid dissolution of the asbestos is reused, for example for the synthesis of apatites.

Abstract: The invention relates to the containment of caesium and/or rubidium, in particular 135Cs and 137Cs in an apatitic matrix of formula: MtCaxLny(PO4)6−u(SiO4)uX in which: M represents Cs and/or Rb, Ln represents at least one trivalent cation, X represents at least one anion chosen from among 2F−, S2−, 2Cl−, 2Br−, 2I−, 2OH− and O2−, and t, x, y, and u are such that: 0<t·2.5 2·x·8 1·y·7 0·u·6 x+y+t=10 and the total number of positive charges provided by the cations M, Ca and Ln are equal to (20+u).

Abstract: The invention involves a process for containment of industrial wastes, particularly nuclear wastes, in apatite ceramics. This process involves preparing a homogeneous mixture of powders which can form an apatite matrix, introducing the waste into this mixture, compacting it under a pressure of 100 to 500 MPa at room temperature, and subjecting it to hydrothermal processing at low temperature (100 to 500° C.) in the presence of water in a sealed chamber.

Abstract: A process for manufacturing an apatite ceramic, especially for biological use involves the preparation of a homogeneous mixture of powders to form a hydroxyapatite of formula Ca10(PO4)6(OH)2, stoichiometric or non-stoichiometric, possibly containing other additives or flaws, compacting the mixture under a pressure of 100 to 500 Mpa at room temperature, and subjecting it to hydrothermal treatment at low temperature (100 to 500° C.) in the presence of water and in a sealed chamber.

Abstract: The invention relates to a process for the conditioning of radioactive waste using silicated apatites as the confinement matrix.This process consists of incorporating the waste (1) into a phosphosilicated apatite-based confinement matrix (3) e.g. complying with the formula:M.sub.t Ca.sub.x Ln.sub.y A.sub.z (PO.sub.4).sub.u (SiO.sub.4).sub.6-u X (I)in which M is an alkali metal, Ln a rare earth, A an actinide, X is S.sup.2-, 2F.sup.-, 2Cl.sup.-, 2Br.sup.-, 2I.sup.- or 2OH.sup.- and u is between 0 and 6.

Abstract: The invention relates to the conditioning or packaging of radioactive iodine, particularly iodine 129, using an apatite as the confinement matrix. Having the iodine, said apatite corresponds to the formula:M.sub.10 (XO.sub.4).sub.6-6x (PO.sub.4).sub.6x I.sub.2 (I)in which M represents Cd or Pb, X represents V or As, I is the radioactive iodine to be conditioned and x is such that 0.ltoreq.x<1. This iodoapatite (1) can be surrounded by an apatite (3) not containing iodine serving as a physical barrier.The iodoapatite can be obtained from a solid compound of the iodine, e.g. an iodide such as silver iodide or lead iodide, by reaction with a compound of formula:M.sub.3 (XO.sub.4).sub.2-2x (PO.sub.4).sub.2x (II)orM.sub.10 (XO.sub.4).sub.6-6x (PO.sub.4).sub.6x Y.sub.2 (III)in which M, X and x are as defined hereinbefore and Y can represent OH, F, Cl or O.sub.1/2.

Abstract: The invention relates to a process for the treatment of natural apatites with a view to the use thereof for storing irradiated fuel elements.This process consists of contacting a natural apatite powder with an acid aqueous solution, e.g. dilute HNO.sub.3 or HCl for between a few seconds and 10 minutes.In this way, the physicochemical properties of the natural apatite are improved by modifying its surface composition in order to make it close to that of hydroxyapatite. This modified apatite can be used as a filling material in irradiated fuel element storage containers.

Abstract: The invention relates to a process for the treatment of natural apatites with a view to the use thereof for storing irradiated fuel elements.This process consists of contacting a natural apatite powder with an acid aqueous solution, e.g. dilute HNO.sub.3 or HCl for between a few seconds and 10 minutes.In this way, the physicochemical properties of the natural apatite are improved by modifying its surface composition in order to make it close to that of hydroxyapatite. This modified apatite can be used as a filling material in irradiated fuel element storage containers.