Patent Number: 051436531
Section: description

The following examples are given to illustrate the invention. EXAMPLE 1 Taking a batch of borate-containing IER in suspension for treatment. Neither the composition of this batch, nor the exact nature of the IER, nor their borates content are known. In actual fact, said IER contain 350 g eq H.sub.3 BO.sub.3 /kg of dry IER, which are anionic Amberlite IRN 78 LCL IER. The batch of IER is placed into a mingler-mixer built by the company GUEDY, to which is coupled a weighing device. After a rest period during which the IER are allowed to decant, the supernatant solution is pumped out. The apparatus is weighed, the weight of 100% decanted IER is determined. 30 l of aqueous solution of Ca(NO.sub.3).sub.2 at 200 g/l are added to the obtained 16.5 kg of 100% decanted IER, together with 0.8 kg of solid lime, the resulting mixture being stirred for one hour. 75 kg of CLK cement are then added under stirring. The whole is mixed, then poured into a container under the normal conditions used for treating wastes with a hydraulic binder. The weight of the resulting coated product is about 120 kg, this representing a rate of incorporation F' of 4% of dry resins, a ratio of total water/cement of 0.5 (total water=water of saturating solution+IER constituting water+interstitial water found in the 100% decanted IER) and a volume increase factor of 4.7. Core samples are taken from said coated product and tested for mechanical strength. Mechanical strength under compression is over 100 bars after 7 days, over 200 bars after 14 days, and over 300 bars after 2.times.28 days. EXAMPLE 2 The same batch as before is decanted, weighed (16.5 kg) and eluted with 21.5 l of a 200 g/l aqueous solution of Ca(NO.sub.3).sub.2 and 51 kg of CLK cement are added. We have then F'=8% (in dry resin) f=3.5 Although incorporation is improved, hardening is reduced since compression strength is under 10 bars after 7 days, and over 200 bars after 28 days. This process, which should be performed with a single apparatus composed of a mixer, and which is applicable to all IER used in nuclear medium, brings considerable simplification at the industrial level in the concreting of radioactive IER. Therefore the process according to the invention offers a number of essential advantages for an industrial application in the nuclear field. One of them is that it prevents the transfer of active materials: only the wastes to be treated are brought to the site. There is no need for any extraction, apart from the casting of the final product in a container, or for any parallel treatments of extracted effluents. This because the whole of the treatment can be carried out in one single apparatus: the mixer. The second advantage is the easy implementation of the process. For example, IER arrives, and nothing is known about it. It can be immobilized in a satisfactory way in conformity with the applicable safety standards. The only thing to do is to determine its weight in the decanted state and to remain withing the ranges of values prescribed by the process according to the invention. As to elution, this is an easy operation. Easy operations and simple apparatuses are sought in the nuclear field where the slightest problem raises difficulties as to man's intervention (manual handling on site) and as to the decontamination and the containment of the radioactive materials. A third advantage is to be able to treat any type of IER originating from a nuclear installation, whether or not it contains borates, even in large quantity. Thereagain there is uniqueness in the treatment. It should be noted that the ranges of F and F' are not essential features of the novel process of the invention and are merely the observed results obtained in the end product. A latitude of modification, change and substitution is intended in the foregoing disclosure, and in some instances, some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein described.