LU87526A1 - SEPARATOR FOR AN ACID ELECTROLYZER OF TRITIATED WATER AND METHOD FOR MANUFACTURING SUCH A SEPARATOR - Google Patents

Description

SEPARATOR FOR AN ACID ELECTROLYZER OF TRITIATED WATER AND METHOD FOR MANUFACTURING SUCH

SEPARATOR The invention relates to a separator for an acid electrolyser of tritiated water consisting of a support and an impregnation of this support.

For a separator applicable to the acid electrolysis of tritiated water, chemical stability with respect to acid solutions and with respect to Beta radiation is above all required.

Document UK-A 2,045,804 discloses a method for preparing a separating membrane consisting of a powder of polyantimonic acid and an organic binder such as polysulfone. Such a separator degrades quickly under the influence of Beta radiation from tritiated water.

The object of the invention is to provide a separator for an acidic water electrolyser which better resists the Beta radiation of highly tritiated water. Another object of the invention is to propose a method of manufacturing such a separator.

According to the invention, the separator, which consists of a support and an impregnation of this support, is characterized in that said support is a microporous ceramic body and that the impregnation material is polyantimonic acid Sb203 .nH20.

The method of manufacturing such a separator is characterized in that the ceramic body is first immersed in a solution of antimony chloride SbClß in 1,2-dichloroethane, which is then dried the body in air dry and put in water to convert the antimony chloride to polyantimonic acid.

As regards preferred examples of implementation of the invention, reference is made to the subclaims. The invention will be described below in more detail with the aid of a few examples.

Example 1

An alumina support with a thickness of 3.05 mm is prepared. The water retention rate of such a support is 19.75% (weight of the water absorbed / total weight of the sample).

This support is treated with a solution of the following composition: 10 ml 1,2-dichloroethane 15 g SbCl3

The molar ratio SbCl3 / l, 2-dichloroethane is 0.0657 / 0.127. ''

Throughout the treatment, the temperature is kept constant at 20 ° C and the treatment time is 24 hours. After that, the sample is extracted from this solution and the solvent is removed by evaporation for 24 hours at room temperature, 20 minutes in an oven at 60 ° C and then 48 hours at room temperature. Then, the sample is immersed in distilled water at room temperature for 24 hours, then dried in a vacuum oven at a temperature of 70 ° C. This gives the in situ conversion of antimony chloride to the corresponding hydrated oxide (polyantimonic acid). When weighing the sample, the weight increase of 18% compared to the initial weight is observed.

To determine the water retention of such a separator, it is introduced into distilled water for 72 hours and then it is observed that the weight has increased by 17.4% relative to the weight of the dry sample. The voltage drop measured in an electrolysis cell whose electrolyte is a 20% aqueous solution of sulfuric acid and which is subjected to a continuous voltage amounts to 3.7 cm 2 at 40 ° C and to 3.1

cm2 at 60 ° C.

Example 2

A support with the same characteristics as that of example Nr. 1 is immersed in a solution of the following composition: 10 ml of 1,2-dichlorethane 20 g of SbCl3

The SbCl3 / 1.2-dichloroethane molar ratio is 0.0876 / 0.127.

The impregnation method and the conversion of antimony chloride to polyantimonic acid are carried out in the same way as that described for example Nr. 1. The sample thus obtained is 15.8% heavier than the initial support. The voltage drop measured in a cell identical to Example 1 is 2.4

cm2 at 40 ° C, 2.1,

cm2 at 60 ° C and 1.9

cm2 at 80 ° C. The water retention rate is 17.3% by weight relative to the dry sample.

Example 3

The manufacturing conditions are the same as for the previous examples except for the impregnation solution, the composition of which is as follows: 10 -ml 1,2-dichloroethane 10 g SbCl3, the molar ratio being 0.0438 / 0.127.

The weight of the sample increased by 18.5% compared to the weight of the support alone.

Such a sample has the following characteristics; the water retention rate is 18.4% compared to the dry sample. The voltage drop of this separator in an electrolysis cell as defined above amounts to 7.5

cm2, 5, 2

cm2 and 4.0

cm2 at 40 ° C, 60 ° C or 80 ° C respectively.

Since the components of the separator according to the invention are inorganic, this separator resists well to Beta radiation up to 30 Curie / cm 3, radiation which would cause rapid destruction of a separator according to the prior art.

Claims (6)

1. Separator for an acid electrolyser of tritiated water consisting of a support and an impregnation of this support, characterized in that said support is a microporous ceramic body and that the impregnation material is polyantimonic acid Sb203.nH20. 2. Separator according to claim 1, characterized in that the support material is chosen from alumina, silicon nitride and silicon carbide. 3. Method of manufacturing a separator according to one of claims 1 and 2, characterized in that the ceramic body is first immersed in a solution of antimony chloride SbCl3 in 1,2-dichloroethane, then the support is dried in dry air and placed in water to convert the antimony chloride to polyantimonic acid. 4. Method according to claim 3, characterized in that the ceramic body is immersed in said solution for a period between 1 hour and 24 hours. 5. Method according to claim 4, characterized in that then the body is dried for several hours in dry air or in vacuum at room temperature. 6. Method according to claim 5, characterized in that then the body is heated for one hour to about 60®C.