JPH1194994A - Method for removing uranium and TRU from uranium and TRU-containing liquid - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To easily remove uranium and TRU from waste liquid and to reduce the volume of the removed waste. SOLUTION: Tannic acid is added to an aqueous solution containing at least one element of uranium or TRU to form a compound of tannic acid and the above-mentioned element such as uranium. Uranium or TRU is separated from mother liquor by adsorption on activated carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for removing uranium and TRU from a liquid containing uranium and TRU.

[0002]

2. Description of the Related Art At nuclear power plants and nuclear research facilities,
Trace amounts of uranium and TRU (transuranium elements such as Pu and Am)
Various liquids containing are produced. It is important to remove uranium and the like from these liquids, and as a currently practiced removal method, an ion exchange method or the like is mainly used for a simple solution.

On the other hand, in wastewater to be washed, such as contaminated clothing, etc., analytical wastewater, or various wastewater such as various kinds of washing wastewater, the second chloride is used.
The coagulation sedimentation method in which iron is added and then neutralized is mainly employed.

[0004]

The above-mentioned coagulation and precipitation method by addition of an iron salt is an efficient method which has been practiced for a long time since a wide range of liquids can be used. However, neutralized iron hydroxide has poor filtration properties. As shown, the volume is large, and there are some difficulties in practical operation.

[0005] Further, uranium contained in iron hydroxide has a problem that it is difficult to carry out the subsequent treatment, it is necessary to store the uranium as it is, and the volume of waste increases.

[0006] The present invention addresses the above-mentioned situation, and by adding tannic acid and activated carbon to a waste liquid containing uranium and TRU, uranium and TRU in the liquid can be easily separated, and after separation, The purpose is to reduce the volume of waste.

[0007]

That is, the method for removing uranium and TRU of the present invention, which meets the above object, comprises adding tannic acid to an aqueous solution containing at least one element of uranium or TRU, And uranium or TRU are separated from the mother liquor by generating a compound of tannic acid and a compound such as uranium on activated carbon.

[0008]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a compound of uranium or TRU and tannic acid is prepared by adding tannic acid to a waste liquid containing uranium or the like. This uranium and T
Since the compound of RU and tannic acid is water-soluble, it cannot be separated from the mother liquor as it is, and therefore is adsorbed on activated carbon by post-treatment. Activated carbon is added and stirred, or an activated carbon column is preferably prepared and a waste liquid is preferably passed through the column. In any case, uranium or TRU which has become a compound with tannic acid by being adsorbed on activated carbon is converted from mother liquor. Separated and removed.

In this method of the present invention, the same effect can be obtained without using a conventional iron salt, a difficult step such as the conventional iron hydroxide filtration can be omitted, and separated uranium, Since the main components of TRU-containing waste are tannic acid and activated carbon, the volume of uranium and TRU-containing waste can be significantly reduced by reducing the volume by incineration.

(Experimental Example) An experiment was conducted based on Table 1 below. Note that the standard solution is a solution containing no impurities obtained by dissolving U ₃ O ₈ in nitric acid, and has a uranium content of about 10 ppm.
And the radiation dose is 6.872 × 10 ² Bq / cc. The analysis waste liquid is a predetermined analysis waste liquid which is once neutralized to pH 7 with NaOH or the like and filtered, and is a waste liquid containing miscellaneous impurities (radiation dose 4.890 × 1).
0 ² mm Bq / cc). Below margin

[0011]

[Table 1]

As is clear from the above results, it is found that by performing the adsorption treatment with activated carbon after adding tannic acid, the same uranium and TRU removal effect as the treatment by adding iron salt can be obtained.

[0013]

As described above, the uranium of the present invention,
A method for removing TRU is to add tannic acid to a waste liquid to generate a compound of tannic acid and the above-mentioned element such as uranium,
Thereafter, uranium or TRU is separated from the mother liquor by adsorbing the tannic acid and a compound such as uranium on activated carbon, and an equivalent removal effect can be obtained without using a conventional iron salt. Difficult processes such as conventional iron hydroxide filtration can be omitted, and the separated uranium- and TRU-containing waste is mainly composed of tannic acid and activated carbon. This has a remarkable effect of greatly reducing the amount of waste.

Claims (1)

[Claims] 1. An aqueous solution containing at least one element of uranium or TRU is added with tannic acid to form a compound of tannic acid and the above-mentioned element such as uranium. Uranium or TRU is separated from mother liquor by adsorbing uranium or TRU on activated carbon.