RADIOACTIVE WASTES
TREATMENT
Cleaning of radioactive liquids

UNIKET

Sorbent for the removal of cesium radionuclides from weak acidic and neutral liquids

Description
The sorbent UNIKET is a sorbent material based on microparticle Prussian Blue, iron-potassium hexacyanoferrate, КхFey[Fe(CN)6], where x = 0.2-0.8; y = 1.2-1.8. It is chemically fixed on cellulose carrier granules, with a content of sorbing substance not less than 10%.

The porous cellulose carrier in a sorbent composition provides greater access to sorption sites, which increases the capacity of the sorbent for cesium and improves the kinetics of sorption.

Potassium iron hexacyanoferrate can selectively remove cesium and thallium ions and other metals from aqueous solutions . The presence of sodium and potassium ions in solution does not reduce the capacity of the sorbent for cesium.

Standard characteristics

Modification of sorbent

ANFEZH

ANFEZH-K

Extracts

Cs

Cs

Salt concentrations

Up to 500 g/dm3

Up to 500 g/dm3

​Based on

​Iron Ferrocyanide

​Iron Ferrocyanide

​Inorganic

​Yes

​Yes

​Stable

​Yes

​Yes

Carrier

Cellulose

Aluminosilicate

Form

​Solide granules

​Solide granules

​Bulk density, kg/l

0.25-0.4

0.6

​Grain size, mm

0.1-1.0

0.1-1.0

Decontamination factor

1500-5000, up to millions

1500-5000, up to millions

​Capacity typically (BV)

​50 000 - 250 000

​50 000 - 250 000

​Capacity typically (l/kg)

100 000 - 400 000

100 000 - 400 000

​Operating pH area

2-8,5

2-8,5

​Max. operating temperature (°C)

80

80

Service flow rate typically (BV/h)​

​10-20

​10-20

Technical features

The effective usage is in a static mode (addition of the sorbent into the solution, followed by stirring and separation.

Recommended ratio is 0.5 - 1.0 kg of sorbent per 1000 liters (1m3) of solution. The contact time should be 1-1,5 hours if the initial activity of the cesium in the solution is not more than 5000 bBq/l. The extraction efficiency of the sorbent is >99%.

In the case that the activity contained in solution is higher than 5000 Bq/l, the contact time should be increased to 2 - 2.5 hours.

Under dynamic conditions, the rate of filtration of the solution through the sorbent UNIKET is recommended at speed of 3 - 6 m/h with thickiness of sorbent bed at least 30 cm. The optimum ratio of height to diameter of the sorbent layer column is 2.5 - 3.5.

For various technological tasks two modifications are available: UNIKET-2 (fine powder without carrier, 100% of sorption substance) and UNIKET-K (the carrier – aluminosilicate, opal).