Extraction of Uranium from Phosphoric Acid plants

[Apoorva Sampat_11CHE1073]

The high capital and operating costs of the existing technology with respect to the uranium market contribute to the continued absence of commercial uranium recovery facilities in phosphoric acid plants. 

Here is an innovation in uranium extraction by BARC, which has been tested on a laboratory & pilot scale and might soon be employed on a commercial scale.

[Vishwanath Dalvi]

Please describe the innovation!

[Apoorva Sampat_11CHE1073]

The distinctive features of this innovative process are:

a) Extraction of uranium from fertilizer-grade phosphoric acid with a novel synergistic mixture of di-nonyl phenyl phosphoric acid (DNPPA) and tri-n-butyl phosphate (TBP).

Such a system enables reductive stripping, adoption of dual cycle approach which yields high purity uranium, leads to minimum contamination of phosphoric acid as is desired by host fertilizer plant, avoids corrosive chemicals and has the flexibility of being integrated into a host plant, handling both weak and concentrated phosphoric acids.

b) Uranium extracted by DNPPA-TBP is further subjected to a second cycle of extraction using D2EHPA (Di-(2-ethylhexyl)phosphoric acid)-TBP and scrubbing impurities. The uranium is finally converted to a high purity UO3 product using precipitation with hydrogen peroxide and heat treatment at 200 °C.

 

The peroxide precipitation yields a ‘yellow cake’ which is far superior to the Magnesium Diuranate (MDU) industrially produced for decades in the country.

[Alec Desai]

Uranium can be extracted from wet process phosphoric acid-

1. octyl pyrophosphoric acid (OPPA) in kerosene,

2. a mixture of tri-N-octyl phosphine oxide and di-2-ethyl-hexyl phosphoric acid,

3. above no.2 combined with octyl-phenyl phosphoric acid,

The energy value of the uranium extracted which is then converted to yellow cake is ten times more than the energy required to produce it. So this makes phosphate industry net producer of energy.