Abstract: A two-cycle countercurrent extraction process for recovery of highly pure uranium from fertilizer grade weak phosphoric acid. The proposed process uses selective extraction using di-(2-ethyl hexyl) phosphoric acid (D2EHPA) and tri-n-butyl phosphate (TBP) with refined kerosene as synergistic extractant system on hydrogen peroxide treated phosphoric acid, and stripping the loaded extract with strong phosphoric acid containing metallic iron to lower redox potential. The loaded-stripped acid is diluted with water back to weak phosphoric acid state and its redox potential raised by adding hydrogen peroxide and re-extracted with same extractant system. This extract is first scrubbed with sulfuric acid and then stripped with alkali carbonate separating iron as a precipitate, treated with sodium hydroxide precipitating sodium uranate, which is re-dissolved in sulfuric acid and converted with hydrogen peroxide to highly pure yellow cake of uranium peroxide.
Type:
Grant
Filed:
March 31, 2002
Date of Patent:
March 20, 2007
Assignee:
Secretary, Department of Atomic Energy, Government of India
Abstract: The invention relates to a pocket type digital radiation dosemeter comprising of a detector, which converts the ionisation in the detector caused by the incidence of ionising radiation of certain energy range into electrical impulses, a low power pulse amplifier, that amplifies the electrical pulses from the detector to detectable amplitudes, a discriminator circuit, that is used to reject pulses of origin other than those caused by the ionising radiation, a programmable divider circuit for calibrating the dosemeter, an electronic counting circuit and a six digit LCD display. The sensitivity of the dosemeter is 1 count per ?Sv (micro Sievert) and the accuracy is within ±15% from 60 keV to 1.25 Mev of X or Gamma radiation. A metallic energy compensation filter and a discriminator threshold modulation circuit are used to provide uniform response within ±15% from 60 KeV to 1.25 MeV.
Type:
Grant
Filed:
September 7, 2001
Date of Patent:
March 7, 2006
Assignee:
Department of Atomic Energy, Government of India
Abstract: A novel and inexpensive excitation circuit based on a single switch and a single source drives helium-free TEA CO2 lasers, mini to conventional types, providing low divergent output. By varying the partial pressure of either CO2 or N2, the duration (FWHM) and the peak power of the laser pulse (for a system with active volume about 70 cc) is made to vary by a factor of about 7 and about 5 respectively. The fact that expensive and scarce helium is not a constituent of the laser gas mixture makes it an ideal system for high repetition rate operation as the gas re-circulatory loop consisting of the heat exchanger and the catalytic re-converter, a mandatory requirement for conventional systems to recycle helium gas, can be readily dispensed with here. This laser can be used wherever a TEA CO2 laser with conventional gas mixture containing helium is used.
Type:
Grant
Filed:
July 3, 2003
Date of Patent:
September 27, 2005
Assignee:
Secretary, Department of Atomic Energy Goverment of India
Inventors:
Dhruba J. Biswas, Jonnaiagadda Padma Nilaya, Aniruddha Kumar
Abstract: An improved process of extraction of uranium from phosphoric acid and in particular uranium VI from phosphoric acid especially strong phosphoric acid using a selective synergistic extractant mix of an organo-phosphorous acid and a neutral extraction agent. The process basically involves the steps of extraction comprising contacting said acid with a selective synergistic extractant system of di-nonyl phenyl phosphoric acid (DNPPA) and a neutral agent selected from di-butyl butyl phosphonate (DBBP) and tri-n-octyl phosphine oxide (TOPO); and recovering the uranium values from the loaded organic phase. The above process would provide for an improved process for recovery of uranium both from weak and strong phosphoric acids using a stable and relatively cheap extractant system. The process is directed to improved recovery of U-VI from phosphoric acid by way of a simple, industrially applicable and cost-effective process.
Type:
Grant
Filed:
September 7, 2001
Date of Patent:
November 11, 2003
Assignee:
Secretary, Department of Atomic Energy, Government of
India