Pregnant liquor

The liquor from the first reaction is used as a pregnant liquor to be fed to electrowinning cells. An important electrical current benefit is realized in that it is only necessary to convert cuprous copper (Cu+) to copper rather than the conventional electrowinning process where cupric copper ( - ) is converted to copper. In an alternative process developed by Cymet (6), the cuprous chloride is crystallized from this liquor by cooling. The cuprous chloride is later reduced to copper in a furnace using hydrogen. 

Buildup of any solute in the wash liquor based on specified fractions, p and q, recycled from pregnant liquor and residue liquor, respectively (optional). 

Eq. 15 is subsequently solved for AN. Similar rela-r tionships are derived for the pregnant liquor treatment steps. 

The computer program is compact. For a particular application it had only 500 FORTRAN statements including subroutines for seven rate equations and equilibrium relationships, as well as seven pregnant liquor treatment steps. For a series of semibatch reactors, the program calculates the gradual concentration changes of all streams per pass based on initial conditions. 

Stage 8 column (c) on stand-by to become column (b) in next cycle PL = pregnant liquor W = water 1 = 1st eluant 2 = 2nd eluant P = to precipitation BD = barren discharge (Reproduced by permission from Ion Exchange In Uranium Extraction , in Ion Exchange Sorption Processes In Hydrometallurgy , Critical Reports on Applied Chemistry, Vol. 19, ed. M. Streat and D. Naden, Wiley, Chichester, 1987, Ch. 1)... 

Pregnant liquor Loaded organic Advanced electrolyte... 

A forward displacement wash is given to column 1 at 60 gal/min using one bed volume of 0 1N sulphuric acid. This displaces the residual pregnant liquor to columns 2 and 3. 

In the past, the recovery of uranium from the pregnant liquor solution usually involved precipitation as uranium oxide (UjOg) concentrates (UOC). But as the quality of UOC obtained by precipitation from acid leach is not very good ion exchange and solvent extraction are used in most plants nowadays. Precipitation from carbonate leaching produces a reasonably pure uranium concentrate. A detailed description of these processes and the operational and the economic considerations is beyond the scope of this book and can be found elsewhere (Grenthe 2006). 

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