Patent ID: 8912002

Claim:
A method of resin evaluation, comprising: (a) loading a known volume of water-washed divalent cation loaded resin with a known activity into a test column; (b) passing a solution with known concentration of univalent counter ion to be exchanged over the resin for an initial period of time; (c) repeating steps (a) and (b) for a different period of time than the initial period of time; (d) calculating the resin conversion X; (e) calculating a univalent counter ion tau value using the equations: t = τ Na ⁡ ( 1 - 3 ⁢ ( 1 - X ) 2 3 + 2 ⁢ ( 1 - X ) ) ( Eq . ⁢ 13 ) where ⁢ : ⁢ ⁢ τ Na = K d C Na = ρ Ca ⁢ R 2 6 ⁢ bD e ⁢ C Na ( Eq . ⁢ 14 ) where t is the time it takes to achieve a given resin conversion X, in minutes; ρ Ca is the molar density of divalent cation loaded resin in meq/mL; R is the resin particle radius; D e is the interparticle diffusion coefficient; and C Na is the concentration of univalent counter ion in the feed solution; (f) loading a known volume of water-washed univalent cation loaded resin with a known activity into a test column; (g) passing a solution with known concentration of divalent counter ion to be exchanged over the resin for an initial period of time; (h) repeating steps (f) and (g) for a different period of time than the initial period of time; (i) calculating the resin conversion X; (j) calculating a divalent counter ion tau value using the equations: t = τ Ca ⁡ ( 1 - 3 ⁢ ( 1 - X ) 2 3 + 2 ⁢ ( 1 - X ) ) where t is the time it takes to achieve a given resin conversion X, in minutes; ρ Na is the molar density of univalent cation loaded resin in meq/mL; R is the resin particle radius; D e is the interparticle diffusion coefficient; and C Ca is the concentration of divalent counter ion in the feed solution; and (k) calculating a ratio τ Na /τ Ca .