US 5,512,256 A · Method of separation of yttrium-90 from strontium-90

Abstract

A method for purifying Y-90 from a Sr-90/Y-90 "cow" wherein raw Sr-90/Y-90 source containing impurities is obtained from nuclear material reprocessing. Raw Sr-90/Y-90 source is purified to a fresh Sr-90/Y-90 source "cow" by removing impurities by addition of sodium hydroxide and by removing Cs-137 by further addition of sodium carbonate. The "cow" is set aside to allow ingrowth. An HDEHP organic extractant is obtained from a commercial supplier and further purified by saturation with Cu(II), precipitation with acetone, and washing with nitric acid. The "cow" is then dissolved in nitric acid and the purified HDEHP is washed with nitric acid and scrubbed with either nitric or hydrochloric acid. The dissolved "cow" and scrubbed HDEHP are combined in an organic extraction, separating Y-90 from Sr-90, resulting in a Sr-90/Y-90 concentration ratio of not more than 10(E-7), and a metal impurity concentration of not more than 10 ppm per curie of Y-90. The separated Y-90 may then be prepared for delivery.

Claims10

Dependent claims

A method for purifying Y-90, comprising steps of:

(a) purifying a raw Sr-90/Y-90 source to a fresh Sr-90 source "cow" and permitting Y-90 ingrowth by removing at least a first group of impurities including iron, calcium, magnesium, sodium, chromium, and cerium by precipitating said impurities with sodium hydroxide wherein the sodium hydroxide contains little or no carbonate, and further purifying said "cow" by adding sodium carbonate for precipitating Sr-90 and leaving Cs-137 in solution,
(b) purifying a HDEHP organic extractant to remove traces of metal impurities,
(c) pretreating of said "cow" to a separation ready Sr-90/Y-90 source,
(d) pretreating purified organic extractant to a separation ready organic extractant, and
(e) separating Y-90 from Sr-90 by mixing said separation ready Sr-90/Y-90 source with said separation ready organic extractant obtaining a Y-90 product that has a Sr-90/Y-90 concentration ratio of not more than 10(E-7), and a metal impurity concentration not more than 10 ppm per curie of Y-90.

2 more elements

A method for purifying Y-90, comprising steps of:

(a) procuring high purity nitric acid and hexane, reagents,
(b) purifying a raw Sr-90/Y-90 source to a fresh Sr-90 source "cow" having at least 99.99 (weight or mole) percent chemical and radiochemical purity,
(c) allowing a grow-in time for the purified fresh Sr-90 source to decay into a source mixture of Sr-90 and Y-90,
(d) purifying an organic extractant with Cu(II) and acetone,
(e) mixing a high purity dilute nitric acid reagent with the "cow" for pretreating said "cow" to a separation ready Sr-90/Y-90 sources,
(f) pre-treating said purified organic extractant of step (d) reagent with a high purity nitric acid reagent washing, to a separation ready organic extractant,
(g) combining the pre-treated mixture of step (e) with the separation ready organic extractant of step (f) for solvent extraction of Y-90 into an organic phase,
(h) scrubbing the organic phase of step (g) with an amount of dilute high purity nitric acid reagent for further removal of trace amounts of Sr-90,
(i) stripping Y-90 from the scrubbed organic phase of step (h) with a concentrated high purity acid reagent solution,
(j) removing traces of the organic phase from the stripped Y-90 of step (i) with hexane,
(k) boiling the result of step (j), and obtaining a first dry product of Y-90 having a Sr-90/Y-90 concentration ratio of not more than 10(E-7), and a metal impurity concentration of not more than 10 ppm per curie of Y-90,
(l) dissolving the first dry product in concentrated hydrochloric acid,
(m) removing trace metals from the dissolved first dry product through ion exchange,
(n) heating the dissolved first dry product of step (m) making, a second dry product and
(o) dissolving the second dry product in dilute hydrochloric acid.

12 more elements

Dependencies are inferred from the claim text.

Method of separation of yttrium-90 from strontium-90

Life of this patent

Method of separation of yttrium-90 from strontium-90

Life of this patent

Abstract

Claims10