A pilot plant for the removal of cationic fission products from milk: II. Efficiency of the process and composition of the product

Abstract

AS previously described, the process consists essentially of the passage of milk at pH 5-2-5-25 through an ion exchange resin charged with a suitable mixture of the ions of Ca, K, Na and Mg.When citric acid was used for reduction of the pH and 30 resin bed volumes (r.b.v.) were treated, the concentration of residual 85 Sr was reduced to 2-4 % whether it had been introduced in vivo or in vitro. There was no evidence that repeated use of the resin bed resulted in diminished radiochemical efficiency.About the same efficiency of removal of 133 Ba was obtained but this efficiency was achieved with 137 Cs only if not more than 15 r.b.v. were treated. If 30 r.b.v. were treated the concentration of residual 137 Cs was as much as 30%.When hydrochloric acid was substituted for citric acid the residual concentration of 85 Srwas 1 1 % .Analyses of milks processed after adjustment of pH with either citric or hydrochloric acid showed the products to be satisfactory. The only important constituent lost was thiamine. Concentrations of heavy metals remained well below maximum values. Although the flavour of milk was detectably changed by the treatment it was still acceptable.The results are discussed in relation to the problem of achieving maximum decontamination and to the design of a large scale plant.

A pilot plant for the removal of cationic fission products from milk: I. Design and construction

“…The repeated washing and regeneration of the resin has produced no detectable physical deterioration and losses due to washing out of fine particles have been negligible. As is reported elsewhere (Glascock & Bryant, 1968) there was also no deterioration in radiochemical efficiency.…”

“…The regenerating solution used to remove radiostrontium from the resin and to charge it with the required mixture of ions is of the composition recommended by Edmondson et al (1962) and contains per litre: calcium chloride (dihydrate), 53-5 g; potassium chloride, 23-1 g; sodium chloride, 8-5 g and magnesium chloride (hexahydrate), 15-1 g. The chemicals are of the cheapest available commercial grade. The suitability of this grade has been examined and is reported on by Glascock & Bryant (1968).…”

“…Thus, when the plant is in continual use the solution in tank 4 has been used 3 times, that in tank 3 twice and that in tank 2 once. The efficiency of the procedure for the removal of radiostrontium from the column has been investigated and is reported on by Glascock & Bryant (1968).…”

The Removal and/or Reduction of Radionuclides in the Food Chain

“…The two-resin bed system described previously (16) for Cs removal reduced 85Sr introduced in vitro or in vivo in milk to 2% to 4% of the original value. A pulsed-bed ion exchange contactor was designed for continuous operation, and the improvements concerned the regenerating solution for simultaneous regeneration and sanitization (38).…”