CS198693B1 - Method of radium separation from waters - Google Patents

Description

(54)

Method of separation of radium from water

The invention relates to a process for separating radium from water.

When separating radium from uranium mine wastewater, it is necessary to reduce the radium concentration to a maximum radium concentration of 3 pg Rá / l. Up to now, ion exchangers produced by us and / or biosorbents have been tested and applied on a commercial or pilot scale in addition to conventional ion exchanger imports.

Using our ion exchanger, the elution of radium from the transducer is performed either with sodium chloride or calcium chloride. The presence of a high concentration of these salts in the eluate then adversely affects the longer separation of the radium from the eluate by precipitation (especially from calcium chloride eluates) and the possibility of regenerating the leaching solutions. When biosorbents are applied, this method requires activation with manganese dioxide, which results in leakage of manganese into the water, the concentration of which is then greater than the concentration limited by the applicable standard. In addition, the capacity of the biosorbents is greatly reduced by easy washing of the active ingredients.

From a technical point of view, the above-mentioned facts require the use of additional technological operations that prolong the cycle of radio separation.

The above mentioned drawbacks are eliminated by the method of separation of radium from water according to the invention. It is based on the fact that the aqueous solution is treated with a polymeric sorbent of the polyester type, consisting of diols having a carbon number of 2 to 16, preferably ethylene glycol or diethylene glycol 188 693 and dicarbonate. aromatic, aliphatic and aromatoaliphatic acids having a carbon number of 1 to 12, preferably teraphthalic acid, isophthalic acid and adipic acid, or modifications thereof with aromatic and aliphatic bonded carboxylic, sulfonic and phosphonic groups or metal oxides, for example titanium dioxide, alumina and zirconia.

The effect of the process is to allow the separation of radium at a concentration of the order of 10 µg Ra / l and lower to 1 µg Ra / l, the sorbent concentration being selected according to the concentration of sorbed radium and the concentration of alkaline earth in water.

By using this method, economical savings are achieved by using a simple device, at a very low sorbent price that is 2 to 5 times lower than that of conventional ion exchangers, simply further processing the sorbent with sorbed radium, and for regenerating the sorbent for use in subsequent cycles. Because of the low cost of the sorbent, a high-concentration concentrate can be obtained by burning the sorbent without further regeneration.

The following examples illustrate the invention.

Example 1

Separation was used for separation of radium from water, where at a concentration of radium in water equal to 60 ng Ra / l, a phase ratio of 100 ml per 0.5 g of sorbent of terephthalic acid-ethylene glycol copolymer, the adsorption under static conditions was 97% after 1 hour contact. while the sorption of the styrene-divinylbenzene copolymer with SO4H groups at the same initial radium concentration and the same contact time and higher content of the transducer (100 ml per g transducer) is only 87%. '

Example 2

In the separation of radium from waters with a concentration of Ra equal to 60 ng Ra (1 in the presence of 0,2 mg / l MW, 0,6 mg Pe / l, 2,0 mg K / l, 14 mg Mg / l and 10 mg Sr / 1, at a phase ratio of 100 ml per 0.5 g of sorbent under static conditions after 1 hour contact, radium was sorbed to 96% on the sorbent of a copolymer of 2-methyl, 1,4-benzenedicarboxylic acid and ethylene glycol containing 25 mol% of the alkali acid salt sulfoisophthalic *

Example 3

Sorption of radium with a sorbent of sulfoisophthalic and adlpic acid with diethylene glycol containing 20 mol% -SO4H results in the sorption of radium with an initial concentration of 0.1 / µg Ra / l at a phase ratio of 100 ml per g of sorbent of 96% ·

Example 4

At a radium concentration of less than 10 µg / g of Ra / 1 phase ratio of 100 ml / 0.5 g of terephthalic acid polyester sorbent, 5% adipic acid mol and 1,4-butyldiol containing 18.2% sodium salt, contact time is 1 hour sorption is practically 100%,

Example 5

Concentrated radium-containing eluate using 0.5 M nitric or hydrochloric acid as the elution solution was virtually free of iron, aluminum and alkali3

198 893 l, since these do not adsorb during the sorption of radium, as shown in Table 1. This makes it possible to obtain a radium concentrate with a negligible content of these impurities even at a high content of these components in water.

Table 1

Sorption of some metals by sorbent of terephthalic acid-ethylene glycol copolymers from aqueous solutions of P _water : P ₀ = 10: 1 (ml / g)

metal ^c Me % sorption Al 5.4 g / l 0.5 Pe 2 g / l 0.2 On 40 g / l 0.1

Example 6

In the separation of radium from water with a concentration of Ra equal to 0,6 µg Ra / l at a phase ratio of 100 ml per 0,5 sorbent containing a copolymer of 1-butyl, 2,4-benzenedicarboxylic acid and ethylene glycol modified with 4% T10 ₂ At the time of contact, radium was sorbed to 96.5%. Example 7

The separation of the radium at a concentration of 0.3 µg / l, a phase ratio of 100 ml per 0.1 g of sulfo-phthalic acid adipic sorbent with diethylene glycol containing 1% phosphonic acid groups, was practically 100% sorption.

The method of separation of radium from water by sorption can be used on both operational and laboratory scale, where it is necessary to obtain waters without the presence of radium and where it is necessary to obtain enriched radium concentrate, for example in purification stations of uranium ore mining areas, water management, processing radioactive waste or even in the separation of radium from mixtures applied in medicine and other non-chemical areas.

Claims (1)

SUBJECT OF THE INVENTION A method of separating radium from water, characterized in that the aqueous solution is treated with a polymeric sorbent of a polyester type consisting of diols having a carbon number of 2 to 16, preferably ethylene glycol or diethylene glycol with dicarbonated aromatic, aliphatic and aromatoaliphatic acids of 1 to 12 , preferably terephthalic acid, isophthalic acid and adipic acid, or modifications thereof with aromatic and aliphatic bonded carboxylic, sulfonic and phosphonic groups or metal oxides, for example titanium dioxide, alumina and zirconium dioxide.