SU140051A1 - Purification method rubidi chloride - Google Patents

Description

A known method of purifying rubidium chloride from impurities, such as potassium, consists in converting technical rubidi chloride in an aqueous solution to rubidium bromide at elevated temperature, cooling the solution, filtering and calcining the precipitate. This method reduces the potassium content only to 0.03-0, 04% and has a number of disadvantages (duration of the process, the absence of a scheme for the regeneration of bromine, iodine and waste containing up to 60-70% rubidium chloride).

The proposed rubidium chloride purification method is characterized in that the technical rubidium chloride is converted twice at 90 ° to rubidium bromohydride first in an aqueous solution, then in a 0.5 M solution of acetic acid, with intermediate calcination at 400 ° filtered rubidi bromide.

The method of purification of rubidium chloride containing 2-5% potassium chloride is carried out according to the following procedure.

Bromine is added to carefully rubbed iodine with a 3% excess over the stoichiometric portions with stirring.

A concentrated solution of rubidium chloride heated to 90 ° is added to the liquid iodine bromide obtained. The mixture is stirred at 90 ° until the iodine bromide is completely dissolved. Then, without stopping stirring, the reactor is cooled to O.

Precipitated orange crystals of rubidium bromoiodchloride (ClBr). The NZO is filtered off, washed with ice water and dried in air.

The isolation of rubidium chloride is performed by calcining the resulting rubidium bromohydride at 350-400 °.

For every 1 kg of technical rubidium chloride containing 2-5% potassium chloride, requires .; for the first precipitation 1.05 kg iodine and 0.66 kg (ill ml) of bromine.

jYo 140051-2 The rubidi chloride thus obtained contains 20-30 times less potassium.

After the first purification, rubidium chloride is subjected to secondary purification in a similar way, but not using an aqueous solution, but from 0.2-1, an OM solution of acetic acid, the final product contains about 0.0002-0.0003% of calcium, sodium, lithium and traces calcium.

To remove rubidium bromide, which is almost always contained in the amount of 3.0-3.5% rubidium chloride, the chloride is dissolved when heated in water and chlorine or chlorine-air mixture is passed through the resulting solution until the reddish brown color turns to light yellow. .

To reduce the cost of purification of rubidium chloride, it is envisaged to trap iodine bromide, separating it during calcination, by absorbing it with a concentrated aqueous solution of rubidi chloride by the reaction + H20 - Rb3 (CIBr) .H2O. The resulting bromodiochloride is returned to the precipitation operation.

The mother liquors remaining after precipitation of bromide chloride are also returned to the process until the calcium chloride content at the first operation reaches 5-10%, and at the second 0.2-0.5%; in this case, they are taken out of the cycle, evaporated, the precipitate P1 is molten and, as a mixture, rubidi and potassium chlorides are returned to one of the penultimate stages of the ferrocyanide extraction of rubidi chloride from spent magnesium electrolyte. Thus, rubidium losses are minimized.

If necessary, iodine extraction can be provided by the process scheme.

. Subject invention

The method of purification of rubidium chloride from impurities, such as potassium, by transferring technical rubidi chloride in an aqueous solution to rubidium bromohydride at elevated temperature, cooling the solution, filtering and burning the precipitate, characterized in t at 90 ° in rubidium bromiodiochloride, first in an aqueous solution, then in a 0.5 M solution of acetic acid, with intermediate calcination of the filtered rubidi bromoiodchloride at 400 °.