DD292891A5 - METHOD FOR SEPARATING STRONG FROM BARIUM SALTS - Google Patents

Abstract

The invention includes a process for the separation of strontium from barium salts. It relates to a process for the preparation of high-purity barium strontium compounds from high strontium-containing starting materials. The object is achieved by adding a strontium-containing barium chloride solution with a hydrogen peroxide solution and ammonia. From the resulting suspension, the present as a solid barium peroxide hydroperoxide is filtered off. This is then washed and dried to strontiumarmem barium peroxide or suspended in water and reacted with inorganic or organic acids with the recovery of hydrogen peroxide. The strontium-poor barium compounds obtained can be used in the fields of special ceramics, electronic and special optics. {Process; Separation; Barium salts, wholesome, strontium poor; Precipitation; Barium hydroperoxide; Starting material; Rueckgewinnung}

Description

field of use

The invention relates to a process for the preparation of strontium-poor barium compounds. The process can be advantageously used for the production of high-purity barium compounds from strontium-containing starting materials. Predominantly compounds such as barium peroxide, barium oxide, barium carbonate as well as barium chloride and barium nitrate are in strontium-poor quality important starting materials for new developments in the fields of special ceramics, electronics and special optics.

Characteristic of the known state of the art

It is already known to separate barium and strontium due to solubility differences of their particular salts in combinations with certain solvents.

Furthermore, processes for the separation of barium and strontium on the basis of extraction and ion exchange chromatography have been developed. These methods have gained importance for the analytical separation and determination of barium and strontium on a laboratory scale, but are not suitable for an industrial application. Variants of the barium-strontium separation for industrial use are described in the patents DE 1816891 and DE 2307253 and SU 1117284. A disadvantage of the mentioned methods is that they only allow the separation of small amounts of barium from strontium salt solutions.

Ef in processes for the purification of barium salts with low strontium content is presented in patent FR 2595089. It is characterized by the contact of an aqueous barium salt solution with an organic solvent containing at least one water-insoluble extractant such as carboxylic acid, phosphoric acid mono-ester or substituted quinoline-8-hydroxide. After phase separation, an aqueous barium salt solution reduced in the strontium content and an organic phase, which is particularly contaminated with strontium, are obtained.

Unfavorable is the use of organic compounds that are flammable and partially explosive and can form toxic decomposition products. The considerable amounts used and material flows of the solvent and extractant, the high number of extraction stages, the solvent and extractant losses and problems in pH stabilization and phase separation are further disadvantages of the method.

Object of the invention

The invention is based on the objective to separate strontium from barium with a few process steps and thus cost.

Essence of the invention

The invention is based on the object barium compounds with low strontium content of very strontiumhaltigen

Produce starting materials.

According to the invention the object is achieved in that a strontium-containing barium chloride solution is treated with a hydrogen peroxide solution.

This mixture is supplied at low temperatures continuously, with constant stirring, ammonia in the form of solution or gas. A suspension is obtained which contains barium peroxide hydroperoxide "BaO ₂ 2H ₂ O ₂ " as a solid, and the solid is separated on a separator from the filtrate and washed The barium peroxide hydroperoxide obtained is largely purified from strontium compounds containing separated strontium In the filtrate, this process removes up to 97 parts by weight in% of the strontium.

As starting solutions are technical barium chloride solutions in a concentration range of 10 (M00g / l BaCl ₂ 2H ₂ O and a strontium content up to 10 parts by weight in%, based on the barium used, can be used.

The use of barium chloride solution is of particular industrial importance, the use of other barium salt solutions, e.g. Barium nitrate solution is possible.

As hydrogen peroxide solution all commercially available qualities and concentrations are suitable.

In addition, solutions with very low concentrations can also be used. The addition takes place in almost stoichiometric amount to the barium used.

When dosing the ammonia, also in stoichiometric amount to the barium used, a temperature in the overall system below 30 ° C, preferably less than 20 ° C, to ensure. The reaction is associated with an increase in pH from pH 6.5 to pH 9.5.

As a reactor for the process agitator reactors and other introduced in the art reactor types are suitable, which allow an intensive mass transfer.

The strontium-poor barium peroxide hydroperoxide prepared by the proposed process can be further processed in many ways to form other barium compounds. Thus, by e'nfache drying of the filter wet barium peroxide hydroperoxide at temperatures of 373-573 K high purity barium obtained. From this barium peroxide, strontium-sparing barium oxide, which is suitable for the production of barium metal in getter purity, can be produced by customary processes.

On the other hand, the filtered and washed barium peroxide hydropcroxide can be suspended in water and processed with corresponding inorganic or organic acids, with simultaneous recovery of up to 80 parts by mass in% of the hydrogen peroxide used, to the respective bates salts in strontiumarmer quality. The recovered hydrogen peroxide is used again in the preparation of the barium peroxide hydroperoxide. Thus, the hydrogen peroxide used is recycled and only the losses are supplemented. A preferred variant is the reaction of suspended barium peroxide hydroperoxide with carbon dioxide to give very pure strontium-poor barium carbonate.

Embodiment 1

1750 g of BaCl ₂ · 2 H ₂ O are dissolved in 5 l of condensate. The resulting barium chloride solution contains 0.8 parts by weight in% strontium, based on the barium used. The solution is transferred to a 101 stirred reactor and mixed with 2,100 g of hydrogen peroxide solution containing 35 parts by mass in% hydrogen peroxide. The mixture is added with stirring for 30 minutes 1000 g of ammonia solution with 25 parts by weight in% ammonia. During the addition of the ammonia solution, the system is maintained at a temperature of 20 ° C by cooling. The pH increases during the reaction from pH 6.5 to pH 9.2.

The resulting suspension containing barium peroxide hydroperoxide, BaO ₂ .2H ₂ O ₂ as a solid, is separated on a filter.

The product obtained is washed free of chloride and dried at 12O ⁰ C. There are obtained 900 g of barium peroxide with a strontium content of 0.03 parts by weight in%.

Embodiment 2

2.5m ³ technical barium chloride solution concentration 351.5g / l BaCl ₂ 2H ₂ O and a strontium content of 4 parts by weight ir Strontium%, based on the barium used are mixed in an agitator reactor with 1050 kg of hydrogen peroxide solution with 35 parts by mass in% hydrogen peroxide , The mixture is added with stirring in about 30 minutes 500 kg of ammonia solution (25 parts by weight in%). During this time the system is kept at a temperature of 20 ° C by cooling. The pH increases during the reaction from pH 6 to pH 9. The resulting suspension is separated on a filter. The resulting barium peroxide hydroperoxide is washed free of chloride and dried at 120 ° C. There are obtained 460 g of barium peroxide with a strontium content of 0.28 parts by weight in%.

Embodiment 3

Analogously to the method explained in the exemplary embodiment 1, a barium peroxide hydroperoxide suspension is produced. The solid is separated on a filter and washed free of chloride with condensate of 20 ° C. The resulting filter cake with a water content of 35 parts by mass in% is suspended in 71 condensate and saturated in a stirred reactor with carbon dioxide at 25 ° C. The resulting barium carbonate is separated from the filtrate. There are obtained 71 filtrate with a hydrogen peroxide content of about 7 parts by weight in%. The filter-wet barium carbonate is dried at 12O ⁰ C. 1010 g of highly pure and very reactive barium carbonate are obtained with a content of brium carbonate of 99.9 mass% and a strontium content of 0.028 mass%.

Embodiment 4

In the hydrogen peroxide-containing filtrate, according to Embodiment 3, 1750 g BaCl ₂ 2 H ₂ O are dissolved with a strontium content of 0.8 parts by weight based on the barium used in%. The solution is supplemented with 730 g of hydrogen peroxide solution (35 parts by mass in%). The further procedure is analogous to embodiment 3.

Again, about 1000 g of high purity and reactive barium carbonate having a barium carbonate content of 99.9 wt% and a strontium content of less than 0.03 wt% is obtained.

Claims (6)

1. A process for the separation of strontium from barium salts, characterized in that from a strontium-containing barium salt solution by addition of hydrogen peroxide and ammonia at low temperatures stronitiumarmes barium peroxide hydroperoxide BaC> 2 · 2 H2O is precipitated. 2. The method according to claim 1, characterized in that the barium salt solution is preferably a strontium-containing barium chloride solution in the concentration range of 100-400 g / l BaCl ₂ · 2H ₂ O is used. 3. The method according to claim 1 and 2, characterized in that the strontium-containing filtrate separated barium peroxide hydroperoxide is washed and dried to very pure, strontium barium (dried strontium less than 0.03 parts by weight in% can be achieved). 4. The method according to claim 1 and 2, characterized in that the strontium-containing filtrate separated and washed barium peroxide hydroperoxide suspended in water and with inorganic or organic acids, with simultaneous recovery of up to 80 parts by weight in% of the hydrogen peroxide used, to the respective Barium salts are processed in strontiumarmer quality. 5. The method according to claim 1,2 and 4, characterized in that the separated and washed barium peroxide hydroperoxide, suspended in water, is saturated with carbon dioxide, so that after completion of the reaction by filtration, a barium-free hydrogen peroxide solution as a filtrate and a filter cake from which is obtained by simple drying a very strontiumarmes, pure and reactive barium carbonate pariumcarbonatgehalt of more than 99.9 parts by weight in%, strontium content less than 0.03 parts by mass in%). 6. The method according to claim 1,2,4 and 5, characterized in that the barium-free filtrate recovered hydrogen peroxide is used again for the production of strontiumarmem barium peroxide hydroperoxide. (Recycling).