DD294287A5 - METHOD FOR FINE CLEANING WAITRING LITHIUM SALT SOLUTIONS OF ERDALCALIIONS BY ION EXCHANGERS WITH COMPLEX ANODISING GROUPS - Google Patents

Abstract

The invention relates to a process for the fine purification of lithium salt solutions. In this case, interfering impurities, in particular alkaline earth ions, are removed with the aid of ion exchange resins containing complex-forming anchor groups such as CH.sub.2N (CH.sub.2COOH) .sub.2 or CH.sub.2N CH.sub.2P (OH) .sub.2, with little expenditure of time and with an effective cost-benefit ratio, and very pure lithium salts are obtained. It is expedient to use the exchanger in the lithium form and to operate at elevated temperature, preferably in the range of 30-50 ° C. The regeneration of the exchangers is carried out by elution with dilute hydrochloric acid and subsequent loading with Lithiumhydroxidloesung {ion exchanger with complex-forming anchor groups; Fine cleaning of lithium salt solution; Erdalkaliionenabtrennung; usable volume capacity; regeneration; increased operating temperature; iminodiacetic; aminophosphoric}

Description

Field of application of the invention

The invention relates to the field of chemistry and hydrometallurgy. It relates to a process for the fine purification of aqueous lithium salt solutions of alkaline earth metal ions. Particularly useful is their use in the context of the workup of lithium-containing mineralized drilling or associated waters as they occur, for example, in natural gas production.

Characteristic of the known technical solutions

For the separation of alkaline earth compounds from lithium salt solutions, a number of different methods is known. Thus, a pure product is obtained according to BRC-PS 2157684 over several precipitation and evaporation stages. The disadvantage in this case, on the one hand, is the use of labor-time and labor-intensive filtration operations. On the other hand, this process is very energy-consuming by the evaporation. Also proposed in SU-PS 93 5478 method of purification by selective carbonate precipitation has next to the disadvantages mentioned above yet another. It consists in the fact that an additional reaction step, the dissolution of the separated lithium carbonate in acid, is required.

Object of the invention

The aim of the invention is to obtain high-purity lithium salt solutions with little effort on working time and energy and thus to make the fine cleaning process more economical.

Explanation of the essence of the invention

The invention has for its object to provide a method for fine cleaning of lithium salt solutions, which operates inexpensively and the separation of alkaline earth ions below the detection limit technologically and economically low permits. According to the invention the object is achieved in that the alkaline earth-containing lithium salt solutions are passed through ion exchangers with complex-forming anchor groups. Particularly suitable anchor groups for the separation of the alkaline earth metal ions are iminodiacetic acid and amino phosphonic acid groups.

With appropriate filling of these ion exchange resins in columns, special attention must be paid to the ratio of column diameter to bed height and, for this purpose, to set the optimum flow rate of the lithium salt solution to be purified.

A convenient usable volume capacity can be achieved by converting the complexing ion exchanger to the Lr form. An operating temperature of the ion exchanger between 30-50 ⁰ C. In comparison with cation exchange resins as described in the literature is appropriate here (J. prakt Chem.29 [1965] 65;... Anal Chim Acta 34 [1966] 71) to were used for analytical purposes for the separation of alkali and alkaline earth metal ions, the complex-forming ion exchangers are characterized by significantly higher usable volume capacities.

A regeneration of the exchangers after exhaustion can be carried out with 0.1 or 1 M HCl.

Ausführungsboispiol

example 1

An aqueous salt solution (Li ⁺ 7 g / l, Ca ² * 880 mg / l, Mg ^{J +} 43 mg / l) is added at 30 ° C operating temperature through the ion exchanger MC 50 in the Lr form. The usable volume capacity is 52g / l.

After egg schöpfüng regeneration with 1M HCI. Subsequently, the ion exchanger with LiOH solution is converted back into the Li + form and is again operational.

Claims (2)

1. A process for the fine purification of lithium salt solutions, characterized in that at elevated temperature, in particular in the range of 30 ⁰ C to 50 ⁰ C, an ion exchange process of exchange resins, the complex-forming anchor group such as preferably -CH ₂ -N (CH ₂ COOHh or - CH ₂ -N [CH ₂ -P (OH) ₂ J ₂ contained, using the exchanger in the lithium form is used. 2. The method according to claim 1, characterized in that the regeneration of the ion exchanger by elution with dilute acids, preferably with dilute hydrochloric acid and subsequent loading with lithium hydroxide solution.