CS236978B1 - A method of regenerating acidic solutions used in hydrochemical ore mining - Google Patents

Abstract

The purpose of the invention is to restore the leaching ability of solutions by separating soluble aluminum salts. At the same time, aluminum is obtained in the form of an industrially usable compound, aluminum oxide. The stated purpose is achieved by ion exchange of aluminum ions for hydroxonium ions H5O+ on an acidic cation exchanger. The sorption ability of the cation exchange is restored with a hydrochloric acid solution with a concentration of 35 to 45Ο kg.m”ý- Crystalline aluminum chloride is separated from the obtained eluate by concentration. Its thermal decomposition at a temperature of 100 to 300 °C produces aluminum oxide and gaseous hydrogen chloride, which is reused for the preparation of the elution solution. The invention can be used wherever metals are obtained by hydrochemical leaching with acidic solutions, while aluminum ions accumulate in these solutions.

Description

The invention relates to a process for the regeneration of acidic solutions used in hydrochemical ore mining. The solutions to be used for further leaching, whose leaching ability is mainly reduced by the content of soluble aluminum salts, are regenerated by exchanging aluminum ions for H 3 ^{O +} ions on an acidic cation exchanger. The elution of the aluminum ions from the cation exchanger is carried out with a hydrochloric acid solution. An aluminum chloride solution is obtained, from which a crystalline aluminum chloride AlGl6.6 H2O is formed by concentration. This is further subjected to thermal decomposition to form alumina.

- 2 236 978

Up to now, in the hydro-chemical extraction of metals, in particular uranium, with acidic solutions, these solutions have been treated after the leached metal has been separated by the addition of concentrated acid. Ballasts, especially aluminum salts, accumulate in the solutions. The overall salinity of the leaching solution increases, which adversely affects the leaching process, the leaching rate of the extracted metal decreases and there is a risk of perpendicular collapse of the leached rock by crystals of precipitated ballast salts. Also in the process of separation of the extracted metal, the increase in salinity of the leaching solutions is unfavorable. Sorption on ion exchangers decreases sorption rate and capacity to which they can be saturated with the extracted metal.

These disadvantages are substantially reduced by the method of regeneration of acidic solutions used in the hydrochemical ore mining, in particular of the acidic sorption wastes in uranium mining, intended for further use in the leaching process, the leaching ability being reduced mainly by the aluminum salt content. these solutions are renewed by ion exchange mainly of aluminum ions for hydroxides of H 2 O ⁺ on an acidic cation exchanger, where the aluminum ions are sorbed and then eluted with the hydrochloric acid solution, while the sorption capacity of the acidic cation exchanger is restored and aluminum chloride solution is obtained. The crystalline aluminum chloride AlCl 3 · 6 · H 6 O is then concentrated by concentration, which is further subjected to thermal decomposition to form alumina and hydrogen chloride gas, which is reused to prepare the elution solution.

By discharging aluminum ions from the leaching solution, its salinity is reduced, thereby increasing its leaching ability and improving the separation process of the extracted metal from the solution.

- 3 236

The process according to the invention also makes it possible to achieve a more complex use of the ores treated by the hydrochemical process without the need for further leaching chemicals) and to obtain economically advantageously a significant amount of aluminum in the form of an industrially usable compound.

An example of a possible method of a particular embodiment is given below.

The invention can be used wherever metals are obtained by a hydro-chemical process by leaching with acidic solutions, where aluminum ions accumulate in these solutions.

Example

236 978

Aluminum ions are separated from the leach solution after the separation of uranium containing 4.5 kg / m &^lt; 3 ^> aluminum by sorption on an acid cation exchanger of the sulfonated styrene divinylbenzene type in exchange for hydroxyl ions H ^< ^{+ &gt}; The content of aluminum ions in the regenerated leaching solution drops to 0.5 kg.m and the free sulfuric acid content is increased by 22 kg.nf *. The cation exchanger is saturated with aluminum ions to 12 kg.nf ^ and the potoin is eluted with a hydrochloric acid solution. with a concentration of 420 kg.r-3 HCl, the aluminum ion content of the cation exchanger being reduced to 1 / kg.nT ^. the aluminum chloride solution at a concentration of 19 kg · m @ -1 Al obtained after evaporation of the excess water precipitated crystalline aluminum chloride AlCly6 HgO in an amount of 92 kg / m @ 2 of cation exchanger. Thermal decomposition at 150 ° C yielded 21.6 kg of hydrated alumina from this amount of crystals. The HCl-containing gas phase was cooled and absorbed in water to give hydrochloric acid, which was reused to prepare the elution solution.

Claims (4)

Object of the invention 236 978 1 »A method for the regeneration of acidic solutions used in the hydrochemical ore mining, in particular of the acidic sorption wastes in the uranium mining, intended for further use in the leaching process, their leaching ability being reduced mainly by the aluminum salt content. mainly by the exchange of aluminum ions for hydroxyl ions H ^O ⁺ on an acidic cation exchanger, in which the aluminum ions are absorbed and then eluted with a hydrochloric acid solution, while the sorption capacity of the acidic cation exchanger is restored, and an aluminum chloride solution is obtained. Concentration eliminates crystalline aluminum chloride AlCly6 HgO, which is further subjected to thermal decomposition to form alumina and hydrogen chloride gas, which is reused to prepare the elution solution. 2nd Method of according to Claim 1 _f} wherein the hydrochloric acid concentration in the eluting solution is in the range 35 to 450 kgm "^. 3. The method of item 1; characterized in that the thermal decomposition of the crystalline aluminum chloride is carried out in a temperature range of 100 to 300 ° C. 4. The process of claim 1, wherein the waste heat obtained by cooling the thermal decomposition products of the crystalline aluminum chloride is used to heat the hydrochemical extraction solutions.