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INVENTION
Russian Federation Patent RU2009228

Method of extracting metals from aqueous solutions

Method of extracting metals from aqueous solutions

Name of the inventor: Balanovsky Nikolay Vladimirovich; Zelenchev Alexander; Sokal Ludmila; Tatarnikov Alexey Viktorovich
The name of the patentee: Nikolai Vladimirovich Balanovsky; Zelenchev Alexander; Sokal Ludmila; Tatarnikov Alexey Viktorovich
Address for correspondence:
Starting date of the patent: 1992.05.29

Usage: hydrometallurgy ferrous, rare earth and precious metals, in particular their removal from extraction of aqueous solutions of various amines and quaternary ammonium salts. SUMMARY: the extraction of metals from aqueous solutions by extraction is carried out with solutions of amines and / or quaternary ammonium bases, two organic radicals each of which represent a 2,4-dietiloktily.

DESCRIPTION OF THE INVENTION

The invention relates to hydrometallurgy ferrous, rare earth and precious metals, in particular, to their extraction of aqueous solutions of various amines and quaternary ammonium salts (CHAO).

Fundamental work on the extraction of metals by secondary, tertiary amines and salts PJSC were carried out in the fifties and sixties. At the same time were the basic laws of the structure of the amines influence on their extractive capacity and the compatibility of the salts obtained with organic diluents.

It has been shown that increasing the degree of branching of the aliphatic radicals of amino prevents extraction of metals, but improves the compatibility of the amine salt with a diluent. Thus, if metal complexes with straight-chain amines are stable only in a strongly polar diluents or inert diluents (to 0.2-0.3 M) with additives as modifiers of higher alcohols, tributyl phosphate (TBP) and m. P., That such industrial salt amines as triizoalkil (C 7 -C 9) amine resistant to low-polar aromatic diluents. Highly branched amine salts such as amine-9D 178 - dodetseniltrialkilmetilamin, di (tridecyl) amine, tri (tridecyl) -amine, NBHA-N-benzyl-1 (3-ethylpentyl) -4-etiloktilamin, S-amine 24 bis (1-isobutyl-3,5-dimethyl) amine, at a concentration of 0.1 M / l of organic solution are stable in the pure inert diluent, such as kerosene. (Coleman et al. Report on the Second International Conference on Peaceful Uses of Atomic Energy (Geneva 1958) in the book. "The technology of nuclear materials" Atomizdat M., 1959, p. 352).

The solutions of amines in polar diluents used for analytical purposes, the use of metals in the same technology they do not find because of toxicity and the high cost of diluents. The introduction of modifiers to the amine system - inert diluent leads to complication, and often to the deterioration of metals extraction and distribution coefficients ( ) Elements such as U, Zn, Fe, Mo falls in dozens of times. The consequence of low concentrations of amine in an inert diluent (0.1 M) is a little different extractants for metals capacity (for example, by extraction from hydrochloric media - 6 g / l Fe; 8 g / l Ga; 3 g / l Zn; 6 g / Cd l, 3 g / l Co; 3 g / l Cu), which leads to their use in the processing of only the poor valuable component solutions become very large because the extraction member from its concentrated solutions of the organic phase flows.

Guidelines for the use of salt solutions in an inert diluent CHAO concentration above 0.05M without introducing modifiers for extraction of metals in contact literature found. In the industry, they are used only in admixture with higher alcohols or TBP, for example, Pt or Cu extraction.

Thus, the solubility limit of salts of amines, in an inert diluent is a major constraint of amine extraction techniques noble non-ferrous, rare and rare earth elements.

To some extent, overcome this obstacle in the closest to the proposed invention the method of separation and extraction of Co, Cu and Ni in ammonia solutions, in which the extraction of metals are 0.1-0.5 M solution of sodium bis-2-hydroxy-5-alkyl (C C 8 -C 9) benzylamine in kerosene

The disadvantages of this extractant include: high viscosity at a concentration in the organic solution over 0.5 M, not allowing to carry out extraction under these conditions; extraction properties rather weak amines with three or two benzyl radicals, especially during the extraction of acidic and neutral solutions, which is associated with weak electron density fed to the nitrogen atom of these radicals.

The present invention is to intensify the process of extraction of metals such as Zn, Cd, Te, Se, Sn, Cu, Co, Mo, Re, Ga, In, As, Fe, Cr, Pt, Rd, Ru, Rh, Ir, Au , Nb, Ta, Zr, V, La, Ce, Nd, U, Th from aqueous solutions by extraction with amine solutions and CHAO in an inert diluent.

The goal is achieved by the fact that extraction are concentrated solutions of amines and CHAO two organic radicals, each of which is a 2.4-dietiloktily. The extraction of lead and a mixture of amines or CHAO specified structure with amines or CHAO, currently used or other extractants. Complexes of amines and CHAO all studied contact elements were infinitely soluble in the inert diluents, such as kerosene, syntin, perchlorethylene, GC-3 and the concentration of the complex in the organic solution is determined by only the necessary technological viscosity of the latter, which is in turn determined properties diluent extractable anion, the type of extraction equipment, and so on. n. The authors used a solution of the amine and CHAO this concentration, the viscosity of the salts which are studied with the metal does not exceed ~ 20-25 cSt, which is sufficient for carrying out the process, even in the box-mixer-settler. The rich organic phase in this case was sufficiently concentrated on the extracted method. However, in some cases, for example when using centrifugal extracts may be used and more concentrated solutions of amines, in other cases it is sufficient extractant and less concentrated solution (for example, extraction Pt, Pd effluents from the production of these metals).

This amine structure is optimal and CHAO, t. K. If the secondary, tertiary amine or CHAO contains only one radical-2,4 dietiloktil, its properties are similar to those of NBHA amine, m. F. Property unlimited interoperability amine salt with an inert diluent disappears. When the number of such radicals (for tertiary amines and CHAO) organic solution viscosity increases sharply, making it technically unacceptable. Thus, the presence of even 16% of tri (2,4-dietiloktil) amine in di (2,4-dietiloktil) -amino increases the viscosity of 0.6 M amine solution in 5 times (see. Table. 1), while while the viscosity of a 0.6 M di- (2,4-diethyl-octyl) methylamine only 1.5 times the viscosity of a 0.6 M solution of di- (2,4-dietiloktil) -amine.

Reducing the radical chain length results in a loss of compatibility properties of the amine salt with an inert diluent, and a sharp increase and its solubility in the aqueous phase (a typical example - di-2-ethylhexylamine). Increasing the chain length of the radical - a deterioration of its hydrodynamic properties due to the greater viscosity of the organic solution and emulsifying ability.

Table. 1 shows the viscosity of solutions of salts of amines and acids; when saturated amines metals their viscosity increases, and the greater the higher the viscosity of the initial organic solution.

Interestingly, the structure of the said amines may themselves be known solutions for modifiers and amines CHAO inert diluents (for example, trioctylamine, tri-alkyl (C 7 -C 9) alkyl ALAN ammonium, trialkyl - TAMA), which is especially important for the extraction, for example , concentrated solutions of acids wherein the TBP is subjected to strong hydrolysis and degradation, but also to systems where higher alcohols and TBP inhibit extraction of metals (e.g., Mo and Zn during extraction). Moreover, having close to the known amines and CHAO solubility in the aqueous phase and the same ionic groups, they greatly simplify the system-amine modifier and diluent promote extraction. These extractants may be used in admixture with other extractants classes, such as neutral organophosphorus compounds, carboxylic and organic phosphorus acids and t. N.

Example. The extraction of metals from solutions carried out with concentrated solutions of amines and PJSC said structure in kerosene, perchlorethylene, syntin, RG-3. Used amines and buildings CHAO:

The concentrations of extractants mixed compositions shown in Table extractants. 2. When the extraction of each metal picking conditions and the composition of the aqueous phase is the most favorable for removal, or created the conditions encountered in the metal technology. The exchange capacity of the extractant in the latter case is not always completely used, including the non-optimal composition of the aqueous phase, and especially because of the small metal content in the aqueous phase equilibrium. Formulations of aqueous solutions and equilibrium extractable content of metal indicated in Table. 2. For some metals were determined their distribution coefficients between the organic and aqueous phases of the studied extractants and 0.5 M extractant CAF, which was compared with the distribution coefficients of the extraction solutions TOA or TEOA (the extraction of alkaline solutions), polar diluents. Distribution coefficients were determined for small (less than 1 g / l), roughly equal to the compared extractants, metal content of the equilibrium aqueous phase. As can be seen from Table. 2, amines and PJSC said structure extracted investigated metals distribution coefficients approximately equal ratios in the extraction of TOA or TEOA and much larger than the KAF extraction.

In all cases studied metals extraction delamination was observed a clear phase, third phase or the absence of precipitation, obtained satisfactory viscosity of organic solutions. Reextraction saturated organic phase was carried out by known methods.

Thus, when using amines and CHAO said structure in an inert diluent may produce concentrated solutions of metal organic sufficiently high extractability latter (at the TOA and TEOA). (56) Author's certificate USSR N 817086, cl. C 22 B 15/00, 1981.

CLAIM

METHOD FOR EXTRACTION OF METALS FROM AQUEOUS SOLUTIONS comprising extracting metals solutions of nitrogen-containing anion exchange resins containing at least two organic radicals in an inert diluent, characterized in that the metals extraction are amine solutions and / or quaternary ammonium bases, two organic radical in each of which are 2 4-dietiloktily.

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Publication date 15.03.2007gg