RU2698083C1 - Method for selective extraction of iron (iii) and manganese (ii) from aqueous solutions - Google Patents

Abstract

FIELD: hydrometallurgy.

SUBSTANCE: invention relates to hydrometallurgy of non-ferrous metals and can be used in processing concentrates, industrial products and solid wastes containing metals. Method involves contacting the extractant and the solution, stirring the mixture, settling and separating the phases. First, extraction of Fe (III) ions with tributyl phosphate is carried out from an aqueous solution with concentration of 3N HCl, 240 NaCl g/dm³ and temperature of 60 °C is added portionwise with minimum contact time of the solution and extractant. Method then includes re-extraction of iron ions from extract with water with precipitation from solution of oxide Fe₂O₃. Manganese precipitation is carried out from raffinate with ammonia while blowing solution with air at pH 8–8.5 and temperature of 50–55 °C.

EFFECT: technical result consists in efficiency of selective extraction of Fe (III) and Mn (II) ions from aqueous solutions.

1 cl, 3 dwg, 1 tbl

Description

The invention relates to the field of hydrometallurgy of non-ferrous metals and can be used in the processing of concentrates, industrial products and solid waste containing metals.

Known methods for the extraction of ions of Fe (II) and Mn (II) by their hydrolytic deposition from aqueous solutions [Voldman G.M., Zelikman A.N. Theory of hydrometallurgical processes. - M., Metallurgy, 1993, p. 303-307].

The disadvantages of the methods are that the selective extraction of iron ions and non-ferrous metals from such solutions by precipitation is difficult. Fe (II) ions are hydrolytically deposited together with the main non-ferrous metal ions. Fe (III) ions precipitate in a more acidic region, but non-ferrous metal ions and organic impurities also precipitate with them, since Fe (III) ions are coagulants.

The closest technical solution is a method for extracting iron (III) from an aqueous solution using tributyl phosphate (TBP) as an extractant [RF Patent 2572927, C22B 15/00, C22B 3/16, C25C 1/12, application 2014136589/02, priority 9.09 .2014, publ. 01/20/2016 BI No. 2 Voropanova L.A., Kokoeva N.B. The extraction of iron (III) ions from aqueous solutions with tributyl phosphate], including contacting the extractant and the solution, mixing the mixture, settling and phase separation, extraction is carried out from an aqueous solution with a concentration of 3 N. HCl, 240 NaCl g / dm ³ and a temperature of 60 ° C by portioned introduction of TBP with a minimum contact time of the solution and extractant.

The disadvantage of this method is that the optimal conditions for the extraction of Fe (III) and Mn (II) ions from aqueous solutions of a mixture of their salts have not been identified.

The objective of the invention is to determine the optimal conditions for the selective extraction of Fe (III) and Mn (II) ions from aqueous solutions of a mixture of their salts.

The technical result that can be obtained using the invention is the efficiency of extraction of Fe (III) and Mn (II) ions from aqueous solutions.

This technical result is achieved by the fact that in the known method for extracting Fe (III) and Mn (II) ions from aqueous solutions of a mixture of salts by extraction with tributyl phosphate, including contacting the extractant and the solution, mixing the mixture, settling and phase separation, the Fe (III) ions are first extracted ) tributyl phosphate, from an aqueous solution with a concentration of 3n. HCl, 240 NaCl g / dm ³ and a temperature of 60 ° C with the introduction of TBP at a minimum contact time between the solution and the extractant, then the iron ions are reextracted from the extract with water, and the Fe ₂ O ₃ oxide is precipitated from the solution and the manganese is precipitated from raffinate with ammonia when the solution is purged air at pH = 8-8.5 and a temperature of 50-55 ° C.

.The essence of the method is illustrated by the data of FIG. 1-2 and the table in which the phase contact time, temperature, residual concentration of C, g / dm ³ , metal ions in the raffinate, distribution coefficient D = C _org / C _water = (C ₀ / C-1) ⋅ (V : O), the extraction of metals in the organic phase E,% of the mass of the original, separation coefficient

.

Practical examples

Example 1

Extraction from aqueous solutions of MnCl _{2 by} tributyl phosphate.

To prepare the solutions used salt MnCl ₂ ⋅ 4H ₂ O

From an aqueous solution of MnCl ₂ with a concentration of 8.46 g / dm ³ Mn, 3n. HCl, 240 NaCl g / dm ³ and at a temperature of 20 and 60 ° C, Mn (II) ions were extracted by portioned introduction of TBP.

The extraction was carried out with stirring and constant pH of 30–50 min; solutions of NaOH and HCl were used as neutralizers. Temperature 20-60 ° C.

The extraction of Mn (II) ions as a result of extraction was,% of the mass of the original: 0.1 at 60 ° C and 2.1% of the mass at 20 ° C.

Thus, under the indicated conditions under which Fe (III) ions are extracted, Mn (II) ions are practically not extracted.

Example 2 (table, Fig. 1)

Tributyl phosphate (TBP) was used as an extractant. To prepare the solutions used salts of MnCl ₂ ⋅ 4H ₂ O and FeCl ₃ ⋅ 6H ₂ O.

The concentration of metal ions in the initial solution of C ₀ was, g / dm ³ : 19.9-24.3 Mn (II) and 19-29 Fe (III).

The extraction was carried out with stirring and constant pH of 30–50 min; solutions of NaOH and HCl were used as neutralizers. Temperature 20-60 ° C.

The table shows the results of extraction with batch, stepwise use of TBP at t = 20 and 60 ° C, C ^HCl = 3 n, C ^NaCl = 240 g / dm ³ . The extraction was carried out in 5 stages, TBP with a volume of V _TBP = 0.02 dm ³ , O: B = 1: 5 was used at each stage, the total use of the volume of TBP was V _TBP = 0.1 dm ³ , ΣО: В = 1: 1 , the extraction time at each stage of 10 minutes

In FIG. 1 according to the table shows the results of stepwise extraction at t = 20 and 60 ° C and the extraction time at each stage of 10 min from solutions with a concentration of C ^HCl = 3 n, C ^NaCl = 240 g / dm ³ and C _ref , g / dm ³ : 19.9-24.3 Mn (II) and 10-29 Fe (III);

a - dependence of the residual concentration of iron and manganese on the number of stages of extraction,

b - the dependence of the extraction of iron and manganese on the number of stages of extraction.

As follows from the data of the table and FIG. 1 extraction of manganese does not exceed,% of the mass: 1.5 at 60 ° C and 7.2 at 20 ° C, almost complete extraction of iron is achieved in 3 stages, so the extractant consumption can be reduced by more than 1.7 times.

The presence of manganese ions in the solution practically does not affect the results of iron extraction.

Reextraction of iron ions from the extract was carried out with distilled water with precipitation from a solution of oxide Fe ₂ O ₃ .

Example 3

After extraction of iron, manganese was precipitated from raffinate with an aqueous solution of ammonia with a concentration of 150 g / dm ³ at pH = 8-8.5 and a temperature of 50-55 ° C with purging the solution with air:

MnCl ₂ + 2NH ₄ OH + 1/2 O ₂ + H ₂ O = Mn (OH) ₄ ↓ + 2NH ₄ Cl

Then the pulp was filtered, the precipitate Mn (OH)_four subjected to drying and calcination to obtain MnO₂.

The resulting solution of ammonium chloride is neutralized by evaporation, followed by crystallization of ammonium chloride into a commercial product. Separate production of gaseous basic (NH ₃ ) and acidic (HCl) reagents can be obtained by the interaction of the salts (NH ₄ ) ₂ SO ₄ and NH ₄ Cl (Fig. 2). The process of metal extraction occurs in closed production without the release of environmentally hazardous components into the environment.

In FIG. 3 is a flow chart of the extraction of iron and manganese ions from aqueous solutions of their salts.

Iron extraction from chloride solutions of a mixture of salts of MnCl ₂ and FeCl ₃ C ^HCl = 3 n, C ^NaCl = 240 g / dm ³ , ΣO: B = 1: 1, each stage O: B = 1: 5, ΣO: B = 1 :one

Temperature 20 and 60 ° С

Claims (1)

A method for the selective extraction of Fe (III) and Mn (II) ions from aqueous solutions of a salt mixture by extraction with tributyl phosphate (TBP), comprising contacting the extractant and the solution, mixing the mixture, settling and phase separation into the extract and raffinate, characterized in that the ions are first extracted Fe (III) tributyl phosphate from an aqueous solution with a concentration of 3n. HCl, 240 NaCl g / dm³ and a temperature of 60 ° C by portioning the introduction of TBP at a minimum contact time of the solution and the extractant, then iron ions are extracted from the extract with water and precipitation of Fe oxide from the reextract solution₂O₃but manganese is precipitated from raffinate with ammonia when the solution is purged with air at a pH of 8-8.5 and a temperature of 50-55 ° C.

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