RU2359048C1 - Method of nickel and cobalt collective extraction from sulphate solutions, containing calcium, magnesium and manganese - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to nonferrous metals hydrometallurgy and can be used at processing of leaching solutions of oxidised nickel ores and other raw materials. Method of collective extraction of nickel and cobalt from sulphate solutions containing calcium, magnesium and manganese, includes extraction of nickel and cobalt di-(2,4,4)trimethylamyldithiophosphine acid (Cyanex 301) in thinner at presence of tertiary amine at molar correlation Cyanex 301: tertiary amines = 1:1÷1.5 in air atmosphere. After extraction it is implemented extract cleaning from admixtures. Re-extraction of metals is implemented by solutions of sulfuric acid at temperature 20-30°C.

EFFECT: simplification of separation process of nickel and cobalt from sulphate solutions.

3 cl, 1 dwg, 6 tbl, 7 ex

Description

The invention relates to hydrometallurgy of non-ferrous metals and can be used in the processing of leach solutions of oxidized nickel ores (OHP), oceanic nodules, sulfide raw materials and other products.

The need to create the present invention is caused by the complexity of existing methods for the extraction of cobalt and nickel from sulfate solutions containing impurities of magnesium, manganese and calcium, especially in the case of their high concentrations.

The known method (Method for the extraction of Nickel from solutions and pulps containing magnesium and / or manganese. I. A. Logvinenko, L. A. Marushinskaya and others. RF patent No. 200825, MKI C22B 3/24, publ. 15.11.93, bull No. 41-42), according to which it is proposed to use ion-exchange processes to extract cobalt and nickel from solutions and pulps after leaching of ore raw materials and separating it from magnesium and / or manganese. As a sorbent, vinyl pyridine ampholyte containing a carboxyl group is used. Nickel desorption is carried out with solutions of mineral acids (H ₂ SO ₄ , HCl) to obtain solutions containing 10-25 g / l of nickel.

The disadvantage of this method is the slow kinetics of sorption and desorption of Nickel, the inability to obtain concentrated Nickel eluates (more than 25 g / l). In addition, if cobalt is in the initial leach solution, then during sorption it tends to oxidize on the resin, which makes its desorption extremely difficult.

According to the method (A. Taylor, D. Cairns, "Technical development of the Bulong laterite project", (Paper presented in ALTA Nickel and Cobalt Pressure Leaching and Hydrometallurgy Forum, Perth, Western Australia, May, 1997)) OHP leach stock solution containing, g / l: 3.5 Ni; 0.3 Co; 1.0 Mn; 0.5 Ca and 8-10 Mg with an initial volume undergo two stages of extraction. First, cobalt is recovered with di- (2,4,4) trimethylpentylphosphinic acid (Cyanex 272), separated from nickel, calcium and, in part, from magnesium. The raffinate then goes through a nickel extraction cycle with branched monocarboxylic acids Versatic 10, where (nickel) is separated from calcium and magnesium. Reextraction of cobalt and nickel from the extracts is carried out with solutions of sulfuric acid.

The disadvantages of the method are:

- the need to use a double extraction cycle to isolate cobalt and nickel, while the aqueous solution passes through both stages of extraction, which leads to an increase in operating and capital costs;

- cobalt with Cyanex 272 is not extracted selectively, but with manganese and, in part, with magnesium, which leads to an increased consumption of regents (extractant, alkali and acid) and complicates the further processing of reextracts;

- the separation of nickel from calcium during the extraction of Versatic 10 is not complete, which leads to the deposition of gypsum at the stage of washing the extract or re-extraction of Nickel. This creates big problems with the process and leads to nickel losses.

In the method (JSPreston, ACDu Preez Separation of nickel and calcium by solvent extraction using mixtures of carboxylic acids. "Hydrometallurgy" (2000), 58, No. 3, p.239-250), in contrast to the previous method, a collective extraction of nickel and cobalt from sulfate solutions using a synergistic mixture of Versatic 10 and alkylpyridines as an extractant. From solutions containing, g / l: 5.0 Ni; 0.5 Co; 2.0 Mn; 0.5 Ca and 5.0 Mg, 0.1 Cu and 0.1 Zn for three countercurrent stages at pH = 5.8, the extraction of Ni and Co was> 99%, coextraction Mn = 4.2%, Ca = 1, 3% and Mg <0.04%. The metals were reextracted with a 0.25 M sulfuric acid solution in one step with a phase ratio of O: B = 3.33. The degree of reextraction was> 98%.

This method uses only one extraction cycle to extract nickel and cobalt, which distinguishes it from the method (A.Taylor, D. Cairns, "Technical development of the Bulong laterite project", (Paper presented in ALTA Nickel and Cobalt Pressure Leaching and Hydrometallurgy Forum, Perth, Western Australia, May, 1997)), however, it is not free from the disadvantages:

- the relatively high solubility of Versatic 10 during the extraction of metals (> 0.5 g / l), which can lead to loss of extractant and an additional stage of purification of solutions from the extractant;

- significant coextraction of manganese requires additional steps for washing the saturated extract from it;

- the complexity of the synthesis and industrial inaccessibility of alkylpyridines.

The closest in technical essence and the achieved result to the claimed method is a prototype method (I. Mihaylov, E. Krause, DFColton, Y. Okita, J.-P. Duterque, J.-J. Perraud. The development of a novel hydrometallurgical process for nickel and cobalt recovery from Goro laterite ore. (2000), CIM Bulletin, Vol. 93, No. 1041, p. 124-130), in which collective recovery of nickel and cobalt from sulfate solutions with a high content of magnesium, manganese and Calcium is carried out using di (2, 4, 4) trimethylpentyl dithiophosphinic acid as an extractant (Cyanex 301). The essence of the method is visible from the following.

From an OHR leach stock solution containing, g / l: 3-6 Ni; up to 0.6 Co; up to 3.0 Mn; up to 0.6 Ca and 1-10 Mg, from 0.05 to 0.012 Zn and <0.01 Cu, cobalt and nickel are extracted together in one cycle of 15 ^V / ₀ (0.33 M) with a solution of Cyaneke 301 in an aliphatic diluent. At a phase ratio of O: B = 1: 1–2, pH = 2–2.25, and a temperature of 55 ° C for three stages of countercurrent extraction, the combined extraction of nickel and cobalt was> 99.5%. Under these conditions, the extraction of calcium, magnesium and manganese is practically absent. In order to avoid oxidation of the extractant itself to disulfide, as well as of cobalt being extracted in the organic phase with atmospheric oxygen, extraction is carried out not under ordinary conditions, but in an atmosphere without oxygen, namely in a stream of inert gas (nitrogen or carbon dioxide). In the case of partial oxidation of the extractant (its degradation), an operation is provided for reducing the disulfide back to dithiophosphinic acid (Cyanex 301) with hydrogen obtained by contact of sulfuric acid with zinc or nickel powder.

Reextraction of nickel and cobalt is carried out with concentrated solutions of hydrochloric acid (6-7 mol / l) at four stages at a temperature of 60 ° C, the contact time of the phases at each stage is about 5 minutes. In this case, reextracts are obtained containing nickel 85 ÷ 90 g / l and cobalt from 6 to 10 g / l with a residual acidity of about 3 M hydrochloric acid.

The total liquid extraction cycle includes nine steps:

- 3 steps - the actual extraction of nickel and cobalt;

- 1 stage - washing the saturated extract from impurities with a solution of sulfuric acid;

- 4 stages of re-extraction of nickel and cobalt with hydrochloric acid;

- 1 stage - washing the circulating extractant from the chloride ion in order to prevent it from entering the extraction stage.

Significant disadvantages of the method are:

- the need for extraction in an inert atmosphere to prevent oxidation of the extractant and cobalt (II) in the organic phase to cobalt (III) with atmospheric oxygen, which significantly complicates the hardware design of the process;

- the need for periodic regeneration of the extractant from the resulting disulfide again to dithiophosphinic acid (Cyanex 301) using hydrogen, which not only complicates the process, but also creates an explosive and fire hazard situation, especially at elevated temperatures;

- the use of concentrated solutions of hydrochloric acid at the stage of reextraction at elevated temperatures makes the process more expensive not only due to the cost of the acid itself and increased energy consumption, but also because of the need to use special corrosion-resistant materials for the hardware design of the process due to the high aggressiveness of HCl. In addition, during hydrochloric acid reextraction, an additional step is necessary for washing the circulating extractant from the chloride ion in order to prevent it from entering the extraction stage. (Reextraction of metals with sulfuric acid in systems with individual Cyanex 301 is practically impossible).

The objective of the invention is the collective extraction of Nickel and cobalt from sulfate solutions containing calcium, magnesium and manganese. The technical result of the invention is to simplify the process by conducting extraction in air and preventing oxidation of the extractant and cobalt in the organic phase with oxygen by the air, and, accordingly, eliminating the regeneration of the extractant, as well as re-extraction of cobalt and nickel with sulfuric acid solutions

This goal is achieved in that, in contrast to the known method for the collective extraction of nickel and cobalt from sulfate solutions containing calcium, magnesium and manganese, including the extraction of nickel and cobalt di (2, 4, 4) trimethylpentyldithiophosphinic acid (Cyanex 301) in a diluent, washing the extract from impurities with sulfuric acid solutions and metal reextraction with mineral acid solutions, the process is carried out in an air atmosphere in the presence of tertiary amines with a molar ratio of Cyanex 301: tertiary amine = 1: 1.0 ÷ 1: 1.5, and kstraktsiyu solutions of sulfuric acid at a temperature of 20-30 ° C.

When Cyanex 301 is extracted by an individual extractant in open systems in air, the extractant is partially oxidized to form disulfide (reaction equation 1) and extracted cobalt (II) to cobalt (III) in the organic phase (reaction equation 2) with atmospheric oxygen.

where HR is Cyanex 301, and R-R is disulfide.

The resulting CoR ₃ complex is very inert; it is practically impossible to reextract it with solutions of mineral acids.

When trialkylamine (R'3N, TAA) is introduced into the organic phase containing Cyanex 301, a strong interaction takes place between Cyanex 301 and trialkylamine to form the stable adduct [R′3N · HR] (reaction equation 3)

As a result of the binding of Cyanex 301 to the adduct, reactions (1) and (2) practically do not occur and, accordingly, it is possible to carry out the process in an air atmosphere using conventional extraction equipment — mixer settlers or columns. In the known method (prototype) in order to avoid the occurrence of reactions (1) and (2), the process must be carried out in an inert gas atmosphere in special apparatuses that exclude the ingress of air oxygen into them. Since oxidative degradation of the extractant does not occur (reaction level 1), there is no need to regenerate the extractant, which takes place periodically in the known method (prototype).

The reaction (3) greatly simplifies metal stripping due to the formation of the same adduct R′3N · HR and a decrease in HR activity, as a result of which it is possible to reextract nickel and cobalt with sulfuric acid solutions practically in a stoichiometric ratio (reaction equation 4 is significantly shifted to the right) .

where M is Co or Ni.

Since cobalt in these systems does not oxidize in the organic phase and remains in the form of cobalt (II), it is quite simply reextracted with nickel. Reextraction takes place at a temperature of 20-30 ° C.

The use of sulfuric acid for reextraction significantly simplifies and cheapens the process, in comparison with the known method (prototype), due to its lower cost in comparison with hydrochloric acid, lower energy costs, and also due to the possibility of using cheaper structural materials, for example stainless steel and etc.

It is proposed to use mixtures with a molar ratio of Cyanex 301: tertiary amine 1: 1 ÷ 1: 1.5 and the pH of the solutions at the extraction stage is 6.0-6.6.

With a lower ratio of Cyanex 301: trialkylamine (<1: 1.5), the extraction of metals, mainly cobalt, deteriorates; with a larger (> 1: 1), the metal reextraction worsens due to the appearance of free trimethylpentyldithiophosphinic acid unbound in di (2, 4, 4) adduct; moreover, the extractant can be oxidized.

At pH <6.0, the extraction of metals, mainly cobalt, deteriorates; at pH> 6.6, the extraction of nickel and cobalt increases slightly, however, the extraction of impurities, mainly manganese, increases noticeably.

Reextraction of Nickel and cobalt is carried out with solutions of sulfuric acid, including in a mixture with metal sulfates (nickel, cobalt and others) at a temperature of 20-30 ° C.

As solvents, ordinary solvents from a number of aliphatic hydrocarbons (nonane, decane, kerosene, oil paraffins, etc.) are used, in some cases with the addition of modifiers (octanol, 2-ethylhexanol).

The following are examples of the proposed method.

Example 1

Table 1 shows the dependences of the extraction of cobalt and nickel, as well as the main impurity metals (Mn, Ca, and Mg) on the final pH values of the aqueous phases upon extraction with a mixture of Cyanex 301 and trialkylamine (TAA fraction C7-C9). The change in pH was regulated by introducing various amounts of solutions of sulfuric acid or ammonium hydroxide into the system. Extraction was carried out in an air atmosphere. The compositions of the extractant and the initial aqueous solution, as well as the experimental conditions are given in table 1.

The table shows that with an increase in pH, the extraction of cobalt and nickel increases, the optimal range of extraction should be considered a change in pH in the range of 6.0-6.6.

At pH <6.0, cobalt extraction is significantly impaired; at pH> 6.6, the extraction of nickel and cobalt increases slightly, however, the extraction of manganese increases noticeably. The coextraction of other impurities (Ca and Mg) is negligible, their content in the organic phase in all cases did not exceed 0.02 g / l. When separated from manganese, the metal separation coefficients (BNi / Mn and βСо / Mn) substantially depend on pH, however, in the optimal pH range they are quite high and vary in the range from 1660 to 53 for a cobalt-manganese pair and from 9400 to 370 for a nickel pair -manganese.

As can be seen, this system makes it possible to efficiently extract cobalt and nickel from solutions, practically without removing the main impurity elements (Ca, Mg, and Mn).

Table 1 The dependence of the extraction of D metals on acidity with a mixture of Cyanex 301 and TAA
Extractant: 0.4 M Cyanex 301 + 0.4 M TAA + 10% octanol in nonane.
The initial aqueous solution, g / l: Ni-4.75, Co-0.4, Zn-0.21, Mn-1.7, Mg-8.5, Ca-0.5. pH = 3.88.
Extraction conditions: Т = 19 ± 1 ° С, τ = 4 h, O: В = 1: 1. pH Ni, g / l Co, g / l Mn, g / l Mg, g / l Ca, g / l V.F. about D V.F. O.F. D V.F. about D V.F. about D V.F. O.F. D 0.43 4.68 0,07 0.015 0.396 0.004 0.01 - - - - - - - - - 0.68 4.67 0,078 0.016 0.396 0.004 0.01 - - - - - - - - - 3.91 4.0 0.625 0.156 0.35 0.05 0.14 1,6 0.00015 0.0001 7.0 0.004 0,0006 0.45 0.015 0,0333 4.99 2.2 2.5 1.14 0.325 0,075 0.23 1,6 0.00015 0.0001 8.0 0.004 0,0005 0.423 0.0155 0,0367 5.84 0.70 4.0 5.71 0.20 0.225 1,125 1.7 0,00075 0,0004 8.5 0.006 0,0007 0.45 0.015 0,0333 6.01 0.45 4.29 9,4 0.15 0.25 1,66 1.7 0.0017 0.001 8.5 0.008 0,0009 0.45 0.018 0,040 6.6 0.13 4.62 35.5 0,066 0.34 5.1 1.55 0.15 0,096 8.3 0.01 0.0012 0.45 0.02 0,044 8.50 0.0017 4.66 2740 0,0009 0.391 434 0.493 1,082 2,197 7.5 0.016 0.0022 0.45 0.02 0,044

Example 2

An example shows the possibility of re-extraction of nickel with solutions of sulfuric acid (worse than a re-extractable element in comparison with cobalt). The extractant was saturated with nickel using the sodium form of Cyanex 301. The remaining experimental conditions and its results are given in Table 2.

table 2 The effect of acidity on the re-extraction of Nickel in a mixture of Cyanex 301 with TAA The initial extractant (0.4 M Cyanex 301 (HR) + 0.4 M TAA + 10% octanol-1 in nonane) was contacted for 10 min at T = 20 ° С with 0.5 M NiSO ₄ , O: B = 1: 2. Ni obtained in the extract: 11.06 g / l (0.378 N). Reextraction conditions: O: B = 5: 1, τ = 1 h, T = 20 ° C. No.

г-экв./л

g-equiv. / l With _{Ni (c)} , g / l C _{Ni (o)} , g / l D * _ni ε%, the degree of stripping pH final one 1,52 40.3 3.0 0,074 72.8 4.0 2 2.06 53.41 0.792 0.015 92.8 2.2 3 2.52 53.41 0.866 0.016 92.1 1,2 four 3.02 52.82 1.027 0.019 90.7 5 3.53 50.47 1.262 0.025 88.6 6 4.12 47.71 1.541 0.032 86.1 7 5.07 46.07 2.186 0.048 80.2 8 6.09 43.43 2.935 0.068 73.5

D * is the distribution coefficient of metals equal to C _{M (o)} / C _{M (c)} ;

As can be seen from the table, nickel reextraction is quite effective in almost all cases (except for Nos. 1.7 and 8), however, the greatest degree of ε reextraction is achieved with a molar ratio of nickel and sulfuric acid from 1: 1 to 1: 1.25. The low distribution coefficients of nickel under these conditions make it possible in principle to concentrate nickel at the re-extraction stage by 10–20 times. Reextraction takes place under normal conditions - in the air and at T = 20 ° C.

Obviously, by a known method (prototype), such a variant of re-extraction is impossible.

Example 3

Joint coextraction of cobalt and nickel by a stoichiometric amount of sulfuric acid from a previously obtained extract was carried out. The experimental conditions and its results are given in table.3. As can be seen from the data obtained, back-extraction is quite effective for both metals in one step, and cobalt is back-extracted even better than nickel. Therefore, the effectiveness of stripping should be determined by the degree of stripping of nickel.

Table 3. Reextraction of Co and Ni from a mixture of Cyansx 301 + TAA Organic phase: 0.4 M HR + 0.4 M TAA + 10% 2-ethylhexanol in kerosene. The content in the extract, g / l: Ni = 6.5; Co = 0.85. Stripping Agent: 2.0 NH ₂ SO ₄ ; O: B = 5: 1; τ = 15 min, t = 22 ° C. Ni, g / l Co, g / l The degree of stripping, ε,% Note V.F. o.v. V.F. o.v. Ni With 1 stage of back extraction 28.0 1,0 3.8 0.02 84.6 97.6

Example 4

Nickel was back-extracted with a solution of sulfuric acid (2, ON) depending on the ratio of Cyanex 301 and TAA. The experimental conditions and its results are presented in table 4.

0.4 M HR (Cyanex 301) +0.4 M TAA

Table 4 The effect of TAA content in the HR + TAA system on nickel stripping with sulfuric acid The initial extractant 0.4 M HR (Cyanex 301) + TAA + 10% 1-octanol in nonane for contact with nickel was contacted with a 0.5 M solution of NiSO ₄ for 15 min at O: B = 1: 1 and T = 20 ° FROM. Stripping agent: 2.0 N (100 g / l) sulfuric acid solution. Experimental conditions: O: B = 5: 1; 22 ° C; phase contact time at each stage 10 min. N steps Ni _{(o) ref} ; g / l Ni _(c) ; g / l Ni _(o) ; g / l D one 11.19 50,2 1,03 0,021 0.4 M HR (Cyanex 301) +0.5 M TAA N steps Ni _{(o) ref} ; g / l Ni _(c) ; g / l Ni _(o) ; g / l D one 10.24 50.18 0.423 0.0084 2 0.423 1,58 0,091 0.058 3 0,091 0.179 0.059 0.33 0.4 M HR (Cyanex 301) +0.6 M TAA N steps Ni _{(o) ref} ; G / l Ni _(c) ; g / l Ni _(o) ; g / l D one 9.92 48.13 0,305 0.0063 2 0,305 1,5 0,023 0.015 3 0,023 0.05 0.013 0.26

The table shows that with an increase in the concentration of trialkylamine (TAA) and, accordingly, with a decrease in the ratio of Cyanex 301: TAA, nickel reextraction improves and almost complete reextraction is possible in two or three steps. The ratios in the range from 1: 1 (0.4 M Cyanex 301 and 0.4 M TAA) to 1: 1.5 (0.4 M Cyanex 301 and 0.6 M TAA) can be considered optimal - with large ratios (lower amount of TAA), metal reextraction will deteriorate, with smaller (more TAA), the extraction of nickel and cobalt will deteriorate.

Example 5

In this example, the possibility of implementing the method in the extraction-re-extraction cycle is demonstrated. The experimental conditions and its results are given in table 5. The table shows that for the 2nd stage of extraction, the extraction of nickel and cobalt from solutions is almost complete, while they are separated from the main impurities, partially extracted manganese is easily washed from the extract with dilute sulfuric acid solutions (see example 7). Almost complete metal back-extraction also occurs in 2 stages with a significant concentration of metals in the back-extracts.

Table 5 Extraction and re-extraction in the Cyanex 301 + TAA system. Extraction Extractant: 0.4 M Cyanex 301, 0.4 M TAA in nonane. The initial aqueous solution, g / l: Ni-6.0; Co-0.475; Mn-1.775; Ca-0.475; Mg-7.0; pH = 4.40. Experimental conditions: O: B = 1: 2 = 14 ml: 28 ml; T = 50 ° C; τ = 5 min. pH _ref RP _equal V (10.5 M NH ₄ OH), ml Ni, g / l Co, g / l Mn, g / l Ca, g / l Mg, g / l V.F. about V.F. about V.F. about V.F. about V.F. about one 3.80 6.5 0.53 1,2 10.5 0.12 0.675 1,64 0.1 0.465 0.013 7.2 0.017 2 4.30 6.5 0.15 0,0009 2,55 0,0006 0.248 - - 0.48 0.007 7.0 0.006 I. Reextraction
Org the phase is taken after the 1st stage of extraction (its composition in the above table).
Experimental conditions: 2.13 N H ₂ SO ₄ ; O: B = 5: 1; T = 22 ° C; τ = 5 min. N steps Ni, g / l Co, g / l Mn, g / l Ca, g / l Mg, g / l V.F. about V.F. about V.F. about V.F. about V.F. about one 52.0 0.268 3,313 0.008 0.5 0.0027 0.013 0.012 0,069 0.0027 2 1.12 0,0437 0.012 0,0004 0.004 0.0021 - - - -

Example 6

An example demonstrates the extraction characteristics of an extractant and its stability in extraction-re-extraction cycles under normal conditions (air atmosphere).

10 cycles of extraction and re-extraction of metals were carried out during the extraction of Co and Ni from a sulfate solution of the following composition, g / l: 6, O Ni; 0.475 Co; 1.775 Mn; 0.475 Ca; 7.0 Mg The pH of the stock solution is 4.15. Extractant - 0.4 M Cyanex 301 + 0.5 M TAA + 10 ^V / _o octanol in oil paraffins (N.P.). Each cycle consisted of one stage of extraction and two stages of reextraction.

Extraction: O: B = 1: 2; T = 50 ° C; τ = 15 min; _final pH = 6.2 (pH was adjusted with a 12 M solution of NH ₄ OH); n = 1 tbsp.

Reextraction: stripping agent - sulfuric acid solution = 2,13N (105 g / l); O: B = 5: 1; τ = 5 min; T = 25 ° C; n = 2 tbsp.

The raffinates and extracts were analyzed on Co and Ni after each cycle, the reverse organic phase was analyzed for the content of extractable metals (Co, Ni, and Mn) in it and for the whole composition of the main components (Cyanex 301 and TAA) after the experiment (10 cycle) . The data after the 1st, 5th and 10th cycles are given in table.6.

Table 6. Cycle number metal concentration in phases, g / l raffinate extract circulating extractant Ni Co Ni CO Ni With Mn one 1,2 0.14 10,2 0.67 - - - 5 1.25 0.15 9.9 0.65 - - - 10 1.25 0.14 10.1 0.66 0,034 0,0005 0,0005

Analysis of the circulating extractant showed that the contents of Cyanex 301 and trialkylamine in it practically did not change: the concentration of Cyanex 301 turned out to be 0.396 M, and TAA - 0.51 M.

From the obtained data it is seen that the extraction characteristics of the extractant, as well as its concentration have not changed, which indicates the stability of the extractant when it is used repeatedly. It is also seen that the back-extraction of metals with sulfuric acid occurs almost completely under normal conditions. Metals, including cobalt, do not accumulate in the circulating extractant, and this confirms that cobalt does not oxidize in the organic phase.

Example 7

Pilot tests were carried out to verify the method for extracting cobalt and nickel from sulfate solutions containing calcium, magnesium and manganese. The tests were carried out in an open atmosphere on extractors of the mixer-settler type with a mixing chamber volume of 50 ml and a sediment chamber of 250 ml. The installation consisted of 3 stages of extraction,

2 steps of washing the extract from impurities and 3 steps of stripping. A solution of 0.4 M Cyanex 301 mixed with 0.4 M TAA in petroleum paraffins was used as an extractant.

Extraction: initial aqueous solution, g / l: 5.0 Ni; 0.5 Co; 1.9 Mn; 0.46 Ca; 8.3 Mg; O: B = 1: 2 (0.2: 0.4 L / h); T = 50-55 ° C; τ = 10 min; pH in degrees - 6.2-6.5. Washing the extract from impurities: washing solution - H ₂ SO ₄ = 0.14N (6.9 g / l); O: B = 10: 1 (0.2: 0.02 L / h); T = 45-50 ° C; τ = 5 min taking into account phase recirculation; pH in degrees is 6.0-6.1. Reextraction: stripping agent - H ₂ SO ₄ = 4N (196 g / l); O: B = 10: 1 (0.2: 0.02 L / h); T = 25-30 ° C; τ = 5 min taking into account phase recirculation; reextract pH = 1-3.

The raffinates from the installation had the following composition, g / l: Ni = 0.003-0.08; Co = 0.0005-0.017; Mn = 1.7-2.0; Ca = 0.46-0.48; Mg = 8.0-8.2. The extraction of cobalt at the stage of extraction from the initial solution was not less than 96.2%, and nickel - 98.2%. Reextracts contained, g / l: Ni = 100-110; Co = 9.5-10.1; Mn = 0.1-0.2; Ca = 0.03-0.04; Mg = 0.04. The composition of the circulating extractant, g / l: Ni = 0.15-0.25; Co = 0.002; Mn = 0.002.

As can be seen, nickel and cobalt are re-extracted almost completely and do not accumulate in the circulating extractant. During the tests, 32 L of the initial solution was processed; the extractant completed 8 extraction-re-extraction cycles. During this period, its extraction properties have not changed. The concentrations of Cyanex 301 and trialkylamine remained the same as before the start of the tests - 0.4 M and 0.4 M, respectively.

The stability of the extractant is also confirmed by infrared (IR) spectra of organic phases. The spectra of the initial extractant and extractant after 8 cycles almost coincided, which indicates the absence of any changes in the composition of the organic phases. (see drawing).

Thus, it is shown that in contrast to the known method (prototype), where cobalt and nickel are extracted with Cyanex 301 in an inert atmosphere, the extractant is periodically regenerated with hydrogen, and the metals are reextracted with hydrochloric acid, in the proposed method, the process can be carried out under ordinary conditions without degradation of the extractant, and metals re-extracted with sulfuric acid solutions. Obviously, an extractant regeneration operation is not needed.

The data obtained show that the proposed method during its implementation will be much simpler and cheaper than the known one.

The drawing shows the IR spectra of organic phases: 0.4 M Cyanex 301 + 0.4 M TAA in oil paraffins.

1 - source extractant.

2 - reverse extractant after 4 cycles.

3 - reverse extractant after 8 cycles.

Claims (3)

1. A method for the collective extraction of nickel and cobalt from sulfate solutions containing calcium, magnesium and manganese, including the extraction of nickel and cobalt with di- (2, 4, 4) trimethylpentyldithiophosphinic acid (Cyanex 301) in a diluent, washing the extract from impurities and reextracting metals with solutions mineral acid, characterized in that the extraction is carried out in an air atmosphere in the presence of tertiary amines with a molar ratio of Cianex 301: tertiary amines = 1: 1 ÷ 1.5, and the metals are reextracted with sulfuric acid solutions at a temperature ur 20-30 ° C. 2. The method according to claim 1, characterized in that the stripping of metals is carried out with solutions of sulfuric acid at a molar ratio of sulfuric acid and stripping metals in the range from 1: 1 to 1.25: 1. 3. The method according to claim 1, characterized in that the metal stripping is carried out with mixed solutions of sulfuric acid and nickel or cobalt sulfate at a molar ratio of sulfuric acid to stripping metals in the range from 1: 1 to 1.25: 1 and achieving a total metal concentration of reextract up to 120 g / l.