RU2591910C1 - Electrowinning of cobalt from aqueous sulphate solutions of cobalt and manganese under static conditions - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: present invention relates to extraction of substances by electrowinning and can be used in non-ferrous and ferrous metallurgy, as well as for cleaning industrial and household waste. Method for extraction of cobalt and manganese from aqueous sulphate solutions includes electrolysis with extraction of cobalt on the cathode and deposition of manganese in anode sludge formed at the lead anode. Electrolysis is carried out using a titanium cathode and perforated partition dividing the cathode and anode space, at pH = 1.1-1.4 of aqueous sulphate solution and current intensity of 0.5-1.5 A.

EFFECT: technical result: production of metal cobalt of high purity.

1 cl, 6 dwg, 1 tbl, 3 ex

Description

The method relates to the field of extraction of substances by electroextraction and can be used in non-ferrous and ferrous metallurgy, as well as for the treatment of industrial and domestic wastewater.

Known methods for purifying a solution of cobalt from manganese by sorption of cobalt on anion exchange resin followed by its desorption with an acid solution [Khudyakov I.F., Klein S.E., Ageev N.G. Metallurgy of copper, nickel, related elements and design of workshops. M .: Metallurgy, 1993, p. 167].

The disadvantage of this method is the need to process a large volume of solutions, in addition, a large number of processing steps are necessary to obtain cobalt metal that does not contain manganese impurities.

The closest technical solution is a method of extracting cobalt and manganese from aqueous sulfate solutions [Patent RU 2212460 C2 (IPC C22B 3/20, publ. 09/20/2003)], including electrolysis with the release of cobalt at the cathode and the deposition of manganese in the composition of the anode sludge formed on the lead anode.

The disadvantage of this method is that the current efficiency and specific energy consumption are not optimal, the cathode cobalt contains microimpurities, and the cathode is difficult to grind.

The objective of the invention is to provide an effective method for cleaning solutions of cobalt from manganese in the technology for producing metallic cobalt.

The technical result that can be achieved by carrying out the invention is to obtain high purity cobalt metal.

This technical result is achieved in that in the known method for extracting cobalt and manganese from aqueous sulfate solutions, including electrolysis with the release of cobalt at the cathode and the deposition of manganese in the composition of the anode sludge formed on the lead anode, the electrolysis is carried out using a cathode made of titanium and a perforated partition, separating the cathode and anode spaces, at pH = 1.1-1.4 aqueous sulfate solution and current strength of 0.5-1.5 A.

The essence of the method is illustrated by the data of the table and FIG. 1-6, which indicate the conditions for electroextraction, the results of x-ray spectral analysis of cathode cobalt and the phase composition of the anode sludge.

The electrodeposition of cobalt was carried out from sulfate solutions; for the experiment, cobalt sulfate COSO ₄ and manganese sulfate MnSO ₄ of the pure grade and their crystalline hydrates CoSO ₄ · 7H ₂ O and MnSO ₄ · 7H ₂ O were used.

In this work, the processes were investigated at a pH of 1.1-1.4, which corresponds to similar processes of real production.

The studies were carried out in a stationary mode.

The concentration of metal ions in the starting electrolyte was, g / dm: 30-50 Co and 1 Mn.

The electrolysis was carried out in 3 stages for, h: I - 5-6, II - 5-6, III - 5-6.

At the end of each stage, the current strength and the voltage across the bath, the temperature of the electrolyte, and the concentration of Co and Mn in the solution were controlled. The electrical circuit of the installation is shown in FIG. 1. The cathode is titanium or aluminum, the anode is lead with a content of up to 1% silver. The electroextraction of cobalt in a stationary mode was carried out from sulfate solutions in a box-type electrolyzer with a volume of 400 cm with or without a perforated plexiglass partition separating the cathode and anode space of the electrolyte. The electrolyte during the extraction was heated from room temperature to 50-60 ° C.

The concentration of ions was controlled:

- the manganese concentration was determined by the volumetric persulfate method;

- the cobalt concentration was determined by the colorimetric method using nitroso-P-salt and weight with α-nitroso-β-naphthol.

The elemental composition of the surface of cathode cobalt and anode sludge was determined by X-ray spectral analysis using a CAMSCAN MV 2300 scanning electron microscope.

Practical examples

Example 1 (table, Fig. 2-4)

In FIG. Figure 2 shows the time dependence of the mass of cathode cobalt (Co) and anode sludge (Al) released during electroextraction: a - a titanium cathode and a partition, b - a titanium cathode and without a partition, - with a partition and aluminum and titanium cathodes.

From the table and FIG. 2, we can draw the following conclusions:

- From solutions with a baffle during electroextraction on a titanium cathode, a much larger cobalt mass is extracted at a current strength of 1.0-1.5 A compared to extraction at a current strength of 0.5 A.

- A much larger cobalt mass is extracted from solutions without a baffle during electroextraction on a titanium cathode at a current of 1.5 A compared to extraction at currents of 0.5-1.0 A.

- More cobalt is extracted from solutions with a baffle during electroextraction on a titanium cathode than during extraction without a baffle.

- From solutions with a baffle and without a baffle during electroextraction on a titanium cathode, approximately the same mass of anode cobalt slurry is extracted at a current strength of 0.5-1.5 A.

- From solutions with a baffle at a current strength of 1.0 A, a little more cobalt is extracted by electroextraction on an aluminum cathode than by extraction on a titanium cathode.

- A larger mass of anode sludge is extracted from solutions with a baffle at a current strength of 1.0 A during electroextraction on an aluminum cathode than with a titanium cathode.

In FIG. Figure 3 shows the results of X-ray spectral analysis of cathode cobalt obtained by extraction with a baffle on a titanium cathode at a current strength of 1 A. It can be seen that cobalt does not contain manganese impurities, only slightly oxidized from the surface facing the solution.

When using an aluminum cathode, the composition of the cathode cobalt contains oxides and hydroxosalts of cobalt, manganese, aluminum and lead.

Cathode stripping is easier with a titanium cathode than with an aluminum cathode. It should also be borne in mind the greater strength and resistance against oxidation of the titanium cathode in comparison with the aluminum cathode.

In FIG. Figure 4 shows an X-ray spectral analysis of the anode sludge obtained by extraction with a baffle and a titanium cathode at a current strength of 1 A. It is seen that the anode sludge contains oxides and salts of cobalt, manganese, lead, and silver. It has been established that such anode sludges are catalysts for oxidation processes.

Example 2 (table, Fig. 5)

In FIG. 5 shows the dependence on the time of current output of cobalt from solutions:

a - with a titanium cathode and a partition, b - with a titanium cathode and without a partition, c - with a partition and aluminum and titanium cathodes.

From the table and FIG. 5, we can draw the following conclusions:

- From solutions with a baffle during electroextraction on a titanium cathode, the current efficiency is greater at a current strength of 0.5 A compared to extraction at a current strength of 1.0-1.5 A.

- From solutions without a baffle during electroextraction on a titanium cathode, the current efficiency is greater at a current of 1.5 A compared to extraction at a current of 0.5-1.0 A.

- From solutions with a baffle during electroextraction on a titanium cathode, the current efficiency is an order of magnitude greater than during electroextraction without a baffle.

- From solutions with a baffle and without a baffle at a current strength of 1.0 A during electroextraction on aluminum and titanium cathodes, the current output is approximately the same.

Example 3 (table, Fig. 6)

In FIG. Figure 6 shows the time dependence of the specific energy consumption: a - with a titanium cathode and a partition, b - with a titanium cathode and without a partition, c - with a partition and aluminum and titanium cathodes.

From the table and FIG. 6, we can draw the following conclusions:

- From solutions with a baffle during electroextraction on a titanium cathode, the specific energy consumption is less at a current strength of 0.5-1.0 A compared to extraction at a current strength of 1.5 A.

- From solutions without a baffle during electroextraction on a titanium cathode, the specific energy consumption is less at a current strength of 0.5 and 1.5 A compared to extraction at a current strength of 1.0 A.

- Of solutions with a baffle during electroextraction on a titanium cathode, the specific energy consumption is less than with electroextraction without a baffle.

- From solutions with a baffle and without a baffle at a current strength of 1.0 A during electroextraction on aluminum and titanium cathodes, the specific energy consumption is approximately the same at the initial extraction time, and when time is more than 10 hours, the specific energy consumption is less during electrolysis on a titanium cathode.

Claims (1)

A method of extracting cobalt and manganese from aqueous sulfate solutions, including electrolysis with the release of cobalt at the cathode and the deposition of manganese in the composition of the anode sludge formed on the lead anode, characterized in that the electrolysis is carried out using a cathode from titanium and a perforated partition separating the cathode and anode spaces at pH = 1.1-1.4 aqueous sulfate solution and current strength of 0.5-1.5 A.

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