SU801846A1 - Method of preparing cation-exchange extracting agents for extraction - Google Patents

Description

This invention relates to hydrometallurgy of non-ferrous metals and, in particular, to extraction recovery and metal separation. A known method of preparing cation-exchange extractants, for example, carboxylic acids, for extraction, includes treating them with an alkaline or alkaline earth metal compound with conversion to alkaline or alkaline earth form l. According to a known method, the conversion of the extragenta into an alkaline form is carried out by introducing crystalline alkali in order to prevent the dilution of the initial metal containing solutions. The disadvantages of this method are the high cost and scarcity of alkaline reagents, the difficulty of controlling the pH value of the equilibrium aqueous phase during extraction, the relatively low delamination rate and the complete separation of the organic and aqueous phases. The aim of the invention is to exclude the consumption of alkrych and to intensify the process. C | al is achieved by processing the extractant by electrolysis in an electrolyte from an alkaline or alkaline-earth compound. In the electrochemical treatment of carboxylic acid together with an electrolyte from an alkali metal or alkaline earth metal (chloride, nitrate, sulfate, widely used in the drive) electrolyte, the extractant becomes 4Yey (co-chemical properties. In the process of electrolytic charging to an alkaline or alkaline earth form, carboxylic acid undergoes three-phase emulsification with gaseous hydrogen released at the cathode and simultaneous saponification, as a result of which the reactivity of the extractant is equalized of the entire volume and significantly increased as compared with the ordinary administration of the crystalline alkali.

This method is carried out as follows.

Cation exchange ex-agent gulf-. into the cathode zone of a single-phase electrolytic cell containing an electrolyte of alkali or alkali earth salt. Due to the difference in density, the organic layer is located above the water layer. A constant electric current of low voltage is applied to the system. The stirring of the extractant and the electrolyte in the process of electrical treatment is carried out by recycling the electrolyte through the organic layer.

When using an anion exchange membrane, a saturated solution of either an alkali or alkaline earth salt is used as the electrolyte of the cathode zone (catolite). As the electrolyte anodic aoHbf (anolyte) use a weaker solution of the same salt.

When using the kagionig membrane, a saturated solution is introduced from the anodic zone (only common salt-salt can be used), and a weaker solution of the same solc can be used as a catholyte.

The degree of saturation of a cation-exchange extrageng with an alkali or alkaline-earth metal during electrotreatment is determined from the conditions for neutralizing the free acidity of the solution subjected to extraction processing to the exchange of the one or sum of nonferrous metals into metals.

The degree of saturation of the cata-exchanger extractant with an alkali or alkaline earth metal during electrochemical processing is controlled by changing the electrode (cathodic) current density, the time by the ratio of the electrolyte: extragene volumes and is controlled by changing the density of the extractant by direct measurement with densimeters (hydrometers). According to the difference in densification of the extractant, the amount of alkaline earth metal transferred to the organic phase of the alkaline clique is determined by and after electrotreatment.

The method worked out on a laboratory scale.

Example 1. 60 ml of higher azocarboxylic acids (VIC) fractions were introduced into the zone of a diaphragm electrolyzer (diaphragm is inert - skin), containing ZOO ml of saturated

of sodium chloride solution (Passenger density 1200 g / cm). The original anolyte solution of the same salt with a concentration of 10 g / l. Anolyte volume - 360 ml. The cathode is stainless steel, the anode is graphite. The electrical preparation of the VIC was conducted for 2.5 hours at a current of 3 A (cathode and anodic current density — 25 A) and a voltage of 4.6 V.

As a result, the energy contractor

charged to the sodium form — an alkali salt of the VIC fraction was obtained,.

The proposed method was used for the extraction processing of copper-cad.

Miy-zinc-containing heap leaching solutions. to produce selective zinc-cadnese and copper reextracts. Content of the components in the initial solution, mg / l :. copper 600 cad

Mi 60, zinc 1700, ferric iron 1300, calcium 520, magnesium 37O, free acidity of sulfuric acid 150O (pH 1.85-1.90).

The processing of the solutions was carried out

51On the following scheme: collective ext; - nuclear extraction of iron, copper, cadmium and zinc, followed by selective reextraction of first zinc with cadmium, then copper n, and finally, iron (three

iron in the pH range of hydrolysis is to the left of copper, the most acidic of the valuable components, and therefore extracted along with them; magnesium and calcium in the pH range of hydrolysis are to the right of zinc — the least acidic of the indicated valuable components and therefore not extracted),

The extragtect charged to the sodium form was in contact with the solution at the ratio of the volumes of the organic and aqueous phases O: B 1: 5; The pH value of the equilibrium WATER phase (rf) was 6.25. The content of valuable components in the raffinate — the sleeves — the removal of copper and cadmium into the organic phase — 99.9%,

zinc over. With almost complete extraction of the valuable components of the solution, a fivefold degree of concentration of metals and a reduction in the volume of the material flow was achieved.

Comparative character (ethics of the speed and completeness of separation of the organic and aqueous phases, as well as other parameters during extraction using the proposed and known method of preparation

extractant is given in the table.

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From the xylective extract at the 1st stage of reextraction at a pH of 4.75, the obtained zinc-cadmium re extract with the use of a copper sulfate solution (the part of the reextractor of the 2nd stage is used), at the 2nd stage of reextraction at pH - 2.0-1.7 - copper reextract using sulfuric acid solution as extractant. Example 2. 6O ml of synthetic fatty acids (FFA) of the industrial C-CQ fraction were loaded into the cathode zone of a diffraction electrolyzer (anion-exchange membrane MAK-B) containing ZOO ml of a saturated solution of sodium chloride (catholyte density 12OO g / dm anolyte - {solution of sodium chloride with a concentration of 15 g / l, anolyant volume 360 m Cathode — stainless steel, anode — graphite. The electrical preparation of FFA was carried out for 3 hours and 50 minutes in the 2nd stage (2 hours in the first stage and 1 hour 5O min - in the second). The spent electrolyte stage 1 was replaced with a fresh, saturated solution of sodium xnoDHctoro The current strength during electrical treatment is 2 A (cathode and anode and gok density 182 A / m), voltage 4-5 V. As a result, an alkaline salt of FFA fraction with a density of 990 g / dm is obtained (the initial density of carboxylic acid is 918 g / dm). Extractant contains 72 g / l of sodium. The extractant prepared in this way was used for the extraction processing of matt solutions from cutting the copper concentrates to obtain rich copper-sulphate reextractors suitable for separating marketable copper by autoclaving reduction or electrolyzing m with insoluble anodes. The content of components in the initial solution, g / l: copper 33.9, total iron 4.99. Wednesday - sulfuric acid. The pH of the initial solution is 2.5-3.0. The processing of the solutions was carried out according to the following scheme: a joint extraction of iron and copper at a pH of ae.v. - 4.5-5.0 to obtain a collective copper-jelly extract; the subsequent selective stripping with sulfuric acid, first copper, pH 2, then iron at. The extragent charged to the sodium form was in contact with the stock solution for 1 min at an OJB ratio of 1: 1. Extraction of copper in the organic phase was about 10%. Copper leaching was carried out at 1 stage of extraextraction at 3: 1 with a stoichiometric amount of sulfuric acid (in: an aqueous solution) at pH -1.7 - 2.0 and the temperature of the loading medium of the SO of C. The total degree of copper concentration is 3 The copper content in the reextract is about 1OO g / l with an iron content of 1.5 g / l. The extraction of ferric iron was carried out in the second stage at i.H0, 15 with sulfuric acid solution.

The resulting meano-sulfate solutions can be processed into powdered or cathode copper.

Example 3. 6O ml of the same FFA fraction was poured into the cathode zone of a pyapragm electrolyzer (membrane; - aluminum ionite MAK-2 wound) containing 300 ml of a saturated electrolyte of magnesium chloride (catholyte density 1303 g / dm). The starting anolyte is a solution of the same salt with a concentration of 15 g / l. Anolyte volume - 360 ml. The cathode is stainless steel, the anode is graphite. The electrical preparation of SLC was conducted at a current of 2 A. (cathode and anodic current density 182 A / m), voltage - 5 V for 2 hours.

As a result, the alkaline earth salt of the FFA fraction with a density of 935 g / dm (the initial density of carboxylic acid is 913 g / dm). The extract contained 22 g / l magnesium. ..

The extractant charged to the magnesium form was used to process the same solution as in Example 2, O: B 2: 1. PH value rv.v. after collective extraction of iron and copper-4.65. The separation of the phases. Very fast (not more than 1.5 minutes) and clear (the volume of the loaded extract is equal to the volume of the initial extractant). Further processing of the extract and the technological parameters obtained are identical to those indicated in the example.

2. Extraction of metzn to the final solution, calculated from the initial liquor - 99.7%.

Thus, the use of the proposed method eliminates the need for the consumption of scarce and expensive crystalline alkali; dramatically increase the speed of the process and ensure perfect completeness of phase separation, even with a high concentration of recoverable metal; significantly increase the working capacity of the extractant; to ensure the optimum pH of the equilibrium aqueous phase.

Formula 3 and Breasts

A method of preparing cation-exchange extractants for extraction, comprising treating them with an alkaline or alkaline earth metal compound with conversion into an alkaline or alkaline earth form, characterized in that, in order to avoid alkali consumption and process intensification, the extractant is treated by electrolysis in an electrolyte from an alkaline or alkaline earth metal compound.

Sources of information taken into account in the examination

1. LM Gindin and others. The separation of metals by the method of exchange extraction by fatty acids under the influence of alkali. Journal of Inorganic Chemistry, 1960, vol. 5, no. eight.

Claims (1)

SUMMARY OF THE INVENTION A method for preparing cation-exchange extractants for extraction, comprising treating them with an alkali or alkaline earth metal compound to be converted to an alkaline or alkaline earth form, characterized in that, in order to eliminate alkali consumption and intensify the process, the extractant is treated by electrolysis in an electrolyte from alkaline or alkaline earth ΗΟΓφ connections.