SU742476A1 - Method of metal reextracting from organic phase - Google Patents

Description

(54) METHOD OF REEXTRACTION OF METALS FROM ORGANIC PHASE

The invention relates to chemical metallurgy, in particular, to the technology of liquid reextraction of metals, and can be used to process metal-containing organic extracts in order to extract from them and separate metals - members of a series of pH hydrolysis, as well as to regenerate the extractant. A known method of metal extraction from the organic phase involves the treatment of the organic phase with a constant electric current in an electrolyte-aqueous solution of an inorganic compound (mineral acid). 1 The disadvantage of this method is its aggressiveness, toxicity and its relative high cost associated with the use of toxic, aggressive reagents - mineral acids, their transportation, storage, 15) needles of laziness of solutions of the required concentration. The purpose of the invention is to eliminate the aggressiveness and toxicity of the process. This goal is achieved by using an alkaline or alkaline earth metal salt solution as an electrolyte, and the process is carried out with a diaphragm separating the anode and cathode spaces, the organic phase — electrolyte system being placed in the anode space. The method is carried out as follows. The metal-containing organic extract is poured into the anode zone of the diaphragm electrolyzer containing the alkali or alkaline earth electrolyte (sulfates, nitrates, sodium, potassium, magnesium chlorides, etc., having a wide natural distribution). Due to the difference in density, the organic phase is located above the anolyte (electrolyte of the anode zone), which is recirculated in the anode zone through the organic layer using a pump. With a recirculation mode correctly chosen, the organic phase is not entrained with the anolyte, but is always located above it. The cathode is any electrically conducting material. The anode is chosen insoluble (for example, graphite, coal, etc.) or soluble (from a particular metal). With regard to the composition of electrolytes and the type of diaphragm used, the method has the following features. Since reextraction is carried out in the anodic one: it is not, the electrolyzer must be diaphragm-free. As the diaphragm can serve as an anion exchange resin, and cation resin membrane. When using an anion exchanger membrane, a solution (preferably saturated) of an alkali or alkaline earth salt is used as a catholyte (electrolyte of the cathode zone); the composition and concentration of the anolyte does not matter (it is possible to use a weaker solution of the same salt as in the catholyte). When using a cation-exchange membrane, a solution of (preferably saturated) alkali salt is used as an anolyte; the composition and concentration of catholyte do not matter (it is possible to use a weaker solution of the same salt as in the anolyte). When a permanent electrolyte system is applied to the system, an excess current is accumulated in the ions (the pH value at the same time is up to 1.5-2.5), which, when the anolyte is recirculated through the oggy layer, causes the metal to be re-extracted. The latter, combined with the counterion, the anion of the ACID composition of the corresponding salt (for example, SO4), forms soluble in water, then the salt of the re-extracted metal is in water. At the same time, the metal to be re-extracted goes into the aqueous phase in the form of a mineral acid salt solution. The organic phase is charged to the H form. Since the formation of a reagent that causes metal reextraction and metal reextraction occur simultaneously, since they are combined in time and in the apparatus, the accumulation of excess (free) acidity against stoichiometry on cations contained in the solution is eliminated: how much reextractant is formed, so much and is spent on reextraction. The resulting solutions are neutralized acidic (not containing free acid), the pH of such solutions is 2-3, but all annones are equivalently bound to metal cations. The amount and concentration of hydrogen ions generated in the anode zone (and therefore the amount of highly-separated metal, i.e. the degree of metal re-extraction), in accordance with Farad's law, is determined by the amount of electric current passed through the electrolyte. The magnitude of the electrode (Edd) or bulk (Zdb) current density at this value does not matter, it can be changed within wide limits (generally Zdl or about 0, A / m). With ;; (the electrolyte and the given current strength of a stett of metal stripping from the organic phase is determined only by the duration of electrical treatment. The minimum current density O1 declines visually by starting the emission of gases at the electrodes: hydrogen at the cathode and oxygen at the anode. Speed, degree and intensity reextraction is controlled by changing the electrode or bulk current density, electrical work time, the ratio of the volumes of anolyte: a metal-containing organic extract. The first factor makes it possible to stretch or shrink reextraction process over time and thus provide the necessary degree of selection of metals from the organic phase and the speed of reextraction. The second factor allows for the process of reextraction in a continuous mode that is easily automated and provides a given degree of reextraction. The third factor is designed to provide the necessary degree of enrichment of reextract to the target ( as a result of the electrochemical treatment of the metal-containing organic extract, a regenerated organ is obtained nical phase, and reextract as - an aqueous mineral salts solution reekstragiruemogo metal. When processing collective extracts containing a group of metals, reextraction is staged. First, the least acidic reextract from metals contained in the organic phase is obtained, then a second reextract with a more acidic metal, etc. up to the regeneration of the extractant /, the gaseous products of the re-extractive process are non-toxic, hydrogen on the cathode, and oxygen on the anode. The following examples cover the entire pragmatic pH range of hydruine, on the left flank of which is 3-valent iron, on the right - magnesium. Copper is in an intermediate position. Example 1. Acid-free copper extraction from organic extract containing copper soap. In the anodic zone of the diaphragm electrolyzer (cation membrane MK-40) filled with sodium sulfate electrolyte, 100 ml of synthetic fatty acid copper soap from the Su-C fraction with copper content in the organic phase of about 36 g / l is injected. The anode is graphite, the cathode is made of stainless steel. Anolyte - saturated at 19 ° С sodium sulfate solution with a density of 1147 g / dm. Anolyte volume - 475 ml. Catholyte is a solution of the same alkali salt with a sulfate concentration of 100 g / l. The volume of catholyte - 250 ml. Electroprocessing of the copper extract is carried out by 1FI current strength (cathodic current density 232 anodic - 294 A / m) and voltage 5V for 4 hours. As a result, copper is re-extracted into the aqueous phase, and the organic phase is regenerated and reused (organic phase density after reextraction of equal initial density). In order to control the degree of electrolytic reextraction of copper, the organic phase after electrotreatment is the initial copper

extract 100.0 36,425 3.6425 100.00

Electrolytic

copper cut 475.0 7.66 3.6385 99.89

As seen from the above two, the degree of copper reextraction is 9939% with simultaneous production of re-extract without excessive syrupness (pH about 2).

Example 2. Acid-free re-production of magnesium from an organic extract, with magnesia soap.

Under the instrumental conditions and electrical treatment modes identical to example 1, 100 ml of magnesian soap of the same

The original magnesium extract 100,0 6,46 0,646 100,00

Electrolytic magnesium reextract

Regener1yuvanna

organic

phase

Control

magnesium

reextract

The solution is completely treated with a solution of sulfuric acid until the pH of the aqueous solution is 0.65, and the copper content is determined in the resulting control reextract. The copper balance by electrolytic reextraction products is given in table 1.

Table. one

100.0

0.11

100.0 0.04 0.004

fractions of € 7-09 with magnesium content in the organic phase of 6.46 g / l. Anolyte volume - 425 ml of catholyte - 275 ml. Stripping time 2 h 50 min. The entire Nianndi from the organic phase goes into a water reextract with a pH of about 2.0. The downstream control sulfuric acid recovery of the organic phase (after an elec- trical absorption) does not reveal magnesium in the control reextract with a pH of 1.1. Balance mapsh for electrolytic reextraction products are fedden in table. 2. Table2.

425.0 1.52 0.646 100.00

100.0

0.00

Not found, 0 0

Claims (1)

Claim A method for reextracting metals from the organic phase, which involves treating the organic phase with direct electric current in an electrolyte - an aqueous solution of an inorganic compound, characterized in that, in order to exclude aggressiveness and toxicity of the process, an alkali or alkaline earth metal salt solution is used as the electrolyte and the process is carried out with separation anode and cathode spaces by a diaphragm, wherein the organic phase electrolyte system is placed in the anode space.