RU2590806C2 - Method for sorption extraction of selenium, tellurium and arsenic from aqueous solutions - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to hydrometallurgy, particularly to a method for sorption extraction of selenium, tellurium and arsenic from solutions. Proposed method comprises adding soluble indium compounds to solution of extracted elements before sorption. Number of indium compounds must be greater than number of extracted elements in solution. At room temperature there is more rapid achievement of full extraction of said elements from solution. Use of indium in cationic form prevents undesirable reactions with formation of insoluble compounds.

EFFECT: technical result is use of indium salts for intensification of sorption of selenium, tellurium and arsenic on amino thioester sorbents.

1 cl, 1 tbl, 4 ex

Description

The invention relates to the field of hydrometallurgy, and in particular, to methods for sorption extraction of selenium, tellurium and arsenic from solutions.

Removing toxic elements from a variety of natural and man-made objects is an integral task of numerous metallurgy processes. The difficulty in removing toxic elements that are heterogeneous in nature lies in the fact that there are no satisfactory chemical methods that can simultaneously and completely remove elements with different chemical properties.

Known methods of extraction for the analysis of toxic elements, including selenium, tellurium, from solutions using elemental sulfur / 1. GOST USSR 12645.11-86. Method for determination of selenium. // 2. GOST USSR 12645.12-86. Tellurium determination method. /. These sources describe the recovery of selenium and tellurium by coprecipitation with elemental sulfur. The main disadvantage of the proposed method is the impossibility of joint extraction of selenium and tellurium, because the extraction of each of these elements requires the creation of individual conditions.

The combined extraction of selenium and tellurium by this method is possible with a modification of the method described in / 3. B.Ya. Kaplan, O.A. Shiryaeva. Determination of selenium in semiconductor compounds of type A3 B5 and in their components by the method of polarography with alternating current. Factory Laboratory No. 10, p. 1178, 1970 /. The disadvantage of these methods is that arsenic cannot be completely recovered by these methods.

The possibility of simultaneous sorption of arsenic, selenium and tellurium in combination with high capacity and selectivity provides a method of extraction on polymer thioether / 4. Shestakov V.A., Malofeeva G.I., Petrukhin O.M. et al. J. Analit. Chemistry, 1083, v. 38, No. 12, p. 2131. /. The high capacity and strength of the resulting complexes of the sorbent with PGM are due to the presence of sulfur atoms in the sorbent molecules. The bond of sorbed elements with sulfur atoms of the sorbent is so strong that desorption does not occur even in concentrated hydrochloric acid, which makes it possible to extract a number of elements from strongly acidic media. The disadvantage of thioether sorbents is the need for prolonged use of high temperatures (boiling), which is dangerous by the loss of recoverable elements due to the volatility of their compounds at elevated temperatures.

More effective for the extraction of selenium, tellurium and arsenic are aminothioether sorbents, which contain nitrogen and sulfur atoms simultaneously. In this case, sulfur provides the strength of the complex of the sorbent with the element, nitrogen contributes to the rapid establishment of coordination bonds. The high efficiency of these compounds is associated with a specific steric form of sorbent molecules / 5. M.V. Afonin, S.A. Simanova, N.M. Burmistrova, O.A. Shiryaeva, Yu.A. Karpov, Yu.S. Dalnova, N.S. Panin. Sorption extraction of chlorocomplexes of iridium (| II) and iridium (IV) with a new sulfur-nitrogen-containing sorbent. // Factory laboratory. Diagnostics of materials, No. 9, t. 74, p. 3, 2008 /. The advantage of the method is that in the absence of the need to use elevated temperatures, the sorption process proceeds at room temperature, which eliminates the risk of loss of elements due to volatility. The disadvantage of this method is the low sorption rate of the recoverable elements at low temperatures, which leads to an increase in the process time.

A known method of intensifying the sorption of an element on aminothioether sorbents without the use of elevated temperatures, by introducing iodide ions into solution / 6. Ivashchenko A.A., Dalnova Yu.S., Alekseev SV. et al. A method for intensifying the sorption process of noble metals on sorbents such as thioethers and aminothioethers. /

RF patent No. 2205239, 2003 /. The specified method is selected as the prototype of the claimed.

The essence of the known method is the introduction into the solution containing platinum, alkali metal iodides before applying the sorbent. The rate of sorption of platinum in this case increases and the completeness of extraction of the element is achieved in less time. It is known that iodide ion contributes to a greater efficiency of the action of aminothioether sorbents during the sorption of a number of other elements.

The disadvantage of this method is the undesirability of complicating the solution with an additional anion, which can interact with a wide range of elements present in leach solutions, with the formation of insoluble (for example, palladium iodide) compounds.

The technical result is a method of sorption extraction of selenium, tellurium and arsenic on aminothioether sorbents, devoid of this drawback.

The technical solution is the use of indium salts to intensify the process of sorption of selenium, tellurium and arsenic on aminothioether sorbents.

The essence of the method is the introduction of soluble indium compounds into the solution of recoverable elements before sorption. The number of indium compounds should exceed the amount of recoverable elements in the solution. At room temperature, a more rapid achievement of the complete extraction of these elements from the solution is observed. The use of indium in cationic form eliminates the possibility of unwanted interactions with the formation of insoluble compounds.

The effect of indium compounds on the sorption of elements by aminothioether sorbents is unknown.

The amount of indium required to achieve the claimed effect is in the range from 1 to 2 mass quantities in relation to the amount of recoverable elements. Below the lower limit, the effect is not sufficiently pronounced, and at indium concentrations above the upper limit, no additional amplification of the effect occurs.

The invention is illustrated by examples.

Example 1

In 200 ml of a 0.1 molar hydrochloric acid solution, 1 mg of selenium, 1 mg of tellurium, 1 mg of arsenic dissolved in mineral acids, 6 mg of indium in the form of hydrochloric acid were introduced, then 200 mg of an aminothioether sorbent of the formula C8 H16 N2 S4 was added at room temperature and kept under these conditions for 1 hour, sampling a solution of 1 ml every 15 minutes for analysis of selenium, tellurium, arsenic. The results are presented in table 1.

Example 2

In 200 ml of a 0.1 molar hydrochloric acid solution, 1 mg of selenium, 1 mg of tellurium, 1 mg of arsenic dissolved in mineral acids, 3 mg of indium in the form of hydrochloric acid were introduced, then 200 mg of an aminothioether sorbent of the formula C8 H16 N2 S4 was added at room temperature and kept under these conditions for 1 hour, sampling a solution of 1 ml every 15 minutes for analysis of selenium, tellurium, arsenic. The results are presented in table 1.

Example 3

In 200 ml of a 0.1 molar hydrochloric acid solution, 1 mg of selenium, 1 mg of tellurium, 1 mg of arsenic dissolved in mineral acids were introduced, then 200 mg of the aminothioether sorbent of the formula C8 H16 N2 S4 was added at room temperature and kept under these conditions for 1 hours, taking a sample of a solution of 1 ml every 15 minutes for analysis on selenium, tellurium, arsenic.

The results are presented in table 1.

Example 4

In 200 ml of a 0.1 molar hydrochloric acid solution, 1 mg of selenium, 1 mg of tellurium, 1 mg of arsenic dissolved in mineral acids, 100 mg of indium in the form of hydrochloric acid were added, then 200 mg of an aminothioether sorbent of the formula C8 H16 N2 S4 was added at room temperature and kept under these conditions for 1 hour, sampling a solution of 1 ml every 15 minutes for analysis of selenium, tellurium, arsenic. The results are presented in table 1.

The results of the experiments showed that the presence of indium in certain amounts increases the sorption rate of selenium, tellurium and arsenic on the aminothioether sorbent of the formula C8 H16 N2 S4. The effect is expressed if the amount of indium is equal to or exceeds the amount of recoverable elements by 2 times or more. When the indium content is less than the amount of the amount of recoverable metals, the effect is reduced. A significant excess of the content of indium over the content of recoverable metals does not have an additional increase in speed compared with a twofold excess.

Claims (1)

A method of sorption extraction of selenium, tellurium and arsenic from aqueous solutions, including sorption of recoverable elements on sorbents of the aminothioether type, the sorption being carried out using an intensifying agent, which uses water-soluble indium salts taken in an amount exceeding the amount of recovered elements by 2 times and more.