RU2746213C2 - Method of extraction of microelements from highly mineralized water - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to extraction of iodine and bromine. Method of extracting iodide- and bromide-ions from formation water of oil deposits includes use of sorbents with subsequent desorption by desorbent solution. Sorbents used are anionites AN-31 or AN-2FN, the desorbent used is a solution of manganese chloride and sodium chloride.EFFECT: disclosed method provides extraction of iodide ions and bromide ions pre-sorbed from formation water of oil deposits on anionites, with reduction of number of stages and increase in efficiency of extraction of valuable microelements, using cheaper reagents for extraction of halogenides from anionites.1 cl, 3 tbl

Description

The field of technology . The invention relates to a technology for the extraction of iodine and bromine after their sorption from formation waters by anion exchangers and can be used to obtain iodine and bromine.

State of the art.

The invention relates to the field of processing waste products from the oil industry, namely, applicable to stratal waters. The technology makes it possible to extract valuable halogens sorbed on anion exchangers from reservoir waters of oil fields.

A known method of extracting iodine and bromine from acidic solutions containing iodide, bromide and chloride ions, using ion exchangers, including the sorption of iodine on one load of ion exchanger, oxidation of bromide ions to elemental bromine and sorption of bromine on another load of ion exchanger, desorption of iodine and bromine, the regeneration and return of both loads of the ion exchanger for sorption, the sorption of iodine is carried out in the form of iodide ions by a part of the load of the ion exchanger saturated with elemental bromine. The disadvantage of this method is a decrease in the extraction efficiency due to a decrease in the sorption rate with a decrease in the concentration of the extracted sorbate. (RF patent No. 2094379, 1997) http://www.findpatent.ru/patent/232/2325469.html/

The closest analogue is a method for extracting iodine and bromine from natural waters / RF Patent No. 2190700, C25B 1/24, C02F 1/461, 2002 /. First, selective electrochemical oxidation of iodide is carried out in the anode chamber of a diaphragm electrolyzer in the presence of Fe ^{2+ ions} at a redox potential of the anionite of 550-850 mV. After that, it is treated with an alkaline agent, co-precipitating iodine on iron (III) hydroxide. Then, selective electrochemical oxidation of bromide is carried out in iodine-free water, followed by its release by air desorption. The treatment of the anion exchanger with an alkaline agent is carried out in the pH range 3.5-5.0. Hydroxides or carbonates of alkali or alkaline earth metals are used as an alkaline agent. The disadvantage of this method is a decrease in the extraction efficiency due to a decrease in the sorption rate with a decrease in the concentration of the extracted sorbate.

The closest technical solution to the proposed invention is a method for extracting iodine from solutions / RF Patent No. 2207976, С01В 7/14, 2003 /, which consists in the fact that a brine with an iodine content of 35 g / m ^{3 is} oxidized to elemental iodine, sorbed on a weakly basic synthetic anion exchanger. An anion exchanger is used, which has a matrix based on a copolymer of acrylic acid nitrile and divinylbenzene, and functional groups - primary amines (50%), secondary amines (20%), tertiary aromatic amine of the imidazoline type (30%). Free halogens are isolated by desorption of iodine with a NaOH solution. The concentration of iodine in the desorbate in a continuous counter-flow regime is 294 g / l. The invention also makes it possible to reduce the consumption of reagents, the volume of equipment, labor and energy costs, and reduce the wear of the resin. The disadvantage of this method is the lack of the possibility of highly efficient extraction of iodine.http: //bd.patent.su/2207000-2207999/pat/servl/servlet1702.html/

The technical result is the development of a method for the extraction of iodide ions and bromide ions, previously sorbed from the formation waters of oil fields on anion exchangers, which will reduce the damage to oil refining, reduce the number of stages, increase the efficiency of extraction of valuable trace elements, and also allow the use of cheaper reagents for the extraction of halides from anionites.

The method is carried out as follows.

Solutions of manganese chloride with sodium chloride were used as a desorbent for the extraction of trace elements from anionites. For the sorption of halides, anionites of two grades were used - AN-31 and AN-2FN.

Sorption of iodide and bromide ions was carried out under dynamic conditions by passing formation waters through a column filled with anion exchangers until the anion exchangers were saturated with iodine and bromine.

After saturation, the anionites from each column after sorption were subjected to desorption of iodide and bromide ions with a solution of divalent manganese chloride 75 g / l and sodium chloride 150 g / l. Desorption was carried out under dynamic conditions by passing a desorbent solution through the column until a negative reaction at the exit from the column for iodide and bromide ions.

In the process of desorption of iodide and bromide ions with a solution of sodium chloride, in the presence of divalent manganese ions, the following reactions occur:

R (J ₂ Cl) + Mn ²⁺ + H ₂ O = R (J + MnO ₂ ) + HCl + HJ + 2H ⁺

R (J + MnO ₂ ) + NaCl = R (Cl + MnO ₂ ) + NaJ

Desorption of bromide ions will proceed similarly. Elemental iodine and bromine oxidize divalent manganese ions directly in the ion exchanger phase to manganese dioxide, which also precipitates in the ion exchanger phase, and iodide and bromide ions are released into the solution.

The results of the desorption of halogens by solutions with different ratios of manganese and sodium chlorides showed that the degree of extraction of trace elements for two grades of anion exchangers (AN-31 and AN-2FN) in the ratio of the concentration of manganese chloride 75 g / l and sodium chloride 150 g / l is the highest and is 95 , 0 ± 3% (Table 1).

Table 1

The degree of extraction of trace elements using desorbent MnCl ₂ , / NaCl

Anionites Jonah Concentration ratio
MnCl ₂ , / NaCl, g / l 50/100 75/150 100/200 AN-31 I ^- 81.0 98.5 98.0 Br ^- 75.5 95.0 95.0 AN-2FN I ^- 78.5 91.0 90.0 Br ^- 83.0 93.5 94.0

The kinetics of the desorption of iodide ions on ion-exchange resins AN-31 and AN-2FN with a solution of divalent manganese chloride 75 g / l and sodium chloride 150 g / l are presented in Table 2.

table 2

Kinetics of the process of desorption of iodide ions on anion exchangers with a solution of MnCl ₂ and NaCl

Anionites Desorption time, min twenty 40 60 80 100 Recovery rate (S),% AN-31 thirty 60 70 98 98 AN-2FN 10 thirty 60 90 91

The results of the study showed that with an increase in the contact time of the desorbent with anion exchangers, the degree of extraction of iodide ions increases and reaches a maximum value of 98% after 80 minutes of the experiment for the grade of anionite AN-31, for the anionite AN-2FN the degree of extraction of iodide ion reaches 90% after 80 minutes of the experiment. A further increase in the contact time does not lead to a significant increase in the degree of extraction of iodides from anionites. The optimal time for the complete extraction of the iodide ion from the anion exchangers is 80 minutes for two grades of sorbent.

Table 3

Kinetics of the process of desorption of bromide ions on anion exchangers with a solution of MnCl ₂ and NaCl

Anionites Desorption time, min twenty 40 60 80 100 Recovery rate (S),% AN-31 thirty fifty 70 90 91 AN-2FN twenty 45 60 94 94

The study of the kinetic characteristics of desorption of bromide ions from anionites showed that the optimal desorption time, as well as for iodide ions, is 80 minutes and the degree of extraction reaches 91% for anionite grade AN-31 and 94% for grade AN-2FN. It should be noted that the desorption of bromide ions with a solution of MnCl ₂ and NaCl proceeds better in the phase of the anionite grade AN-2FN.

Claims (1)

A method for extracting iodide and bromide ions from reservoir waters of oil fields, including the use of sorbents followed by desorption with a desorbent solution, characterized in that anionites AN-31 or AN-2FN are used as sorbents, a solution of manganese chloride and sodium chloride is used as a desorbent ...