RU2394110C1 - Procedure for production of guanidine containing sorbents - Google Patents

Abstract

FIELD: metallurgy. ^ SUBSTANCE: procedure consists in dissolving poly-hexa-methylene-guanidine of hydrochloride in water solution of ammonia. Phenols and formalin by parts are poured to produced solution. Further solution is heated at boiling temperature during 1-5 h. Produced in total volume emulsion is poured out into water alkali solution. Also settled resin is washed from alkali and dried. ^ EFFECT: production of poly-hexa-methylene-guanidine insoluble in water. ^ 4 ex

Description

The method relates to the production of sorbents used to extract rare metals, in particular gold cyanide from aqueous alkaline solutions.

The method consists in conducting joint polycondensation of a water-soluble guanidine polymer with phenols and formaldehyde. The technical result of the method is to obtain a water-insoluble polymer with a high content of guanidine functions, expanding the range of sorbents with improved technological characteristics, expanding the sources of raw materials for their production.

A known method for producing guanidino-containing sorbents, which are obtained by introducing into the butadiene-styrene or divinyl styrene copolymer of guanidine function. First, the polymer is chloromethylated, for which an environmentally hazardous chloromethyl ether is used, which is obtained by the reaction of dimethoxymethane with thionyl chloride. The chloromethyl derivative is then aminated with guanidine, and no more than 5% of such functions can be introduced into the polymer [Pat. USA No. 3.346.516. Process for producing guanidine substituted cross-linked poly (vinylaromatic) anon exchange resins. Pat. USA No. 5.198.021. Recovery of precious metal. Pat. RU No. 2046628 С22В 3/00. A method of separating a precious metal from an alkaline aqueous solution of cyanide and an ion-exchange resin with guanidine functionality.

The closest in technical essence to the proposed invention is the method of RU 2046628.

The known method provides examples of the preparation of a guanidine-containing resin by sequential treatment of divinylbenzene with N-chloromethylphthalimide or chloromethylation of a styrene-divinylbenzene copolymer followed by reaction with methylcyanamide. The result is sorbents containing about 5% guanidine functionality.

The disadvantage of the method of producing sorbents based on butadiene styrene or divinyl styrene copolymer is the low content of active guanidine functional groups, the need to use hazardous substances that are hazardous to health and environmentally harmful.

The aim of the invention is to obtain a water-insoluble polyhexamethylene guanidine, expanding the raw material base for the synthesis of strongly basic guanidine-containing sorbents, simplifying the manufacturing technology, carrying out the synthesis of sorbents in environmentally friendly conditions.

This goal is achieved by the fact that, as a feedstock, a water-soluble, strongly basic polyhexamethylene guanidine polymer produced by the domestic industry is used (a water-insoluble polymer is not manufactured). Since this polymer is soluble in water (molecular weight up to 8 thousand carbon units), it is necessary to make it insoluble, that is, crosslink macromolecules and increase molecular weight. Polymer curing is carried out using phenols and formaldehyde. Common features of the proposed method and prototype are that polyhexamethylene guanidine is used as the starting polymer, that polyhexamethylene guanidine is treated with formaldehyde and phenols.

Distinctive features of the claimed invention from known methods for producing sorbents with guanidine functions are:

1. the use as a polymer base of low molecular weight polyhexamethylene guanidine;

2. the conversion of water-soluble polyhexamethylene guanidine to an insoluble polymer;

3. the water insolubility of polyhexamethylene guanidine is achieved inconsistent, and joint condensation with phenols in the presence of formaldehyde;

4. The condensation of polyhexamethylene guanidine with phenols and formaldehyde proceeds at boiling point for several hours, in the presence of ammonia.

These distinctive signs determine the achievement of the technical results of the claimed invention. The technical result of the claimed invention is to obtain a water-insoluble guanidine-containing polymer with a high content of guanidine functions and as a result with a high sorption capacity for metal. Another result of the invention is the expansion of the raw material base for producing guanidine sorbents, simplification of the technology for producing guanidine sorbents.

The proposed method is as follows. First polyhexamethylene guanidine hydrochloride is dissolved in an aqueous solution of ammonia, to which phenols are added. Formalin is poured in parts to the resulting solution and additionally heated to boiling for 1-5 hours, the emulsion formed throughout the volume is poured into an aqueous alkaline solution, the precipitated resin is washed from alkali and dried.

The method is confirmed by specific examples.

Example 1

17.7 g (0.1 mol) of polyhexamethylene guanidine hydrochloride was dissolved in 50 ml of aqueous ammonia, 5 g (0.05 mol) of phenol was added to the solution, and then 20 ml of formalin solution was poured in parts and boiled for 5 hours. The turbid reaction mixture was poured. in aqueous alkali 1N, pink resin is deposited, which, when kept in water, swells and becomes very pale. After drying at 50 ° C (weight 20.3 g), the resin becomes elastic, rubber-like, dissolves in acetic acid.

Example 2

When heated, 17.7 g (0.1 mol) of polyhexamethylene guanidine hydrochloride is dissolved in 20 ml of aqueous ammonia, then 9.4 g (0.1 mol) of phenol is added, and 20 ml (30%) of formalin are poured in part to the resulting solution. After 30 minutes of boiling, at first the clear solution becomes cloudy, after additional boiling for 1 hour, the reaction mixture is poured into 1N cold aqueous alkali. The precipitated resin is washed with water, dried without heating. The output is quantitative. It turns out a resin soluble in isopropanol and acetic acid. Solid dry resin swells when kept in water by 60%, after drying at 100 ° C it becomes insoluble in benzene, toluene, acetone, isopropanol, ethylene glycol, hexane. The IR spectrum of the modified resin (strong bands at 1643, 1474, 1277, as well as at 1355, 1149 and a number of strips in the region of 827-610 cm ^-1 ) differs significantly from the spectrum of the initial polyhexamethylene guanidine hydrochloride (strong hump at 1635 cm ^-1 , and humps at 1464, 1351, 1100 and 561 cm ^-1 ).

Example 3

22 g (0.1 mol) of polyhexamethylene guanidine hydrochloride and 10.8 g (0.1 mol) of para-cresol are dissolved in a mixture of 50 ml of ammonia and 10 ml of isopropanol. To the solution, 40 ml of an aqueous solution of formaldehyde are added in portions. The mixture is additionally boiled for 4 hours. The reaction mixture is cooled, 100 ml of 10% alkaline solution and 10 g of sodium chloride are added. The thickened resin is washed with cold water, dried at 50 ° C, yield 29 g.

Example 4

The resin obtained by method 3 is used for sorption of gold cyanide at a pH of 10.5. 0.1 g of resin is poured into 100 ml of gold cyanide containing 80 mg / l of metal, and stirred on a magnetic stirrer for one day. The residual gold content in the solution is 0.1 mg / L.

Claims (1)

The method of producing guanidine-containing sorbents for gold extraction, which consists in dissolving polyhexamethylene guanidine hydrochloride in an aqueous ammonia solution, adding phenols to the resulting solution, formalin is added in part and heated at the boiling point for 1-5 hours, the emulsion formed throughout the volume is poured into aqueous alkaline solution, the precipitated resin is washed from alkali and dried.