Method of producing high strength and capacity carbon sorbent

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a carbon sorbent used for extracting rare metals, particularly gold cyanide from aqueous alkaline solutions. The method involves treatment of activated carbon with a polymer with amino groups. Activated charcoal is treated using polyhexamethylene guanidine hydrochloride in form of an aqueous solution. After treatment, alkali is added while stirring and the solution is separated from the carbon. The carbon is saturated with ammonia solution, phenol and formalin. The mixture is held while boiling for 1-5 hours and the carbon separated from the solution is dried at 150-160°C.

EFFECT: obtaining a carbon composition with high strength and anion-exchange capacity from readily available and cheap charcoal.

1 tbl, 5 ex

 

The method relates to the production of coal sorbents used for water purification and extraction of anions, including the complex of gold cyanide from aqueous alkaline solutions.

The use of activated carbon for water purification from metal ions and organic impurities has long been known and is widely used in technological practice, including for the extraction of complex cyanide of gold [Wastler, Majorityof. Metallurgy of noble metals. - M.: the MMA, 2002, s]. A significant drawback of coal sorbents is their low mechanical strength, which is about 60% [GOST 6217-74] for coal varieties BAU and 94-96% for charcoal made from coconut shell. Thus the capacity of the activated carbon is 0.2-0.3 g-EQ/kg

Modification of carbon materials by application of complexing agents known as adsorption-kompleksoobrazovateleyj method for the separation and concentration of ions [ed. mon. The USSR # 99924]. Application of sorbents can increase porosity, increase the selectivity of [U.S. Pat. Of the Russian Federation No. 2172209, 2288514, 2393111], to enhance the frictional characteristics of the coal compositions [U.S. Pat. U.S. No. 5952447]. The method used for preconcentration of metal ions [Sov. The influence of some complexing agents for the quantitative determination of ions of Cu2+IU the Odom solid-phase spectrophotometry. // Scientific Bulletin of Dinner. Series chemistry. 2010. VIP. S-138. Pat. Of the Russian Federation No. 2104778].

Activated carbon effectively adsorb organic substances, in particular phenol from aqueous solutions [Liiiive, Wowturkey, Down, Vouchering. Adsorption of phenol // SibFU. 2009, №1, s-32]. In the presence of formaldehyde on its surface is formed phenol-formaldehyde resin, which changes the physico-chemical characteristics of the coal. This method of modification of physico-chemical properties of the carbon porous materials using impregnator, consisting of a solution of shale phenols, furfural and polyethylenepolyamines, implemented in [Yevdokimova, Lietuviska. // Oil shale industry, 1986, No. 1, p.18-21].

This way the technical nature of the close of the present invention and may serve as a prototype. Modificate the surface of the coal, apparently, is as follows:

As a result of adsorption of the reactants on the surface of coal and their subsequent reactions with formaldehyde formed methylol and imine groups.

Object of the invention is the production of carbon sorbents with high sorption efficiency and increased abrasion resistance.

This task is achieved by the fact that the quality of raw materials used cheap charcoal and imp is egnater, consisting of phenol, formaldehyde, guanidine (metacid).

The method consists in the application of guanidine on the surface of the charcoal brand BAU-A. Because metacid easily washed off with water, so they conduct curing it with the participation of phenol and formalin. The technical result of this method is the production of carbon sorbent with improved physico-chemical characteristics, in particular high strength and capacity.

The General features of the proposed method and the prototype are, first, that as a sorbent carbon material is used, secondly, coal integriruetsa polymer containing amino groups.

The hallmark of the claimed invention from the known method is the absence of annealing of the modified carbon material, anchoring polymer phase coal joint polycondensation with phenol and formaldehide.

Such processing of coal provides increased strength and reduced abrasion, and high and stable sorption capacity due to the presence of coal composition guanidino functional groups, sewn into the polymer matrix.

High specific surface area and porosity of coal provide good kinetic sorption characteristics unattainable for compact copolymer metacid, pheno is a and formaldehyde.

Schematically the structure of the modified coal can be represented as follows:

The technical result of the invention is the production of carbon composition of high strength and anion-exchange capacity of the available and inexpensive charcoal.

The proposed method consists in the following. First dissolve polyhexamethylene guanidine hydrochloride in hot water, then poured into a solution activated carbon. To the mixture under vigorous stirring portions add an aqueous solution of alkali. When this polymer is planted in the form of a thin suspension and is adsorbed by the charcoal. The aqueous phase is drained, and the coal is poured ammonia solution. In ammonia solution is poured phenol and formaldehyde. The mixture is boiled for 1-5 h and filtered. The coal is washed with an alkaline solution and finally with cold water until neutral pH, dried. The method is confirmed by specific examples. Properties of the modified samples of coals in the table.

Strength tests of modified coal (Aug) according to GOST 6217-74 and the exchange capacity of the anion Cl-
№ p/pThe type of coalRelative strength, %/td> Full exchange capacity, mEq/g
1Coal BAU-a60of 0.2-0.3
2Coconut charcoal940,3
3Aug-1850,42
4Aug-2890,52
5Aug-3970,97
6Aug-4980,98
7AGU-5991,00

Example 1.

16 g (0.1 mol) of polyhexamethylene guanidine hydrochloride when heated, dissolved in 150 ml of water, then add 20 g of activated charcoal, 6 g of phenol in 20 ml of ISO-propanol. To the mixture in parts poured 20 ml of ammonia, 10 ml (40%) of formalin and boiled for 5 hours the Aqueous solution is filtered, the coal is washed with water, dried at tcomm Weight 25 g of Sample Aug-1. Strength n the abrasion (according to GOST 6217-74) and total capacity shown in the table.

Example 2.

16 g (0.1 mol) of polyhexamethylene guanidine hydrochloride when heated, dissolved in 200 ml of water, in aqueous solution pour 20 g of activated charcoal and cooled to tconn In a container with stirring, add 6 g of phenol in 20 ml of ISO-propanol and 20 ml of aqueous ammonia. To the resulting mixture is poured 20 ml (40%) of formalin and boiled for 1 h Aqueous solution is separated by decantation, the coal is washed with water, dried at 100°C. the Weight 26 g (Aug-2). Abrasion (according to GOST 6217-74) and total capacity shown in the table.

Example 3.

16 g (0,097 mol) polyhexamethylene guanidine hydrochloride are dissolved in 200 ml of water at boiling. In the solution, pour 20 g of activated charcoal, cooled to tconn and stirred for 1 h and Then in parts poured 100 ml of 10% alkali under vigorous stirring, with polyhexamethylene guanidine planted in the form of a thin slurry and sorbed on charcoal, the solution is clarified.

The aqueous alkaline solution is separated by decantation. Coal add 200 ml of water with 40 ml of aqueous ammonia. In parts poured 5.6 g (0,06 mole) of phenol, stirred 1 h, then add 20 ml (40%) of formalin and boil 3 hours After cooling, the aqueous solution is drained, washed coal 10% alkali, then with water until neutral pH, dried, calcined at 150° C. Yield 24.5 g (Aug-3).

Example 4.

In the same way as in example 3, except that the polycondensation is avodat in ammoniacal solution of polyhexamethylene guanidine hydrochloride in the presence of 4 g (0,04 mole) of phenol and 10 ml of formalin, in for 1 hour under vigorous stirring. After cooling the charcoal is filtered for the removal of phenol was washed with an alkaline solution, then with water until neutral, dried, annealed at 160°C. the Output of coal sorbent of 29.3 g (Aug-4).

Example 5.

In the same way as in example 3, but instead of charcoal used coconut charcoal. Processing is similar to example 4. AGU-5 (see table).

The method of obtaining carbon sorbent, including the processing of activated carbon polymer with amino groups, wherein the treatment machine wood activated carbon with the use of the polymer of guanidine hydrochloride in aqueous solution followed by the addition of alkali under stirring and separation of the solution from the coal, and after the aforementioned processing, the coal is poured ammonia solution, phenol and formalin, the mixture was kept at boiling for 1-5 h, then separated from the solution, the coal is dried at 150-160°C.



 

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