RU2256496C1 - Sorbent, method for preparation thereof, and a method for separately recovering metal salts from wastes - Google Patents

Abstract

FIELD: sorption technologies.

SUBSTANCE: invention aims at preparing carbon sorbent for recovering valuables components from various production wastes. Proposed sorbent has summary water-accessible pore volume 0.2-0.3 cm³/g, specific surface 60.0-80.0 m²/g, iodine sorption activity 35.0-45.0%, benzene sorption activity 3000.0-330.0 mg/g, ash residue 45.0-47.9%, and loosed density 0.28-0.30 kg/dm³. Preparation of sorbent comprises treating peat with potassium hydroxide, separating solid and liquid phases, treating the latter with acid reagent to lower pH to 4.0-6.0 thereby obtaining gel-like precipitate and supernatant, multistage treatment of supernatant with acid reagent to lower pH to 2.0-2.5 and thereby to separate gel-like precipitates and supernatants in each stage, heat treatment of gel-like precipitates, mixing them with each other and with solid phase, carbonization of resulting product, granulation and mixing of granules with previously obtained gel-like precipitate with pH 2.0-2.5 and subsequent aeration at elevated temperature. In the proposed method of recovering metal salts from wastes, waste is ground and leached with solution containing fulvene acids followed by sorbent-assisted chromatographic fractionation and recovery of corresponding metal salts. After separation of solid and liquid phases, the latter is passed through sorbent, which is further regenerated with sulfuric acid solution. Solid phase is fractioned via multistage treatment with fulvene acids-containing eluent solution, while raising pH of solution in each stage. Eluates from each stage are separately brought into contact with sorbent, which is further regenerated with sulfuric acid solution.

EFFECT: facilitated recovery of valuable waste components.

7 cl, 2 tbl, 3 ex

Description

The invention relates to sorption technologies and can be used to obtain a carbon sorbent and its further application for the extraction of valuable components from waste from various industries.

Known ion-exchange materials used to separate various ions of heavy and non-ferrous metals, which are ion-exchange resins of both porous and gel structures (see, for example, “Ion-exchange materials for hydrometallurgy, wastewater treatment and water treatment”, catalog under the editorship of B .N. Laskorina. M., VNIIHT, 1980).

Among the known materials, it is possible to select highly selective sorbents that provide a high separation coefficient of specific ions at a high capacity.

However, the materials described are quite expensive.

Also known are carbon sorbents used for the separation and separation of metal ions (see, for example, V.M. Mukhin and other Active carbons of Russia. M., 2000, pp. 262-271).

Closest to the proposed one is a sorbent based on mesoporous carbon, which can be used for the separation of heavy and non-ferrous metal ions, described in the mentioned book (see V.M. Mukhin and other Active carbons of Russia. M., 2000, p. 314 -319).

There are also known methods for producing carbon sorbents, involving the carbonization and activation of natural raw materials, and in particular peat (see V.M. Mukhin and other Active carbons of Russia. M., 2000, p. 254).

Closest to the proposed one is a method for producing a carbon sorbent, which includes treating peat with a potassium hydroxide solution, separating solid and liquid phases, lowering the pH of the liquid phase to 4-6 to obtain a gel containing immobilized humic acid (AT 382326, B 01 J 20/24, 1987).

However, the resulting sorbent has a low hydromechanical strength.

Numerous methods are known for processing production wastes containing valuable metals, which are based on leaching of raw materials and subsequent sorption separation of valuable components and their separation (see, for example, RU 2067125, 1996; RU 2118384, 1998; RU 2069180, 1996).

In known methods, acids are used to isolate valuable components, which creates a problem of secondary waste, and ion separation resins are mainly used to separate components, which makes the process more expensive.

Known methods of processing metal-containing materials that use different types of activation to increase the degree of opening of raw materials and to intensify the process, for example, mechanical activation (RU 2095438, 1997), or electrical exposure, which leads to the appearance of ultraviolet, X-ray, optical radiation (see RU 2082079, 1997 ; RU 2082780, 1997; AT 659359, 1994; RU 2198941, 2003).

The closest in technical essence to the proposed method for the separate separation of metal salts from waste is a waste processing method, according to which waste containing various metals is subjected to grinding, leaching, chromatographic fractionation of the leach product to obtain individual metal salts.

For example, during the processing of concentrates containing noble metals, after acid oxidative leaching, the gold fraction is separated chromatographically from the liquid phase, and the remaining liquid is chromatographed fractionally into individual metals of the platinum group (RU 2213793, 10.10.2003).

The known method is expensive, because for its implementation use expensive commodity reagents.

The objective of the present invention is to obtain a mechanically durable sorbent capable of providing a high degree of extraction of metal salts from production wastes and their separation into individual components using intermediate products of the process of obtaining the used sorbent, i.e. in fact, to develop a waste-free integrated technology for producing high-quality carbon sorbent and its use.

The problem is solved by the described sorbent based on mesoporous carbon for the separation of ions of heavy and non-ferrous metals, which has the following characteristics:

the total pore volume of N ₂ About - (0.2-0.3) cm ³ / g;

specific surface - (60.0-80.0) m ² / g

iodine sorption activity - (35.0-45.0)%

benzene sorption activity - (300.0-330.0) mg / g

ash content - (45.0-47.0)%

bulk weight - (0.28-0.30) kg / dm ³

The problem is also solved by the method of producing a sorbent with the above characteristics, which consists in the fact that peat is treated with a potassium hydroxide solution, the solid and liquid phases are separated, the liquid phase is subjected to interaction with an acidic reagent, providing a decrease in pH to 4.0-6.0 s obtaining a gel-like precipitate and a supernatant, after which the supernatant is treated with an acidic reagent in several stages, providing a decrease in pH to 2.0-2.5 with separation of gel-like precipitates at each stage and admixture liquids, while separately collecting gel-like precipitates and part of the supernatant liquids from each subsequent gelation stage, while separately collected gel-like precipitates are heat treated in air at 110-120 ° C, the heat-treatment products are mixed with each other and the solid phase separated after peat treatment with potassium hydroxide solution , the product of mixing is subjected to carbonization, activation and granulation, the obtained granules are mixed with the previously obtained gel-like precipitate with a pH of 2.0-2.5, washed with water, until the granules are coated enkoy gel and subjected to aeration at an elevated temperature.

The problem is also solved by the described method of separate separation of metal salts from wastes, including their grinding, leaching, chromatographic fractionation using a sorbent and the separation of salts of the corresponding metals, leaching is carried out with a solution containing fulvic acids, the solid and liquid phases are separated, the liquid phase is passed through a sorbent, which described above, followed by regeneration of the sorbent with a solution of sulfuric acid, and the solid phase is subjected to fractionation by its many a stage-by-stage treatment with an eluent solution containing fulvic acids with increasing pH of the solution at each stage, after which the eluates of each stage are separately contacted with the sorbent, the characteristics of which are given above, followed by regeneration of the sorbent with a solution of sulfuric acid.

The method is characterized in that supernatants of different stages of gelation of the process for producing the used sorbent, which is described above, having previously determined their affinity for a specific metal ion, are used as eluent.

To increase the efficiency of the process, the contacting of the solid phase with the eluent is carried out when the activating effect is applied in the form of an electric, electromagnetic, magnetic or thermal field, or before the solid phase is contacted with the eluent, the latter is subjected to the activating effect of an electric, electromagnetic, magnetic or thermal field.

The method involves the use of slag and sludge from metallurgical and galvanic industries as recyclable waste.

Example 1 (the implementation of the method of producing the sorbent).

The lowland peat of the Melchevsky field is used, which is treated with a 0.5% potassium hydroxide solution. The solid and liquid phases are separated, after which the latter is treated with hydrochloric acid, lowering the pH in several stages, with a pH step of 2.0. Gel-like precipitates from each gelation stage are subjected to heat treatment for 14 hours with an air stream at 110-120 ° C, and the products obtained are mixed with the solid phase obtained after processing lowland peat with a potassium hydroxide solution. The mixture is carbonized at 550-600 ° C and held at a final temperature for 30 minutes. After that, it is cooled and activated with water vapor at 830-850 ° C. After the granulation process of the mixture, the granules are mixed with a gel-like precipitate of the second gelation stage, previously washed with water, to obtain a sorbent, and drying is carried out in a stream of air at a temperature of 60 ° C. The resulting sorbent has, for example, the following characteristics:

Table 1 No. Name of indicators, units measuring 1 Humidity% 0,0 2 Ash content,% 46.91 3 Granulometer composition, % 5 mm 9.55 3 mm 70.41 1 mm 16,48 0.4 mm 0.84 4 Bulk weight, kg / dm ³ 0.295 5 Durability on attir.,% 76.7 6 Specific capacity, m ² / g 69.70 7 pH 7.0 8 Sorption activity for iodine,% 41.34 nine Sorption activity for benzene, mg / g 319.50 10 The total pore volume in water, cm ³ / g 0.24

In this way, granules are obtained, both identical and different in geometric dimensions, as well as geometrically similar. The granule sections correspond to a number of second-order curves. Obtaining granules of various types expands the scope of application of the sorbent created by the proposed method.

The use of this sorbent, which has increased strength characteristics, increased values of sorption capacities, as well as the ability to function in various solutions, allows for the efficient purification of solutions and waters of heavy metals and organic impurities.

Example 2 (the implementation of the method of extracting metals from sludge).

Grind 1 kg of sludge from the Kolomna Engineering Plant, the composition of which is given in table 2.

table 2 p / p Name of ingredients Source result Final result 1 2 3 1 The reaction medium, unit pH 7.1 2 Density, kg / m 1410 3 Full humidity. % 86.0 4 Hygroscopic humidity. % 6.53 5 Insoluble residue (SiO ₂ , Al ₂ O ₃ and - 6 Chlorides. mg / kg 1043 7 Sulphates. mg / kg 4919 8 Petroleum products, mg / kg abs. dry 623 nine Ammonium nitrogen, mg / kg 318 10 Stranded, mg / kg 437 16 eleven Zinc mg / kg 744 81 12 Nickel, mg / kg 295 45 thirteen Manganese, mg / kg - 14 Iron total., Mg / kg 4039 100 fifteen Chromium mg / kg 264 twenty 16 Phosphates (phosphorus), mg / kg 19

Collect the supernatants obtained after the first and second gelation stages upon receipt of the sorbent (see example 1). The amount of mixture obtained over sedimentary liquids was 0.5 kg. The slurry is mixed with a mixture of supernatants with a pH of 5.0 to obtain pulp at a temperature of 50 ° C. The mixing time is 3 hours. In this case, chromium, iron and nickel ions are leached with the formation of the corresponding salts. After separation of the pulp into solid and liquid phase, the latter is passed through the sorbent obtained in example 1. The loaded sorbent is regenerated with a 5% solution of sulfuric acid to obtain sulfates of the corresponding metals. As a result, water-soluble forms of metals contained in the original sludge are removed.

After this, a chemical analysis of the solid phase obtained after separation of the pulp is carried out, and the presence and content of insoluble metal compounds (nickel, copper) are determined. The solid phase is sequentially treated with the appropriate supernatant of different stages of gelation (for nickel, pH 4, for copper, pH 2) at a temperature of 50 ° C for 2 hours, and the ratio T: W = 1: 10. After that, the mixture is divided into solid and liquid phases and the liquid phase is passed through the previously obtained sorbent. The loaded sorbent is regenerated with a 5% solution of sulfuric acid to obtain sulfates of the corresponding metals (iron, copper, nickel, chromium, etc.)

Example 3. Grind 1 kg of sludge from the Kolomna Engineering Plant, the composition of which is shown in table 2. Collect the supernatants obtained after the first and second gelation stages upon receipt of the sorbent (see example 1). The amount of the resulting mixture of supernatants was 0.5 kg. The slurry is mixed with a mixture of supernatants with a pH of 5.0 to obtain pulp at a temperature of 50 ° C. The mixing time is 3 hours. In this case, chromium, iron and nickel ions are leached with the formation of the corresponding salts. After separation of the pulp into solid and liquid phase, the latter is passed through the sorbent obtained in example 1. The loaded sorbent is regenerated with a 5% solution of sulfuric acid to obtain sulfates of the corresponding metals. As a result, water-soluble forms of metals contained in the original sludge are removed.

After this, a chemical analysis of the solid phase obtained after separation of the pulp is carried out, and the presence and content of insoluble metal compounds (nickel, copper) are determined. The solid phase is sequentially treated with the appropriate supernatant of different stages of gelation (for nickel, pH 4, for copper, pH 2) at a ratio of T: W = 1: 10, during the processing the activating action of a magnetic field with a strength of 1 ke is carried out. After that, the mixture is divided into solid and liquid phases and the liquid phase is passed through the previously obtained sorbent. The loaded sorbent is regenerated with a 5% solution of sulfuric acid to obtain sulfates of the corresponding metals (iron, copper, nickel, chromium, etc.). The result of the magnetic field (with the same final results obtained in example 2) is a decrease in the flow rate of used supernatants, which ultimately reduces the cost of the process.

Similarly, separate separation of metal salts from slags and sludges was carried out when using electric and electromagnetic fields as an activating effect. The research results showed that the activating effect in the form of electric, magnetic, electromagnetic and thermal fields, carried out both in the process of contacting the solid phase with the eluent, and before contacting, allows to increase the degree of elution of valuable components.

Claims (7)

1. Sorbent based on mesoporous carbon for the separation of ions of heavy and non-ferrous metals, characterized in that it has the following characteristics: The total pore volume in N ₂ About (0.2-0.3) cm ³ / g Specific surface (60.0-80.0) m ² / g Sorption activity for iodine (35.0-45.0)% Sorption activity for benzene (300.0-330.0) mg / g Ash content (45.0-47.0)% Bulk weight (0.28-0.30) kg / dm ³ 2. The method of obtaining the sorbent described in claim 1, which consists in the fact that peat is treated with a solution of potassium hydroxide, the solid and liquid phases are separated, the liquid phase is subjected to interaction with an acidic reagent, providing a decrease in pH to 4.0-6.0 s obtaining a gel-like precipitate and supernatant, characterized in that the supernatant is treated with an acidic reagent in several stages, providing a decrease in pH to 2.0-2.5 with separation at each stage of gel-like precipitates and supernatants, while collecting separately gelled precipitates and part of the supernatant liquids from each subsequent gelation stage, moreover, separately collected gelled precipitates are heat treated in air at 110-120 ° C, the heat-treated products are mixed with each other and the solid phase separated after the peat is treated with potassium hydroxide solution, the mixing product is subjected to carbonization, activation and granulation, the obtained granules are mixed with the previously obtained gel-like precipitate with a pH of 2.0-2.5, washed with water, until the granules are coated with a gel film and aerated at elevated temperature. 3. The method of separate separation of metal salts from waste, including grinding, leaching, chromatographic fractionation using a sorbent and the separation of salts of the corresponding metals, characterized in that the leaching is carried out with a solution containing fulvic acids, the solid and liquid phases are separated, the liquid phase is passed through the sorbent, characterized in paragraph 1, followed by regeneration of the sorbent with a solution of sulfuric acid, and the solid phase is subjected to fractionation by multistage processing of the solution m of an eluent containing fulvic acids with increasing pH of the solution at each stage, after which the eluates of each stage are separately contacted with the sorbent described in paragraph 1, followed by regeneration of the sorbent with a solution of sulfuric acid. 4. The method according to claim 3, characterized in that part of the supernatant liquids of different stages of gelation of the process for producing the used sorbent, described in claim 2, having previously determined their affinity for a particular metal ion, is used as an eluent. 5. The method according to claim 3, characterized in that the contacting of the solid phase with the eluent is carried out by applying an activating effect in the form of an electric, electromagnetic, magnetic or thermal field. 6. The method according to claim 3, characterized in that before contacting the solid phase with the eluent, the latter is subjected to an activating effect of an electric, electromagnetic, magnetic or thermal field. 7. The method according to claim 3, characterized in that the waste used is slag and sludge from metallurgical and galvanic industries.