Process for producing mineral-carbonic adsorbents

Description:

The invention relates to processes for obtaining mineral-carbon adsorbents and can be used for wastewater treatment of organic compounds.

The process of obtaining the mineral-carbonic adsorbent, which includes thermal processing and carbonization of bentonite and yeast sediments from vinification in a non-oxidizing atmosphere, is subsequently known to modify their surface [1]. This process includes the use of ferrocyanide-containing wastes, which reduces the ecological safety of their production due to the release of free cyanide and does not ensure sufficient efficiency of the adsorbent obtained due to the reduced sorption and selection capacity.

The closest solution is the process of obtaining the mineral-organic adsorbent for wastewater treatment which includes the thermal processing of expanded pearl waste until their carbonization [2]. In addition, the electrochemical activation of the adsorbent and its surface modification in orthophosphate of alkaline metals is performed. however, the efficiency of using this adsorbent is low due to the reduced sorbent characteristics in the wastewater treatment processes with many components.

The problem solved by the invention was to improve the sorbent characteristics and increase the mechanical hardness of the adsorbent for wastewater treatment, as well as to increase the base of raw materials due to the use of production waste.

The essence of the invention is that the mixing of 60 ... 80% mas is carried out. of expanded perlite waste from the processes of filtration of wine raw material and 20 ... 40% mas. of flotoslam, obtained by electroflotation after the solubilization of the Berlin blue from the sticky wine precipitates, after which the mixture is dried up to the remaining humidity of 7% and the heat treatment under isothermal conditions at о temperature of 400 ... 500 ° C for 0, 5 to 1 hours.

The result consists in increasing the efficiency of waste water treatment due to the improvement of the sorption capacity of the adsorbent used, obtained from production waste, as well as to the improvement of the mechanical hardness of its particles by forming on the macro-, meso- and micropores of the mineral structure of pearlite and bentonite. uniform carbon layer with properties of activated carbon.

The advantages of the adsorbent obtained compared to the known ones are:

• Increased dynamic sorption capacity after surfactant compounds of 1.1 ... 1.4 times, of the specific surface of 1.15 ... 1.32 times and of the summary volume of the pores of 1.1 ... 1, 4 times, which increases the efficiency of the wastewater treatment process.

• Increased mechanical hardness by 1.12 ... 1.2 times, which improves the operating characteristics of the adsorbent.

• Enlargement of the raw material base for the production of adsorbents due to the use of waste from vinification.

• The possibility of using the adsorbent for the complete cleaning of waste water from enterprises and their reuse in a closed cycle.

Sediments containing pearlite, obtained from the filtration of wine and juices, represent particles with a dispersion of 1 ... 2 mm. The pearlite is a natural material, which is subjected to special chemical-thermal processing in order to open the pores and increase the sorption properties. Pearl is a very expensive product. After the wine is filtered, the remaining sediments containing up to 50 ... 80% mass of organic substances - yeasts, macromolecular protein compounds, natural dyes, are stored at the enterprises.

Expanded perlite wastes from the filtration processes of the initial wine material have the following composition, in% mass:

pearlite 7 ... 10 organic wine substances 25 ... 37 water 60 ... 65.

The sticky wastes are formed in the process of clearing and demetallizing the wine material. Initially, they contain bentonite and organic substances, namely yeasts, various sticky substances and components of wine, as well as Berlin blue. The flotoslam of the adhesive waste in the form of the foam is formed when alkalizing the ferrocyanides in the process of demetallizing them, realized by separating the liquid phase from the solid one by electroflotation.

MD 294 Z 2011.07.31

The process of selective alkalization of the heavy blue-soluble form of Berlin blue from the sticky sediments is carried out by the processing with lime or sodium hydroxide, so the ferrocyanide of its insoluble form passes into soluble form according to the reactions:

Fe '^1I[Fe^1I(CN) 6] 3 + 3NaOH ^ 3NaFe^1I1[Fe¹¹(CN) 6] + Fe (OH)₃ Ф or

2FeJⁿ[Feⁿ(CN) 6] 3 + 3Ca (OH) 2 -> 3Ca {Fe^us[Feⁿ(CN) 6]}₂ + 2 Fe (OH)₃ Ф

Electroflotation separation of the formed suspension is performed in devices with continuous action at the DC current intensity at 3 ... 7 V electrodes, the cathodic density of 1.0 ... 5.0 А / dm² with the specific current consumption for this operation of 0.1 ... 0.15 kW / m³. The separation speed by electroflotation of the phases is 2 ... 5 min.

The Berlin blue soluble solution is further removed for later use, and the foaming floating product, which confers bentonite particles with organic components, is enriched with electrolyzed hydrogen bubbles. Its initial composition includes,% mass:

bentonite 3 ... 7 organic components (yeast) 28 .. .35 water 58 ... 69.

The mixing of expanded perlite waste from the filtration processes of the wine material with the flotoslam electrolyzed by bentonite and yeast from the alkalization of the sticky sediments from the vinification to the homogeneous mass is carried out in standard agitators with a screw. In this operation, the process of neutralization when mixing waste with acid reaction and those with alkaline environment is important.

The atmosphere of regeneration of the processes of combustion of natural gas or of biogas takes place in the stove with continuous regime, for example, of the type ЭН-125 М2, in which о atmosphere with the following composition is formed, in% vol .:

CO - up to 24

H₂ - up to 30

СНд and CO₂ - up to 1

N₂ - the rest.

Following the non-oxidizing heating in the area of ​​optimum heating temperatures of the solution under isothermal conditions, the mixture is dried, its pyrolysis and the carbonization of the organic components on the mineral particles of pearlite and bentonite, consequently on their surface a activated carbon layer with increased sorbfunctional properties is formed.

Due to the use of electrolyzed slurry, saturated with hydrogen, in the process of explosive combustion of its bubbles, the formation of macro- and micropores on the carbon surface is improved. Following the regenerating atmosphere that is formed in the process of burning the endogas, a high degree of activation of the carbonized surface of the mineral-carbon adsorbent is ensured. This excludes the need to use a special surface activation, which is commonly used in adsorbent refining technology, which simplifies the process of refining the sorbents and facilitates the improvement of the properties of the obtained material, which can be used for wastewater treatment.

The presence of the mineral matrix provides the adsorbent with increased mechanical properties. The use of waste in the proposed process allows to reduce the expenses in its realization and to have a beneficial influence on the ecological status of the wineries.

Example

Mixing of expanded perlite wastes from the filtration processes of the wine material was carried out with the flotoslam electrolysed by bentonite and yeast from the alkalization of the sticky sediments from the wine production in the ratio, in mass%, 70:30. Preliminarily the obtained mixture was dried to the remaining 7% humidity. Thermal processing and carbonization was carried out in the burning atmosphere of the endogas at 450 ° C for 1 hour. The dynamic sorption capacity after sulfanol, the specific surface area and the summary volume of the pores were estimated.

MD 294 Z 2011.07.31

The comparative results are presented in the table.

Table

<td rowspan="2">Nr.</td><td colspan="4">terms</td><td colspan="4">Properties of adsorbents</td>

<td>Sediment processed by expanded perlite,% mass</td><td>Bentonite-yeast electrolyte float,% mass</td><td>Temperature, ° C</td><td>Processing time, hours</td><td>Dynamic sorption capacity,% mass</td><td>Specific area, m²/ g</td><td>Summary of the pore volume, cm²/ g</td><td>Resistance R / V,%</td>

<td colspan="9">According to the proposed conditions</td>

<td> 1</td><td> 70</td><td> 30</td><td> 450</td><td> 0,5</td><td> 1,8</td><td> 320</td><td> 0,65</td><td> 68</td>

<td> 2</td><td> 60</td><td> 40</td><td> 500</td><td> 1</td><td> 2,1</td><td> 370</td><td> 0,86</td><td> 65</td>

<td colspan="9">According to the nearest solution</td>

<td>3l</td><td> 1 100 1</td><td> -</td><td> 1 500</td><td> 1 3</td><td>J У 1</td><td> 1 280 1</td><td> 1 0,60 1</td><td> 1 58</td>

(56) Bibliographic references cited in the description:

1. MD588 G2 1997.03.31

2. MD 2356 G2 2004.08.31