RU2478592C1 - Method of producing sulphur-asphalt compositions having low emission of hydrogen sulphide and sulphur dioxide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to production of compositions containing asphalt and sulphur which can be used in road and other construction. The method of producing sulphur-asphalt compositions involves merging, while stirring, an asphalt-concrete mixture heated to temperature of 140-150°C and sulphur granules having geometrical dimensions not greater than 10 mm, obtained by granulation of a mixture containing 86.21-90.50 wt % of powdered sulphur having particle size not greater than 0.5 mm, 9.05-12.93 wt % of an organic component having melting point higher than 70°C (substances containing fatty acids or saturated C₁₈H₃₈…C₅₅H₁₁₂ hydrocarbons) and 0.45-0.86 wt % of an emission neutraliser (metal oxides or mixtures thereof which form water-insoluble or partially soluble sulphides and/or sulphites with said gases).

EFFECT: improved technology of producing sulphur-asphalt compositions, reducing emission of hydrogen sulphide and sulphur dioxide when producing, transporting and applying a sulphur-asphalt-concrete mixture.

1 ex, 1 tbl

Description

The production method relates to the production of compositions containing bitumen and sulfur, which can be used in road and other construction.

A known method of producing asphalt concrete with sulfur [1], which consists in introducing sulfur (liquid or lump) into a bitumen boiler, equipped with a propeller or screw type mixer, filled with bitumen not more than 0.75 of its volume, mixing the mixture at a temperature of 130-140 ° C for 10 min for liquid sulfur or 20 min for lump sulfur. Next, the preparation of the asphalt mixture is carried out in the usual manner.

The disadvantage of this method are:

1) low temperature of the asphalt concrete mixture containing sulfur additive - 130-140 ° С - which reduces the quality of the asphalt concrete coating;

2) emission of hydrogen sulfide and sulfur dioxide in the manufacture of mixtures, their transportation and installation.

A known method of producing sulfur-bitumen binder (patent No. 2284304), intended for the preparation of road-building materials and consisting in mixing components - molten bitumen and sulfur when heated at a temperature of 140-180 ° C, with 1-5 wt.% Pre-added to the molten bitumen styrene-dicyclopentadiene-indene resin or alkadiene-dicyclopentadiene-indene resin and 1-5 wt.% high molecular weight hydrocarbons - alpha-olefins of fractional composition C _twenty -FROM ₂₆  with a melting point of 38-40 ° C and / or industrial oil with a viscosity of 5-50 mm ² / s at 50 ° C and stirred for 0.5 hours, then sulfur is added in portions in a mass ratio with bitumen 10-50: 90-50, respectively, and stirred for another 2 hours.

The disadvantage of this method are:

1) high energy costs (temperature 140-180 ° C) and the complexity of the technology for producing sulfur-bitumen binder (2-2.5 hours);

2) emission of hydrogen sulfide and sulfur dioxide in the manufacture of sulfur-bitumen binder.

Also known is the composition of the binder for preparing the asphalt-bitumen mixture (patent No. 2378209), which allows using it to increase the softening temperature of concrete, lower the temperature of brittleness and eliminate environmental and corrosion problems. This is achieved by using sulfur in the binder and the use of ferric hydroxide, which is an adsorbent of sulfur dioxide, which reduces the release of the latter during the preparation and paving of asphalt and at the same time reduces the corrosiveness to technological equipment, increases the strength characteristics and improves the environmental situation. The binder for the preparation of asphalt mixture contains, wt.%:

Bitumen - 41-43 Sulfur - 54-56 Mineral oil - 2.1-2.35 Lime - 0.1-0.6 Ferric hydroxide - 0.2-0.5 CMC - 0.02-0.03 Polymer - 0.02-0.08

The disadvantages of this composition are the low adsorption of sulfur dioxide by ferric hydroxide and the formation of water when interacting with sulfur dioxide gases, which is unacceptable for the technology of sulfur-bitumen materials.

Closest to the invention is a method of reducing emissions of hydrogen sulfide from cast sulfur-asphalt mixtures (US patent No. 3960585 "Reducing H ₂ S-emission from hot cast sulfur-asphalt mixtures "), which consists in introducing into bitumen, heated to a temperature of not more than 150 ° C, an organic component (tetraalkylthiuram disulfide, zinc dialkyl dithiocarbamate, diphenyl guanidine) and a redox catalyst (iodine, oxide and copper salts , iron oxide and salts, cobalt oxide and salts), followed by the addition of sulfur. These organic components and redox catalysts are introduced into the mixture in amounts not exceeding 0.5% by weight of the mixture of bitumen with sulfur. The most effective reducers (neutralizers) of hydrogen sulfide emission are iron chlorides: FeCl ₂ 4H ₂ O and FeCl ₃ 6H ₂ O.

The disadvantages of this method are:

1) the method allows to reduce the emission of only hydrogen sulfide, however, the practice of preparing and laying sulfur-asphalt concrete shows that, together with the emission of hydrogen sulfide, sulfur dioxide emission occurs;

2) the use of organic components potentially hazardous to human health;

2) the use of water-soluble iron chlorides, causing equipment corrosion and reducing the quality of asphalt concrete pavements.

The technical task of the invention is the improvement of the technology for producing sulfur-bitumen compositions by changing the method of introducing sulfur and the composition of the catalyst for the emission of hydrogen sulfide and sulfur dioxide, which reduces the emission of hydrogen sulfide and sulfur dioxide in the process of manufacturing, transportation and paving of asphalt concrete.

The problem is solved by combining the asphalt mixture heated to a temperature of 140-150 ° C with prefabricated sulfur granules with geometric dimensions of not more than 10 mm, containing 9.05-12.93 wt.% Organic component with a melting point of not more than 70 ° C and 0.45-0.86 wt.% The emission neutralizer.

As the organic component, substances containing fatty acids or saturated hydrocarbons of composition C are used. _eighteen H ₃₈ …FROM ₅₅ N ₁₁₂ for example: gossypol resin, paraffin, ceresin, stearic acid and others, as well as dehydrated industrial waste containing these compounds, or a mixture thereof.

As a catalyst for the emission of hydrogen sulfide and sulfur dioxide, metal oxides or mixtures thereof are used, which form water-insoluble or poorly soluble sulfides and / or sulfites with these gases. These metal oxides include: manganese oxide, lead (II) oxide, bismuth (III) oxide, tin oxide, iron (II) oxide, iron (III) oxide, zinc oxide, copper oxide.

Granules of sulfur are prepared as follows. A metered amount of metal oxides is introduced into the organic component (optionally heated to its melting point). The mixture is thoroughly mixed until a homogeneous mass. Then a metered amount of sulfur is introduced with a particle size of not more than 0.5 mm. The resulting mixture is stirred at a temperature of not more than 80 ° C until a homogeneous mass. Then the mixture is cooled and, if necessary, crushed to particles (sulfur granules) with a size of not more than 10 mm.

The obtained sulfur granules are introduced into the asphalt mixture with a temperature of 140-150 ° C. The presence of sulfur and an organic component provides a modification of bitumen, which leads to an increase in the performance of asphalt concrete pavement. The use of emission neutralizers provides a reduction in the emission of hydrogen sulfide and sulfur dioxide in the process of manufacturing, transportation and laying of asphalt mix.

Thus, the totality of the claimed essential features of the invention ensures the achievement of the specified technical result.

An example of a specific implementation.

14 kg of gossypol resin (TU 9147-141-00336562-2008) and 0.70 kg of zinc oxide (GOST 10262-73) are added to a mixer with an oil jacket with a capacity of 20 l, equipped with a paddle mixer, and mixed for 15-20 minutes until a homogeneous masses. Then 5.7 kg of the obtained mixture of gossypol resin and zinc oxide are loaded into a batch mixer-granulator equipped with a heating system, 54 kg of powdered sulfur (GOST 127-93) with a particle size of not more than 0.5 mm are added, the mixture is heated to a temperature of 60 -70 ° C, mix and form granules for 3-5 minutes Sulfur granules in an amount corresponding to a decrease in bitumen consumption (10-40%) are added to the asphalt mixture heated to 140-150 ° C, mixed for 30-60 s. Sulfur-asphalt concrete mixture is transported and laid at the facility.

The results of experimental studies of the claimed method for producing sulfur-bitumen compositions are presented in table 1.

As can be seen from the test results, the emission of hydrogen sulfide and sulfur dioxide from sulfur-bitumen compositions heated to a temperature of 140-150 ° C is significantly lower.

Table 1 Composition number Content, wt.% Multiplicity of emission reduction Bitumen Sulfur Organic component Catalytic converter H ₂ S SO ₂ one 70.00 30.00 - - 1,0 1,0 2 65,99 28.23 5.64 (paraffin) 0.14 (lead oxide) 1,2 1.4 3 67.90 29.05 2.90 (gossypol resin) 0.15 (zinc oxide) 12.6 49.3 four 67.90 29.05 2.90 (gossypol resin) 0.15 (iron oxide) 3.2 3.9 5 67.90 29.05 2.90 (gossypol resin) 0.15 (zinc oxide, copper oxide) 12.8 49.6 6 67.90 29.05 2.90 (gossypol resin + paraffin) 0.15 (zinc oxide, copper oxide) 11.8 48.6 7 67.90 29.05 2.90 (gossypol resin + stearic acid) 0.15 (zinc oxide, copper oxide) 13.6 45.6

Literature

1. The allowance for the construction of asphalt concrete pavements and the bases of roads and airfields (to SNiP 3.06.03-85 and SNiP 3.06.06-88) - M., 1990.

2. Patent No. 2284304, MKI SB04/26 "Method for producing sulfur-bitumen binder."

3. Patent No. 2378209, MKI С04В 26/26 “The composition of the binder for the preparation of asphalt-bitumen mixture”

4. US patent No. 3960585, MKI C08L 95/00 "Reducing H ₂ S-emission from hot cast sulfur-asphalt mixtures. "

Claims (1)

A method of producing sulfur-bitumen compositions with a reduced emission of hydrogen sulfide and sulfur dioxide by combining an asphalt concrete mixture with sulfur, characterized in that, in order to reduce the emission of hydrogen sulfide and sulfur dioxide, sulfur granules are introduced into the asphalt mixture heated to a temperature of 140-150 ° C. sizes not exceeding 10 mm obtained by granulating a mixture containing 86.21-90.50 wt.% powdered sulfur with particle sizes not exceeding 0.5 mm, 9.05-12.93 wt.% organic component with a melting point not more than 70 ° C (substances containing fatty acids or saturated hydrocarbons of the composition C ₁₈ H ₃₈ ... C ₅₅ H ₁₁₂ ) and 0.45-0.86 wt.% an emission neutralizer (metal oxides or their mixtures forming water-insoluble or poorly soluble sulfides with these gases and / or sulfites), stirred for 30-60 s.