EA026381B1 - Activated mineral powder for asphalt concrete mixes - Google Patents

Abstract

The invention relates to production of road-building materials and can be used in production of asphalt concrete and other organo-mineral mixes used in road-building construction. The task solved by the invention is reducing bitumen content and decreasing heavy metals ion migration into the environment. The assigned task is solved by that an activated mineral powder for asphalt concrete mixes comprising ground carbonate mineral material and slime of galvanic productions further comprises ground quartz sand and oil waste with the following component ratio, wt.%: slime of galvanic productions - 25-30, carbonate mineral material - 45-50, quartz sand - remaining, oil waste - 5.8-6.5 (over 100%).

Description

The invention relates to the production of road-building materials and can be used in the preparation of asphalt concrete and other types of organic-mineral mixtures used in road construction, etc.

Known mineral powder [1] in the form of waste ion-exchange plants containing heavy metal ions, which is used in the preparation of asphalt mixtures.

The disadvantage of mineral powder is the complex technology for the preparation of asphalt mixtures and the low strength of asphalt concrete.

Known mineral powder [2] in the form of carbonate mineral material modified 8-12% sludge galvanic production, used in the manufacture of asphalt mixtures. Sludge galvanic production contains metal hydroxides in terms of dry matter, wt.%: Calcium - 30-70; iron - 7-60; copper - 0.1-12; zinc - 0.1-18; chromium - 0.1-16; nickel - 0.013; aluminum - 0-8; cadmium - 0-0.5; other metals (cobalt, manganese, lead, tin) - 0-1.5, insoluble in inclusion acids - 0-28.

The disadvantage of the mineral powder is that it has a high bitumen intensity due to the large specific surface of the metal hydroxides contained in the sludge, in addition, when wetting asphalt concrete with this powder, heavy metal ions migrate from the sludge into the environment, since the crushed carbonate material does not enter into ion exchange with all heavy metal ions. Bitumen in asphalt concrete does not cover the entire surface of the powder and does not completely block the migration of ions.

The closest in technical essence and the achieved result is a mineral powder [3] in the form of galvanic waste (sludge) used in the preparation of asphalt mixtures. Waste galvanic production have the following composition in terms of dry matter, wt.%:

Cr (OH) ₃ 3.62-4.26

Νί (OH) ₂ 6.40-6.53

Cu (OH) ₂ 5.07-5.31 Ζη (OH) ₂ 2.61-2.75

Re (OH), 6.38-6.51

Sat (OH) ₂ 0.65 - 1.31

A1 (OH) s 2.12-2.46 810g 6.67 - 8.48

CaO 63.68 - 65.22

The disadvantage of the prototype is that it has a high bitumen intensity due to the large specific surface of metal hydroxides, in addition, when wetting asphalt concrete, migration of heavy metal ions into the environment is observed.

The problem solved by the invention is to reduce bitumen and decrease the migration of heavy metal ions into the environment.

The problem is solved in that the activated mineral powder for asphalt mixtures, including crushed carbonate mineral material and sludge from galvanic plants, additionally contains crushed silica sand and oil swelling in the following ratio of components, wt.%:

sludge from galvanic production 25-30 carbonate mineral material 45-50 quartz sand, the rest is up to 100% oily edema 5.8 - 6.5 (in excess of 100%).

Activated mineral powder is prepared by drying sludge from galvanic plants, carbonate mineral material and silica sand, followed by grinding in the presence of oily edema to the required grinding fineness. With joint grinding, the physicochemical parameters of the mineral surface change, which affects its ability to absorb heavy metal ions contained in the sludge of galvanic plants, such as chemically precipitated heavy metal hydroxides (A1 + ³ No. ^{+ 2} , Cr ⁺³ , Ζη ' ² , Cu' ^2. Sat ' ² , Fe ⁺³ ), which have a high specific surface. Heavy metal ions as a result of powerful physical and mechanical effects during grinding fall on the freshly formed surface of mineral materials. In this case, isomorphic substitution occurs. Heterovalent ion exchange is carried out according to the rule A.E. Fersman. Ions with a higher charge enter the crystal lattice more easily than ions of lower charges. Carbonate mineral material provides ion exchange with Ca ' ² ions, silica sand - with δί ⁺² ions. The activating substance is oil swelling, blocks heavy metal ions, creating a waterproof shell. Such activated mineral powder has a hydrophobic surface that interacts well with bitumen in the structure of asphalt concrete, which also contributes to the uniform distribution of thin layers of bitumen on mineral grains. Due to the shell of bitumen and an activating substance on the surface of the mineral powder, the migration of heavy metal ions into the aquatic environment is prevented when the asphalt concrete is wetted by atmospheric precipitation. Per

- 1 026381 due to the complex surface treatment of the grains of mineral powder, its bitumen intensity is reduced.

In laboratory conditions, the sludge of galvanic production was dried during its heat treatment with gases having a temperature of 250-300 ° C. After cooling the sludge of galvanic plants to a temperature of 50-70 ° C, it was crushed together with carbonate mineral material, sand and oil swelling to a fineness of grinding with particles finer than 0.071 mm over 60 wt.%. The compositions of the activated mineral powder and the mineral powder of the prototype, as well as the results of tests for bitumen in accordance with GOST 16557 are presented in table. one.

Table 1

No. p.p. compositions mineral powder Carbonate mineral material, May. % Sludge electroplating productions, May. % Quartz sand, May. % Edema oil, in may. % Bitumen CAPACITY, g 1 (prototype) - one hundred 80 2 47.5 22.5 thirty 6.2 51 3 47.5 25 27.5 6.2 51 4 47.5 27.5 25 6.2 51 5 47.5 thirty 22.5 6.2 57 6 47.5 32,5 20,0 6.2 68 7 42.5 27.5 30,0 6.2 66 8 45.0 27.5 27.5 6.2 55 nine 50,0 27.5 22.5 6.2 58 10 52,5 27.5 20,0 6.2 65 eleven 47.5 27.5 25.0 5,6 70 12 47.5 27.5 25.0 5.8 60 thirteen 47.5 27.5 25.0 6.5 69

As evidenced by the data, in comparison with the prototype significantly reduced bitumen intensity of the claimed activated mineral powder.

To study the migration of heavy metal ions, two compositions of an asphalt concrete mixture of the optimal composition ЩМБ П / 2,3 according to STB 1033-2004 were prepared, the first using the inventive activated mineral powder of composition No. 3, and the second with a prototype mineral powder. The bitumen content in the asphalt mix on the activated mineral powder was 5.6%, and on the prototype mineral powder - 6.0%. Samples of cylindrical asphalt concrete were kept in clean water and water with a pH of 4.11 (aggressive environment).

Analysis of samples of water extracts of asphalt concrete for the content of heavy metal ions in them was carried out on a TA-4 voltammetric analyzer using a mercury film indicator electrode and a silver silver comparison electrode.

In the table. 2 shows the content of heavy metals in water extracts of asphalt concrete.

table 2

Solutions in which water saturated samples Asphalt Sample The content of heavy metals, mg / l Ζη Pb Si Pure water Prototype 1.25 0.05 1.32 Activated mineral powder 0.24 0.017 0.82 The solution of aggressive environment (14 days) Prototype 1.32 0,043 1,2 Activated mineral powder 0.32 0.018 0.5 A solution of aggressive environment (28 days) Prototype 1.42 0.35 1.14 Activated mineral powder 0.43 0.012 0.56

As a result of the tests, it was found that the use of activated mineral powder in asphalt concrete compared to the prototype reduces the migration of copper ions by an average of 4 times, zinc and lead by 2 times.

Samples of asphalt on the claimed activated mineral powder and mineral powder prototype of the above compositions were tested for compliance with the requirements of STB 1033-2004.

The physicomechanical properties of asphalt concrete from a mixture of ЩМБ П / 2,3 on activated mineral powder and mineral prototype powder are presented in table. 3.

Table 3

Indicators Requirements STB 1033-2004 Unactivated mirap powder (prototype) Activi- bathroom mine real powder Output ABOUT according in required Niyam TYPE one 2 3.0 4 The average density, g / cm ³ - 2.43 2.45 - Water saturation,% by volume 1.00-4.00 7.1 2.0 Acc. Swelling,% by volume No more than 1.00 0.63 0 Acc. The compressive strength at 50 ° C, MPa Not less than 1,0 1.11 1.72 Acc. Water resistance coefficient during prolonged water saturation in clean water after 28 days - 0.67 0.82 - Water resistance coefficient during prolonged water saturation in a solution of an aggressive environment Not less than 0.7 0.55 0.76 Acc.

From the data presented it follows that asphalt concrete using activated mineral powder meets regulatory requirements and has the best indicators for water resistance. This ensures the environmentally friendly disposal of waste from galvanic production (sludge) by reducing the migration of heavy metal ions into the environment. The need for bitumen is reduced in the preparation of asphalt concrete by reducing the bitumen intensity of activated mineral powder.

Sources of information taken into account when filling out the application.

1. USSR author's certificate No. 614123, MKI C08 95/00, 1976.

2. Patent KI 2012547, С04В 26/26, С08Ь 95/00, 1994.

3. USSR Author's Certificate No. 968046, MKI SB04 13/30, publ. 10.23.82, bull. Number 39.

Claims (1)

CLAIM Activated mineral powder for asphalt mixes, including crushed carbonate mineral material and electroplating sludge, characterized in that it further contains crushed quartz sand and oil swelling in the following ratio, wt.%: Electroplating sludge - 25-30, carbonate mineral material - 45-50, quartz sand - the rest is up to 100%, oil edema - 5.8-6.5 (in excess of 100%).