RU2810086C1 - Method for producing binder - Google Patents

Abstract

FIELD: construction materials.

SUBSTANCE: invention relates to production of binders based on glass household waste used in production of building materials and in construction. The method involves averaging by grinding Portland cement with industrial waste. In this case, glass scrap of sheet and container glass is used as industrial waste, which is pre-crushed and then ground in a centrifugal planetary mill to a specific surface area of 6,500 cm²/g. Subsequent co-grinding of a mixture of Portland cement and 30-50 wt.% of glass powder is carried out to a specific surface area of 6,500 cm²/g, obtaining particles with a size of 3.5-3.6 mcm.

EFFECT: reduction in material consumption due to partial replacement of cement and energy consumption.

1 cl, 4 tbl, 2 ex

Description

The invention relates to methods for producing binders and can find application in the production of building materials and in construction.

There are a number of known methods for producing binders, including averaging the main component with various industrial wastes [Patent RU2148041 Dry cement mixture. Publ. 04/27/2000;], the disadvantage of which is relatively low quality and high energy intensity.

The closest to the proposed method is the method of producing a binder, which includes averaging Portland cement and dust from electrostatic precipitators for the production of ferrosilicochrome [Patent SU 1031934 A, Binder. Published July 30, 1983].

The disadvantages of the analogue are high energy consumption and material consumption.

The purpose of the invention is to reduce material consumption and energy consumption. This goal is achieved by the fact that the method of obtaining the binder includes averaging by grinding Portland cement with industrial waste, and is distinguished by the fact that glass scrap of sheet and container glass is used as industrial waste, which is pre-crushed and then ground in a centrifugal planetary mill to a specific surface of 6500 cm ² /g, subsequent joint grinding of a mixture of Portland cement and 30-50 wt.% glass powder is carried out to a specific surface of 6500 cm ² /g, obtaining particles with a size of 3.5-3.6 microns.

In the process of joint grinding, where the components are ground down, mechanical activation of glass particles with Portland cement particles leads to the occurrence of solid-phase reactions due to an increase in the surface and internal energy of all particles and a shift of the limiting stage from the diffusion region to the kinetic one.

To speed up the technological process, reduce energy costs by 2-3 times and reduce grinding time by more than 10 times for the purpose of mechanical activation of particles, it is necessary to use a range of grinding equipment - centrifugal planetary mills.

The experimentally obtained parameters of grinding and mechanical activation of the mixture are presented in Table 1.

Table 1

Grinding time to specific surface area of 6500 mm ² /g binder components

No.
p/p Mill name Grinding time, hour 1. Ball porcelain mill with urolite balls 4.0 2. Centrifugal planetary mill 0.25

Example 1

The starting material was Portland cement produced by Srebryakovcement OJSC, grade CEM II/A 42.5N according to GOST 31108-2016, with the following chemical composition (Table 2).

table 2

Chemical composition of Portland cement

CaO _{SiO2 Al2O3 _ Fe2O3 _} MgO SO _{3 R2O} p.p.p. 62.44 21.29 5.72 3.37 2.09 2.83 1.21 1.10

The chemical composition of sheet and container glass is presented in Table 3.

Table 3

Chemical composition of sheet and container glass

Name of glass Mass content, % _{SiO2 Al2O3 _} CaO MgO _{Na2O Fe2O3 _} SO ₃ Sheet glass 72.0 1.9 6.7 4.2 14.8 0.22 0.3 Green container glass 69.7 3.21 6.01 3.59 14.59 0.46 0.37

The cullet of sheet and container glass was pre-crushed at a ratio of 1:1 in a jaw crusher. Ultra-fine crushed glass was ground in a SAND centrifugal planetary mill for 15 minutes. The operating parameters of the centrifugal planetary mill were as follows: drum rotation speed 325s ^-1 ; The material of the mill and balls is chalcedony.

After grinding the mixture of sheet and container glass, Portland cement and glass powder were loaded into a centrifugal planetary mill at a ratio of 7:3 parts by weight and the mixture was ground to 6500 mm ² /g. The particle sizes of glass and Portland cement were 3.4-3.6 microns.

The finishing time was 15 minutes. The mixture was extracted and samples were molded into cubes 30x30x30 mm with a water-cement ratio (W/C) of 0.23. After hardening in air for 24 hours, the cubes were removed from the mold and subjected to heat and humidity treatment in a LOIP steam chamber for 6 hours at a temperature of 83ºC.

The superplasticizer “Melflux 1641” was used as a plasticizing additive, which was added to the mixture in excess of 100% - 0.16%.

The particle size of glass powder and Portland cement influenced the strength characteristics of the final product and specific surface area (Table 4).

Table 4

Effect of grinding time on specific surface area and particle size

No. Grinding time, min Specific surface area, cm ² /g Particle size, microns 1. 7 5800 More than 10 2. 10 6200 5.0-7.0 3. 15 6500 3.5-3.6 4. 20 6550 3.4

As can be seen from the table, the optimal grinding time was 0.25 hours or 15 minutes. When the grinding time increased to 20 minutes, the specific surface area increased slightly, and the energy consumption for grinding increased by 25%. With a grinding time of 10 minutes, the specific surface area, compared to the optimal option, decreased to 6200 mm ² /g, and the average particle size was in the range of 5.0-7.0 microns. This significantly reduced the quality of the binder - less than M400 grade.

The dispersity of crushed particles of the original Portland cement, glass powder and the mixture after grinding was determined using an ANALYSETTE 22 NanoTecplus laser particle size analyzer. The compressive strength of the cubes was carried out on a hydraulic press PMG-100 MG4. The average strength of the five samples was 51.9 MPa, which corresponded to the M 500 cement grade.

Example 2

A mixture of Portland cement and broken glass was prepared according to example 1 at a ratio of Portland cement and glass powder of 1:1 parts by weight, respectively.

Samples were formed and tested for strength according to example 1.

The compressive strength of the cubes was 46.5 MPa, which corresponds to the M 400 cement grade.

When the cullet in the mixture increases by more than 60 wt.%, the grade of the binder is below grade M 400.

Thus, the optimal content of finely ground glass in the binder lies in the range of 30-50 wt.%.

Claims (1)

A method for producing a binder, including averaging by grinding Portland cement with industrial waste, characterized in that cullet of sheet and container glass is used as industrial waste, which is pre-crushed and then ground in a centrifugal planetary mill to a specific surface area of 6500 cm ² /g, subsequent joint grinding of a mixture of Portland cement and 30-50 wt.% glass powder is carried out to a specific surface of 6500 cm ² /g, obtaining particles with a size of 3.5-3.6 microns.