RU2814674C1 - Method of producing binder based on industrial wastes - Google Patents

Abstract

FIELD: chemistry; various technological processes.

SUBSTANCE: invention relates to a method of producing a binder based on industrial wastes, which can be used in the cement and construction industries. Method of producing a binder based on industrial wastes comprises grinding portland cement clinker and industrial wastes. Wastes of vanadium production are used as industrial wastes, containing, wt.%: SiO₂ 3.22; Al₂O₃ 0.41; CaO 36.93; MgO 5.03; V₂O₅ 2.81; Mn₂O₃ 17.39; SO₃ 33.02; losses during calcination 1.19, and ash-slag wastes ASW-1, containing, wt.%: Na₂O 0.78; MgO 2.63; Al₂O₃ 22.15; SiO₂ 52.39; K₂O 1.94; CaO 3.59; TiO₂ 1.05; MnO 0.69; Fe₂O₃ 7.73; P₂O₅ 0.36; SO₃ 0.37; loss on ignition 6.32. Said vanadium production wastes are mixed with ash-and-slag wastes at a weight ratio of 2:1, 84–86 wt.% of portland cement clinker is added and the mixture is ground together in a centrifugal-planetary mill for 0.25 h to specific surface area of 6,400 cm²/g.

EFFECT: reduced power consumption, higher quality of end product.

1 cl, 5 tbl, 1 ex

Description

The invention relates to a method for producing a binding material based on technogenic waste, which can be used in the cement and construction industries.

There are known methods for producing a binder material, including a method for producing a binder based on Portland cement and dust from electrostatic precipitators of ferroalloy production, the disadvantages of which are the relatively low quality of the final product and the high energy intensity of their production ["Binder", RF patent No. 1031934 C04B7/35, publ. 07/30/1983].

The closest in technical essence adopted as a prototype is the method for producing a binder material - described in ["Cement", RF patent No. 2119897 C04B 7/04 (2006.01), C04B 28/04, publ. 10.10.1998] including a method for producing a binder by using waste from the production of aluminum fluoride - acid fluoride, which is obtained by reacting fluorspar (fluorite) concentrate with 98.5% sulfuric acid. To neutralize residual sulfuric acid, the resulting product was treated with a calcium-containing substance, which was used as technological dust from electric precipitators installed in the Portland cement clinker gas purification system. The acid fluoride was crushed to a particle size of 20 mm, mixed with pre-ground and dried gypsum stone and fed into a cement mill for co-grinding with Portland cement clinker.

The disadvantages of this method of producing binder material are the high energy intensity of its production and the low quality of the final product.

The technical result of the proposed invention is to reduce the energy intensity of producing a binder based on technogenic waste, reduce the grinding time of the binder and improve the quality of the final product.

This is achieved by the fact that the method of producing a binder based on man-made waste includes grinding Portland cement clinker and man-made waste, while vanadium production waste containing, wt.%: SiO ₂ 3.22; Al ₂ O ₃ 0.41; CaO 36.93; MgO 5.03; V ₂ O ₅ 2.81; Mn ₂ O ₃ 17.39; SO ₃ 33.02; loss on ignition 1.19, and ash and slag waste ZShO-1 containing, wt.%: Na ₂ O 0.78; MgO 2.63; Al ₂ O ₃ 22.15; SiO ₂ 52.39; _K2O 1.94; CaO 3.59; TiO ₂ 1.05; MnO 0.69; Fe ₂ O ₃ 7.73; P ₂ O ₅ 0.36; SO ₃ 0.37; loss on ignition 6.32, mix the specified vanadium production waste and ash and slag waste at a weight ratio of 2:1, add 84-86 wt.% Portland cement clinker and co-grind the mixture in a centrifugal-planetary mill for 0.25 hours to specific surface 6400 cm ² /g.

A raw material mixture was prepared consisting of vanadium production waste and ash and slag waste in a weight ratio of 2:1. Then Portland cement clinker was added and crushed to a specific surface area of 6400 cm ² /g.

The operating parameters of the Sand centrifugal planetary mill were as follows: drum rotation speed 325s ^-1 ; The material of the mill and balls is chalcedony. Portland cement 84.0 wt.%, vanadium production waste and ash and slag waste ZShO-1 were loaded into a centrifugal planetary mill at a ratio of 2:1 parts by weight in an amount of 16.0 wt.% and the mixture was ground to a specific surface area of 6400 cm ² /g . The particle sizes of vanadium production waste, ZShO-1 and Portland cement clinker were 3.5-3.6 microns. The optimal grinding time was 0.25 hours.

During the joint grinding process, mechanical activation of vanadium production waste particles and ash and slag waste particles with Portland cement clinker particles occurs, which 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. Mechanically activated particles of ash and slag waste contain a significant amount of glass phase, which plays a positive role in the nucleation of crystallization centers during cement mixing and provides high strength properties of the final product. The use of a centrifugal planetary mill allows reducing energy costs by 3 times and reducing grinding time by more than 10 times. The combined use of vanadium production waste and ash and slag waste in an amount of 14-16 wt.% leads to a significant increase in strength.

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 6400 cm ² /g binder components

Mill name Grinding time, h Ball porcelain mill with urolite balls 4.0 Centrifugal planetary mill 0.25

The mixture was extracted and samples were molded into cubes 30x30x30 mm with a water-cement ratio (W/C) of 0.24. After hardening in air for 24 hours, the cubes were removed from the mold and subjected to heat and humidity treatment in a LOIP steaming chamber for 6 hours at a temperature of 85°C, and then the samples were hardened in air for 28 days.

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 vanadium production waste, ZShO-1 and Portland cement influenced the strength characteristics of the final product and specific surface area (Table 2).

table 2

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* 6400* 3.5-3.6* 4. 20 6550 3.4-3-5 * - optimal parameters

As can be seen from Table 2, the optimal grinding time was 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 parameters, decreased to 6200 mm ² /g, and the average particle size was in the range of 5.0-7.0 microns, which significantly reduced the grade of the binder material (less than the grade of binder material M 400).

The dispersity of crushed particles of the original Portland cement clinker, vanadium production waste and ZShO-1 after grinding was determined using an ANALYSETTE 22 NanoTecplus laser particle size analyzer. The compressive strength of the cubes was carried out on a PMG-100 MG4 hydraulic press. Compressive strength was determined as the average strength of five samples, which was 57.3 MPa.

The optimal ratios of the components of binder materials, obtained experimentally, are presented in Table 3.

Table 3

Portland cement clinker, wt. % Content of the mixture of vanadium production waste and ash and slag waste, wt. % The ratio of vanadium production waste and ash and slag waste, weight parts Compressive strength, MPa 88.0
86.0
84.0
82.0 12.0
14.0
16.0
18.0 2:1 50.8
55.9
57.3
52.4

Characteristics of the components used:

1. Portland cement clinker produced by Srebryakovcement OJSC, grade CEM II/A 42.5N (GOST 31108-2016) with a specific surface of 3200 cm ² /g of the following chemical composition (Table 4).

Table 4

Chemical composition of Portland cement, wt. %

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 1.05

2. Vanadium production waste, the chemical composition of the waste is presented in Table 5 [Possibility of using vanadium production waste in the technology of wall ceramics / Bessmertny V.S. etc. // Glass and ceramics. 2022. T. 95, No. 7. P. 43-50].

Table 5

Chemical composition of vanadium production waste

Mass. % _{SiO2 Al2O3 ​} CaO MgO _{V2O5 Mn2O3 ​} SO ₃ p.p.p. 3.22 0.41 36.93 5.03 2.81 17.39 33.02 1.19

3. Ash and slag waste ZShO-1, the following chemical composition (wt.%): Na ₂ O - 0.78; MgO - 2.63; Al ₂ O ₃ - 22.15; SiO ₂ - 52.39; K ₂ O - 1.94; CaO - 3.59; TiO ₂ - 1.05; MnO- 0.69; Fe ₂ O ₃ - 7.73; P ₂ O ₅ - 0.36; SO ₃ - 0.37; p.p.p - 6.32 [Possibility of using solid fuel combustion waste from thermal power plants in the Arctic zone of the Russian Federation in eco-geopolymer technology / E.A. Yatsenko and others // Glass and ceramics. 2021. No. 9.S. 40-45].

Example:

A raw material mixture was prepared, consisting of Portland cement clinker in an amount of 8.6 kg, a mixture of vanadium production waste and ZShO-1 ash and slag waste at a ratio of 2:1 parts by weight, respectively, in an amount of 1.4 kg. The resulting mixture was placed in a centrifugal planetary mill and co-grinding was carried out to a specific surface area of 6400 cm ² /g. Samples were molded and tested for strength.

The average compressive strength of the cubes was 57.9 MPa, which corresponds to the grade of binder material M 500.

Claims (1)

A method for producing a binder based on man-made waste, including grinding Portland cement clinker and man-made waste, characterized in that vanadium production waste containing, wt.%: SiO ₂ 3.22; Al ₂ O ₃ 0.41; CaO 36.93; MgO 5.03; V ₂ O ₅ 2.81; Mn ₂ O ₃ 17.39; SO ₃ 33.02; loss on ignition 1.19, and ash and slag waste ZShO-1 containing, wt.%: Na ₂ O 0.78; MgO 2.63; Al ₂ O ₃ 22.15; SiO ₂ 52.39; _K2O 1.94; CaO 3.59; TiO ₂ 1.05; MnO 0.69; Fe ₂ O ₃ 7.73; P ₂ O ₅ 0.36; SO ₃ 0.37; loss on ignition 6.32, mix the specified vanadium production waste and ash and slag waste at a weight ratio of 2:1, add 84-86 wt.% Portland cement clinker and co-grind the mixture in a centrifugal-planetary mill for 0.25 hours to specific surface 6400 cm ² /g.