RU1772096C - Extrusion asbestos cement mixture - Google Patents

Abstract

Use: for the production of extrusion asbestos-cement products. SUMMARY OF THE INVENTION: An extrusion asbestos-cement mixture contains May. %: asbestos 12-14; Portland cement 62-67; polyethylene oxide 0.6-0.7; nitrilotrimethylphosphonic acid 0.02-0.2 and water 19-24. Characteristics of the asbestos-cement mixture: potlife 5-8 hours; physical and mechanical characteristics of products aged 1, 7, and 28 days, respectively: bulk mass, g / cm3: 1.60-1.78; 1.64-1.81; 1.64-1.84; bending strength, MPa: 12.9-15.7; 21.4-22.3; 22.1-26.4; impact viscosity, kJ / m2: 2.7-2.9; 2.7-3.0; 2.7-3.0; water absorption,%: 20.0-24.5; 18.0-21.9; 17.9-20.9; frost resistance at the age of 28 days - 50 cycles. 1 tab. next to

Description

The invention relates to the building materials industry, in particular to the production of extrusion asbestos-cement products.

A known composition that increases the setting time of concrete or mortar mixtures based on cement of the following composition, May.%:

Sodium Chloride 9-25

Sodium Sulphate 25-45

Plasticizer 10-55

Thiosul sodium phosphate 10-25

Amino compound 0.1-2.0

Tests conducted in the laboratory of VNIIproektasbestsementa showed the impossibility of extrusion in general

asbestos-cement mixture in the presence of the additive proposed in the copyright certificate No. 908765.

The closest in technical essence to the claimed invention is the following composition of the raw material mixture, wt.%:

Asbestos16

Cement84

Polyethylene oxide 1.2 over 100%

Water30 over 100%

A disadvantage of the known composition is the loss of ability to extrude after storage for several hours (low pot life of the raw mix). Under production conditions

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N3 O

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forced stops of the production line with a duration of more than 1 hour. In these cases, the forming device is dismantled and the raw material mixture that has lost its molding properties is removed and weighs at least 3 tons (waste) that goes to the dumps.

After cleaning and assembling the equipment, before starting production, a raw mix of about 3 tons is passed through it, which is not used in the subsequent technological process and also goes to dumps.

The aim of the invention is to reduce waste, improve environmental conditions, increase productivity and reduce the complexity of production by increasing the pot life of the mixture.

This goal is achieved in that the extrusion asbestos-cement mixture, including asbestos, cement, polyethylene oxide as a hydraulic modifier and water, contains a complex hydraulic modifier-polyethylene oxide and nitrilotrimethylphosphonic acid (NTFC) in the following ratio of components (wt.%): Asbestos 12-14

Cement62-67

Polyethylene Oxide 0.6-0.7

NTFC0.02-0.2

Water19-24

The found complex hydraulic modifier - polyethylene oxide and NTFC - provides the extrusion of the asbestos-cement mixture with high viability, and, as a result, reduction of waste going to dumps, improvement of the environmental situation, increase in productivity and decrease in labor intensity of production. An example of a specific implementation. An experimental verification of an extrusion asbestos-cement mixture, including asbestos, cement, polyethylene oxide as a hydraulic modifier, and water, characterized in that that, in order to reduce waste going to dumps, improve the environmental situation, increase productivity and reduce the complexity of production by increasing its viability, the mixture contains a complex hydromodifier - polyethylene oxide (PEO) and nitriler imethylphosphonic acid (NTFC) in the following ratio of components (wt.%).

Asbestos 12-14

Cement62-67

PEO 0.6-0.7

NTFC0.02-0.2

Water19-24

was carried out in the laboratory of plasticizers and research methods of the Asbestos cement NGO.

Portland cement M-400 of the Belgorod cement plant (GOST) was used as raw materials

10178-76), chrysotile asbestos of the Bazhenovsky deposit of the P-5-50 group (GOST

12871-68), PEO Badimol brand production NRB (Sectors normal 0271481-85),

NTFC Novocheboksarsk Plant PO Himprom (TU 6-09-5283-86).

Raw mixtures were obtained by mixing dry asbestos and cement in a laboratory mixer 5, followed by the addition of a solution of PEO and NTFC.

The mass of the dry asbestos-cement mixture was 4000 g. The mixing time of the dry components was 5 minutes, with 0 solution - 10 minutes.

Samples were formed on the laboratory extrusion press from the prepared mixtures — beams 13030/10 mm in size, which after 1.7 and 28 days of hardening in an air-humid environment were subjected to physical and mechanical tests.

The pot life of the mixture was determined as the period from the time it was prepared to the loss of ability to extrude the mixture. The table shows the pot life of the mixtures and the physicomechanical parameters of the prepared samples: flexural strength (Ui), impact strength (Ore), water absorption (W) and bulk density (y). Frost resistance was determined only on samples of 28-day hardening - all samples withstood 50 cycles of alternate freezing and thawing without Q-delamination and other damage and reduction in strength. The strength of the current consumed by the engine of the extrusion press during extrusion during the first hour after the preparation of the raw mix was determined as an indicator of the plasticity of the raw material mixture.

As can be seen from the results presented in the table, a significant increase in the pot life of the mixture is observed by Q s when the content of NTFC in the mixture is from 0.02 to 0.2 wt%, while the physical and mechanical properties of samples aged 7 or more days significantly exceed the requirements of TU 21 -24-108-86; TU 21-24-89-81; TU 21-24-90-86 for various types of asbestos-cement extrusion products: according to RH 16.0-18.0 MPa: according to Yaud 2.0 kJ / m2; by 1.55-1.60 g / cm3 With an increased (in excess of 0.2 wt.%) content of NTFC, a sharp slowdown is observed5

the increase in the strength of the samples at an early (up to 1 day) age, which under production conditions due to the lack of breakdown strength, estimated for different types of products at 7-10 MPa, will lead to the destruction of products when they are removed from pallets during disassembling after passing through the preliminary hardening chamber.

As can be seen from the table, in the proposed extrusion mixture, the life span is increased by 2.5-5 times.

Beyond the limit of the maximum boundary value of the complex hydraulic modifier, there is a sharp drop in the strength of extrusion samples at the age of 1 day (Example No. 7), which leads to the destruction of the panels when they are removed from the pallet.

According to the laboratory of plasticizer-pde and research methods, with one disassembly and cleaning of the syringe machine, 3 tons of the raw material mixture go to dumps and the same amount is pushed during the start-up of the syringe machine (total b tons). The syringe machine stops 150- year. 190 times. Hence, the mass of waste is 150 x 6 900 tons, and at 190 x 6 1100 tons, i.e. the proposed complex hydromodifier allows

to save 900-1100 tons of expensive raw materials under production conditions and thereby significantly reduce asbestos cement dumps. The exclusion of the above operations will also increase the productivity of the production line by 5-10%.

Claims (1)

The claims An extrusion asbestos-cement mixture, including asbestos, Portland cement, a hydro-modifier - polyethylene oxide and water, characterized in that, in order to reduce waste, improve the environmental situation, increase productivity and reduce the complexity of production by increasing the pot life of the mixture, it additionally contains nitrilotrimethylphosphonic acid in the following ratio of components, wt.%: asbestos 12-14; Portland cement62-67: polyethylene oxide 0.6-0.7; water 19-24; nitrilotrimethylphosphonic acid 0.02-0.2.