RU2635309C1 - Composition of water-resistant magnesium binder with zero-deformations (versions) - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: in the version based on magnesite, the mixture includes caustic magnesite, plasticiser C-3 and modifying additives: hydrolyzed polyacrylonitrile, microsilica, soda ash. In the version based on dolomite, the mixture includes caustic dolomite, plasticiser C-3 and modifying additives: hydrolyzed polyacrylonitrile, microsilica, soda ash, magnesium oxide.

EFFECT: increased water resistance of the binder material and zero deformation of the hardening material is ensured with the use of a mineral siliceous additive, a plasticizing additive, the use of a soda ash mix as a pH regulator, using structural stresses in the hardening material of the polymerization additive hydrolyzed polyacrylonitrile as a water soluble powder.

4 tbl, 2 cl

Description

Technical field

The invention relates to the field of industrial building materials, namely to the production of waterproof magnesia binder based on caustic magnesite or caustic dolomite with zero deformation of hardening material, and can be used in dry building mixtures intended for use in certain works in residential, administrative, industrial buildings and decorative and special floors.

State of the art

A magnesian binder is known where increasing its water resistance is achieved by introducing sodium bicarbonate into the mixing liquid [RF patent 2404144], or when the product of neutralization of sulfuric acid is used as serpentinite magnesite [RF patent 2385847]. The disadvantage of these technical solutions is that the binder retains high expansion deformations during hardening of the shut binder.

Known magnesia binder with increased strength and with acceptable uniformity of change in the volume of the material, which is ensured by the manufacture and subsequent firing of granules from magnesite raw materials, in which carnallite chlorinator is added [RF patent 2404144]. The disadvantage of this technical solution is the significant complication of binder production technology.

A closer technical solution is the magnesia composition for the manufacture of water-resistant products, which is provided by the introduction of a complex additive, including slag with CaO⋅SiO ₂ content from 50 to 80 wt.%, Calcined superphosphate, magnesium sulfate, zinc oxide, plasticizer and talc [patent RF 2131857]. The disadvantage of this composition is the complexity of the composition and high expansion strains.

Disclosure of invention

The technical result of the invention is to obtain a magnesian binder for construction purposes from magnesite or dolomite with increased water resistance and zero deformation during hardening.

The increased water resistance of the binder and zero deformation of the hardening material are ensured by the use of a mineral siliceous additive, plasticizing additive, the use of a mixture of soda ash as a pH regulator, and the use of a modifying polymer additive hydrolyzed polyacrylonitrile (Gipan) as a water-soluble powder as a relaxant of structural stresses in the hardening material. As a plasticizing additive, a superplasticizer based on sulfonated naphthalene formaldehyde polycondensates is used.

In the variant of magnesia binder based on caustic magnesite, the mixture includes caustic magnesite, superplasticizer and modifying additives: hydrolyzed polyacrylonitrile, silica fume, soda ash. The mixture contains components in the following ratio, wt.%:

- caustic magnesite 90 ÷ 95

- silica fume 4.7 ÷ 1.7

- soda ash 1.3 ÷ 0.8

- hydrolyzed polyacrylonitrile 1.3 ÷ 0.8

- superplasticizer 2.7 ÷ 1.7.

As a solution of mixing, an aqueous solution of magnesium chloride is used with a mass ratio of water and magnesium chloride of 1: 1 and a mass ratio of magnesium chloride and caustic magnesite - 1: 4.

In a variant of a magnesian binder based on caustic dolomite, the mixture includes caustic dolomite, superplasticizer and modifying additives: hydrolyzed polyacrylonitrile, silica fume, soda ash, magnesium oxide. The mixture contains components in the following ratio, wt.%:

- caustic dolomite 72 ÷ 80

- magnesium oxide 19 ÷ 16

- silica fume 5.7 ÷ 2.8

- soda ash 1.1 ÷ 0.6

- hydrolyzed polyacrylonitrile 1,1 ÷ 0,6

- superplasticizer 1,1 ÷ 0,6.

As a solution of mixing, an aqueous solution of magnesium chloride is used with a mass ratio of water and magnesium chloride of 1: 1 and a mass ratio of magnesium chloride and caustic dolomite from 1: 3 to 1: 3.5.

The preparation of the mixture is carried out by mixing the components and the solution of mixing in the indicated proportions in a forced-action mixer or gravitational mixer for 3–5 min until a homogeneous composition is obtained.

The implementation of the invention Examples of the implementation of the dry mixture and working solution are shown in tables 1 and 2, respectively. The test results of the molding sand and samples made according to the developed formulation shown in tables 3 and 4 show that the problem of obtaining a water-resistant magnesia binder with zero deformations is solved.

Claims (13)

1. The composition of the waterproof magnesia binder with zero deformations, containing caustic magnesite, modifying and plasticizing additives, characterized in using hydrolyzed polyacrylonitrile, microsilica and soda ash as modifying additives, as a plasticizing additive - sulfonated naphthalene formaldehyde sulfide-based superplasticizers, this mixture contains components in the following ratio, wt.%: - caustic magnesite 90 -95 - silica fume 1.7-4.7 - soda ash 0.8-1.3 - hydrolyzed polyacrylonitrile 0.8-1.3 - superplasticizer 1.7-2.7. 2. Composition of a water-resistant magnesian binder with zero deformations, containing caustic dolomite, modifying and plasticizing additives, characterized in using hydrolyzed polyacrylonitrile, microsilica, calcined soda and magnesium oxide as modifying additives, as a plasticizing agent based on sulfonated naphtha sulfide sulfide naphtha, the dry mixture contains components in the following ratio, wt.%: - caustic dolomite 72 -80 - magnesium oxide 16-19 - silica fume 2.8-5.7 - soda ash 0.6-1.1 - hydrolyzed polyacrylonitrile 0.6-1.1 - superplasticizer 0.6-1.1.