RU2564429C1 - Raw mix for obtaining of plaster materials - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: raw mix for obtaining of gypsum materials includes semi-water gypsum, water and complex reinforcing additive consisting of aluminium sulphate and calcium hydroxide at the following ratio of components, wt %: semi-water gypsum 62.400-62.450, aluminium sulphate 0.0280-0.1123, calcium hydroxide 0.046-0.047, water - the rest.

EFFECT: increase of strength of gypsum stone at simplification of technology.

Description

The invention relates to gypsum materials used in the manufacture of thin-walled products for construction purposes, for example wall panels without cardboard sheathing, dry plaster, etc.

Known raw mix for building materials containing semi-aquatic gypsum, quartz sand, a mixture of synthetic detergent and polyvinyl alcohol in a ratio of 1: 1, phosphoric acid and magnesium and / or aluminum silicate and water containing, wt.%:

semi-aquatic gypsum 39.4-51.4 quartz sand 0.6-20.4 magnesium and / or aluminum silicate 0.6-9.5 foaming agent 0.1-0.7 orthophosphoric acid 0.6-1.3

(RU No. 2280627, Cl. C04B 28/14, 04/04/2005).

The disadvantages of this invention are the low strength of the products in bending, the need to use an external coating, such as cardboard, the presence of an excessively large number of components that complicate the manufacturing process.

The closest in technical essence is the raw material mixture for the manufacture of gypsum products containing semi-aquatic gypsum, slaked lime, Portland cement, silica sand, water, zinc sulfate, mullite-siliceous wool, in the following ratio, wt.%:

semi-aquatic gypsum 20 - 30 slaked lime 1.2 - 1.5 Portland cement 0.3 - 0.5 quartz sand 41.97 - 47.95 water 20 - 23 zinc sulfate 0.03 - 0.05 mullite-siliceous wool 2.5 - 3.0

(RU No. 2 415 098, Cl. C04B 28/14, 03/27/2011).

The disadvantages of this invention are low strength, manufacturing complexity and expensive components.

The objective of the invention is to develop a raw material mixture having self-reinforcing properties to obtain gypsum materials,

The technical result of the invention is to increase the strength of gypsum stone while simplifying the technology.

The task and the technical result are achieved in that the raw material mixture for the production of gypsum materials includes semi-aquatic gypsum CaSO ₄ · 0.5H ₂ O and water. According to the invention, the raw material mixture further includes a complex reinforcing additive consisting of aluminum sulfate Al ₂ (SO ₄ ) ₃ and calcium hydroxide Ca (OH) ₂ , in the following ratio, wt.%:

semi-aquatic gypsum 62,400 - 62,450 aluminum sulfate 0.0280 - 0.1123 calcium hydroxide 0.046 - 0.047 water rest

The increase in the strength of the gypsum composite is achieved by introducing a complex reinforcing additive into the composition of the raw material mixture.

The reinforcing additive provides gypsum with additional structural bonds, which favorably affects the structure formation of the material and improves the strength of the finished product.

Aluminum sulfate and calcium hydroxide in the composition of the raw material mixture provide conditions for the formation of ettringite in the initial stages of crystallization. Having a fibrous structure, ettringite at the molecular level reinforces the gypsum matrix and, thereby, increases the strength of the hardened material.

With the introduction of aluminum sulfate in the composition of the raw material mixture of less than 0.0112 wt.% - the structural phase state of the material does not reach optimal parameters, therefore, strength and density do not reach optimal values. The introduction of aluminum sulfate of more than 0.0280 in wt.% Will reduce the strength of the structure due to the formation of excess ettringite, which leads to disruption of the structure of gypsum stone.

With the introduction of calcium hydroxide less than 0,046 mass% does not provide conditions for the formation of the crystalline structure of ettringite. On the other hand, with the introduction of calcium hydroxide of more than 0.047 wt.%, The formation of a gypsum stone with a defective structure will occur.

Varying both factors allows you to get the optimal composition of gypsum material.

Using the proposed composition helps to reduce energy and labor costs for the homogenization of the mixture. Additionally, the number of components in the composition of the proposed mixture is reduced, which greatly simplifies the technology.

The task is also achieved by selecting the optimal content of complex additives in the composition of the raw mix, as well as water-solid ratio.

The raw material mixture for obtaining modified gypsum composites is obtained as follows.

Example 1

The calculation of the number of solutions that make up the complex reinforcing additive for kneading gypsum dough was carried out based on their stoichiometric amounts.

To prepare the raw mix, the components were mixed manually for 1 minute.

The samples were molded by injection technology. Gypsum samples were hardened at normal temperatures and humidity after 2 hours and after 7 days.

The preparation of a raw mixture of self-reinforcing gypsum materials is illustrated by the following examples.

The mixture was prepared using the following ratio of components, wt.%:

semi-aquatic gypsum 62,400 aluminum sulfate 0.0280 calcium hydroxide 0,046 water 37,526

During the experiment of the raw material mixture to obtain gypsum materials, the following results were obtained: strength - 6.92 MPa at a density of 1048 kg / m ³ .

Example 2 (composition)

The mixture was prepared similarly to the above example, but the following ratio of components was used, wt.%:

semi water gypsum 62,450 aluminum sulfate 0.1123 calcium hydroxide 0,047 water 37,3907

During the experiment of the raw material mixture to obtain gypsum materials, the following results were obtained: strength - 5.35 MPa at a density of 1078 kg / m ³ .

Example 3 (composition)

The mixture was prepared similarly to the above example, but the following ratio of components was used, wt.%:

semi-aquatic gypsum 62,429 aluminum sulfate 0,0560 calcium hydroxide 0,047 water 37,468

During the experiment of the raw material mixture to obtain gypsum materials, the following results were obtained: strength - 10 MPa at a density of 1060 kg / m ³ .

Experimental laboratory tests were carried out in the laboratory of the department "Production of building products and structures" of Tver State Technical University. The following positive results were obtained: when the content in the composition of the raw material mixture by mass% of aluminum sulfate Al ₂ (SO ₄ ) ₃ was 0.0560 and calcium hydroxide Ca (OH) ₂ was 0.047, the strength of the gypsum stone reached 10 MPa, which is 53% higher than the strength of gypsum stone without the addition of aluminum sulfate and calcium hydroxide; the density is 1060 kg / m ³ . In the production of gypsum materials, there is a reduction in cost due to a reduction in the number of components in the composition of the proposed mixture, as well as a reduction in energy and labor costs for the homogenization of the mixture.

Claims (1)

A raw material mixture for the production of gypsum materials, including semi-aquatic gypsum and water, characterized in that it further includes a reinforcing additive in the form of aluminum sulfate Al ₂ (SO ₄ ) ₃ and calcium hydroxide Ca (OH) ₂ , in the following ratio, wt.% :
semi-aquatic gypsum 62,400 - 62,450 aluminum sulfate 0.0280 - 0.1123 calcium hydroxide 0.046 - 0.047 water rest