RU2290373C1 - Gypsum binder production process - Google Patents

Abstract

FIELD: manufacture of building materials.

SUBSTANCE: in a method for producing gypsum binder involving crushing of crude gypsum, dehydration thereof to produce gypsum binder in presence of modifier, and subsequent grinding, said modifier is carbonate-containing water-softening sludge from heat-and-power stations mechanochemically activated by grinding jointly with superplasticizer S-3 so that concentration of the latter in modifier were 0.5-1.0%. Content of modifier in gypsum binder is 5.0-15.0%.

EFFECT: delayed setting time of gypsum binder and increased strength of gypsum stone based on binder of invention.

5 cl, 4 tbl

Description

The invention relates to methods for the manufacture of building materials and can be used in the manufacture of gypsum binders.

A known method of producing a gypsum binder by two-stage heat treatment of crushed gypsum stone with the introduction of 0.2-0.4 wt.% Additives of an aqueous solution of calcium chloride and / or sodium chloride, and / or sodium salt of naphthalenesulfonic acid (A.S. USSR No. 1511231, MKI ⁴ C 04 B 11/00, publ. 09/30/89, bull. No. 36).

The disadvantages of the method are the short setting time and low strength of the resulting gypsum binder, as well as the complexity of the technological process of its production.

A known method of producing a gypsum binder by heat treatment of gypsum raw materials, crushed to a specific surface of 3600-4000 cm ² / g, which before grinding is sprayed with 0.02-0.04% of technical lignosulfonates. In the process of heat treatment of gypsum stone at atmospheric pressure, an aqueous solution of sodium chloride in the amount of 0.2-0.5% by weight of the raw material and optionally sprayed technical ligosulfonates in the amount of 0.1-0.2% by weight of the raw material are introduced into the boiler (A. S. USSR No. 1491833, MKI ⁴ C 04 B 11/00, publ. 07/07/89, bull. No. 25).

The disadvantages of this method are the short setting time of the obtained binder, the complex technology for its production, as well as the rapid wear of equipment for cooking gypsum due to exposure to sodium chloride.

A known method of producing a gypsum binder in a digester with the addition of 0.1-0.15% of table salt (Vihter Y.I. Production of gypsum binders. A training aid for training workers in production. - M .: Higher school, 1974, p. 233-234).

The disadvantage of this method is the rapid loss of activity of the obtained binder due to increased absorption of water vapor from the air, as well as the rapid wear of digesters, the cause of which is salt.

A known method of producing a gypsum binder, including heat treatment of gypsum stone and grinding it in the presence of superplasticizer C-3 at a temperature of at least 75-80 ° C (A. C. USSR № 1784602, MKI ⁵ C 04 V 28/14, publ. 30.12 .92).

The disadvantages of this method are the complexity and high cost of technological equipment.

A known method of producing a gypsum binder, including grinding gypsum stone with the addition of superplasticizer C-3 and heat treatment at atmospheric pressure (AS USSR No. 1744074, MKI ⁵ C 04 V 11/00, 28/14, publ. 30.06.92, Bulletin No. 24 - prototype).

The disadvantage of this method is the short setting time of the resulting binder.

An object of the invention is to slow down the setting time of the gypsum binder and increase the strength of the gypsum stone based on it.

The stated technical problem is achieved in that in a method for producing a gypsum binder, including crushing gypsum raw materials, its dehydration to obtain a gypsum binder in the presence of a modifier and subsequent grinding, a carbonate-containing water softening sludge from a thermal power station combined with mechanochemically activated milling combined with superplasticizer C 3 is used as a modifier moreover, gypsum stone is used as gypsum raw material, and the grinding operation during mechanochemical activation is performed, for example, in a ball mill, This modifier and may have, for example, the following quantitative composition, wt.%:

Carbonate sludge 99.0-99.5 water softening Superplasticizer S-3 0.5-1.0

and gypsum binder can be prepared from the following quantitative composition, wt.%:

Gypsum raw materials 85.0-95.0 Modifier 5.0-15.0

The invention has the following differences from the prototype:

- a carbonate-containing sludge of water softening of thermal power plants, mechanochemically activated by grinding together with superplasticizer S-3, is used as a modifier;

- gypsum stone is used as gypsum raw material;

- the grinding operation during mechanochemical activation is performed, for example, in a ball mill;

- the modifier may have, for example, the following quantitative composition, wt.%:

Carbonate sludge 99.0-99.5 water softening Superplasticizer S-3 0.5-1.0

- and gypsum binder is obtained, for example, from the following quantitative composition, wt.%:

Gypsum raw materials 85.0-95.0 Modifier 5.0-15.0

This will slow down the setting time of the gypsum binder and increase the strength of the gypsum stone based on it.

In the patent information fund we reviewed, no similar technical solutions, as well as solutions with the indicated distinguishing features, were found.

The invention is applicable and will be used at industry enterprises in 2005-2006.

It should be noted that the applicants claim the legal protection of, above all, the qualitative composition of the composition used to carry out the method, which is reflected in the first independent claim. As for the quantitative compositions of the modifier and binder, they are in the testing phase and can be clarified depending on the quality of the individual components used, as well as when applying the claimed method in various conditions of various manufacturers.

To perform the method, the following substances were used:

- gypsum stone of the Kama-Ustinsky deposit in accordance with GOST 4013-82 with a particle size of not more than 5 mm;

- carbonate-containing sludge formed during water softening of Kazan TPP-1;

- S-3 superplasticizer manufactured by Polyplast Novomoskovsk LLC (Novomoskovsk), (TU 6-36-0204229-625-90), obtained on the basis of sodium salts of the condensation product of naphthalenesulfonic acid and formaldehyde. Table 1 presents the chemical composition of the used gypsum raw materials.

Table 2 presents the mineral composition of the used gypsum raw materials.

Table 3 presents the chemical composition of water softening sludge from Kazan TPP-1.

The method was carried out as follows.

EXAMPLE.

Gypsum raw materials (gypsum stone) are crushed to a particle size of, for example, not more than 5 mm. To obtain a modifier carbonate-containing sludge water softening TPP is dried at a temperature of, for example, 60 ° C to constant weight. Then the carbonate-containing water softening sludge of the CHPP and the C-3 superplasticizer in the ratios given as exemplary in claim 4 are subjected to mechanochemical activation by grinding in a ball mill to fineness of grinding according to the residue on sieve No. 008, for example, not more than 2%. Further, gypsum raw materials together with a modifier in the ratios given as exemplary in paragraph 5 of the claims are subjected to dehydration at a temperature of 150-160 ° C to obtain a gypsum binder.

After cooling the resulting gypsum binder to a temperature of 20 + 5 ° C, it is ground to a fineness of grinding, for example, not more than 14% of the residue on sieve No. 02.

Table 4 presents the compositions for firing according to the examples and physico-technical indicators obtained with this gypsum binders. From table 4 it is seen that the use of the claimed method allows to slow down the setting time of the gypsum binder from 6 minutes to 19-22 minutes at the beginning and from 8 minutes to 22-24 minutes at the end of setting, while the strength of the gypsum stone based on such a binder increases by 1 , 2-1.5 times compared with the strength of the gypsum binder of the prototype.

Table 1
The chemical composition of gypsum stone Content% SiO ₂ Al ₂ O ₃ + Fe ₂ O ₃ Cao MgO SO ₃ H ₂ O hydrated 0.49 0.05 32.75 0.47 46.58 19.52 table 2
The mineral composition of gypsum Content% Gypsum plaster Anhydrite Dolomite Quartz and clay minerals 92-94 4,5-5,5 1-1.5 0.5-1 Table 3
Chemical composition of water softening sludge of Kazan TPP-1 Content% H ₂ O 1.41 SiO ₂ 5.44 TiO ₂ 0,07 Al ₂ O ₃ 1.48 Fe ₂ O ₃ 5.73 MnO 0.08 Cao 42.55 MgO 4.29 Na ₂ O 0.11 K ₂ O 0.21 P ₂ O ₅ 0.16 SO ₃ - commonly. 0.37 PPP 1000 ° 39.6

Table 4
Compositions for firing and properties of the obtained gypsum binder Composition number The ratio of components,% Physicotechnical properties of the obtained gypsum binder Gypsum raw materials (gypsum stone) The modifier at a ratio of carbonate-containing sludge: C-3, wt.% Setting time, min. The compressive strength after 2 days, MPa 99.5: 0.5 99.3: 0.7 99.0: 1.0 Start end 1. (prototype) one hundred - - - 6 8 6.9 2. 95 5 7 8 10,4 3. 90 10 8 9 10.0 four. 85 fifteen 19 22 9.5 5. 95 5 6 7 9.7 6. 90 10 9 10.5 9.1 7. 85 fifteen 20.5 23 8.3 8. 95 5 5 6 9.0 9. 90 10 10 12 8.3 10. 85 fifteen 22 24 7.0

Claims (5)

1. A method of producing a gypsum binder, including crushing gypsum raw materials, its dehydration to obtain a gypsum binder in the presence of a modifier and subsequent grinding, characterized in that the carbonate-containing sludge of water softening of the thermal power station, mechanochemically activated by grinding together with C-3 superplasticizer, is used as a modifier. 2. The method according to claim 1, characterized in that the gypsum stone is used as gypsum raw material 3. The method according to claim 1, characterized in that the grinding operation during mechanochemical activation is performed in a ball mill. 4. The method according to claim 1, characterized in that the modifier has the following composition, wt.%: Carbonate-containing sludge water softening CHP 99.0-99.5 Superplasticizer S-3 0.5-1.0 5. The method according to claim 1, characterized in that the gypsum binder is obtained from the following composition, wt.%: Gypsum raw materials 85.0-95.0 Modifier 5.0-15.0