RU2405745C1 - Alkaline slag binder - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the industry of building materials, specifically to compositions of non-clinker binder based on boiler (coal) slag from burning coal, which may be used in making concrete and reinforced concrete articles, mortar and dry construction mixtures. The binder contains the following in wt %: gypsum dihydrate 4-8; activator - sodium or potassium hydroxide, sodium or potassium carbonate, sodium or potassium bicarbonate or mixture thereof 3-10; ash-slag mixture from burning coal containing 10.3-38.9% unburnt coal which dry cooled - the rest, and obtained by intergrinding said components to specific surface area of 700 m²/kg.

EFFECT: high strength.

3 tbl, 1 ex

Description

The invention relates to building materials, and in particular to compositions of a clinker-free binder based on boiler (stone) slag from burning coal, which can be used in the production of concrete and reinforced concrete products, mortar, dry building mixes. Known binder containing blast furnace granulated slag, liquid glass obtained from zeolite-containing siliceous rock (1). The essence of this invention is to mix the solid component of granular blast furnace slag with liquid glass. The specified binder is of low quality, brand M150. A binder of very low quality will be obtained in a mixture with blast furnace slag - this is the main drawback of a known binder.

Closest to the claimed binder is a binder containing, wt.%: Ash and slag mixture 80-95, hydrated lime 5-20, alkaline activator (relative to dry) 5-17, carried out a joint grinding of ash and slag mixture with lime to a specific surface of 4500- 5500 cm ² / g (RU 2243176 C1, 12/27/2004) (2).

The objective of the invention is to improve the quality of the proposed binder, simplifying the technology of manufacturing a binder, using cheap non-deficient components in the binder by using waste, namely, fuel slag from burning coal

The technical result is an increase in strength.

To achieve the technical result, an astringent containing an ash and slag mixture from burning coal and an alkaline activator contains as an indicated mixture an ash and slag mixture from burning coal with an unburned coal content of 10.3-38.9%, dry-cooled, and hydroxide as an activator sodium or potassium hydroxide, sodium carbonate or potassium hydrogencarbonate, sodium or potassium, or a mixture thereof, and further - gypsum dihydrate, and a joint obtained by milling said components to a specific surface of 700 m ² / kg, under the following em component ratio, wt.%:

gypsum gypsum 4-8 activator 3-10 ash and slag mixture rest.

The influence of the composition of slag and its fineness on the quality of the binder was studied.

Under optimal conditions, with the joint grinding of slag, activator and gypsum gypsum to a particle size of 700 m ² / kg and an unburned coal content of 10.3-38.9%, the binder grade is M700.

As activators use sodium or potassium hydroxide, sodium carbonate or potassium, sodium hydrogencarbonate or potassium, or a mixture thereof. Acidic potassium carbonate or sodium under standard conditions (25 ° C) - white crystalline substances with high solubility in water and high chemical activity are produced in the form of powders. Widely used in various chemical technologies. Possess low cost. The indicated properties of sodium and potassium compounds served as the basis for the development of new types of binders as activators.

When burning wood, peat, coal, large quantities of slag, ash and ash-slag mixtures are formed, which do not find qualified use. Coal slag and ash from rural and urban boiler houses are used in small quantities to fill roads. Large thermal power plants store slags and ashes in dumps and in small quantities in swamps and ravines. Disposal of this waste is one of the most acute and difficult to solve problems. The second problem is that up to 40% or more of unburned coal remains in slag.

Example. To produce a binder, ash slags of the Abagur agglomeration factory (Novokuznetsk) were used, slag compositions and their properties are shown in Tables 1, 2. Slags with unburnt coal content of 10.3% and 38.9% were used in the experiments. Slag samples were taken at the outlet of the boiler furnace, cooled in air. Wetting of the samples was not allowed (dry method). Chemical analyzes of the samples were carried out in the chemical laboratory of the Abagur agglomeration factory. A mixture of activator and slag containing 10.3% or 38.9% of unburned coal was prepared (in the table, the amount of unburned coal is indicated by pp). As an activator used alkaline waste Kemerovo chemical plant (Kemerovo), which contained 44-56% NaOH and 44-56% Na ₂ CO ₃ . Then added two-water gypsum. The prepared samples of slag mixtures with an activator and gypsum two-water were ground in a laboratory ball mill to a particle size of 700 m ² / kg. The best result was achieved when grinding mixtures to a particle size of 700 m ² / kg (table 3), when using slags with 10.3% and 38.9% unburned coal in the experiments. The quality of the manufactured binder mixtures was tested according to GOST 10178-85 “Cement. Technical conditions. " From the research results it follows that from slags containing 10.3 and 38.9% of unburned coal, with the addition of 5% activator when grinding to a specific surface of 700 m ² / kg, binders of M700 grade were obtained.

The production of the proposed binder allows you to organize the efficient use of ash slag from burning coal in boiler houses and thermal power plants and create the basis for the production of cheap binder grades from M150 to M700 with the simultaneous disposal of chemical industry waste. We consider this technology promising.

Information sources

1. Patent 2271343, С04В 7/153, 11/15/2004.

2. Patent 2243176, С04В 7/28, December 27, 2004.

Table 1 Physical characteristics of slag Type of slag Ultimate size, mm Bulk density, kg / m ³ True density, kg / cm ³ Ash with p.p.p. = 10.3% 40 745 2,38 Ash with p.p.p. = 38.9% twenty 560 2.27

table 2 The chemical composition of the slag Type of slag The content of oxides in the mineral part,% p.p.p. SiO ₂ Al ₂ O ₃ Fe ₂ O ₃ Cao MgO SO ₃ R ₂ O Ash with p.p.p. = 10.3% 61.33 20.52 9.41 3.21 2.23 0.42 1.76 10.3 Ash with p.p.p. = 38.9% 59.70 22.60 6.75 4.06 1.84 0.58 2.63 38.9

Claims (1)

A binder containing ash and slag mixture from burning coal and an alkaline activator, characterized in that it contains as the specified mixture ash and slag mixture from burning coal with an unburned coal content of 10.3-38.9%, dry-cooled, as an activator - hydroxide sodium or potassium, sodium carbonate or potassium, acidic sodium carbonate or potassium, or a mixture thereof and additionally two-gypsum, and obtained by co-grinding these components to a specific surface of 700 m ² / kg in the following ratio of components , wt.%:
gypsum gypsum 4-8 activator 3-10 ash and slag mixture rest