CS226307B1 - Portland clinker firing composition - Google Patents

Description

The invention relates to a raw material mixture for firing Portland clinker.

There is a known raw material mixture for firing Portland clinker consisting of limestone, crushed blast furnace slag and steel slag. The use of iron ore concentrates in metallurgical plants decreases the alumina content of the lump slag and thus reduces the content of components which increase the reactivity of the feedstock, thereby greatly deteriorating the burnability of the feedstock mixture. In order to improve the care of the raw material, increase the rotary kiln performance and reduce the specific fuel and electricity consumption, lime saturation has been reduced, so that the raw material mixture consists of the following weight ratio: 56 to 58% limestone, 32 to 33% crushed blast furnace slag. 11% of the steel slag, with the lime saturation of this raw material Kg β = = 78, the silicate modulus M = 2.1 and the aluminate modulus M _A = 0.96. The clinker produced from such a raw material has a low content of tricalcium silicate and tricalcium aluminate, and the cement produced therefrom has lower initial strengths and also a slow increase thereof.

These drawbacks are overcome by the raw material composition according to the invention, which consists in that it consists in a weight ratio of: 53 to 80% of limestone, 15 to 33% of crushed blast furnace slag, 3 to 10% by weight. steel slag and from 1 to 10% of chamotte waste after wear of industrial furnace linings.

The use of chamotte waste after wear of the furnace linings as a component of the Portland clinker rinse feedstock will increase the alumina content of the aurovine mix and thereby increase its reactivity and improve the burnability. The alumina is present in fireclay in the form of mullite - 3Al ₂ 0 ₃ . 2Si0g, silimanite - Al ₂ O 4. SiO ₂ , or as corundum - nAl ₂ O 4.

Although they are stable compounds, anortite - CaO is formed from contact with high-alkaline substances and melt rich in calcium oxide. Algo ^ · 2 SiO ₂ and especially gehlenite - 2CaO. AlgOj. SiO. The newly formed compounds form low melting eutectics with each other and with clinker minerals, e.g. 2CaO. AlgO-j. SiO ₂ - CaO. AlgO-j. 2SiOg - CaO. SiO 2 - 1265 ° C, or 2 CaO. AlgO-j. SiOg - 2Ca0. SiOg - CaO. SiOg - 1380 ° C and the like, thereby increasing the amount of melt, decreasing the temperature of its formation and thereby increasing the reactivity of such a raw material mixture.

In particular, the advantages of the raw material mixture for firing Portland clinker according to the invention are:

increasing the reactivity of the raw material mixture

- possibility of production of clinker with higher content of tricalciumsilicate and tricalciumaluminate and thus with higher initial strengths and their faster growth

- increasing the power of the rotary kiln and reducing specific fuel and electricity consumption

- possibility to choose in advance 3 qualitative parameters of the raw material mixture (eg lime saturation, silicate and aluminate module) compared to 2 · and 3-component mixture

- the recovery of industrial waste, which is not used and occupies large areas of agricultural land, which will improve the environment for its deposit.

The calculated amounts of the individual components of the Portland clinker firing composition according to the invention are continuously metered into the raw mill, where they are simultaneously ground and partially homogenized. After grinding and homogenization, we get raw meal prepared for burning of Portland clinker.

Example

The following parameters were qualitatively entered for the 4-component raw material mixture for firing of Portland clinker: lime saturation K _SLp = 97, silicate modulus Mg = 2.3 and aluminate modulus M ^ = 1.7. The raw material mixture with the following parameters is composed in a weight ratio of: 62.27% of limestone; 26.35% crushed blast furnace slag; 6.24% ooeliar slag and 5.14% refractory waste - labeled mixture A.

To compare reactivity and palpitability, a 3-component feed mixture with a lime saturation ^K gLp = 96 and a silicate modulus Mg = 2.3 was calculated in a weight ratio of: 55.08% limestone; 33.8% crushed blast furnace slag and 11.04% steel slag. The aluminate modulus = 0.79 - designation mixture B was calculated for the ratio of the individual components.

Both feed mixtures were subjected, after milling and homogenization, to a heating microscope and differential thermal analysis under the same conditions. From the heating microscope, the sintering starts were determined for mixture A-1170 ° C and for mixture B-1225 ° C.

Differential thermal analysis yields endothermic minima temperatures that characterize the fluid phase formation in the feedstock mixture for mixture A-1360 ° C and for mixture B-1400 ° C. Thus, the 4-component feedstock mixture for Portland clinker firing containing refractory clay starts to sinter and form a liquid phase at lower temperatures than the feedstock without this additive, and thus is more reactive and less flammable. Average chemical composition of individual components of the raw material mixture in mass. % is given in the table:

CaO SiO A1 ₂ O ₃ ^Fe 2 ° 3 limestone 54.0 0.8 0.3 0.2 crushed slag 44.5 40.0 7.4 1.2 ocelarska soska 32.5 16.7 3.45 30.0 fireclay 2.0 60.0 35.0 2.5

226,307th

The raw material for Portland clinker firing according to the invention can be used in all Portland clinker firing plants, especially near plants where there are enough of its individual components.

Claims (1)

OBJECT OF THE INVENTION The raw material mixture is fired by Portland clinker, characterized in that it consists of 53 to 80 wt. limestone; 15 to 33 wt. crushed blast furnace slag; 3 to 10 wt. % of steel slag and from 1 to 10 wt. fireclay selected after wear of the lining of industrial furnaces.