CS254046B1 - Raw material mixture for the production of sulfoaluminate clinker - Google Patents

Abstract

The solution concerns a raw material mixture of sulfoaluminate clinker. The essence of the raw material mixture is that it consists of 59 to 63% by weight of limestone, 22 to 25% by weight of gypsum, 14 to 17% by weight of power plant fly ash with a content of at least 27% by weight of aluminum oxide and 10% by weight of iron oxide. The raw material mixture can be used for the production of sulfoaluminate cement with high strengths or these clinkers can be added to Portland cements and their properties can be modified in a favorable direction.

Description

The solution relates to a raw material mixture of sulfoaluminate clinker. The essence of the raw material mixture is that it consists of 59 to 63 wt. % limestone, 22 to 25 wt. gypsum, 14 to 17 wt. power plant fly ash with a content of at least 27 wt. alumina and 10% w / w; iron oxide. The raw material mixture can be used to produce high strength strength sulfoaluminate cement or to adhere to the Portland cement and to modify the properties of the cement. 254046 2540 3

The invention relates to a raw material composition for the production of sulfoaluminate clinker.

Sulfoaluminate clinkers belong to low-energy clinkers by their synthesis already at 1200 to 1250 ° C. These sims include dicalcium silicate GzS, calcium aluminate sulfate C4A3S, calcium aluminophosphite C4AF, anhydrite CS and unbound calcium oxide C at the chemical composition of the feed mixture. However, a certain minimum content of calcium aluminate sulfate phase of C4A3S is required, namely 10 to 15% by weight, sufficiently high content of CS anhydride and not too high an unbound calcium oxide content.

The highest achieved strengths of hydrated cement slurries or pastes prepared based on such clinkers range from 50 to 85 MPa. A. Müller in Silikattechnik 35, 276 1984 gives a maximum clinking strength of 85 MPa. However, particularly rapid clinker cooling is necessary. The sinter was fired at 1350 ° C for 50 min. of raw clay, anhydride, sand. According to U.S. Pat. No. 3,860,433, sinter is prepared from kaolinite, anhydride and limestone. The maximum strength is 50 MPa. Kulinova in Cement No. 7 (1982) reports a maximum strength of up to 133 MPa for high-ferrous clinker. however, these are model mixtures prepared from pure oxides. A special method was used in the tests because 93 MPa was achieved with the PC 50 comparative experiment. AO No. 225 492 discloses a sulfoaluminate bacon clinker prepared from dolomitized limestone, cement clay and gypsum. This clinker is particularly suitable for those building parts that are hydrothermally treated. AO No. 227 542 discloses a belite clinker prepared from 25 to 30 wt. cement clay, 50 to 54 wt. % limestone and 16 to 22 wt. brown sludge dropping in the electrolytic production of aluminum. Likewise, this clinker is particularly suitable for autoclave cured products. The compressive strength of the prepared bodies was about 82 MPa. According to AO number 227 541, the sulfoaluminate bacon clinker is prepared from 55 to 60 wt. limestone or dolomitized limestone, 37 to 40% by weight; cement clay and 2 to 10% gypsum. Also this clinker is suitable only for hydrothermal processing of products. 46 4

Said clinkers are prepared from high-alumina raw materials, refractory clays, kaolins, bauxites, alumina chips, which is economically disadvantageous.

The above drawbacks are eliminated by the raw material mixture for the production of sulfoaluminate clinker, which is based on 59 to 63% by weight. limestone, 22 to 25 pounds. wt. gypsum and 14 to 17 wt. power plant fly ash with a content of at least 27 wt. % alumina and 10 wt. iron oxide.

The raw material mixture according to the invention takes into account the requirements of the national economy for the raw materials to be cooked and available. Power plant fly ash is used as a secondary raw material, which positively affects the environment. The strength of the cement produced from the raw material mixture of the invention is about twice as high as that of conventional Portland cement. Another advantage of the raw material composition according to the invention is that it is fired at a relatively low temperature of about 1200 ° C. The sinter produced from the raw material mixture of the invention does not need to be cured under hydrothermal conditions as most of the belite clinker.

The composition of the feed mixture is illustrated in the example. Example

The raw material blend of 61.5 wt. limestone 15.4 wt. % fly ash 23.1 wt. gypsum

The power plant fly ash contained 29 wt. % alumina and 12 wt. iron oxide. Firing was carried out at 1200 ° C for 30 minutes and milled to a specific surface of 430 m 2 / kg.

Water coefficient! cement slurry of 0.43 and mass. saliva ratio: silica powder was 1: 2.

The strength was measured in cubes played 2 centimeters, after 28 days it was 95 MPa.

The sinters made from the raw material composition of the present invention can be adhered to conventional Portland clinkers to modify their properties in a favorable direction.

Claims (1)

PREDMET A raw material mixture for the production of sulfoaluminate clinker, characterized in that it contains 59 to 63% by weight of clinker. limestone, 22 to 25 why. wt. gypsum and 14 to 17 wt. e-YALALEZ of a brewery ash containing at least 27 wt. % alumina and 10 wt. iron oxide.