CS256578B1 - Raw materials' mixture for sulphoaluminate clinker production - Google Patents

Abstract

The solution concerns the raw material mixture for production of sulfoaluminate clinker using waste materials. The essence of the solution is that it consists of 58 to 63 wt. limestone, 12 to 22 wt. gypsum, 5 to 20 ° / o wt. waste from the production of rubber accelerators and 14 to 17 wt. power plant fly ash with a minimum of 7Π ° / o wt. % alumina and 10 wt. oxide iron.

Description

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

Sulfoaluminate clinkers belong to the low energy clinkers, since their synthesis takes place at 1200 to 1250 ° C. These clinkers contain dicalcium silicate C2S, calcium aluminate sulfate CjAsS, calcium aluminoferite CbAF, anhydrite CS and unbound calcium oxide C in various proportions according to the chemical composition of the feed mixture. However, a certain minimum content of C4A3S calcium aluminate sulfate base of 10 to 15 washes is required. % by weight, sufficiently high anhydride CS content and not too high unbound calcium oxide content C.

The highest strengths of hydrated cement pastes or pastes prepared on the basis of such clinkers are within the range of 50 to 85 MPa. A. Müller in Silikattechnik 35, 276 1984 gives a maximum clinker strength of 85 MPa. However, particularly fast cooling of the clinker is necessary. The clinker was fired at 1350 ^° C for 50 min. from raw materials clay, anhydride, sand. According to U.S. Pat. No. 3,860,433, the clinker is prepared from kaolinite, anhydride and limestone. The maximum strength achieved is 50 MPa. Kulinova in Cement no. 7 (1982) gives for ferrous clinkers. maximum strength up to 133 MPa, but it is a model mixture when prepared from pure oxides. A special method was used in the tests because the comparative experiment with PC achieved 93 MPa. AO č. No. 225,492 discloses sulfoaluminate-belite clinker prepared from dolomite limestone, cement clay and gypsum; This clinker is particularly suitable for components that are hydrothermally processed. In AO no. No. 227,542 discloses a belite clinker prepared from 25 to 30 wt. 50 to 54 wt. % of limestone and 16 to 22 wt. brown sludge falling off in the production of aluminum. This clinker is also suitable for autoclave-cured products. The compressive strength of the prepared bodies was about 82 MPa. Podta AO č. 227 541 is a sulfoaluminate-belite clinker prepared from 55 to 60 wt. % of limestone or dolomitated limestone, 37 to 40 wt. cement clay and 2 to 10% gypsum. This clinker is also suitable only for hydrothermal processing of products.

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

These drawbacks are overcome by the raw material composition for the production of sulfoaluminate clinker, which consists of 58-63% by weight. limestone, 12 to 22 washes. wt. gypsum from 14 to 17 wt. of fly ash with a content of at least 27% by weight % alumina and 10 wt. % ferric oxide and 5 to 20 wt. solid wastes from the manufacture of rubber accelerators with a sulfur content of 2 to 25% by weight;

The raw material mixture according to the invention takes into account the requirements of the national economy to keep the raw materials available and available. Power ash is used and waste pitches such as solid waste from the production of rubber accelerators are used. pitch of the gudron type.

The consumption of these secondary raw materials positively affects the environment.

The strengths of the cement produced from the raw materials of the composition of the invention exceed the strengths of the cement slurries produced on the basis of conventional Portland cement. A further advantage of the feedstock composition of the invention is that it is fired at a relatively low temperature of about 1200 ° C and the calorific content of the solid waste ... reduces ... the consumption of primary fuels.

The composition of the raw material mixture is illustrated by way of example.

Example

Raw material composition

61.5 wt. limestone

15.5% w / w ash

18.5% wt. gypsum • 10.5 wt. pitch

The fly ash contained 29% by weight. % alumina and 12 wt. iron oxide. The pitch contained 20 wt. sulfur.

The firing was carried out at 1200 ° C for 30 minutes and ground to 480 m ² / kg.

The aqueous cementitious slurry was 0.43 wt. the clinker: silica sand ratio was 1; Second

Strength was measured in 2 c cubes and after 1 day was 21 MPa and after 7 days was 46 MPa.

Claims (1)

SUBJECT Raw material mixture for the production of sulfoaluminate clinker, characterized in that it consists of 58 to 63 wt. % limestone, 12-22 wt. gypsum, 5 to 20 wt. waste from the manufacture of rubber accelerators with a sulfur content of 2 to 25% by weight % of the gudron type pitch and 11 to 17 wt. of fly ash with a content of at least 27% by weight % alumina and 10 wt. iron oxide.