CS209574B1 - A method of producing lime-belitic binder - Google Patents

Abstract

Method for producing a lime-belitic binder for the production of prefabricated elements. The aim of the invention is to produce a binder from common cement raw materials as a substitute for lime, or a mixture of lime and perlite cement. It contains about 40% by weight of free CaO, about 40% by weight of beta dicalcium silicate and MgO up to 10% by weight of the rest. The binder can be advantageously used in the production of prefabricated elements by hydrothermal means and at ordinary temperatures in mixtures containing active SiO2 (slag, power plant fly ash, clay). The advantage of the binder is the homogeneous properties of CaO and the content of dicalcium silicate as a hydraulic component.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of lime-belitic binder from cementitious materials with high MgO content suitable for the manufacture of gas concrete.

So far, known methods for producing Portland cement consist of grinding natural raw materials, homogenizing with dry or wet-forming raw material, firing at 1400-1,500 ° C, and grinding the resulting wire with gypsum as a solidification regulator for Portland cement. The composition of the raw material mixture is adjusted so that minerals are formed as neoplasms after passing the raw material mixture through the sintering zone of the furnace: alite - tricalcium silicate with a variety of other substances in the form of solid solutions, bleaching - essentially dicalcium silicate, tricalciumaluminate and tetracalciumaluminateferrite. The sinter should contain at least the amount of free CaO and the content of MgO is given by the standard at 6% by weight.

After mixing with water, hydration of the individual components occurs, a solidification and curing process takes place. The hardened cement stone is made up of hydration products - calcium silicate hydrates and calcium hydroxide.

SUMMARY OF THE INVENTION The subject of the invention is a process for the production of a lime-belitic binder, which differs from the aforementioned methods of producing Portland cement, in that the composition of the raw material mixture is adjusted to be the main mineralogical constituents of the clinker after passing the raw material mixture through the sintering zone of the furnace: bleach-beta dicalcium silicate in an amount of up to 50% by weight, preferably 30-40% by weight, and free lime / CaO / in amount of 45% by weight, preferably 30-40% by weight, and calcium alumina and kaloium aluminate constituents The sinter may contain up to 10% MgO by weight.

The manufacturing process is based on raw materials traditionally used in the production of Portland cement, which are milled and homogenized dry or wet on the raw mixture. This is further burned at 1100-150 ° C, preferably at 1200 ° C, and the resulting lime-belite clinker is ground without gypsum to a lime-belitic binder. In addition, the above-mentioned operations use traditional Portland cement plants.

Because this mortar is burnt at a lower temperature than Portland clinker, the calcium component hydrates rapidly. Under suitable conditions, preferably hydrothermal, it forms with the acid / silica / tobermorite phase or tobermorite. The advantage of producing the lime-belitic binder according to the present invention is the lower firing temperature, the reduced energy requirements for the milling of lime-belite clinker, the possibility of using raw materials and a MgO content of up to 6.5% by weight in the blend and simultaneously non-homogeneity of the calcium component. The following examples will illustrate the process of manufacturing the lime-bleach compound of the present invention without limiting the scope of the invention in any way. Example 1 5 kg of limestone containing 5.95% by weight MgO was milled and homogenized with 1.1 kg of

Claims (1)

2 mentary clay, the mixture aa fired at 1200 ° C and the rapid surface cooling was measured to a specific surface area of 3,100 cm / g by Blaina. Lime-belitic binder low in composition: 39% free CaO, 37% beta dicalcium silicate, 14% calcium malate. and calcium aluminates, 9% by weight of MgO and 0.3% by weight of other admixtures. Of the lime-belitic binder, 3 cm cats were prepared with sand in a 1: 3 ratio and allowed to cure in an autoclave at 1-10 ° C under a saturated water vapor atmosphere for 8 hours. After the process, they were removed from the autoclave and tested for compressive strength . It was found to have a strength of 30 MPa. They did not contain loose lime and tobermorite and its phases were serious and avalanches. Example 2 A mixture containing 1 kg of limestone containing 3.7% by weight MgO and 0.2 kg of cementite clay was prepared. After grinding, it was dry homogenized. The mixture was fired at 1250 ° C and after rapid cooling it was ground to a specific surface area of 2900 cm 2 / g according to Blaina.Lime-belitic binder little composition: 43% 5% free OaO, 33.5% beta dicalcium silicate, 13 % calcium calcium aluminates and calcium aluminates, 6% MgO and 4% by weight of other impurities, 3 cm ewes in sand 1: 3a were prepared from lime-belite binder and allowed to cure in an autoclave at 180 ° 0 in an saturated aqueous vapor atmosphere for 8 hours, the process was removed from the autoclave. The pressure strength was determined to be 35 MPa. . The lime-belitic binder can advantageously be used as a lime and portland cement substitute in the production of gas concrete, microporous, dense concrete, in the manufacture of thermally insulating materials with fibrous reinforcement, in the manufacture of lime-sand bricks and in the subsoil posting of honest buildings. . OBJECT. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for producing a lime-binder binder characterized in that 75 to 90% by weight of the lime with a MgO content of up to 6.5% by weight is ground and homogenized with 10 to 25% by weight of cement clay. 1350 ° C for 1-4 hours and after cooling the clinker is ground to a fineness of 2500 - 3500 cm 2 / g according to the invention.