SU771042A1 - Method of producing crystalline seeding to cement - Google Patents

Description

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The invention relates to a technology in living materials, in particular to the production of additives to cement, increasing its strength.

The closest to the technical essence and the achieved result to the present invention is a method of obtaining a crystalline seed to cement. By burning the raw mix at 1300-1500 ° C, cooling and 10 hydration in water I.

The disadvantage of the known method of obtaining crystalline seed for cement is the low bending strength and compression of the resulting cement. five

The purpose of the invention is to increase the strength of cement.

The goal is achieved by the fact that the method of obtaining a crystalline seed for cement by burning a raw mixture at 1300-1500 s, cooling and hydration in water, provides cooling in water to 50-100 ° C to a degree of hydration of 10-15%, as well as exposure to water for 30-120 seconds. 25

The seed, the active crystalline component, is obtained by cooling the sintered portland cement clinker leaving the high temperature zone of the rotary kiln in a water

from 1300-1500 ° C to 5G-1000C. The clinker grain size should be in the range of 1-15 mm. The wet clinker is kept for 5–20 minutes in air (the time required for transportation), and then, in order to remove mechanically bound water, is dried in a drying drum at 200–400 ° C to a moisture content of 1–5%.

The duration of the contact of the hot clinker with water is 30-120 seconds. When clinker gets into water with a temperature of 1300-. At 1500 ° C, a vapor shell is formed around the surface of the grains, the vapor penetrates practically all the pores and capillaries of the grain and hydrates individual, active areas of the crystals of clinker minerals. In such hydrothermal conditions, nuclei of SchSH and xonotlite crystals are formed. The nuclei of miner xsonotlite crystals are resistant and capable of further intensive growth. The nuclei of CiSHfj crystals are metastable, but also capable of intensive growth.

During the period of aging (aging) of wet clinker before drying for 5-20 minutes, an increase in the number of active embryos occurs.

Cristianum CoSH, j and are also formed by earthenia of ettringite crystals, Ca 50d2H O and C4 AN,. The amount of crystals in this period is from 3 to 9% by weight.

During the drying period, there is a slight increase in the size of the nuclei of crystals and their number (up to 3-11% by weight), but the active state of the nuclei of crystals, their ability for intensive growth does not decrease. Crystalline hydrates ettringite,, 0, Co, SH2 at drying temperatures lose some of the water, but in such a partially dehydrated state they are characterized by even greater chemical activity.

Thus, the nuclei of crystals of hydrate compounds formed during the process of processing of Portland cement described above act as active crystalline centers capable of growth. This peculiarity of the visitor, hydrated according to the regime described above, makes it effective crystallisation. component for portland cement. Portland cement, to which, during the grinding process, 1–15% of the specified crystallization component was added, shows a 20–100% higher strength than non-additive cement. Example 1. Shchurovsky cement plant clinker and gypsum (taken in a ratio, wt.%: Clinker 95, gypsum 5) are mixed and ground in a ball mill to S 3000 cm / g. The obtained shut-in valve is filled with water (w / C 0.4) and the specimen-beams 1-1x-3 cm are molded. The storage of the samples is air-damp. Samples tested at the age of 1, 3, 7 and 28 days.

Example 2. Compounded mixed, wt.%: The clinker of the Shchurovsky cement plant is 54.5, gypsum 5, the seed is 0.5. A seed is prepared by preparing a raw mix of the following composition: S i O. - 21.0;

, - 7.0; - 3.0; CaO - 69.0 is calcined at ISOO C in a labrator silite furnace. After firing, the cake is rapidly cooled in water to 50 ° C, the contact time of the cake with water is 30 seconds. Then, the hydrated sinter is dried in a muffle with prior to removal of mechanically bound water. The degree of hydration thus obtained seed - 10%

Process preparation, sample preparation, storage and testing as described in example 1.

Example 3. Compound mixed, wt.%: Clinker of Shchurovsky cement plant - 94.5; gypsum - 5; additive - 0.5. The seed is obtained by roasting the Portland cement raw mix of the composition specified in Example 1 at 1400 ° C, by rapid cooling in water of the obtained cake from 1400 ° C to 75 ° C, followed by drying at 30 ° C to remove the mechanically bound water. The degree of hydration of the obtained seed is 12%.

Process preparation, sample preparation, storage and testing as described in example 1.

Example 4. Compound mixed, wt.%: Clinker of Shchurovsky cement plant - 94.5; gypsum 5; additive - 0.5. The seed is obtained by burning the Portland cement raw mix at 1500 ° C, by rapidly cooling the obtained cake in water to 100 ° C, followed by drying at 400 ° C until the mechanically bound water is removed. The degree of hydration of the obtained seed is 15%. The contact time of the cake with water is 120 seconds.

Production technologies, sample preparation, storage and testing as described in example 1.

The table presents the strength characteristics of the samples.

3.4 4.65.46.8

6.6 7.98,910.4

6.7. 8,19,210,1

6.2 7.08.28.4 3.2 4.06.37.9

39,048,5

54,568,2

56,080,0

45.557.0

Claims (2)

43,056.0 As can be seen from the table, the use of crystal seed allows to significantly increase the strength. Claim 1. Method of obtaining a crystalline seed for cement by roasting raw material mixture at 1300-1500s, cooling and drying, characterized in that in order to increase the strength of cement, the cooling is carried out in water up to 50-100 ° C, to a degree of hydration of 10-15 % 2. The method according to p. 1 is different and in order that the additive is kept in water for 30-120 seconds. Sources of information taken into account during the examination 1. V. Kudr Shev. Study of the properties of cement stone - reinforced with short fibrous materials. Abstract of dissertation, Ph.D., Moscow, 1973,