SU1266843A1 - Method for heat and moisture treatment of lime-siliceous articles - Google Patents

Abstract

METHOD OF HEATING-WETTING TREATMENT OF LIMESTONE-SILICA PRODUCTS OF Autoclave hardening, including pressure rise up to 1011.5 bar and temperature up to 183-187 C for 1.5-2 hours, first holding in saturated vapor for 1-3 hours, after that superheated steam with a temperature of 200-230 ° C for 10-15 hours, a decrease in pressure and temperature within 1.5-2 hours, about the fact that, in order to reduce shrinkage and residual moisture of products and increase the content of tobermorite in them , exposure in the first medium of superheated steam is made (L at a pressure of 7.5-8.5 atm.

Description

This invention relates to a technology for the manufacture of heat insulating products, in particular silicate products, for example: lime-silica; autoclave hardening with large initial water quenching, and can be used in the production of building materials for industrial and heat-and-power construction.

The purpose of the invention is to reduce shrinkage and residual moisture of products and increase the content of tobermorite in them.

The method is carried out in the following sequence.

A finely dispersed asbestos-containing lime-floater mixture with a water-hard ratio В / Т - 6.0 is prepared, which is poured into molds and loaded into a special autoclave equipped with a heat exchanger and ventilation device. The heat exchanger ensures the supply of heat during the period of treatment in the environment of superheated steam, and the ventilation system provides uniform circulation and supply of heat to the m-treated products.

After loading the molds with the mass and closing the autoclave, saturated steam is fed under pressure, the time of pressure rise to 10-11.5 atm and temperature up to 183-187 ° C is 1.5-2.0 hours. The products are held in HacbmjeHHOro environment A pair of 13 4JB process of holding the product is gaining sufficient structural

strength and, in addition, during this time, complete bonding of lime to silica berry is provided. Then the supply of saturated steam is stopped, a heat exchanger is turned on, steam is supplied to it (P 36-39 MPa, t 310360 ° C), and a ventilation unit providing drying mode under pressure of 7.5-8.5 MPa at 200-230 ° C with superheated steam for 10-13 hours. After that, reduce the pressure and temperature in the autoclave for 1.5-2 hours.

In such a transition from the treatment with the steam supply at a pressure of 11.5 bar to the drying with superheated steam, the pressure of 8.0 bar after the supply of saturated steam is shut off, the pressure is drastically reduced from 11.5 bar to 8.0 bar for 3-5 minutes, which contributes to the abrupt removal of moisture from the products, as well as to the temperature gradient gradient between the products and the medium already at the beginning of drying.

The condensate is discharged from the autoclave during the supply of saturated steam. The superheated steam generated from the moisture of the products is continuously removed through a plug that is automatically adjustable.

Modes of heat and humidity treatment by a known method and heat and moisture treatment of lime-silica products of the proposed method are given in table. one.

. The results of product tests are presented in Table. 2

Table 1

Pressure rise to 11.5 atm; saturated steam supply, h

Vyderzhka in the environment of saturated steam of 11.5 ati,

Pressure drop from 11.5 to 8.0 MPa, min

Sud1ka with superheated steam t 220 ° C, at a pressure of 8.0 hours atm

12 10

15

11.5 ati

Total duration of heat and humidity treatment, h Bulk mass (in a dry state), kg / m 180-185 179-18 Flexural strength, kgf / cm 3.7-4.1 4.3 Residual humidity (absolute),% 65 -70 Linear shrinkage at% 1.75-1.9 1.37

Heat conductivity coefficient, kcal / m.h. WITH

at 25 C

125 ° С

zoo

The content of low-base calcium hydrosilicate (tobermorite) in the lime-cream: non-earthy 1 in a twitch,%

The long table.

1615

18

Tabli.ca2 27-30

0.05 0.05 0.056 0.055 0.063 0.062

70-75

-80

75-80 175-180 4.0 35-40 1.45

Claims (1)

METHOD OF HEAT AND WET TREATMENT OF Lime-SILICA autoclaved hardening products, including pressure increase up to 10- 11.5 ati and temperatures up to 183-187 C for 1.5-2 hours, exposure · first in a saturated steam environment for 1-3 hours, then superheated steam with a temperature of 200-230 ° C for 10-15 hours a decrease in pressure and temperature for 1.5-2 hours, which consists in the fact that, in order to reduce shrinkage and residual moisture of the products and increase the content of tobermorite in them, exposure to superheated steam in the medium is carried out at a pressure of 7.5 8.5 ati.