SU1719383A1 - Compound for coating porous materials - Google Patents

Abstract

This invention relates to a coating technology used to protect porous materials from adverse environmental factors. The purpose of the invention is to reduce the permeability of radionuclides by increasing the closeness of the structure of the material while maintaining its high climatic stability. The composition for the surface treatment of porous materials contains May. including: alkali metal silicate 100; alkali metal alkylsiliconate 25-720; hardener - 20% water-ethanol solution of ammonium salt from the group of fluoride, chloride, nitrate, sulfate and phosphate with an ethanol content of 20-40% 1-30; water 700-8000. The residual activity of radionuclides on the surface of the processed cardboard is 6-9%, on concrete 8-11%, the climate resistance of concrete is 97-129 cycles, the cardboard is 76-108 cycles. 2 tab. cl

Description

The invention relates to coating technology and can be used to protect porous materials from adverse environmental factors.

The purpose of the invention is to reduce the permeability of radionuclides by increasing the closeness of the surface structure of the material while maintaining its climatic stability.

Boxed cardboard and concrete are used as a porous material.

The composition is prepared as follows. Aqueous solutions of alkali metal silicate and alkali metal alkyl silicate are mixed, then a previously prepared aqueous ethanol solution of ammonium salt is added. Stirring the composition is carried out for 1 hour.

The 20% aqueous ethanol solution of the ammonium salt is prepared by dissolving 20 g of the ammonium salt in 80 g of solvent. As the solvent, a mixture of 20-40 wt.h. ethyl alcohol and 60-80 wt.h. water.

The finished composition is applied to the surface of the porous material with a brush or spray in a layer weighing 250 ± 50 g / m2 dry matter. When applying the composition to materials of the roll type, for example on cardboard, various systems of coating equipment are used.

The presence in the composition of water-ethanol solution of ammonium salt provides

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with

forming a structure from relatively homogeneous granule-like formations, which are particles of condensed alkali metal silicate in shells of condensed alkali metal alkyl silicate. A similar shell is formed on the surface of the pores of the material, which creates a coating with high surface tightness. The use of a hardener containing ethyl alcohol reduces the rate of condensation of an alkali metal alkylsiliconate with respect to the rate of formation of granules of an alkali metal silicate, i.e., provides for the condensation of alkylsilicate on the surface of alkali metal silicate granules.

The formulations of the prepared compositions are given in table. 1. As can be seen from the data table. 2 the climatic stability of the samples treated with the proposed composition is 90–170% (cardboard) and 54–103% (concrete) more than that of the samples treated with the composition according to the prototype. The residual activity of the radionuclide samples processed by the proposed composition is less than

than the samples treated with the composition of the prototype, 76-85% (cardboard) and 73-83% (concrete).

Claims (1)

Formula for surface treatment of porous materials, including alkali metal silicate, alkali metal alkali silicate, ammonium hardener and water, characterized in that, in order to reduce the permeability of radionuclides by increasing the closeness of the surface structure of the material while maintaining its climatic stability, it contains ammonium hardener 20% water-ethanol solution of ammonium salt from the group of fluoride, chloride, nitrate, sulfate and phosphate with an ethanol content of 20- 40% in the following ratio, wt.h .: Alkali metal silicate100 Alkyl metalonate alkali metal25-720 Specified ammonium hardener1-30 Water700-8000 Alkaline silicate Not: poly potassium silicate 100 lithium polysilicate sodium polysilicate Alkali metal alkali metal: mark the potassium sipoconate 25 sodium ethylsiliconate sodium methylsiliconate - potassium ethylsiliconate 20% ammonium hardener based on: ammonium phosphate 1.0 ammonium sulfate -3U ammonium fluoride ammonium nitrate ammonium chloride The amount of alcohol in the hardener20 Water 700 Tetraethylammonium chloride (201st solution) 100 - 100100100 - 100 100, Ltd. ----- - - SO 100 - - 100 --110-110 23 720 - - - -110- 110 750 110 - - 110 55 software - --20 thirty 1.0 , 0 thirty 1.0 20 1.0 5.8 35 33.3 40 20 40 1 (0 40 40 40 18 45 8000 2000 150U 2000 2000 2000 2000 2000 600 10,000 Table 1 100 thirty 5.8 1.0 35 , 0 1.0 1.0 1100 2.5 PRI mme l and e: determined by the number of freeze-thaw cycles withstand the specimens being analyzed without changing mechanical properties, and the average number of cycles for 10 tested samples is taken as an indicator of climatic stability: is determined by comparing the residual / b activity on the contaminated and washed samples, assuming that the residual activity of the untreated sample is taken as 100%, while the test samples, both processed and not treated, are contaminated with radionuclides by exposure to an aqueous solution of Cs157 N0a for 2k hours, followed by washing in a 0.15% aqueous solution of SF-24.