SU1247373A1 - Method of producing heat-insulating articles - Google Patents

Description

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The invention relates to the manufacture of heat insulating products and can be used to produce light silicate concretes.

The purpose of the invention is to increase the strength, decrease thermal conductivity and shorten the manufacturing cycle.

The method is carried out as follows.

2/3 of quartz sand is ground in a ball mill to a specific surface of 4000, which provides the best contact between the grain, our sand and lime particles. This amount of ground sand is optimal for binding lime to calcium hydrosilicates.

Then in a paddle mixer sov-. ground sand, lime-kettle and polystyrene production waste in the form of foamed granules are mixed for 7-8.5 minutes. This time is optimal for evenly distributing the polystyrene granules in the mass and creating a homogeneous lime-sand mixture. At the same time, one third of the sand is mixed with an aqueous solution of 3% hydrochloric acid in the other paddle mixer (activating additive at the rate of 6 for 25-30 minutes). This time is optimal for activating the surface of the sand grains, i.e. increase its reactivity, which allows to accelerate the reaction of formation of calcium hydrosilicates and thereby reduce the process of heat and moisture treatment.

The use of hydrochloric acid of greater concentration leads to the destruction of polystyrene granules, and less than 3% - to an increase in the time required for stirring to activate the surface of sand grains.

Then, in the first mixer for 2-2.5 minutes, all components are mixed, after which the mass is poured into perforated molds and molded for 1-1. 4 hours - the time required to create a solid structure.

In the closed perforated form, the mixture is self-heating due to the release of energy during hydration of lime, its reaction with hydrochloric acid and the formation of calcium chloride. Warming mixture temperature

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60-80 ° C. The hydration process is accompanied by the binding of free water (thus B / T is reduced to 0.4), which leads to an increase in strength.

5 At temperatures of 70-80 ° C, polystyrene granules begin to show their reactivity, they, expanding and compacting the mixture, squeeze out excess moisture through the perforations of the forms,

0 lower B / T to 0.3-0.25. Thus, a structure is created based on expanded polystyrene granules, which have a LOW thermal conductivity.

15 Hydrochloric acid neutralizes hydrated lime to form calcium chloride, in the presence of which the solubility of free lime increases. This lime,

The 20 transition into the solution and hydrate with s is sorbed on the surface of the sand grains and already after 0.5 h after the start of the warming up, the reaction of calcium hydrosilicate begins. it's the same

25 leads to an increase in the strength of the products and reduces the time of the isothermal supply to 5 hours. Thus, the holding of products more than 1.4 hours is impractical because it does not lead to

30 to improve the properties of the molded product, on the contrary, the strength of the semi-finished product may be reduced due to excessive dehydration of the mass. Premature (up to 1 h) disclosure of these forms also leads to a decrease in

strength or destruction of the material, since the processes of hydration and dispersion of polystyrene granules may not yet be completed by that time.

40

After molding, the products possess

strength enough to heat treat them in a more stringent mode, 1.5 + 5.2 h, since the internal stress arising in the mass is transferred to the polystyrene granules and quenched, which allows a faster rise in temperature (in 1.5 h ) .d

50 . The formation of calcium hydrosilicates during heat and moisture treatment is accelerated by increasing the solubility of lime and increasing the reactivity of silica.

55 Reducing the isothermal longevity of less than 5 hours leads to a decrease in the strength of the products due to the incomplete process of formation.

3

vania low-basic calcium hydrosilicates.

An increase in the time of isothermal exposure can also lead to a decrease in the strength of the material due to the recrystallization of silicon from new growths. Thus, the total cycle time will be 9 h 57 min - 10 h 17 min. The proposed method, by eliminating the operation of sticking the products to heat and moisture treatment and shortening the autoclaving time, allows reducing the overall cycle time.

In addition, the use of the self-compaction effect of polystyrene granules and the additional activation of quartz sand makes it possible to increase the strength and reduce the thermal conductivity of the products.

According to the proposed and known methods, the samples were made and tested according to the existing method.

Example 1. 2/3 of ground quartz sand was mixed with lime and subfoam polystyrene granules for 7 minutes. In parallel, the remaining 1/3 of sand was activated in an aqueous solution of hydrochloric acid for 25 minutes. Then, in the first mixer for 2 minutes, all components were mixed, after which the mass of the pouring into the perforated form was held and held

Bulk weight, kg / cm

Compressive strength, MPa

Heat conductivity coefficient, W / m. ° С

Cycle time

VNIIPI Order 4075/24 Circulation 640

Production polygr, pr-tie, Uzhgorod ,, ul. Project, 4

2473734

It has B for 1 hour. Then the semi-finished product was dismantled and subjected to a hell-moisture treatment according to the 1.5 + 5 + 2 h regime. For example, the cycle was 9 h 57 min.

five

Example 2. The product is being prepared.

as in Example 1, 2/3 of ground sand, lime and polystyrene granules were mixed for 8 minutes, one time the quartz sand was activated for 27 minutes, mixing of all components was carried out for 2.2 minutes, the mass in perforated form was kept for 1 , 2 h. Time of the cycle 10 h 11 min.

PRI me R 3. The product was prepared in accordance with Example 1, 2/3 of ground sand, lime and polystyrene granules were mixed for 8.5 minutes, a quarter of sand was activated in an aqueous solution of hydrochloric acid for 30 minutes, stirring of all components for 2.5 minutes, at the stage of forming the mass in a perforated mold was kept for 1.4 h. The cycle time was 10 h 17 min.

The test results are shown in the table.

 As can be seen from the table, products,

0 manufactured by the proposed method have, compared to the known, the strength is 1.9 times higher, the thermal conductivity coefficient is lower by 40%, while the total cycle time is reduced by 1.8-2 times.

J

400 3.6

390 3.7

395 3.6

370 1.9

0,056 0,052 0,053 0,081 9 h 57 min 10 h 11 min -10 h 17 min 17 h 30 min

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Claims (2)

1. METHOD FOR PRODUCING THERMAL INSULATION PRODUCTS, including mixing quartz sand, lime-cap, structure-forming and activating additives, molding and heat and moisture treatment, characterized in that, in order to increase strength, reduce thermal conductivity and shorten the manufacturing cycle, 2/3 of the ground sand is pre-mixed , lime-boiling water and structure-forming additive for 7-8.5 minutes and 1/3 of quartz sand and activating additive for 25-30 minutes, molding is performed in a perforated form for 1- 1.4 hours and heat and moisture treatment - according to the regime of 1.5 + 5 + 2 hours 2. The method of pop. 1, characterized in that polystyrene production waste is used as a structure-forming additive and 3% hydrochloric acid is used as an activating additive, and ground sand is used with a specific surface area of 3800-4000 cm ² / g. Sk. ,,, ^ 1247373