SU1072980A1 - Method of preparing silicate bond - Google Patents

Abstract

1. THE METHOD OF GETTING SILICATE BINDING, including the solution outside the crystalline caustic alkali in water, loading into the autoclave amorphous silica heating and holding during heating and overpressure, in order to intensify the preparation of the binder by reducing its preparation time and energy saving, as well as improvement of the strength and improvement of the blendability of mixtures, the dissolution of crystalline caustic alkali in water is performed after loading it into the autoclave simultaneously with amorphous silica emom. 2. The method of Claim 1, which is based on the fact that silicon-silica sedimentary rocks — diatomite, tripoli, spongolite, flasks — are used as amorphous silica. (L

Description

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1HE

with

00 The invention relates to a foundry, in particular to a process for the preparation of silicate binders. Wet methods are known for the preparation of soluble alkali metal silicates associated with hydrothermal and hydrobarothermal treatment of a previously prepared composition consisting of an alkaline aqueous solution and silica fl. However, the known methods are long lasting: in time, they require a considerable consumption of thermal energy and do not allow to obtain, due to incomplete dissolution of silica, as the dissolution time increases, the high binding properties of silicate bonds. The use of starting amorphous silica in the form of dusts - industrial waste in the known methods increases the time of their dissolution and informs the molding mixtures prepared on the bonding of these materials high residual strength (strength of cores or molds after pouring). The closest to the invention to the technical essence and the achieved result is a method for producing a silicate binder, which consists in the interaction of volatile dusts containing silica, and aqueous solutions of caustic alkalis at elevated temperatures and benzine pressure. According to the method, the binder is prepared in a scarcely blending operation: preformed with water & caustic caustic caustic concentration of 6-15%, load the autoclave or reactor silica in the form of industrial-. waste, then the autoclave is loaded with a prepared 6–15% solution of caustic lye, the binder is boiled with heating and 120–190 with a pressure of 2.918, 6 bar, then unloading and cooling with C23. However, this method does not provide for the use of thermal energy, and the process of dissolving a crystalline alkali in water due to its sluggishness slows down the process of 1FIGOTHOSTOUTSION soluble: 1cate is replaced by their binding properties. The purpose of the invention is to optimize the process of making communications through its shortening of its time and energy saving, as well as to ensure the efficiency of blendability of mixtures, the set goal is achieved by Tei.1, which, according to the method of obtaining strong mix, is achieved. , I turn on 11 him the crystalline caustic K1SHOOCHI in € de, loading into the autoclave Ш1 О1; fmogo cressezema, heating and vypodku under heating and overpressure, the dissolution of crystalline caustic alkali in water produced after loading it autoclave one-time with amorphous silica. In this case, siliceous sedimentary rocks such as diatolite, tripoli, spongolite, and flasks are used as amorphous silica. 1 Feminine sedimentary rocks (cop) are highly dispersed, porous material with a highly developed surface. The chemical composition of the CPC, wt.%: Amorphous silica (SiOg) 74-96 Oxides (AljOj, Fe, 0., CaO, MgOJ 3-25 Loss after proc. Alloy SPP) Remaining The specific surface area of silica sedimentary rocks is 2590 MVr . Acceleration of the binder preparation process occurs due to two factors: higher temperature in the autoclave or reactor due to heat, it dissolves when crystalline alkali is dissolved in water, and is used as an amorphous silica of siliceous sedimentary rocks, which have a more dispersed structure. The rate of dissolution of silica in water, ceteris paribus, increases with increasing temperature. At the same time, when the crystalline alkali, for example, caustic soda, is dissolved, 9940 kcal / kg per 200 water is released. This heat raises the temperature of the composition and accelerates the process of dissolving the silica if water, caustic soda and silica are simultaneously placed in any container. The binding properties of the silicate binder prepared by the proposed method are explained by the following reasons: in an alkaline medium, the solubility of silica increases significantly with increasing temperature and decreasing the size of SiO grains due to the intensive depolymerization of silica with the formation of silicate ions .. With an increase in the amount of dissolved silica bonding capacity of silicate binder (1 | it increases. On the proposed spuce, unlike the known, temperaggura of the medium is larger and the grain size it is smaller, i.e. most of the amorphous silica will go into solution in an equal amount of time. Example. Initial materials are simultaneously loaded into autoclaves, which are stainless steel closable containers.

steel and place it in a thermostat, preheated to 95 ° C, heat them for an hour, then the autoclaves are cooled and the resulting binder is removed from them. The quantitative ratio of siliceous sedimentary rocks to crystalline caustic alkali, for example caustic soda, is (1.5-10): 1, mainly ..-. (2-3): 1 wt.%, When the content of water is 30-7-0%, the mixture is treated at 85-250 ° C and pressure of 1-30 10 Pa, the cooking time is 0 ,.

In order to obtain a comparative data, silicate binders are prepared according to a method known and prototype). As an amorphous artificial silica for a known method, silica dust (kp) is used, which is a by-product of the production of crystalline silicon and is a fine, non-porous, high silica dust of the following general chemical composition, wt.%:

Total carbon 3-10 A1 .1-4

FejjOj1,5-1,6

CaO0,3-1,7

SiO,

Rest

The surface area KP is about 20,

As an amorphous silica in the proposed method using diatomite Singelia field, the average chemical composition of which, wt.%:

79.78

SiO. 6.27

, 4.01 FeaO, 1.18 CaO

MgO1.19

SOj, 0.84

PPP

The surface area of the diatomite of the Sengiley deposit is about 60.

The proposed method provides for obtaining a silicate binder with a module of 1.5-4, 0. the adjustment of the module's value is carried out by changing the 20 when loading

The ratio is --- NaOH-B autoclave or reactor, where the CPC is siliceous sedimentary, rocks, NaOH is sodium soda, taken in the dehydrated state.

The density of silicate binders obtained by the proposed method can vary in the range of 1.11, 7 g / cm. The density of the silicate binder is regulated either by changing the concentration of the silicate formations IK az O and SiO-j), or by changing the modulus Pb, oxides, KgO, etc. they increase the density somewhat more than silica), or by changing the thermodynamic parameters of the binder.

Molding mixtures are prepared with the same quantitative content of silicate binders. To test the compressive strength, samples are tested according to GOST 2189-78. The bleedability of the mixtures is determined by the strength of standard specimens under compression after heating to 1000 ° C in an oven for 30 minutes and cooling together with the oven.

In tab. Figure 1 shows the different compositions of bondings: compositions 1-3 0 cover the boundary and average values of the component ssyno relations, wt%: Amorphous silica (siliceous sedimentary rocks, cop) 30-40

5 NaOH (crystalline 10-20 Water Else Compounds 2.4 and 5 use diatomite as WB, with different dispersity — 25-EO.

0

The compositions contain as COP, respectively, tripoli, spongolit and flasks. Composition 9 was prepared according to a known method of making a binder.

five

A mixture consisting of 95% by weight of quartz sand and 5% by weight of binder was prepared.

4ejiko-mechanical and technological properties of mixtures according to

0 tab. 1 are given in table. 2

Table.:

NaOH Chrycrystalline. Xy) 20 12,5 10 50 50 12,5 12,5 12,512,5 12,5 12,5 50 50 50 50 50 50

dispersion

37.5

40 37.5

30 Physicomechanical and technological properties: i: 1, 2 of mixtures Compressive strength after blowdown with CO for 45 s. Pa, 10 10.8 12.2 0.15 0.10 Dropsiness,% Residual strength after heating to, Pa, 10 57.1 Practical Vitality, h Compressive strength after blowing CO, Pa, -WoZ, through 17.4, 17, 3 15.2 Compressive strength before blowing SD, Pa 10 C in the first state)) Fluidity before blowing Gas permeability up to 160 blowing, units. Gas permeability after purging CO2, units Adhesion to rigging after purging,% Gas workability during metal pouring, Heat resistance, C

Continued table. one

37, b

37.5

37.5 37, 5

Table 2 niz :: 15.816.7 0.160.14 65.469.7 82.4 16.3 17.2 16.7 17.5 14.7 15.2 0.080.07 0.05 87 87 79 165 175 148 30 210 e No, 2 3.2 80 595 In table. 3, depending on the order of loading the components, the properties of the mixtures are given using

KP 3.0

application of Germany) NaOH 1.0 (crystalline)

water

Diatomite 3.0 KaON 1.0 (crystalline) Water 4.0

KP - silica dust.

Table 3

1,0 0, b

95

1, Q

95 of the binder obtained from the proposed and non-known methods.

Continued table. 3

Claims (2)

1. A METHOD FOR PRODUCING A SILICATE BINDER, including dissolving crystalline caustic alkali in water, loading amorphous silica into an autoclave; heating and holding during heating and overpressure, characterized in that, in order to intensify the process of preparing the binder by reducing its preparation time and saving energy, as well as increasing strength and improving knockability of mixtures, the crystalline alkali is dissolved in water after loading into the autoclave simultaneously with amorphous silica. 2. The method according to claim 1, with respect to the fact that silica sedimentary rocks are used as amorphous silica — diatomite, tripoli, spongolite, and flasks.