RU2187457C1 - Method of production of water glass - Google Patents

Abstract

FIELD: technology of water glass production; applicable in production of acid-proof and heat-resistant materials, production of binding agents for wood-particle boards, etc. SUBSTANCE: method includes mechanochemical activation of dry mixture of silica-containing raw materials, and sodium hydroxide. Obtained mixture is treated with water at atmospheric pressure and temperature of 80-90 C. Silica raw materials are used in form of artificial silicon dioxides, wastes of metallurgical processes and natural silica-containing minerals. EFFECT: higher efficiency. 6 cl, 1 tbl, 21 ex

Description

 The invention relates to low-temperature autoclave-free technology for producing liquid glass and can be used in the construction industry to obtain acid-resistant and heat-resistant materials, to obtain a binder in the manufacture of chipboard, silicate brick, expanded clay, etc.

A known method of producing liquid glass from a silica-containing material containing 94-96% SiO ₂ is a waste product of the production of crystalline silicon. The method includes preparing a suspension of the above waste in an alkaline solution with a concentration of Na ₂ O of 95-100 kg / m ³ at T: W = 1: (2.3-5.1) and hydrothermal treatment at 80-85 ^o C and atmospheric pressure for 2.5-3.2 hours (1. Pat. RF 2056353, Cl .: C 01 B 33/32, publ. 03.20.96).

The disadvantage of this method is the limited scope. It gives good results only when crystalline silicon wastes are used as feedstock, which are a finely divided amorphous powder with a high SiO ₂ content. When using aluminum fluoride production waste as a raw material, the method gives significant fluctuations in the yield of the finished product. When using wastes from the production of ferrosilicon or natural silica-containing materials such as sand (marshalite, diatomite, etc.), and also to process glass wastes, it is impossible to apply this method, since the interaction with alkali during heating is very slow at atmospheric pressure.

 The closest technical solution chosen for the prototype is a method for producing liquid glass, which provides for preliminary grinding of silica-containing raw materials with heated non-metallic balls, followed by the introduction of powdered alkali and water into the mill and grinding the resulting suspension to a colloid-dispersed state (2. Pat. RF 2039702, Cl .S 01 B 33/32, publ. 20.07. 95 g / prototype /).

 The disadvantage of this method is not a wide range of raw materials and high energy consumption.

 The problem solved by the claimed technical solution is to expand the range of used source silica-containing raw materials and reduce energy consumption.

The problem is solved due to the fact that in the inventive method for producing liquid glass, including mechanochemical processing of silica-containing raw materials and caustic soda, mechanically processing a dry mixture of silica-containing raw materials and caustic soda, taken in a ratio corresponding to the module of prepared liquid glass M = 1-4, when energy input into the source material 600-15000 J / g, followed by processing the resulting mixture with water at atmospheric pressure and a temperature of 80-90 ^o With a ratio of T: W = 1: (1-6), where T is a mixture of belt-containing raw materials and caustic soda after mechanochemical treatment, and W - water.

 As silica-containing raw materials, artificial silicas, natural silica-containing minerals are used - sands (pulverized silica, the so-called marshalite, diatomite, etc.), broken glass breakdown, as well as silicate block.

 The analysis of the prior art, including a search by patent and scientific and technical sources of information containing information about analogues of the claimed invention, allowed us to establish that the applicant has not found technical solutions characterized by features identical to all the essential features of the claimed invention.

 The definition from the list of identified analogues of the prototype allowed us to identify a set of essential distinguishing features (in relation to the technical result perceived by the applicant) in the claimed object set forth in the claims.

 Therefore, the claimed technical solution meets the requirement of "novelty" under the current law.

 Information about the fame of the distinguishing features in the totality of the features of known technical solutions with the achievement of the same result as the claimed, is not available. Based on this, it was concluded that the claimed technical solution meets the requirement of "inventive step".

Significant differences of the proposed technical solution in relation to the selected prototype are:
- prepare a dry mixture of silica-containing raw materials and caustic soda in a ratio corresponding to the module of the prepared liquid glass, M = 1-4;
- the prepared mixture is subjected to mechanochemical treatment, while the energy introduced into the material by balls is 600-15000 J / g;
- the resulting mixture is subjected to water treatment at atmospheric pressure and a temperature of 80-90 ^o With a ratio of T: W = 1: (1-6), where T is a mixture of silica-containing raw materials and caustic soda after mechanochemical processing, and W is water.

In the claimed technical solution, it is possible to use a fairly wide range of materials as starting silica-containing raw materials: natural and artificial silicas, including amorphous silica fume-containing wastes of metallurgical production, broken glass breakage and silicate block and to obtain liquid glass with a silicate module of 1 to 4 and density 1 , 2-1.7 g / cm ³ .

The mixture of the starting components obtained after mechanochemical treatment was subjected to hydrothermal treatment at atmospheric pressure and a temperature of 80-90 ^o C and stirring at a ratio of T: W = 1: (1-6), where T is a mixture of silica-containing raw materials and caustic soda after mechanochemical treatment, and W is water.

 The use of centrifugal planetary mills in the claimed technical solution is preferable, since they have a greater energy intensity. The grinding time of the mixture of the starting components in such mills does not exceed 3 minutes, which explains the low energy consumption in the production of liquid glass by the present method.

For the convenience of compiling a table, the claimed method uses the term "energy introduced into the material" W. By it is meant the energy transmitted by the grinding media of the activator to one gram of the processed mixture. The calculation of W, J / g was carried out according to the following formula
W = K • (M balls / M mixture) • a • t,
where is the acceleration (characteristic of the energy intensity of the activator) a = n • g;
n is a number equal to 20, 40, 60;
K is the coefficient of proportionality between the power and energy intensity of the mills; for this type of mills it is equal to 1 / 12g;
M balls - mass of balls in the activator, g;
M mixture - the mass of the mixture processed in the activator, g;
g is the acceleration of gravity;
t is the processing time of the mixture in the activator, s; then
W = 1/12 • (M balls / M mixture) • n • t.

 Examples of specific performance of the method.

Example 1 (prototype)
A portion of the charge, consisting of 200 g of artificial amorphous silicon dioxide, was placed in a porcelain ball mill. Porcelain balls preheated to 70-80 ^° C were loaded into it and the mixture was milled for 15 minutes until the crushed material passed through a 008 sieve. After this was added 300 ml of water with a temperature of 70-80 ^o C and 86 g of caustic soda. Joint grinding was carried out for 2 hours.

The energy consumption in this method for dry and wet grinding of components in a ball mill (more than two hours) is significantly greater than in the claimed method (1-3 minutes plus treatment with water at a temperature of 80-90 ^o C).

Example 2
A portion of the charge, consisting of 22.3 g of ferrosilicon waste (artificial amorphous silica) containing about 90% SiO ₂ and 8.9 g of dry sodium hydroxide (calculated on M = 3), was placed in an AGO-2 centrifugal planetary mill (200 g of balls, 40 g) and subjected to mechanochemical treatment for 1.5 min (≅ 1900 J / g). The resulting mixture was further subjected to water treatment at a ratio of T: W = 1: 4, a temperature of 80-85 ^o C and stirring for 3-3.5 hours. Received water glass with a density of 1.4 g / cm ³
All examples of the specific implementation of the method, as well as an example of the prototype are summarized in table.

 An increase in the energy load above 15,000 J / g is not economical, and a decrease in it below 600 J / g irrationally increases the hydrothermal treatment time.

 An increase in T: W above 1: 6 increases the cooking time of liquid glass, and a decrease below 1: 1 makes mixing difficult.

 Preliminary mechanochemical processing of the initial mixture with a given module (M = 1-4) in a centrifugal planetary mill can reduce the time of boiling liquid glass by several times, compared with the initial mixture.

 Compared with the prototype, the inventive method is less energy intensive and allows you to cook liquid glass from a wider range of source silica-containing substances.

Claims (6)

1. A method of producing liquid glass, including the mechanochemical treatment of silica-containing raw materials and caustic soda, characterized in that a dry mixture of silica-containing raw materials and caustic soda, taken in a ratio corresponding to the module of prepared liquid glass M = 1-4, is introduced into the original energy material 600-15000 J / g, followed by processing the resulting mixture with water at atmospheric pressure and a temperature of 80-90 ^o C at a ratio of T: W = 1: (1-6), where T is a mixture of silica-containing raw materials and caustic soda and after machining, and W - water.  2. The method according to claim 1, characterized in that the mechanochemical treatment of the dry mixture of the starting components is carried out in centrifugal planetary activators.  3. The method according to PP. 1 and 2, characterized in that as the silica-containing raw materials use artificial silicon dioxide, including waste from metallurgical industries.  4. The method according to PP.1 and 2, characterized in that as the source of silica-containing raw materials using natural minerals-sands.  5. The method according to PP. 1 and 2, characterized in that as the silica-containing raw materials use glass break.  6. The method according to PP. 1 and 2, characterized in that as a silica-containing raw materials use a silicate block.

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