SU948881A1 - Process for producing highly-dispersed silicon dioxide - Google Patents

Description

 The invention relates to the field of production of highly dispersed silicon dioxide and can be used in hsggy. industry and in other branches of the national economy using active highly dispersed fillers, rubber amplifiers, thickeners, etc. A method is known for producing highly dispersed silicon dioxide, which involves burning a mixture containing trichlorosipane vapor and hydrogen and oxygen-containing gases in a torch at a temperature of 1050 ° –10 ° C, cooling of the products of crust containing silicic acid in the form of an aerosol, and separation of the last coagulation from the adsorbed impurities in a known manner. Combustion is carried out in the presence of a nitrogen carrier gas, Cl. However, with the addition of an additional inert component to the reaction zone, which is not part of the chemical composition of the final product and requires significant first energy consumption to heat up to the reaction temperature, the efficiency of the silica production method decreases. There is also known a method involving burning a mixture containing silicon tetrachloride, hydrogen and oxygen-containing gases in a torch at 11.00-140 ° C, cooling the reaction products and separating the target product 2. A disadvantage of the known method is to operate the process at high temperatures, increased consumption of natural gas, Equation with that which is necessary according to the glass measurement of the reaction SiCe + 2Hg-fO, 2 SiOQ + 4HCe, as well as the trouble of adjusting the temperature in the flame zone (burning zone) to an accuracy of 1 ° C by changing the composition gas and / or flow rate of the reaction mixture from the burner nozzle. The purpose of the invention is to reduce the process temperature and hydrogen consumption, as well as to ensure the possibility of regulating / heating the temperature with an accuracy of 10-15 ° C.

The delivered chain is achieved by the fact that the initial components of the reaction mixture are subjected to an electric field of 15O-17O kV before being introduced into the combustion zone.

The essence of the invention is that the initial components of the reaction mixture, including, for example, Si C P, Jrlq, Of, before being introduced into the α-combustion zone, are subjected to atomization and / or ionization O in a high electric field.

The technology of the method is as follows.

The starting components are tetrachloride and silicon, hydrogen and oxygen are dropped into the combustion zone along three lines without preliminary displacement. At a distance of, for example, 55 cm from the inlet pipe into the reaction furnace, the gas flows of the initial components of the reaction mixture moving through the high-voltage electric field, each of the gases being atomized and / or 25 V to a given volume ratio ) downgraded. The degree of atomization or ionization of each of the initial components of the reaction mixture is governed by the strength of the electric field, the mass flow of gases and the design features of the device.

The table below presents the comparative characteristics of silicon dioxide, obtained from the known and

the proposed methods, and the main parameters of technological processes.

The degree of atomicization or ionization (usually these processes exist together) when processing the initial components of the reaction mixture in a high voltage field depends primarily on the strength and geometry of the high voltage electric field.

The initial components of the reaction mixture, which exist in the gaseous state, pass the high voltage field and are capable of destroying intramolecular bonds and subsequent separation of electrons, leading to the existence of a substance in the ionized state.

Atomization (ionization) of the source components allows them to be prepared for the hydrolysis reaction, i.e., the process starts in the combustion zone not at a molecular, but at an atomic or ionic level, as a result of which the temperature of the flame zone (combustion zone) can be lowered. from 1100 to, and the consumption of hydrogen fuel is reduced by 19% without reducing the product quality.

In addition, temperature regulation increases with an accuracy of 10-15 ° C, as a result of which aerosil may be obtained with a high degree of structure uniformity and dispersion.

The main parameters of the process

1100 109О

1OO

20 25 Not more than

Technical characteristics of the obtained Aerosil

i

364.5

364

5-20

5-20

930

930

980

1000

78

81 78

92

10-15

397

397

385

375

5-12

4-10

4-10

5-15

Si On content

%

Content

oxides

TiOrj -Ae O -Fe Oj,%

pH of water suspension

Claims (1)

1. USSR author's certificate NS 4572О8, cl. C O1 B 33/18, 19752. Manchenko L.V. Aerosil, its properties, application and technical conditions, Lviv, Kamen r, 1965, p. 6