SU50630A1 - The method of producing silicon carbide - Google Patents

Description

The industrial process for producing silicon carbide consists in heating a mixture consisting of quartz sand and carbonaceous material (with an admixture of sodium chloride and sawdust) loaded around the heater.

The products resulting from the process are arranged in zones concentric to the heater in the following order:

1. The zone of graphite formed around the heater as a result of silicon carbide dissociation is caused by my overheating.

2. The silicon carbide zone, which in turn separates into two zones, of which one is smaller, is closest to the heater, consists of relatively large crystals, while the other facing outwards consists of small silicon carbide crystals that do not form a compact mass, (Amorphous carbide) and partly second-rate material (second).

3. The zone of the siloxicon, which is a solid solution of silicon carbide and silicic acid, which is not used by itself and serves as garbage.

4. Area of sintering and unreacted charge.

From the above it can be seen that the disadvantages of the process are:

1. Partial use of a binder to obtain carbide.

2. The carbide obtained gives a significant yield of second-rate product (second) and waste (amorphous carbide and siloxicon).

3. Increased energy consumption caused by unproductive heating of the furnace, thermal insulation material, charge, etc., which is the result of periodic maintenance of the process. As a result, for 32-36 hours of operation, the furnace takes 7-8 days to simply furnace, associated with cooling, unloading and loading.

Trying to use an energy source (motor, generator, transformer, etc.) makes building a furnace battery from 6 to 8 pieces, which require significant investments in the building and furnaces.

In addition, furnace designs and work systems create difficulties in work, difficulties in mechanizing the process and unsanitary working conditions.

The proposed new method for producing silicon carbide is

administered by the latter in two (separately separated) stages: the first is reduced to the production of vaporized silicon from silica and carbon according to the equation

SiO2 + 2C Si + 2CO

the second is the synthesis of carbide by impregnating the lump or briquetted carbonaceous material with silicon vapor.

To carry out the process, the crushed mixture is heated to a temperature of 1500-2000 °, at which silicon evaporates. Heating is carried out according to the volt arc or resistance furnace.

Silicon fumes are evacuated into a chamber in which carbon material is placed in briquettes or pieces of the desired size. The chamber is heated to a temperature of 1900-2200 °, at which crystalline silicon carbide forms, and the synthesis heat of carbide is used. It is not necessary to raise the temperature at 2200 °, since the carbide dissociation will occur when passing through this limit.

Carbonaceous material as measure siliciroian :; removed from the furnace, and

a new one is provided, which can be carried out periodically or continuously. In this case, the principle of counterflow can be implemented. The proposed method allows:

1. Get dense silicon carbide in pieces of any size.

2. To realize the full use of the touch.

3. Reduce power consumption.

4. Implement a continuous process.

The latter will provide the possibility of mechanization of the process and significantly reduce the cost of equipment and further reduce energy consumption.

The subject matter of the invention.

1. A method of producing silicon carbide, characterized in that the carbonaceous material is exposed at 1900-2200 ° to silicon fumes obtained by reducing silica with anhydrous carbon at 1500-2000 liters

2. Acceptance of the method

Claim 1, characterized in that the production of silicon vapors and the treatment of carbonaceous material by them are carried out in separate furnaces of periodic or continuous action.