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Method for producing pyrogenic silica

A technology of fumed silica and dichlorosilane, used in silica, silica, chemical instruments and methods, etc., can solve problems such as harmful ignition, and achieve the effect of stable production start and stable production

Active Publication Date: 2019-08-16
WACKER CHEM GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Second, these deposits are more easily dislodged from the walls and entrained by the vortex in the mixing element, and can lead to harmful ignition before entering the reaction chamber

Method used

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  • Method for producing pyrogenic silica
  • Method for producing pyrogenic silica
  • Method for producing pyrogenic silica

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0098] Embodiment 1: comparative embodiment (not the present invention)

[0099] Substance stream b is a silane mixture from industrial scale production with a composition comprising

[0100] 63.7vol.% silicon tetrachloride,

[0101] 8.0vol% trichlorosilane,

[0102] 28.1vol% dichlorosilane and

[0103] 0.2 vol% of monochlorosilane.

[0104] Due to the preparation, the silane mixture may contain small amounts of impurities (eg boron chloride, aluminum chloride or hydrocarbons, or further silanes (up to 0.1 vol %)).

[0105] The silane mixture is converted into a gaseous state in the silane evaporator and passed through as image 3 The pipe connections shown in are introduced at a temperature of 105° C. into an air stream (substance stream d) at a temperature of 105° C. in the mixing chamber without premixing with substance stream a. Substance stream a consisting of natural gas and hydrogen is introduced separately into the mixing chamber M at a temperature of 105° C. via ...

Embodiment 2

[0110]Substance stream b is a silane mixture from industrial scale production with a composition comprising

[0111] 63.7vol% silicon tetrachloride,

[0112] 8.0vol% trichlorosilane,

[0113] 28.1vol% dichlorosilane and

[0114] 0.2 vol% of monochlorosilane.

[0115] Due to the preparation, the silane mixture may contain small amounts of impurities (for example, boron chloride, aluminum chloride or hydrocarbons, or further silanes (up to 0.1 vol %).

[0116] The silane mixture is converted into a gaseous state in the silane evaporator, and passed through as figure 1 The pipe connection shown is in contact with stream a consisting of natural gas and hydrogen heated up to 105° C. upstream of the basket filter in order to achieve 93.2 parts by weight of silane and 6.8 parts by weight of fuel gas (substance stream c). Based on its mass, the ratio of hydrogen to natural gas is 1:1. The mixture from the basket filter is introduced at a temperature of 105° C. into a mixing cham...

Embodiment 3

[0121] Embodiment 3 (the present invention):

[0122] Substance stream b is a silane mixture from industrial scale production with a composition consisting of

[0123] 63.7vol% silicon tetrachloride,

[0124] 8.0vol% trichlorosilane,

[0125] 28.1vol% dichlorosilane and

[0126] 0.2 vol% of monochlorosilane.

[0127] Due to the preparation, the silane mixture may contain small amounts of impurities (eg boron chloride, aluminum chloride or hydrocarbons, or further silanes (up to 0.1 vol %)).

[0128] The silane mixture is converted into a gaseous state in the silane evaporator, and passed through as figure 1 The pipe connection shown is in contact with a substance stream a consisting of natural gas and hydrogen heated to 105° C. in a basket filter, so that 93.2 parts by weight of silane and 6.8 parts by weight of fuel gas are obtained (substance stream c). Based on its mass, the ratio of hydrogen to natural gas is 1:1. The basket filter is equipped with 2 separate inlets...

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Abstract

The problem addressed by the invention is that of developing an economical method for producing pyrogenic silicas in which silicon compounds with low ignition temperatures can be used as the startingmaterial without ignition occurring in the mixing chamber of the burner before entry to the burner nozzle. In addition, the described problem of the formation of extremely flammable or pyrophoric coatings is minimised. This problem is solved by the provision of a method for producing pyrogenic silica in which a material flow a, containing at least one combustion gas, is combined with a material flow b, containing at least one silane selected from the group consisting of dichlorosilane (H2SiCl2), monochlorosilane (H3SiCl) or monosilane (SiH4) or mixtures thereof, to form a material flow c without using a static or dynamic mixing element; and in which material flow c is fed to a material flow d, containing at least one oxygen source; material flows c and d are mixed using a mixing element toform a material flow e; material flow e is introduced into a reaction chamber, ignited and reacted; and the resulting solid is separated out. The invention also provides a device for carrying out themethod. The method according to the invention allows pyrogenic silicas to be produced from silicon compounds having low ignition temperatures without premature ignition occurring before these starting materials enter the burner nozzle. The formation of extremely flammable or pyrophoric coatings is minimised. The device according to the invention allows this method to be carried out optimally.

Description

technical field [0001] The invention provides a method for producing fumed silica, wherein a material stream a comprising at least one fuel gas is combined with at least one material selected from the group consisting of dichlorosilane (H 2 SiCl 2 ), monochlorosilane (H 3 SiCl) or monosilane (SiH 4 ) or mixtures thereof, the material stream b of the silane in the group combines to provide a material stream c without the use of static or dynamic mixing elements, and wherein the material stream c is fed to a material comprising at least one oxygen source Stream d, material streams c and d are mixed using a mixing element to provide material stream e, which is introduced into a reaction chamber where it is ignited and converted and the resulting solids are removed. The invention further provides devices for carrying out the method. Background technique [0002] Fumed silica is obtained from gaseous oxidizable and / or hydrolyzable silicon compounds, usually silanes or silane ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/18
CPCC01B33/183
Inventor 马塞尔·萨拉蒙
Owner WACKER CHEM GMBH