DE189833C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

- JVIl89833 -

CLASS 12 /. GROUP

HENRY NOEL POTTER in NEW YORK.

of silica.

Patented in the German Empire on July 26, 1905.

The present invention relates to the production of silicon monoxide (SiO ), which has valuable technical and theoretical properties.

When trying to melt silicon dioxide in such a way that you can get it electrically heated graphite pencil around, it has been found that if this procedure is sufficient high temperature running in

κι a room from which the air is partially withdrawn the inside of the chamber is covered with a brown powder of extraordinary delicacy. This powder is considered impure Silicon monoxide has been recognized. It was later found that the amount of silicon monoxide can be increased if the graphite pencil with a mixture of silicon dioxide and carbon, namely in that for partial reduction of the silicon dioxide The required proportions are 12 parts of carbon to 60.4 parts of silicon dioxide. Since the core itself can give off some carbon, it is beneficial to have a little more Add silicon dioxide. In practice, therefore, 12 parts become carbon and 65 parts Silica used.

It has also been found that it is not necessary to work at reduced pressure, but that silicon monoxide is also formed at atmospheric pressure, in any gas which is indifferent to the monoxide. Also, with the same success, a mixture of silicon dioxide and silicon carbide can be used, or of silicon dioxide and carborundum sand, which has recently been recognized as a mixture of silicon carbide, silicon, carbon and compounds of silicon, oxygen and carbon of the general formula Six Cx Oy . The proportions in which the mixture is produced when silicon carbide or carborundum sand is used must be determined each time by analysis and are chosen so that the ratio of bound and free carbon is only sufficient for partial reduction of the silicon dioxide. ■ If the amount of carbon is predominant, then. In general, metallic silicon is formed in addition to silicon monoxide.

If it is ensured that the silicon monoxide from the reducing field so quickly, as it is formed, it can escape, so will the complete reduction of the silica avoided.

The silicon monoxide obtained is an amorphous powder of particular fineness, most of which can swim in the water for weeks before settling on the ground.

The present process is expediently carried out in such a way that a mixture of silica and charcoal or some other carbonaceous material in the required, above-specified quantitative ratio in a closed electrical Resistance furnace accommodates in such a way that it straightens the electrical heat source (the graphite pencil) covered, thus only partially filling the oven. Then the

heating of the reaction mass Vapors rise and the vaporous silicon monoxide on the uncovered part deposit on the furnace wall as a brown powder. By evacuating the furnace before and during During the course of the reaction, the monoxide produced is even faster out of the reaction field removed. The mass produced by this process usually contains a small and

ίο varying amount of impurities that consist of carbon, silicon dioxide, silicon carbide and traces of iron and aluminum, which latter 'come from the raw material.

In an experiment in which the silicon dioxide and the carbon are particularly careful were selected, a pin made of very pure Acheson graphite was used as a heat conductor and in which the process was carried out in a partial vacuum using a hydrogen atmosphere, a product with the following composition was obtained:

SiO 91.28 percent

² S SiO ₂ 3.42

SiC 1.03

C '... 2.54 -

Fe Si ₂ 0.80

Al ₂ O ₃ , ..... 0.93

. . 100.00 percent.

That Siliciummonoxyd differs from silica in that it is much less soluble and more soluble in dilute hydrofluoric acid is in ^{i 3} S alkali metal hydroxide solution.

Furthermore, it differs from silica in that it burns in oxygen when heated and more easily from X-rays is penetrated. In a state of extraordinary delicacy, it also burns in the air, the combustion gradually going through the whole mass.

It further differs from the silicon by lower specific gravity and data by ⁴ S that approximately, the weight increases by 36 per cent when it is converted into silicon dioxide, whereas in case of metallic silicon in this case, a weight increase of approximately 113 percent is determined. It conducts electricity poorly.

Silicon monoxide is an abrasive of such hardness and fineness that it is special is valuable for polishing metal.

The powder is extremely voluminous.

The real specific gravity is about 2.24 and this implies that one large amount of air is trapped between the powder particles. The powder is therefore too a very poor conductor of heat and arguably the worst of all mineral substances existing heat conductor.

Because of its pleasant brown color and great delicacy, silicon monoxide can can be used as a dye either alone or in conjunction with other dyes. The mass can also be pressed into bricks and then firmly sintered together Mass can be burned, with or without the addition of clay or other substances for the manufacture of grinding wheels or for other useful purposes.

In a vitreous state, which often changes during the procedure described above forms, the monoxide also shows the specific gravity given above and the same chemical properties like powder; it is also hard enough to make glass scratch.

Attempts have already been made to obtain silicon monoxide by allowing a molecule of a To represent reducing agent on a molecule of silica (see reports of the Germans chemical society 23rd year p. 2657). However, since this known method to the did not lead to the desired success, it can be assumed that this did not affect the present proceedings underlying conditions were paused.

Claims (2)

Patent Claims: 1. Process for the production of silicon monoxide by incomplete reduction of silicon dioxide, characterized in that the reaction mixture is exposed in ⁹ ^ corresponding composition with the stipulation of a high electrically generated temperature in a closed chamber free of chemically active gases, that the gaseous reaction products that occur can escape from the reaction field as easily as possible. 2. Embodiment of the method according to claim 1, characterized in that ' the chamber is partially evacuated both before and during the reaction to remove the silicon monoxide produced even more quickly from the reaction field.