SU56111A1 - Tube for introducing oxygen into the liquid metal - Google Patents

Description

The practice of ferrous metallurgy begins to include the injection of pure oxygen into the molten metal. For this, it is necessary to have a pipe that would be able to withstand very difficult working conditions (abrupt temperature change, the effect of slags at temperatures up to 2000 ° rich in FeO; the presence of free oxygen).

Offered for this purpose tubes made of graphite, protected inside by quartz, quickly burn down and by themselves the roads.

The tube according to the invention is characterized in that its outer refractory coating is made of a mass consisting of a mixture of magnesite, alumina and coal.

Recipe masses

Magnesite Alumina CoalSpeed of burning

30% 30 "/ v40 / ,, 1,5 CM per minute

. .

50/50 / o3 e. And in minutes

. .

60% -40 / (, 2 ate per minute

. .

At the direction of the inventors, coal burns in oxygen only on the surface and slags dissolve the mineral part also from the surface. Therefore, both of these processes are very slow.

A glass tube is inserted into an iron tube cut from one end to the stack. The space between the two tubes — iron and glass — is tightly packed into powdered and sifted metallurgical magnesite. To prevent the latter from spilling out, the lower end of the pipe is smeared with a slurry of magnesite powder and soluble glass. On iron pipe, bu is suggested to impose the following masses:

Coal - electrode pitting or conventional technical graphite, the ash content of which does not exceed, is ground to a powder. The granulometric composition of the powder is determined by sieving through a sieve of 4000 holes per cm, and screening of the finer fraction is unacceptable.

Magnesite - ground magnesite brick is also screened out through a sieve with 4000 holes per 1 cm. A smaller fraction (10,000 holes per 1 cm) can also be consumed.

Alumina is used without grinding, only larger coarse pieces are screened out.

The mass is thoroughly mixed dry, then kneaded with water; Soluble glass (technical liquid "trisilicate) was added as a binder in the amount of 35% of the amount of water. It can also be used as a binder, its dextrin, molasses, sugar. The liquid is added in such a way that the resulting mass is sufficiently plastic.

The mass is laid on the pipe as follows: a damp rope is spread on a flat board, then two wooden planks are laid with a length corresponding to the length of the tube.

and the thickness corresponding to the thickness of the coating is at such a distance that the whole pipe is covered with mass. Between the planks, the mass produced is stretched by an even layer (at the rate of 1 m of the pipe - 3-3.5 kg of mass), a pipe, pre-lubricated with a binder, is applied, and the weight is screwed onto it along with rubbing.

The ends of the pipe are tied, and the pipe is put to dry at room temperature in a dry place.

After the mass is strong, remove the strain and continue to dry at a higher temperature (from 20 to 100 °). The small cracks formed by the drying agent are smeared with a mass of the same composition 5 to 6 days after the manufacture of the tube.

Purging with such a tube requires immersing it in the metal to the smallest possible depth (3-4 cm). The oxygen jet should travel as fast as possible.

The subject matter of the invention.

A tube for introducing oxygen into a liquid metal, characterized in that a mass consisting of a mixture of magnesite, alumina and coal is used for its outer refractory coating.