Drainage sand particles have high bulk density, high melting point, and good chemical stability at high temperature

The sliding nozzle drainage sand is an unshaped refractory material filled in the upper nozzle of the sliding nozzle and the steel hole of the upper sliding plate. When re-casting, it can make the molten steel in the ladle flow down.

With the development of the refining technology outside the furnace, the drainage sand works under more severe conditions, which mainly refers to the increase of the temperature of the molten steel and the extension of the residence time of the molten steel in the ladle. Excessive sintering under high temperature and high pressure, or molten steel seeping into the drainage sand, due to the temperature drop, the molten steel condenses, when the lower slide is in the open position, the drainage sand does not come down, that is, it cannot be poured naturally. Every time this kind of situation is encountered, the operator has to blow off the nozzle with an oxygen blowing tube to help start pouring. Drainage sand manufacturers have many disadvantages in this way, such as threatening the personal safety of workers, expensive oxygen blowing pipes, increased consumption, high oxygen blowing temperature and damage to sliding nozzles. After the molten steel is oxidized, it will cause casting metal non-metallic inclusions , In particular, in order to prevent the molten steel from oxidizing and adopting protective castables (installing long nozzles), the sliding nozzles are required to be automatically poured.

According to the working conditions of the drainage nozzle and the analysis of the reasons for the decrease of the pouring rate, in order to improve the automatic pouring, we all propose the following performance requirements for the drainage sand:

(1) Drainage sand particles have large volume density and high melting point; moderate sintering between particles at high temperature, but the sintering layer should be thin. Large volume density and moderate sintering will prevent the drift sand from being scattered and floated by molten steel.

Drainage sand manufacturers

(2) Drainage sand has good high-temperature chemical stability, does not react with the material of the nozzle, and has good corrosion resistance and non-wetting properties to molten steel and molten slag.

(3) The particle size is moderate. If the particle size is too coarse, the molten steel will easily infiltrate along the gap between the particles; if the particle size is too fine, the drainage sand is easy to sinter into a whole.

(4) The natural accumulation angle of the drainage sand is as small as possible. The surface of the particles should be as smooth as possible, and the fluidity should be good, so that it will not arch in the nozzle.

(5) The water content of the drainage sand is low, <0.5%.

The particle composition, particle shape, material, method of use and structure of the water outlet of the ladle sliding nozzle drainage sand are directly related to the level of automatic pouring rate, which is also related to the personal safety, labor intensity and production efficiency of workers And steel quality. Therefore, with the development of refining technology outside the furnace, it is necessary to continuously study on it and always maintain a high automatic pouring rate. The sliding nozzle drainage sand is an unshaped refractory material filled in the upper nozzle of the sliding nozzle and the steel hole of the upper sliding plate. When re-casting, it can make the molten steel in the ladle flow down.