Auxiliary slag melting agent for tundish and application method thereof

The invention discloses an auxiliary slag melting agent for a tundish and an application method thereof. The application method is characterized in that the temperature of a first furnace is 1600 to 1610 DEG C after the refining is finished, and the first furnace is killed for not less than 25min; the temperature of continuous casting furnaces is 1590 to 1600 DEG C, and the continuous casting furnaces are killed for not less than 20min; after a steel ladle is started to be casted and before a lower edge of a long sprue is covered with the liquid in the tundish, 150-200kg tundish covering agents are introduced from the lower part of the long sprue of a big tundish, two sides of a stopper rod are roasted and then 50-100kg tundish covering agents are idly introduced to the two sides of the stopper rod, and 300-500kg tundish covering agents are introduced once after the long sprue is full of the liquid; the degree of superheat of the tundish is no lower than 25 and no greater than 40 DEG C; since the casting of a third furnace, 10-30kg auxiliary slag melting agents for tundish are introduced near the stopper bar when the liquid in the tundish is filled to reach the normal level. With the adoption of the application method, the technical problem that a high-alkalinity tundish covering agent is used in the prior art and easily leads to the reduction of control precision of a crystallizer can be solved, and thus the purity and the surface quality of steel and iron products can be improved.