A method of casting a steel semi-product wherein a liquid steel is poured from a ladle to a tundish through a shroud including the steps of determining the light intensity emitted from the surface of the liquid steel in the tundish, detecting, based on said determined intensity, the presence of an open-eye at the surface of the liquid steel and emitting an alert towards an operator when an open-eye is detected.

Provided are a method and a system for a slag thickness detection and a slag-adding prediction. The method includes: acquiring real-time measurement data and real-time auxiliary data of a slag point on a surface of a protective slag layer of a casting mold; calculating a real-time slag thickness value corresponding to the slag point by using the real-time measurement data and the real-time auxiliary data of the slag point; and predicting a location on the surface of the protective slag layer where a slag-adding is to be performed and a slag-adding time when the slag-adding is to be performed based on a change in the real-time slag thickness value corresponding to the slag point by taking a preset slag thickness value as a reference.

Slide closure unit on the spout of a metallurgical vessel, preferably a copper-anode furnace, includes a housing in which refractory closure plates, as well as at least one connecting refractory inner casing, are arranged. A removable induction heater is provided, having at least one induction coil surrounding the refractory inner casing outside of the housing. In this way, it is possible to constantly keep the melt located in the outlet channel of the spout sufficiently warm so that it does not freeze before and/or during the pouring of the melt, or that any frozen metal and/or slag can be melted in the spout.