Steel Man: Advanced steelmaking process (CHAPTER THREE)

Recycling technology innovation

1. Hot desulphurization slag recycling process

The hot cycle method of desulfurization slag is a method of direct reuse of the steel slag (desulfurization slag) after desulphurization and refining at high temperature during the pretreatment of the next hot metal. The desulphurization slag after treatment is in the state of condensed particles, but the temperature drops afterwards, causing the condensed particles to collapse and form a new unreacted surface. Repeated use of desulphurization slag,

The desulphurization ability of the slag can be maximized by using the unreacted surface effectively. At the same time, due to the reuse of the slag in the high temperature state, the heat released during the slag discharge can be recovered, which is conducive to saving resources and reducing the environmental load.

2. Process for the return and utilization of liquid decarbonized slag

Process flow of hot slag return to dephosphorization furnace of converter: After adding scrap steel to the dephosphorization furnace and adding hot metal, the dephosphorization blowing process begins. After the end of the blowing process, the dephosphorization slag with higher P2O5 mass fraction (ω(P2O5)=6%-8%) is dumped, and the half steel (ω[P]semi≈0.03%) is poured into the half ladle, and the half steel is added into the decarburization furnace by blowing oxygen and decarburization smelting. After the end of the decarburization furnace smelting, the liquid steel from the steel to the ladle into refining and smelting, P2O5 mass fraction of low decarburization slag (ω(P2O5)≈1.5%) into the slag tank, liquid slag through the slag tank into the dephosphorization furnace, began to splash slag operation, liquid slag splash dry, began to add scrap steel and hot metal, into the next converter double operation.

3. Ladle casting slag, liquid steel return utilization process

After the hot metal is blown in the dephosphorization furnace, the half steel is poured into the half ladle, and the RH/LF/CAS ladle is poured from the ladle to the half ladle, each half ladle receives 3-4 furnace castings, and then the castings and refining slag are poured into the decarburization furnace through the half ladle.

Hot refining slag and cast residue return after the industrial production of semi-ladle is put into operation, the cast residue of ladle can be safely recycled in liquid form. Ladle molten steel is directly poured into the semi-ladle to solve the problem of heavy scrap steel; Retaining steel in ladle can improve the quality of high-grade steel. Steel slag with high alkalinity can be recycled; The cast surplus can be returned to the converter at high temperature to achieve the purpose of energy saving.