STEEL BASIC OXYGEN FURNACE

REFRACTORIES FOR STEEL BASIC OXYGEN FURNACE

WE SUPPLY VARIOUS REFRACTORIES FOR STEEL BASIC OXYGEN FURNACE

Basic Oxygen Furnace (BOF) steelmaking operations are also sometimes referred to as Basic Oxygen Steelmaking (BOS). This is the most powerful and efficient steelmaking technology in the world. About 71% of crude steel is produced by this process. The BOF process was developed in the early 1950s at two steel plants in Linz and Donawitz, Austria, so the BOF process is also known as LD (the first letter of the two cities) steelmaking.

There are several variations on the BOF process. There are mainly top blowing, bottom blowing, and the combination of the two, which is the so-called joint blowing.

The steelmaking process is a spontaneous, or self-sufficient, energy source that uses gaseous oxygen (O2) to convert liquid iron (hot metal) into steel to oxidize unwanted impurities in the hot metal (HM). The oxygen used must be of high purity, usually a minimum of 99.5%, otherwise the steel may absorb harmful nitrogen (N2).

The main raw materials for steel plants are generally HM (about 80% or more) from the blast furnace and the remaining scrap. These are packed into BOF containers. Oxygen is blown into the BOF at supersonic speeds. It oxidizes the carbon (C) and silicon (Si) in the HM, releasing a lot of heat that melts the scrap. The oxidation of iron (Fe), manganese (Mn) and phosphorus (P) produces less energy. The flux used in this process is mainly calcined lime (more than 92% CaO). This lime is calcined from limestone low in silicon dioxide (SiO2). The combustion of carbon monoxide (CO) after leaving the converter also transfers heat back to the molten pool. The product of the steel plant is liquid steel with a specific chemical analysis at a temperature of about 1650 degrees Celsius.

The term "basic" refers to the furnace's refractory lining, made of alkaline materials (dolomite and magnesite). The refractory lining must have specific properties to withstand the corrosive effects of high temperature, highly oxidizing and basic slags, as well as wear during charging and blowing. Basic slag is required to remove P and sulfur(S) from the liquid charge.

 

Magnesia carbon brick---working layer
Magnesia brick---safety layer