Introduction of refining slag

Source: | Author:Changxing | Published time: 2085 days ago | 1247 Views | Share:

Synthetic slag refining desulphurization technology is one of the key technologies of producing clean steel of ultra low sulfur. According to the research and testing reports, we get varieties of chemical composition ratio of refining slags as below:

Chemical composition	Ratio
CaO-SiO₂-Al₂O₃-MgO-CaF₂-Na₂O	56.1 : 15.5 : 15.4 : 8.8 : 2 : 2.2
CaO-SiO₂-Al₂O₃-MgO-CaF₂	53 : 17 : 10 : 10 : 10
	59 : 15 : 8.5 : 10 : 7.5
	54.2 : 12.3 : 22 : 87 : 28
	50.41 : 0.59 : 30 : 10 : 9
CaO-SiO₂-Al₂O₃-MgO	53 : 4 : 35 : 8
CaO-SiO₂-Al₂O₃-CaF₂	32.5 : 5 : 57.5 : 5
CaO-MgO-Al₂O₃-SiO₂	50 : 15 : 20 : 15
CaO-SiO₂-Al₂O₃	65 : 10 : 25

It is the same that most basic slag use low-melting-point position ternary slag system of CaO-SiO2-Al2O3. The most important role of basic slag is to control slag basicity, which has a great influence on the desulfurization effect during refining process.

The difference of above refining slags is for fine adjustment of basic slag. According to the using effect of different chemical composition, choose different kinds and content additives, to get the expected result. The effects of different chemical compositions in refining slag are as below:

Composition	Effect
CaF₂	Reduce slag melting point and Improve its liquidity
CaO	Adjusting slag basicity and as desulfurizer
SiO₂	Adjust slag basicity and viscosity
Al₂O₃	Adjust CaO-SiO2-Al2O3ternary slag system to low melting point position
CaCO₃	As desulfurizer and foaming agent
MgCO₃(MgO)	As foaming agent,decomposition to produce magnesium oxide, which will protect ladle lining
BaCO₃(BaO)	As foaming agent, desulfurizer and inhibition of liquid steel to phosphorus
Na₂CO₃(Na₂O)	As foaming agent, desulfurizer and fluxing agent
K₂CO₃(K₂O)	As foaming agent, desulfurizer and fluxing agent
Li₂CO₃(Li₂O)	As foaming agent, desulfurizer and fluxing agent
Al	Strong desoxidant, also priority react with CaO for desulfuration, improving desulfurization result.
Si-Fe	As desoxidant,purifying molten steel