With using Factsage thermodynamic calculation and test in laboratory

the effect of basicity (R)2.5 -5.4

Al

2

O

3

(14%-30% ) and MgO (3%-15% ) content on mineralogical phases precipitation in CaO-Al

2

O

3

-SiO

2

-MgO quaternary refining slag for bearing steel GCr15 has been studied. Results show that at 1 600 °C

with basicity of slag increasing from 2.4 to 5.4

the amount of precipitation of silicate mineral in slag decreases from 56% to 30%

the total precipitation amount of three kinds of minerals of Ca

3

Al

2

O

6

、Ca

3

MgAl

4

O

10

and

CaAl

2

O

3

increases from 28. 0% to 58. 2% ； with increasing Al

2

O

3

content in slag from 14% to 30% (R4. 4

7% MgO)

the precipitated metal oxide solid solution amount decreases from 26% to 3. 5%

silicate minerals decrease form 42% to 33%

while the precipitated amount of three kinds of minerals of Ca

3

Al

2

O

6

、Ca

3

MgAl

4

O

10

and CaAl

2

O

3

increases from 32. 2% to 63.2% ； and with increasing MgO content in slag from 5% to 15% (R4.4

26% Al

2

O

3

)

the change of precipitated amount of silicate minerals

Ca

3

Al

2

O

6

、Ca

3

MgAl

4

O

10

and CaAl

2

O

4

is not obvious. With basicity of slag 4-5

4. 5%-5. 5% MgO and 24%-27% Al

2

O

3

the quaternary slag has suitable viscosity and melting temperature

and has better fluidity and ability to absorb inclusions in liquid. The thermodynamic simulation results are consistent with the results of mineralogical phases ingredient defined by hot status remelting experiment.