For the amorphous master alloy with melting point of 1 250 ℃

through adding B

2

O

3

to the CaO-SiO

2

-Al

2

O

3

base slag system

the low melting temperature slag system containing boron was designed. The phase diagram of CaO-SiO

2

-Al

2

O

3

-B

2

O

3

quaternary refining slag system was analyzed by Factage7.2 software simulation calculation. With the proportion of B

2

O

3

increased from 7% to 19%

the area ratio of low melting temperature in the phase diagram is increased from 5% to 46%. With controlling the content of B

2

O

3

at 13%～16%

the melting temperature is 1 100～1 200 ℃

which is suitable for the smelting of amorphous master alloy. The experimental results indicate that the melting temperature is 1 150±25 ℃

which is consistent with the simulated ones.