The pre-melting process of

12CaO·7Al

2

O

3

and the desulphurizing ability of

12CaO·7Al

2

O

3

based refining slag containing 10%-20%BaO

2%-6% MgO

1%-3%

Li

2

O

and

(12CaO·7Al

2

O

3

)/SiO

2

=8～10

on low carbon steel liquid (% ：0.23C

1.29Mn

0. 44Si

0. 026P

0.023S

0.04Mo

0.02Cr

0.06Cu) have been tested and studied by a

MoSi

2

shaft type electric resistance furnace in laboratory. Results show that the

12CaO·7Al

2

O

3

based pre-melting refining slag has better desulphurizing ability

with adding 3% slag at 1590 °C

the sulphur content in liquid can decrease to 0.006% from 0.030%

i. e. the ratio of desulphurization is 80.00% . With optimization of slag ingredient by using orthogonal method

it is obtained that the optimizing slag series of

12CaO·7Al

2

O

3

based refining slag is 15% BaO

4% MgO

3%Li

2

O and

(12CaO·7Al

2

O

3

)/SiO

2

=9

.