In view of the high silicon and phosphorus content of hot metal in a steel works

a converter slag-retaining double-slag smelting process is used to obtain a stable dephosphorization rate of hot metal. The specific process is to add slag-forming materials such as lime and sludge balls after the start of the blowing process for 3 min. The oxygen supply intensity is 2. 5 m

3

(t ·min) at 0 ~ 3 min

and 3. 2 m

3

/( t ·min) at 3 ~ 4. 5 min. The temperature is controlled at about 1320 °C. After the converter has first deslagging

it starts to blow and adds the late slag forming material. When the carbon monoxide in the furnace rises to a stable level

the oxygen lance position is raised appropriately to improve slaggin

g and control the end-point carbon. The test results show that the average dephosphorization rate of hot metal in the dephosphorization period is 58.09%

and the average dephosphorization rate of molten steel in the decarburization period is 85. 56% ； When the temperature of the semi-steel is 1320 °C

the basicity of the slag is 2.0

and the TFe content in the slag is 18%

a better dephosphorization effect can be obtained in the dephosphorization period. When the molten steel temperature of the converter liquid after first deslagging is 1580 °C

the basicity of the final slag is 3. 5

and the TFe content in the final slag is 20%

a better dephosphorization effect can be obtained in the decarburization period. [P

]

e

/[P

]

r

ratio at the end of the converter is 0. 90. The petrographic composition of the slag during dephosphorization and decarburization poriod from the experiment is suitable for dephosphorization of hot metal.