Aluminum slag balls have the effect of deoxidation and synthetic refining agents. Its chemical composition is Al ≥ 40%, Al2O3: 10-20%, MgO ≤ 3.0%, CaO: 10-15%, SiO2 ≤ 6.0%, S ≤ 0.50%, P ≤ 0.50%; Particle size: 10-50mm. When the steel is first refined, it can be used as a deoxidizer to remove the free oxygen in the steel. In addition, it can quickly cover the air in the liquid level.
There are two forms of aluminum slag balls to be added: one is that the electric furnace is used as a deoxidizer in the tapping process together with other deoxidizers to reduce the dissolved oxygen in the steel to the control range; the second is when the molten steel reaches the LF ladle refining position. In order to adjust the components of the slag, the oxygen in the slag is quickly removed to form a suitable refining slag system.
Application in actual production:
1 electric furnace process to join. The final deoxidizer for the furnace uses aluminum slag balls and silicon-calcium barium. The amount of deoxidizer added based on the carbon content of the end point is 0.5-1.0 kg/t for aluminum slag balls, and 2.0-3.0 kg/t for silicon-calcium-barium. Adding sequence: The molten steel is discharged to 20t and silicon-silica-barium and aluminum-slag balls are added into the ladle. The tapping time is more than 110 seconds, and the slag is forbidden in tapping.
2LF refining process. During refining, the composition and slagging are adjusted according to the composition of the molten steel. The addition of the slagging agent is: aluminum slag balls, 50-100 kg; carbide powder, ferrosilicon powder is 20-30 kg, and fire brick sand is 15-25 kg.
3 desulfurization situation. The use of aluminum slag ball slagging speed, high desulfurization efficiency, slag-like refining can be white within 15 minutes, very favorable for desulfurization and de-inclusion.
4 product inclusions and oxygen and nitrogen content. The use of aluminum dross deoxidation and refining slag has been successful production of wire rod wire rod, wire rod specification is φ5.5mm, wire rod purity is very low inclusion content: Class A 0-0.5/0.5; B, Class C 0.5- 1/0.7; Class D 0-1.5/1. [O] is 25-60/39×10-6, [N] is 45-80/68×10-6, and the quality is very good.
The aluminum slag balls applied on the above LF smelting furnace have been applied in Xinjiang Bayi Iron & Steel Co., Ltd. in China, with good results, and are expected to be extended to other special steel smelting applications.