After applying the slag splashing protection technology, the bottom of the converter is easy to rise. The main reason is that the final slag used for splashing slag has high basicity, the (MgO) content reaches or exceeds the saturation value, the furnace temperature decreases after the furnace is turned down, and MgO crystallizes and precipitates. There is an increase; part of the molten slag adheres to the surface of the furnace lining when the slag is splashed, and the remaining part is concentrated on the furnace bottom, which combines with the periclase crystals of magnesia-carbon bricks at the bottom of the furnace, causing the bottom of the furnace to rise. When the slag is splashed in the re-blowing process, the bottom is still supplied with air, and cold air is blown in from the top and bottom, the furnace temperature is lowered again, and the molten slag is further viscous; the high melting point crystals C2S and C3S grow and grow, and surround the MgO crystal or Solid particles that form a hard dense layer. Improper gas supply at the bottom will aggravate the height of the furnace bottom.
To prevent the bottom of the furnace from rising, the following measures should be taken:
(1) The composition and temperature of the slag at the end point should be controlled to prevent the slag from being too sticky;
(2) Use a lower suitable slag splash gun to splash slag;
(3) Sufficient nitrogen pressure and flow;
(4) After slag splashing, pour out the remaining slag in time;
(5) Reasonable slag splashing frequency;
(6) When it is found that the furnace bottom rises beyond the specified limit, blow oxygen through an oxygen lance to melt, or add an appropriate amount of Fe-Si to melt the rising furnace bottom.