Drainage sand is very commonly used in the smelting industry. Drainage sand has the advantages of good fluidity, good permeability, fast flow rate and steel erosion resistance.Drainage sand is mainly used in metallurgical industry to improve steel quality and output and reduce product cost. Drainage sand is an essential refractory for eccentric furnace tapping, which is prepared by mixing forsterite and fused magnesite as main raw materials and carbon materials as additives according to specific particle size and weight percentage; After trial use, it has been proved that the drainage sand has good dispersive fluidity, high refractoriness, no sintering, no blockage, drainage rate of tapping rate up to 100%, using temperature ≥ 1750℃, no chemical reaction with molten steel and alloy components, no variability of storage quality and can meet the requirements of steelmaking process. It is the most ideal refractory for eccentric furnace steelmaking.
In iron and steel smelting industry, ceramic foundry sand is popularized to be used as drainage sand of molten steel refining ladle, and its trial specification is 30 mesh.n drainage sand production, the advantage of ceramic foundry sand instead of chromite sand is high refractoriness; The main component of ceramic foundry sand is aluminium oxide, so the refractoriness is more than 1820 ℃; The thickness of sintered layer can be reduced by not sintering excessively at a certain molten steel temperature.Because the Baozhu sand is round and the granules in the sintered layer are in point contact, the strength of the sintered layer can be effectively reduced and the drainage sand can be used for casting. Ceramic foundry sand is spherical granular, close to true circle, smooth surface, no concave-convex veins, its liquidity is good, easy to open casting.In the drainage sand, the ceramic foundry sand can be used according to the proportion, and the chromite sand can also be replaced by part of the ceramic foundry sand, and the price is far lower than the chromite sand. Ceramic foundry sand has low thermal expansion rate, low thermal conductivity, small expansion after heating, and can prevent shed materials; Contact with the molten steel can be formed with a protective layer, using less to prevent drainage floating, molten steel penetration.Attention should be paid to prevent steel flow from impacting ladle directly during tapping, which will affect the self-flow rate during opening. The drainage agent added should be piled up into small package and the center of package should be aligned with the outlet of ladle.
At present, chromite sand and silica sand are the main varieties of ladle drainage agent. Chromite sand drainage has good performance, but it causes serious environmental pollution and high cost; Silica sand drainage agent is not conducive to the free fall of sand filling, poor natural fluidity, easy to cause shed materials.Ceramic foundry sand drainage agent is an ideal substitute for chromite sand, and its particle shape is spherical, which can effectively reduce the strength of sintering layer and is conducive to the opening of drainage sand casting; In addition, its small specific gravity is much lower than the cost of chromite ore.
