China's steel ladle refractories with technical progress measures

Steel ladle is an important hot work equipment in iron and steel industry, from the ingot mold casting period of pure steel equipment, the development of continuous casting of steel, smelting equipment outside the furnace refining, the use of very harsh conditions, the refractory material requirements are increasingly high.

China's ladle refractories in the continuous development and progress. From clay bricks, high alumina bricks, wax stone bricks, aluminum magnesium bricks, magnesium carbon bricks, magnesium calcium bricks, aluminum magnesium carbon bricks, magnesium dolomite bricks, magnesium dolomite carbon bricks, etc., the service life of the refractory materials for ladle lining from the year when the service life of clay bricks 10 times or so, to the present service life of alkaline refractory materials are generally in the 150 ~ 200 times.

1、Castable material set casting, spraying and emission reduction, improve the life of ladle

Steel ladle using castables as a whole lining than brick lining to eliminate brick seams, construction to facilitate mechanization, construction speed, labor-saving, reduce the cost of lining, improve the service life, reduce refractory consumption.

From the early 1980s water glass combined with aluminum and magnesium castables to 95 successful research and development of the Bureau of wrong sailing earth-based spinel burning material, as well as large-scale ladle with corundum - spinel around the injection material are higher than the service life of the brick shed lining, refractory material consumption is reduced. In particular, the use of sets of pouring, that is, when the liner erosion more than half of the original thickness, remove the residue on the package liner residual steel, the first patch casting package bottom, and then sit on the tire mold patch casting package wall, patch casting after the size of the liner and the new package of the same liner, after baking can be put into use, the number of times and the use of the new package is similar. As the material used for making up the casting is only 1/3~1/2 of the amount of material used for the new lining, it saves a lot of refractory material consumption. In the case of no serious cold steel freezing accidents in the ladle, the set of pouring can be continuously recycled, which basically realizes the zero emission of residual refractory materials.

For example, Lai Steel 130t ladle using skinning set casting repair process, and with spraying and patching lining welding technology for minor repairs, after three minor repairs 4 times the age of the package up to 190 times or more, the refractory consumption of working lining compared to the set of casting process to reduce the 0.61kg/t steel. Then the working lining is peeled off and poured in the repair, and then renewed lining for 3 times of minor repair, according to this cycle of 8~9 cycles, which can make the ladle casting working lining life of more than 1500 times. If the casting material is further optimized, set casting and spraying technology is further improved, not only the ladle life is greatly improved, and basically do the residual refractory material zero discharge. China's small ladle basically use the set of pouring process, large ladle has also done the set of pouring test, the effect is very good, but not in the production of a comprehensive promotion.

Also available flame spray patching technology on the ladle lining repair, so that spray patching material and the surface of the ladle wall to achieve a high adhesion rate, spray patching material and attached between the lining wall, and soon form a high strength ceramic combined with the new lining. For example, with magnesium carbon brick or aluminum magnesium carbon brick masonry continuous casting refining ladle, the use of MgO45% ~ 55%, CaO20% ~ 30%, FeO18% ~ 24%, SiO24% ~ 8%. The introduction of FeO, SiO2 is to make the flame spray patching process to form a liquid phase, improve the adhesion rate and sintering of spray patching material. Ladle flame spray patching belongs to advanced technology, by the mechanization, automation, high degree of equipment, will be erosion, damage, wear and tear of the lining in time to repair, significantly improve the life of the ladle lining, so that the refractory lining of the best use of refractory materials, to the ladle of the permanent lining, after the use of refractory materials, zero emissions step forward.

Tian Shouxin and others have done to reduce refining ladle refractory unit consumption test 'a steel plant electric furnace 60tLF ladle slag line for the regeneration of MgO-C material 66% of the regeneration of MgO-C bricks, molten pool for the regeneration of 88% of the regeneration of MgO-C bricks. In order to reduce the erosion of the lining, the control of the end of the electric furnace sores and FeO content in the slag, the use of magnesium-calcium-carbonaceous reformation agent, improve the maintenance system, and the use of second-grade high-alumina bricks to patch the molten pool, so that the ladle life is increased from 40-50 times to 88 times, and the consumption of refractory materials is reduced from 9.3kg/t steel to 5.6kg/t steel.

Qiu Wendong of Baosteel put forward the ideal configuration of ladle refractory material as % of the package wall insulation layer is 30mm thick, the permanent layer of the overall casting thickness of 80~100mm, the working layer of the casting thickness of 180~210mm, the slag line using low carbon magnesium carbon bricks thickness of 180~230mm, the bottom of the package as a whole, according to the size of the package to choose the appropriate thickness. Referring to foreign experience, formulate repair mode (see table 1), develop successive pouring repair technology, continuous construction lining without abandoning the original lining.