What refractory materials are used in the lead smelting industry? What are the performance requirements?

The middle and upper non working layers and flue of the blast furnace body are constructed with red bricks. The upper working layer of the furnace body is built with clay bricks. The middle working layer of the furnace body is generally built with magnesium bricks, magnesium chromium bricks, or chromium bricks; The operating temperature of the lower part of the furnace body and the tuyere area is about 1300 ℃, with some parts reaching up to 1500 ℃. At the same time, it is subjected to chemical erosion from lead liquid and slag, and the operating conditions are relatively harsh. The working layer of this area is generally made of dense clay bricks, high alumina bricks, or magnesium chromium bricks, and water-cooled plates are installed for protection. When using dense high alumina refractory castable, anchor nails must be welded on the water-cooled plate first, and then the working layer must be poured, with a thickness of approximately 230mm.

Under the condition of using oxygen rich blast, the lining around the tuyere area of the furnace can be used for more than 300 days; The non working layer of the furnace is built with clay bricks, while the working layer is built with alkaline bricks such as fired magnesia bricks, magnesia chromium bricks, or chromium bricks. Magnesium or magnesia chromium refractory ramming materials can also be used for ramming. Under normal operating conditions, the usage cycle of this area is 3-5 years. Due to the high density and strong permeability of lead liquid, it is easy for the bottom bricks of the furnace to float and cause expansion and deformation of the masonry. The furnace hearth needs to be repaired once a year. When using phosphate high alumina refractory ramming material with a 70% AL2O3 content to ramme the furnace hearth, due to its good overall integrity, no gaps, and difficulty in penetrating lead liquid, the surface remains smooth and even after one year of use. Only the lining near the siphon mouth has a slight bulging phenomenon, and it can still be used after minor repairs, which can basically synchronize with the entire life of the furnace lining; The lining of the front bed and flow channel of the blast furnace is generally built with high alumina bricks or magnesium bricks, with a service life of about 3 years.

This furnace is a new type of furnace that combines lead and zinc smelting furnaces to treat lead zinc oxide ore or lead zinc mixed sulfide ore. It is a thermal equipment that can directly smelt and produce lead and zinc. The lead zinc closed blast furnace mainly consists of a closed blast furnace, a condenser, a lead mist chamber, and a flue, and is connected to the lead zinc distillation and refining device.

The cross-section of the furnace is rectangular, and the walls at both ends are in a circular arc shape. The standard furnace has 36 air vents, with an area of approximately 10m2. The working layer of the furnace hearth lining and the lining layer of the water-cooled plate on the furnace waist are generally constructed with magnesium chromium bricks. The lining of the non working layer of the furnace and the lining of the furnace body are constructed with clay bricks and dense clay bricks. The top of the furnace and the inclined lining at the connection with the lead mist chamber are generally poured with high alumina cement refractory castable on site, and can also be made into prefabricated blocks for hoisting and masonry. The bottom and top of the lead mist chamber are built with dense clay bricks, or poured with high-strength refractory castables. The side walls are subjected to the erosion and chemical erosion of lead mist, which causes rapid damage. Therefore, clay combined with silicon carbide bricks is required for construction. The rotor and shaft inside the lead mist chamber are made of graphite or silicon carbide materials. The chimney and other parts are built with ordinary clay bricks. The service life of a furnace is generally 3-4 years, and the lining of its loading port, furnace waist, tuyere area, and slag line area is more prone to damage. Minor repairs are required in each furnace service. The lifespan of parts such as the lead mist chamber and flue is equivalent to several furnace services, but the rotor and shaft need to be replaced multiple times. The bottom and top of the lead zinc separation chamber are generally constructed with clay bricks or dense clay bricks, while the side walls are constructed with clay bricks for non working layers and magnesium chromium bricks for working layers. The bottom of the lead liquid flow tank and the lead discharge tank are made of AlzO. High alumina bricks with a content of 65% are used for masonry, while the groove walls are constructed with magnesium chromium bricks or chromium bricks. The flow channel can also be poured with refractory castable of the same material to form a strong overall lining. The groove cover plate is prefabricated with high alumina cement refractory casting material. The lining of the lead zinc separation chamber and flow channel has good service conditions, less damage, and can work for several furnace services. The lining of the combustion chamber, heat exchanger chamber, and chimney of lead and cadmium towers is generally built with clay bricks, and several furnace sections can also be used.

Refractory materials for oxygen bottom blowing lead furnace. This furnace is a thermal equipment for directly refining lead from lead concentrate. The furnace is in a long cylindrical shape, horizontally placed on two support rings, and can rotate 90 degrees. The length of the furnace is about 22m, divided into a reduction zone and an oxidation zone. There is a partition wall with a height of 700mm and a thickness of 500mm between the two zones, and holes are left at the bottom to connect the two zones. There are smoke exhaust outlets and siphon lead discharge outlets installed in the oxidation zone, and 6 oxygen nozzles are also installed. There is a loading port above the nozzles. There are 8 sleeve type nozzles installed in the reduction zone, with coal powder and oxygen or natural gas and oxygen sprayed into the nozzle holes, and nitrogen protection is provided between the gaps. The melting pool, slag line area, partition wall, loading port, and furnace wall opposite the nozzle of the QSL lead smelting furnace are generally built with cast magnesium chromium bricks, while the lining of other parts is built with directly bonded magnesium chromium bricks or fired magnesium chromium bricks. Its working layer thickness is 300mm. The lining of the flue and non working layer is generally constructed with clay bricks. Under normal operating conditions, the service life of the furnace is about 1 year, and the service life of the bottom nozzle is generally 1-2 months.

The refractory material used in the Kiefset direct lead smelting furnace is characterized by combining the roasting and smelting of lead concentrate in the same furnace. It consists of a straight cylindrical smelting tower and an electric furnace, which share the same furnace and are separated by water-cooled plate partition walls. The partition walls are inserted into the molten pool at a depth of 200-400mm. On one side of the furnace top, there is a tall smelting tower (vortex furnace) standing upright, and a combustion device is installed at the bottom of the tower. The cross-sectional area of this area is about 16m2, and the operating temperature is generally above 1350 ℃; On the other side, electrodes are installed to form the electric furnace section, with a cross-sectional area of approximately 77m2. The designed smelting capacity of the furnace is generally 5.0-6.5t/m2.

The lining of the high-temperature zone of the furnace melting tower is susceptible to material erosion, chemical erosion, and high temperature, making it more susceptible to damage. The electric furnace lining is mainly subjected to high temperature and chemical erosion, and the lining body around the slag line area and electrode holes is damaged quickly. The partition wall is suspended and inserted into the molten pool, with strict usage conditions and the most vulnerable to damage. Therefore, all working layers of the furnace are constructed with magnesium chromium bricks, and vulnerable parts are also protected with water-cooled copper sleeves to improve their service life. The water-cooled partition wall is protected by magnesium chromium bricks, and anchor nails can also be welded on the board, and then magnesium refractory castable can be poured or rammed. Under normal operating conditions, the service life of the furnace is approximately one year. During this period, the lining around the top of the electric furnace, electrode holes, partition walls, and nozzles needs to undergo several minor repairs. The lining of the lead mouth and other parts also needs minor repairs.