Lead smelting is basically carried out by the sintering blast furnace method. The furnace types are blast furnace, lead-zinc closed blast furnace, oxygen bottom blowing lead smelting (QSL) furnace and Kifset method direct lead smelting furnace.
Refractory materials for lead-zinc closed blast furnace This furnace is a new furnace type that combines lead smelting furnace and zinc smelting furnace to process 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 airtight blast furnace is mainly composed of a airtight blast furnace, a condenser, a lead mist chamber, a flue, and other parts, and is connected to the lead-zinc retention refining device.
The standard furnace is equipped with 36 air outlets, and the area of the air outlet area is about 10m2. The working layer of the furnace hearth lining and the furnace waist water-cooling plate lining are generally made of refractory materials magnesia bricks. The non-working layer of the hearth and the lining of the furnace body are made of clay bricks and dense clay bricks. High alumina cement refractory castables are generally used for on-site pouring of the furnace roof and the chute lining at the connection with the lead mist chamber. They can also be made of prefabricated blocks and hoisted for masonry construction. The bottom and top of the lead fog chamber are built with dense clay bricks, or are poured with high-strength refractory castables. The side walls bear the erosion and chemical erosion of lead fog and are damaged quickly, so they need to be built with clay combined with silicon carbide bricks. The rotor and shaft in the lead fog chamber are made of graphite or silicon carbide materials. The flue and other parts are built with ordinary clay bricks.
The service life of a furnace is generally 3 to 4 years. The linings in the charging port, furnace waist, damper area, and slag line area are easily damaged, and require minor repairs several times during 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 many times. The bottom and top of the lead-zinc separation chamber are generally built with clay bricks or dense clay bricks, the non-working layers of the side walls are made of clay bricks, and the working layers are made of refractory materials magnesia-chromium bricks . The bottom of the lead liquid flow trough and the lead outlet trough are made of Alz0. It is built with high-alumina bricks with a content of 65%, and the tank walls are built with magnesia-chrome bricks or chrome bricks. The launder can also be poured with refractory castables of the same material to form a highly integrated trough lining. The groove cover plate is made of high alumina cement refractory castable prefabricated blocks. The linings of the lead-zinc separation chamber and launder are in good condition, less damaged, and can work for several furnaces. The linings of the combustion chambers, heat exchanger rooms and chimneys of lead towers and brocade towers are generally built with clay bricks, and several furnaces can also be used.
