First, blast furnace
Blast furnace is widely used in copper, lead, lead zinc, antimony and other metals rough refining process.
A blast furnace is composed of a top, a body, a bed (also known as a throat), a hearth and a tuyere device.
Solid materials such as smelting charge (concentrate, sinter, etc.), coke, flux, reverse charge, etc. are added from the top of the furnace, and the high-pressure air pumped into the side tuyere device under the furnace body is melted, oxidized, reduced and other reactions with the downward material during the upward process to complete the smelting process, and the liquid metal, matte, and slag are discharged from the throat or furnace cylinder under the furnace. Flue gas, soot, gaseous metal or metal oxides are discharged from the flue gas outlet of the furnace top. At present, the furnace is mostly closed top, the furnace is a full water jacket, the refractory material is only used in the throat and the furnace cylinder, because the slag is basic slag, so the throat part mainly uses magnesium brick, magnesia chrome brick, aluminum chrome brick; Magnesia brick, magnesia chrome brick and aluminum-chrome brick for the side wall of the hearth and the upper part of the hearth bottom; The bottom of the furnace is arched.
Second, the reverberatory furnace
The operating temperature of the furnace head is generally 1400 ~ 1500 ° C, and the temperature of the flue gas is generally 1150 ~ 1200 ° C. The bottom of the furnace is successively composed of asbestos sheet, insulation brick layer, clay brick layer, magnesia-aluminum brick or magnesia-brick layer from bottom to top. The furnace wall is mostly made of magnesia-aluminum bricks or magnesia-aluminum bricks, some important parts are made of magnesia-chromium bricks in order to extend the service life, and the external wall is generally made of clay bricks. The top of the furnace adopts hanging type roof, and the top of the small reverberatory furnace adopts brick arch, and the arch material is magnesium-aluminum brick.
Most of China's lead (copper) smelting factories use the traditional sintering - blast furnace melting process, because it has the following defects:
A. The sulfur combustion in the sintering process is not sufficient, and the ratio of return material is high;
B. Low lead (copper) content in blast furnace charge;
c, a large number of smoke pollution of the environment.
Therefore, people have been trying to explore the new process of lead smelting, its purpose is no more than two aspects:
1, the use of reaction heat for smelting;
2. Replace the original multi-step method with a one-step process.
Foreign countries have successfully developed Isa furnace (Osmet furnace), Kaldo furnace, QSL process, Kifset process, Silo process, oxygen enriched lead furnace and other new types of lead smelting furnace and new processes.