I believe that anyone who has been in contact with ferrosilicon knows what ferrosilicon is, and ferrosilicon is an alloy material composed of silicon and iron. But ferrosilicon is not a ready-made combination. Ferrosilicon reduces silicon from silica containing SiO2, so the raw materials for ferrosilicon smelting mainly include silica, carbonaceous reducing agent, and steel shavings.
Production of one ton of ferrosilicon raw material and power consumption are:
·reducing agent: 890—930kg
·Steel shavings: 220—230kg
Common silicas are quartz and quartzite. Quartz is a mineral with a dense crystal structure and a density of 2650kg/m3. Pure quartz is colorless or milky white, sometimes gray and reddish due to the content of magazines, glassy, brittle, and has a melting point of 1973K. Quartz is more expensive, only for the production of crystalline silicon.
Quartzite is made of quartz particles bonded by a binder. Its main component is also sio2, which has high density and compressive strength. Yellow, rose, and other tones.
Silica for smelting ferrosilicon should meet the following requirements:
Silica should be high in silicon dioxide and low in impurities, usually SiO. >98%. The reduction of silicon dioxide with carbon requires a relatively high temperature, especially when the content of silicon dioxide is low and combined with calcium oxide to form a stable compound, the reduction temperature is higher, which will increase the power consumption of smelting and the amount of reducing agent.
【carbonaceous reducing agent】
The main requirements for the reducing agent are high fixed carbon content, low ash content, low volatile matter, large porosity, good chemical activity, high resistivity; certain mechanical strength at high temperatures; wide distribution, and low price. From the above requirements, charcoal, petroleum coke, and pitch coke are the most suitable reducing agents, but they are expensive, and they are only used when smelting alloys with high purity and difficult to reduce; bituminous coal, anthracite, and gas coal coke have high resistivity. , low ash content, but brittle after being heated, it can only be used in conjunction with other reducing agents.
The iron-containing raw material is the regulator of the ferrosilicon composition. When ferrosilicon is smelted in an electric furnace, carbon steel turnings with low phosphorus content, no alloying elements, and non-ferrous metals are generally used, and the steel turnings should not have foreign inclusions and oil stains. In addition, small scraps and rolled steel skins of other carbon steels can also be used.
During the reduction process of silicon dioxide, steel shavings can promote the reduction, absorb the reduced silicon, and destroy silicon carbide. In order to melt the steel shavings as soon as possible and give full play to their effect, it is required that the steel shavings should not be too long. In addition, the long curled steel shavings will make it difficult for automatic assembly and cannot make it evenly distributed in the furnace, so the curled length of the steel shavings should be less than 100mm.
The use of iron oxide can improve the furnace condition and make the slag flow out easily, but the reduction of iron oxide to iron needs to consume part of coke and electric energy, which increases the unit power consumption and reduces agent consumption.
Iron ore cannot be used as iron-containing raw material. Because the ore will occur a lot of slags and a lot of extra electricity will be consumed