In solid cast iron, silicon nuggets are almost completely dissolved in austenite and ferrite, with no carbides. Silicon atoms and iron atoms can be combined with strong covalent bonds to form silicon-containing ferrite, which not only promotes the formation of ferrite, but also strengthens ferrite.
The best plan for raw material ingredients for ferrosilicon production: 1. Iron ore: Iron ore is the main raw material of ferrosilicon, generally black magnetic ore. In my country, iron reduction furnace and electric furnace are the main ironmaking methods, which require high-purity iron ore to produce ferrosilicon. 2. Silicon: Silicon is one of the main raw materials of ferrosilicon. Silicon is mainly derived from silicon ferrosilicon ore, and can also be extracted from silica sand, silica fume, and silica stone. Among them, silicon ferrosilicon ore has the highest silicon content, generally 20%~50 %. 3. Lime: Lime is a flux for ferrosilicon. Generally, high-purity lime powder is used as raw material, and the general addition amount is 5%-10%. 4. Coke: Coke is another important raw material of ferrosilicon, generally coke with low ash content, and the addition amount is 5%-10%. 5. Other impurities: Ferrosilicon generally contains other impurities, such as sulfur, phosphorus, etc. Generally, low-sulfur and low-phosphorus raw materials are used to ensure the quality of ferrosilicon.
When ferrosilicon ingredients, attention should be paid to the following:
1. The silicon block manufacturer weighs accurately, and various materials need to be weighed according to the specified amount, with small error. If weighing is not allowed, the furnace condition is not easy to grasp, and waste products may even be produced. Therefore, the batching work should be done carefully, and the accuracy of the weighing tools should be checked frequently. If a problem is found, it should be adjusted or repaired in time.
2. Silicon block manufacturers follow the prescribed order of ingredients to make the ingredients mix evenly, and the bulk density of raw materials varies greatly. In order to evenly mix the charge, the order of ingredients is coke, silica, and then steel shavings. With this batching method, the charge can be evenly mixed after falling from the feeding pipe. Whether the charge is mixed evenly or not has a great influence on smelting. In order to mix the ingredients evenly, only one batch of materials is allowed to be metered at a time, and each hopper can accommodate more than two batches of materials.
In addition, it needs to be reminded that the smaller the batch, the better it is to mix evenly, otherwise it will be difficult to mix evenly. Therefore, small batches should be used whenever possible.