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Main Applications and Price Trends of Ferrosilicon

Ferrosilicon Definition

Ferrosilicon is mainly used as a deoxidizer and alloy additive in steelmaking. It is also used in casting, mineral processing, welding rods, light metal industry, and as a reducing agent in the smelting of certain metals. The main raw material for smelting ferrosilicon is silica ore (quartz, silica). SiO2 in the ore is generally required to be higher than 96%, and when smelting high-silicon ferrosilicon, it is higher than 98%. P2O5 in the ore should generally not exceed 0.02%. Al2O3 should not exceed 1.5%. Commonly used varieties of ferrosilicon contain 45%, 75%, and 90% silicon.

ferrosilicon-for-steelmaking

Smelting of Ferrosilicon

Low silicon ferrosilicon (containing 10-15% silicon) can be smelted in a blast furnace with iron ore and silica. Requires higher focal ratio and air temperature. During operation, the furnace’s top temperature was high and the gas contained a lot of dust, making it difficult to operate at high production rates. In the 1970s, almost all production was switched to electric furnaces.

High-silicon ferrosilicon is smelted in a reduction electric furnace with a carbon lining, using silica, steel scraps (or iron scale), and coke as raw materials. Ferrosilicon in electric furnaces is smelted by a slag-free method. The raw materials must be clean and must not be mixed with mud, sand, and other impurities. Adding wood chips and coal to the charge can improve the performance of the charge. During the smelting process, the surface of the material is easy to crust and “fire” (the surface of the material spits out fire), so the furnace must be “pounded” frequently. The furnace produces ferrosilicon every 2 to 4 hours, and the ingot is cast into an ingot with a thickness of less than 100 mm in an ingot mold. Ferrosilicon is generally made using an open-top electric furnace.

In recent years, to prevent environmental pollution, “low hood” or “semi-enclosed” electric furnaces are often used to facilitate heat recovery, smoke, and dust elimination; in the production of high-silicon ferrosilicon (containing more than 75% silicon), rotary electric furnaces are mostly used to reduce Pound the stove.

The capacity of large-scale ferrosilicon electric furnaces is 10,000 to 96,000 kVA. The power consumption for ferrosilicon production is approximately: 45% ferrosilicon, 5,000 kilowatt hours/ton; 75% ferrosilicon, 9,000-kilowatt hours/ton; 90% ferrosilicon, 14,000 kW·h/ton. To meet the requirement that the aluminum content of ferrosilicon in electrical steel should not be too high, refining methods such as oxygen blowing or chlorine blowing have been developed in recent years.

Ferrosilicon

Storage and Transportation of Ferrosilicon

Ferrosilicon is prone to powdering under certain conditions during storage and transportation. This is caused by the volume expansion caused by the phase change of FeSi and FeSi2, which contain about 34% silicon and 50 to 60% silicon. Phosphorus, sulfur, calcium, and aluminum in impurities and a humid atmosphere will cause ferrosilicon to pulverize. Ferrosilicon ingots can also easily pulverize due to segregation when they are slowly cooled. When ferrosilicon is pulverized, gases such as hydrogen, phosphine, and arsine are released, which can cause explosions. The latter two gases are toxic, so the storage and transportation of ferrosilicon must be well-ventilated to prevent moisture.

Application of Ferrosilicon

Ferrosilicon is widely used in the steel industry, foundry industry, and other industrial production. Ferrosilicon is an essential deoxidizer in the steelmaking industry. In steelmaking, ferrosilicon is used for precipitation deoxidation and diffusion deoxidation. Brickiron is also used as an alloying agent in steelmaking. Adding a certain amount of silicon to steel can significantly improve the strength, hardness, and elasticity of the steel, increase the magnetic permeability of the steel, and reduce the hysteresis loss of transformer steel. Low-aluminum ferrosilicon is a special-purpose ferrosilicon variety that has emerged in recent years. Its smelting process is complex and the product has high added value. It is an area that various ferrosilicon manufacturers are actively exploring. Examples of ferrosilicon applications are as follows:

• Add ferrosilicon powder to reduce the ferrochrome alloy powder rate. The method includes the following steps: select ferrosilicon powder with a particle size of 5 to 10 mm produced during the crushing process of ferrosilicon alloy as raw material; add silicon to the ladle during the ferrochrome alloy discharge process The amount of iron powder and ferrosilicon powder added is 0.5~1.0kg/t. When adding, add 1/3 of the total amount of ferrosilicon powder when the ferrochrome alloy comes out of the furnace to 1/4, and add ferrosilicon powder when the ferrochromium alloy comes out of the furnace to 1/2. 1/3 of the total amount, and then add 1/3 of the total amount of ferrosilicon powder when the ferrochrome alloy is 3/4 out of the furnace. On the one hand, the invention can prevent the generation of bubbles, thereby obtaining dense iron ingots, effectively reducing the ferrochrome alloy powder rate, improving the production technical and economic indicators of ferroalloy enterprises, and greatly reducing the production cost of ferrochrome alloys. On the other hand, ferrosilicon powder is produced during the crushing process of ferrosilicon alloy, which realizes resource recycling and meets the requirements of energy conservation and environmental protection. It will not cause environmental pollution and energy waste, and the method is easy to implement, simple, and convenient.

• Prepare a ferrosilicon ball, which is made from ferrosilicon raw materials and a binder. The ferrosilicon raw materials are ferrosilicon powder or a mixture of ferrosilicon powder and metal silicon powder; the silicon content in the ferrosilicon powder is 72- 75%, the silicon content in metal silicon powder is 72-85%; the adhesive is made of water, quartz sand, alkali, fluorite, Yuanming powder, and microsilica powder, and its modulus is 3-3.7. The diameter of ferrosilicon powder balls is 10-80mm. This product is made of ferrosilicon raw material, mixed with a binder specially used to make this product, and then made by a pelletizing machine. There is no need to re-smelt them, and the composition of each substance will not change during the manufacturing process. Therefore, It is easy to control the silicon content of the product; the ferrosilicon powder and metallic silicon powder used in manufacturing can be the remaining powder after crushing the exported products, thus saving my country’s existing resources and being very convenient to use.

Ferrosilicon Price Trend

Ferrosilicon has been operating weakly this week, with futures hitting new lows and spot prices loosening slightly. The raw material blue carbon fell slightly, the ferrosilicon supply remained high, some factory inventories accumulated, and the market lacked positive support. The futures market fluctuated downwards and hit a new low. The spot sentiment was sluggish. The downstream market was waiting to see the market, and factory quotations were slightly loosened. In December, steel recruitment was gradually advanced and pricing was slow. In the latter part of the week, the market price was 72#6500-6700, and 75#7000-7100 yuan/ton of cash natural blocks left the factory, down 50 yuan/ton from last week.

The export market has not improved this week. The domestic market price has loosened slightly, but the exchange rate has fallen. The export quotation has not changed much. It is temporarily stable at FOB72#1230-1270 and 75#1310-1350 US dollars/ton.

Blue coal prices fell slightly, and ferrosilicon costs loosened slightly. Ferrosilicon production began to increase in July and continued to increase for 5 months. The output in November was 492,800 tons, and the supply remained high. Affected by the production cuts of steel mills in the fourth quarter, demand fell slightly. The contradiction between supply and demand has not yet been resolved, and the market lacks confidence. The December steel bidding has entered the market, and the price of this round of steel bidding will continue to fall.

ferrosilicon-for-steelmaking

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