What is Calcium Silicon?
Calcium silicon, also known as ferro silicon calcium, is a binary alloy composed of silicon and calcium and belongs to the category of ferroalloys. Its main components are silicon and calcium, and it also contains impurities such as iron, aluminum, carbon, sulfur, and phosphorus in varying amounts. In the iron and steel industry, it is used as a calcium additive, deoxidizer, desulfurizer, and denaturant for non-metallic inclusions. It is used as an inoculant in the cast iron industry.
Other impurities are specified according to different purposes. In addition, on the basis of silicon-calcium alloys, other elements are added to form ternary or multi-element composite alloys. Such as Si-Ca-Al; Si-Ca-Mn; Si-Ca-Ba, etc., used as deoxidizer, desulfurizer, denitrification agents, and alloying agent in iron and steel metallurgy.
The Specification of Calcium Silicon
Since calcium has a strong affinity with oxygen, sulfur, hydrogen, nitrogen, and carbon in molten steel, silicon-calcium alloys are mainly used for deoxidation, degassing, and fixation of sulfur in molten steel. Calcium silicon produces a strong exothermic effect when added to molten steel. Calcium turns into calcium vapor in molten steel, which has a stirring effect on molten steel and is beneficial to the floating of non-metallic inclusions. After the silicon-calcium alloy is deoxidized, non-metallic inclusions with larger particles and easy to float are produced, and the shape and properties of non-metallic inclusions are also changed. Therefore, silicon-calcium alloy is used to produce clean steel, high-quality steel with low oxygen and sulfur content, and special performance steel with extremely low oxygen and sulfur content.
The addition of silicon-calcium alloy can eliminate the nodulation of the steel with aluminum as the final deoxidizer at the ladle nozzle, and the clogging of the nozzle of the tundish of continuous casting | ironmaking. In the external refining technology of steel, silicon-calcium powder or core wire is used for deoxidation and desulfurization to reduce the content of oxygen and sulfur in steel to a very low level; it can also control the form of sulfide in steel and improve the utilization rate of calcium.
In the production of cast iron, in addition to deoxidation and purification, silicon-calcium alloy also plays an inoculating role, which helps to form fine-grained or spherical graphite; makes the graphite in gray cast iron evenly distributed, reduces the tendency of whitening; and can increase silicon and desulfurize , Improve cast iron quality.
Calcium Silicon Production
It is generally believed that the chemical reaction expression for smelting silicon-calcium alloy is CaO+SiO2+3C→CaSi+3CO↑, but at high temperature, lime and silica first form calcium silicate slag with a lower melting point, which makes the carbon reduction reaction difficult to proceed. The boiling point of calcium is low, and it is easy to volatilize to produce calcium vapor, and SiO2 is reduced to SiO (gas), so the gas discharged from the furnace is CO, Ca (gas) and SiO (gas), and the content of calcium and silicon in the furnace gas The loss is about 10% each. SiO (gas) and Ca (gas) react with carbon when they pass through the material layer, and most of them are converted into CaC2 and SiC. Therefore, the reactivity of carbonaceous reducing agents is very important for smelting silicon-calcium alloys.
Calcium oxide and silica together with carbon generate CaC2 and SiC at high temperature, which is an intermediate product in the production of silicon-calcium alloy. Part of it remains in the slag, so the production of calcium-silicon alloy is smelted with slag. In essence, the methods for industrial production of silicon-calcium alloys are all realized with CaC2 as the transition product. The density of silicon-calcium alloy is slightly smaller than that of slag, and the silicon-calcium alloy is basically concentrated in the upper part of the molten pool during the smelting process, which is the characteristic of smelting silicon-calcium alloy. Special measures should be taken when silicon-calcium alloy is released from the furnace to separate it from the slag.
Calcium Silicon Price in China Market
According to zxferroalloy, the quotations of the national standard calcium-silicon alloy market remained stable this morning. At present, the mainstream quotations of the Ca30Si60 market for calcium-silicon alloys are maintained at around 11,000-112,000 yuan/ton before leaving the factory. Judging from the recent market transactions, the mainstream transaction prices of the calcium-silicon alloy market are Mostly around 11,000 yuan/ton.
Recently, the shipment situation of each factory has been differentiated. The person in charge of a silicon calcium factory said that the recent shipment speed has accelerated, and the inventory has continued to decline, which may be related to the poor production situation in the previous market. Some factories also said that the demand from steel mills is still poor in the near future, market inquiries are unsatisfactory, and the shipment situation is bleak.
Generally speaking, the current calcium silicon market is difficult to deal with high quotations, while raw material prices have risen slightly, and factories are not willing to ship at low prices. Therefore, it is expected that the calcium-silicon alloy market will remain stalemate in the later stage.