Reducing agent for production of industrial silicon

Abstract

The invention provides a reducing agent for production of industrial silicon, which relates to a reducing agent. The reducing agent comprises, by mass, 0 to 100% of a petroleum coke particle and 0 to 100% of a modified petroleum coke particle, wherein the granularity of both the petroleum coke particle and the modified petroleum coke particle is in a range of 5 to 60 mm. The reducing agent has no less than 76% of dry basis fixed carbon, no more than 1% residual ash, no more than 8% of coarse ash, 10 to 16% of volatile matters and no more than 8% of moisture. Compared with a conventional petroleum coke reducing agent, the reducing agent provided by the invention has the following advantages: permeability of the reducing agent is at least doubled, feeding loss and furnace surface burning loss of petroleum coke are reduced by more than 6%, the degree of graphitization at a temperature of 1300 DEG C is decreased by more than 50%, relative resistivity retention time is prolonged by more than 20 min, reductibility is improved by more than 30%, and a furnace age is almost doubled.

Description

technical field [0001] The invention relates to a reducing agent, in particular to a reducing agent for industrial silicon production. Background technique [0002] At present, the main reducing agents used in the smelting of industrial silicon in my country are: petroleum coke, low-ash bituminous coal, charcoal, wood blocks, etc. Charcoal is the most ideal reducing agent. Charcoal has a high porosity of more than 75%, good reactivity, and high resistivity, which is almost 10 times that of any kind of coke, which is conducive to deep electrode insertion. The ash content is about 3%. However, because charcoal is a renewable resource, not only is it expensive to smelt, but also the smelting of industrial silicon by using large charcoal processes will cause great damage to the environment. [0003] At present, various industrial silicon production enterprises have selected petroleum coke to replace part of charcoal to varying degrees, but in the production process, due to the ...

AI Technical Summary

Problems solved by technology

The petroleum coke used in the production process has a large particle size span, and it is a mixture of fine powder to large pieces of petroleum coke, and the proportion of powder coke with a diameter of less than 5mm accounts for more than 50%, which leads to large dust loss of the powder during feeding, and the material surface Large burning loss, poor air permeability, high furnace gas pressure in the furnace, and high surface pore wind speed, resulting in serious furnace flour material running and burning loss, which can reach more than 10%; due to the small resistivity, it is easy to crystallize and graphitize in advance at around 1300 °C It will quickly lead to the difficulty of inserting the electrode down; due to the high pressure of the furnace gas in the furnace, the exhaust of the furnace gas will not be smooth, the melting temperature will increase, and the power consumption will increase. , making it difficult to lower the electrode, and the furnace shovel and the shovel stay in the furnace for too long during operation, resulting in high iron, low output, unsatisfactory product indicators, and short furnace life when the bottom of the furnace rises, etc.

During the production process of large-particle petroleum coke, the resistivity changes greatly, and the petroleum coke loses its reducing effect after the surface is graphitized, which reduces the utilization rate and causes waste of resources