Refractory for Ferrosilicon Furnace

Ferrosilicon furnace are high-energy-consuming industrial electric furnaces, belonging to the category of submerged arc furnaces.

A ferrosilicon smelting furnace consists of a furnace shell, furnace cover, furnace lining, short mesh, water cooling system, flue gas system, dust removal system, electrode shell, electrode pressing and lifting system, loading and unloading system, handle, burn-through device, hydraulic system, transformer, and various electrical equipment. The refractory materials used are also quite demanding.

Ferrosilicon smelting furnace mainly produce ferrosilicon, ferromanganese, ferrochrome, ferrotungsten, and ferrosilicon-manganese alloys. Production is carried out through continuous feeding and intermittent slag removal, making it a continuous-operation industrial electric furnaces.

Refractory Materials for Ferrosilicon Furnace

Ferrosilicon industrial electric furnaces are high-energy-consuming furnaces. Reducing energy consumption, increasing output, and extending the furnace's lifespan are crucial for reducing production costs and minimizing waste pollutant emissions.

The following section introduces different refractory material application schemes for different reaction temperatures in ferrosilicon submerged arc furnaces for reference only.

New Material Preheating Zone: 

The top 500mm layer, with temperatures ranging from 500℃ to 1000℃. This zone experiences high-temperature airflow, electrode conduction heat, combustion of the surface charge, and resistance heat from the current distributed in the charge. Temperatures vary in this area, and it is lined with clay bricks.

Preheating Zone: 

After moisture evaporates, the charge gradually descends and undergoes initial changes in the preheating zone, including a silica crystal transformation and volume expansion, eventually leading to cracks or bursts. The temperature in this section is around 1300℃. It is constructed with high-alumina bricks.

Sintering Zone: 

This is the crucible shell, with temperatures ranging from 1500℃ to 1700℃. Liquid silicon and iron droplets are generated and fall into the molten pool. Sintering of the charge is difficult, and permeability is poor. Blocks should be broken up to restore gas flow and increase resistance. This area is hot and highly corrosive. It is constructed with semi-graphite carbon-silicon carbide bricks.

Reduction Zone: 

This zone involves intense chemical reactions of numerous materials. The crucible area temperature ranges from 1750℃ to 2000℃. The lower part is connected to the arc cavity, primarily for the decomposition of SiC, the formation of ferrosilicon, and the reaction of liquid Si₂O with C and Si. This high-temperature zone is constructed using semi-graphite calcined carbon bricks.

Arc Zone: 

Located in the cavity at the bottom of the electrode, this zone has a temperature exceeding 2000℃. This is the highest-temperature zone in the entire smelting furnace and the source of the most significant temperature distribution. 

Therefore, if the electrode is inserted shallowly, the high-temperature zone shifts upwards, resulting in a lower furnace bottom temperature and less slag removal, forming a false furnace bottom. This causes the taphole to shift upwards. A certain degree of false furnace bottom provides some benefit for furnace protection.

Generally, the electrode insertion depth is closely related to the electrode diameter. A typical insertion depth should be maintained at 400mm-500mm from the SAF smelting furnace bottom. This area has even higher temperatures and is constructed using semi-graphite calcined carbon bricks.

The permanent layer is constructed using phosphate concrete or clay bricks. The furnace door area of the industrial electric furnaces can be lined with either corundum castable or pre-laid with silicon carbide bricks.

In short, the appropriate, environmentally friendly refractory bricks and castables of different materials should be selected for the lining based on the size, temperature, and degree of corrosion of the ferrosilicon furnace.

For any questions or needs regarding the smelting of ferrosilicon, manganese, and other non-ferrous metals in submerged arc furnaces, please feel free to contact Sanrui Electric Furnace for one-stop turnkey engineering services!