The reduced ilmenite obtained through processes such as carbon blending, reduction roasting, screening, and magnetic separation is used in the production of artificial rutile and electrode coatings by the corrosion method. The reduced ilmenite products obtained by reductive roasting of ilmenite in a rotary kiln have a broad market prospect for use in the welding electrode industry.
1. Metering and mixing: Carbon (coal) is blended based on the quality of ilmenite, with the total coal blending amount accounting for about 50% of ilmenite, with coal for mixing and coal for kiln head injection accounting for about 25% each. The main function of coal injection at the kiln head is to meet the temperature requirements of various sections in the kiln and ensure a reasonable reduction atmosphere in the kiln.
2. Rotary kiln reduction roasting: The reduction roasting of ilmenite in the rotary kiln should be carried out under positive pressure, and the temperature, atmosphere, and roasting time in the kiln should be controlled.
3. Dust removal of roasting tail gas: After heat exchange, the roasting tail gas is sent to the bag dust collector, and the temperature of the flue gas sent to the bag dust collector should not be greater than 180 ℃. The dust removal powder is recycled and the flue gas is sent to the SO2 absorption system after dust removal.
4. Treatment of SO2 from roasting tail gas: The tail gas from reduction roasting of ilmenite is absorbed by a two-stage leaching tower, and the absorption liquid is absorbed by lime slurry (or alkali liquor to produce sodium sulfite).
5. The reduced ilmenite after being discharged from the kiln should be cooled in a timely manner, and secondary oxidation of the reduced ilmenite should be prevented during the cooling process. Rapid cooling is conducive to ensuring the quality of the reduced ilmenite.
6. Screening and magnetic separation of reduced ilmenite: The reduced ilmenite after cooling out of the kiln shall be screened and magnetic separated, and the qualified reduced ilmenite after screening and magnetic separation shall be metered, packaged, and warehoused. The unburned coal char is returned to the batching system in the raw material and continues to be used as a carbon reducing agent in the kiln.