Sustainable Mining and Metallurgy

Lithium smelting mostly uses lepidolite and spodumene as raw materials, and pyrometallurgical smelting is carried out in a rotary kiln. The generated flue gas contains a large amount of heavy metal dust, SO₂ and NO_x. Taking the flue gas purification of rotary kiln of a 50000t/a battery-grade lithium salt project as the object, the characteristics of lithium smelting flue gas were explored, and the high-temperature dust-nitrate integration combined with sodium-alkali desulfurization process was selected to purify the flue gas. The process flow, system configuration and core design parameters were described in detail, and the field operation data were provided. After the flue gas is dedusted, denitrified and desulfurized by this process, the SO₂ concentration of the net flue gas at the outlet of the device is lower than 100mg/Nm₃, the NOx concentration is lower than 100mg/Nm₃, and the dust emission concentration is lower than 10mg/Nm₃. The parameters meet the ultra-low emission requirements, which provides a reference for the design of flue gas purification in similar lithium industry.