Pyrometallurgical calcination of spodumene is a core pre-treatment step in the sulfuric acid-based lithium extraction process. Its essence lies in using high-temperature thermal treatment to disrupt the stable crystal structure of spodumene and initiate a solid-phase reaction with sulfuric acid, converting insoluble lithium into soluble lithium sulfate for subsequent water leaching and extraction.

Spodumene concentrate is fed into a rotary dryer to remove surface moisture from the raw ore, preventing subsequent agglomeration. The ore is then ground to a specific particle size and fed into a rotary kiln for high-temperature calcination.

The cooled spodumene powder (typically requiring further fine grinding) is uniformly mixed with concentrated sulfuric acid to prepare for the solid-phase reaction.

The acidified clinker after the reaction is cooled to room temperature for storage and leaching. Simultaneously, the highly toxic fluorine-containing and sulfur-containing waste gases generated from the reaction are thoroughly treated and purified.

Process Advantages

Wide Raw Material Adaptability: Compatible with various raw materials including lithium mica, spodumene, and lithiophilite, as well as different feed forms such as lump materials and concentrates.

Flexible Process Design: Supports single-line capacities ranging from 3,000 t/a to 40,000 t/a, flexibly matching different production scale requirements. Features compact equipment layout and smooth process flow, facilitating continuous production and system integration.

Intelligent Operation: Supports fully automated operation across the entire process, enhancing operational stability and process traceability.

Energy Saving and Consumption Reduction: Optimized combustion system and furnace insulation structure, equipped with waste heat recovery devices, effectively reducing energy consumption per unit of product. Flexible and selectable heating methods (natural gas/electricity) adapt to different regional energy structures and environmental requirements.