In December 2019, our company successfully tested a pilot plant designed for low-temperature acid roasting of rare earth concentrate using an externally heated rotary kiln. The system operated continuously for over 72 hours, meeting all design requirements with stable process parameters and qualified product indicators, earning unanimous recognition from the owner.

This pilot plant is a collaborative effort between our company and Northern Rare Earth Group, organized by the Northern Rare Earth Technology Center. Xi'an Sanrui Industrial Co., Ltd. was responsible for development, design, manufacturing, and installation. The test site is located at the Northern Rare Earth (Huamei) Smelting Plant No. 1.

The pilot plant is specifically designed to address the characteristics of the sulfuric acid method for rare earth acid roasting. It fully utilizes the advantages of the externally heated rotary kiln, incorporating a structure that prevents material buildup on the walls. This innovative design solves several key issues, including high sulfuric acid consumption, corrosion, ring formation, poor furnace sealing, large exhaust gas volumes, high dust content, and the inability to recycle materials during the rare earth acidification process.

The successful testing of this low-temperature acid roasting facility demonstrates that the process route for acid roasting using externally heated rotary kilns is both reasonable and feasible. This breakthrough represents significant progress in the sulfuric acid method for rare earth acidification and lays a solid foundation for upgrading smelting process equipment and core facilities used for rare earth concentrate.