Leaching Characteristics of Vanadium with Assistant in Sulfuric Acid from Titano-Magnetite

摘要

The recovery of vanadium with calcium fluoride in sulfuric acid medium was put forward from vanadium titano-magnetite in order to enhance the leaching efficiency of vanadium and reduce the environmental pollution. The main factors, leaching mechanism and kinetics analysis of vanadium from vanadium titano-magnetite concentrate were deeply investigated. The results show that the calcium fluoride could obviously increase the recovery of vanadium and enhance leaching efficiency. The recovery of vanadium was increased from 75% to 92% with 6% calcium fluoride. The calcium fluoride could promote the dissolution of SiO_2 and the generation of H_2SiF_6, which may easily destroy the crystal lattice of magnetite and dissolve the vanadium. The particles of vanadium titano-magnetite were smaller and multihole with calcium fluoride after the acid leaching process. The leaching kinetics could be expressed by the SCM in the process. The apparent rate constant was increased from 0.0017 to 0.0031 with 6% calcium fluoride at 100°C, where the apparent activation energy (Ea) of vanadium leaching has been decreased from 36.05 KJ/mol to 22.17 KJ/mol.