Phosphoric Acid Decomposition of Scheelite

At present, the decomposition methods of scheelite mainly include acid method, soda method and NaOH method.

The acid decomposition method mainly uses hydrochloric acid to treat scheelite concentrate. Thermodynamic studies show that the reaction trend is very high. During decomposition, tungsten forms tungstic acid precipitation, calcium forms calcium chloride solution, and then filters and extracts tungsten after decomposition. However, when hydrochloric acid is decomposed, tungstic acid is coated in yellow colloidal form on the surface of undissolved scheelite, which easily leads to incomplete decomposition. Moreover, the acid corrosion and volatilization of hydrochloric acid are serious, and the working environment is bad. Finally, a large amount of residual hydrochloric acid mother liquor is discharged through lime neutralization and CaCl2 solution. At present, it has been abandoned in China.

At present, the decomposition methods of scheelite mainly include acid method, soda method and NaOH method.

The acid decomposition method mainly uses hydrochloric acid to treat scheelite concentrate. Thermodynamic studies show that the reaction trend is very high. During decomposition, tungsten forms tungstic acid precipitation, calcium forms calcium chloride solution, and then filters and extracts tungsten after decomposition. However, when hydrochloric acid is decomposed, tungstic acid is coated in yellow colloidal form on the surface of undissolved scheelite, which easily leads to incomplete decomposition. Moreover, the acid corrosion and volatilization of hydrochloric acid are serious, and the working environment is bad. Finally, a large amount of residual hydrochloric acid mother liquor is discharged through lime neutralization and CaCl₂ solution. At present, it has been abandoned in China.

When tungsten in solution is extracted by ion exchange and solvent extraction, tungsten is adsorbed in the form of phosphotungstic heteropoly acid. The remaining phosphoric acid in solution is returned to leaching. When ammonium salt precipitation method is used, tungsten can be precipitated in the form of ammonium Phosphotungsten heteropoly acid. The remaining phosphoric acid and a small amount of tungsten in solution are returned to leaching, which simplifies the operation and reduces the leaching cost. The cost. After the reaction, the remaining solution can be basically recycled without pollution, saving resources and energy consumption.

• < Prev
• Next >