Solventing out crystallization-basic magnesium carbonate percipitation for thorough phosphorus removal from ammonium
Liang Yang1, Jie Qu1, Dandan Gong1
1Faculty of Materials Metallurgy and Chemistry, Jiangxi University of Science and Technology, Ganzhou, China.
Frontiers in Chemistry
|September 5, 2022
Summary
A novel process removes over 95% of phosphorus from ammonium tungstate solutions via crystallization and further purification using basic magnesium carbonate. This achieves deep phosphorus removal, crucial for high-quality ammonium paratungstate production.
Area of Science:
- Chemical Engineering
- Materials Science
- Inorganic Chemistry
Background:
- Scheelite leaching with phosphate generates ammonium tungstate solutions with high phosphorus content.
- High phosphorus levels impede the production of qualified ammonium paratungstate (APT) products.
- Effective phosphorus removal is essential for APT purification.
Purpose of the Study:
- To develop and optimize a novel process for ammonium phosphate recovery.
- To achieve deep phosphorus removal from ammonium tungstate solutions.
- To enhance the quality of ammonium paratungstate products.
Main Methods:
- Crystallization of ammonium phosphate by ammonia blowing and cooling.
- Precipitation of residual phosphorus using basic magnesium carbonate.
- Optimization of reaction conditions including ammonia concentration, temperature, and time.
Main Results:
- Phosphorus crystallization ratio exceeded 95% under optimized conditions.
- Basic magnesium carbonate precipitation achieved over 99% phosphorus removal efficiency.
- Tungsten loss was minimal (<0.22%) during the purification process.
- Final phosphorus concentration in the ammonium tungstate solution was below 10 ppm.
Conclusions:
- The proposed two-step process effectively recovers ammonium phosphate and removes phosphorus.
- Deep phosphorus removal is achievable, meeting stringent requirements for APT production.
- The method offers an efficient and low-loss pathway for purifying ammonium tungstate solutions.
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