Characteristic pollutant purification analysis of modified phosphogypsum comprehensive utilization

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Phosphogypsum (PG) is a waste product from phosphoric acid production.
• PG storage occupies land and poses environmental risks.
• Developing sustainable reuse methods for PG is crucial.

Purpose of the Study:

• Investigate the reuse of calcination-modified PG as a building material.
• Study the mechanism of PG calcination modification.
• Assess the environmental risks of modified PG.

Main Methods:

• Experimental research on PG calcination modification.
• Analysis of crystal phase transformation and impurity removal.
• Environmental risk assessment using leaching toxicity tests.

Main Results:

• Calcination at 280 °C for 5 h modified PG's crystal phase, removed impurities, and adjusted pH to 7.1.
• Soluble fluorine and phosphorus removal rates reached 69.2% and 71.2%, meeting China's national standard.
• Leaching toxicity of heavy metals in modified PG was well below national limits.

Conclusions:

• Calcination modification effectively transforms PG into a safe material.
• Modified PG shows significant potential for use in cast-in-place concrete products.
• This research offers a sustainable solution for phosphogypsum waste management.