Optimization of wet-process phosphoric acid for high-quality phosphogypsum
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1
School of Chemical and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430073, China
2
Key Laboratory for Green Chemical Process of Ministry of Education, Wuhan Institute of Technology, Wuhan 430074, China
3
Research and Development Center, Hubei Three Gorges Laboratory, Yichang 443007, China
4
Hubei Yangtze Resources Recycling and Equipment Innovation R&D Center Co., Ltd, Wuhan 430223, China
Publication date: 2024-09-05
Corresponding author
Hong Zhou
School of Chemical and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430073, China
Physicochem. Probl. Miner. Process. 2024;60(5):192938
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ABSTRACT
The chronic accumulation of phosphogypsum (PG) has resulted in significant environmental contamination issues within the wet-process phosphoric acid (WPPA) industry. An innovative technical route for transforming PG into a resource has been achieved through the introduction of floc flotation and acid cleaning in WPPA. The floc flotation using cationic polyacrylamide as a flocculant and micro lotion, which is composed of dioctyl phthalate, polyoxyethylene(10)nonylphenyl ether, kerosene, and n-octanol as a collector, has been performed. The effect of floc flotation on product quality and the underlying mechanisms were investigated by XRF, FT-IR, SEM, and 2-dimensional fractal dimension analysis. The optimal parameters were determined through a factor experiment, which yielded the following results: floc flotation temperature 65 ℃, cationic polyacrylamide 180 g/Mg, collector 1.08 kg/Mg, and flushing sulfuric acid concentration 20%. The resulting PG exhibited a high grade of 95.01%, whiteness of 70.8%, and gypsum recovery of 93.52%. Furthermore, the soluble phosphorus and soluble fluorine levels are below 0.1%. In the flotation process, the combination of polyacrylamide and collector effectively separated fine organic matter and siliceous material with a hydrophobic bubble, facilitating their upward movement and subsequent separation from PG. The new WPPA, which exhibits enhanced product quality and reduced production costs, can be utilized extensively within the WPPA.