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Background Phosphogypsum is a waste product from production of phosphorus and is stored in a containment pond. Phosphogypsum wastewater still contains a usable amount of phosphorus. In addition to phosphorus, this water contains a small amount of arsenic, which prevents direct use of this water in agriculture. Method Recycling of phosphorus from phosphogypsum wastewater was performed by struvite (NH4MgPO4•6H2O), precipitation. Arsenostruvite (NH4MgAsO4•6H2O) has always occurred naturally in the presence of struvite. The properties of arsenostruvite in comparison with struvite were monitored. The effect of selected reductants (SnCl2, ascorbic acid, K2S2O5) on the potential of reducing the concentration of As in the struvite crystallized from phosphogypsum wastewater, was monitored. Findings When recovering phosphorus from phosphogypsum wastewater in the form of struvite the results showed that a ratio of As to P was lower by 50% compared to the original wastewater. K2S2O5 proved to be the most effective reducing agent for reducing the arsenic content of the product, but it was still not sufficient for the product to be used as a fertilizer without any further treatment. |
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