Phosphorous contained in the by-product sludge from phosphorous production is converted to sodium phosphinate via alkaline digestion in an agitator reactor. The digestion suspension product contains contaminants from the sludge and is, therefore, filtered prior to further processing. The liquid resulting from the centrifugation is recycled to the process. Elimination of heavy corrosion costs.
Phosphine gas emitted from reactor is utilized in phosphorous acid plant.