Simplified batch clarification of liquid ammonium polyphosphate

摘要

Particulate carbonaceous matter in ammonium polyphosphate liquid made from impure wet-process phosphoric acid is removed batchwise by intimately mixing the liquid with a combination of selected organic flocculating agents and then allowing the mixture to separate. The particulate carbonaceous matter floats and the clarified liquid is withdrawn from the bottom of the separation vessel. The particulate carbonaceous matter, a minor portion of the input ammonium polyphosphate liquid, and the flocculating agents are intimately remixed with fresh black ammonium polyphosphate liquid to allow reuse of flocculant not combined with the original particulate carbonaceous material. The flocculants may be reused as many as five times. The particulate carbonaceous matter, the inactive flocculant, and a minor portion of the input ammonium polyphosphate liquid are then processed into fluid or solid fertilizers. In some instances, more flocculant is added to the mixing vessel.