Recovery of Phosphates and Metals from Phosphate Sludge by Solvent Extraction.

摘要

A solvent extraction procedure was developed on a laboratory scale for recovering trisodium phosphate,zinc,and iron from waste phosphate sludge as separate products. The phosphate sludge is generated from phosphate coating processes. The sludge was dissolved in hydrochloric acid and iron was extracted as ferric chloride by isopropyl ether. Zinc was extracted by di-2-ethylhexyl phosphoric acid in kerosine. Trisodium phosphate was recovered by crystallization from the raffinate. The value of two marketable products is considerably more than the main reagent costs. The process was developed to permit the recycling of materials in this waste and the consequent reduction of stream pollution from this source. (Author)