Urea–Ammonium Nitrate Aqueous Solutions Containing Cu Micronutrient Obtained from Cable Manufacturing Solid Waste

In this work, sustainable metal recovery from waste and conversion into Cu-micronutrient-containing N fertilizers was developed utilizing the HNO 3 extraction method. For this purpose, solubility diagrams, i.e., polytherms, were constructed of the ternary CO(NH 2 ) 2 -Cu(NO 3 ) 2 -H 2 O and NH 4 NO 3 -Cu(NO 3 ) 2 -H 2 O systems to determine the corresponding phase equilibria and solid material chemical composition. Copper extraction in the form of water-soluble Cu(NO 3 ) 2 was performed from the industrial Cu cable manufacturing waste, using HNO 3 concentrations relevant to the industrial conditions (56–58%) at a moderate temperature of 60 °C. Waste dissolution in aqueous NH 4 NO 3 solutions resulted in only partial dissolution of <60% after 30 min. Processes of Cu and Zn micronutrient extraction from solid waste and integration into the existing NH 4 NO 3 and nitrophosphate (NP and NPK) production technologies was proposed via an additional HNO 3 dissolution step, combined with the solid unreacted residue removal.