| 摘要 |
<p>A treatment of metallurgical dust and recovery of valuable chemical commodities, comprising the steps of: leaching salts from the dust with water to create a washed EAF dust; reacting the washed EAF dust in a nitric acid solution resulting in a nearly complete dissolution of the zinc, cadmium, copper, magnesium, calcium, manganese and lead from a filtrate; removing iron from the filtrate by raising pH in the system with basic zinc carbonate; removing cadmium, copper and lead in an electrolytic cell, where copper and cadmium are collected at the cathode, and lead is collected at the anode; evaporating and decomposing the filtrate to obtain metal oxides and anhydrous calcium nitrate; leaching the solid residue with water to separate calcium nitrate in a marketable form; removing the zinc from the magnesium and manganese by leaching the residue with an amine solution; stripping the filtrate of ammonium carbonate to yield zinc precipitated as a zinc oxycarbonate; dividing the zinc oxycarbonate into a first stream and a second stream by reacting the zinc complex with acid to produce a zinc product, the first stream serving as a pH adjuster to precipitate iron, the second stream preparing highly pure zinc products for sale; and, separating a residue containing magnesium and manganese by dissolving magnesium in acid, whereby liquid filtrate contains marketable magnesium nitrate or sulfate. The nitric gases given off during the steps are recycled to nitric acid by a nitric recycle.</p> |
