Hydrometallurgical Recovery of Iron, Nickel, and Chromium from Stainless Steel Sludge with Emphasis on Solvent Extraction and Chemical Precipitation

Stainless steel has a variety of applications nowadays because its mechanical strength and corrosion resistance. The large-scale machinery made up stainless an outstanding performance endurance for manufacturing industries. However, scraps accumulate with lubricant to form sludge during the operation. To reduce environmental hazards caused by sludge, this research attempts construct hydrometallurgical process recover iron, nickel, chromium from sludge. experiments could be divided into four parts. First, calcination was adopted remove oil water content. factors that have impacts on leaching efficiency, such as type acid temperature, were investigated in second part. It optimal calcined at 300 ? 8 h leached 4 mol/L HCl. results revealed percentages 97.6%, 98.1%, 95.7%, respectively. In two-stage solvent extraction procedure, Fe(III) efficiently recovered using 0.1 bis(2-ethlhexyl) phosphate (D2EHPA) pH 1.5 Aqueous/Organic ratio 1 over 10 min. indicated percentage beyond 99%. Eventually, recoveries nickel respectively 99.5% 75% through chemical precipitation.