Recycling of steel swarf via hydrometallurgy. Purification of iron chloride solution via solvent extraction, cementation, and ion exchange – a comparative study
Typ
Examensarbete på grundnivå
Program
Publicerad
2021
Författare
Saami, Melis Yudzhel
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Several methods for purification and recovery of metals present in a swarf solution obtained from steel production and manufacturing waste are being tested in this study. The valuable elements originally present in the waste are Fe, Mn, Ni, and a small amount of Cr. The purification methods include solvent extraction with acidic and solvating extractants, cementation with an iron plate and ion exchange with the chelating resin Dowex M-4195. The extractants Cyanex 272 and D2EHPA extracted the highest amounts of Fe in comparison to the other acidic extractants. Both Cyanex 272 and D2EHPA reached 45% of Fe extraction at pH=3. Coextraction of Mn and Ni did occur in both cases indicating that solvent extraction is not the best approach for purification of the swarf. The solvating extractants TBP, Cyanex 923 and Aliquat 336 were tested at the same conditions, without adjusting the pH. Cyanex 923 extracted mostly Fe that reached 14% with less than 1% co-extraction of Mn and Ni. TBP and Aliquat 336 were inefficient in this case. A cementation technique with a piece of iron plate did not give any significant difference in metal concentration before and after the experiments. The best results are obtained from the ion exchange experiments with Dowex M-4195 at 25°C, 40°C and 60°C, shaking speed at 150 rpm for a total of 4h. Increasing amounts of Ni adsorption were observed at higher temperatures and longer shaking time. More than 95% of Ni got adsorbed by the resin at 60°C after 4h, the absorption reached 96% at room temperature after 48h. Co-extraction of the other metals decreased with increasing temperature concluding that ion exchange at temperatures above 40°C is the best method for purification of the swarf in comparison to solvent extraction and cementation.