Converting leather chrome shaving waste into free-chrome char as a fuel

Document Type : Original Article

Authors

1 Wool Production and Technology Department, Desert Research Center, Cairo, Egypt

2 Department of Agricultural Biochemistry, Faculty of Agriculture, Al-Azhar University, Cairo, Egypt

Abstract

Chrome shaving wastes (CSW) are categorized as solid wastes with large quantities in tanneries, causing environmental damage when disposed by incinerating or landfilling. This study focused on converting CSW into free-chrome char that could be used as a fuel for energy production allowing recycling of recovered chrome again in leather processing. In this study, CSW were carbonized by incineration or pyrolysis at different temperatures (400, 500, 600 or 700℃). Thereafter, chrome was recovered from char using sulfuric, hydrochloric, or nitric acids at three level of concentrations (0.2M, 0.6M and 1.0M), soon after the recovered chrome was re-used for tanning pickled sheep skins’ samples. The results showed that char yield was improved in pyrolysis and by the lowest temperature. Additionally, the increment in acid concentration and using sulfuric acid had the best effect for chrome recovery. Therefore, CSW pyrolysis at 400℃ produced the highest char yield (44.58%) with chrome recovery rate of > 88% when using sulfuric acid with concentration ≥ 0.6M. The produced char contained 5172 kcal/kg that could be used as fuel, as well as the recycled chrome was successfully re-used in leather tanning process with no changes in leather properties as compared with traditional chrome tanning.

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Volume 65, Issue 13 - Serial Number 13
Special Issue: Chemistry and Global Challenges
December 2022
  • Receive Date: 17 May 2022
  • Revise Date: 24 June 2022
  • Accept Date: 28 June 2022
  • First Publish Date: 28 June 2022