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Application of Lignosulfates in Treatment of Acidic Rock Drainage
Application of Lignosulfates in Treatment of Acidic Rock Drainage |
August 2003 | ||
| Author(s): Zhuang, J.M. and T. Walsh, Noram Engineering and Constructors Ltd. | International Symposium on Hydrometallurgy in Honor of Professor Ian Ritchie, 24-27 August 2003. The Metallurgical Society of CIM, the Minerals, Metals and Materials Society and Society for Mining Metallurgy and Exploration. Paper 5.5 | ||
| Mine: Britannita Mine, British Columbia | Waste Type: ARD | Contaminant(s): metals | Technology Type: Lignor(TM)-ARD |
| Keywords: lignosulfates, aluminum, manganese, lime | |||
| Abstract: The Lignor(TM)-ARD process from Noram Engineering and Constructors Ltd., Vancouver, BC, applies lignosulfonates, byproducts of the sulfite pulping process, to treat acid rock drainage (ARD). Lignosulfonates have been found to protect lime from developing an external surface coating. The addition of lignosulfonates to ARD solutions increases the clotting and settling rate of the sludge, forming stable metal/lignin complexes that retain metal ions and improve the long-term stability of the sludge against leaching. The Lignor process involves metal chelation with lignosulfonates, ARD neutralization by lime to about pH 7, pH adjustment with caustic soda from 9.4 to 9.6, air oxidation to lower the pH to a desired level, and addition of a minimum amount of FeCl3 for further removal of dissolved metals. The Lignor process removed all concerned metals (especially Al and Mn) from the ARD of the Britannia Mine (located at Britannia Beach, British Columbia, Canada) to a level below the regulatory limit. Compared with the high density sludge process, the Lignor process has many advantages, such as considerable savings in lime consumption, greatly reduced sludge volume, and improved sludge stability. | |||
| For more information online: |
Contact: T. Walsh, 604-681-2030, twalsh@noram-eng.com | ||