Application of Terminalia chebula for Removal of Hexavalent Chromium in Chromite Concentrates

Abstract

Hexavalent chromium, Cr(VI) presence in chromite concentrate is a concern due to its environmental unfriendly and carcinogenic nature. Chromite concentrates typically contain Cr(VI) in the range of 2.0 to 4.0 mg-Cr/kg. The conventional methods of removing toxic Cr(VI) which includes the use of inorganic reductants are generally not preferred industrially due to their unavoidable environment unfriendly and cost ineffective nature. Therefore, in this study the use of Terminalia chebula, which is a naturally occurring organic product, is explored for Cr(VI) removal in chromite concentrates. The parameters in critical Cr(VI) removal process such as Terminalia chebula dosages, contact time and water requirements for application of this method are estimated and used at plant scale. It was found that 540 g of Terminalia chebula and contact time of 120 s is required for one ton concentrate treatment at plant for minimizing Cr(VI) to trace levels of 0.02 mg-Cr/kg. It was also observed that the water requirements in using Terminalia chebula method are insignificant. The application of Terminalia chebula for removing Cr(VI) in chromite concentrate is found to be suitable method for using in continuous production process of chromite concentrates at plant.