title: Studies on rheological and leaching characteristics of heavy metals through selective additive in high concentration ash slurry.
abstract: The generation and disposal level of thermal power plant ash in India is a challenging task. The conventional mode of dilute phase ash slurry (10-20% solids by weight) transport through pipelines being practiced in majority of these plants not only consumes huge amount of precious water and pumping energy but also causes serious environmental problem at the disposal site. The present study investigates the rheological and leaching characteristics of an Indian ash samples at high solids concentrations (>50% by weight) using sodium silicate as an additive. The flow behaviour of ash slurry in the concentration range of 50-60% by weight is described by a Bingham-plastic model. It was indicated that the addition of sodium silicate (0.2-0.6% of the total solids) could able to reduce both the slurry viscosity and the yield stress. The analysis of the ash samples for the presence of heavy metals such as Fe, Cd, Ni, Pb, Zn, Cu, Co, As and Hg were carried out following Hansen and Fisher procedure. The addition of sodium silicate affected the leaching characteristics of the ash samples over a period of 300 days resulting in the reduction of leaching of heavy metals.
authors: Institute of Minerals and Materials Technology, Council of Scientific & Industrial Research, Bhubaneswar 751 013, India. pksenapati@immt.res.in
authors: P K
authors: PK
authors: Senapati
authors: R
authors: R
authors: Mohapatra
authors: G K
authors: GK
authors: Pani
authors: B K
authors: BK
authors: Mishra
mesh_terms: D060729:Coal Ash / Q000032:analysis* / Q000737:chemistry; D003246:Conservation of Energy Resources; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry; D007220:Industrial Waste / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis* / Q000737:chemistry; D012212:Rheology; D017640:Silicates / Q000737:chemistry; D014783:Viscosity
chemical_list: D060729:Coal Ash; D004785:Environmental Pollutants; D007220:Industrial Waste; D019216:Metals, Heavy; D017640:Silicates; C005691:sodium silicate