Electrokinetics and Flocculation Studies of Coal
Nikhil Dhawan* *Punjab Engineering College,
Deemed University, Chandigarh-160012 dhawan.nikhil@gmail.com
Abstract
Indian Coal contains high ash content around 25-35%. If it’s not treated before using in the steel plant or in blast furnace, it will lead to some problems like high slag volume, lower calorific value and lesser strength of coke, which is made in coke ovens from coal. So washing of coal is done to remove ash content, But the problem arises when coal is washed it retains some water along with it which makes it difficult to process as it reduces heating value, increases transport costs and also makes handling difficult.
Mechanical dewatering is done by some means like pressure filtration, vacuum filtration and centrifugal filtration. But significant portion of solids goes along with water in effluent stream and rest remains in centrifuge during mechanical dewatering. Thus there is need of recovering those solids and water also which can be further used in the plant. Also filtration rate should be high and it should settle down the solids in good amount. This paper reports determination of Iso Electric Point, to find out best flocculent along with its optimum dosage required for
flocculation by considering many factors such as turbidity of supernatant, faster settling, volume settled (Compactness) and moisture content. For this reason flocculation is employed and optimal conditions for flocculation are obtained from electro kinetic studies of coal centrate samples i.e. determination of PZC (point of zero charge) at this pH value there is no charge, so there will be no repulsion between particles and thus are not in dispersed form and thus filtration is easier and faster. The coal sample used is coal centrate sample of size –37 microns from Tata steel Jamshedpur.