Development And Applications Of A Tilting Narrow Flowing Classifier In Wet Grinding Close-Circuit

DEVELOPMENT AND APPLICATIONS OF A TILTING NARROW FLOWING CLASSIFIER IN WET GRINDING CLOSE-CIRCUITOf classifiers widely applied in wet grinding close-circuit, spiral classifier with compact structure is less complicated and more convenient for applications but offers low level of classification quality (LCQ); hydro-cyclone gives high productivity per unit of floor area and LCQ but requires very critical work conditions and high operating cost.On demands of market at home and abroad, to develop a new Tilting Narrow Flowing (TNF) classifier which has the advantages of both the spiral and the cyclone is the objective of our project.In the Integrated-Elements' TNF classifier, the principle of "Settling in Shallow Layer" has been practiced to lift specific productivity per unit of floor area, and the "Boundary Friction Effect" and Reduced Overfloow Area have been adopted to improve the LCQ or classifying accuracy. These have been realized and documented by feeding pulp classification operation over three years at the Ilmenite Concentrator of the Panzhihua Corp. in Sichuan Province.Optimizations of structure design and operation parameters are needed for TNF classifier applied in wet grinding close-circuit to meet installation requirements, such as plane and height layouts, and operation conditions, such as high pulp density and viscosity, etc.Pilot test on the TNF classifier in wet ore grinding open-circuit of Yunnan Phosphorus Fertilizer Plant achieves an averaged specific productivity of 15.6 m3/m2-h, LCQ of 60.34 %, underflow density of 65.6 % and overflow of 29.6 % of solids with 150 μm as cut-off size. A small-scaled operation over one year in wet grinding close-circuit of a Titanic Coulsonite Concentrator shows that TNF classifier has topped and- replaced a hydrocyclone formerly used, yielding averagedperformances of 7.3 m3/ m2-h (or 2.84 t / m2-h), LCQ of 59.89 %, underflow density of 58.8 %s and overflow of 18.7 %s at a cut-of size of 43um after demagne-tization of feed pulp.High density and -viscosity of TNF pulp, probably caused in wet grinding close-circuit, makes narrow spaces between every two tilting plates tending to gradually silted-up and jeopardizes classifying operation. This problem is planned to solve with further R & D in trial operation.