Measurement of Overflow Density in Spiral Classifiers Using a Vibrating Fork Densitometer with Accuracy Evaluation

Abstract

This work concerns the application of a vibrating fork densitometer to the measurement of overflow density in spiral classifiers. A spiral classifier is a mineral processing equipment which receives an ore slurry input and performs a gravity separation process between the solids particles of ore and the water. The classifier has two outputs: the “underflow”, formed by sedimented coarse solids; and the “overflow”, in the form of an ore slurry with fine suspended solids particles. For proper performance of a spiral classifier, the density of its overflow needs to be controlled by a feeding of dilution water at the input of the classifier. Even in present days, this control is still performed manually from manual samples of the overflow density, due to the lack of a standard instrumentation solution for this application. In this context, this work describes the application of a vibrating fork densitometer for overflow density measurement in spiral classifiers. The instrument performance was evaluated in two steps: a bench testing and a field testing. In both cases, its measurement accuracy was statistically investigated. The results obtained indicated the feasibility of the instrument for the intended application.