A contribution to the theory of jigging, Part I: Similarity criteria of the motion of jig layers

A harmonic pulsion superimposed by a constant hutch water flow serves as the model case in the derivation of similarity criteria of the motion of jig layers. At first the decisive portion oF the jig bed is identified and characterized by two hydraulic properties, i.e. the initial acceleration and th...

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Bibliographic Details
Published inMinerals engineering Vol. 9; no. 6; pp. 675 - 686
Main Author Steiner, H.J.
Format Journal Article
LanguageEnglish
Published Oxford Elsevier Ltd 01.06.1996
Elsevier Science
Subjects
Applications of mathematics to chemical engineering. Modeling. Simulation. Optimization
Applied sciences
Chemical engineering
Exact sciences and technology
gravity separation
Mineral processing
modelling
modelling
gravity separation
Mineral processing
Inorganic industry
Gravity separation
Modeling
Jigging
Ore treatment
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Summary:A harmonic pulsion superimposed by a constant hutch water flow serves as the model case in the derivation of similarity criteria of the motion of jig layers. At first the decisive portion oF the jig bed is identified and characterized by two hydraulic properties, i.e. the initial acceleration and the terminal settling velocity of the separating layer at the cut position. A concise differential equation of the motion of jig layers is formulated and solved for the velocity function and the displacement function. In the normalized versions of the said functions, two main dimensionless similarity criteria of the motion of a jig layer are identified. One of the criterions is the lift-off angle, i.e. the phase angle at the beginning of the displacement of the jig layer. The second criterion comprises a modified Froude-number. The latter relates the maximum acceleration of the fluid to the initial acceleration of the separating layer, thus combining a characteristic of the pulsion with a characteristic of the jig bed. Additional dimensionless parameters characterize the flow regime and the degree of suction. Empirical knowledge about the average settings of jigs is summarized in average values of the said similarity criteria. All the equations are derived from basic hydraulics and observe the requirement of dimensional homogeneity.
ISSN:0892-6875
1872-9444
DOI:10.1016/0892-6875(96)00055-6