DESIGN OF COUNTER CURRENT DECANTATION IN COPPER METALLURGY

The counter current decantation had been used since 90 years ago in the hydrometallurgical plant. It is currently adopted by all new hydrometallurgical plants located in the Katanga Province of the Democratic Republic of Congo (Ruashi Mining, Mumi Mining etc.) since it is applicable to all products; but its malfunction can limit the production of the plant. This publication is an upgrade of the publication called “Initiation à la simulation des flowsheet” and gives the procedure of CCD circuit design in the simplest way. In the first chapter, the pulp is characterized using three parameters (mass, volume and specific gravity). This publication gives the mathematical expressions that link the three parameters for the two constituents of the pulp (solid and liquid) and for the pulp. Specially, this publication gives the simplest method to determine the specific gravity of solid when the mineralogical composition of solid is available and the specific gravity of liquid when chemical composition liquid is available. In the second chapter, this publication gives the description of CCD circuit and the mass balance equations of thickener and CCD in the steady state condition. The difference with the first publication “Initiation à la simulation des flowsheet”, the flocculant is considered a solid. In the third chapter, this publication gives the preliminary data to have before the design of the CCD circuit and the method for obtaining the value of these preliminary data (the mixing efficiency, the flocculant consumption, the wash ratio and the set value of the control parameter of underflows). In the fourth chapter, this publication gives the procedure of the cylinder free settling test. The purpose of this chapter is to give the simplest method for obtaining the flocculant consumption and sizing the thickener. In the fifth chapter, this publication gives the old and new methods for obtaining the optimum number of thickeners in the CCD circuit. In the new method, the determination of optimum number of thickener is illustrated through two examples using the conventional thickener and the High Rate Thickener. The last chapter gives the procedure of simulation of CCD circuit with the new method on an Excel spreadsheet through the example.