Abstract

ANDERSON, C.J.; RABIE, S.L.  and  JANSEN VAN RENSBURG, N.K.. Optimization of the Rössing countercurrent decantation circuit for high-calc ore. J. S. Afr. Inst. Min. Metall. [online]. 2018, vol.118, n.2, pp.109-117. ISSN 2411-9717.  https://doi.org/10.17159/2411-9717/2018/v118n2a3.

The Rössing Uranium countercurrent decantation (CCD) circuit is scheduled to process ore with a high calc index from 2017 to 2021. This material was found to be associated with poor settling performance in the CCD circuit. In order to quantify the root causes of the poor performance, bench-scale test work was conducted on the thickener feed. Thickener feed density and process control were identified as key areas for optimizing performance. Two alternative feedwell designs were developed; a simple shelf design and a forced dilution design. An automated control system was also devised to improve the consistency of underflow densities and overflow clarity. These modifications are currently being phased in at Rössing, with the process control upgrades and the feedwell on the terminal thickener being prioritized.

Keywords : countercurrent decantation; optimization; process control thickener; feedwell design.

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