HYDENS TECHNOLOGY SOLUTION PERFORMANCE AND INDUSTRIAL APPLICATIONS

For several years, Rio Tinto Alcan has been involved in the development of solid-liquid separation technologies, which represent one of its strategic development portfolios. Improving the performance of residue thickeners is important both in terms of plant production as well as in terms of environmental footprint reduction. In the current economic context of limited capital availability, options providing improved performance at low cost are welcome by all industries. The HyDens^TM technology solution was developed to allow high underflow solids concentration materials to be generated and extracted from conventional flat bottom thickeners, maximizing their performance and bringing benefits of paste thickeners without the need for expensive conical bottom tank construction. This technological solution is found to be readily adaptable to existing tanks and its implementation can be done within the normal tank turn around cycle. The HyDens^TM technology solution is applicable to tanks used in various stages of solid/liquid separation processes and have been tested on bauxite, hydrotalcite, nickel, boron and copper residues materials. This paper will present the major steps in the development of HyDens^TM technology solutions. Laboratory and pilot results will be presented and some key mechanical design elements will be discussed. An example of an industrial application at the Alteo Gardanne alumina refinery will also be presented.