Design of Flexible Configuration Nodule Processing Pilot Plants In the Context of Evolving Metal Markets Available to Purchase

The demand supply scenario in the metal markets present a continuous change because of globalisationand environmental concerns implying additional capital cost for improving procespsing facilities. A review of the current demand supply in Indian scenario as well as the world scenario with respect to the principal value metals in nodules (Ni, Co, Cu and Mn) leads to considerations of pilot plant design which would have flexible configuration for catering to multiproduct outlets. Although both pyrometallurgical and hydrometallurgical processes for nodules treatments have been examined and piloted, it is necessary to look into the various process alternatives· for attaining multi-product configurations. For example, new reagent for metal separation, particularly, Co and Ni separation leads to the possibility of producing synthetic Ni-Co bearing solutions containing small quantities of Ni which after precipitation can find its way into the global market. Scaleup of various equipment to an envisaged capacity of 1.5 MDTPA would require considerable effort as is clear from scale-up of strategy adopted for certain equipment during processing of laterite ores. The paper describes a number of options available for the processing of polymetallic nodules where the product can be sent to external centralised processing facilities for further value addition. The pilot plant configuration for testing polymetallic nodules processing routes also need to be made flexible enough to look into such various possibilities. It is suggested that future pilot plant facilities should be so designed so that front end of the various process can be scaled-up to commercial sized operations. However, solution treatment routes for producing multi-products can be designed to operate at much smaller scale, thus cutting down the cost of piloting. In this context, provided that the economies of scale permit, the capital cost for" nodules processing plants also need to be re-assessed.