The Progress of the TAILCO process

 

2 December, 2024

The TAILCO process aims to valorise secondary cobalt resources produced in the hydrometallurgical plant of Cobre Las Cruces (CLC). To this goal, TAILCO works on the development and implementation of a new technology to valorise cobalt and zinc contained in the raffinate generated in the CLC industrial plant after copper recovery. Raffinate is a liquid residue from the hydrometallurgical process, which contains interesting concentrations of cobalt and zinc in aqueous sulphuric acid media. Both elements, cobalt and zinc, are considered for recovery as they report an important economic value for the project. In addition, cobalt is of great interest as it is considered as one of the critical raw materials for Europe.

The concept is to integrate the processing of the copper raffinate in the existing facilities recycling exhausting solutions to the main plant processing circuit. In this way, TAILCO revalorise a liquid residue and allows a zero-waste approach. This new technology would be used in another hydrometallurgical processing plant by adapting process conditions to the particular conditions of the process streams to be treated.

The process, developed by CLC and CETAQUA, covers four different sub-processes:  nanofiltration to recover sulphuric acid, iron removal to purify the solution, cobalt cementation and zinc recovery for metals production. During the first period of the project, lab fine-tuning activities have been already performed by CLC for three sub-processes. Several sets of laboratory tests were developed for iron removal, cobalt cementation and zinc recovery in order to determine the optimal operating conditions for each one. It must be highlighted that favourable results and recoveries were achieved in all of them at laboratory scale. CETAQUA has been working in parallel for the development of the nanofiltartion stage at lab scale using open and closed circuit approachs.

The TAILCO process will be subsequently run and scaled-up in a future pilot plant in order to validate this technology. To this aim, CLC and CETAQUA are currently cooperating with the METALLICO coordinator IDENER in the pilot plant engineering: the entire process has been completely defined, the process diagrams have been completed, the process drawings have also been finished and necessary equipment and instrumentation have been defined and specified.

Next period, CLC will continue working in the assemble and construction of the TAILCO pilot plant in their facilities to treat secondary resources for overall process demonstration. Once the installations will be ready, the pilot plant will be commissioned and operated to scale up the TAILCO process and demonstrate and validate the technology.

Simultaneously to the pilot, products obtained during its operation will be physicochemical and mineralogical analysed and characterised in order to assure the end-users’ specifications.