Characterisation of copper and zinc precipitates in DAS treatment systems using electron microscopy and X-ray microtomography

Summary

The University of Huelva is procuring a service to characterise copper and zinc precipitates formed in passive DAS treatment systems in the Iberian Pyrite Belt using high-resolution transmission electron microscopy (HRTEM) and X-ray microtomography (micro-CT). The work includes preparing about 30 FIB lamellae less than 100 nm thick, an estimated 150 hours of TEM equipment use, EDX and EELS analyses, three-dimensional examination of precipitates and porous structures, and mineralogical and geochemical interpretation. The equipment must meet the minimum specifications in the tender documents. The HRTEM must operate at 300 kV, with point-to-point TEM resolution of ≤0.08 nm and HAADF-STEM resolution below 0.10 nm; spherical-aberration correction, a Schottky X-FEG source or better, a Gatan Imaging Filter or equivalent with a simultaneous spectral window up to 2,000 eV, EDX collection solid angle of at least 0.7 sr, and electron-tomography capability are required. The service must produce atomic-resolution images at ≤0.07 nm. The micro-CT must achieve spatial resolution of ≤0.7 μm (700 nm voxels) and provide absorption and advanced phase contrast, multi-scale scanning from samples several centimetres across to regions of about 50 μm without loss of resolution, a temperature-controlled stage from cryogenic temperatures to +200°C, in-situ mechanical testing, a continuous-flow cell, and 3D reconstruction with automatic deep-learning segmentation (Dragonfly or equivalent). The team must include a Technical Director with a doctorate in Geology, Chemistry, Physics or Environmental Sciences, and specialist staff able to operate the required microscopes, perform EDX and EELS analyses, and interpret comparable mineral precipitation systems. For each sample, the contractor must provide a signed and sealed electronic report within 30 days of receipt. The report must include analytical methods and results, images, descriptions of mineral phases and porous structure, interpretation and conclusions. The contractor is responsible for transporting the samples to its laboratory and preserving them during transport. The contract lasts up to two years and has a two-year warranty. Defects must be corrected at the contractor’s expense during the warranty period, with a response time of no more than 30 days. The maximum price is €82,550 excluding VAT (€99,885.50 including VAT). Bidders must submit the European Single Procurement Document and the technical and price documentation. Bids must be submitted electronically, signed, and written in Spanish or accompanied by an official Spanish translation.