Block and malleable arsenopyrite hot-pressure sintering: applied implications

A hot-pressure technique was used to sinter block-shaped, malleable, and compact arsenopyrite, based on the purified natural material. The results show that 500 degrees C and 1.0 GPa are the optimum temperature and pressure conditions, while at temperatures below 500 degrees C the product would become powdery or present visible cracks. Electron probe analysis (EPMA), X-ray diffraction (XRD), and Raman tests confirmed the purity of the samples with a molecular formula of Fe(1.00)AS(1.02)S(1.03). The calculated density was 6.2185 +/- 0.0132 g/cm(3), close to the unit cell density of 6.2389 g/cm(3). The sample can easily be machined in a circular truncated cone shape, and used as an autoclave stopper at 440 degrees C and above 40 MPa for 35 h. Sintering results provide a possibility for further research on the electrochemical corrosion of sulfide minerals at high temperature and pressure. The hot-pressure procedure developed here provides a reference and inspiration for sintering other similar samples in this field. (C) 2020 The Author(s). Published by Elsevier B.V.