Kunming Metallurgical Research Institute

The Bayer process is the primary method for alumina production. However, thiosulfate ions (S 2 O 3 2− ) present in the involved sodium aluminate solution are difficult to remove and adversely affect this process, thereby limiting the large-scale application of high‑sulfur bauxite. To address this issue, this study designed and synthesized a composite photocatalyst Co-TiO 2 @C based on ZIF-8-derived porous carbon as a carrier. Moreover, the study combined wet oxidation and photocatalytic oxidation to investigate the photocatalytic S 2 O 3 2− degradation activity and stability of this photocatalyst in a sodium aluminate solution. Results indicated that the ZIF-8-derived porous carbon carrier had a high specific surface area and highly porous structure, which were conducive to the loading and dispersion of Co-TiO 2 catalytic components. Moreover, it formed a composite photocatalytic material with good adsorption performance and abundant active sites. High-temperature pyrolysis led to the formation of graphite structures with excellent electron transfer properties on porous carbon supports, while Co doping reduced the bandgap energy of the loaded nano-TiO 2 , resulting in excellent photocatalytic performance of the composite catalyst under visible-light irradiation (The bandgap is 2.78 eV, and the photocurrent density under xenon lamp can reach 2.41 μA/cm 2 ). The adsorption degradation of S 2 O 3 2− ions by Co-TiO 2 @C/900 reached 29.6% within 30 min. After 60 min of light irradiation, the photocatalytic degradation rate of S 2 O 3 2− ions by Co-TiO 2 @C/900 can reach 92.5% under xenon lamp irradiation, which is 38.4% higher than that of P25. Moreover, the degradation efficiency of S 2 O 3 2− ions by Co-TiO 2 @C/900 only decreased by 9.5% after 6 cycles of experiences. The results of quenching experiments and paramagnetic electron resonance indicated that the degradation mechanism of S 2 O 3 2− depended on the generation of reactive oxygen species, such as hydroxyl radicals and superoxide radicals, under light irradiation. • Photocatalytic oxidation for desulfurization of sodium aluminate solutions. • A ZIF-8-derived porous carbon photocatalyst with outstanding stability in sodium aluminate. • Mesoporous structure enhances the photocatalytic performance of the photocatalyst. • Co and C doping improved visible-light conversion efficiency of the photocatalysts. • OH and O 2 − were the main reactive oxygen species in S 2 O 3 2− photodegradation.

Guided by the "trinity" prospecting prediction theory, this paper provides a comprehensive summary of the three core elements of the Jawurah deposit. The findings of the study indicate that the Jawurah deposit represents a typical terrestrial medium-low-temperature magmatic hydrothermal silver-palladium-zinc deposit. The mineralized geological bodies are predominantly composed of Cretaceous diorite porphyry and granitic porphyry, while the principal mineralizing structures are northwest-trending tensional faults. The mineralizing fluids exhibit characteristics of a mixture of magmatic water and atmospheric precipitation. Based on an integrated analysis, a three-dimensional prospecting model of "rock body controlling mineralization, structure guiding mineralization, and alteration indicating mineralization" has been proposed. This model offers robust theoretical support for regional prospecting breakthroughs.

Copper slag (CS), a prominent industrial by-product derived from copper sulphide concentrate smelting, contains valuable copper minerals. Mineralogical analysis revealed 0.56% arsenical copper/chalcopyrite, 1.29% chalcocite, 0.25% cuprite, and 0.24% bornite as the primary copper-bearing phases. Given the rapid depletion of readily exploitable copper resources, CS has emerged as a significant source for copper production. A systematic investigation was conducted to establish optimal operational parameters for classification, grinding, and flotation. This study encompassed diverse scenarios and laboratory tests, with a particular focus on reagent application, including types and consumption rates. The findings demonstrated that Na2S is used to activate copper oxide minerals that are difficult to recover after a period of grinding, increasing the recovery rate of CS from 53.92% to 87.58%, and the two-stage grinding process is beneficial for precise control of the particle size, considering both energy efficiency and mineral recovery rate. Upon conducting a comprehensive investigation into the closed-circuit flotation process for copper recovery from CS under optimal conditions, it was determined that the copper concentrate achieved a grade of 21.24% and a recovery rate of 36.31%. Additionally, the grade of copper in the flotation tailings was diminished to 0.20%. The synchronous enrichment of copper significantly curtails total emissions in pyrometallurgical processing, mitigating pollution from CS flotation tailings. This study offers a scientific foundation for sustainable CS tailing management, promoting resource recovery and reduced environmental impact.