فهرست نشریات علمی دسترسی آزاد ایران

The accumulation of spent vanadium catalysts from sulfuric acid production poses a serious environmental problem on a global scale. Existing hydrometallurgical methods focus on vanadium extraction, often leaving a solid siliceous residue without qualified application. In this study, a resource-saving technology for the full-cycle synthesis of a granulated catalyst was developed using the solid leaching residue of SVC as a secondary carrier and bentonite as a structural promoter. Sulphuric acid leaching (15% H2SO4, 85 °C, 4 h, and solid-to-liquid ratio 1:4), filtration, washing, and thermal activation were carried out, with a complete material balance established for the key components (V, S, and K). The V2O5 recovery was 85.0%. The secondary carrier was synthesized by extrusion molding using washed siliceous residue (SBET ≈ 15 m2/g) and bentonite (15 wt.%). Statistical significance was assessed using Student’s two-sample t-test for independent samples with n=5 and p=0.95; the normality of the distribution was tested using the Shapiro-Wilk test, and the effect size (Cohen’s d) was calculated. It was found that the addition of 15% (by mass) of activated bentonite to the secondary siliceous residue yields carrier granules with a strength of 62 ± 4 N/granule, which corresponds to ~2.2 MPa at a granule diameter of 6 mm (6.2 MPa was erroneously mentioned) and a developed macroporous structure (Vtotal = 0.36 ± 0.02 cm3/g), ensuring efficient mass transfer. The waste-based synthesized catalyst (8% V2O5) demonstrated an activity of 93.9±0.6% at 485 °C, which is statistically indistinguishable from the performance of the industrial SVD standard (p > 0.05). A closed-loop technology is proposed, allowing up to 85 wt.% of hazardous waste to be returned to the production cycle. A preliminary assessment of economic efficiency indicates a potential reduction in raw material costs of 25-35%, provided that production is scaled up to industrial volumes (>100 tons per year). Resource tests demonstrated stable catalytic activity over 60 h of continuous operation at 485 °C. This duration confirms the absence of rapid degradation of the active phase; however, long-term testing (1,000+ h) is required to assess industrial durability.