Extraction of cobalt, copper, and silver from scrap saw-blade segments using nitric acid solutions (0.1–0.4 M, 20–60°C) were investigated using response surface methodology. Extraction of cobalt and iron was more extensive than copper and silver, i.e., 35.7–96.2% Co and 72.6–100% Fe versus 8.50–35.4% Cu and 8.11–22.5% Ag. Statistical analysis of the experimental data has shown that increasing the acid concentration or temperature enhances the rate and extent of leaching of metals. Under suitable conditions, almost complete leaching of cobalt (99.9%), as well as high extractions of copper (95.9%) and silver (94.9%), were achieved. The activation energy, calculated to be 40.3 kJ/mol, indicates that nitric acid leaching of these metals occurs as a chemically controlled reaction. These findings have demonstrated that nitric acid as an effective oxidant/leaching agent could be suitably used for the extraction of cobalt, copper, and silver from scrap segments.

使用响应表面方法研究了使用硝酸溶液（0.1–0.4 M，20–60°C）从废锯片段中提取钴，铜和银的方法。钴和铁的萃取比铜和银的萃取更广泛，即35.7–96.2％的钴和72.6–100％的铁与8.50–35.4％的铜和8.11–22.5％的银相比。实验数据的统计分析表明，提高酸浓度或温度可提高金属浸出的速度和程度。在合适的条件下，可以实现钴的几乎完全浸出（99.9％），以及铜（95.9％）和银（94.9％）的高浸出率。计算出的活化能为40.3 kJ / mol，表明这些金属的硝酸浸出是化学控制的反应。