低温碱性熔炼分离提取废弃电路板粉末中两性金属

Separation and extraction of amphoteric metals from waste printed circuit board powders by low-temperature alkaline smelting

模拟废弃电路板破碎、分选后得到的多金属富集粉末,通过单因素实验和正交试验,采用低温碱性熔炼研究熔炼温度、熔炼时间和盐料质量比对其中有价金属分离提取率的影响.结果表明,最佳条件为熔炼温度400℃,熔炼时间1.5h,盐料质量比3.5,其中盐料质量比对两性金属提取率影响最显著.在最佳条件下,两性金属提取率为Sn 83.6%、Al 92.7%、Zn80.9%及Sb 34.5%,以可溶盐形式富集在浸出液中,铜等其他成分则于渣中富集,有效实现了两性金属与其他金属的分离.

Multi-component metal powders were prepared by imitating the crushed metal enrichment originated from waste printed circuit boards. The effects of smelting temperature, smelting time and NaNO3-NaOH/powder mass ratio on the extracting ratios of amphoteric metals during low-temperature alkaline smelting were investigated through single-factor experiments and orthogonal tests. It is found that the mass ratio of NaNO3-NaOH to crushed metal enrichment has the most significant effect on the extracting ratios of amphoteric metals. The optimum conditions were obtained as the smelting temperature of 400℃, the smelting time of 1. 5 h and the mass ratio of NaNO3-NaOH to crushed metal enrichment of 3. 5. Under the optimum conditions, the extracting ratios of amphoteric metals are as the following：Sn 83. 6%, Al 92. 7%, Zn 80. 9%, and Sb 34. 5%. Amphoteric metals are converted to sodium salts, dissolving in the leaching process, while other components, such as copper and precious metals, are enriched in the residue. In this novel process, amphoteric metals are separated with other metals efficiently.