Hocheng H, Hong T, Jadhav U
Department of Power Mechanical Engineering, National Tsing Hua University, No. 101, Sec.2, Kuang Fu Rd., 30013, Hsinchu, Taiwan, Republic of China,
Appl Biochem Biotechnol. 2014 May;173(1):193-204. doi: 10.1007/s12010-014-0833-2. Epub 2014 Mar 15.
This study proposes an environment-friendly bioleaching process for recovery of metals from solders. Tin-copper (Sn-Cu), tin-copper-silver (Sn-Cu-Ag), and tin-lead (Sn-Pb) solders were used in the current study. The culture supernatant of Aspergillus niger removed metals faster than the culture supernatant of Acidithiobacillus ferrooxidans. Also, the metal removal by A. niger culture supernatant is faster for Sn-Cu-Ag solder as compared to other solder types. The effect of various process parameters such as shaking speed, temperature, volume of culture supernatant, and increased solder weight on bioleaching of metals was studied. About 99 (±1.75) % metal dissolution was achieved in 60 h, at 200-rpm shaking speed, 30 °C temperature, and by using 100-ml A. niger culture supernatant. An optimum solder weight for bioleaching was found to be 5 g/l. Addition of sodium hydroxide (NaOH) and sodium chloride (NaCl) in the bioleached solution from Sn-Cu-Ag precipitated tin (85 ± 0.35 %) and silver (80 ± 0.08 %), respectively. Passing of hydrogen sulfide (H2S) gas at pH 8.1 selectively precipitated lead (57.18 ± 0.13 %) from the Sn-Pb bioleached solution. The proposed innovative bioleaching process provides an alternative technology for recycling waste solders to conserve resources and protect environment.
本研究提出了一种从焊料中回收金属的环保生物浸出工艺。本研究使用了锡铜（Sn-Cu）、锡铜银（Sn-Cu-Ag）和锡铅（Sn-Pb）焊料。黑曲霉的培养上清液比氧化亚铁硫杆菌的培养上清液去除金属的速度更快。此外，与其他类型的焊料相比，黑曲霉培养上清液对Sn-Cu-Ag焊料的金属去除速度更快。研究了诸如振荡速度、温度、培养上清液体积和增加焊料重量等各种工艺参数对金属生物浸出的影响。在200转/分钟的振荡速度、30℃的温度下，使用100毫升黑曲霉培养上清液，在60小时内实现了约99（±1.75）%的金属溶解。发现生物浸出的最佳焊料重量为5克/升。在来自Sn-Cu-Ag的生物浸出溶液中添加氢氧化钠（NaOH）和氯化钠（NaCl）分别沉淀出锡（85±0.35%）和银（80±0.08%）。在pH值为8.1时通入硫化氢（H2S）气体可从Sn-Pb生物浸出溶液中选择性沉淀出铅（57.18±0.13%）。所提出的创新生物浸出工艺为回收废焊料以节约资源和保护环境提供了一种替代技术。
