- Thesis topic: Separation and Recovery of Indium (In3+) Ions and Tin(Sn2+) from Electrolyte by a Supported Liquid Membrane

- Doi: https://doi.org/10.6840/cycu201900142

- Abstract: 

      In this study, supported-liquid-membrane with-strip dispersion (SLMSD) was used to recover and purify rare-earth metals of indium from the electrolytic waste solution in a two-step process. Indium oxide has been widely used in various types of optoelectronic products in recent years, among which Indium Tin Oxide (ITO) accounts for the highest proportion, and as the amount of manufacturing increases, a large amount of etching waste liquid containing indium is also increasing. More, coupled with the recent fluctuations in the price of rare metal indium, the economic benefits of recycling and purification of indium metal should not be underestimated.
       Based on the results of the full analysis of indium-containing waste liquid, this study used batch extraction experiments, indium tin separation experiments, batch back extraction experiments to obtain the best operating parameters of SLM and perform mold operation.
. The extractant is 0.5M D2EHPA, the oil-water ratio is 15 ml of waste liquid: 13 ml of extractant, oil-water ratio 20 ml extractant/5 ml of stripping agent, and 3N HCl is used as a stripping agent to recover indium ions by supported liquid membrane. The purity of tin ions in the extractant is about 74%, the recovery efficiency of indium ions is 62%, the purity of indium ions is increased from 25% to 71%, the concentration of indium ions is increased from 2700ppm to 7800ppm, and the concentration multiple is 2.89 times. .
     The extraction agent is 0.5M D2EHPA, the oil-water ratio is 20 ml of waste liquid: 10 ml of extractant, oil-water ratio 20 ml extractant/5 ml of stripping agent, and 5N H2SO4 is used as a stripping agent to hold tin ions by supported liquid membrane to increase the purity of indium ions in the extractant, and further recover the indium ions. After the reaction, the purity of indium ions in the extractant is 10%, and the purity and concentration of tin ions in the stripping agent are 98% and 30,000 ppm. However, the large-scale SLM experiment with the same parameters, the results are almost the same with the small scale,the results of small-scale experiments can be used to estimate the economic benefits of the field.
       In the process of purification and recovery of indium ions, t the concentration of tin ions is much higher than Indium ions. Even if the tin ions are first grabbed, the purity of the indium ions in the extractant is only 10%, but the obtained stannous hydroxide and tin-containing solution were used to estimate the economic benefit of the field. It was found that the daily treated water volume was 25 CMD, and the yield of 11,137,375 NT$ was obtained per year.

Keywords:  D2EHPA, SLMSD, Indium, Tin, Extraction, D2EHPA