Tin belongs to critical metals for EU mainly for energy technologies (SET-plan) and it occurs practically in all electronic devices. In an effort to save and recover this element from electric and electronic waste (WEEE) the possibility for intensification of tin leaching by use of oxidative agent - ozone was studied in this work. As the WEEE represents an extremely heterogeneous system composed of various kinds of metals and materials, experimental work was first dealing with study of pure tin metal behaviour during ozone assisted leaching. The ozone produced in ozone generator was bubbling continuously during defined time through leaching solution placed in glass reactor. The production of ozone by ozone generator (expressed in grams of O_3 per hour) as well as its solubility in sulphuric acid solutions was measured by iodometric analysis. At the beginning, the influence of sulphuric acid concentration (1 - 3 M) and temperature of solutions (20, 30, 50 °C) on ozone solubility was tested. After that, the extraction of tin (~ 5 x 3 x 1 mm cut pieces of pure metal) during leaching in sulphuric acid continuously saturated with ozone at constant flow was investigated. The influence of acid concentration, time and temperature as well as ozone flow rate on tin extraction was monitored. The extraction values for tin during leaching by use of ozone were always compared with those obtained without ozone action. Results showed that temperature of solution has detrimental effect on ozone solubility. On the contrary, acid concentration in the range of 1 - 3 M H2SO4 has positive effect on ozone solubility. Tin was not extracted after leaching for 2 hours in 1 M H2SO4 without ozone and after 6 hours of leaching in the same media the extraction represented only 2 %. However, after bubbling of ozone through the solution at ozone flow rate 7 g/hr at standard conditions (101 kPa, 20 °C), the extraction after 2 hours was enhanced to 15 % and after 5 hours increased to around 70 %. It was shown, that by presence of ozone during leaching in H2SO4 at standard conditions, it is possible to intensify the leaching process and tin extraction efficiency significantly. The main limiting factor of tin extraction was ozone flow during leaching. The influence of acid concentration on tin extraction was less essential. The solubility of tin species present in the solution and tin saturation during leaching played some role in the leaching process efficiency, too.
展开▼
机译：锡属于欧盟的关键金属，主要用于能量技术（设定计划），其实际上在所有电子设备中发生。为了节省和恢复电动和电子废物（WEEE），在这项工作中研究了通过使用氧化剂 - 臭氧加剧锡浸出的可能性。随着WEEE代表由各种金属和材料组成的极其异质系统，实验工作首先处理臭氧辅助浸出过程中纯锡金属行为的研究。在臭氧发生器中产生的臭氧在定义的时间内连续起动，通过浸入玻璃反应器中的浸出溶液在定义的时间内进行起泡。通过碘分析测量通过臭氧发生器（以克3 /小时表示以克3）的氧化克溶液中的溶解度的产生。在开始时，测试硫酸浓度（1-3M）和溶液（20,30,50℃）对臭氧溶解度的影响。之后，研究了在恒定流动中连续饱和臭氧的硫酸中浸出期间锡（〜5×3×1mm切割纯金属）的溶液。监测酸浓度，时间和温度以及臭氧流速对锡萃取的影响。通过使用臭氧的浸出期间锡的提取值与没有臭氧作用的臭氧进行比较。结果表明，溶液温度对臭氧溶解性有害影响。相反，1-3M H 2 SO 4范围内的酸浓度对臭氧溶解性具有阳性作用。在浸入1MH2SO4中浸出2小时后未提取锡，没有臭氧，在相同介质中浸出6小时后，萃取仅表示2％。然而，在标准条件下通过臭氧的溶液溶液鼓泡臭氧（101kPa，20℃），2小时后提取至15％，5小时后增加至约70％。结果表明，通过在标准条件下在H2SO4中浸出期间臭氧的存在，可以显着加强浸出过程和锡提取效率。锡萃取的主要限制因素在浸出过程中臭氧流动。酸浓度对锡萃取的影响较小。在浸出过程中溶液和锡饱和度存在于溶液中的溶解度也在浸出过程效率中起作用。
展开▼
