排序方式: 共有24条查询结果,搜索用时 109 毫秒
21.
Zinc solder dross containing 14.8% Sn, 16.3% Pb, 0.41% Al and 64.5% Zn was leached with 3% H2SO4 at 45°C for 1 h. Zinc and aluminum went into solution, whereas lead and tin remained with the residue. Aluminum was selectively precipitated as calcium aluminum carbonate by treating the sulphate leachate with limestone at pH 4.8. Zinc sulphate solution was either evaporated to obtain zinc sulphate crystals or precipitated as basic zinc carbonate at pH 6.8. The undissolved lead and tin were leached with 5 M hot hydrochloric acid. The major part of lead chloride ( 73%) was separated by cooling the leached products down to room temperature. From the soluble fraction, tin was recovered as hydrated tin oxide by alkylation with caustic soda at pH 2.4, while the remaining lead was separated at pH 8.5 as lead hydroxide. A process flowsheet had been suggested which involved two-stage hydrometallurgical treatment. Parameters affecting the recovery efficiency of the suggested method such as temperature, time, pH and acid: solid stoichiometric ratio were investigated. Results obtained revealed that the optimum leaching conditions were achieved by using 20 ml of 3% H2SO4 acid/g dross for 1 h at 45°C. Recovery efficiency of the metal salts was 99.1, 99.4, 99.6 and 99.5% for Zn, Al, Pb and Sn respectively. Recovery efficiency was related to the solubility of the concerned salts under the given experimental conditions. 相似文献
22.
Abubakar Sadiq Aliyu Timothy Alexander Mousseau Ahmad Termizi Ramli Yakubu Aliyu Bununu 《Ambio》2015,44(8):778-787
The tin mining activities in the suburbs of Jos, Plateau State, Nigeria, have resulted in technical enhancement of the natural background radiation as well as higher activity concentrations of primordial radionuclides in the topsoil of mining sites and their environs. Several studies have considered the radiological human health risks of the mining activity; however, to our knowledge no documented study has investigated the radiological impacts on biota. Hence, an attempt is made to assess potential hazards using published data from the literature and the ERICA Tool. This paper considers the effects of mining and milling on terrestrial organisms like shrubs, large mammals, small burrowing mammals, birds (duck), arthropods (earth worm), grasses, and herbs. The dose rates and risk quotients to these organisms are computed using conservative values for activity concentrations of natural radionuclides reported in Bitsichi and Bukuru mining areas. The results suggest that grasses, herbs, lichens, bryophytes and shrubs receive total dose rates that are of potential concern. The effects of dose rates to specific indicator species of interest are highlighted and discussed. We conclude that further investigation and proper regulations should be set in place in order to reduce the risk posed by the tin mining activity on biota. This paper also presents a brief overview of the impact of mineral mining on biota based on documented literature for other countries. 相似文献
23.
碱熔法消解-原子荧光法测定土壤中的锡 总被引:1,自引:0,他引:1
利用碱熔法消解土样、氢化物发生-原子荧光法测定土壤中的锡。选择最佳的仪器条件,经过碱熔法消解后,在体积分数为5%的盐酸介质中,锡荧光强度与其质量浓度在0~200μg/L成线性关系。方法的相对标准偏差为2.2~7.2%,实际样品加标回收率为90%~95%。此方法操作简便,灵敏度高,检出限低,适用于土壤中微量锡的测定。 相似文献
24.
原子荧光光谱法测定水中低含量锡 总被引:5,自引:0,他引:5
李飞 《环境监测管理与技术》2005,17(4):28-28
采用原子荧光光谱法测定水中锡,结果表明,方法检测限为0.14μg/L,在0、0μg/L~100μg/L范围内线性良好。不同浓度标准溶液测定的相对误差≤2.0%,实际样品测定的加标回收率在90.0%~109%之间,相对标准差≤6.1%,准确度和精密度均较好。 相似文献