Preparation and characterization of lithium adsorbent

• Main Authors: Fei-Peng Yu, 余飛鵬
• Other Authors: Min-Shin Tsai
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/56047051496551261796

碩士 === 國立成功大學 === 資源工程學系碩博士班 === 90 === Abstract With technological development, people’s demands of material become higher and the supply of mineral and energy are respected by human as well. The demanding of lithium mental has been increases a lot under the popularity of communication products. Such requirements in 1990 is 300 thousands and 90 million in 1999. There are a plenty of lithium compound in seawater. If we can successfully and effectively extract lithium from seawater, seawater would become an important way to gain lithium. λ-MnO2 which treat with acid from LiMn2O4 can uptake lithium. As a result our study observes the conditions of synthesis, acid treatment by (NH4)2S2O8, and adsorption coefficients. Based on the experiment, the LiMn2O4 sample prepared by mixing Li2CO3 and MnCO3 with the mol ratio between 0.5~0.6 above 600℃ for 4 hours and the increasing rate 5℃/min can produce pure LiMn2O4. It’s specific area is 0.06m2/g and particle size is 22.64 A。. We obtain manganese oxides with temperature above 600℃ and mole ratio below 0.5. When mole ratio is above 0.6 we will obtain Li2MnO3. A great amount of manganese oxide will remain if the temperature is below 600℃and the time of duration is less than 4 hours. MnCO3 decomposing will leads Li2CO3 to decompose at lower temperature in advance. LiMn2O4 which is heated at 700℃ with mole ratio 0.5 for 4 hours and 0.5M (NH4)2S2O8 at 70℃ for 40 minutes will produce optimum adsorbent. Each gram of adsorbent can uptake 31.5mg lithium. The amount of uptaked lithium are the same as that which is treated with HCl and (NH4)2S2O8.However, using HCl results in a relatively high Mn dissolution, but using (NH4)2S2O8 doesn’t obtain. We get less amount of adsorbent after using HCl. Besides we can observe that peak is shifting slightly before and after acid treatment. The enthalpy for the reaction is -10.15Kcal/mol, which belongs to chemisorption. The amount of lithium absorption wouldn’t be affected by sodium ion.