白钨矿的合成、表面溶解及对药剂吸附性能研究

Study on Synthesis and Surface Solubility of Scheelite and Its Agent Adsorption

采用化学共沉淀法,通过调节反应物浓度和反应温度合成了具有不同结构和微观形貌的白钨矿。采用X射线衍射(XRD)和扫描电子显微镜(SEM)等对白钨矿进行了结构和微观形貌表征。对不同形貌和结构的白钨矿进行了溶解试验和表面电位测试,考察了反应物浓度和反应温度对油酸钠和十二胺在白钨矿表面吸附的影响。结果表明,随着反应物浓度的增加,白钨矿颗粒尺寸减小;反应温度升高,白钨矿的结晶度增大,溶解性降低,其形貌也发生相应变化;白钨矿在水溶液中Ca^(2+)和WO_4^(2-)离子呈现出不一致的溶解行为,是由于白钨矿与水溶液中的阴离子发生了离子交换所致。此外,油酸钠和十二胺在白钨矿表面的吸附特性分别符合Langmuir和Freundlich吸附模型。

Different crystal structures and morphologies scheelite were prepared by adjusting the reaction concentration and temperature using chemical （precipitation） method. Morphology and structure were characterized by XRD and SEM. Dissolution and surface potential of scheelite were tested, the effects of reaction concentration and temperature on sodium oleate and laurylamine adsorbtion on scheelite surface were investigated. The results show that with the increasing of the reactants concentration, the particle size of scheelite decreases, with the reaction temperature increased, the crystallinity of scheelite increase, morphology occur change, solubility decrease. In aqueous solution, the dissolution of tungsten and calcium was incongruous with respect to the lattice ions, Anion-exchange type reaction between these anions in solution and the tungstate ions of the crystal lattice is postulated to explain this behaviour. The results also show that, Langmuir and Freundlich adsorption isotherm can be used to describe the scheelite adsorption of sodium oleate and laurylamine.