中国有色金属学报
ZHONGGUO YOUSEJINSHU XUEBAO
| 第18卷 第11期 总第116期 2008年11月 |
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文章编号：1004-0609(2008)11-2118-09
油酸对铝酸钠溶液分解过程的影响及在产物表面的相互作用行为
吴争平，尹周澜，陈启元，曾纪术，李 洁
(中南大学 化学化工学院，长沙 410083)
摘 要: 研究添加油酸杂质时，铝酸钠溶液分解过程中分解率、氢氧化铝产品的形貌和粒度的分布变化规律；计算以各种不同方式位于氢氧化铝(gibbsite)的(001)和(100)面时油酸分子的总能量和电子结构，并分析各体系的平衡形态及生长习性。结果表明：油酸对铝酸钠溶液的种分过程产生比较明显的抑制作用，油酸的添加量越大，抑制作用越明显；添加1×10−5 mol/L油酸时可促进附聚，添加1×10−4 mol/L油酸时抑制附聚。计算结果表明：油酸接近氢氧化铝(gibbsite)(001)和(100)表面时，体系总能量升高，说明油酸的存在可降低体系的稳定性；油酸在氢氧化铝(gibbsite)(001)和(100)表面上时，油酸分子呈“卧”式时，长大后晶粒体积大于无杂质存在的情况，而油酸分子呈“立”式时，长大后体积小于无杂质时晶粒的体积。理论计算说明油酸的存在会促进或抑制晶体长大的实验结果，从微观层次揭示油酸对氢氧化铝结晶行为影响的实验规律。
关键字: 铝酸钠溶液；油酸；产物表面
Effect of oleic acid on process of precipitation of sodium aluminate solution and interaction mechanism of oleic acid on surface of production Al(OH)3
WU Zheng-ping, YIN Zhou-lan, CHEN Qi-yuan, ZENG Ji-shu, LI Jie
（School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:The change rules of precipitation ratio, microstructure and particle size and the effect of oleic acid on the seed precipitation of sodium aluminate solution were investigated. According to these experimental results, the total energy and electronic structure of oleic acid locating on gibbsite (001) and face (100) with different modes were calculated, and the equilibrium and growth morphology of the systems were analyzed. The experimental results indicate that oleic acid has inhibitory effect on the precipitation, and the inhibitory effect is more obvious with increasing addition of oleic acid. Specially, oleic acid of 1×10−5 mol/L would facilitate the agglomeration of gibbsite, oleic acid of 1×10−4 mol/L would inhibit the agglomeration of gibbsite. Calculation results indicate that the total energy increases when oleic acid is on the surfaces of (001) and (100) of gibbsite respectively. This can explain that the stability of systems decrease when there is some oleic acid on the surface of gibbsite. The calculation results of equilibrium morphology and growth habit show that the volume of growth crystal is larger when some oleic acids with “horizontal” mode exist on the surfaces (001) and (100) of gibbsite. On the contrary, the volume is smaller when there is some oleic acid with “vertical” mode. Theoretical calculations show the correlative experimental facts and unveil the effect of oleic acid on the crystalline of gibbsite at microcosmic level.
Key words: sodium aluminate; oleic acid; production surface
