碳酸钠和硫酸钠对铝酸钠溶液结构的影响

王丹琴，李小斌，周秋生，刘桂华，彭志宏

(中南大学 冶金科学与工程学院，湖南 长沙，410083)

摘 要：利用红外光谱，研究碳酸钠和硫酸钠对铝酸钠溶液结构的影响。同时，研究当有碳酸钠和硫酸钠存在时，铝酸钠溶液的结构变化对其物理化学性质和分解过程的影响。研究结果表明：碳酸钠和硫酸钠均会改变铝酸钠溶液的结构，随着碳酸钠和硫酸钠浓度的增加，铝酸钠溶液中四面体离子Al(OH)₄^-明显减少，低波数段Al-O-Al结构的Al₂O(OH)₆^2-离子明显增多。同时，加入碳酸钠和硫酸钠后，铝酸钠溶液结构上的变化将导致铝酸钠溶液黏度升高，电导率下降，并对晶种分解过程产生抑制作用。由此说明，铝酸钠溶液的结构变化对其物理化学性质及分解过程有很大影响。即铝酸钠溶液中聚合离子增多，不利于铝酸钠溶液的晶种分解。

关键词：铝酸钠溶液；结构；电导率；黏度；碳酸钠；硫酸钠

Effect of sodium carbonate and sodium sulfate on structure of sodium aluminate solution

WANG Dan-qin, LI Xiao-bin, ZHOU Qiu-sheng, LIU Gui-hua, PENG Zhi-hong

(School of Metallurgical Science and Engineering, Central South University, Changsha 410083 China)

Abstract:Combining with the infrared spectroscopy (IR) analysis, the effects of Na₂CO₃ and Na₂SO₄ on the structure of sodium aluminate solutions were investigated. In addition, the effects of structural changes on the physicochemical properties of sodium aluminate solutions with Na₂CO₃ and Na₂SO₄ and precipitation process of gibbsite from sodium aluminate solutions were also investigated. The results show that the Na₂CO₃ and Na₂SO₄ can change the ion structure of the aluminate solution, and the concentration of Al(OH)₄^- declines remarkably, while the concentration of Al₂O(OH)₆^2- increases obviously according to the FTIR analyses when the concentrations of Na₂CO₃ and Na₂SO₄ increase. Besides, the viscosity of sodium aluminate solution increases, the electric conductivity decreases and the gibbsite precipitation is inhibited with adding Na₂CO₃ and Na₂SO₄. Consequently, the structural changes of aluminate solution have important influence the physicochemical properties and precipitation process of sodium aluminate solution. And elevated concentration of polymeric aluminate anions is harmful to the precipitation process of gibbsite from sodium aluminate solution.

Key words:aluminate solution; structure; electric conductivity; viscosity; sodium carbonate; sodium sulfate