(1. 西安建筑科技大學 冶金工程學院，西安 710055；
2. 中南大學 冶金與環(huán)境學院，長沙 410083；
3. 青海西部水電有限公司，海東 810800)
摘 要: 采用熱分析法研究K3AlF6、LiF和AlF3等含量對鋁電解質Na3AlF6-K3AlF6-AlF3-LiF- CaF2-MgF2-Al2O3熔鹽初晶溫度的影響，分析熔鹽組成對初晶溫度的影響機制。結果表明：含Li熔鹽初晶溫度隨K3AlF6含量的增加而降低，當熔鹽中LiF含量分別為0和4%(質量分數)時，隨著熔鹽中K3AlF6含量從3%增加至12%，熔鹽初晶溫度分別降低27.4 ℃和21.2 ℃；LiF對含K電解質熔鹽初晶溫度有降低作用，當熔鹽中K3AlF6含量分別為0和6%，隨著熔鹽中LiF含量從0增加到4%，熔鹽的初晶溫度分別降低31.2 ℃和27 ℃；AlF3對Li、K共存復雜電解質熔鹽初晶溫度有降低作用，當熔鹽中LiF含量為1%、K3AlF6含量為9%時，熔鹽中AlF3含量每增加1%，熔鹽的初晶溫度將降低6.3 ℃；而當熔鹽不含Li、K時，熔鹽中AlF3的含量每增加1%，可引起熔鹽初晶溫度的降低值為7.6 ℃。復雜電解質熔鹽中鋰鹽和鉀鹽分別以Li2NaAlF6和K2NaAlF6形式存在，其在熔鹽中含量是影響熔鹽初晶溫度的主要原因。
關鍵字: 鋁電解；復雜電解質；鉀冰晶石；初晶溫度；鋰鹽
（1. School of Metallurgical Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
3. Qinghai Western Hydropower Company Limited, Haidong 810800, China）
Abstract:The thermal analysis was applied to study the impact of K3AlF6, LiF and AlF3 on the liquidus temperature of Na3AlF6-K3AlF6-AlF3-LiF-CaF2-MgF2-Al2O3 electrolyte molten melts, and the influence mechanism of the molten melts composition to the liquidus temperature was also investigated. The results show that the liquidus temperature of Li-containing molten melts decreases with the increase of K3AlF6 content, and when the contents of LiF in the melts are 0 and 4% respectively, with the increase of K3AlF6 content from 3% to 12%, the liquidus temperature of molten melts decreases by 27.4 ℃ and 21.2 ℃, respectively. LiF has the effect to reduce the liquidus temperature of K-containing molten melts. When K3AlF6 content of melts is 0 and 6%, with the increase of LiF content from 0 to 4%, the liquidus temperature of molten melts decreases by 31.2 ℃ and 27 ℃. AlF3 has the minus effect on the liquidus temperature of Li-K-containing complex molten melts, when the content of LiF in the melts is 1% and K3AlF6 content is 9%, the liquidus temperature of melts will decrease 6.3 ℃ with every 1% addition of AlF3. While, when the melts don’t contain Li and K, the drop of the liquidus temperature with every 1% addition of AlF3 is 7.6 ℃. Li and K in the complex electrolyte melts exist in the form of Li2NaAlF6 and K2NaAlF6, respectively, and its content in the melts is one of the main reason affecting the liquidus temperature of the molten melts.
Key words: aluminum electrolysis; complex electrolyte; potassium cryolite; liquidus temperature; lithium salts
