Electrolytes for large-sized prebaked cell for aluminum-reduction

Abstract

The invention discloses an electrolyte for large-scale pre-curing positive aluminum electrolyser, which is characterized by the following: allocating 38%-16% AlF, 2. 0%-4. 0% LiF, 22. 0%-3. 0% CaF, 21. 0%-2. 0% MgF (rear two parties as natural cumulate) and surplus as Na3AlF6; using single additive; decreasing primary crystal temperature of electrolyte; contenting for the goal of electrolysis handling temperature depression; possessing higher conductivity under the operating temperature; decreasing internal heat between tank pole. This invention can make full use our superiority, which can intensify current by 10%-30%.

Description

technical field [0001] The invention relates to an electrolyte for a large prebaked anode aluminum electrolytic cell, relating to an electrolyte for aluminum electrolysis, in particular to an electrolyte for a large prebaked anode aluminum electrolytic cell. Background technique [0002] my country's aluminum industry independently developed a 280kA large-scale prebaked anode aluminum electrolytic cell (hereinafter referred to as a large cell) in the national large-scale aluminum industry test base in the mid-1990s. After that, a series of 280--350kA large-scale cells were successively designed and built in China. Modern aluminum enterprises, but with the continuous expansion of the capacity of the electrolytic cell or the strengthening of the current, the heat dissipation area per unit ampere of the electrolytic cell, that is, the specific surface area of ​​the electricity, gradually decreases. Internal leakage furnace, while increasing the horizontal current in the tank, res...

AI Technical Summary

Problems solved by technology

Experimental studies have shown that although low-temperature, low-molecular-ratio electrolytes have the advantages of lowering the primary crystal temperature of the electrolyte and significantly improving the current efficiency of aluminum electrolysis, their disadvantages are that the conductivity of the electrolyte melt is reduced, and the solubility and dissolution rate of alumina are reduced. etc. In addition, the stability and thermal stability of the low molecular ratio electrolyte components are greatly reduced, and precipitation at the bottom of the tank is easy to occur, and there is no furnace side on the side, which makes it difficult for the electrolytic cell to operate at low temperature and low molecular ratio to achieve ideal current efficiency.

In addition, CaF in the electrolyte 2 , MgF 2 Although the additives can also reduce the electrolysis temperature and improve the current efficiency, both of them will reduce the conductivity of the electrolyte melt

At present, with the continuous expansion of the capacity of the electrolytic cell, the specific surface area of ​​the large cell is gradually reduced, and the low molecular ratio electrolyte and CaF 2 , MgF 2 The application of additives on large tanks leads to the increase of excess heat between the tank electrodes due to its low electrical conductivity, which leads to many of the above problems