A Method for Establishing Alumina Concentration Equilibrium in Complex Electrolyte System

Abstract

The invention discloses a method for establishing alumina density balance under a complicated electrolyte system. The method comprises the following steps of: firstly, presetting aluminum reduction cell voltage U, an electrolyte temperature T, an electrolyte level L1 and an aluminum level L2; secondly, setting up initial voltage U0 to be equal to U plus u and an initial aluminum level L20 to be equal to L2 plus l2 cm; thirdly, gradually increasing the molecular ratio of NaF / AlF3 to 2.60-2.75 by the means of adjusting the feeding amount of NaF in an electrolytic cell, and then reducing the voltage U, the temperature T and the aluminum level L2 to the preset value; and fourthly, setting final voltage U1 which is obtained by subtracting umv by U after the effects of energy balance and material balance are obtained under the preset value. The method can be used for controlling the alumina density in a more scientific and more efficient way, and for better establishing an alumina density balanced relationship according to the condition of an electrolytic cell. The alumina density can be kept around 2.6% at average, and the fluctuation range of the alumina density is from about 1.5% to about 3.5%.

Description

technical field [0001] The invention belongs to the technical field of electrolytic aluminum, and in particular relates to a method for establishing concentration balance of alumina in a complex electrolyte system. Background technique [0002] In the production practice of large-scale prebaked aluminum electrolytic cells, the quality of alumina concentration control technology and the establishment of balance are very important for stabilizing cell conditions, improving current efficiency and reducing energy consumption. [0003] At present, in a large number of domestic production practices, due to the influence of various related factors such as existing technical conditions, manual operation quality, raw and auxiliary materials quality, and auxiliary processes, the composition of the electrolyte system is complex and diverse, and the concentration ratio between different components is not easy. Control, especially the concentration of alumina is difficult to control to t...

AI Technical Summary

Problems solved by technology

[0003] At present, in a large number of domestic production practices, due to the influence of various related factors such as existing technical conditions, manual operation quality, raw and auxiliary materials quality, and auxiliary processes, the composition of the electrolyte system is complex and diverse, and the concentration ratio between different components is not easy. Control, especially the concentration of alumina is difficult to control to the best state, the average concentration of alumina reaches about 3.5%, and the fluctuation is large, the performance of electrolyte fluidity, conductivity and dissolved alumina is poor, and the concentration balance is difficult to establish

Therefore, it seriously affects the improvement of the current efficiency of the aluminum electrolytic cell and the reduction of energy consumption, and also restricts the further development of aluminum electrolytic production to a large extent.

[0004] Under the current situation that the automation degree of domestic aluminum electrolysis production is not high, the quality of manual operation will have a great impact on the control of alumina concentration and the establishment of concentration balance, which is mainly reflected in the following two aspects: 1) anode exchange; current situation: ① The quality of pole change is poor, and the qualified rate of new poles within 16 hours is ≤90%; ② The operation time of pole change is too long (it takes about 28 minutes to change an anode) and the operation is not standardized, which greatly interferes with the electrolytic cell; 2) The feeding point is open Porosity; status quo: The opening rate of the feeding point is ≤80%, which seriously affects the supply of materials to the electrolytic cell

Images