SU897899A1 - Method of automatic control of aluminium electrolyzers - Google Patents

Description

one

The invention relates to the production of aluminum by an electrolytic method and can be used to automate this process.

A known method of automatically controlling aluminum electrolysis cells includes measuring the voltage on the electrolyzer, the electrolysis current, the ohmic resistance of the electrolyzer and maintaining the controlled parameter within the specified limits by moving the anode 1.

The disadvantage of this method is in a relatively low productivity of the electrolyzer.

The aim of the invention is to increase the productivity of the electrolyzer.

This goal is achieved in that according to the method, which includes measuring the voltage on the electrolyzer, the electrolysis current, the ohmic resistance of the electrolyzer and maintaining the adjustable paamemeter in

the predetermined limits by moving the anode, once every 20-70 minutes, the alternating components of the voltage on the electrolyzer and the electrolysis current are separated at a frequency below the resonant frequency of the voltage and current measurement circuit and by these variable components of the voltage and current and by the ohmic resistance of the electrolyzer The reactance of the electrolyzer, used as a controlled variable.

The proposed method is based on the following. Straightening scheme and physico-chemical features of the process

Claims (1)

15, the electrolysis of aluminum determines the presence of variable components of the electrolysis current and the voltage on the electrolyzer. For these variable components, the aluminum electrolysis cell represents an impedance, and the capacitance component of this resistance for a given cell design is mainly determined by the interpolar distance. At frequencies below the resonant frequency of the current and voltage measurement loop, the reactive component of the electrolyzer resistance more capacitive than inductive. at these frequencies, the resistance component of the electrolyzer is mainly determined by the value of the interpolar distance. The essence of the method is as follows. Once every 20-70 minutes, alternating components of the voltage on the electrolyzer and the electrolysis current at a frequency of 5 below the resonant frequency of the voltage and current measurement circuit are separated. From these variable voltage and current components and from the ohmic resistance of the cell, the reactance of the cell is calculated. This reactance is taken as an adjustable parameter. With this adjustment, a parameter proportional to the interpolar distance is measured. Other components of the resistance of the electrolyzer do not affect the measurement results. This increases the accuracy of interpolar maintenance (distance p within specified limits and, consequently, increases electrolizeg performance; Ov. F; -;; d. I shows a simplified electric pattern of replacement of the electrolyzer, where the following conditions are accepted: 3 and U - respectively current and voltage; Ry, |. | .-- respectively the ohmic resistances of the contacts of the anode; Electrolyte and cathodes; x, and xj. are respectively inductance & capacitance component of the impedance of the electrolytic cell; E is the electrochemical component right Fig. 2 shows the dependence of the ohmic R, the inductive x, capacitance Z of the resistance X and the complete electrolyzer on the frequency; the electrolyzer and the ohmic resistance of the electrolyzer for 0.1 minutes, the current is monitored by means of a shunt included in the busbar rupture.The voltage is removed from the anodic and cathodic busbars of the electrolyzer. Resistance to resistance is monitored in the usual way by constant current and voltage components. Electric filters are used to extract the variable components of the current and the voltage at a frequency of 0.1 fpgj, where fp83 is the resonant frequency of the current and voltage measurement loop. The selected alternating current and voltage components are rectified. By moving the anode, the reactance x, from the anode is maintained at a predetermined level, determined by the rectified values of the variable components of the current Jr and the voltage U t- and by the ohmic resistance of the electrolytic cell in accordance with the expression D) - R Application pred; - with sioSoBa, the interpolar distance is maintained at a given level with greater accuracy and, as a result, the current output is increased by 0, and also the specific yo-sag of the switchboard is reduced: s: j. Claims of the Invention Method as O1 "(attribute; .O: about ucryninjo vani dji 0; -i -inneebi (alecty; :: iaepos, including measurement -iai: ri:; (enip on electrolyzer S electrolysis current, 0 :. , the resistance of the electrolysis cell and the maintenance of the controlled parameter within the prescribed limits of the anode displacement; so that, in order to increase the productivity of the electrolysers, the variables are separated every 20-70 minutes the components of the voltage on the electrolyzer and the current of electrolysis at a frequency below the resonant frequency of the circuit measuring the voltage and current and these variables By comparing the voltage and current components and the ohmic resistance of the electrolyzer, the reactance of the electrolyzer is calculated, taking as an adjustable parameter. Sources of information taken into account in the examination 1. Foundations of metallurgy, Vol. Y1, M., Metallurgists, 1973, p. 31-A38.