SU605867A1 - Method of monitoring condition of aluminium electrolyzer anode foot - Google Patents

Description

The proposal is based on the results of research carried out on a semi-industrial type electrolyzer, about the effect of gas released from under the anode, uneven ground, current density, temperature and electrolyte composition on the operating voltage fluctuations.

The essence of the phenomena occurring in the presence of irregularities on the anode base is that the current density on the protrusions is greater than on the valleys.

The increased gas production on the protrusions increases the fluctuations in the resistance of the interpolar gap and the operating voltage of the electrolyzer. When the voltage of the anode effects is less than optimal for this design of the electrolyzer, the effect of unevenness of the sole on the operating voltage fluctuations becomes decisive. In this case, the localization of gas evolution in the peripheral zones of the anode base creates more oscillations of the operating voltage on the C-7 electrolyzers.

at different conditions of the anode base

high fluctuations in operating voltage than in central ones.

This is confirmed by the result of the 1MI registration of the operating voltage fluctuations on industrial-type electrolyzers.

It was found that, depending on the design of the electrolyzer and the nature of the unevenness of the anode base, the oscillations of the operating voltage caused by the fluctuations of resistance of the interpolar gap under the influence of the flow of gas bubbles are in the range of 0.5-4 Hz, 1-100 mV.

For electrolyzers with a 160 kA upper current lead, the table shows the most frequently observed values of the frequency and amplitude of the operating voltage fluctuations during deep and shallow anode irregularities that are not in contact with the cathode.

.Table continuation

1.73

1.71

1.75

1.6

1.63

1.62 From the table it can be seen that with and voltage effects below 35 V (the optimal voltage of anode effects on electrolysers of this type is 35-45 V) in the IMM irregularities correspond to the operating voltage fluctuation ({) in the range of 1.2-1 , 8 Hz, deep - 1.5-3.0 Hz, Unevenness m, located on the periphery of the anode, correspond to oscillations. (A) with an amplitude of 8-15 to 30 mN, centered 1-8 mV. Thus, certain values of the frequency range of the anode base correspond to certain values of the frequency range and amplitude of oscillations of the operating voltage: 1.2–1.5 Hz 1–7 mV — minor irregularities in the central zones of the anode base 1.5–1.8 HZ; 1.8 mV - deep irregularities in the central zones of the anode base ;. 1.5-1.8 Hz; 8-30 mV - small irregularities in the peripheral zones of the anode; 1.8-3 Hz; 8-30 mV - deep irregularities in the peripheral zones of the anode. Automated monitoring of the state of the anode base can be implemented by a recorder of low-frequency electrical voltage oscillations, suitable for recording oscillations with a frequency of up to several hertz and an amplitude of up to several hundred millivolts, and automatic control using, for example, an electronic computer included in the structure of the automated system. controlling the process of electrolysis of aluminum by connecting them for a certain time to the anode-cathode section of each controlled electrolyzer. The selection of the oscillation range. The frequency of 0.5-4.0 Hz can be carried out when used as a register15 13

Claims (3)

1.84 1.84 1.85 20 low-frequency oscillations of an electric voltage, for example: a standard self-writing millivoltmeter of the type H-39 at a speed of its tape-drawing mechanism of 5400 mm per hour. To offset the clamp on the chart tape, a compensating voltage from an unwanted DC source is used. The drawing shows a diagram tape of the device with the registration of the oscillations of the operating voltage of one of the controlled electrolyzers. Its processing for the purpose of monitoring the state of the anode base can be performed directly by the operator or using a computing device. The proposed method of controlling the state of the anode base provides the following procedure. 1. Connecting the recorder of low-frequency oscillations of the electric voltage in the range of 0.5-4 Hz and 1-100 mV to the anode-cathode section of the working electrolyzer. The time T of the registration of the operating voltage fluctuations is chosen preferably from 10 to 20 seconds, based on the requirements and speed of monitoring and accuracy of determining the average frequency i and the average amplitude A of the operating voltage fluctuations. 2.Calculation of average values of the frequency and amplitude of oscillations of the operating voltage according to the formulas gden - the number of periods of oscillations of the operating voltage of the electrolyzer during the registration T, s. ON is the total value of the amplitude A of the operating voltage fluctuations during the registration time T, s. 3. Obtaining information about the voltage of the anode effect (11 d) of the previous recording of operating voltage fluctuations, and comparing the computational values of A and f at V az. sleep characteristic for each variety of unevenness of the sole anol. Example. On the electrolyzer No. 73, 35 periods of oscillation of the operating voltage with an amplitude from 1 to 20 mV and an integral value of 350 mV were recorded by the upper current lead of 160 kA for 20 s. The calculated value is 5 350,, 75g4). Estimation of irregularities, anode base: deep irregularities on the periphery of the anode that are not in contact with the cathode hot turn Claims The method of monitoring the state of the anode base of the electrolyzer to produce aluminum in amplitude and frequency of the operating voltage with obtaining data regulating the process of electrolysis, accompanied by anodic effects, characterized in that, in order to expand the information, improve the accuracy and speed of control, anodic effects and the electrolyte temperature and when the anodic effects voltage is below the optimum for this type of electrolyzer and the character of irregularities on the anode base according to the ratio between the amplitude of oscillations of the operating voltage IflOO mV and a frequency of 0.5–4 Hz, reduced to a constant electrolyte temperature. Sources of information taken into account in the examination: 1. Application No. 1971194 / 22-1, C 25 C 3/20, 1973, according to which the decision to issue an author's certificate was made.