Device and method for measuring local counter electromotive force of industrial aluminum electrolytic cell

Abstract

The invention discloses a device and a method for measuring the local counter electromotive force of an industrial aluminum electrolytic cell. The device comprises a cell interior region side part isolation frame, a melt body interior reference electrode, an anode guide rod voltage probe, high-temperature-resistant copper wires, a high-frequency digital oscilloscope and an interface module. According to the device and the method, the counter electromotive force is measured based on an outage method, local electrolytes of the replaced anode are insulated from the periphery by utilizing a principle that a replaced anode must be powered off when the electrolytic cell is subjected to anode changing, and the counter electromotive force of the local region is accurately measured at the moment when the replaced anode is powered off so as to obtain the counter electromotive force of the local region in the cell can be obtained. The device and the method have the advantages that the counter electromotive force of the local region of the electrolytic cell can be safely and rapidly measured, meanwhile, each cell is measured once every day by utilizing the anode changing period, normal production of the electrolytic cell cannot be influenced, the algorithm of a control system can be calibrated through the counter electromotive force, and therefore the important practical value can be achieved.

Description

technical field [0001] The invention relates to the technical field of aluminum electrolysis, in particular to a device and method for measuring local counter electromotive force of an industrial aluminum electrolytic cell. Background technique [0002] The industrial aluminum electrolysis process is a molten salt electrolysis process. After the anode of the electrolytic cell is fed with direct current, the electrolytic reaction is carried out in the cell to obtain metal aluminum. According to the electrochemical theory, when direct current passes through the molten salt, electrolysis starts only when the applied voltage reaches a certain value, and to maintain the progress of electrolysis, the applied voltage cannot be lower than the minimum voltage value, this voltage is called theoretical decomposition Voltage. The theoretical decomposition voltage can be accurately calculated from thermodynamic data, that is, it can be calculated through the activity value of each subst...

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Problems solved by technology

Zhang Mingjie and Qiu Zhuxian from Northeastern University have made many explorations in this field, but it is still difficult to find an industrially applicable back EMF measurement distribution

For the above five methods, first of all, during the normal production of the electrolytic cell, it is impossible to suddenly cut off the power, so the full series power-off method is not suitable for measuring the back electromotive force of the industrial aluminum electrolytic cell; for the scanning reference method, due to the overvoltage in the cell If it is less than 80mV, the ohmic pressure drop of the system cannot be eliminated by using a Lukin capillary similar to that commonly used in aqueous solution when measuring the polarization curve. The accurate deduction or compensation of the ohmic pressure drop has always been an urgent problem in the electrochemical research of high-temperature molten salts. A key technical problem, so the measurement error is huge; for the ripple method, it is difficult to measure due to the large number of industrial electrolytic cells, high total voltage, and small number of AC harmonics, and the cell resistance is small, and the signal generator is large, etc. It is difficult to measure successfully due to some reasons; the statistical regression method is limited by the amount of data, resulting in low precision; other methods have similar problems

[0008] It can be seen that there is still a lack of a more economical and effective back electromotive force measurement method for industrial aluminum electrolysis cells. The back electromotive force in the aluminum electrolysis control system is mostly an artificially assumed value. large deviations from management

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