Measuring device and method for height of melt of aluminum electrolytic cell and pressure drop of furnace bottom

Abstract

The invention discloses a measuring device and method for the height of melt of an aluminum electrolytic cell and pressure drop of the furnace bottom. The measuring method comprises the steps of proposing derivation processing on potential data based on the huge difference among the specific resistance of air, the specific resistance of aluminum liquid and the specific resistance of electrolyte; determining an air-electrolyte interface and an electrolyte-aluminum liquid interface by analyzing a potential-displacement phi (s) curve and a potential change rate-displacement phi' (s) curve, and further calculating the height of the melt and the pressure drop of the furnace bottom. By means of the measuring device and method for the height of the melt of the aluminum electrolytic cell and pressure drop of the furnace bottom, automatic, efficient and accurate measurement of the height of the melt of the aluminum electrolytic cell and pressure drop of the furnace bottom is achieved, the automation degree is improved, the labor amount of workers is reduced, a process parameter detection result can serve as a control signal source of a cell control machine to be directly fed back to a control system to improve the control level of the cell control machine over the electrolytic cell.

Description

technical field [0001] The invention relates to the technical field of aluminum electrolysis, in particular to a device and method for measuring the melt height and furnace bottom pressure drop of an aluminum electrolytic tank. Background technique [0002] In the traditional Hall-Heroult method aluminum electrolysis production process, production process parameters such as electrolyte height, aluminum liquid height and furnace bottom pressure drop are very important to maintain the normal production of the electrolytic cell. Maintaining a certain electrolyte height in the tank is conducive to the dissolution of alumina and the stability of the heat in the tank. The height of molten aluminum determines the amount of aluminum output. An appropriate height of molten aluminum is not only beneficial to adjust the heat balance in the tank, but also helps to regulate the furnace and improve the stability of the tank, reduce the loss of aluminum dissolution, and improve the current...

AI Technical Summary

Problems solved by technology

For example, the device for measuring the melt height of an aluminum electrolytic cell disclosed in U.S. Patent No. 6,065,867, in order to solve the problems that the electrode guide rod is easy to stick to the electrolyte in practical applications, a sheath rod structure was carried out in the design of the electrode guide rod member. However, in In practical application, when the electrode guide rod rises and resets, part of the electrolyte enters the gap between the jacket rod and the electrode guide rod, which will cause the electrode guide rod to be stuck and cannot work normally.

Domestic devices for measuring the melt height of aluminum electrolytic cells can be roughly divided into non-automated and automated types, both of which have problems such as the electrode guide rod material is easy to adhere to the electrolyte and the sensitivity is reduced or even fails, requiring manual and timely processing.

Patent CN201120465105 discloses a measuring tool for aluminum electrolytic cells. The measuring electrodes are ordinary iron brazes. During use, solid electrolyte adheres to the iron brazes, so that the voltage change in the measurement circuit is no longer obvious, and through Manually judge the voltage change to determine the interface between the electrolyte and the aluminum liquid, the measurement accuracy is difficult to guarantee, and the labor load is large

Patent CN201420300651 discloses a measuring device for the height of the electrolyte and the height of the aluminum liquid in aluminum electrolysis. The essence is to change the method of obliquely inserting the iron solder into the melt vertically in the current manual measurement, which fails to solve the problem that the interface between the electrolyte and the aluminum liquid is on the surface of the solder Problems that are difficult to identify with the naked eye, measurement accuracy is still not guaranteed and labor-intensive

The temperature and aluminum liquid height measurement device for the aluminum electrolysis process applied for by the patent CN201410206118 uses a thermocouple as a temperature sensor, which has problems such as high-temperature molten salt corrosion and electrolyte adhesion to reduce sensitivity, which requires manual and timely processing. At the same time, due to temperature measurement The reaction hysteresis of the thermocouples in the process also leads to a decrease in the accuracy of the measurement results

Another example is a prebaked aluminum electrolytic cell process parameter measurement device proposed in patent ZL200610004044.7. Although it proposes automatic measurement of melt height and furnace bottom pressure drop, in practical applications, the measurement probe is easy to adhere to the electrolyte. shell, resulting in a decrease in the sensitivity of the probe, especially when there is too much solid electrolyte adhering to the melt and it is too late to dissolve, the measuring probe will lose its function, resulting in the paralysis of the entire measuring device

In addition, the trolley needs to be close to the electrolytic cell during the actual measurement, and the PLC and electronic devices in the controller are easily interfered by the strong magnetic field of the electrolytic cell, resulting in a decrease in measurement accuracy, and the structure of the device is complicated, the cost is high, and the operation is difficult. convenient

[0005] More importantly, since the electrolyte-aluminum liquid interface has been fluctuating during the actual operation of the electrolytic cell and there is a fuzzy diffusion layer at the interface, in the current patent for automatic measuring devices, only by analyzing the potential The change is that it is impossible to accurately judge the position of the electrolyte-aluminum liquid interface, which causes a large error in the measurement process of the device

Therefore, the above-mentioned automatic measuring device for melt height and furnace bottom pressure drop has not been widely used in actual production so far.

Images