A method for calculating the amount of aluminum fluoride added to aluminum electrolytic cells

Abstract

The present invention discloses a method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell, comprising the following steps: data preparation: collecting historical data of the electrolytic cell control system; cell type classification and management: dividing the electrolytic cell into different cell types according to the cathode material and the upper structure characteristics; base addition amount calculation: the cell age can be divided into the late start-up period and the normal period; target molecular ratio determination: sorting according to the electrolytic cell stability; adjustment required aluminum fluoride calculation: calculating the amount of aluminum fluoride added required to adjust to the target molecular ratio; daily aluminum fluoride adjustment amount calculation: calculating the raw material correction amount. The present invention comprehensively considers the balance of materials and energy, takes into account the individual properties of the electrolytic cell, selects a relatively low molecular ratio under the premise of the stability of the electrolytic cell, is conducive to improving the technical and economic indicators of the electrolytic cell operation, and uses the historical data of a single electrolytic cell to determine the base addition amount, which better eliminates the interference of frequently occurring factors such as the fixed container and fixed capacity of the electrolytic cell on the amount of aluminum fluoride added.

Description

Technical Field

[0001] The invention relates to the field of aluminum electrolytic cells, and in particular to a method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell. Background Art

[0002] Electrolyte is the solvent of the current aluminum electrolytic cell and the "blood" of the aluminum electrolysis reaction. It is responsible for conducting electricity, dissolving alumina, and maintaining thermal balance. Maintaining a relatively stable electrolyte composition, especially the molar ratio of sodium fluoride and aluminum fluoride, is of great significance to the stability and technical and economic indicators of the electrolytic cell. If the amount of aluminum fluoride added is insufficient, the molecular ratio will increase, the cell temperature will increase, and the current efficiency of the electrolytic cell will decrease. If the amount of added is too much, the molecular ratio will drop sharply, the stability of the electrolytic cell will deteriorate, the solubility of alumina will deteriorate, and the economic indicators such as current efficiency and aluminum fluoride unit consumption will deteriorate. Therefore, reasonable adjustment of the amount of aluminum fluoride added is not only to maintain the stability of the electrolyte composition and the operation of the electrolytic cell, but also to optimize the technical and economic indicators and reduce material consumption. An effective way. The existing addition methods can be divided into two categories: fixed value method and empirical method.

[0003] The fixed value method is to select different addition amounts according to the established formula after the molecular ratio analysis results come out. It has the following shortcomings:

[0004] 1. It cannot be adjusted according to the actual conditions of different electrolytic cells, and the molecular ratio of individual electrolytic cells often fluctuates;

[0005] 2. The amount of addition given in the electrolytic cell's operating technical conditions, raw materials, etc. has no guiding significance for production;

[0006] 3. The large amount of data wealth generated by existing production management systems such as slot control machines has not been fully tapped for comprehensive analysis and judgment, resulting in a waste of data wealth.

[0007] The empirical method is to use the on-site management personnel to give the amount of aluminum fluoride added based on their own production management experience combined with the molecular ratio analysis value and the tank control system operation data. It has the following shortcomings:

[0008] 1. It is completely based on the experience of on-site managers, and the amount of addition given by different personnel varies greatly;

[0009] 2. Manual analysis of big data such as slot control systems has insurmountable difficulties such as large workload and poor accuracy. Summary of the invention

[0010] The object of the present invention is to provide a method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell to solve the problems raised in the above-mentioned background technology.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell comprises the following steps:

[0013] Step S1, data preparation: collecting historical data of the electrolytic cell control system, including the cell temperature and electrolyte molecular ratio, conducting raw material inspection and testing to obtain the chemical composition and physical property data of aluminum fluoride and aluminum oxide, and collecting on-site measurement data, including the actual state of the electrolytic cell and historical change trends;

[0014] Step S2, cell type classification and management: the electrolytic cells are classified into different cell types according to the cathode material and superstructure characteristics, including high-graphite cathodes and graphitized cathodes, and the same electrolytic cells are classified into one category for classification management;

[0015] Step S3, calculation of the reference addition amount: according to the cell age, it can be divided into the late startup period and the normal period. For the electrolytic cells in the late startup period, the reference addition amount is the average addition amount of all electrolytic cells of the same type with a molecular ratio less than 3.0. For the electrolytic cells in the normal period, the aluminum fluoride molecular ratio analysis values ​​of the same manufacturer or quality brand in the last two months are sorted, and the average value of the aluminum fluoride addition amount with a molecular ratio within the technical conditions is selected as the reference addition amount;

[0016] Step S4, target molecular ratio determination: for the electrolytic cells managed in the normal period, the target molecular ratio is determined according to the stability ranking of the electrolytic cells. The top 20% cells with the best stability may be selected first, and the target molecular ratio is the molecular ratio analysis value minus 0.1. For the 20% to 80% cells with medium stability, the target molecular ratio is the molecular ratio analysis value minus 0.05. For the 80% cells with the worst stability, the target molecular ratio is the molecular ratio analysis value plus 0.1, but it shall not exceed the upper and lower limits of the molecular ratio range of the technical conditions.

[0017] Step S5, calculation of the required aluminum fluoride for adjustment: calculation of the amount of aluminum fluoride added required for adjustment to the target molecular ratio, the calculation formula being: the required amount of aluminum fluoride added for adjustment = 2*total amount of electrolyte*(last molecular ratio analysis value-target molecular ratio value) / (target molecular ratio value*(last molecular ratio analysis value+2));

[0018] Step S6, calculation of daily aluminum fluoride adjustment amount: calculate the raw material correction amount, including the difference between the sodium oxide content in the aluminum oxide during the period and the monthly average value, and other parameters; calculate the daily average aluminum fluoride addition during the period, including the baseline addition amount, the bulk density of aluminum fluoride, and the correction amount brought about by the change in the mass of aluminum fluoride and aluminum oxide; finally calculate the daily aluminum fluoride adjustment amount, including the volatility and electrolyte temperature correction rate, the operating voltage difference correction rate, and the series current correction rate.

[0019] Furthermore, in step S1, the total amount of electrolyte is calculated based on the total amount of liquid electrolyte according to the electrolytic cell furnace design parameters, the inter-electrode distance, the average furnace measurement data, the distance between the stratosphere and the bubble layer, and the electrolyte height.

[0020] Furthermore, in step S3, when the qualified range is 2.4 to 2.6, the average value of the aluminum fluoride addition amount within the molecular ratio range of 2.4 to 2.6 is selected as the reference addition amount.

[0021] Furthermore, in step S4, when the qualified range is 2.4 to 2.6, the minimum target molecular ratio is 2.4, and the maximum target molecular ratio is 2.6. If the molecular ratio of this analysis is lower than the lower limit, the target molecular ratio is calculated by adding 0.05 to the lower limit. When the analysis value is 2.3 and the lower limit of the qualified range is 2.4, the target value is 2.45. The molecular ratio of the first addition of aluminum fluoride in the later stage of startup is determined by subtracting 0.05 from the current analysis value until the molecular ratio analysis value is lower than the upper limit of the molecular ratio maintenance range and is included in the normal period electrolytic cell for management.

[0022] Furthermore, in step S6, the calculation formula of the raw material correction amount is as follows:

[0023] Raw material correction amount = (sodium oxide content in alumina during this period - monthly average sodium oxide content in alumina) * alumina consumption per ton of aluminum * (0.903 + 2.71 / target molecular ratio) * weekly average aluminum output per tank / (F + Al content in aluminum fluoride this week) / volume density of aluminum fluoride.

[0024] Furthermore, in step S6, the calculation formula for the average daily addition amount is as follows:

[0025] Average daily addition amount = single tank base daily aluminum fluoride addition amount + (total amount of aluminum fluoride required to adjust to the target molecular ratio / number of days in the cycle / bulk density of aluminum fluoride + correction amount due to changes in the mass of aluminum fluoride and alumina / bulk density of aluminum fluoride) * designed fixed capacity / actual weighed fixed capacity.

[0026] Furthermore, in step S6, the calculation formula for the daily amount of aluminum fluoride added is as follows:

[0027] Daily aluminum fluoride addition = daily average addition * (100-volatility and electrolyte temperature correction rate + operating voltage difference correction rate + series current correction rate).

[0028] Furthermore, in step S6, the volatility and electrolyte temperature correction rate are based on at least one month of technical condition data to sort the molecular ratios and cell temperatures of the electrolytic cells in the work area according to different cell types, and generate average cell temperatures corresponding to different molecular ratio ranges. If the average temperature corresponding to 2.45 is 945°C, and if the average temperature corresponding to 2.44 is 942°C, the cell temperature corresponding to the target molecular ratio is selected as the target cell temperature and adjusted according to the table below.

[0029] Furthermore, in step S6, the operating voltage difference is equal to the average daily working voltage of the electrolytic cell minus the average daily set voltage, which can characterize the stability and superheat of the electrolytic cell. When it exceeds a certain range, it means that the electrolytic cell has fluctuated and the superheat has increased. If the amount of aluminum fluoride added is not adjusted in time, the furnace wall will melt, the current efficiency will decrease, and the technical and economic indicators will be abused.

[0030] Furthermore, in step S6, the aluminum fluoride consumption increases when the series current increases, and the aluminum fluoride consumption decreases when the series current decreases and the bath temperature decreases.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention comprehensively considers the balance of materials and energy, takes into account the individual properties of the electrolytic cell, selects a relatively low molecular ratio under the premise of the stability of the electrolytic cell, which is conducive to improving the technical and economic indicators of the electrolytic cell operation, and uses the historical data of a single electrolytic cell to determine the benchmark addition amount, which better eliminates the interference of frequently occurring factors such as the fixed container and fixed capacity of the electrolytic cell with the addition amount of aluminum fluoride;

[0033] 2. The present invention comprehensively considers the factors affecting the cell temperature and the stability of the electrolytic cell in determining the target molecular ratio and the amount of aluminum fluoride added, so as to reduce the molecular ratio when the electrolytic cell is stable and the superheat is low to achieve the purpose of high current efficiency, and reduce the amount of aluminum fluoride added when the electrolytic cell fluctuates and the superheat increases to prevent the electrolytic cell furnace from melting and the index deterioration;

[0034] 3. The present invention draws the sodium oxide, moisture, aluminum fluoride, aluminum content and bulk density of the two raw materials of aluminum oxide and aluminum fluoride into the formula for calculation, which improves the accuracy of the method and the adaptability to changes in raw materials. The data items used are the daily data of the electrolytic cell control system, which can be collected by all enterprises; the algorithm is simple and the software program development is less difficult;

[0035] 4. The present invention introduces correction parameters for fixed containers, designs the aluminum fluoride fixed capacity / weighed fixed capacity or the average monthly aluminum fluoride feeding times of the electrolytic cell in a normal state / the feeding times of similar electrolytic cells in the work area, and corrects the adjustment amount to better solve the problem of the difference in the fixed capacity of aluminum fluoride fixed containers. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1The present invention is a schematic diagram of the overall process of a method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 1 , the present invention provides a technical solution:

[0039] A method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell comprises the following steps:

[0040] Step S1, data preparation: collecting historical data of the electrolytic cell control system, including the cell temperature and electrolyte molecular ratio, conducting raw material inspection and testing to obtain the chemical composition and physical property data of aluminum fluoride and aluminum oxide, and collecting on-site measurement data, including the actual state of the electrolytic cell and historical change trends;

[0041] In this embodiment, the total amount of electrolyte is the total amount of liquid electrolyte calculated based on the electrolytic cell furnace design parameters, pole distance, furnace measurement average data, the distance between the stratosphere and the bubble layer, and the electrolyte height.

[0042] Step S2, cell type classification and management: the electrolytic cells are classified into different cell types according to the cathode material and superstructure characteristics, including high-graphite cathodes and graphitized cathodes, and the same electrolytic cells are classified into one category for classification management;

[0043] Step S3, calculation of the reference addition amount: according to the cell age, it can be divided into the late startup period and the normal period. For the electrolytic cells in the late startup period, the reference addition amount is the average addition amount of all electrolytic cells of the same type with a molecular ratio less than 3.0. For the electrolytic cells in the normal period, the aluminum fluoride molecular ratio analysis values ​​of the same manufacturer or quality brand in the last two months are sorted, and the average value of the aluminum fluoride addition amount with a molecular ratio within the technical conditions is selected as the reference addition amount;

[0044] In this embodiment, when the qualified range is 2.4 to 2.6, the average value of the aluminum fluoride addition amount within the molecular ratio range of 2.4 to 2.6 is selected as the reference addition amount.

[0045] Step S4, target molecular ratio determination: for the electrolytic cells managed in the normal period, the target molecular ratio is determined according to the stability ranking of the electrolytic cells. The top 20% cells with the best stability may be selected first, and the target molecular ratio is the molecular ratio analysis value minus 0.1. For the 20% to 80% cells with medium stability, the target molecular ratio is the molecular ratio analysis value minus 0.05. For the 80% cells with the worst stability, the target molecular ratio is the molecular ratio analysis value plus 0.1, but it shall not exceed the upper and lower limits of the molecular ratio range of the technical conditions.

[0046] In this embodiment, when the qualified range is 2.4-2.6, the lowest target molecular ratio is 2.4, and the highest target molecular ratio is 2.6. If the molecular ratio of this analysis is lower than the lower limit, the target molecular ratio is calculated by adding 0.05 to the lower limit. When the analysis value is 2.3 and the lower limit of the qualified range is 2.4, the target value is 2.45. The molecular ratio of the first addition of aluminum fluoride in the later stage of startup is determined by subtracting 0.05 from the current analysis value, until the molecular ratio analysis value is lower than the upper limit of the molecular ratio maintenance range and is included in the normal period electrolytic cell for management.

[0047] Step S5, calculation of the required aluminum fluoride for adjustment: calculation of the amount of aluminum fluoride added required for adjustment to the target molecular ratio, the calculation formula being: the required amount of aluminum fluoride added for adjustment = 2*total amount of electrolyte*(last molecular ratio analysis value-target molecular ratio value) / (target molecular ratio value*(last molecular ratio analysis value+2));

[0048] Step S6, calculation of daily aluminum fluoride adjustment amount: calculating the raw material correction amount, including the difference between the sodium oxide content in aluminum oxide during the period and the monthly average value, and other parameters, calculating the daily average aluminum fluoride addition amount during the period, including the baseline addition amount, the bulk density of aluminum fluoride, and the correction amount brought in by the mass change of aluminum fluoride and aluminum oxide, and finally calculating the daily aluminum fluoride adjustment amount, including the volatility and electrolyte temperature correction rate, the operating voltage difference correction rate, and the series current correction rate;

[0049] In this embodiment, the calculation formula of the raw material correction amount is as follows:

[0050] Raw material correction amount = (sodium oxide content in alumina during this period - monthly average sodium oxide content in alumina) * unit consumption of alumina per ton of aluminum * (0.903 + 2.71 / target molecular ratio) * average aluminum output per tank per week / (F + Al content in aluminum fluoride this week) / volume density of aluminum fluoride;

[0051] In this embodiment, the calculation formula of the average daily addition amount is as follows:

[0052] Average daily addition amount = single tank base daily aluminum fluoride addition amount + (total amount of aluminum fluoride required to adjust to the target molecular ratio / number of days in the cycle / bulk density of aluminum fluoride + correction amount due to changes in the mass of aluminum fluoride and alumina / bulk density of aluminum fluoride) * designed fixed capacity / actual weighed fixed capacity;

[0053] In this embodiment, the calculation formula for the daily aluminum fluoride addition amount is as follows:

[0054] Daily aluminum fluoride addition = daily average addition * (100-volatility and electrolyte temperature correction rate + operating voltage difference correction rate + series current correction rate);

[0055] In this embodiment, the volatility and electrolyte temperature correction rate are based on at least one month's technical condition data to sort the molecular ratios and cell temperatures of the electrolytic cells in the work area according to different cell types, and generate average cell temperatures corresponding to different molecular ratio ranges. If the average temperature corresponding to 2.45 is 945°C, and if the average temperature corresponding to 2.44 is 942°C, the cell temperature corresponding to the target molecular ratio is selected as the target cell temperature and adjusted according to the following table; the operating voltage difference is equal to the average daily working voltage of the electrolytic cell minus the average daily set voltage, which can characterize the stability and overheat of the electrolytic cell. When it exceeds a certain range, it means that the electrolytic cell has fluctuated and the overheat has increased. If the amount of aluminum fluoride added is not adjusted in time, the furnace wall will melt, the current efficiency will decrease, and the technical and economic indicators will be abused; the aluminum fluoride consumption will increase when the series current increases, and the aluminum fluoride consumption will decrease when the series current decreases and the cell temperature decreases.

[0056] The data items are shown below:

[0057]

[0058]

[0059] The calculation formula is shown below:

[0060]

[0061]

[0062]

[0063] The fluctuation and tank temperature correction rate are shown below:

[0064]

[0065]

[0066] The operating voltage difference correction rate is shown as follows:

[0067]

[0068] The series current correction rate is shown below:

[0069]

[0070]

[0071] Embodiment 1

[0072] As shown in the table below, the recommended value for the amount of aluminum fluoride added to a 500KA series 1223# aluminum electrolytic cell is 68Kg, the molecular ratio in the last analysis was 2.62, the target molecular ratio was 2.58, and the value in this analysis was 2.56;

[0073]

[0074]

[0075] Embodiment 2

[0076] As shown in the table below, the recommended amount of aluminum fluoride added to another 500Ka series electrolytic cell 1143# electrolytic cell is 58Kg. The last analyzed molecular ratio was 2.7, the target this time was 2.60, and the analyzed value was 2.62;

[0077]

[0078]

[0079] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0080] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell, characterized in that: The following steps are involved: Step S1, data preparation: collecting historical data of the electrolytic cell control system, including the cell temperature and electrolyte molecular ratio, conducting raw material inspection and testing to obtain the chemical composition and physical property data of aluminum fluoride and aluminum oxide, and collecting on-site measurement data, including the actual state of the electrolytic cell and historical change trends; Step S2, cell type classification and management: the electrolytic cells are classified into different cell types according to the cathode material and superstructure characteristics, including high-graphite cathodes and graphitized cathodes, and the same electrolytic cells are classified into one category for classification management; Step S3, calculation of the reference addition amount: according to the cell age, it can be divided into the late startup period and the normal period. For the electrolytic cells in the late startup period, the reference addition amount is the average addition amount of all electrolytic cells of the same type with a molecular ratio less than 3.

0. For the electrolytic cells in the normal period, the aluminum fluoride molecular ratio analysis values ​​of the same manufacturer or quality brand in the last two months are sorted, and the average value of the aluminum fluoride addition amount with a molecular ratio within the technical conditions is selected as the reference addition amount; Step S4, target molecular ratio determination: for the electrolytic cells managed in the normal period, the target molecular ratio is determined according to the stability ranking of the electrolytic cells. The top 20% cells with the best stability may be selected first, and the target molecular ratio is the molecular ratio analysis value minus 0.

1. For the 20% to 80% cells with medium stability, the target molecular ratio is the molecular ratio analysis value minus 0.

05. For the 80% cells with the worst stability, the target molecular ratio is the molecular ratio analysis value plus 0.1, but it shall not exceed the upper and lower limits of the molecular ratio range of the technical conditions. Step S5, calculation of the required aluminum fluoride for adjustment: calculation of the amount of aluminum fluoride added required for adjustment to the target molecular ratio, the calculation formula being: the required amount of aluminum fluoride added for adjustment = 2*total amount of electrolyte*(last molecular ratio analysis value-target molecular ratio value) / (target molecular ratio value*(last molecular ratio analysis value+2)); Step S6, calculation of daily aluminum fluoride adjustment amount: calculating the raw material correction amount, including the difference between the sodium oxide content in aluminum oxide during the period and the monthly average value, and other parameters, calculating the daily average aluminum fluoride addition amount during the period, including the baseline addition amount, the bulk density of aluminum fluoride, and the correction amount brought in by the mass change of aluminum fluoride and aluminum oxide, and finally calculating the daily aluminum fluoride adjustment amount, including the volatility and electrolyte temperature correction rate, the operating voltage difference correction rate, and the series current correction rate; The calculation formula of the raw material correction amount is as follows: Raw material correction amount = (sodium oxide content in alumina during this period - monthly average sodium oxide content in alumina) * unit consumption of alumina per ton of aluminum * (0.903 + 2.71 / target molecular ratio) * average aluminum output per tank per week / (F + Al content in aluminum fluoride this week) / volume density of aluminum fluoride; The calculation formula for the daily average aluminum fluoride addition is as follows: Average daily aluminum fluoride addition = single tank base daily aluminum fluoride addition + (total amount of aluminum fluoride required to adjust to target molecular weight / number of days in cycle / bulk density of aluminum fluoride + correction amount due to mass change of aluminum fluoride and alumina / bulk density of aluminum fluoride) * designed fixed capacity / actual weighed fixed capacity; The calculation formula of the daily aluminum fluoride adjustment amount is as follows: Daily aluminum fluoride adjustment amount = daily average aluminum fluoride addition amount * (100-volatility and electrolyte temperature correction rate + operating voltage difference correction rate + series current correction rate).

2. The method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell according to claim 1, characterized in that: In step S1, the total amount of electrolyte is the total amount of liquid electrolyte calculated based on the electrolytic cell furnace design parameters, pole distance, furnace measurement average data, the distance between the stratosphere and the bubble layer, and the electrolyte height.

3. The method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell according to claim 1, characterized in that: In step S3, when the qualified range is 2.4 to 2.6, the average value of the aluminum fluoride addition amount within the molecular ratio range of 2.4 to 2.6 is selected as the reference addition amount.

4. The method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell according to claim 1, characterized in that: In step S4, when the qualified range is 2.4-2.6, the minimum target molecular ratio is 2.4, and the maximum target molecular ratio is 2.

6. If the molecular ratio of this analysis is lower than the lower limit, the target molecular ratio is calculated by adding 0.05 to the lower limit. When the analysis value is 2.3 and the lower limit of the qualified range is 2.4, the target value is 2.

45. The molecular ratio of the first addition of aluminum fluoride in the later stage of startup is determined by subtracting 0.05 from the current analysis value to determine the target molecular ratio, until the molecular ratio analysis value is lower than the upper limit of the molecular ratio maintenance range and is included in the normal period electrolytic cell for management.

5. The method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell according to claim 1, characterized in that: In step S6, the volatility and electrolyte temperature correction rate are obtained by sorting the molecular ratios and cell temperatures of the electrolytic cells in the work area according to different cell types using at least one month's technical condition data, and generating average cell temperatures corresponding to different molecular ratio ranges.

6. The method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell according to claim 1, characterized in that: In step S6, the operating voltage difference is equal to the average daily working voltage of the electrolytic cell minus the average daily set voltage, which can characterize the stability and superheat of the electrolytic cell. When it exceeds a certain range, it means that the electrolytic cell has fluctuated and the superheat has increased. If the amount of aluminum fluoride added is not adjusted in time, the furnace wall will melt, the current efficiency will decrease, and the technical and economic indicators will be abused.

7. The method for calculating the amount of aluminum fluoride added to an aluminum electrolytic cell according to claim 1, characterized in that: In the step S6, the aluminum fluoride consumption increases when the series current increases, and the aluminum fluoride consumption decreases when the series current decreases and the bath temperature decreases.

Images