CN109267108B

CN109267108B - Preparation method of aluminum-chromium alloy

Info

Publication number: CN109267108B
Application number: CN201811458465.6A
Authority: CN
Inventors: 许晶; 柴永成; 于水; 沈利; 高宝堂; 刘彬; 赵云飞; 夏增立; 温瑞宇; 谢长青; 白洁; 李超群; 徐晓光
Original assignee: Inner Mongolia Huayun New Material Co ltd; Baotou Aluminium Co ltd
Current assignee: Inner Mongolia Huayun New Material Co ltd; Baotou Aluminium Co ltd
Priority date: 2018-11-30
Filing date: 2018-11-30
Publication date: 2021-02-26
Anticipated expiration: 2038-11-30
Also published as: CN109267108A

Abstract

The invention provides a preparation method for obtaining an aluminum-chromium alloy by using chromium oxide as a main raw material and electrolyzing in an aluminum electrolysis cell. The invention only utilizes the existing prebaked anode aluminum electrolytic cell, and realizes the industrial batch continuous production of the aluminum-chromium alloy by the aluminum electrolytic cell under the condition of not increasing any equipment investment. The method can effectively control the fluctuation of the electrolytic production process caused by the violent reaction after the raw materials are added in a reasonable range, and can accurately control the chromium content in the aluminum-chromium alloy. The utilization rate of the chromium oxide raw material is high, and the obtained aluminum-chromium alloy has the characteristics of high content, small segregation and uniform components.

Description

Preparation method of aluminum-chromium alloy

The technical field is as follows:

the invention relates to a preparation method of an aluminum-chromium alloy, in particular to a preparation method of an aluminum-chromium alloy by using an aluminum electrolytic cell.

Background art:

at present, there are two main methods for industrially preparing aluminum-chromium alloy, namely, self-propagating aluminothermic reduction method and counter-doping method. The self-spreading aluminothermic reduction method is produced by utilizing the principle that chromium oxide and aluminum automatically react at a certain temperature, and has the following defects: the burning is violent in the production process, and the generated smoke has certain toxic action on human bodies; meanwhile, the aluminothermic reduction method is to use chromium oxide as a raw material and metal aluminum as a reducing agent to perform reduction reaction at high temperature to produce the aluminum-chromium alloy, but the aluminum oxide replaced by the method is slag, so that the aluminum loss is serious, the slag is difficult to remove, the melt quality is poor, and the defects of the produced aluminum-chromium alloy are serious. The doping method has two modes: firstly, chromium-containing chromium additive is used for mixing with pure aluminum, the chromium additive is composed of pure chromium and combustion improver, and the method has the following defects: the chromium additive can generate a large amount of smoke in the adding process, so that serious pollution is caused, and meanwhile, the chromium yield is low and the cost is high; secondly, the pure chromium and the pure aluminum are used for doping, and the method has the defects of low actual yield of chromium, serious component segregation and difficult control of component content.

In addition, molten salt electrolysis has been carried out in laboratories to produce aluminium-chromium alloys. However, the laboratory adopts small containers such as crucibles, the technological conditions of the small containers are greatly different from the industrial environment, the small containers do not have the condition of being transplanted into an industrial electrolytic bath, and the small containers cannot form stable and continuous aluminum-chromium alloy productivity.

Patent CN201610104761 discloses a process for producing alloy aluminum in an aluminum electrolysis cell by using aluminum reduction alloy oxide, which is to add oxide of required alloy elements into aluminum liquid in the aluminum electrolysis cell through a dielectric layer in the aluminum electrolysis production process. The alloy element is an alloy element with stronger oxidability than aluminum; the method for putting the oxides of the alloy elements into the molten aluminum comprises the following steps: when the electrode is changed, the anode is added from the opened anode opening, added from the fire hole opening or added by another opening.

There are problems that: firstly, in alloy elements with oxidability stronger than that of aluminum, if chromium reacts violently with aluminum, the change of technical conditions of an electrolysis process is easily caused by excessive feeding amount, and the normal electrolysis production is influenced; meanwhile, in the electrolytic production process, a certain amount of original aluminum liquid needs to be extracted from the stock aluminum of the electrolytic cell every day for casting, so that the dynamic balance process is realized, and the content of metal elements in the stock aluminum can be stably improved by taking full consideration. Aiming at the situation, scientific and reasonable feeding amount needs to be designed to stabilize the production process, and simultaneously, the content of metal elements in the stock aluminum is increased according to expectation. The patent does not explicitly give a method for controlling and calculating the amount of the feed, and the purpose of the patent is not easily achieved by the method.

Secondly, the oxide of the needed alloy element is added into the aluminum liquid in the aluminum electrolytic cell through the dielectric layer, and the practical situation is that the electrolyte layer is arranged above the aluminum liquid layer in the electrolytic cell, and the electrolyte layer is flowing and has the characteristics of high temperature, strong corrosivity and the like. The device can realize stable and continuous corrosion resistance and high temperature resistance which can penetrate through the electrolyte layer and be added into the aluminum liquid layer, and the content mentioned in the patent is not easy to realize.

Thirdly, for the charging time point, because a certain amount of raw aluminum liquid needs to be extracted from the stock aluminum of the electrolytic cell every day for casting, the dynamic balance process is adopted, if the charging time is improper, the added metal element oxide can be extracted along with the daily raw aluminum without complete reaction, so that the unnecessary consumption of raw materials is caused, and the pollution of the raw aluminum liquid and the increase of the cost are caused.

The invention content is as follows:

in order to overcome the defects in the background technology, the invention aims to provide a method for realizing the industrial batch continuous production of aluminum-chromium alloy by using an aluminum electrolytic cell by fully utilizing a pre-baked anode aluminum electrolytic cell in production and directly adding chromium oxide in the aluminum electrolytic process. The method has the advantages of stable production, low energy consumption, high efficiency and high quality.

The purpose of the invention is implemented by the following technical scheme: a preparation method of aluminum-chromium alloy is prepared by an aluminum electrolytic cell, and comprises the following steps: (1) measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein the nNaF. AlF₃62 to 94 percent; KF is 0.1-8%; CaF₂1-8%; MgF₂1-8%; LiF accounts for 1-8%; AL₂O₃2-7%, wherein the sum of the mass percentages of the components is 100%; (2) when the measured values are within the above ranges, chromium oxide is added and the technical conditions of the electrolytic process are detected and maintained: the electrolysis temperature is 900-960 ℃, the average voltage is 3.5-4.3V, and the aluminum-chromium alloy is obtained.

Further, according to the step (2), adding chromium oxide into the aluminum electrolytic cell, wherein the electrolytic process comprises at least one aluminum-chromium alloy electrolysis cycle, and the one aluminum-chromium alloy electrolysis cycle comprises: a chromium content rising period and a chromium content balancing period; wherein the chromium content rising period is an electrolysis process before the mass percent content of chromium in aluminum stored in the aluminum electrolysis cell reaches a set value, and the mass percent content of chromium in stored aluminum continuously rises at the stage; the chromium content balancing period is an electrolysis process after the mass percentage content of chromium in the aluminum stored in the aluminum electrolysis cell reaches a set value, and the mass percentage content of chromium in the stored aluminum is kept unchanged at the stage.

Further, in the chromium content rising period in the electrolysis process, chromium oxide is added, and the specific steps comprise:

determining the daily lifting rate of the chromium content according to the content of chromium in the aluminum measured in the current electrolytic cell by detection and analysis; calculating the daily feeding amount of chromium oxide during the rising period of the chromium content

The daily charge of chromium oxide in the chromium content rise period is calculated by the following formula:

wherein, W_{Lifting of wine}The daily charge (kg) of chromium oxide during the chromium content rise, Q_DishThe mass (kg) of aluminum stored in the aluminum cell, a₁Is the actual detection value (%) of the mass percent content of chromium in the aluminum in the internal memory of the aluminum electrolytic cell on the day a₂The mass percent (%) of chromium in the aluminum cell memory amount expected to be reached the next day (a)₂-a₁) The daily rate of increase (%) of the chromium content, Q_{Product produced by birth}The method comprises the steps of determining the sunrise aluminum amount (kg) of the aluminum electrolytic cell, determining P as the raw material utilization rate (%) of chromium oxide, determining C as the purity (%) of the chromium oxide, and determining m as the mass percent content (%) of chromium in the chromium oxide.

Further, when the chromium content of the aluminum in the electrolytic cell is less than 1.5 percent by mass, the daily lifting rate of the chromium content is less than or equal to 0.3 percent per day; when the chromium content of the aluminum stored in the electrolytic cell is more than or equal to 1.5% and less than 2.8%, the daily lifting rate of the chromium content is less than or equal to 0.15%/day.

Further, in the rising period of the chromium content, the feeding amount of the chromium oxide in unit hour is less than or equal to I/b; wherein, I is a series current (kA), and b is a constant satisfying: b is 10 kA/kg.

Further, in the chromium content rising period in the electrolysis process, the addition time of the chromium oxide is as follows: the starting point of daily addition of chromium oxide is after the aluminium is tapped from the aluminium electrolysis cell.

Further, in the chromium content balance period, the chromium content of the aluminum in the aluminum cell is controlled to be kept unchanged, and the method specifically comprises the following steps:

the daily charge of chromium oxide is calculated during the equilibrium period of the chromium content

The daily charge calculation formula of the chromium oxide in the equilibrium period of the chromium content is as follows:

wherein, W_{Flat plate}The daily charge (kg), Q, of chromium oxide in the equilibrium period of the chromium content_{Product produced by birth}The sunrise aluminum amount (kg) of the aluminum electrolytic cell, a_{Flat plate}The mass percent of chromium in aluminum in the aluminum cell memory amount in the balance period of the chromium content (%) is shown as follows, P is the raw material utilization rate (%) of chromium oxide, C is the purity (%) of chromium oxide, and m is the mass percent of chromium in chromium oxide (%).

Further, in the chromium content balancing period, the feeding amount of the chromium oxide in unit hour is less than or equal to I/b; wherein, I is a series current (kA), and b is a constant satisfying: b is 10 kA/kg.

Further, during the balance period of the chromium content in the electrolysis process, the addition time of the chromium oxide is as follows: the starting point of daily addition of chromium oxide is after the aluminium is tapped from the aluminium electrolysis cell.

Further, the oxide of chromium is CrO₂，Cr₂O₃Either one or a combination of both.

Further, the aluminum electrolytic cell is a prebaked anode aluminum electrolytic cell.

The raw material utilization of chromium oxide refers to the percentage of the total amount of chromium in the produced aluminium-chromium alloy to the total amount of chromium in the chromium oxide added to the electrolytic cell.

The invention has the advantages that: the method has the main advantages that no redundant by-product is generated, the raw material loss is extremely low, the production cost is greatly reduced, the aluminum electrolysis cell can be continuously produced, and the product productivity is high; the magnetic field of the aluminum cell provides stirring power for the full dispersion of chromium in aluminum, and the produced aluminum-chromium alloy has uniform components and high product quality; the invention avoids the problems of large fluctuation of technological conditions, abnormal operation and the like caused by intense aluminothermic reduction reaction between chromium oxide and aluminum in the aluminum electrolytic cell by strictly controlling the feeding amount and the feeding mode of the chromium oxide, maintains the technological conditions of the aluminum electrolytic cell in a reasonable range, ensures the stable operation of the aluminum electrolytic cell in the process of preparing the aluminum-chromium alloy by electrolysis, and has the characteristic of short production flow when the aluminum-chromium alloy is prepared by a direct electrolysis method;

the invention only utilizes the existing prebaked anode aluminum electrolytic cell, can accurately control the chromium content in the aluminum-chromium alloy without adding any equipment investment, has high utilization rate of chromium raw materials, and obtains the aluminum-chromium alloy with uniform components.

The specific implementation mode is as follows:

the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: a preparation method of aluminum-chromium alloy with 1 percent of chromium by mass is characterized in that an aluminum cell is used for preparation, the aluminum cell used in the embodiment is a prebaked anode aluminum cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the cell type of the aluminum cell is a cradle type cell, and the series current is 200 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The technical conditions of the electrolytic cell are as follows: the average voltage was 3.642V, and the electrolysis temperature was 933 ℃.

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 0.8 percent; CaF₂5.1 percent; MgF₂2.1 percent; LiF is 5.5%; AL₂O₃5.2 percent; the balance of cryolite nNaF. AlF₃N is 2.44, and the sum of the mass percent of the components is 100 percent;

step 2: the electrolytic process of this embodiment comprises an aluminum chromium alloy electrolysis cycle, wherein an aluminum chromium alloy electrolysis cycle comprises: a chromium content rising period and a chromium content balancing period; wherein the chromium content rising period is an electrolysis process before the mass percent content of chromium in aluminum stored in the aluminum electrolysis cell reaches 1%, and the mass percent content of chromium in stored aluminum continuously rises at the stage; the chromium content balancing period is the electrolysis process after the mass percent content of chromium in the aluminum stored in the aluminum electrolysis cell reaches 1 percent, and the mass percent content of chromium in the stored aluminum is kept unchanged at the stage.

2.1 in the chromium content rising period and the balance period, the feeding amount of the chromium oxide in unit hour is less than or equal to I/b; wherein, I is a series current (kA), and b is a constant satisfying: b is 10 kA/kg; in the embodiment, the feeding amount of the chromium oxide in unit hour is calculated to be less than or equal to 20 kg;

2.2 in the chromium content rising period in the electrolysis process, adding chromium oxide, detecting and analyzing that the chromium content in the aluminum in the current electrolytic cell memory amount is 0, the target content is 1%, and determining the daily rising rate of the chromium content to be 0.1%/day. The method comprises the following specific steps:

2.2.1 chromium content rise period, day 1 chromium oxide addition operation

2.2.1.1 calculation of the daily dosage of chromium oxide during the chromium content Up phase 1

In this embodiment, Q_Dish10500 kg; a is₁The content of the active carbon is 0% by spectral analysis; due to a₂-a₁When the ratio is 0.1%, a is determined₂0.1 percent; q_{Product produced by birth}1460 kg; day 1P was set to 100%; c is 99%(ii) a m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}It was 17.66 kg.

2.2.1.2 according to the step 2.1, in the chromium content rising period, the feeding amount of the chromium oxide in unit hour is less than or equal to 20 kg; in the embodiment, the feeding amount of the 1 st day is 17.66kg, and the feeding operation can be completed within 1 hour;

2.2.1.3 when the measured values meet the requirements of step 1, adding chromium oxide to the prebaked anode aluminum reduction cell according to the calculation results of steps 2.2.1.1 and 2.2.1.2, wherein the starting time point of the daily addition of the chromium oxide is after aluminum tapping of the aluminum reduction cell.

After the feeding is finished on the 1 st day, the mass percent of chromium in the aluminum cell is actually 0.0933% through spectral analysis and detection, and the actual value of the utilization rate of the raw materials of the chromium oxide on the 1 st day is determined to be 93.3%.

2.2.2 chromium content rise period, day 2 chromium oxide addition operation

2.2.2.1 calculate the daily feed of chromium oxide during the chromium rise

in this embodiment, Q_Dish10500 kg; a is₁The content of the active ingredient is 0.0933% by spectral analysis; due to a₂-a₁When the ratio is 0.1%, a is determined₂0.1933%; q_{Product produced by birth}1460 kg; the actual value of the utilization rate of the raw materials of the chromium oxide adopted in the day 1 on the day 2P is 93.3 percent; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}It was 21.08 kg.

2.2.2.2 according to the step 2.1, in the chromium content rising period, the feeding amount of the chromium oxide in unit hour is less than or equal to 20 kg; the feeding amount of chromium oxide on day 2 in the example is 21.08kg, and the feeding operation needs to be completed within 2 hours;

2.2.2.3 when the measured value meets the requirement of step 1, the result is calculated according to steps 2.2.2.1 and 2.2.2.2, the chromium oxide is added into the prebaked anode aluminum reduction cell, and the starting time point of the daily addition of the chromium oxide is after the aluminum is discharged from the aluminum reduction cell.

After the feeding is finished on the 2 nd day, the mass percent of chromium in the aluminum cell is actually 0.1931% through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 2 nd day is determined to be 93.1%.

2.2.3 chromium content rise period, day 3 chromium oxide addition operation

2.2.3.1 calculation of the daily dosage of chromium oxide during the chromium rise

in this embodiment, Q_Dish10500 kg; a is₁0.1931% by spectroscopic analysis; due to a₂-a₁When the ratio is 0.1%, a is determined₂0.2931%; q_{Product produced by birth}1460 kg; the average value of the actual values of the raw material utilization rates of chromium oxides on day 1 and day 2 was 93.2% on day 3P; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}It was 23.41 kg.

2.2.3.2 according to step 2.1, in the chromium content rising period, the feeding amount of chromium oxide per hour is less than or equal to 20 kg; the feeding amount of chromium oxide on day 3 in this example was 23.41kg, and the feeding operation was completed in 2 hours;

2.2.3.3 when the measured value meets the requirement of the step 1, adding chromium oxide into the prebaked anode aluminum reduction cell according to the calculation results of the steps 2.2.3.1 and 2.2.3.2, wherein the starting time point of the daily addition of the chromium oxide is after the aluminum of the aluminum reduction cell is discharged.

After the feeding is finished on the 3 rd day, the mass percent of chromium in the aluminum cell is actually 0.2931% through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 3 rd day is determined to be 93.2%.

And then calculating and feeding materials according to a third day method every day, wherein the specific process is not repeated until the mass percentage content of chromium in the aluminum in the memory amount of the aluminum electrolytic cell reaches 1 percent. In this example, the average value of the actual values of the raw material utilization rates of chromium oxides in the chromium content rise period in the electrolysis process was 93.2%.

2.3 when the mass percent of the chromium in the aluminum cell reaches 1 percent, starting to feed according to the balance period of the chromium content. During the balance period of the chromium content in the electrolytic process, chromium oxide is added, and the method specifically comprises the following steps:

2.3.1 calculate the daily charge of chromium oxide during the equilibrium period of the chromium content

In this embodiment, Q_{Product produced by birth}1460 kg; a is_{Flat plate}Is 1%; in the period that the content of P in the chromium is increased, the average value of the actual values of the utilization rate of the raw materials of the chromium oxide is 93.2 percent; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (2)_{Flat plate}It was 23.13 kg.

2.3.2 according to the step 2.1, in the balance period of the chromium content, the feeding amount of the chromium oxide in unit hour is less than or equal to 20 kg; in the embodiment, the feeding amount of chromium oxide per day in the balance period is 23.13kg, and the feeding operation needs to be completed within 2 hours;

2.3.3 when the measured value meets the requirement of the step 1, adding chromium oxide into the prebaked anode aluminum reduction cell according to the calculation results of the steps 2.3.1 and 2.3.2, wherein the starting time point of daily addition of the chromium oxide is after aluminum tapping of the aluminum reduction cell.

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 1460kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 1%; the deviation of the mass percentage content of the chromium is less than 0.01 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 93.2 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.2 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

Example 2: a preparation method of aluminum-chromium alloy with 1 percent of chromium by mass is characterized in that an aluminum cell is used for preparation, the aluminum cell used in the embodiment is a prebaked anode aluminum cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the cell type of the aluminum cell is a cradle type cell, and the series current is 200 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The technical conditions of the electrolytic cell are as follows: the average voltage was 3.642V, and the electrolysis temperature was 933 ℃.

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃；KF；CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 4.1 percent; CaF₂2.1 percent; MgF₂4.8 percent; LiF is 2.5%; AL₂O₃2.2 percent; the balance of cryolite nNaF. AlF₃N is 2.77, and the sum of the mass percent of the components is 100 percent;

the other steps were the same as in example 1.

The aluminum-chromium alloy prepared by electrolysis by the embodiment has the chromium content deviation less than 0.01 percent and uniform components; the actual raw material utilization rate of the chromium oxide reaches 93.2 percent; the current efficiency is 91.3%; 1460kg of aluminum-chromium alloy can be produced in a single electrolytic tank every day, and the mass percent of chromium in the aluminum-chromium alloy is 1 percent.

Example 3: a preparation method of aluminum-chromium alloy with 1 percent of chromium by mass is characterized in that an aluminum cell is used for preparation, the aluminum cell used in the embodiment is a prebaked anode aluminum cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the cell type of the aluminum cell is a cradle type cell, and the series current is 200 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The technical conditions of the electrolytic cell are as follows: the average voltage was 4.028V and the electrolysis temperature was 948 ℃.

The specific process steps are the same as in example 1.

The aluminum-chromium alloy prepared by electrolysis by the embodiment has the chromium content deviation less than 0.01 percent and uniform components; the actual raw material utilization rate of the chromium oxide reaches 93.1 percent; the current efficiency is 91.2%; 1460kg of aluminum-chromium alloy can be produced in a single electrolytic tank every day, and the mass percent of chromium in the aluminum-chromium alloy is 1 percent.

Example 4: a method for preparing aluminum-chromium alloy with chromium content of 1.5% by mass uses an aluminum cell, the aluminum cell used in the embodiment is a prebaked anode aluminum cell, the adopted anode is a carbon anode, the cathode is a semi-graphite cathode, the cell type of the aluminum cell is a rectangular cell, the series current is 320KA, and the oxide of chromium in the embodiment is CrO₂The purity was 99%. The technical conditions of the electrolytic cell are as follows: the average voltage was 3.998V, and the electrolysis temperature was 918 ℃.

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 5.1 percent; CaF₂2.1 percent; MgF₂3.1 percent; LiF is 4.5%; AL₂O₃2.2 percent; the balance of cryolite nNaF. AlF₃N is 2.73, and the sum of the mass percent of the components is 100 percent;

step 2: the electrolytic process of this embodiment comprises an aluminum chromium alloy electrolysis cycle, wherein an aluminum chromium alloy electrolysis cycle comprises: a chromium content rising period and a chromium content balancing period; wherein the chromium content rising period is an electrolysis process before the mass percent content of chromium in aluminum stored in the aluminum electrolysis cell reaches 1.5 percent, and the mass percent content of chromium in stored aluminum at the stage continuously rises; the chromium content balancing period is the electrolysis process after the mass percent content of chromium in the aluminum stored in the aluminum electrolysis cell reaches 1.5 percent, and the mass percent content of chromium in the stored aluminum is kept unchanged at the stage.

2.1 in the chromium content rising period and the balance period, the feeding amount of the chromium oxide in unit hour is less than or equal to I/b; wherein, I is a series current (kA), and b is a constant satisfying: b is 10 kA/kg; in the embodiment, the feeding amount of the chromium oxide in unit hour is calculated to be less than or equal to 32 kg;

2.2 in the chromium content rising period in the electrolysis process, adding chromium oxide, detecting and analyzing that the chromium content in the aluminum in the current electrolytic cell memory amount is 0, the target content is 1.5%, and determining the daily rising rate of the chromium content to be 0.2%/day. The method comprises the following specific steps:

2.2.1 chromium content rise period, day 1 chromium oxide addition operation

wherein, W_{Lifting of wine}The daily charge (kg) of chromium oxide during the chromium content rise, Q_DishThe mass (kg) of aluminum stored in the aluminum cell, a₁Is the actual detection value (%) of the mass percent content of chromium in the aluminum in the internal memory of the aluminum electrolytic cell on the day a₂The mass percent (%) of chromium in the aluminum cell memory amount expected to be reached the next day (a)₂-a₁) The daily rate of increase (%) of the chromium content, Q_{Product produced by birth}The sunrise aluminum amount (kg) of the aluminum cell, P is the raw material utilization rate (%) of chromium oxide, and C is the oxygen of chromiumThe purity (%) of the compound, and m is the mass% of chromium in the chromium oxide.

In this embodiment, Q_Dish16200 kg; a is₁The content of the active carbon is 0% by spectral analysis; due to a₂-a₁When the ratio is 0.2%, a is determined₂0.2 percent; q_{Product produced by birth}2355 kg; day 1P was set to 100%; c is 99%; m is through CrO₂Molecular formula, calculated as 61.9%; w is calculated by the formula (1)_{Lifting of wine}60.56 kg.

2.2.1.2 according to the step 2.1, in the chromium content rising period, the feeding amount of the chromium oxide in unit hour is less than or equal to 32 kg; the oxide feeding amount of the day 1 in the embodiment is 60.56kg, and the feeding operation needs to be completed within 2 hours;

After the feeding is finished on the 1 st day, the mass percent of chromium in the aluminum cell is actually 0.185% through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 1 st day is determined to be 92.5%.

2.2.2 chromium content rise period, day 2 chromium oxide addition operation

2.2.2.1 calculate the daily feed of chromium oxide during the chromium rise

in this embodiment, Q_Dish16200 kg; a is₁Detected by spectral analysis to be 0.185%; due to a₂-a₁When the ratio is 0.2%, a is determined₂0.385%; q_{Product produced by birth}2355 kg; the actual value of the utilization rate of the raw materials of the chromium oxide adopted on day 2P and day 1 is 92.5%; c is 99%; m is through CrO₂Molecular formula, calculated as 61.9%; w is calculated by the formula (1)_{Lifting of wine}It was 73.15 kg.

2.2.2.2 according to the step 2.1, in the chromium content rising period, the feeding amount of the chromium oxide in unit hour is less than or equal to 32 kg; the feeding amount of chromium oxide on day 2 in this example was 73.15kg, and the feeding operation was completed in 3 hours;

After the feeding is finished on the 2 nd day, the mass percent of chromium in the aluminum cell is actually 0.386 percent through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 2 nd day is determined to be 92.9 percent.

2.2.3 chromium content rise period, day 3 chromium oxide addition operation

in this embodiment, Q_Dish16200 kg; a is₁The content of the active carbon is 0.386 percent through spectral analysis; due to a₂-a₁0.2%, determine a2 of 0.586%; q_{Product produced by birth}2355 kg; the average value of the actual values of the raw material utilization rates of chromium oxides on day 1 and day 2 was 92.7% on day 3P; c is 99%; m is through CrO₂Molecular formula, calculated as 61.9%; w is calculated by the formula (1)_{Lifting of wine}81.33 kg.

2.2.3.2 according to step 2.1, in the chromium content rising period, the feeding amount of chromium oxide per hour is less than or equal to 32 kg; the feeding amount of chromium oxide on day 3 in this example was 81.33kg, and the feeding operation required to be completed within 3 hours;

After the feeding is finished on the 3 rd day, the mass percent of chromium in the aluminum cell is actually 0.587% through the spectral analysis and detection, and the 3 rd day actual value of the utilization rate of the raw material of the chromium oxide is determined to be 92.9%.

And then calculating and feeding materials according to a third day method every day, wherein the specific process is not repeated until the mass percentage content of chromium in the aluminum in the memory amount of the aluminum electrolytic cell reaches 1.5 percent. In this example, the average value of the actual values of the raw material utilization rates of chromium oxides in the chromium content rising period in the electrolysis process was 92.8%.

2.3 when the mass percent of the chromium in the aluminum cell reaches 1.5 percent, starting feeding according to the balance period of the chromium content. During the balance period of the chromium content in the electrolytic process, chromium oxide is added, and the method specifically comprises the following steps:

In this embodiment, Q_{Product produced by birth}2355 kg; a is_{Flat plate}1.5 percent; in the period that the content of P in the chromium is increased, the average value of the actual values of the utilization rate of the raw materials of the chromium oxide is 92.8 percent; c is 99%; m is through CrO₂Molecular formula, calculated as 61.9%; w is calculated by the formula (2)_{Flat plate}It was 62.12 kg.

2.3.2 according to the step 2.1, in the balance period of the chromium content, the feeding amount of the chromium oxide in unit hour is less than or equal to 32 kg; in the embodiment, the feeding amount of the chromium oxide is 62.12kg per day in the balance period, and the feeding operation needs to be completed within 2 hours;

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 2355kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 1.5%; the mass percentage deviation of the chromium is less than 0.02 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 92.8 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.4 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

Example 5: a method for preparing aluminum-chromium alloy with chromium content of 1.5% by mass uses an aluminum cell, the aluminum cell used in the embodiment is a prebaked anode aluminum cell, the adopted anode is a carbon anode, the cathode is a semi-graphite cathode, the cell type of the aluminum cell is a rectangular cell, the series current is 320KA, and the oxide of chromium in the embodiment is CrO₂The purity was 99%. The technical conditions of the electrolytic cell are as follows: the average voltage was 3.998V, and the electrolysis temperature was 918 ℃.

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 1.8 percent; CaF₂3.1 percent; MgF₂4.7 percent; LiF is 5.2%; AL₂O₃4.6 percent; the balance of cryolite nNaF. AlF₃N is 2.28, and the sum of the mass percentages of the components is 100 percent.

The other steps were the same as in example 4.

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 2355kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 1.5%; the mass percentage deviation of the chromium is less than 0.02 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 92.9 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.4 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

Example 6: a method for preparing aluminum-chromium alloy with chromium content of 1.5% by mass uses an aluminum cell, the aluminum cell used in the embodiment is a prebaked anode aluminum cell, the adopted anode is a carbon anode, the cathode is a semi-graphite cathode, the cell type of the aluminum cell is a rectangular cell, the series current is 320KA, and the oxide of chromium in the embodiment is CrO₂The purity was 99%. The technical conditions of the electrolytic cell are as follows: the average voltage is 3.451V, and the electrolysis temperature is 948 ℃.

The rest is the same as in example 4.

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 2355kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 1.5%; the mass percentage deviation of the chromium is less than 0.02 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 92.6 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.4 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

Example 7: a preparation method of aluminum-chromium alloy with 2.8 percent of chromium by mass percent is characterized in that an aluminum electrolytic cell is used for preparation, the electrolytic cell used in the embodiment is a prebaked anode aluminum electrolytic cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the electrolytic cell is a cradle type cell, and the series current of the electrolytic cell is 600 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The main technical conditions of the electrolytic cell are as follows: the average voltage is 3.625V, and the electrolysis temperature is 915℃。

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 4.1 percent; CaF₂1.7 percent; MgF₂2.1 percent; LiF is 5.3%; AL₂O₃2.6 percent; the balance of cryolite nNaF. AlF₃N is 2.82, and the sum of the mass percentages of the components is 100 percent;

step 2: the electrolytic process of this example comprises two aluminum chromium alloy electrolysis cycles, wherein one aluminum chromium alloy electrolysis cycle comprises: a chromium content rising period and a chromium content balancing period; in the first aluminum-chromium alloy electrolysis period, the chromium content rising period is an electrolysis process before the mass percent content of chromium in the aluminum storage of the aluminum electrolysis cell reaches 1.5%, and the mass percent content of chromium in the aluminum storage of the aluminum electrolysis cell continuously rises at the stage; the chromium content balancing period is an electrolysis process after the mass percent of chromium in the aluminum stock of the aluminum electrolysis cell reaches 1.5%, and the mass percent of chromium in the aluminum stock is kept unchanged at the stage; in the first aluminum-chromium alloy electrolysis cycle, the duration of the chromium content balance period is 10 electrolysis working days; in the second aluminum-chromium alloy electrolysis period, the chromium content rising period is an electrolysis process in which the mass percent of chromium in the aluminum stock of the aluminum electrolysis cell is from 1.5% to 2.8%, and the mass percent of chromium in the aluminum stock at the stage continuously rises; the chromium content balancing period is an electrolysis process after the mass percent of chromium in the aluminum stock of the aluminum electrolysis cell reaches 2.8%, and the mass percent of chromium in the aluminum stock is kept unchanged at the stage;

2.1 in the chromium content rising period and the balance period, the feeding amount of the chromium oxide in unit hour is less than or equal to I/b; wherein, I is a series current (kA), and b is a constant satisfying: b is 10 kA/kg; in this example, the amount of chromium oxide charged per hour was calculated to be less than or equal to 60 kg;

2.2 in the first chromium content rising period in the electrolysis process, in the electrolysis process that the mass percentage content of chromium in the aluminum stored in the aluminum electrolysis cell is from 0 to 1.5 percent, adding chromium oxide, detecting and analyzing that the content of chromium in the aluminum stored in the current electrolysis cell is 0, the target content is 1.5 percent, and determining the daily lifting rate of the chromium content to be 0.3 percent/day. The method comprises the following specific steps:

2.2.1 chromium content rise period, day 1 chromium oxide addition operation

In this embodiment, Q_Dish40200 kg; a is₁The content of the active carbon is 0% by spectral analysis; due to a₂-a₁0.3%, determine a₂0.3 percent; q_{Product produced by birth}4410 kg; day 1P was set to 100%; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}197.58 kg.

2.2.1.2 according to the step 2.1, in the chromium content rising period, the feeding amount of the chromium oxide in unit hour is less than or equal to 60 kg; the feeding amount of the 1 st day in the embodiment is 197.58kg, and the feeding operation can be completed within 4 hours;

After the feeding is finished on the 1 st day, the mass percent of chromium in the aluminum cell is actually 0.2763% through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 1 st day is determined to be 92.1%.

2.2.2 chromium content rise period, day 2 chromium oxide addition operation

2.2.2.1 calculate the daily feed of chromium oxide during the chromium rise

in this embodiment, Q_Dish40200 kg; a is₁0.2763% by spectroscopic analysis; due to a₂-a₁0.3%, determine a₂0.5763%; q_{Product produced by birth}4410 kg; the actual value of the utilization rate of the raw materials of the chromium oxide adopted on day 2P and day 1 is 92.1%; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}234.06 kg.

2.2.2.2 according to the step 2.1, in the chromium content rising period, the feeding amount of the chromium oxide in unit hour is less than or equal to 60 kg; the feeding amount of chromium oxide on day 2 in this example was 234.06kg, and the feeding operation required to be completed within 4 hours;

After the feeding is finished on the 2 nd day, the mass percent of chromium in the aluminum cell is actually 0.5777% through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 2 nd day is determined to be 92.5%.

2.2.3 chromium content rise period, day 3 chromium oxide addition operation

in this embodiment, Q_Dish40200 kg; a is₁0.5777% by spectroscopic analysis; due to a₂-a₁0.3%, determine a₂0.8777%; q_{Product produced by birth}4410 kg; the average value of the actual values of the raw material utilization rates of chromium oxides on day 1 and day 2 was 92.3% on day 3P; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}254.81 kg.

2.2.3.2 according to step 2.1, in the chromium content rising period, the feeding amount of chromium oxide per hour is less than or equal to 60 kg; the feeding amount of chromium oxide on day 3 in this example was 254.81kg, and the feeding operation required completion within 5 hours;

After the feeding is finished on the 3 rd day, the mass percent of chromium in the aluminum cell is actually 0.8773% through the spectral analysis and detection, and the actual value of the utilization rate of the raw material of the chromium oxide on the 3 rd day is determined to be 92.2%.

And then calculating and feeding materials according to a third day method every day, wherein the specific process is not repeated until the mass percentage content of chromium in the aluminum in the memory amount of the aluminum electrolytic cell reaches 1.5 percent. In this example, the average value of the actual values of the raw material utilization rates of chromium oxides in the chromium content rising period in the electrolysis process was 92.2%.

In this embodiment, Q_{Product produced by birth}4410 kg; a is_{Flat plate}1.5 percent; the average value of the actual value of the raw material utilization rate of the chromium oxide in the rising period of the content of the chromium adopted by P is 92.2 percent; c is 99%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (2)_{Flat plate}105.92 kg.

2.3.2 according to the step 2.1, in the balance period of the chromium content, the feeding amount of the chromium oxide in unit hour is less than or equal to 60 kg; in the embodiment, the feeding amount of the chromium oxide is 105.92kg per day in the balance period, and the feeding operation needs to be completed within 2 hours;

2.3.3 when the measured value meets the requirement of the step 1, adding chromium oxide into the prebaked anode aluminum reduction cell according to the calculation results of the steps 2.3.1 and 2.3.2, wherein the starting time point of daily addition of the chromium oxide is after aluminum tapping of the aluminum reduction cell. The duration of the first chromium content equilibration period was 10 electrolysis days, followed by the start of the second aluminum chromium alloy electrolysis cycle.

In this example, the average of the actual values of the raw material utilization rates of the chromium oxides in the first chromium content rising period and the equilibrium period in the electrolysis process was 92.2%.

2.4 in the second chromium content rising period in the electrolysis process, in the electrolysis process that the mass percentage content of chromium in the aluminum stored in the aluminum electrolysis cell is from 1.5% to 2.8%, adding chromium oxide, detecting and analyzing that the content of chromium in the aluminum stored in the current electrolysis cell is 1.5%, the target content is 2.8%, and determining the daily rising rate of the chromium content to be 0.1%/day. The method comprises the following specific steps:

2.4.1 chromium content rise period, day 1 chromium oxide addition operation

2.4.1.1 calculation of the daily dosage of chromium oxide during the chromium content Up phase 1

In the day 1 calculation of the present embodiment, Q_Dish40200 kg; a is₁1.5% by spectral analysis; due to a₂-a₁When the ratio is 0.1%, a is determined₂1.6 percent; q_{Product produced by birth}4410 kg; p adopts a first chromium content rising period and a balance period in the electrolysis process, and the average value of the actual values of the raw material utilization rate of the chromium oxide is 92.2 percent; c is 98%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}177.35 kg.

2.4.1.2 according to step 2.1, in the chromium content rising period, the feeding amount of chromium oxide per hour is less than or equal to 60 kg; in the example, the feeding amount of chromium oxide on day 1 was 177.35kg, and the feeding operation required 3 hours to complete;

2.4.1.3 when the measured value meets the requirement of step 1, adding chromium oxide into the prebaked anode aluminum reduction cell according to the calculation results of step 2.4.1.1 and 2.4.1.2, wherein the starting time point of the daily addition of the chromium oxide is after aluminum tapping of the aluminum reduction cell.

After the feeding is finished on the 1 st day, the mass percent of chromium in the aluminum cell is actually 1.6% through the spectral analysis and detection, and the actual value of the utilization rate of the raw materials of the chromium oxide on the 1 st day is determined to be 92.2%.

And then calculating and feeding materials according to the method of the day 1 every day, wherein the specific process is not repeated until the mass percentage content of chromium in the aluminum in the memory amount of the aluminum electrolytic cell reaches 2.8 percent. In this example, the average value of the actual values of the raw material utilization rates of the chromium oxides in the first chromium content rising period and the equilibrium period and the second chromium content rising period in the electrolysis process was 92.2%.

2.5 when the mass percent of the chromium in the aluminum cell reaches 2.8 percent, starting feeding according to the balance period of the chromium content. During the first chromium content balancing period in the electrolysis process, chromium oxide is added, and the method specifically comprises the following steps:

2.5.1 calculate the daily charge of chromium oxide during the equilibrium period of the chromium content

wherein, W_{Flat plate}The daily charge (kg), Q, of chromium oxide in the equilibrium period of the chromium content_{Product produced by birth}The sunrise aluminum amount (kg) of the aluminum electrolytic cell, a_{Flat plate}The mass percentage content (%) of chromium in aluminum in the internal amount of the aluminum electrolytic cell in the balance period of the chromium content, P is the raw material utilization ratio (%) of chromium oxide, and C is the purity of the chromium oxide(%), m represents the mass percent content (%) of chromium in the chromium oxide.

In this embodiment, Q_{Product produced by birth}4410 kg; a is_{Flat plate}2.8 percent; p adopts the value obtained in the above accumulation process of 92.2%; c is 98%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (2)_{Flat plate}105.92 kg.

2.5.2 according to the step 2.1, in the balance period of the chromium content, the feeding amount of the chromium oxide in unit hour is less than or equal to 60 kg; in the embodiment, the feeding amount of chromium oxide per day in the equilibrium period is 105.92kg, and the feeding operation needs 2 hours to be completed;

2.5.3 when the measured value meets the requirement of the step 1, adding chromium oxide into the prebaked anode aluminum reduction cell according to the calculation results of the steps 2.5.1 and 2.5.2, wherein the starting time point of daily addition of the chromium oxide is after aluminum tapping of the aluminum reduction cell.

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 4410kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 2.8%; the mass percentage deviation of the chromium is less than 0.03 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 92.2 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.2 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

Example 8: a preparation method of aluminum-chromium alloy with 2.8 percent of chromium by mass percent is characterized in that an aluminum electrolytic cell is used for preparation, the electrolytic cell used in the embodiment is a prebaked anode aluminum electrolytic cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the electrolytic cell is a cradle type cell, and the series current of the electrolytic cell is 600 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The main technical conditions of the electrolytic cell are as follows: the average voltage was 3.625V and the electrolysis temperature was 915 ℃.

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃，nA constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 4.1 percent; CaF₂1.7 percent; MgF₂2.1 percent; LiF is 5.3%; AL₂O₃2.6 percent; the balance of cryolite nNaF. AlF₃N is 2.82, and the sum of the mass percentages of the components is 100 percent;

2.2.1 chromium content rise period, day 1 chromium oxide addition operation

2.2.2 chromium content rise period, day 2 chromium oxide addition operation

2.2.2.1 calculate the daily feed of chromium oxide during the chromium rise

2.2.3 chromium content rise period, day 3 chromium oxide addition operation

2.4 in the second chromium content rising period in the electrolysis process, in the electrolysis process that the mass percentage content of chromium in the aluminum stored in the aluminum electrolysis cell is from 1.5% to 2.8%, adding chromium oxide, detecting and analyzing that the content of chromium in the aluminum stored in the current electrolysis cell is 1.5%, the target content is 2.8%, and determining the daily rising rate of the chromium content to be 0.15%/day. The method comprises the following specific steps:

2.4.1 chromium content rise period, day 1 chromium oxide addition operation

In the day 1 calculation of the present embodiment, Q_Dish40200 kg; a is₁1.5% by spectral analysis; due to a₂-a₁0.15%, determine a₂1.65 percent; q_{Product produced by birth}4410 kg; p adopts a first chromium content rising period and a balance period in the electrolysis process, and the average value of the actual values of the raw material utilization rate of the chromium oxide is 92.2 percent; c is 98%; m is through Cr₂O₃Molecular formula, calculated as 68.42%; w is calculated by the formula (1)_{Lifting of wine}213.07 kg.

2.4.1.2 according to step 2.1, in the chromium content rising period, the feeding amount of chromium oxide per hour is less than or equal to 60 kg; in the example, the feeding amount of chromium oxide on day 1 was 177.35kg, and the feeding operation took 4 hours to complete;

After the feeding is finished on the 1 st day, the mass percent of chromium in the aluminum cell is actually 1.65% through the spectral analysis and detection, and the actual value of the utilization rate of the raw materials of the chromium oxide on the 1 st day is determined to be 92.2%.

Example 9: a preparation method of aluminum-chromium alloy with 2.8 percent of chromium by mass percent is characterized in that an aluminum electrolytic cell is used for preparation, the electrolytic cell used in the embodiment is a prebaked anode aluminum electrolytic cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the electrolytic cell is a cradle type cell, and the series current of the electrolytic cell is 600 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The main technical conditions of the electrolytic cell are as follows: the average voltage was 3.625V and the electrolysis temperature was 915 ℃.

The preparation method specifically comprises the following steps:

step 1: measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；AL₂O₃Wherein KF is 1.1 percent; CaF₂3.7 percent; MgF₂3.6 percent; LiF is 2.3%; AL₂O₃4.6 percent; the balance of cryolite nNaF. AlF₃N is 2.48, and the sum of the mass percent of the components is 100 percent;

the other steps were the same as in example 7.

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 4410kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 2.8%; the mass percentage deviation of the chromium is less than 0.03 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 92.2 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.3 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

Example 10: a preparation method of aluminum-chromium alloy with 2.8 percent of chromium by mass percent is characterized in that an aluminum electrolytic cell is used for preparation, the electrolytic cell used in the embodiment is a prebaked anode aluminum electrolytic cell, the adopted anode is a carbon anode, the cathode is a graphite cathode, the electrolytic cell is a cradle type cell, and the series current of the electrolytic cell is 600 KA; the chromium oxide in this example is Cr₂O₃The purity was 99%. The main technical conditions of the electrolytic cell are as follows: the average voltage was 3.771V, and the electrolysis temperature was 932 ℃.

The rest is the same as in example 7.

By using the aluminum-chromium alloy prepared by electrolysis in the embodiment, 4410kg of aluminum-chromium alloy can be produced in a single electrolytic cell every day, and the mass percentage of chromium in the aluminum-chromium alloy is 2.8%; the mass percentage deviation of the chromium is less than 0.03 percent, and the components are uniform; the average value of the actual values of the raw material utilization rate of the chromium oxide reaches 92.1 percent, and the raw material utilization rate is high; the current efficiency of the aluminum cell is 91.3 percent; in the production process of the aluminum-chromium alloy, the technical conditions of the main electrolysis process are basically kept unchanged, and the production process is stable and continuous.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The preparation method of the aluminum-chromium alloy is characterized by being prepared by an aluminum electrolytic cell and comprising the following steps: (1) measuring nNaF AlF in the electrolyte of an aluminum electrolysis cell in a producing aluminum electrolysis cell₃N is a constant of 2.1 to 2.9; KF; CaF₂；MgF₂；LiF；Al₂O₃Wherein the nNaF. AlF₃62 to 94 percent; KF is 0.1-8%; CaF₂1-8%; MgF₂1-8%; LiF accounts for 1-8%; al (Al)₂O₃2-7%, wherein the sum of the mass percentages of the components is 100%; (2) when the measured values are within the above ranges, chromium oxide is added and the technical conditions of the electrolytic process are detected and maintained: the electrolysis temperature is 900-960 ℃, and the average voltage is 3.5-4.3V, so as to obtain the aluminum-chromium alloy;

adding chromium oxide to the aluminum electrolysis cell according to the step (2), wherein the electrolysis process comprises at least one aluminum-chromium alloy electrolysis cycle, wherein the one aluminum-chromium alloy electrolysis cycle comprises: a chromium content rising period and a chromium content balancing period; wherein the chromium content rising period is an electrolysis process before the mass percent content of chromium in aluminum stored in the aluminum electrolysis cell reaches a set value, and the mass percent content of chromium in stored aluminum continuously rises at the stage; the chromium content balancing period is an electrolysis process after the mass percentage content of chromium in the aluminum stored in the aluminum electrolysis cell reaches a set value, and the mass percentage content of chromium in the stored aluminum is kept unchanged at the stage;

in the chromium content rising period in the electrolysis process, chromium oxide is added, and the specific steps comprise:

wherein, W_{Lifting of wine}The daily feeding amount of the chromium oxide in the chromium content rising period is kg; q_DishThe mass of the aluminum in the aluminum cell is kg; a is₁Is the actual detection value of the mass percent content of chromium in the aluminum cell memory on the same day,%; a is₂The content of chromium in the aluminum cell memory on the next day is the mass percent content expected to be reached; a is₂-a₁Daily rate of rise of chromium content,%; q_{Product produced by birth}The sunrise aluminum amount of the aluminum cell is kg; p is the raw material utilization of chromium oxide,%; c is the purity of chromium oxide,%; m is the mass percent content of chromium in the chromium oxide;

when the chromium content of the aluminum in the electrolytic cell is less than 1.5 percent by mass percentage, the daily lifting rate of the chromium content is less than or equal to 0.3 percent per day; when the chromium content of the aluminum stored in the electrolytic cell is more than or equal to 1.5% and less than 2.8%, the daily lifting rate of the chromium content is less than or equal to 0.15%/day.

2. The method of claim 1, wherein the chromium content is increased by an amount of chromium oxide addition per hour equal to or less than I/b; wherein, I is series current, kA; b is a constant satisfying: b =10 kA/kg.

3. The method of claim 1, wherein during the chromium content rise period in the electrolysis process, the addition time of chromium oxide is as follows:

the starting point of daily addition of chromium oxide is after the aluminium is tapped from the aluminium electrolysis cell.

4. The method for preparing aluminum-chromium alloy according to claim 1, wherein the chromium content of aluminum in the aluminum cell is controlled to be constant during the balance period of the chromium content, and the method comprises the following steps:

wherein, W_{Flat plate}Is the daily feeding amount of the chromium oxide in the balance period of the chromium content, kg; q_{Product produced by birth}The sunrise aluminum amount of the aluminum cell is kg; a is_{Flat plate}Is the mass percentage content of chromium in the aluminum cell memory in the balance period of chromium content,%; p is the raw material utilization of chromium oxide,%; c is the purity of chromium oxide,%; m is the mass percent content of chromium in the chromium oxide.

5. The method of claim 4, wherein the chromium content is balanced by an oxide addition of chromium per hour ≤ I/b; wherein, I is series current, kA; b is a constant satisfying: b =10 kA/kg.

6. The method for preparing an aluminum-chromium alloy as claimed in claim 4, wherein the chromium oxide is added during the balance period of chromium content in the electrolysis process for the following time:

7. A method of manufacturing an aluminium-chromium alloy according to any one of claims 1 to 6 wherein the chromium oxide is CrO₂，Cr₂O₃Either one or a combination of both.

8. The method as claimed in any one of claims 1 to 6, wherein the aluminum electrolytic cell is a pre-baked anode aluminum electrolytic cell.