CN1873057A - Preparation method of lead electrobath for transitting to electrolysis in low termperature - Google Patents

Abstract

The invention relates to an aluminum electrolysis production technology, in particular to an aluminum electrolysis cell and a low-temperature electrolysis transition production method. The production method of the present invention comprises the following steps: a) adjusting the electrolyte composition to reduce the primary crystal temperature step; b) electrolytic cell setting voltage control step; c) electrolytic overheat control step; d) aluminum level control step; e) intelligent fuzzy parameter control step ; f) Fine operation steps. The present invention has the following beneficial effects: the method of the present invention improves the production conditions of the electrolytic cell, keeps the primary crystal temperature of the electrolytic cell in a lower range (905°C-915°C) all the time, and enables electrolytic production to be carried out at an electrolytic temperature of 915°C-930°C work, the current efficiency of the electrolytic cell is improved, and the power consumption is reduced; the invention is suitable for the transition from aluminum electrolytic cells to low-temperature electrolytic production, and can also be applied to the transformation of electrolytic cells in other industries to low-temperature production.

Description

Production method for the transition from aluminum electrolytic cell to low-temperature electrolysis

Technical field

The invention relates to an aluminum electrolysis production technology, in particular to a production method for the transition from an aluminum electrolysis cell to low-temperature electrolysis.

Background technique

The electrolysis temperature of electrolytic cells in my country is generally between 950°C and 970°C, the molecular ratio of electrolytes is between 2.5 and 2.7, the current efficiency of electrolytic cells is about 92%, and the unit consumption of primary aluminum direct current is relatively high. The existing aluminum electrolysis with high electrolysis temperature has the following disadvantages: 1. The relatively high electrolysis temperature reduces the current efficiency of the electrolysis cell, and the unit consumption of DC power is high; 2. The material volatilization loss of the electrolysis cell is large, and the unit consumption of electrolysis production materials High; 3. The electrolysis temperature is high, and the material volatilization loss is relatively large, which affects the working environment of the workers in the electrolysis plant and brings harm to the health of the electrolysis workers. In today's fierce competition in the aluminum industry, it is particularly important to save energy, reduce losses, and improve current efficiency. At present, the technology of aluminum electrolysis at low temperature, which controls the electrolysis temperature at 915°C to 930°C, has not been recorded yet.

Contents of the invention

The problem to be solved by the present invention is to provide a production method for the transition from an aluminum electrolytic cell to low-temperature electrolysis, which improves the current efficiency of the electrolytic cell, reduces the unit consumption of DC power, and reduces the loss of material volatilization.

The production method of the aluminum electrolytic cell of the present invention transitions to the low-temperature electrolysis is realized through the following technical scheme: the production method of the present invention comprises the following steps:

a) adjusting the electrolyte composition to reduce the primary crystal temperature step; b) electrolytic cell setting voltage control step; c) electrolytic overheat control step; d) aluminum level control step; e) intelligent fuzzy parameter control step; f) fine operation step.

Compared with the prior art, the production method of the aluminum electrolytic cell of the present invention transitioning to low-temperature electrolysis has the following beneficial effects: because the present invention adopts the adjustment of the electrolyte composition to reduce the primary crystal temperature as the main method, the production conditions of the electrolytic cell are improved, and the primary crystal temperature of the electrolytic cell is improved. It is always in the lower range (905°C ~ 915°C), so that electrolytic production can work at an electrolysis temperature of 915°C ~ 930°C, which improves the current efficiency of the electrolytic cell and reduces power consumption; increasing the aluminum level can make the electrolytic cell The heat dissipates quickly, which plays a role in regulating the electrolysis temperature. At the same time, the higher aluminum level can also weaken the interaction force between the horizontal and vertical magnetic fields, so that the aluminum liquid remains stable. At the same time, the higher aluminum level can reduce the material. The volatilization loss reduces the cost of electrolytic production; the application of the intelligent fuzzy control technology of the present invention improves the advanced nature of electrolytic aluminum production; the reduction of volatilization of materials also improves the working environment of workers correspondingly. The invention is suitable for the transition of aluminum electrolytic cells to low-temperature electrolytic production, and can also be applied to the transformation of electrolytic cells in other industries to low-temperature production.

Detailed ways

The technical scheme of the production method for the transition from the aluminum electrolytic cell to the low-temperature electrolytic production of the present invention will be further described below in conjunction with the examples.

Example 1.

The production method of aluminum electrolytic cell of the present invention transitions to low-temperature electrolysis comprises the following steps:

a) Steps of adjusting the electrolyte composition to reduce the primary crystallization temperature Control the molecular ratio, CaF ₂ , MgF ₂ , and LiF in the ranges of 2.2-2.35, 3-6%, 1-4%, and 1.6-2.0% respectively to make the primary crystallization temperature of the electrolytic cell In the reduced range, the primary crystal temperature is 905 ° C ~ 915 ° C; the molecular ratio refers to the molar ratio of sodium fluoride and aluminum fluoride, and the adjustment of the electrolyte composition to reduce the primary crystal temperature refers to Add aluminum fluoride to the electrolytic cell, and add calcium fluoride and magnesium fluoride for control. The amount of aluminum fluoride added is 13kg/batch, and the amount of aluminum fluoride added is adjusted according to the molecular ratio. Generally, the batch of aluminum fluoride added 0-8 batches/day.

b) The set voltage control step of the electrolytic cell is used to control the set voltage of the cell below 4.10V; the set voltage control of the electrolytic cell refers to the intelligent fuzzy control of the computer, according to the relationship between the molecular ratio and the set voltage , that is, every time the molecular ratio decreases by 0.1, the set voltage of the tank increases by about 0.04-0.05V, and the set voltage parameters of the upper computer of the computer station are adjusted, and transmitted to the tank control machine to control the set voltage.

c) Control the aluminum level by adjusting the aluminum output of the electrolytic cell. When the aluminum level is too high, appropriately increase the aluminum output; when the aluminum level is too low, appropriately reduce the aluminum output, and maintain the aluminum level by adjusting the output of aluminum liquid The height is between 20cm and 23cm; by adjusting the aluminum level and setting the voltage, the superheat of the electrolytic cell can be controlled at about 15°C;

d) The intelligent fuzzy parameter control step is used to set the blanking interval, effect waiting period, under cycle time, excessive cycle time, anode moving time and blanking initialization time, and control the alumina concentration at 1.5% to 3.5% within a narrow range;

e) Fine operation steps are used to ensure the efficient operation of the electrolyzer at a lower temperature through the quality of employee operation and intelligent fuzzy control.

The intelligent fuzzy control system refers to an intelligent fuzzy expert control system.

The fine operation method described refers to

a) The aluminum level is controlled at 16-18cm in the first month; the electrolyte level is not lower than 25cm in the first month; the molecular ratio of the new slot is not lower than 2.8, not lower than 2.5 in the second month, and not lower in the third month In 2.3; Add about 60 tons of fresh alumina in the first month of new slotting, and add about 60 tons of fluorine-loaded alumina in the second month; but do not add aluminum fluoride;

b) During the anode exchange operation, the sediment at the bottom of the furnace should be treated, and the shelling head of the crane should be 10cm away from the pressure iron during large surface processing;

c) When adding anode insulation material, first block the anode seam and the steel claw inside the new pole with a material block with a particle size of ≤5cm, then bury two-thirds of the steel claw with alumina fabric, and leave 10cm of the weight iron;

d) Regularly maintain the fixed container of the shelling and feeding system;

f) timely salvage the carbon residue suspended in the electrolyte solution;

g) By adding cryolite or electrolyte blocks on site, the electrolyte level is controlled at 20-23cm, so that the amount of electrolyte flux is increased and the probability of alumina precipitation is reduced;

h) Increase the thickness of the anode and the large surface covering material from the original 2 to 3 cm to the current 3 to 5 cm;

i) Adjust the level and molecular ratio of the electrolyte aluminum liquid according to the height of the tank temperature. When the electrolysis temperature is higher than 930°C, appropriately reduce the molecular ratio, increase the aluminum level, and reduce the electrolyte level; when the electrolysis temperature is lower than 915°C, appropriately Increase molecular ratio, reduce aluminum level, increase electrolyte level.

Claims (6)

1. A production method for the transition of an aluminum electrolytic cell to low-temperature electrolysis, characterized in that the production method comprises the following steps: a) Steps of adjusting the electrolyte composition to lower the primary crystallization temperature Control the molecular ratio, CaF ₂ , MgF ₂ , and LiF in the ranges of 2.2-2.35, 3-6%, 1-4%, and 1.6-2.0% respectively to make the primary crystallization temperature of the electrolytic cell In the reduced range, the primary crystal temperature is 905 ° C ~ 915 ° C; b) The set voltage control step of the electrolytic cell is used to control the set voltage of the cell below 4.10V; c) The electrolytic overheating control step is used to control the superheating of the electrolytic cell at about 15°C; d) The aluminum level control step is used to control the aluminum level of the electrolytic cell between 20 and 23 cm; e) Intelligent fuzzy parameter control step is used to set the blanking interval, effect waiting period, under cycle time, excessive cycle time, anode moving time and blanking initialization time, and control the alumina concentration at 1.5% to 3.5% within a narrow range; f) Fine operation steps are used to ensure the efficient operation of the electrolytic cell at a lower temperature through the quality of employee operation and intelligent fuzzy control. 2. The production method for the transition from an aluminum electrolytic cell to low-temperature electrolysis according to claim 1, characterized in that the step of adjusting the electrolyte composition to lower the primary crystal temperature refers to adding aluminum fluoride to the electrolytic cell through a dense-phase conveying system, adding Calcium fluoride and magnesium fluoride are controlled, and the amount of aluminum fluoride added is 13kg/batch. Generally, the batch of aluminum fluoride added is 0-8 batches/day. 3. The production method for the transition from aluminum electrolytic cell to low-temperature electrolysis according to claim 1, characterized in that the step of controlling the set voltage of the electrolytic cell refers to controlling the electrolytic cell through computer intelligent fuzzy control and parameter adjustment of the upper computer the set voltage. 4. The production method for the transition from aluminum electrolytic cell to low-temperature electrolysis according to claim 1, characterized in that the aluminum level control step refers to keeping the aluminum level between 20cm and 23cm by adjusting the amount of aluminum liquid drawn out. 5. The production method for the transition from aluminum electrolytic cell to low-temperature electrolysis according to claim 1, characterized in that said intelligent fuzzy control system refers to an intelligent fuzzy expert control system. 6. The production method for the transition from aluminum electrolytic cell to low-temperature electrolysis according to claim 1, characterized in that the fine operation method for adjustment refers to a) The aluminum level is controlled at 16-18cm in the first month; the electrolyte level is not lower than 25cm in the first month; Not lower than 2.5, and not lower than 2.3 in the third month; fresh alumina is added in the first month of new slotting, and fluorine-loaded alumina is added in the second month; b) During the anode exchange operation, the sediment at the bottom of the furnace should be treated, and the shelling head of the crane should be 10cm away from the pressure iron during large surface processing; c) When adding anode insulation material, first block the anode seam and the inner steel claw of the new pole with a material block with a particle size of ≤10cm, then bury two-thirds of the steel claw with alumina fabric, and leave 10cm of the weight iron; d) Regularly maintain the fixed container of the shelling and feeding system; f) timely salvage the carbon residue suspended in the aluminum solution; g) By adding cryolite or electrolyte blocks on site, the electrolyte level is controlled at 20-23cm, so that the amount of electrolyte flux is increased and the probability of alumina precipitation is reduced; h) Increase the thickness of the anode and the large surface covering material from the original 2 to 3 cm to the current 3 to 5 cm; i) Adjust the level and molecular ratio of the electrolyte aluminum liquid according to the height of the tank temperature. When the electrolysis temperature is higher than 930°C, appropriately reduce the molecular ratio, increase the aluminum level, and reduce the electrolyte level; when the electrolysis temperature is lower than 915°C, appropriately Increase molecular ratio, reduce aluminum level, increase electrolyte level.