CN101054687A - Method and device for measuring distance between cathode and anode of aluminum electrolysis bath - Google Patents

Abstract

A method for measuring the distance between the cathode and the anode of aluminum cell is used for determining the pole distance between two polars by determining the interface between the aluminum solution and the electrolyte and the position of anode bottom palm by measuring the abrupt change of voltage position between two electrode probe heads. The specifical operations adopts a pole clearance measurement mechanism. Said measurement mechanism comprises a test frame, a control housing, a lifting gearing and electrode probe heads, wherein said lifting gearing is mounted at the moveable trolley of the test frame, the control housing and the electrode probe heads are mounted at the test frame, and a monolithic computer used as the control housing core. Said monolithic computer is equipped with the control operation program therein and is connected respectively with the electrolytic tank anode, the electrode probe heads and the test lifting gearing through interface circuits and used for controlling the distance measuring process. Said invention possesses the advantages that it can be used for pole clearance measurement of industrial cell and excess voltage test quickly and conveniently, with more accurate measurement results.

Description

The measuring method of distance and device between a kind of aluminium electrolytic cell cathode and the anode

Technical field

The invention belongs to technical field of aluminum electrolysis, particularly a kind ofly be applied in the aluminium cell measuring method and the device of distance between the negative electrode and anode.

Background technology

At present, aluminium electrolytic industry adopts traditional Hall-Heroult method always.Used ionogen is sodium aluminum fluoride-alumina molten salt system, and anode and negative electrode are placed up and down, and anode is the prebake carbon anode, and negative electrode is the charcoal element, develops to graphitization cathode at present.During electrolysis, negative electrode aluminium liquid is deposited on the bottom of electrolyzer, and constantly the cumulative metal aluminium liquid becomes actual negative electrode, and the aluminum liquid horizontal height of general large-scale aluminum electrolytic cell reaches about 20cm.Because electrolytic process exists powerful electric field that aluminium liquid is stirred, make that the fluctuation of aluminium fluid level is bigger.And present pole span measuring method---pricker is inserted method, and this method adopts drill rod to insert in the melt, reintroduces to determine the position of aluminium liquid, and method is too determined the position of anode bottom then, determines pole span according to the distance of these two positions.It is relatively poor that pricker is inserted the accuracy of method, mainly be because ionogen and aluminium liquid interface be difficult to determine accurate, and personal errors very big due to.

Summary of the invention

Problem at prior art exists the invention provides a kind of method and device that is used to measure distance between aluminium electrolytic cell cathode and the anode.

We's ratio juris is as follows:

The pole span of aluminium cell refers to the upper surface of groove bottom aluminium liquid to the distance between the anode bottom.The key of accurately measuring pole span is accurately to measure position, the especially upper surface of aluminium liquid of these two faces.The upper surface of aluminium liquid changes in electrolytic process, also exists the factor of fluctuation simultaneously, and the position of therefore measuring aluminium liquid upper surface in the electrolyzer is relatively more difficult.

The inventive method is based on the specific conductivity difference of electrolytical specific conductivity and aluminium liquid at 10000 times, determines the upper surface of aluminium liquid with the Changing Pattern of the groove thorax degree of depth by measuring electromotive force.Promptly when probe rise in by aluminium liquid with electrolytical interface after, a flex point appears in the variation of electromotive force, the position of this flex point is exactly aluminium liquid and electrolytical interface.

The position of anode bottom also can be determined by the variation of current potential.Because anodic polarization voltage is bigger, therefore before probe touched the anode bottom, the current potential of measurement also comprised the anodic polarizing voltage, touched on the anode but work as probe one, the voltage of measuring has not just comprised polarizing voltage, therefore will occur a current potential flex point on anode bottom position yet.The position of these two points has determined that the measurement of the pole span of electrolyzer is just accurate.

Test set of the present invention comprises testing jig, measures controlling box, hoisting appliance and electrode probe, hoisting appliance is contained on the moveable carriage of testing jig, controlling box and electrode probe are contained on the testing jig, the controlling box core is a micro-chip, micro-chip has been embedded in the red-tape operati program, micro-chip links to each other with anode electrolytic cell, electrode probe and testing jig hoisting appliance respectively by interface circuit, and the control ranging process.

Concrete measuring method and process are as follows,

Operation control box 6 is sailed dolly 11 into specified location, and anode connection 5 is received on the anode, and probe 1 is put into a certain position S in the aluminium liquid 2 of bottom of electrolytic tank ₁, operation control box 6 is write down probe 1 automatically at S ₁Magnitude of voltage V during the position ₁, with the speed lifting probe 1 of per minute 1cm, at this moment the voltage on the current potential table is almost constant, when probe rises to aluminium liquid and electrolytical interface S then ₂The time, flex point appears in potential variation.Continuation is with the speed lifting probe of per minute 2cm-5cm, when popping one's head in 1 near anode bottom S ₃The time, magnitude of voltage is V ₂, slowing down lifting speed is per minute 0.2cm-1cm, when flex point appears in voltage, promptly arrives anode basal surface S ₃, magnitude of voltage is V ₃, can measure pole span d=S ₃-S ₂, can obtain anodic overvoltage η simultaneously _Anode=V ₃-V ₂Above magnitude of voltage, data such as shift value are gathered by the micro-chip in the controlling box 6, then by programming, according to the slope ratio of 2 lines of adjacent bright, find the S in the data point ₁, S ₂And S ₃And corresponding V ₁, V ₂And V ₃Automatically calculate pole span d and anodic overvoltage η _Anode

Advantage of the present invention is to be used for the measurement and the superpotential test of industrial cell pole span fast and easily.

Description of drawings

Fig. 1 is pole span measuring apparatus figure of the present invention;

Fig. 2 is a pole span measuring principle explanatory view of the present invention;

Fig. 3 is a platinum sonde configuration synoptic diagram in the embodiment of the invention;

Fig. 4 measures schema for pole span of the present invention.

Among the figure: 1, probe, 2, aluminium liquid, 3, anode; 4, anode rod, 5, anode connection, 6, controlling box; 7, screw mandrel, 8, removable silk braid, 9, strengthen the collar; 10, hoisting appliance, 11, moveable carriage, 12, dolly moves the transmission controlling box; 13, line, 14, stirrup, A1, platinized platinum; A2, sealed structure, A3, protective tube, A4, lead.

Embodiment

The device that the present invention measures the electrolyzer pole span is as shown in Figure 1:

Testing jig: be made up of moveable carriage 11, screw mandrel 7, removable silk braid 8, be used for fixing the system of installing and measuring and electrode lifting mechanism, the dolly bottom is equipped with movably wheel, is convenient to moving of equipment.

Electrode probe: as shown in Figure 3, be used for reaching the part of electrolyzer, there is a platinum probe front portion, is used for accurately measuring current potential.

Electrode probe material: A1 is a metal platinum; The sealed structure material of A2 is that boron nitride or high-temperature cement are made; A3 is an insulation protection tube, adopts boron nitride tube or alundum tube to make; A4 probe line adopts platinum filament or nichrome wire to make.

The hoisting appliance of electrode: present embodiment adopts the gear unit transmission, also can adopt hydrostatic transmission, and the automatic lifting anode is popped one's head in as required, and rising or falling speed is adjustable, and the position of electrode can accurately be measured.

Controlling box 6, controlling box contain micro-chip or programmable logic controller is formed, and has to calculate and realize function, and can move by output order control dolly, and its control survey program is got two adjacent coordinates (X in proper order from the start position of detecting area as shown in Figure 4 ₁, Y ₁), (X ₂, Y ₂), calculate the slope between these 2 ${\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="A20071001044300061.png,A20071001044300062.png"\; state="\{\{state\}\}">K</figure-callout>}}_1=\frac{Y_2-Y_1}{X_2-{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="A20071001044300061.png,A20071001044300062.png"\; state="\{\{state\}\}">X</figure-callout>}}_1},$ Preserve K ₁, in like manner, get (X ₂, Y ₂), (X ₃, Y ₃) 2 points, calculate ${\mathrm{<figure-callout\; id="2"\; label="K"\; filenames="A20071001044300061.png,A20071001044300062.png"\; state="\{\{state\}\}">K</figure-callout>}}_2=\frac{Y_3-Y_2}{X_3-{\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="A20071001044300061.png,A20071001044300062.png"\; state="\{\{state\}\}">X</figure-callout>}}_2},$ Preserve K ₂, according to said method, can preserve several slope datas K _iAt slope data K _iIn find K _iThe position of undergoing mutation can be judged to be point of inflexion on a curve.The implementation method of searching flex point is that counters design i when i=0, judges K ₁Whether equal 0, work as K ₁, judge K at=0 o'clock ₂Whether greater than K ₁, if, then can be according to K ₁, K ₂Be that slope between the coordinate at 2 at flex point place is fixed first corner position.If K ₂〉=K ₁, i=i+1 compares next group slope K so ₂And K ₃,, write down respective coordinate value afterwards up to finding out flex point.In like manner judge K _iIf equal ∞, can find second flex point.Corresponding aluminium liquid in the position of two flex points and electrolytical interface and present position, anode bottom.The difference of two positions is pole span.

Adopt apparatus of the present invention to measure, when carrying out large-scale experiment research in 3000A electrolytic trial groove, the electrolyte body that electrolysis is adopted is NaF-AlF ₃-4Al ₂O ₃-2CaF ₂(wt.%), NaF/AlF wherein ₃The ratio of amount of substance is 2.2.930 ℃ of electrolysis temperatures.

Adjust the position, after device connected, operation control box 6 was put into position S in the aluminium liquid of bottom of electrolytic tank with probe 1 ₁, this moment magnitude of voltage V ₁=2857mV, with the speed lifting probe 1 of per minute 0.8cm, at this moment the voltage on the current potential table becomes 2857mV hardly, when probe rises to aluminium liquid and electrolytical interface S then ₂The time (this moment in vertical direction, the displacement S of probe ₂-S ₁=12mm), flex point appears in potential variation.Continuation is with the speed lifting probe of per minute 5cm, when popping one's head in 1 soon near anode bottom S ₃The time, V ₂=671mV, slowing down lifting speed is per minute 0.2cm-1cm, when flex point appears in voltage, promptly arrives anode basal surface S ₃, magnitude of voltage is V ₃=204mV, the displacement of probe is pole span d=S ₃-S ₂=47mm can obtain anodic overvoltage η=V simultaneously ₃-V ₂=467mV.

Measured pole span d compares more accurate with superpotential η with adopting additive method.

Claims (3)

1, the measuring method of distance between a kind of aluminium electrolytic cell cathode and the anode is characterized in that determining aluminium liquid and electrolytical interface and anode bottom position by measuring two abrupt change of voltage positions between the electrode probe, thereby determines dipolar pole distance.

2, the measuring method of distance between aluminium electrolytic cell cathode and the anode according to claim 1 is characterized in that concrete operations are to adopt the pole span measuring apparatus, carry out according to the following steps:

(1) will install the controlling box line and be connected with anode electrolytic cell, probe places a certain position S of bottom of electrolytic tank aluminium liquid ₁, device record is automatically popped one's head at S ₁Magnitude of voltage V during the position ₁

(2) pop one's head in the speed lifting of per minute 1cm, when probe rises to aluminium liquid and electrolytical interface S ₂The time, flex point appears in potential variation;

(3) continue to pop one's head in, when popping one's head near anode bottom S with the speed lifting of per minute 2cm-5cm ₃The time, magnitude of voltage is V ₂

(4) slow down and lift speed,,, promptly arrive anode basal surface S when flex point appears in voltage with the lifting of per minute 0.2cm-1cm speed ₃, magnitude of voltage is V ₃

(5) calculate pole span d=S ₃-S ₂, anodic overvoltage η _Anode=V ₃-V ₂

3, distance measurement method equipment therefor between described aluminium electrolytic cell cathode of claim 1 and the anode, it is characterized in that this device comprises testing jig, controlling box, hoisting appliance and electrode probe, hoisting appliance is contained on the moveable carriage of testing jig, controlling box and electrode probe are contained on the testing jig, the controlling box core is a micro-chip, micro-chip has been embedded in the red-tape operati program, micro-chip links to each other with anode electrolytic cell, electrode probe and testing jig hoisting appliance respectively by interface circuit, and the control ranging process.

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