Cathode shell of aluminium electrolysis unit
SUBSTANCE: cathode shell comprises longitudinal and end walls with vertical reinforcement ribs, a bottom, frames, which cover the walls and bottom and flanged sheet. Flanged sheet is fixed rigidly to intermediate ribs installed between frames at longitudinal walls of the shell by means of detachable joints through horizontal pads. The intermediate ribs are made of sheet metal with thickness from 0.3 up to 1 time of the shell wall thickness.
EFFECT: longer service life of the electrolysis unit.
3 cl, 2 dwg
The invention relates to the metallurgy of non-ferrous metals and can be used in the design of the cathode casing of the electrolytic cell for obtaining aluminium electrolytic method.
The cathode casing is one of the elements aluminum cell and is used to protect the prisoner inside lining from the destructive actions of efforts that occur in the process of the aluminum electrolysis cell. In this regard, he must have the necessary strength, as the strength of the casing to a greater extent depends on the lifetime of the cell. In addition, the cathode casing must provide heat removal, which contributes to the formation of a protective crust and nastily. The skull and nastily allow to intensify the work of the cell, prevent the destruction of the lining and increase the service life of the cell. The above is of great importance for electrolytic great power.
Known cathode casing aluminum cell samotnoho type, which contains longitudinal and end walls with vertical stiffeners and frames, plate and flange plate (Sushkov, A. I. and other metals, 1965, pages 318-321, Fig.113 d, 114).
The disadvantage of analog is the connection flange of the sheet with the frames by welding. Flanged sheet should be cut when the overhaul, there be welded during installation of the lining, resulting in increased labor costs.
For the prototype accepted cathode casing aluminum cell, comprising a bottom, end walls with vertical stiffeners, longitudinal walls, the frames on longitudinal sides of the flange and the sheet rigidly connected with the ribs and frames with screw connections (RF Patent No. 2121527, m CL SS 3/08, 1998).
A disadvantage of the known cathode casing is that the longitudinal wall between the frames are not associated with a flanged sheet and not have stiffeners, as well as thermal deformation of the flange of the sheet put additional pressure on the ribs. Since the flange sheet is attached to the frames and is not associated with the walls of the cathode casing in between the frames, they are deformed under the action of pressure of the lining and high temperatures. Deformation of the walls leads to the uncovering of printed seams bottoms and integrity of the side lining and, consequently, to reduced service life of the electrolytic cell, and a significant effort at correcting the deformation of the walls in the repair of the cathode shell.
The objective of the invention is to increase the service life of the cell, reducing labor costs.
The technical result is to reduce the mechanical and thermal deformations of the longitudinal walls of the cathode casing is in between the frames and ribs.
The technical result is achieved in that the cathode casing aluminum cell, comprising longitudinal and end walls with vertical stiffeners and frames, the bottom flange and the sheet according to the present invention, the flanged sheet is rigidly connected to the intermediate ribs, vertically mounted between the frames, the longitudinal walls of the casing.
Flanged sheet can be connected with the intermediate ribs with screw connection, through the horizontal platform.
Intermediate ribs may be made of sheet metal with a thickness from 0.3 to 1 wall thickness of the shell.
In the inventive design of the cathode casing flange sheet is not associated with the frames. Flanged sheet casing is rigidly connected by means of detachable connections with intermediate ribs with a thickness from 0.3 to 1 wall thickness of the casing, a vertically mounted on the longitudinal walls in between the frames. In addition, the intermediate ribs are additional ribs and function as cooling fins. The range from 0.3 to 1 based on the fact that the choice of thickness less than the lower limit impractical because of the low reliability of the structure, and the upper limit is not economically justified, since a further increase in thickness does not increase the carrier is capable of being the STI.
The inventive design of the cathode casing allows to provide the necessary longitudinal rigidity of the walls in between the frames and eliminate the negative influence of thermal deformation of the flange of the node on the frames due to the mounting flange of the sheet to the intermediate ribs mounted between the frames, and by reducing the wall temperature, since the positioning of the intermediate ribs contributes to the intensification of heat.
The invention is illustrated by drawings, where Fig.1 shows a portion of the longitudinal wall of the cathode casing of Fig.2 - section a-a illustrating the image in Fig.1.
The cathode casing aluminum electrolysis cell consists of 1 longitudinal and end walls, the bottom (in the drawings are not marked), 2 frames. End walls are vertical ribs (the drawings are not marked). To the longitudinal wall 1 between the frames 2 are welded intermediate ribs 3, provided with horizontal platforms with 4 holes. The upper part of the cathode casing around the perimeter provided with a flanged sheet 5, which with the help of detachable joints 6 is rigidly connected with the intermediate ribs 3 through a horizontal platform 4.
Implementation of the present invention will reduce the deformation of the longitudinal walls of the cathode casing through the connection flange of the sheet with the longitudinal walls at about the agudah between the frames, and will also improve the cooling of the walls of the casing, which will have a positive effect on the service life of the cathode casing and the cell as a whole.
1. The cathode casing aluminum cell that contains the longitudinal and end walls with vertical ribs, the bottom, the frames that cover the walls and the bottom, and the flange sheet, characterized in that the longitudinal walls of the casing between the frames vertically mounted intermediate ribs rigidly connected to the flange plate.
2. The cathode casing under item 1, characterized in that the intermediate ribs are connected with the flange plate, by means of plug connections, through the horizontal platform.
3. The cathode casing under item 1, characterized in that the intermediate ribs are made of sheet metal, the thickness of which ranges from 0.3 to 1 wall thickness of the casing.
SUBSTANCE: invention relates to a cathode pack for an aluminium electrolytic cell. The cathode pack comprises a layer of composite containing graphite and solid material such TiB2, present with single mode granulometric composition, while d50 amounts to 10 - 20 mcm, in particular to 12 - 18 mcm, preferably to 14 - 16 mcm. Method for the production of a cathode pack with the said characteristics is described as well.
EFFECT: improved wear resistance of a cathode pack and simple manufacturing.
16 cl, 1 dwg
SUBSTANCE: cathode's top is turned towards the electrolytic bath, and the bottom has contacts for current input. Top and bottom parts, at least, on some sections are connected to each other in disconnectable manner using the protective interlayer.
EFFECT: lowering of the cathode cost and optimisation of the cathode operation.
10 cl, 5 dwg
SUBSTANCE: partitions and/or grids, and/or aluminium-moistened open-pore cellular structures from material lass electrically conductive than aluminium are placed under each anode on the bottom surface, perpendicular and/or at angle 45-90° to bottom plane, perpendicular and/or at angle 45-90° to longitudinal axis of cathode rods, which completely of partially prevent horizontal components of cathode current from flowing in aluminium layer.
EFFECT: reduction of horizontal components of currents in melt layer, uniform distribution of current, reduction of inter-pole distance and reduction of electric energy consumption for aluminium production or increase of output by current.
15 cl, 8 dwg
SUBSTANCE: method involves immersing mounted samples of silicon carbide blocks into an electrolyte at aluminium electrolysis temperature and bubbling the electrolyte with carbon dioxide, air or a mixture thereof, moving the samples and comparing the obtained samples with the original samples. After immersion, the samples are held in the electrolyte which is in contact with aluminium at electrolysis temperature, with the controlled area of the sample in the electrolyte. The samples are then raised and held with the controlled area of the sample in a gas phase for not more than 20 minutes. The samples are then moved in the vertical plane while alternately holding the controlled area in the electrolyte and in the gas phase for not more than 10 minutes and the degree of wear thereof is determined from change in the volume of the samples.
EFFECT: shorter time for testing samples of blocks and obtaining visible reduction in cross dimensions of samples of said blocks owing to intensification of the wear process by increasing the rate of wear.
3 cl, 3 dwg, 2 ex, 2 tbl
SUBSTANCE: method involves introduction of carbon-bearing substrate material to a mould and application onto it of a layer of composite heat-resistant material containing metal boride, sealing of the contents of the mould in the form of a cathode block and annealing of the cathode block; as material of carbon-bearing substrate and the layer of composite heat-resistant material there used are materials having close coefficients of thermal linear expansion and values of sodium expansion and the following particle size distribution: content of fractions in carbon-bearing substrate (-10+0.071) mm - 76±10 wt % and (-0.071+0) mm - 24±10 wt %, content of fractions in the layer of composite heat-resistant material (-10+0.071) mm - 50±30 wt % and (-0.071+0) mm - 30±50 wt %; with that, material of the carbon-bearing substrate is added to a mould pre-heated to the material temperature. The composite heat-resistant material layer in a sealed state is maximum 8.0% of height of the cathode block and contains 20.0-80.0 wt % of metal diboride. Sealing of the cathode block is performed by vibration moulding, and annealing is performed at 1100°C during 5 hours.
EFFECT: improving quality and service life.
3 cl, 3 dwg, 1 tbl
SUBSTANCE: invention relates to a design of a cathode section of an aluminium electrolyser. The cathode section includes a cathode carbon unit, a cathode current-carrying rod with an electrically conducting part from material with high specific electric conductivity, which is installed in an internal cavity of the cathode carbon unit and fixed in it by means of a cast iron cast. The electrically conducting part of the rod is made in the form of an insert of individual elements attached to each other with a gap, which is installed on one or more outer surfaces of the cathode current-carrying rod through a cast iron casting layer. The individual elements of the insert can be of round or rectangular shape or any other type of cross section. Inserts can be installed throughout the length from 10% to 100% of length of the cathode current-carrying rod.
EFFECT: reduction of voltage drop in a cathode unit and low electric contact resistance between a cathode current-carrying rod and an electrically conducting insert with high specific electric conductivity throughout the length of the cathode current-carrying rod.
3 cl, 3 dwg
SUBSTANCE: on hearth surface placed are baffles and/or grates, and/or open-pore cellular structures wetted by aluminium made of material with lower electric conductivity compared with that of aluminium perpendicular and/or at 45°-90° to heart surface, perpendicular and/or at 45°-90° to lengthwise axis of cathode rods preventing partially or completely the flow of horizontal components of cathode currents in aluminium layer along the hearth. Electrolytic cell can operate with consumable or nonconsumable anodes, that is, "inert" anodes.
EFFECT: uniform current distribution, smaller electrode gap, lower power consumption, higher yield.
15 cl, 5 dwg
SUBSTANCE: electrolysis unit includes a cathode device containing a bath provided with a coal bottom and composed of coal blocks enclosed in a metal housing, with refractory and heat-insulating materials arranged between the metal housing, an anode assembly containing coal anodes connected to anode sludge, arranged in upper part of the bath and submerged into molten electrolyte; at the coal bottom, under each of the anodes there located are floats with higher specific electric conductivity in comparison to that of electrolyte, stable to destruction in cryolite-alumina melts and liquid aluminium; with that, upper surface of the float projects above the level of cathode aluminium and the floats can be moved and/or replaced to reduce inter-pole gap between anode and cathode. The floats are made from carbon, or from silicon carbide, or from a mixture of titanium diboride and carbon based on high-temperature binding substance and are covered with titanium diboride. Upper surface of the float is flat, or convex, or concave, or inclined to horizon and has capillaries and/or channels, and/or planes attaching the upper surface of a pedestal to cathode metal.
EFFECT: reduction of specific power consumption.
15 cl, 4 dwg
SUBSTANCE: composite has composition defined by formula (C-N-B-MR)x(Al-MR)y(R)z, where MR is one or several carbides, nitrides or borides of one or more heat-resiatant metals of IV, V, VI groups, C-N-B-MR is one or several carbides, nitrides or borides of one or more heat-resistant metals of IV, V or VI groups, Al-MR is one or several aluminides of one or several aforesaid heat-resistant metals. Note here that if MR=Nb, Ta, Hf, Zr, Ti, V, then Al-MR=Al3MR; is MR-W, Cr, then Al-MR=Al4MR; if MR=Mo, then Al-MR=Al8Mo3 or Al17Mo4. Note here that the condition should be satisfied whereat if C-N-B-MR=TiB2, Al-MR is not Al3Ti; R is residual component other than carbon containing one or several phases from Al4C3, AlN, AlB2, Al1·67B22, MRtAlu(C-N-B)v, where t, u, v are numbers larger than or equl to zeto; x, y, z are volume fractions of appropriate components. Note here that x>y; x+y>0.5; x+y+z=1 and 0.01<y<0.5.
EFFECT: composite features good wettability due to decreased grain size and higher density of interface surface to allow using said composite as coating of components wetted by liquid aluminium.
12 cl, 15 dwg
SUBSTANCE: proposed cathode comprises jacket and lining with base made of heat-insulation and refractory materials, side lining, bottom of hearth sections with cathode rods and cathode downleads. The latter are made from the stack of flexible aluminium tapes, contact plate and steel adapter to be welded as-assembled to cathode rod and plugged to cathode bus. Cathode downleads are assembled in installing the lining by welding them to cathode rods and bolting downlead contact plates to the bracket. After disassembly of side lining, cathode rods with their downleads are extracted from cathode jacket, cleaned and transferred to cutting bay. Cutting is performed along the line or in zone of joint between rod and downlead metal adapter. After skinning the metal adapter end, cathode downlead is transferred for reassembly.
EFFECT: higher reliability due to larger number of aluminium tapes.
2 cl, 1 dwg
FIELD: metallurgy; graphitic cathodes for production of aluminum.
SUBSTANCE: the invention presents a graphitic cathode for electrolysis of aluminum and is dealt with the field of metallurgy, in particular, with the graphitic cathodes used in production of aluminum by an electrolysis. The graphitic cathode for electrolysis of the aluminum is produced by graphitization of the cathodic block from a carbonaceous material. At that the cathode is made as the entire block with different specific electrical resistance along its longitudinal axis. At that the specific electrical resistance in the end areas of the cathode is more, than in its central area. The technical result - increased service life of the graphitic cathode at the expense of increased erosion resistance in the end areas of the cathode.
EFFECT: the invention ensures increased service life of the graphitic cathode at the expense of increased erosion resistance in the end areas of the cathode.
6 cl, 7 dwg, 1 tbl
FIELD: metallurgy; production of graphitic cathodes.
SUBSTANCE: the invention presents an impregnated graphitic cathode for production of aluminum by electrolysis and is pertinent to the field of metallurgy, in particular, to production of the graphitic cathodes used in production of aluminum by electrolysis. The invention offers an impregnated graphitic cathode for electrolysis of aluminum and a method of its production. The cathode contains in its pores an impregnating product heat-treated. At that in the capacity of the impregnating product the cathode contains a carboniferous product heat treated under the temperature of no less than 1600°С to provide resistance to erosion at the expense of protection by the formed graphitized binding substance. The method includes production of the graphitic cathode, its impregnation by dipping into the impregnating product in vacuum and a thermal treatment. At that the graphitic cathode is produced from coke, with graphite or without it, and also from a pitch, and before impregnation it is exposed to calcination at the temperature exceeding 2400 °С. The impregnation is realized by a carboniferous product at the temperature of its viscous state and the thermal treatment of the impregnated cathode is conducted at the temperature of less than 1600 °С, but sufficient for hardening and-or sintering of the impregnating product and formation of the non-graphitized coal layer for protection of graphitizing binding substance against erosion. The technical result is an increase of service life of the graphitic cathode.
EFFECT: the invention ensures an increase of service life of the graphitic cathode.
4 cl, 2 dwg, 1 ex
FIELD: nonferrous metallurgy; production of aluminum by electrolysis of fused salts.
SUBSTANCE: the invention I pertinent to nonferrous metallurgy and may be used in a design of electrolyzers for production of aluminum by electrolysis of fused salts. The technical result of the invention is hardening of a hearth, a decrease of thickness of a metal layer on the hearth and an interpolar space, a decrease of speeds of circulatory flows of cathodic metal, a decrease of losses of current. The cathodic device contains a lined cathodic housing and a hearth made out of from carbonaceous blocks with channels of a rectangular cross section. On the surface of the hearth there is a wetted with aluminum cover and the channels have the length equal to the width of the stack of the cathodic device, and with a width equal 1,1-2,2 well of the carbonaceous block, depth, equal to 0.2-0.4 of height of the carbonaceous block and thy are formed by the lateral longitudinal surfaces of the carbonaceous blocks and the carbonaceous blocks of the lateral cathodic lining. The electro-conductive cover wetted with aluminum is made out of titanium diboride.
EFFECT: hardening of a hearth, a decrease of thickness of a metal layer on the hearth and an interpolar space, a decrease of speeds of circulatory flows of cathodic metal, a decrease of losses of current.
2 cl, 2 dwg
FIELD: major repair of aluminum cells.
SUBSTANCE: cathode casing of aluminum cell includes lengthwise walls with windows for outlet of cathode rods, end walls, bottom and ring frames rigidly joined with walls and bottom. In order to lower labor consumption, simplify mounting and dismounting operations. Ring frames adjacent at least to one of lengthwise walls (except boundary ring frames) from their upper part till inner edge in range of height of windows for outlet of cathode rods are freely adjoined to said lengthwise wall. According to other variant of invention at least one lengthwise wall is detachable. Parting places of said wall are arranged between boundary ring frames in range of height of windows for outlet of cathode rods. In parting places members providing rigid joint of detachable wall with fixed portion of casing wall are mounted.
EFFECT: improved design, simplified works at major repair.
FIELD: formation of protective coatings for carbon containing components of electrolytic cell at aluminum production.
SUBSTANCE: method comprises steps of preparing liquid suspension of refractory material dispersed in solution of lignosulfonate binder; applying suspension as coating on surface of carbon containing component; drying coating.
EFFECT: improved resistance of carbon containing component against rupture at operation of electrolysis cell.
34 cl, 1 dwg, 4 tbl, 7 ex
FIELD: non-ferrous metallurgy; electrolytic production of aluminum; cathode units of aluminum electrolyzers.
SUBSTANCE: proposed side lining includes interconnected members - plates and blocks made from non-metallic refractory compounds possessing high resistance and interconnected by means of end faces in form of inversed symmetrical projections and recesses and adhesive or cementing mix. Plates and blocks are made from silicon carbide. Angular blocks are made in form of strip, 70 mm thick and 600-800 mm long which is bent at center around longitudinal axis at angle of 90° relative to vertical whose end faces are inclined at angle of 18° relative to vertical and are narrowing downward by 219 mm each. End faces are made in form of inversed symmetrical projections and recesses at radius of 14-15 mm which are parallel to vertical axis of walls of aluminum electrolyzer.
EFFECT: increased service life; enhanced strength and reliability; saving of lining material; increased useful volume of electrolyzer; increased yield of aluminum.
FIELD: aluminum cells, namely cathode facing for them.
SUBSTANCE: cathode facing includes carbon blocks, heat insulation layer and refractory part having two protection layers, upper layer adjoining to carbon blocks and lower layer made of powder materials. Upper protection layer includes alumosilicate composition resistant against action of electrolyte components containing 27 -35% of Al2 O3 with fraction size no more than 2.5 mm and with thickness consisting 10 - 50% of height of refractory part. Lower protection layer is made at least of one sealed metallic vessel filled with refractory material including carbon-containing composition resistant against action of melt aluminum and electrolyte components and having heat conductivity factor no more than 0.1 Wt/(mK). In lower protection layer vessels are filled with carbon black; thickness of said layer consists 50 - 90% of height of refractory part.
EFFECT: increased useful life period, improved operational characteristics of cell.
3 cl, 7 dwg, 1 tbl
FIELD: aluminum production electrolyzers of all types.
SUBSTANCE: proposed method includes mounting the heat-insulating and refractory components of electrolyzer and applying protective material on base of covalent nitrides to surface of side lining. Used as protective material is boron nitride-based material which ensures reduction of after-start period, increases electrolyzer service life, enhances aluminum grade, increases yield by current and daily productivity of electrolyzer; protective material is applied flush with top in continuous layer. Lower boundary of coat is located below "electrolyte-metal" interface. Thickness of coat is maintained within 0.1-1 mm. Open surface porosity is maintained within 2-3%. Consistency of material of coat changes from fluid to viscous-flow state. Application of coat is performed by spraying, painting or concrete-spraying method.
EFFECT: increased service life of electrolyzer; increased daily productivity of electrolyzer.
4 cl, 2 dwg, 1 tbl
FIELD: installation of aluminum electrolyzer hearth.
SUBSTANCE: proposed method includes preliminary estimation of quality of hearth modules by proximate ultrasonic inspection, mounting of complete set of hearth modules and forming of hearth; electrolyzer is equipped with hearth modules at inhomogeneity index not exceeding 0.65 relative units according to ultrasonic inspection; inhomogeneity index is determined by the following formula Iinhom = (tmax/tmin-1), where Iinhom is inhomogeneity index according to ultrasonic inspection; tmax is maximum magnitude of index of ultrasonic inspection for definite electrolyzer; tmin is minimum magnitude of index of ultrasonic inspection for definite electrolyzer; hearth is formed in such way that adjacent modules with close indices of ultrasonic inspection are mounted in longitudinal and transversal directions; modules with minimum indices of ultrasonic inspection are mounted in center of hearth at smooth increase of this index toward end faces of electrolysis bath.
EFFECT: increased service life of hearth; reduced yield of low-grade metal; reduced power requirements.
3 dwg, 1 ex
FIELD: mounting aluminum electrolyzers at major repair or in capital construction.
SUBSTANCE: current-supply metal rod is placed in slot of carbon block on layer of carbon-containing conducting material. Surface of carbon block slot is preliminarily coated with carbon-based surfactant and layer of carbon-containing conducting material is compacted by vibration applied on current-supply metal rod, thus ensuring reliable electromechanical "conducting rod-carbon block" contact and reducing probability of penetration of aluminum melt into hearth body. At application of vibration in local zone on side of flush area, maximum reduction of voltage drop is ensured in contact layer between rod and block slot. Maximum thickness of layer of carbon-containing conducting material before vibration is equal to optimal magnitude determined by definite formula.
EFFECT: enhanced efficiency.
4 cl, 4 dwg, 1 tbl