Lining for aluminium electrolyser having inert anodes
SUBSTANCE: lining comprises a bottom and current-carrying elements made of aluminium, liquid in the upper part contacting melted aluminium and solid in the lower part, and installed so that they pass through the bottom vertically. The bottom is made from taller bottom blocks having projections and shorter bottom blocks, at that the shorter bottom blocks are mounted at the ends of the bottom. The shorter bottom blocks alternate with the taller bottom blocks having projections. Vertical channels are provided in the projections of the blocks over the entire thickness of the block for the mounting of current-carrying elements. The current-carrying elements are attached in the lower part to a current-carrying collector shaped as a plate which extends horizontally out of the ends of the bottom blocks and longitudinal sides of the cathode casing. The current-carrying elements are L- or T-shaped. The bottom blocks are made of high-aluminous concrete annealed up to 1200°C or comprised of several layers: a working layer, made of high-aluminous concrete with the thickness equal to 0.4-0.6 of the bottom block thickness, and the secondary layer, made of fireclay castable concrete - the remaining part. Interconnection of the bottom blocks is made of high-aluminous concrete with reduced viscosity or by means of a gluing or cementing composite with the joint thickness of 5-20 mm.
EFFECT: decreased labour intensity at mounting, reduced power consumption and improved operational reliability of the electrolyser.
4 cl, 9 dwg
The invention relates to ferrous metallurgy, in particular to the electrolytic production of aluminum, the aluminum lining of the cell.
Well-known lining for aluminum cell performed by the blocks of refractory concrete. The concrete mixture is prepared in the following proportion: 15% quick setting cement, 85% filler-anthracite, 10% lime, and 6% water. After forming the blocks of the classic methods vibratory compaction they arrive in the drying chamber for receiving the grasping and removal of the main part of water at a temperature of 450°C. Setting blocks in the electrolytic cell and the connection joints produced in the traditional way (SU inventor's certificate No. 1050574, SS 3/08, publ. 23.10.83).
The disadvantage of this lining of an aluminum reduction cell is that with this method of manufacturing units with an aggregate of anthracite during operation of the electrolytic cell will have the oxidation of the coal component of the refractory blocks air from the outside through the holes in the cathode casing and the inner side (from the melt), carbon monoxide (CO). As a result, there will be destruction of refractory blocks, which will further lead to the penetration of the melt of the electrolyte to the cathode casing and in the worst case developments will lead to the departure of metal and electron�that of the bath.
Also known lining for aluminum cell (mesh) made of pre-cast blocks on the basis of cryolite or cryolite in a mixture with aluminum oxide (alumina), and carbonaceous material. Units are manufactured as follows: a mold is filled with a certain amount of the crushed carbon material is added about 20% by weight. aluminium oxide and all pre-poured molten cryolite. Out of the blocks laid out bottom and side lining, on the abutting surface is covered with a layer of powdered or molten cryolite and then the whole lining is heated to weld the blocks to each other in General monolith (USSR Patent No. 252224, C22D 3/02, 3/12, publ. 10.09.69).
The disadvantage of this design of the lining of an aluminum reduction cell is that when using such blocks on the basis of cryolite with a melting temperature of 1010°C there is always the risk of melting the blocks resulting from disorders of the technological process and the growth temperature of the melt.
Closest to the claimed invention is the lining of an aluminum reduction cell, in which the bottom is made of a refractory, neurolingo material (concrete) and covered with a layer of titanium diboride, which does not interact with liquid aluminum. The current deflecting elements are made and� aluminum in the form of a truncated cone, liquid in the upper part in contact with the molten aluminum cathode and solid in the lower part in contact with the cathode bus, and set passing vertically through the bottom (Patent RF №2281986, SS 3/08, publ. 20.08.2006).
This design allows to exclude horizontal currents in the cathode, and consequently reduce circulation and wave border of the metal with the electrolyte, and this directly affects the performance of current efficiency and energy consumption; to reduce filtering the melt through the bottom and on the limits of the cathode collector element - lining, to reduce the introduction to homeland alkali metals and, to engage the extended lifetime of the cell.
However, the installation of a vertical collector elements in a monolithic bottom, put in 4-5 layers, it is not technological: first-requires complex formwork, second - pouring concrete with a volume of 50-60 t is a difficult and long process; thirdly, the drying and heating of such concrete lining will take from 10 to 20 days otherwise there can be explosive allocation of steam, leading to destruction of the lining.
Furthermore, the use of the collector elements in the form of an inverted truncated cone, the upper part of which is in a liquid state, and the bottom - in solid, lead to the fact that are not soluble in the electrolyte� alumina will settle on the bottom of the tank and clog the channels of the collector elements in the furnace hearth. This will lead to an increase of the voltage drop in the cathode, and in the worst case developments may even lead to a complete loss of contact between the liquid cathode and solid parts of the collector elements, which in turn can cause rupture of a series of electrolytic cells and thereby dramatically reduce the energy efficiency of the cell.
Besides, installing and running the collector elements in the form of an inverted cone with the ratio of the area of the upper section to the lower to 1:2 and in a quantity equal to or greater number of anodes in the prototype, has serious disadvantages in the form of substantial heat removal carried out by the collector elements of aluminum, to fill which will need to increase the interelectrode gap. Thereby increasing the power consumption required for the production of tons of electrolytic aluminum. The area of the lower section is determined acceptable for aluminum current density of 0.65 A/mm2. This means that for a conventional electrolytic cell for a current of 120 kA with 16 anodes, and 16 collector elements, the dimensions of the latter will be ⌀120mm in bottom, and a width of 170 mm in the upper parts, respectively.
The object of the invention is the development of energy efficient design of the lining, which reduce consumption of electricity for a aluminum and provide�assure trouble-free operation of electrolytic cells by excluding cases of clogging the channels from the collector elements in the furnace hearth.
The technical result is the reduction of heat removal carried out by the collector elements of aluminum and obtaining stable electrical resistance of the collector elements throughout the lifetime of the cell.
The solution of this problem is provided by the fact that in the lining of aluminum cell with inert anodes enclosed in the cathode casing comprising a bottom made of a refractory, neurolingo material, and collector elements of aluminum, made of liquid in the upper part in contact with the molten aluminum and solid at the bottom, and set passing vertically through the bottom, according to the inventive solution, the bottom is made of bottom blocks of greater height with protrusions and bottom blocks of lower height, with large blocks of lower height installed at the ends of the hearth, and bottom blocks are smaller in height interspersed with large blocks of greater height with the protrusions, and the protrusions of the blocks, the entire thickness of the block is made of vertical channels for the installation of the collector elements, in addition, the current deflecting elements in the lower part is attached to conductive collector, made in the form of a plate, shown out horizontally from the ends of bottom blocks and through the longitudinal side of the cathode shell.
The implementation of bottom blocks smaller and Bo�LSA height, and also the fact that hearth blocks greater height provided with projections and are provided with channels for the collector elements, and the entrance to the channel is higher relative to the level of the hearth, to minimize the possibility of clogging the channels and reduce energy losses.
The connection of the collector elements of the current to the collector, made in the form of a plate, shown out horizontally from the ends of bottom blocks in contrast to the vertical output down (the prototype), provides a significant reduction in heat loss, resulting in reduced power consumption when receiving tons of aluminum. The plates are arranged inside the housing, and most of the heat remains in the tub.
The invention complement private distinctive features that contribute to the achievement of the task.
According to clause 2, of the claims - in order to eliminate cases of clogging the channels from the collector elements at the bottom of the alumina, the current deflecting elements are G - or T-shaped, which allows the position of the channel to the side surface of the protrusion of the bottom of the block.
According to clause 3 of the claims - deck blocks are made of high-alumina refractory concrete, which is annealed to 1200°C, or of several layers: the working layer made of a high alumina concrete with a thickness of 0.4-0.6 ottolini block, and the secondary layer is made of silica-concrete - else.
At a temperature of 1200°C is in the process of sintering the components of concrete, formed of ceramic communications and concrete is gaining maximum strength. In the impregnation of the working components of the electrolyte layer, the latter reaching the secondary layer will react with the formation of albite, which, in turn, to immerse yourself in metal fluorides, will create a highly viscous glassy silicate system, preventing further penetration of the electrolyte components.
According to clause 4 of the invention is the filling of the interconnect joints between the individual units in the bottom is high-alumina refractory concrete with low viscosity or by gluing or cementing composition with a thickness of 5-20 mm.
The filling of the interconnect joints high-alumina refractory concrete with low viscosity ensures good filling of the seams on the top, even for complex profile of the lateral surface of the bottom block. The connection joints using adhesive or cementing composition reduces the area of the interconnect joints and provides the solidity of the hearth, and this in turn reduces the chance of leaking of the electrolyte in the lining.
The invention is illustrated graphic material.
On Fig shows the proposed lining of an aluminum reduction cell, shown with cut ¼ parts;
Fig.2 shows a bottom block Assembly, shown with a cutout;
Fig.3 shows the current deflecting elements in the collection current to the collector;
Fig.4 presents the lining of an aluminum reduction cell from the collector elements of the G-shaped;
Fig.5 - hearth block from the collector elements of the G-shaped;
Fig.6 shows the current deflecting elements of the G-shaped Assembly with conductive collector;
Fig.7 shows a hearth block from the collector elements of the T-shaped;
Fig.8 shows the current deflecting elements of the T-shaped Assembly with conductive collector;
Fig.9 shows a bottom block Assembly made according to claim 6. of the claims.
The lining of an aluminum reduction cell with inert anodes includes steel cathode casing 1, bottom blocks greater height of the protrusions 2, bottom blocks of lower height 3 installed in the bottom blocks of channels 4 2 collector elements 5 made of aluminum, with the fluid part 6, the conductive collector 7 made of aluminum plates with facing outward part 8, the interconnect joints 9 out of high alumina concrete, side blocks 10, refractory layers made, for example from fireclay, high alumina, magnesia, magnesia bricks and insulating materials 11 that m�may be made, for example, of grog-lightweight, vermiculite, pentatomidae, diatomite, calcium silicate, secondary layer bottom block 12 made of silica concrete.
In order to fully eliminate cases of clogging the channels from the collector elements at the bottom of the alumina, the collector elements 5 are made G - or T-shaped, i.e. the upper part of the collector element 6 is turned about 90° with the output of the channel on the side surface of the protrusion of the block 2 in the case of G-shaped. Or in the case of the T-shaped block, the upper part of the collector element 6 forks and also opens onto the lateral surface of the ledge hearth block 2.
To better fill interconnect joints between deck units are encouraged to use high-alumina refractory concrete with a low viscosity, i.e. use samarasekera concrete. After mixing with a small amount of water to form concrete, which spreads and degassed without the application of vibration. He has all the advantages of low concrete (low porosity, high density, strength, abrasion resistance, heat resistance), it forms a smooth mirror surface. The use of such concrete suitable for the lining of the way places, such as interconnect seams.
For the purpose of formation of a monolithic scat�s from bottom blocks it is possible to use their bonding. This connection method reduces the area of the interconnect joints and provides the solidity of the hearth, and this in turn reduces the chance of leaking of the electrolyte in the lining. You can use adhesive or cementing composition, the thickness of the seam will be 5-20 mm.
Typically, blocks of high-alumina refractory concrete is calcined to a temperature of 900°C, in this case it is proposed to burn them to 1200°C. At this temperature, the process of sintering the components of concrete, formed of ceramic communications and concrete is gaining maximum strength. In this case, hearth units have a high resistance to cryolite-alumina melt.
If the hearth blocks made of several layers: the working layer of high-alumina concrete with a thickness of 0.4-0.6 times the thickness of the block, and a secondary layer made of aluminosilicate concrete, in the impregnation of the working layer components of the electrolyte last, when he reached secondary layer will react with the formation of albite, which, in turn, to immerse yourself in metal fluorides, will create a highly viscous glassy silicate system, preventing further penetration of the electrolyte components.
Installation of the lining of an aluminum reduction cell with inert anodes is as follows.
Hearths�, from high-alumina refractory concrete performed in separate blocks, which, after molding process pass through the stages of drying and firing, is mounted for 5-8 hours, the quality of the blocks will be obviously higher than that of monolithic hearth poured in place.
Initially assemble bottom blocks, this molded hearth block, provided with channels, pre-placed United conductive collector from the collector elements (vertical bars), there are fixed, then hearth block is carried to the place of installation of the lining.
After Assembly and installation of steel cathode casing 1, its bottom poteryatsa refractory and insulating materials 11, and then, the surface of the refractory layer is covered with a layer of granular material which acts as a levelling of the pillow upon which the hearth blocks with a certain pitch, between adjacent blocks of clearance 30-50 mm, inter-seam 9. After this is done, the side walls of the lining of the so-called "edge" placed around the perimeter of the cathode casing between the bottom blocks and the lower part of the walls of the cathode casing and consisting of a layer of insulating material mounted adjacent to the walls of the casing, and a refractory material, can be mounted next � insulating material. The exposed portion of the conductive collectors screwed, lateral lining, ensuring the tightness of the eyebrows, at the same time not preventing thermal expansion of aluminum manifolds. "Edge" is the basis for the installation side of the lining. Installation of side blocks of a non-metallic refractory compounds produced in one row along the walls of the casing 1 includes attaching them to the walls of the casing and greasing all of the support and the mating surfaces. As gluing or cementing composition can be used, for example, torremans, mortars or refractory concrete containing powder of silicon carbide.
The final and responsible operation of mounting the lining is filling interblock bottom seams between blocks.
The proposed lining of an aluminum reduction cell with inert anodes will allow the installation by reducing the labor intensity, improve technical and economic performance by reducing energy consumption and improve the reliability of operation of the cell due to the exclusion of cases of clogging the channels from the collector elements in the furnace hearth.
1. The lining of an aluminum reduction cell with inert anodes placed in the cathode casing comprising a bottom made of a refractory neurolingo material, and the collector element� aluminum made of liquid in the upper part in contact with the aluminum melt and the solid at the bottom and set passing vertically through the bottom, wherein the bottom bottom blocks made of greater height with protrusions and bottom blocks of lower height, with large blocks of lower height installed at the ends of the hearth, and the hearth blocks smaller in height interspersed with large blocks of greater height with the protrusions, and the protrusions of the blocks in all its thickness is made vertical channels for the installation of the collector elements, while the collector of the elements in the lower part is attached to conductive collector, made in the form of a plate, derived horizontally from the ends of bottom blocks of the bottom and through the longitudinal side of the cathode shell.
2. The lining according to claim 1, characterized in that the collector elements are G - or T-shaped.
3. The lining according to claim 1, characterized in that the bottom blocks are made of high alumina concrete, fired to 1200°C, or of multiple layers consisting of the working layer made of a high alumina concrete with a thickness of 0.4-0.6 times the thickness of the block, and a secondary layer made of aluminosilicate concrete with a thickness corresponding to the thickness of the rest of the block.
4. The lining according to claim 1, characterized in that the interconnect connection�o blocks are made of high alumina concrete with low viscosity or by gluing or cementing composition with a thickness of 5-20 mm.
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
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
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