Electrolysis unit for aluminium making
SUBSTANCE: electrolysis unit consists of the following: cathode device with a pool with carbon bottom, the pool is formed by carbon blocks enclosed in metallic casing with flame proof and heat-insulating materials arranged between metallic casing and carbon blocks; anode device including carbon anodes connected to anode bus, the anodes are arranged in upper part of bath and absorbed in fused electrolyte; on the carbon hearth along the anode perimeter the pedestals, or the floats resistant to destruction in cryolite aluminous fusions and liquid aluminium are located. The top surface of a pedestal or a float acts higher than a level of cathodic aluminium and a pedestal or floats can be moved and/or replaced if necessary. Pedestals or floats are made of carbon, carbide of silicon, their combination. The top surface of the pedestal or the float is flat, convex, concave, or inclined to the horizon.
EFFECT: decrease of specific power consumption due to reduction of interpolar gap, ohmic resistance and voltage drop in interpolar gap, increase of current output due to increase of hydrodynamic resistance to movement of fusion near the aluminium-electrolyte interface along the anode perimeter and decrease of mixing of fusion and counter reactions of metal with anode gases.
6 cl, 6 dwg
The invention relates to ferrous metallurgy, in particular to the electrolytic production of aluminum, namely to the design of electrolytic cells for aluminium production.
Known electrolytic cell [H. Chang, V. de Nora and George.And. Sekhar "Materials used in the production of aluminum by the Era-Hall". - Publishing house of Kazan state University, Krasnoyarsk. - 1998] containing cathode device and the anode device. Cathode apparatus comprises a bath with a coal furnace hearth, lined with carbon blocks with built-in current conductors enclosed in a metal casing. Between the metal casing and the coal blocks placed refractory and insulation materials. The device comprises an anode carbon anode connected to the anode bus. The anodes are placed in the upper part of the bath and immersed in the molten electrolyte.
A disadvantage of the known design of the cell is what is designed for it technologies are characterized by very high specific energy consumption W defined by the equation
Usually in the technology of producing aluminum W=13-15 kWh/kg of metal. However, this power consumption is about 2 times b�lshe, than theoretically predicted. This is for two reasons:
1. The voltage V occupies most of the ohmic voltage drop in the electrolyte is determined by the value of Transconductance (mipolyseg.o) clearance (EMF). Typically this distance is about 5 cm.
2. The current efficiency η decreases with a sharp increase in the interaction (the so-called "reverse interaction") of the anode products (carbon dioxide) and cathodic products (dissolved aluminum) with increasing hydrodynamic mixing (circulation) of the electrolyte and/or metal.
Thus, one of the major drawbacks of the above design are the relatively high ohmic resistance of the EMF and high energy consumption.
Known electrolytic cell for aluminium production [US 4405433, C25C 3/08, publ. 20.09.1983], consisting of anode current supply, carbon anode, carbon cathode disposed under the anode with additional elements - "mushrooms", is made of titanium diboride, isolation, electrolyte, liquid aluminum, blumsom.
A disadvantage of the known design of the cell is insufficient thermo-mechanical and chemical resistance "mushrooms", is made of titanium diboride, especially on the borders of the metal-electrolyte; the complexity of attachment "mushrooms" to the bottom and the impossibility of implementing such an attachment nine existing electrolyzers, the small area of contact "mushroom" with the coal furnace hearth, as well as relatively high cost and the inability to efficiently remove the "mushroom" from the interelectrode gap, if necessary, for example, lowering the anode to the cathode.
The closest technical solution, selected as a prototype, is the electrolytic cell for aluminium production [RU # 111540, C25C 3/06, publ. 20.12.2011], including cathode device comprising bath with coal furnace hearth, lined with carbon blocks with built-cathode conductors enclosed in a metal casing, is placed between the metal casing and the coal blocks of refractory and insulating materials, anodic device containing carbon anodes connected to an anode bus bar, located in the upper part of the bath and immersed in the molten electrolyte, characterized in that on the bottom of the coal under each of the anodes are tables with higher specific electrical conductivity than the electrolyte, and resistant to degradation in cryolithology melts and liquid aluminum, moreover, the upper surface of the pedestal protrudes above the level of the cathode aluminum and pedestals are made with the ability to move and/or replacement if necessary.
The disadvantages of the known structures of the cell are: a relatively large amount of space in MPZ, develo�strap-tables, the weight and cost of the tables, the complexity of the displacement and/or replacement of the tables if necessary. If necessary the use of weights located inside the pedestal, for example cast iron "kettlebell" or fill, this may reduce the reliability of the design due to the difference in coefficients of thermal expansion of the material and the penetration of the electrolyte through the pores of the cabinets to the material of weighting, leading to premature corrosion and contamination of the cathode metal. Almost difficult the possibility of automatic control of vertical movement of the pedestal when changing the layer thickness of the cathode metal.
In addition to the above, the known disadvantage of the currently existing cell with horizontal electrodes (Fig.3, the anode 1 and cathode 2) is the fact that formed on the anode 1 gases rush to the edges of the anode, resulting in the movement of the melt 4. Around the perimeter of the anode 1 anode gases 7 upward, forming the hydrodynamic pressure at the interface of aluminum-electrolyte, formed a rising wave of aluminium 9. On top of the waves of the aluminum particles can break off and being trapped gas bubbles 7, rush upwards in the electrolyte 4 and to the anode 1, wherein the oxidized, i.e., the reverse reaction occurs, which reduces the current efficiency of the cell. In the result� this phenomenon the current output may be reduced approximately by 0.3%.
The technical result of the invention is to reduce specific power consumption by reducing inventories, the ohmic resistance and the voltage drop in inventories, the increase of current efficiency due to the increased hydrodynamic resistance to movement of the melt at the border of the aluminium-electrolyte interface along the perimeter of the anode, and therefore reduce mixing of the melt and "reverse" reactions of metal with an anode gases.
The technical result is achieved in that in an electrolytic cell for producing aluminum, comprising a cathode device comprising bath with coal furnace hearth, lined with carbon blocks with built-cathode conductors enclosed in a metal casing, is placed between the metal casing and the coal blocks of refractory and insulating materials, anodic device containing carbon anodes connected to an anode bus bar, located in the upper part of the bath and immersed in the molten electrolyte, what is new is that it is equipped with tables or floats placed along the perimeter of the anode in the interpolar gap at the boundary surfaces of the aluminum cathode-electrolyte, the upper surface of which is above the level of the cathode of aluminum, with the possibility of moving and/or replacing cabinets or float if necessary. New also is the fact that cabinets and�and floats made of carbon blocks, in particular from waste in the form of a battle standard bottom blocks, baked anodes and/or electrodes, silicon carbide, or a combination of carbon and silicon carbide-based and/or floating on the border of the cathode metal/electrolyte interface due to the difference of densities of the materials. The outer surface of the blocks or float pre-coated or impregnated protective inhibitory substances; under each anode can be set from 1 to 240 tables or floats (floats) can be any shape, such as a parallelepiped, prism, cube, hexagonal, orthogonal, spherical, ellipsoidal, hemispherical, cylindrical, and combinations of forms, etc. the Upper surface of the pedestal or float is made flat, or convex, or concave, or inclined to the horizon.
The invention complement private distinctive signs which also aim at solving the problem:
1. The floats have a density less than that of the cathode metal, but more than that of the electrolyte, floating on the border of the cathode metal/electrolyte interface due to the difference of densities of materials, and the upper surface of the float protrudes above the level of the cathode aluminum.
2. Tables or floats can be made of carbon blocks, blocks made of silicon carbide or combinations thereof, in particular from waste in the form of a battle standard blocks, �beginnig anodes and/or electrodes, located on the border of the cathode metal/electrolyte interface due to the difference of densities of the materials.
3. Tables or floats, before to be placed in the space MPZ, covered in vacuum packaging foil of the cathode metal and is heated to a temperature as close as possible to the temperature of electrolysis, but lower than the melting point of the metal cathode. Then the Cabinet or the float is placed in the space of the stocks.
4. Cabinets can be made of silicon carbide and/or material type ANAPLAST.
5. The outer surface of the blocks or float pre-treated/impregnated protective inhibitory substances.
6. Around the perimeter of the anode can be set from 1 to 240 tables or floats.
7. The upper surface of the tables or floats are flat, or convex, or concave, or inclined to the horizon.
8. The floats may be of any shape, such as a parallelepiped, prism, cube, hexagonal, orthogonal, spherical, ellipsoidal, hemispherical, cylindrical, combinations of various forms, etc., but design features and unification of the floats can be considered for the optimum design and the process of electrolysis.
These differences allow to draw a conclusion about conformity of the proposed technical solution the criterion of "novelty". The features distinguishing the claimed method from the prototype, not identified in the d�ugih technical solutions in the study of this and related areas of technology and, therefore, provide the claimed solution to the criterion of "inventive step".
The invention is illustrated by drawings 1-6.
The electrolytic cell contains a carbon anode with an anode current supply 1, coal bottom (cathode) 2. The bottom surface coal anode immersed in the electrolyte 3. Inside of the cell is lined, the lining 6. The electrolytic cell is equipped with a traditional device for supplying raw materials (alumina, forsale, etc.) and the flue 8, the device for current supply 3 to the cathode 2. In the interpolar gap (EMF) on the boundary surfaces of the cathode metal-electrolyte 4 on the perimeter of the anode 1, in the place where usually the wave is formed of the metal cathode 9 (Fig.3), placed tables or floats in a box 10 (Fig.4) or other forms or their combinations (Fig.5), including prism, cube, hexagonal, orthogonal, spherical, ellipsoidal, hemispherical, cylindrical, and at the bottom of the cabinets or the float has a through hole 12 for the flow of aluminum (Fig.5). Unlike cabinets float attach brackets 11 on the perimeter of the anode 1 (Fig.6), the bracket 1 is made of silicon carbide or similar non-conductive material stable in cryolithology melts and aluminum at temperatures of 950-1100°C.
The installation of aluminium electrolytic cell is carried out following�m.
Tables or floats, before to be placed in the space mPas, can be wrapped in vacuum-sealed foil cathode metal with the aim of closing the surface pores, protect the float from oxidation in air, improving heat transfer and heated to a temperature as close as possible to the temperature of electrolysis, but lower than the melting point of the metal cathode. Then the float is placed in the space of the stocks.
Thus there is improvement following TEP aluminum electrolysis: a decrease in inventories, operating voltage and the specific power consumption, increasing the current efficiency and the performance of the cell.
1. The electrolytic cell for producing aluminum-containing cathode device having a tub with a carbon bottom, lined with carbon blocks with built-cathode conductors enclosed in a metal casing, is placed between the metal casing and the coal blocks of refractory and insulating materials, anodic device containing carbon anodes connected to an anode bus bar, located in the upper part of the bath and immersed in the molten electrolyte, characterized in that it is provided with blocks in the form of tables or floats placed along the perimeter of the anode in the interpolar gap at the boundary surfaces of the aluminum cathode-electrolyte, the upper surface of which you�Tupa above the level of the cathode of aluminum, is arranged to move and/or replace them if necessary.
2. The electrolyzer according to claim 1, characterized in that the blocks in the form of tables or floats made of carbon materials, in particular from waste in the form of a battle standard bottom blocks, baked anodes and/or electrodes, silicon carbide, or a combination of carbon and silicon carbide-based and/or floating on the border of the cathode metal-electrolyte interface due to the difference of densities of the materials.
3. The electrolyzer according to claim 1, characterized in that the outer surface of the blocks or float pre-coated or impregnated protective inhibitory substances.
4. The electrolyzer according to claim 1, characterized in that each anode set from 1 to 240 tables or floats.
5. The electrolyzer according to claim 1, characterized in that the floats are made of any shape, for example in the form of a parallelepiped, prism, cube, hexagonal, orthogonal, spherical, ellipsoidal, hemispherical, cylindrical, and combinations of the mentioned forms.
6. The electrolyzer according to claim 1, characterized in that the upper surface of the pedestal or float is made flat, or convex, or concave, or inclined to the horizontal.
SUBSTANCE: invention relates to a carbon article which is produced by burning a mixture at least containing coke. The coke has low graphitisability. Also disclosed is a method of producing a carbon article, which includes mixing anthracite, graphite and/or low-graphitisability coke or mixtures thereof with at least one binding material selected from a group of oil- or carbon-based binding materials, as well as binding materials based on synthetic polymers and any mixtures of said binding materials and optional additives, endowing the mixture with a given shape, firing the moulded mixture and optional graphitisation of the fired moulded article. The invention discloses use of the carbon article as a cathode block of an aluminium electrolysis cell and a blast-furnace brick.
EFFECT: longer service life of the article, particularly a cathode block.
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
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
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