Method for manufacturing combined bottom blocks. RU patent 2510822.
 Cathode section of aluminium electrolyser / 2510818Invention 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. |
 Electrolytic cell for production of aluminium / 2509830On 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. |
 Electrolysis unit for aluminium manufacture / 2499085Electrolysis 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. |
 Composites for wet cathodes and their use in aluminium production / 2487956Composite 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. |
 Cathode of electrolytic cell for production of aluminium and method of its repair / 2483142Proposed 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. |
 Cathode device for aluminium electrolytic cell with embossed hearth / 2482224Cathode device of an aluminium electrolytic cell with an embossed hearth contains a lined cathode shell ad a hearth composed of higher bottom blocks with projections and lower bottom blocks. The lower bottom blocks are installed at the cathode device hearth butt ends. The lower bottom blocks alternate with higher bottom blocks with projections or are installed in the projection centre of the electrolytic cell anode array, with at least two higher bottom blocks with projections, alternating with lower bottom blocks, installed at the both ends of the electrolytic cell anode array. The bottom block projection height is equal to 0.1÷0.6 of that of the smaller bottom block. The top parts of higher bottom blocks have level edges. The bottom blocks projections are made of a refractory non-carbon material, resistant to hot melt effect. |
 Method of producing metal by molten-salt electrolysis / 2471892Method for electrolytic production of metal in an electrolysis cell, having a cathode, an anode and collectors of impurities dissolved in the electrolyte, involves passing cathodic current through the cathode to obtain metal at the cathode and deposit impurities on the collector. The collector, which is placed between the anode the cathode, is a bipolar porous collector electrode which is a cellular matrix which is inert to the metal deposited at the cathode and the electrolyte. The bipolar porous collector electrode is in form of an open porous structure having internal pores or capillaries, or channels, or cavities, which are particularly V-shaped and/or W-shaped and/or S-shaped and are filled with the metal which is deposited at the cathode. The method employs a bipolar porous collector electrode, wherein the internal pores or capillaries, or channels or cavities are wettable by metal, and have dimensions, particularly diameter and length, which are sufficient for them to hold the metal and prevent spontaneous flow of metal from them due to surface tension forces of the metal. |
 Cathode device of aluminium electrolyser / 2458185Cathode device of aluminium electrolyser includes housing, bottom blocks with cathode rods, refractory casing under bottom blocks, side refractory, insert blocks from carbide-silicon material mounted close to side refractory. From above the side refractory is equipped with flange sheet mounted horizontally, between the upper surface of insert carbide-silicon block and flange sheet there is combined fire-resisting insert that is equipped with filling material and fire-resisting dielectric elements, the height of the insert is equal to 0.10-0.20 of insert block height. |
 Doped sintered article based on zircon and zirconium dioxide / 2456254Invention relates to sintered articles made from zircon and zirconium dioxide for use in a glass-melting furnace, particularly in articles used as supporting blocks for electrodes, or in an electrolysis cell in contact with molten cryolite. The initial load for producing the articles contains 5-50% zircon and has the average chemical composition given below, in wt % based on oxides with sum total of 100%: silicon dioxide SiO2 and zirconium dioxide, where content of zirconium dioxide ZrO2 is at least 75%, 0.2-6% dopant selected from Nb2O5, Ta2O5 and mixtures thereof, possibly a stabiliser selected from Y2O3, MgO, CaO, CeO2 and mixtures thereof in amount of 6% or less, 'other oxides' in amount of 6.7% or less. Components are formed from the initial charge and then sintered to obtain articles. |
 Electrolysis unit for aluminium manufacture / 2454490Electrolysis unit consists of the following: cathode device including pit with carbon bottom, the pit 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; and point feeding system (PFS) including punch pin for electrolytic crust and alumina feeder. On carbon bottom under each PFS feeder there are units installed resistant to destruction in cryolite-alumina melt and molten aluminium. Upper base of unit is located at level and above level of molten aluminium not exceeding 2 cm. Units may be made from carbon or from silicon carbide, or from mixture of titanium diboride and aluminium oxide on high-temperature connection. Inserts from heavy material, such as cast iron, may be mounted inside units. Relation of squares of upper and lower bases of units changes from 1:1 to 1:2. Square value of upper basis of unit is chosen considering quantity of alumina loaded by dosemeter - from 30 to 80% - falling on it. Units may be covered by titanium diboride. Upper basis of units may be flat or convex, or inbent. |
 Graphitic cathode for electrolysis of aluminum / 2245395The 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. |
 Impregnated graphitic cathode for electrolysis of aluminum / 2245396The 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. |
 Cathodic device of aluminum electrolyzer / 2245397The 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. |
 Aluminum cell / 2256009Cathode 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. |
 Method of forming protective coating for carbon containing components of electrolysis cell / 2257425Method 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. |
 Side lining of aluminum electrolyzer / 2263162Proposed 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. |
 Cathode facing to aluminum cell / 2266983Cathode 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. |
 Method of mounting side lining of cathode device for aluminum electrolyzer / 2270887Proposed 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. |
 Method of forming hearth for aluminum electrolyzer / 2270888Proposed 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. |
 Method of mounting cathode section of aluminum electrolyzer / 2270889Current-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. |
FIELD: metallurgy.
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
The present invention relates to electrolytic aluminum production, namely, cathode blocks, used in the electrolytic cells for obtaining primary aluminium.
In electrolyzers for obtaining primary aluminium in the construction of cathode devices use carbon units, representing a burnt homogeneous mixture of termoanthracite and/or graphite, as well as pitch. Carbon blocks are called hearth or cathode blocks, which together with a side lining form the mine electrolysis baths. The mine is located molten electrolyte, which is at the top dive anode blocks, consisting of calcined homogeneous mixture of coke and pitch. In the electrolysis cell, flow through electrolytic decomposition reaction of alumina, is the precipitation of aluminum on the bottom blocks. During operation of the cell is often premature display it fails due to the destruction of the bottom and the penetration of aluminum melt and the electrolyte in the base of the bath.
The main negative factor that reduces the period of the electrolyzer in working condition, is the penetration of sodium in the structure of cathode blocks, resulting in a "swell" coal-fired units, which is reflected in the value of sodium expansion. In the process of penetration of sodium, cathode blocks change their structure, resulting in the formation of cracks and cavities.
Another factor that negatively affect the service life of electrolytic cells is constant movement components molten electrolyte and aluminum on the surface of the bottom. This phenomenon is caused by magneto-hydrodynamic (MHD) effects. Due to the constant movement components in furnace hearth carbon bath is its wear, and this deterioration can have a local character. In other words, for a given plot bottom erosion coal blocks can be critical in nature, as in the rest of bottom wear will be minimal.
By the decision of problems of increase of service life of the cell is directly improving the quality of cathode blocks and the use of fundamentally new carbon blocks, having in its composition composite layer, so - called combined bottom blocks (PBC). These units must ensure the formation of near-cathode layer of molten aluminium due to the content in them "wetting" supplements of bored metal, in particular of titanium diboride. Despite its high cost, the use of titanium diboride in the form of "wetting" additions due to its inertia to aggressive environments arising in the electrolysis cells, i.e. resistance to erosion, as well as the ability to soak liquid aluminum.
The result of the formation of near-cathode layer of aluminum furnace hearth carbon will be reduced penetration of sodium in the cathode block in the base of the bath. In addition, the aluminium layer on the working surface of the combined bottom blocks will allow to avoid the formation of a layer of electrolyte between molten aluminum and furnace hearth baths, which, in turn, affects the voltage reduction, in consequence of which would see a reduction of energy consumption for the production of aluminum.
However, when creating such a combined bottom blocks the problem arises whether there is a difference in the physical-mechanical characteristics between the carbon layers of the substrate and surface (desktop) layer. The surface layer obviously contains some amount of titanium diboride and has a coefficient of thermal linear expansion (CDLR) and sodium expansion different from carbon substrate (bottom of the unit).
Taken earlier attempts to create "wetted" cathode blocks were not very successful. These blocks were made either completely out of titanium diboride that it is not economically feasible, either by drawing on a regular carbon blocks suspensions, pastes, or items from titanium diboride (patent US no 5527442, SS 3/08, publ. 18.06.96), but the difference in CTLR and sodium expansion of these materials leads to the formation of cracks and cavities filled during operation electrolyte, and subsequent peeling composite layer.
Another option of creating a composite deck blocks was the creation of a carbon substrate one of the surface layer with the content of titanium diboride or more of the surface layers with different content of titanium diboride (application for invention RU №2010148769, publ. 20.06. 2012). However, during firing data blocks, there are significant thermal stress due to different CTLR substrate and the surface layers, which leads to their subsequent destruction. In addition, baked goods, when used in electrolysis bath will also adversely affect its operation life. As a result, various thermal and sodium expansion of data layers combo units is quick exfoliation wetted layer from coal bottom of the tub.
Closest to the claimed method is a method of manufacturing multilayer cathode structure (patent RU №2227178, SS 3/08, publ. 20.06.1996), including the introduction of material carbon substrate cathode in the form and the application of a layer of heat-resistant composite the material. However before applying the composite layer produce wavy surface carbon substrate that, according to the authors, when vibroforming procurement facilitates the mixing layer and thus to compensate for the difference in thermal extensions. According to the patent, the contents of titanium diboride in composite layers (depending on the number of layers should be varied from 10.0 to 20.0 to 50.0 to 90.0%. Apparently, getting a layer for casting of billets, with the average between carbon substrate and composite layers of physical-mechanical properties impossible. Perhaps the authors of the patent require the movement of material from carbon substrate in the direction of the compensation layer and Vice versa, and receiving, thus, layers with homogeneous mixture. However, this move may be limited settings vibroshaping providing procurement of multilayer with a given block apparent density. In other words, a blend layers with the help of vibration must be set such amplitude and frequency, which will allow the material to move to an adequate distance and to maintain a sufficient density of produced billets. Moreover, the formation of the "green" ingots using weights, which creates the static-dynamic load on the material and does not allow him to move freely along the height of the matrix.
The basis of the invention is aimed at developing ways of making combined bottom blocks that can be wetted with liquid aluminium and resist wear and peeling of the wet coating.
The technical result is the production of composite deck blocks with obviously the same physical and mechanical properties, providing no cracks, delaminations and void on the boundary layers.
The achievement of the above technical result is the fact that the method of production combined bottom blocks for aluminium electrolyzers, including the introduction of material carbon substrate in the form and the application of a layer of heat-resistant composite material containing bored metal seal the contents of the form in the form of cathode blocks and the firing of the cathode unit, used as material carbon substrate and the layer of heat-resistant composite material, materials with close coefficients of thermal linear expansion and values sodium extensions and the following granulometric composition: the content of fractions in carbon substrate (-10+0,071) mm - 76±10 wt.% and (-0,071+0) mm - 24±10%by weight, the content of the factions in the layer of heat-resistant composite material (-10+0,071) mm - 50±30% by weight and (-0,071+0) mm - 30+50 wt.% this material carbon substrate injected into the pre-heated up to the temperature of the material form.
How complement private signs, facilitating the achievement of a technical result, namely:
The layer of heat-resistant composite material when compressed is not more than 8,0% of the height of the cathode unit, and the content of diboride metal 20,0-80,0% the seal of the cathode unit carried vibroforming, and firing is at 1100 OC for 5 hours.
The proposed method of making combined bottom blocks you can get a ready-made carbon products, the structure of which does not contain cracks, due to the adhesion between the layer of carbon substrate and the layer of heat-resistant composite material. This phenomenon, in turn, leads to the long service life of products in electrolyzers for obtaining primary aluminium.
As carbon substrate layer heat-resistant composite material is a mixture of bottom block, consisting of termoanthracite and/or graphite, and peck. While both layers are on their basic physicomechanical properties similar to each other, due to grain size composition of heat-resisting material, chosen to blend carbon substrates. The table presents the composition of the charge of the combined bottom of the unit.
Table LayerFraction, mm
(-10+5) (-5+0)(-0,071)
(-0,071)
Carbon component
TiB 2Content, wt.%
Heat resistant composite material
10±5 40 ħ10 - 50 ą30Carbon substrate
28±5 48 ħ10 24 ħ10 -The mixture composition-resistant layer is selected so, that formed during burning of "green" procurement on the border of two layers does not occur thermal stresses, i.e. the values of the relative shrinkage and expansion of the substrate and heat-resistant composite layer are the same. On the boundary layers of the combined bottom of the unit does not occur flaking, scaling, and voids. In the annealed condition layer carbon substrate and composite heat-resistant layer have close to each other by the values of the coefficient of thermal linear expansion, and values sodium extension, which causes the continued work of the PBC in conditions of electrolysis.
To get pieces of the PBC (green blocks) ready homogeneous mass of bottom blocks with temperature 140-160±20 C is placed in a pre-heated to a temperature of 120±20 C steel matrix representing a box with a solid bottom and complete walls, and level to obtain a smooth surface of a substrate. Then is applied to the substrate composite heat-resistant layer with a temperature of 140-160 of + 20 C, which is aligned to obtain a flat surface. It fits the weights, creating specific pressure of 0,3 kg/cm 2 . The vibroshaping is within 7 minutes, after which the finished workpiece being fired at 1100 OC for 5 hours. Height thus obtained composite heat-resisting layer of the PBC is from 3,0% to 8.0% of the height of the workpiece. The lower limit is defined conditions electrolysis lifetime bottom of the unit, the upper limit of heat-resistant coatings limited from the economic point of view, in connection with the high cost of the coating material (TiB 2 ).
The results of tests on samples of the PBC shown in figures 1, 2 and 3, which shows the physical-mechanical and chemical properties of a combined bottom of the unit and heat-resistant composite layer.
Figure 1 shows the graphs of changes of thermal expansion of the surface layer of heat-resistant composite material (SP) and carbon substrate bottom of the unit (PB) during firing. The presented data were obtained in the determination of thermal expansion on separate samples of JV and the IB. As you can see, the nature of the graphs are the same, indicating homogeneity of composition of JV and PB, and that their granulometric compositions are stated in the claims.
Figure 2 presents the charts of thermal expansion annealed samples (SP) and carbon substrate (PB) with increasing temperature. As you can see, the form of the curves during heating is virtually the same.
Figure 3 shows the graphs of changes of penetration of sodium (sodium extension) in the samples of surface layer (SP) and carbon substrate (PB) for 120 minutes The nature of the graphs indicate uniform volume changes in layers surface layer of heat-resistant composite material and the substrate in the penetration of sodium.
1. Method of production of combined bottom blocks for aluminium electrolyzers, including the introduction of carbon material the substrate in the form and the application of a layer of heat-resistant composite material containing bored metal seal the contents of the form in the form of cathode blocks and the firing of the cathode unit, wherein the material carbon substrate and the layer of heat-resistant composite material use materials with close coefficients of thermal linear expansion and values sodium extension with the following granulometric composition: the content of fractions in carbon substrate (-10+0,071) mm - 76±10 wt.% and (-0,071+0) mm - 24±10%by weight, the content of the factions in the layer heat resistant composite material (-10+0,071) mm - 50±30% by weight and (-0,071+0) mm - 30±50 wt.% this material carbon substrate is administered in the form of pre-heated to the temperature of the material.
2. The method according to claim 1, wherein the compacted layer of heat-resistant composite material is not more than 8,0% of the height of the cathode unit and contains 20,0-80,0% by weight the diboride metal.
3. The method according to claim 1, characterized in that the seal of the cathode unit carried vibroforming and burning - in of 1100 OC for 5 hours.