Lining method for cathode assembly of electrolyzer for primary aluminium production (versions)
SUBSTANCE: method includes filling the cathode assembly casing with heat insulation layer, building up a refractory layer, followed by packing layers, installing hearth and side blocks, followed by sealing the joints between them with cold ramming paste. In accordance with the first alternative of the presented method an elastic element made of compact fibreboard with the thickness of (2.5-4)⋅10-4 of the cathode width is installed between the heat insulation and refractory layers. According to the second alternative of the presented method flexible graphite foil is installed between the heat insulation and refractory layers and an elastic element of the abovementioned fibreboard is mounted beneath it.
EFFECT: reduced power consumption during the electrolyzer operation by improving the stabilization of the thermal properties of the heat insulation in the basement, extended life of electrolyzers.
6 cl, 5 dwg, 1 tbl
SUBSTANCE: invention relates to the method of obtaining of an electrolyser cathode pack for aluminium production. The method includes preparation of initial materials containing coke and powder of solid material such as, for example TiB2, and also, if necessary, carboniferous material, mixing of initial materials, formation of the cathode pack, carbonisation, graphitisation and cooling, note that graphitisation is performed at temperatures from 2300 up to 3000°C, in particular from 2400 to 2900°, and the second layer made with the thickness amounting from 10 up to 50%, in particular from 15 up to 45% of the total thickness of the cathode pack.
EFFECT: high wear resistance with reference to aluminium and cryolith, and decrease in energy consumption are provided.
SUBSTANCE: method includes charging of the powdered material in the cathode casing of the electrolyser, its levelling using rack, coverage of the charged material by dust isolating film and compaction performed by two stages: preliminary static and final dynamic action by means of the successive movement of the work organs of the static and dynamic compaction along the longitudinal axis of the cathode of the aluminium electrolyser via the resilient gasket made out of at least two layers: bottom preventing extrusion of the powdered material in front along the movement , and top ensuring gasket engagement with the work organ of the static compaction, at that the dynamic action is performed by vibration unit connected with the static treatment unit by means of the resilient elements with possibility of simultaneous movement relatively to the horizontal and vertical axes.
EFFECT: reduced expenses for lining materials and reduced labour costs during their installation.
7 cl, 9 dwg
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
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
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