Compiled and edited by Joseph C. Benedyk.
U.S. Patents
US9822457 — METHOD AND APPARATUS FOR LINING THE CATHODE OF THE ELECTROLYTIC CELL — United Company RUSAL Engineering and Technology Centre LLC (Russia) — The invention relates to method and apparatus for lining the cathode of the electrolytic cell for primary aluminum production. The method comprises filling the cell’s shell with powder material, leveling it with a rack, covering the fill material with a dust-proof film, and compaction. Compaction is performed in two stages: preliminary static and final dynamic treatment by consequent movement of static and dynamic work tools of compaction along the longitudinal axis of the cathode of the electrolytic cell through a cushion, which is made of at least two layers: a lower layer, which prevents pushing powder material forward in the direction of travel, and an upper layer, which provides for a coupling between the cushion and the static work tool. Static treatment unit of the apparatus, designed in the form of a roller with a drive, is connected to a dynamic treatment unit with a vibratory exciter by means of elastic elements.
US9771660 — METHOD OF VENTILATING AN ALUMINUM PRODUCTION ELECTROLYTIC CELL — General Electric Technology GmbH (Switzerland) — An aluminum production electrolytic cell comprises a bath with bath contents, at least one cathode electrode in contact with said contents, at least one anode electrode in contact with said contents, and a hood, defining interior area, covering at least a portion of said bath. The electrolytic cell is equipped for vent gases to be drawn from said interior area. The electrolytic cell also comprises at least one heat exchanger for cooling at least a portion of the vent gases drawn from interior area, prior to circulation thereof to interior area.
US9751775 — PROCESS FOR MAKING HIGH PURITY ALUMINUM OXIDE — Polar Sapphire Ltd. (Canada) — A method comprising contacting high-purity acid, high-purity aluminum, and high-purity water to form a first solution in a heated non-contaminating vessel, wherein the aluminum is employed in at least a stoichiometric amount relative to the acid, heating the first solution in a non-contaminating container, to provide a mother liquor and solid aluminum salts, separating the solid aluminum salts from the mother liquor, heating the solid aluminum salts in a non-contaminating crucible, to provide alpha aluminum oxide, and, optionally, washing the alpha aluminum oxide with high-purity water after some or all of the heating of the solid aluminum salts to provide the alpha aluminum oxide.
US9631289 — DRY CELL START-UP OF AN ELECTROLYTIC CELL FOR ALUMINUM PRODUCTION — Rio Tinto Alcan International Limited (Canada) — A method for starting up an electrolytic cell (20) for aluminum production having a cathode block (26) with an upper surface (32), the method comprising: disposing contact resistance material (46) over the upper surface (32) of the cathode block (26); lowering a plurality of anodes (28) to abut the contact resistance material (46); filling the electrolytic cell (20) and covering the anodes (28) with solid electrolyte material (72) comprising crushed electrolytic bath material, cryolite, or mixtures thereof; delivering electrical current to the anodes (28) to at least partially melt the solid electrolyte material (72) and raising the anodes (28) when a predetermined depth of molten electrolyte material has been reached.
US9611557 — SEAL ASSEMBLIES FOR CATHODE COLLECTOR BARS — MID MOUNTAIN MATERIALS, INC. (USA) — The cathode collector bar end portion extending through a window in a sidewall of an electrolytic cell for refining aluminum is snugly received in a central opening of a seal assembly. Such seal assembly maintains a hermetic seal preventing ingress of air through the sidewall window while permitting longitudinal (horizontal) movement of the collector bar and also movement in a vertical plane (side to side, or up and down, or diagonally) which can be caused by changing heat conditions inside the cell.
US9598783 — ALUMINUM SMELTER COMPRISING ELECTRICAL CONDUCTORS MADE FROM A SUPERCONDUCTING MATERIAL — Rio Tinto Alcan International Limited (Canada) — An aluminum smelter comprising: (i) a series of electrolytic cells, designed for the production of aluminum, forming one or more rows, (ii) a supply station designed to supply the series of electrolytic cells with an electrolysis current, the said electricity supply station comprising two poles, (iii) a main electrical circuit through which the electrolysis current flows, having two extremities each connected to one of the poles of the supply station, (iv) at least one secondary electrical circuit comprising an electrical conductor made of superconducting material through which a current flows, running along the row or rows of electrolytic cells, characterized in that the electrical conductor made of superconducting material in the secondary electrical circuit runs along the row or rows of electrolytic cells at least twice in such a way as to make several turns in series.
US9556500 — PROCESSES FOR TREATING RED MUD — Orbite Technologies, Inc. (Canada) — There are provided processes for treating red mud. For example, the processes can comprise leaching red mud with HCl so as to obtain a leachate comprising ions of a first metal (for example aluminum) and a solid, and separating said solid from said leachate. Several other metals can be extracted from the leachate (Fe, Ni, Co, Mg, rare earth elements, rare metals, etc.). Various other components can be extracted from solid such as TiO2, SiO2, etc.
US9551078 — ELECTROLYTIC CELL FOR PRODUCING PRIMARY ALUMINUM BY USING INERT ANODE — Aluminum Corporation of China Limited (China) — An electrolytic cell for producing primary aluminum by using inert anodes is disclosed, in which an electrolyte system KF–NaF—AlF3 is used and the operating temperature of the cell is 700-850oC. The electrolytic cell comprises a cell shell, heat insulating refractory lining, a melting pot, a heat insulating cover, inert electrodes, electrode stems, anode bus-bars, cathode bus-bars, anode branching bus-bars, heat insulating plates, partitions between anodes and cathodes and a feeding device. The quality of the aluminum product obtained by using the electrolytic cell is not less than 99.7%. The cell is free from emission of carbon dioxide and perfluorinated compounds (PFCs), and hardly has consumption of electrodes, so the distances between anodes and cathodes can be kept stable. The cell is sealed and the volatilization of dust and fluorides can be prevented, and it is useful to recover oxygen gas.
US9217204 — CONTROL OF TEMPERATURE AND OPERATION OF INERT ELECTRODES DURING PRODUCTION OF ALUMINUM METAL — Norsk Hydro ASA (Norway) — The present invention relates to methods for operating and controlling the temperature of inert electrodes during production of molten aluminum by electrolysis of an aluminous ore, preferably alumina, dissolved in molten salts, preferably a fluoride based electrolyte, in an electrolysis cell with vertical or essentially vertical electrode configuration. The invention describes methods of designing and operating inert electrodes in a vertical and/or inclined position for production of aluminum metal, where said electrodes have an operating temperature that may deviate from the electrolyte temperature, thereby controlling the dissolution of electrode materials and preventing solid deposit formation on the electrodes. The present invention is also applicable to aluminum production cells utilizing inert electrodes in a horizontal configuration, and traditional Hall-Heroult cells retrofitted with inert anodes.
US8992661 — PRODUCTION OF SPECIALTY ALUMINUM ALLOYS USING PARTITION OF FEED IMPURITIES — Tri-Arrows Aluminum Inc. (USA) — A series of inventions leading to the production of specific aluminum alloys (especially aluminum beverage can sheet product) through novel approach of introducing, selectively partitioning and managing alloying elements. This invention also enables manufacturing practices to enhance the performance characteristics of aluminum alloys produced. The selected elements can be derived from carbon anodes made from calcined petroleum coke with high metallic contents (such as nickel and vanadium). Alloying elements can also be introduced and managed from other raw material such as alumina and bath constituents added during aluminum smelting process. Additionally, cell operating parameters, such as cell temperature, off gas flow rate, aluminum tapping rate and impurity partition characteristics can also be manipulated to produce low cost aluminum alloys and facilitate utilization of high metallic content calcined petroleum coke.
US8932050 — SUPPLY MEANS OF A ROTATING FURNACE USED FOR CALCINATION OF OIL GREEN COKE — Petrocoque S/A Industria e Comercio (Brazil) — Calcinated oil coke is an important input used for the production of primary aluminum, intended to carry the electric current for the electrolytic reaction of alumina dissociation for aluminum production. Most of the production of oil calcinated coke in the world is made by rotating furnaces. A system for calcination of oil green coke has a rotating furnace and a rotating cooler, the furnace being serviced by boiler, a combustion chamber and a chimney. There is a feeding system defined by a first mat carrying the green coke into a silo and another mat transporter to feed the furnace. At the end of the silo there are two discharge breadths for the oil green coke, where each breadth has two drawer-like feeders for feeding the green coke onto the mat transporter and, from this to the inside of the rotating furnace through a fall set.
US8651856 — METHOD AND DEVICE FOR HEAT RECOVERY — Innovatherm Prof. Dr. Leisenberg GmbH (Germany) — The present method is used in the manufacture of anodes that are required for electrolytic smelting processes for the production of primary aluminum. A heat recovery method in the manufacture of anodes in an annular anode furnace includes conveying a first partial quantity of the hot air produced in a cooling zone by the waste heat of the anodes into a heating-up zone using a first suction device. A second partial quantity of the hot air produced in the cooling zone is conveyed to a heat exchanger that is realized independently of the annular anode furnace using a second suction device. The heat transfer medium that serves for operating the heat exchanger is primarily heated with the hot air withdrawn from the cooling zone.
US8569565 — PROCESS FOR RECYCLING SPENT POT LININGS (SPL) FROM PRIMARY ALUMINUM PRODUCTION — Befesa Aluminio, S.L. (Spain) — The present invention relates to a process for recycling SPL from primary aluminum production, comprising the steps of grinding the separated fractions or cuts, separating materials by means of mechanical treatment, mixing salt slags with SPL, dissolving in water the product obtained in the previous step, carrying out a chemical reaction between water and the materials to be made inert, sedimenting, removing cyanides, filtering to obtain a soluble fraction and another insoluble fraction, washing the insoluble fraction, crystallizing salts of the soluble fraction and aging or conditioning the insoluble fraction. The present invention further relates to the product obtained by means of said process and the use thereof in different fields of the art.
US8470410 — METHOD AND SYSTEM FOR PRODUCING ELECTROCATALYTIC COATINGS AND ELECTRODES — Institut National de la Recherche Scientifique and National Research Council Canada (Canada) — A method for producing nanostructured coatings on a substrate, comprising: preparing a nanocrystalline powder of a powder size comprised between 1 and 60 .mu.m; and combining cleaning the surface of the substrate and cold spraying the nanocrystalline powder on the surface of the substrate, and a system for producing nanocrystalline coatings on a substrate, comprising a spray head, a cleaning head and a handling system monitoring the spray head and the cleaning head relative to the substrate to be coated, the spray head being a first cold spray head, the first cold spray head depositing on the substrate at least one nanocrystalline powder, the cleaning head optimizing the surface being coated with the at least one layer of nanocrystalline powder.
US8216435 — CALCIUM ALUMINATE CLINKER AS A REFRACTORY AGGREGATE WITH AND WITHOUT BARIUM ADDITION AND USE THEREOF — Westmoreland Advanced Materials, Inc. (USA) — A method of providing a safety lining in an industrial processing container, such as an aluminum electrolytic cell, is provided comprising providing a container having an interior and a at least one primary lining in juxtaposition to said interior of said shell, and adding a calcium aluminate clinker and/or castable layer between the primary lining and the shell of the container. Further, a method of trapping one or more gases, elements or compounds produced from industrial processes is provided using the container having the calcium aluminate layer as herein described. An electrolytic cell is disclosed comprising a shell having an interior, one or more primary linings in juxtaposition to the interior of the shell, and one or more safety linings located between the primary lining and the shell, wherein at least one of the safety linings comprises a calcium aluminate clinker and/or castable.
US7976820 — COMPOSITION AND METHOD FOR IMPROVED ALUMINUM HYDROXIDE PRODUCTION — Nalco Company (USA) — An improved method and composition for producing aluminum hydroxide crystals in a Bayer process pregnant liquor, involve the addition of an emulsified crystallization modifier comprising a C8-C10 fatty acid, precursors, salts or blends thereof. The alkyl chain of the fatty acid crystallization modifier is free of functional groups. The modifier yields a commercially viable product in the presence and absence of a hydrocarbon oil which dissolves the fatty acid. Further, the modifier, prepared in either an emulsified form or as a fatty acid neat, facilitates formation of oxalate aggregates greater than 200 µm which may be readily screened out with minimum trihydrate loss.
US7931737 — SYSTEMS AND METHODS FOR RESTRICTING SCALE IN GAS SCRUBBERS AND RELATED COMPONENTS — Alcoa Inc. (USA) — Systems, methods and apparatus for restricting scale build-up in gas scrubbers and piping are disclosed. The scrubbers and/or pipes may have a coating disposed on internal surfaces thereof. The coating restricts formation of scale within the pipe, especially scale that would normally accumulate due to fluoride-enriched absorbents, such as fluoride-enriched alumina. The coating can be a non-oxide-containing ceramic, a non-metal-containing ceramic, polymer based, carbon based, or a diamond-like carbon coating (e.g., a carbon material containing some amount of sp3 hybridized carbon atoms). The coating has a thickness of 5-15 microns. The coating restricts direct contact between a metal surface of the pipe (e.g., a metal oxide surface) and the transported product(s), restricts adhesion or formation of bonds between a metal surface of the pipe and the transported product(s), and has a sufficiently small surface roughness such that pressure drop through the piping is not significantly affected.
US7879220 — METHOD AND MEANS FOR IMPROVING ELECTROLYSIS CELL OPERATION — Norsk Hydro ASA (Norway) — The present invention relates to a method of improving the current efficiency (CE) in an electrolytic aluminum production cell with an electrolytic bath, at least one anode and at least one cathode, and passing current between said anode and said cathode through said bath and feeding an aluminum containing feedstock to the cell. The CE is improved in that the aluminum containing feedstock is prepared in a manner where it contains substantially no humidity or water before it is fed to the cell, where the electrolytic process is carried out at conditions with reduced amount of hydrogen present.
US7867373 — METHOD AND APPARATUS FOR THE PRODUCTION OF ALUMINUM — Aleris Aluminum Koblenz GmbH (Germany) — Disclosed is a method for the continuous production of aluminum from alumina including a first step of converting alumina (Al2O3) into aluminum sulfide (Al2S3) and a second step of separation of aluminum from aluminum sulfide in a separating reactor. Wherein in the first step in a conversion reactor alumina is dissolved in a molten salt to form a melt and a sulfur containing gas is fed through the melt whereby the sulfur containing gas acts as a reagent to convert at least part of the alumina into aluminum sulfide and at least part of the melt is used in the second step. The separating reactor for the second step is an electrolysis cell. Further the invention relates to an apparatus for operating the method.
US7819937 — USE OF ALUMINA-CARBON AGGLOMERATES IN THE CARBOTHERMIC PRODUCTION OF ALUMINUM — Alcoa Inc. (USA) and Elkem AS (Norway) — An agglomerate comprising alumina, carbon, and a binder for use in a vapor recovery reactor of a carbothermic alumina reduction furnace is disclosed. The alumina-carbon agglomerates may be fed to the vapor recovery reactor, wherein hot aluminum gases will condense on the surface of the colder alumina-carbon agglomerates. In turn, the heat of condensation may be utilized to drive chemical reactions between the materials of the agglomerate and/or the aluminum vapor species that result in the formation of recyclable material (e.g., slag, aluminum carbide). In one approach, a mixed feed material comprising alumina-carbon agglomerates and additional carbon, for example, carbon rings and/or charcoal briquettes, may be used so as to facilitate capture of aluminum vapor species and production of recyclable material. The recyclable material may be added to the main furnace to at least partially assist in the production of aluminum. A method for using alumina-carbon agglomerates to capture aluminum vapor species and utilize waste heat from off-gases in a vapor recovery reactor to form a recyclable material is also disclosed.
US7753988 — USE OF ALUMINA-CARBON AGGLOMERATES IN THE CARBOTHERMIC PRODUCTION OF ALUMINUM — Alcoa Inc. (USA) and Elkem AS (Norway) — An agglomerate comprising alumina, carbon, and a binder for use in a vapor recovery reactor of a carbothermic alumina reduction furnace is disclosed. In one embodiment, the agglomerate has a molar ratio of carbon source to alumina source of at least about 3. In one embodiment, the agglomerate has a molar ratio of carbon source to alumina source of not greater than about 4.5. Thus, the agglomerate may have a molar ratio of carbon source to alumina source in the range of from about 3 to about 4.5. In related embodiments, the weight ratio of alumina source to carbon source is from about 2 to about 2.6. In a particular embodiment, the weight ratio of alumina source to carbon source is about 2.3. A method for using alumina-carbon agglomerates to capture aluminum vapor species and utilize waste heat from off-gases in a vapor recovery reactor to form a recyclable material is also disclosed.
US7556667 — LOW CARBON ALUMINUM PRODUCTION METHOD USING SINGLE FURNACE CARBOTHERMIC REDUCTION OPERATED IN BATCH MODE — Alcoa Inc. (USA) — A batch process for producing low carbon aluminum using a single carbothermic reactor furnace is disclosed in which the slag making, metal making and carbon extraction is carried out in a single furnace, single compartment reactor. This batch process facilitates a more efficient carbothermic aluminum production process. The Al2O and Al vapors generated in slag making and metal making steps are recovered in a vapor recovery reactor, and treated with a carbonaceous material to produce recyclable material comprising Al4C3. The recyclable material is used to assist with one or more subsequent slag making steps.
US7347920 — PRODUCTION, REFINING AND RECYCLING OF LIGHTWEIGHT AND REACTIVE METALS IN IONIC LIQUIDS — The Board of Trustees of the University of Alabama (USA) — Lightweight and reactive metals can be produced from ore, refined from alloy, and recycled from metal matrix composites using electrolysis in electrolytes including an ionic liquid containing a metal chloride at or near room temperature. The electrolysis cell for refining or recycling a metallic element in an anode of the cell, the electrolysis cell comprising a cathode including a porous basket and electrically conductive particles held by the porous basket; an electrolyte comprising 1-methyl-3-methyl imidazolium chloride, 1-ethyl-3-methyl imidazolium chloride, 1-propyl-3-methyl imidazolium chloride or 1-butyl-3-methyl imidazolium chloride and a chloride of the metallic element (e.g. AlCl3); a container holding the cathode and the electrolyte; and an anode comprising the metallic element to be refined or recycled. Low electric energy consumption and pollutant emission, easy operation and low production costs are achieved.
US7255783 — USE OF INFRARED IMAGING TO REDUCE ENERGY CONSUMPTION AND FLUORIDE CONSUMPTION — Alcoa Inc. (USA) — Operations in an electrolytic cell for producing aluminum are controlled by sensing infrared radiation on an outer surface of a cell chamber to determine an actual temperature. When the actual temperature is greater than a target temperature, a crust hole is repaired or the actual rate of addition of aluminum fluoride to the cell is increased. When the actual temperature is less than a target temperature, the actual rate of addition of aluminum fluoride to the cell is reduced.
China Patents
CN106987866 — ALUMINUM ELECTROLYSIS PRE-BAKING CARBON ANODE BAKING METHOD — Aluminum Corporation of China Ltd. (China) — The invention relates to the improvement of an aluminum electrolysis pre-baking carbon anode baking method, in particular to an aluminum electrolysis pre-baking carbon anode baking method. The aluminum electrolysis pre-baking carbon anode baking method is characterized in that the total negative pressure of a smoke discharge frame is controlled to range from 1,800 Pa to 2,400 Pa in the baking process, volatile matter escaping in the green body baking process is effectively and sufficiently combusted, and therefore the temperature of 1P and 2P of a baking furnace is improved; a reasonable baking curve is formulated, so that the temperature increase rate is not larger than 12oC/h, the temperature is kept not decreased in the volatile matter combustion temperature stage, the volatile matter escaping in the green body baking process is effectively and sufficiently combusted, an unified temperature curve is executed through an automatic control system, and flame path material box structures and temperature fields of the baking furnace are kept uniform; and a combustion frame is arranged in a 3P stage in the baking process, and the 3P combustion frame is ignited at the half time of the furnace shift period, so that heat is supplied to be used for combustion of the volatile matter. The actual consumption of baking energy consumption is reduced effectively, and the percent of pass of a pre-baking anode is increased effectively.
CN106978610 — METHOD FOR REDUCING ALUMINUM CELL RADIATION AND GROOVE SMOKE DISCHARGE — Aluminum Corporation of China Ltd. (China) — The invention discloses a method for reducing aluminum cell radiation and groove smoke discharge, and relates to an improvement of a method for reducing prebaked aluminum cell feeding opening radiation and collecting electrolysis reactant gas and electrolyte volatile matter. The method is characterized in that, at the position of a discharging opening where an aluminum cell anode break joint and an electrolytic cell middle joint are crossed and a non-discharging position, an aluminum oxide discharging pipe and an electrolytic reaction gas and electrolyte volatile matter air guide pipe are arranged correspondingly; and the upper end of the discharging pipe is connected with an aluminum oxide constant volume discharging device, and an upper port of the air guide pipe is connected with an electrolytic cell horizontal smoke pipe. By means of the method, aluminum oxide discharging can be guaranteed, the anode effect is reduced, and the collecting and purifying efficiency of electrolytic reaction gas and electrolyte volatile matter is improved; and an opened fire eye does not exist, electrolytic cell radiating is reduced, and a good environmental protection and energy saving effect is achieved.
CN106868549 — CONNECTED TYPE AUXILIARY FLUE PIPE FOR ALUMINUM ELECTROLYSIS — China Aluminum International Engineering Corp. (China) — The invention relates to a connected type auxiliary flue pipe, in particular to a connected type unpowered auxiliary flue pipe for an aluminum electrolysis system flue gas purification system. The connected type auxiliary flue pipe for the aluminum electrolysis comprises electrolytic cells and auxiliary flue pipe branch pipes each connected with one electrolytic cell. Each auxiliary flue pipe branch pipe communicates with the corresponding auxiliary flue pipe branch. The adjacent auxiliary flue pipe branches communicate with each other and are gathered into corresponding auxiliary fuel pipe main pipes. The connected type auxiliary flue pipe has the beneficial effects that the flue exhaust negative pressure of the auxiliary flue pipe can be increased, accordingly the flue exhaust amount of the electrolysis cell auxiliary flue pipe is increased by 1-2 times, the flue exhaust amount of the electrolysis cells in the cover opening work can instantaneously reach 2-5 times the normal design exhaust amount, and the higher airtight efficiency and the higher environmental protection indexes are achieved.
CN106834686 — URANIUM REMOVING PROCESS FOR GALLIUM PRODUCTION PROCESS — Aluminum Corp. of China Ltd. and Beijing Research Institute of Uranium Geology (China) — The invention belongs to the technical field of radioactive element recovery, and particularly relates to a uranium removing process for a gallium production process. The uranium removing process comprises the following steps: adding ferrous sulfate salt or reduced iron powder in a sulfuric acid desorption solution of gallium, stirring for dissolving, and then regulating the solution with sodium hydroxide to be alkaline; adding sodium sulfide, stirring for dissolving, standing and precipitating; recovering a liquid part after solid-liquid separation, and taking a solid part as uranium containing tailings; adding concentrated sulphuric acid in the recovered liquid to regulate the solution to be acidic; obtaining solid gallium mud after solid-liquid separation; adding a sodium hydroxide solution in the gallium mud to obtain a gallium mud dissolved solution; and obtaining coarse gallium through electrolysis. By adoption of the uranium removing process, the technical problem of relatively low gallium recovery rate of a uranium removing process in an existing gallium production process is solved, the purity and the quality of a gallium product are remarkably improved, and the gallium recovery rate is effectively increased.
CN106830026 — HIGH PRESSURE DIGESTION METHOD FOR ALUMINUM OXIDE PRODUCTION — China Aluminum International Engineering Corp. (China) — The invention relates to a high-pressure digestion method for aluminum oxide production in the field of aluminum oxide production. The high-pressure digestion method for aluminum oxide production includes feeding raw ore pulp into two groups of digestion and heat exchange sleeves by high-pressure diaphragm pumps, reaching a digestion temperature through steam exhaust by flashing, live steam condensed water preheating and live steam heating, reacting in a stopping tube to digest, and feeding the ore pulp into a diluting tank in a red mud separation and washing process after undergoing flashing of a group of flash tanks. The high-pressure digestion method for aluminum oxide production has the advantages that the problems that an existing domestic aluminum oxide factory is low in digestion temperature and relative digestion rate, adverse to decomposition due to high digestion liquor molecular ratio, high in consumption index, large in occupied area, difficult to overhaul and high in investment and energy consumption are mainly solved; the consumption indexes such as ores and steam can be decreased, and occupied area, investment and electricity consumption in operation are reduced; washing liquid flows into an after-diluting tank automatically directly, so that a primary washing liquid pump in the high-pressure digestion process is omitted; flow and power of a diluting pump are reduced, and investment and energy consumption are lowered.
CN106756139 — METHOD FOR MAKING A GRAPHITE ROTOR BY USING WASTE GRAPHITE CATHODES FROM ALUMINUM ELECTROLYSIS BATHS — Shenyang University of Chemical Technology (China) — The invention provides a method for preparing a graphite rotor by using waste graphite cathodes of aluminum electrolysis baths and relates to a method for preparing an oxidation-resistant and wear-resistant graphite rotor. The invention relates to electrolytic aluminum and aluminum alloy smelting processing and particularly relates to the recycling of electrolytic aluminum waste cathode materials and the manufacture of the oxidation-resistant and wear-resistant high-performance graphite rotor. Waste electrolysis bath cathodes are cut into different sizes of blocks, and after being selected, are soaked in an acid solution rich in oxygen. Metal impurities and CN- in the waste cathodes are removed, the waste cathodes are washed clean by using water, dried and then machined, and the graphite rotor is prepared. By utilizing the waste graphite cathodes of the aluminum electrolysis baths to prepare the graphite rotor, the stacking problem of the waste cathodes is solved, precious graphite resources in China are protected, and the service life of the graphite rotor is prolonged.
CN106629606 — METHOD FOR SEPARATING FLUORIDE SALT AND CARBON IN ALUMINUM ELECTROLYSIS CARBON RESIDUES — Aluminum Corp. of China Ltd. (China) — The invention discloses a method for separating fluoride salt and carbon in aluminum electrolysis carbon residues, relates to a method for treating anode carbon residues generated in an aluminum electrolysis process, and in particular relates to a method for recycling fluoride salt and carbon in the anode carbon residues. The method is characterized by comprising the following steps: separating fluoride salt and carbon in carbon residues in the separation process by adopting a vacuum distillation furnace, condensing and collecting the fluoride salt on the upper part of the vacuum distillation furnace, and collecting the reaction carbon residues on the lower part of the vacuum distillation furnace. According to the method disclosed by the invention, the fluoride salt separation effect is good, the separated fluoride salt is low in impurity content and can directly return to an electrolytic cell, the content of carbon in the rest carbon residues is greatly improved, the carbon can be returned to a carbon plant for utilization and the fluoride salt and carbon in the aluminum electrolysis carbon residues can be efficiently recycled.
CN106591889 — PREPARATION METHOD FOR MAGNALIUM Al-Mg ALLOY — China Enfi Engineering Corp. (China) — The invention provides a preparation method for magnalium, an Al-Mg alloy. The method comprises the following steps that a magnesium salt and aluminum salt mixed raw material is prepared according to the mass ratio of magnesium to aluminum in the magnalium to be prepared; and the mixed raw material is subjected to molten salt electrolysis codeposition, the relative error between the faraday electric quantity required for discharging of magnesium ions and aluminum ions in the mixed raw material and the electrolysis electric quantity for electrolysis of the mixed raw material during molten salt electrolysis codeposition is controlled at +/-15%, and the magnalium is obtained. Through the preparation method and the molten salt electrolysis codeposition mode, the matching consistency between the faraday electric quantity required for discharging of the magnesium ions and the aluminum ions and the electrolysis electric quantity during electrolysis is controlled, the relative error between the Faraday electric quantity and the electrolysis electric quantity is controlled to be within at +/-15%, the contents of the two metallic components in the magnalium product are consistent with target contents, and accordingly the components of the magnalium are effectively controlled. Furthermore, the magnalium is prepared through the preparation method.
CN106517209 — METHOD FOR TREATING SPENT CATHODES OF SPENT POTLININGS OF ALUMINUM ELECTROLYSIS CELLS — Aluminum Corp. of China Ltd. (China) — The invention relates to a method for resource utilization of solid wastes of aluminum electrolysis cells, in particular to a method for treating spent cathodes of spent potlinings of aluminum electrolysis cells. The method includes adding a carbon material and quartz sand into the spent cathodes of the spent potlinings of the aluminum electrolysis cells, conducting high-temperature carbothermic reduction in a high-temperature reacting furnace to obtain SiC, enabling cryolite to form melts to sink, making the melts and the generated SiC to undergo solid-liquid separation, and subjecting a fluoride salt to furnace gas evaporation prior to gas-solid separation from the generated SiC so as to obtain SiC; collecting the sunk cryolite melts and conducting condensation recovery so as to obtain cryolite; collecting evaporated furnace gas and cooling so as to obtain the fluoride salt. The method has the advantages that the SiC is prepared through a high-temperature carbothermic reduction method, fluoride and electrolytes are recovered, the electrolytes are reused for the aluminum electrolysis industry, and cyanide in the spent potlinings is decomposed and removed, so that comprehensive resource utilization of the spent potlinings of the aluminum electrolysis cells is achieved and electrolysis production cost is reduced.
CN106319573 — CHARGING METHOD FOR ALUMINUM OXIDE IN AN ALUMINUM ELECTROLYSIS CELL — Aluminum Corp. of China Ltd. (China) — The invention provides a charging method for aluminum oxide in an aluminum electrolysis cell and relates to charging method for aluminum oxide in a process of preparing aluminum through molten salt electrolysis. The method is characterized in that the aluminum oxide passes through a constant volume blanker and then directly enters into an electrolysis cell through a high temperature resistance metal pipe. According to the charging method provided by the invention, the aluminum oxide passes through the constant volume blanker and then directly enters into the electrolysis cell through the high temperature resistance metal pipe, a shell-striking hammer device is not used and the problem of blocking of the hammer and the charging can be thoroughly solved. A layer of anti-electrolyte sticky material is respectively arranged on the inner and outer surfaces of the high temperature resistance metal pipe; the continuous or intermittent vibration can be realized in the manner of pneumatic power, ultrasonic wave, and the like; an ultrasonic method is preferably selected; the method is realized through an ultrasonic wave generating system arranged on the electrolysis cell. The charging method provided by the invention can be used for replacing a current used shell-striking charging method on a prebaked cell, so that the aluminum oxide charging efficiency can be increased, the blocking problem can be thoroughly solved, the anode effect can be reduced, the greenhouse gas emission can be reduced, and the labor work load can be relieved.
CN105586607 — METHOD OF USING SPENT CATHODES — Aluminum Corp. of China Ltd. (China) — The invention provides a method of using spent cathodes, and relates to integration of an aluminum electrolysis cell and the spent cathodes, in particular to a method for utilizing the spent cathodes as raw materials of cathode carbon blocks for aluminum. The method of using the spent cathodes is characterized in that according to a process, the spent cathodes which are eliminated from the aluminum electrolysis cell when the aluminum electrolysis cell is stopped and overhauled are roughly pulverized, precisely pulverized, screened and sorted to obtain carbon particles and electrolyte particles in the spent cathodes, wherein the carbon particles are used for producing the raw materials of the cathode carbon blocks for aluminum, and the electrolyte particles are returned to an aluminum electrolysis production process. According to this method of using spent cathodes, the spent cathodes are roughly pulverized and precisely pulverized, a color selector and a photoelectric technology are adopted, special-color particles in the spent cathode particles are automatically sorted out according to difference of colors of materials, so that a carbon part and an electrolyte part in the spent cathodes are separated from each other effectively, a carbon material is used for replacing part of cathode producing raw materials (electrically calcined anthracite), comprehensive utilization ratio is high, and the cost for production of the cathode carbon blocks for aluminum can be reduced effectively.
CN105568319 — METHOD FOR TESTING INSTANTANEOUS CURRENT EFFICIENCY OF ALUMINUM CELL — Aluminum Corp. of China Ltd. (China) — The invention relates to a method for testing the instantaneous current efficiency of an aluminum cell and relates to an improvement on the method for testing the instantaneous current efficiency of the aluminum cell during an aluminum electrolysis production process. The testing process of the method comprises the following steps in sequence: (1), adopting an Orsat gas apparatus to test the content of the anode gas CO2 of the aluminum cell; (2), adopting the Orsat gas apparatus to test the content of anode gas O2 of the aluminum cell; (3), adopting the Orsat gas apparatus to test the content of the anode gas CO of the aluminum cell; and (4), counting the instantaneous current efficiency of the aluminum cell by counting the volume percentage of the anode gas CO2 in the total volume of CO2 and CO through using a CO2/CO analytical method. The method provided by the invention is simple to operate, and solves the problem of air dilution caused by adopting the CO2/CO analytical method for testing current efficiency, the error between the testing result and the true value is smaller than 0.5 percent, and the instantaneous current efficiency of the aluminum cell can be quickly tested in time.
CN105543504 — METHOD FOR EXTRACTING LITHIUM SALT FROM ALUMINUM ELECTROLYTE BY UTILIZING FLUORIDE ROASTING AND ACID LEACHING — Northeastern University (China) — The invention discloses a method for extracting lithium salt from aluminum electrolyte by utilizing fluoride roasting and acid leaching, and belongs to the technical field of inorganic chemistry. The method comprises the following steps: step 1: mixing materials; and step 2: carrying out fluoride roasting; and step (3): (1) carrying out acid leaching and filtering to obtain primary filtrate and primary filtered substances; (2) respectively treating the primary filtrate and the primary filtered substances to obtain secondary filtrate and secondary filtered substances; (3) respectively treating the secondary filtrate and the secondary filtered substances to obtain tertiary filtrate and tertiary filtered substances; and (4) respectively treating the tertiary filtrate and the tertiary filtered substances. According to the method disclosed by the invention, an element lithium in the electrolyte can be effectively extracted, so that energy consumption for electrolytic aluminum production is reduced; lithium carbonate chemical raw materials with a high additional value are recycled, and the used raw materials are common raw materials in the chemical field, so that the comprehensive average extraction cost is relatively low; various substances can be separated out, and the obtained substances are relatively high in purity; and the lithium element influence problem is solved for the aluminum electrolysis industry, benefits are increased, and the overall level of the aluminum electrolysis industry in China is improved.
CN105420495 — URANIUM SEPARATION METHOD DURING GALLIUM TREATMENT IN ALUMINUM OXIDE PRODUCTION THROUGH BAYER PROCESS — Aluminum Corp. of China Ltd. and Beijing Research Institute of Uranium Geology (China) — The invention discloses a uranium separation method during gallium treatment in aluminum oxide production through a Bayer process. The uranium separation method comprises the following steps that A, the pH of a special-effect resin acid desorption solution of gallium is controlled to be 1-3; B, a neutralization solution in the step A is made to flow through a pretreated anion exchange resin column, and a column passing solution is separated; C, the column passing solution is neutralized through sodium hydroxide till the pH value reaches 5-9, deposited gallium mud is obtained, the gallium mud is dissolved through alkali liquor, the gallium mud dissolved liquid is obtained, quick lime is added into the dissolved liquid, vanadium is removed through sedimentation, heavy metal in the solution is removed, electrolysis is conducted, and crude gallium products are obtained; D, the anion exchange resin column is subjected to cleaning and impurity removal through diluted acid, and uranium is eluted through acid nitrate or acid chloride; and E, sodium hydroxide is added into the uranium-contained water phase, the pH of the solution is adjusted to be 7-9, sodium diuranate sedimentation is generated, and crude uranium products are obtained after filtering and separation. The uranium separation method is designed according to different characteristics of uranium and gallium, uranium-gallium separation is achieved, and uranium can be recycled.
CN105369290 — METHOD FOR PRODUCING PREBAKED ANODE CAPABLE OF LOWERED AIR PERMEABILITY — Aluminum Corp. of China Ltd. (China) — The invention discloses a method for producing a prebaked anode capable of lowering air permeability and relates to the improvement of the production technology of prebaked anodes for aluminum electrolysis. The method for producing the prebaked anode capable of lowering the air permeability is characterized by comprising the steps that (1) screening is conducted after calcinations, and screened fine coke powder is subjected to fine grinding again; (2) anode scrap ingredients are added, wherein the diameters of broken anode scraps are 5-15 mm, and the actual density of the broken anode scrapes is larger than 1.55 g/cm3; and (3) the specific gravity of green bodies after vibration forming is larger than or equal to 1.64 g/cm3. According to the method, calcined coke is partially subjected to fine grinding again, so that the adding and filling performance of the calcined coke is improved, the broken anode scrap diameter and the actual density of the anode scrap ingredients are controlled, the quality of the green bodies is effectively guaranteed, the technical problem that the air permeability in the production of the prebaked anode fluctuates and is high is solved, and the quality of the prebaked anode is improved. The average value of the air permeability of the produced anode is lowered to 0.9 npm from 2.6 npm, and the standard deviation is lowered to 0.4 from 1.863, so that the air permeability of the prebaked anode is greatly reduced.
CN105369289 — DEVICE FOR REDUCING RADIATION FROM THE SHELL OF AN ALUMINIUM ELECTROLYSIS CELL — Aluminum Corp. of China Ltd. (China) — The invention provides a device for reducing radiation from the shell of an aluminum electrolysis cell, and relates to the device for reducing radiation of the side portion shell of an aluminum electrolysis cell in the aluminum electrolysis production process. The device for reducing the radiation from the aluminum electrolysis cell shell is characterized by structurally positioning a fixing plate which is a vertical plate matched with a cell shell housing between aluminum electrolysis cell edge plates and cathode bars in shape, and an airflow baffle plate which is a horizontal plate fixedly connected with the fixing plate. According to the device for reducing radiation of the aluminum electrolysis cell shell, the purpose of reducing radiation of the aluminum electrolysis cell shell is achieved by resisting convection and/or radiating effect of the air around the aluminum electrolysis cell; the device is convenient to disassemble and move, simple in structure, good in heat insulation effect, and convenient to operate. The device can effectively lower the convection coefficient and/or the radiating coefficient of the air around the aluminum electrolysis cell, reduces radiation from the aluminum electrolysis cell shell, and is beneficial to low-energy consumption and stable operation of the aluminum electrolysis cell.
CN105350024 — ONLINE GROOVE DEVICE FOR MEASURING THE THICKNESS OF AN ALUMINUM ELECTROLYSIS ANODE CELL — Aluminum Corp. of China Ltd. (China) — The invention relates to an online groove measuring device for the thickness of an aluminum electrolysis anode in the aluminum electrolysis production process, in particular to an online groove measuring device for the thickness of the aluminum electrolysis anode. The online groove measuring device is characterized by structurally comprising a device support, a measuring marker post and a universal meter; the support structurally comprises a vertical operation rod, a lower horizontal arm lever and an upper horizontal arm lever, the end of the lower horizontal arm lever is fixed to the lower end of a vertical frame rod, the end of the upper horizontal arm lever is fixed to the upper portion of the vertical frame lever, and the upper horizontal arm lever is located in the same direction with the lower horizontal arm lever; the measuring marker post is a height measuring rod with scales, and the measuring marker rod is in vertical sliding connection with the tail end of the upper horizontal arm lever of the device support; and one end of the universal meter is connected with the upper end of the measuring marker post. According to the online groove measuring device for the thickness of the aluminum electrolysis anode, the thickness of the anode of an aluminum electrolysis groove can be measured online, the consumption of the anode is grasped in real time, and reasonable usage of the anode is guaranteed; and operation is simple and fast, accuracy is high, the service time of the anode can be accurately determined, the unit consumption of the aluminum electrolysis anode is reduced, and cost is saved.
CN105274562 — ALUMINUM AND SILICON ELECTROLYTIC SEPARATION METHOD FOR ALUMINUM-SILICON ALLOY — State Grid Corp. of China, Economic Technology Research Institute of State Grid Jibei Electric Power Co. Ltd., and North China University of Technology (China) — The invention discloses an aluminum and silicon electrolytic separation method for an aluminum-silicon alloy. The aluminum and silicon electrolytic separation method comprises the following specific steps: (1) an electrolyte solution is prepared, namely a proper amount of phosphoric acid, oxalic acid and boric acid are taken to be gradually dissolved in deionized water, a proper amount of glycerin is added into the dissolved solution and the electrolyte solution is prepared; (2) electrolytic separation is conducted, namely the aluminum-silicon alloy is taken as an anode, stainless steel is taken as a cathode, constant-current electrolysis is conducted, and the anode enriched anode slime is silica powder; and (3) postprocessing is conducted, namely the anode enriched silica power is subjected to acid pickling to remove impurities, washing by deionized water, filtering and drying, and silicon higher in purity is obtained. The purity of the finally obtained silicon power is more than 90%.
CN105256332 — PRE-BAKING ANODE FOR ALUMINUM ELECTROLYSIS AND ALUMINUM ELECTROLYSIS CELL — ChinaHunan Chuangyuan Aluminum Industry Co. Ltd. (China) — The invention provides a pre-braking anode for aluminum electrolysis. The pre-baking anode comprises an anode body, wherein the anode body comprises a slot which is formed by sinking towards the top surface of the anode body from the bottom surface of the anode body; the slot is arranged along a diagonal line on the bottom surface of the anode body, and is open in two ends; and the slot is 10-20mm wide and 100-450mm high. Compared with the prior art, the pre-baking anode has the beneficial effects that: the bottom voltage drop of the aluminum electrolysis cell is relatively low, energy consumption is effectively reduced, and slot condition stability is high.
CN105088282 — ALUMINUM ELECTROLYSIS FLUE GAS PURIFICATION SYSTEM AND METHOD FOR CONTROLLING FEEDING CHANNELS OF ALUMINUM ELECTROLYSIS FLUE GAS PURIFICATION SYSTEM — China Hunan Chuangyuan Aluminum Industry Co. Ltd. (China) — The invention discloses an aluminum electrolysis flue gas purification system. The aluminum electrolysis flue gas purification system comprises a main feeding channel and further comprises a crown block feeding channel, a standby feeding channel and a high-pressure air hose communicated with the standby feeding channel. The inlet end of the standby feeding channel is communicated with the crown block feeding channel. The outlet end of the standby feeding channel is communicated with a discharge port of the main feeding channel. The main feeding channel comprises an impeller feeding machine. The high-pressure air hose is provided with a control switch electrically connected with the impeller feeding machine. The control switch can be switched to the turn-on state or the turn-off state according to whether the work parameter of the impeller feeding machine exceeds a set threshold or not so that the standby feeding channel can be started for use or closed. According to the flue gas purification system, when the main feeding channel is blocked, the standby feeding channel is started, the using amount of aluminum fluoride is reduced, influences of pollutants containing fluorine on ecology can be reduced, and the compounding effect of an electrolytic tank can be avoided. The invention further discloses a method for controlling the feeding channels of the aluminum electrolysis flue gas purification system.
CN104928718 — ELECTROLYSIS CELL PRODUCTION PROCESS — China Hunan Chuangyuan Aluminium Industry Co. Ltd. (China) — The invention provides an aluminum electrolysis cell production process including normal-period management and abnormal-period management; the abnormal-period management is divided into starting initial-period management and starting final-period management. The invention discloses a feeding method for aluminum oxide continuous feeding and parameters thereof, and discloses parameter values in electrolyte height control, electrolyte composition control, melt height control, and voltage management of the starting final-period management in the abnormal-period management of electrolysis cell production. Compared with the related technology, with use of the electrolysis cell production process, the fluctuation range of an aluminum oxide concentration value is small, and the problems that occur due to relatively high feeding of the single-time aluminum oxide quantity, a part of alumina is too late to dissolve, sinks into liquid aluminum or a furnace bottom and is stacked on a cathode, as a result that, the cathode resistance is increased, the cathode voltage drop is increased and electrolysis energy consumption is increased are solved. Therefore, the current efficiency is improved, furnace bottom precipitates are reduced, the furnace bottom voltage drop is reduced, and energy consumption is saved.
Editor’s Note: A portion of the patents listed here first appeared in the February 2018 issue of Light Metal Age. To read more articles and news from this issue, please subscribe.