389 results about "Hydrogen oxidation" patented technology

The invention provides a dump leaching method for improving the leaching rate of gold ore, and belongs to the technical field of mineral processing. The method comprises the following steps: firstly, separating minerals into oversize products and undersize products; mixing sodium carboxymethyl cellulose, bentonite and ferrous sulfate to obtain a mixture, and granulating the undersize product by using the mixture as a binder; and mixing the undersize product particles with the oversize product, and carrying out cyanide-free dump leaching. According to the method, through graded granulation and heap building, the problem that heap building permeability is poor due to the fact that the gold ore contains many clay minerals is solved. In the granulation stage, ferrous hydroxide colloid generated by hydrolysis of ferrous sulfate in the binder can assist ore particle agglomeration, and particle stability is enhanced; during subsequent cyanide-free dump leaching, ferrous sulfate can be used as an auxiliary reducing agent and a catalyst in a thiourea gold leaching system to promote oxidation and dissolution of gold; meanwhile, ferrous ions can adjust the oxidation-reduction potential of a system, so that the thiourea gold leaching reaction is in a more favorable potential interval, the oxidation efficiency of thiourea is improved, invalid decomposition of thiourea is reduced, and therefore the use amount of thiourea and the use amount of agents are reduced.

The invention relates to a dephosphorization material, a preparation method thereof and a dephosphorization method, belongs to the field of water treatment, and solves at least one of the problems of contradiction between adsorption capacity and structural stability, fast capacity fading, short service life, difficult recovery, higher cost and the like of the existing lanthanum-based dephosphorization material. The phosphorus removal material is a nano-porous carbon-supported lanthanum composite material, and comprises an amorphous nano-porous carbon matrix, an amorphous nano-porous carbon carrier, an amorphous nano-porous carbon carrier, and an amorphous nano-porous carbon carrier, and an active component embedded in situ in the nanoporous carbon matrix; wherein the active component comprises lanthanum oxide and / or lanthanum hydroxide. According to the invention, the adsorption capacity is high, the structure is stable, the attenuation of the adsorption capacity is delayed, the service life is prolonged, the cost is reduced, and the adsorbent can be recycled.

The invention discloses a method for preparing a sulfur-doped nickel hydroxide-based self-supporting electrolyzed water anode, and belongs to the technical field of preparation of electrolyzed water catalytic electrodes, and the method comprises the following steps: S1, preparing strong oxidizing salt, thiourea and transition metal salt into an active solution; s2, pretreating the nickel-containing metal substrate to obtain a precursor; and S3, immersing the precursor in an active solution for ultrasonic impregnation, and performing in-situ oxidation to prepare the sulfur-doped nickel hydroxide-based self-supporting electrolytic water anode. According to the method for preparing the sulfur-doped nickel hydroxide-based self-supporting electrolytic water anode, an oxidizing agent-thiourea-transition metal salt synergistic reaction system is adopted, an ultrasonic-assisted technology is combined, and a high-performance catalytic layer is directly grown on the surface of the metal substrate in situ at room temperature; the invention aims to synchronously realize high catalytic activity, excellent stability and macro preparation of the electrode and fundamentally solve the core pain points of long process, high energy consumption, difficulty in amplification and the like in the prior art.

The invention belongs to the field of PET (polyethylene glycol terephthalate) plastic waste treatment, and particularly relates to preparation of a copper oxide-nickel hydroxide core-shell structure catalytic material and application of the copper oxide-nickel hydroxide core-shell structure catalytic material to preparation of high-added-value formic acid by upgrading electro-catalysis PET plastics, and the preparation method comprises the following steps: (1) placing a copper conductive substrate in an alkali etching mixed solution for alkali etching treatment, obtaining a conductive substrate on which a Cu (OH) 2 precursor grows; (2) placing the conductive substrate on which the Cu (OH) 2 precursor grows in a muffle furnace for heat treatment to obtain a conductive substrate on which CuO nanowires grow; and (3) placing the conductive substrate on which the CuO nanowire grows in a hydrothermal kettle, and obtaining the CuO-coated Ni (OH) 2-x core-shell structure catalyst through a hydrothermal method.

A hybrid electrochemical device configuration that comprises a first electrode that includes a redox reactive material or an alloy based on a transition metal, a second electrode that includes a multi-functional catalyst to catalyze hydrogen evolution reaction, hydrogen oxidation reaction, and water oxidation reaction at the second electrode, a separator disposed between the first and second electrode, an electrolyte disposed between the first electrode and the second electrode, and a conduit which provides the means to compensate for water loss in the electrolyte during electrochemical device operation. At least one valve is included that connects the electrolyte management system to the conduit system and a valve to connect the gas formed in the electrode to the gas management system. The electrochemical device configurations include several individual devices stacked on top of each other and separated from each other using separation plates.

The invention relates to the field of preparation of nano materials, in particular to a preparation method of a metal-oxide cluster electro-catalytic material based on an ammonia-mediated electrostatic adsorption principle, and aims to solve the problem that a metal-oxide cluster heterogeneous interface is difficult to accurately construct by an existing method. The preparation method comprises the following steps: dispersing a carbon carrier, a soluble inorganic compound containing platinum, ruthenium and rhodium, a soluble metal complex anion salt and dopamine hydrochloride in a water-alcohol mixed solution, adding ammonia water, and preparing a metal-oxide heterogeneous cluster precursor through an ammonia-mediated electrostatic adsorption effect; and pyrolyzing the precursor in a reducing atmosphere to prepare the metal-oxide cluster electro-catalytic material. The prepared electro-catalytic material has a definite heterogeneous cluster interface and has excellent performance in alkaline hydroxide reaction. The method is simple and convenient to operate, low in cost and low in energy consumption, can be popularized to various metal-oxide cluster electro-catalytic materials, and has application potential.

The invention belongs to the technical field of anion exchange membrane fuel cells, and discloses a high-stability ruthenium-based hydroxide electrocatalyst used as an anode of an anion exchange membrane fuel cell and a preparation method of the high-stability ruthenium-based hydroxide electrocatalyst. The catalyst is prepared by taking ruthenium as a unique active component, fullerene (C60) as a carbon substrate and polydopamine (PDA) as an additive through argon heat treatment. The preparation method disclosed by the invention is simple and easy to implement, and through the design scheme that C60 with high electron affinity is used as a carrier, the electronic structure of a ruthenium active site is effectively adjusted, and excessive adsorption of a ruthenium-based catalyst to hydroxyl species in a hydrogen oxidation reaction (HOR) process is weakened, so that the ruthenium reaction active site is greatly reserved for hydrogen adsorption, and the hydrogen adsorption efficiency is improved. Therefore, the stability of ruthenium-based electro-catalysis in hydrogen oxidation reaction can be greatly improved.

The invention provides a method for extracting tantalum and niobium from tungsten tailings, and belongs to the technical field of rare metal recovery, and the method comprises the following steps: adding a reducing agent, a fluxing agent, a covering agent and a slag former into the tungsten tailings, and heating and smelting under the protection of inert gas to obtain an alloy ingot; the alloy ingot is crushed and then leached through hydrochloric acid, and acid leaching residues containing tantalum, niobium and tungsten are obtained; the acid leaching residues are subjected to alkaline leaching, and alkaline leaching residues containing tantalum and niobium are obtained; the alkaline leaching residues are leached through hydrofluoric acid and sulfuric acid, and decomposition liquid is obtained; and extracting and separating the decomposition liquid to obtain tantalum hydroxide and niobium hydroxide, and respectively calcining the tantalum hydroxide and niobium hydroxide to obtain tantalum oxide and niobium oxide. The method is simple in technological process, convenient to operate, low in cost and suitable for industrial production, tantalum and niobium can be efficiently extracted from tungsten tailings, and good economic benefits and environmental benefits are achieved.

Provided here are methods for producing a shaped metal-supported catalyst. One such method includes the steps of mixing a support hydroxide with an aqueous mixture of an active metal compound to form a malleable mixture of an active metal incorporated support hydroxide, passing the malleable mixture through a molding device to produce a shaped metal-supported wet catalyst; and drying and calcining the shaped metal-supported wet catalyst. The support hydroxide contains one or more of aluminium hydroxide, silica hydroxide, zirconia hydroxide, cerium hydroxide, titanium hydroxide, lanthanum hydroxide, gallium hydroxide, or niobium hydroxide. The active metal compound can be one or more of vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, and rhenium.

The invention belongs to the technical field of hydrogen production by electrocatalytic decomposition of water, and provides an iron-doped nickel hydroxide composite iron-doped cerium oxide electrocatalyst and application thereof in electrolyzed water. The iron-doped nickel hydroxide composite iron-doped cerium oxide electrocatalyst comprises a nickel substrate, wherein a porous catalytic activity layer of three-dimensional flower-shaped spherical nanoparticles formed by stacking two-dimensional nanosheets is loaded on the surface of the nickel substrate. The catalytic active layer comprises an iron-doped hexagonal stacked nickel hydroxide structure, the catalytic active layer comprises an iron-doped cubic stacked cerium oxide structure, and no iron with a crystalline structure exists in the catalytic active layer. The iron-doped nickel hydroxide composite iron-doped cerium oxide electrocatalyst disclosed by the invention shows excellent oxygen evolution performance in an oxygen evolution reaction of electrocatalytic water decomposition.

The invention relates to the technical field of electro-catalytic material synthesis, and particularly discloses a tower-shaped nickel hydroxide catalytic material and a preparation method thereof. The preparation method of the tower-shaped nickel hydroxide catalytic material comprises the following steps: (1) surface treatment of a nickel substrate: performing ultrasonic cleaning treatment on the nickel substrate, and performing vacuum drying to obtain the cleaned nickel substrate; and (2) synthesis of tower-shaped nickel hydroxide: dissolving phosphate to obtain a phosphate solution, adding hydrogen peroxide, stirring, adding the cleaned nickel substrate, and carrying out hydrothermal reaction to obtain a semi-finished product of tower-shaped nickel hydroxide. And (3) cleaning and drying the tower-shaped nickel hydroxide: cleaning the semi-finished product tower-shaped nickel hydroxide, and carrying out vacuum drying to obtain the tower-shaped nickel hydroxide catalytic material. The method is simple in process, relatively low in cost and easy for large-scale synthesis, and has a relatively good large-scale commercial application prospect; and the specific morphology effectively exposes active crystal faces and active sites, and as an excellent catalyst, the catalyst can improve the hydrogen production rate and the organic matter oxidation rate.

Methods and apparatuses for converting carbon dioxide to useful compounds are disclosed. The method involves reducing bicarbonate solution in an electrolyzer. Bicarbonate solution is supplied to the cathode. The direct reduction of bicarbonate at the cathode may be coupled with an oxidation reaction at the anode. The oxidation reaction may provide a source of protons (H+) to cathode for the reduction of bicarbonate. The oxidation reaction may be a hydrogen oxidation reaction (HOR). Hydrogen gas (H2) may be supplied to the anode. In some embodiments, a source of gas may be supplied to the bicarbonate solution to form a pressurized solution before supplying the solution to the cathode.

This invention relates to a hydrogen-form ZSM-48 molecular sieve, its synthesis method, and its applications. The hydrogen-form ZSM-48 molecular sieve has an average mesopore size of 6 nm to 30 nm, a B / L acid ratio of 0.7 to 3.4, and a specific surface area of ​​100 m². 2 / g~500m 2 / g. The synthesis method of the hydrogen-form ZSM-48 molecular sieve includes the following steps: (1) Under contact conditions, silicon source, aluminum source, template agent and water are mixed evenly to obtain a gel; (2) The gel obtained in step (1) is subjected to hydrothermal crystallization treatment, and then washed, dried and calcined to obtain hydrogen-form ZSM-48 molecular sieve. The template agent in step (1) includes hexamethylammonium hydroxide and urea; preferably, the template agent also includes urease. The synthesis method controls the molecular sieve pore size and B / L acid ratio by introducing urease and using a two-stage hydrothermal treatment method, thereby realizing the control of molecular sieve properties according to the target reaction characteristics, which is beneficial to improving the yield of low-branched isoalkanes and improving the quality of lubricating oil base oil.

The application discloses a preparation method of a nickel-doped and high-hydrated cobalt-chromium-iron ore monocrystal under high temperature and high pressure, and the method comprises the following steps: preparing a cylindrical cobalt-chromium-iron ore sample by taking solid basic cobalt carbonate powder, solid chromium (III) acetate hydroxide crystal powder, solid nickel stearate, solid oxalic acid powder, solid chromium hydroxide powder, solid nickel hydroxide powder and liquid dilute nitric acid as starting raw materials; preparing water source sheets by taking chromium hydroxide powder and nickel hydroxide powder in a weight ratio of 4:1; placing two water source sheets at two ends of the cylindrical cobalt-chromium-iron ore sample respectively and then putting them into a double-capsule structure sample bin; and obtaining a cobalt-chromium-iron ore monocrystal after high-temperature and high-pressure reaction, so that the blank of the preparation technology of the nickel-doped and high-hydrated cobalt-chromium-iron ore large-grain monocrystal under the current high-temperature and high-pressure condition is solved, and the experimental sample of the nickel-doped and high-hydrated cobalt-chromium-iron ore large-grain monocrystal is obtained.

This invention discloses a platinum-based catalyst for the hydrogenation reaction, its preparation method, and an electrode. The catalyst uses orthorhombic niobium pentoxide (T-Nb₂O₅) as a support to support the active component platinum. The support is resistant to strong acids and electrochemical corrosion at potentials above 1.0 V (vs RHE). The catalyst exhibits a hydrogenation reaction current density of not less than 200 mA·cm⁻¹ at 0.45 V (vs RHE). ‑2 In preparation, ammonium niobate oxalate hydrate was used as the niobium source, and the mixture was gelled via a sol-gel method. The gel was then heat-treated at 600-700℃ to obtain an orthorhombic niobium pentoxide support. The pH was adjusted to less than 3, and platinum was reduced with sodium borohydride to prepare the catalyst. This catalyst was then used to fabricate a hydrogen depolarization anolyte gas diffusion electrode with a platinum loading of 0.5-1.0 mg·cm³. ‑2 It can operate continuously and stably for no less than 120 hours with a cell voltage in the range of 1.25-1.45V. The catalyst of this invention has high activity and excellent stability, and can be used as a hydrogen depolarization anode in hydrometallurgy, significantly reducing electrolysis energy consumption and making it suitable for industrial applications.

The invention discloses a preparation method of high-purity Nb2O5, belongs to the field of preparation of Nb2O5, and solves the problem of low purity of Nb2O5 prepared by the existing method. The preparation method comprises the steps that a metal niobium ingot with the purity larger than or equal to 99.999% is adopted, and vacuum drying is conducted after surface peeling, dilute nitric acid ultrasonic cleaning and high-purity water flushing are conducted; the pretreated niobium ingot is subjected to a hydrogenation reaction in a pure hydrogen atmosphere, niobium hydride is generated and then crushed, and niobium hydride powder is obtained; carrying out dehydrogenation treatment on the niobium hydride powder under a high vacuum condition; dissolving the metal niobium powder with electronic-grade hydrofluoric acid, and filtering to obtain fluorine niobic acid filtrate; performing multi-stage counter-current extraction and reverse extraction on the fluobiobic acid filtrate by adopting an extracting agent to obtain fluobiobic acid reverse extraction liquid; introducing high-purity ammonia gas into the fluobiobic acid strip liquor, and precipitating to generate niobium hydroxide; ageing, filtering and washing with high-purity water for multiple times to obtain a niobium hydroxide filter cake; and calcining the niobium hydroxide filter cake in a high-purity oxygen atmosphere in stages to obtain niobium pentoxide. The niobium pentoxide prepared by the method disclosed by the invention is high in purity.

The invention provides a ferromanganese oxide and a preparation method and application thereof, and belongs to the technical field of secondary batteries. The molecular formula of the ferromanganese oxide is MnxFeyAaBbO3, A is tetravalent metal, B is divalent metal, 0.19 < = x < = 1.8, 0.19 < = y < = 1.8, 0 < = a < = 0.1, 0 < = b < = 0.1, 1.9 < = x + y + 3 / 2a + 3b < = 2.1, and primary particles of the ferromanganese oxide are sheet-shaped. The ferromanganese oxide provided by the invention is of a sheet structure, and more active sites can be provided to support efficient electrochemical reaction, so that the electrochemical performance of the positive electrode material prepared by taking the ferromanganese oxide as the precursor is improved. According to the preparation method of the ferromanganese oxide, part of the ferrous hydroxide precipitate is dissolved under the overalkaline condition, so that the coprecipitation effect is achieved, and the use of a complexing agent is avoided.

The invention discloses a method for recovering a titanium dioxide byproduct ferrous sulfate. The method comprises the following steps: S1, dissolving a titanium dioxide byproduct ferrous sulfate in water, and filtering to obtain a first filtrate; s2, adjusting the pH value of the first filtrate to 4.5-5.5, and filtering to obtain a second filtrate; s3, adding sulfide into the second filtrate, and filtering after reaction to obtain third filtrate; s4, adding an alkaline liquid into the third filtrate, and filtering after reaction to obtain a fourth filtrate and a first filter cake, so as to obtain ferrous hydroxide with first purity; and S5, preparing ferrous oxalate dihydrate from the ferrous hydroxide with the first purity. According to the method, through the synergistic effect of accurate pH value control, sulfide impurity removal and fractional precipitation, efficient separation of iron and manganese is achieved, the complex impurity removal process of multiple oxidation reduction is avoided, the operation process is simple, ferrous oxalate dihydrate is prepared after high-purity ferrous hydroxide is prepared, and the impurity removal cost is low.

This invention discloses a method for preparing tin dioxide powder by freeze-drying to inhibit tin hydroxide agglomeration. The method involves adding a tin source solution (36-54 g / L) and a precipitant solution (5-30 g / L) at a mass ratio of 1:0.1-0.25 under constant temperature and magnetic stirring. The precipitant solution is then added dropwise to the tin source solution, reacting to form tin hydroxide colloid. After static aging, the colloid undergoes rapid cryogenic freezing to instantly freeze it into an ice state. The ice-state colloid is then subjected to low-temperature vacuum sublimation drying to obtain loose tin hydroxide dry powder. The dry powder is then calcined to obtain tin dioxide powder. This invention fundamentally eliminates the agglomeration of tin dioxide powder, resulting in tin hydroxide dry powder with an agglomeration rate of less than 10% and a purity of over 99.9%, providing a high-quality precursor for high-performance electronic-grade tin dioxide.

This invention provides a method for producing high-purity aluminum-niobium-tantalum master alloys and co-producing ammonium fluoride, belonging to the fields of metallic materials and inorganic chemicals. The invention involves mixing fluoroniobic acid, fluorotantalic acid, and ammonia water for a precipitation reaction to obtain a precipitate and an ammonium fluoride solution. The ammonium fluoride solution is then concentrated, cooled for crystallization, dehydrated, and dried sequentially to obtain ammonium fluoride. The precipitate is then dried and oxidized and calcined sequentially to obtain an oxide. The oxide, aluminum powder, potassium chlorate, and calcium fluoride are mixed and subjected to a vacuum aluminothermic reaction to obtain the high-purity aluminum-niobium-tantalum master alloy. This invention, considering both broadening the range of raw material selection and optimizing the production process, reacts fluoroniobic acid, fluorotantalic acid, and ammonia water to produce niobium hydroxide and tantalum hydroxide precipitates, which are then oxidized and calcined to form niobium and tantalum oxides. The high-purity aluminum-niobium-tantalum alloy is then prepared using a vacuum aluminothermic reaction. Simultaneously, ammonium fluoride can be co-produced, resulting in high raw material utilization.

This invention discloses a proton exchange membrane hydrogen pump anode and its application. The anode includes an anode sheet and a catalyst composited on the anode sheet. The catalyst includes a support and a first metal and a second metal composited on the support. The first metal is selected from one or more of platinum, iridium, palladium, and ruthenium; the second metal is selected from one or more of iron, cobalt, nickel, molybdenum, and vanadium. The first metal serves as the main active center for the hydrogen oxidation reaction, and the second metal can regulate the electronic structure of the first metal, thereby reducing the adsorption of carbon monoxide at the active site or promoting its oxidative removal. The synergistic effect of the two metals allows the anode containing the catalyst to maintain high hydrogen oxidation activity and stability in hydrogen fuel containing carbon monoxide, thereby improving the carbon monoxide poisoning resistance of the proton exchange membrane hydrogen pump containing the anode.

The invention belongs to the technical field of hydrogen fuel cells, and particularly relates to an anode catalyst layer applied to a fuel cell and a preparation method and application of the anode catalyst layer. The anode catalyst layer for the fuel cell comprises a water electrolysis layer and a hydroxide layer which are overlapped, and the hydroxide layer is in contact with a proton exchange membrane of the fuel cell; the water electrolysis layer comprises a water electrolysis catalyst, carbon powder and first perfluorinated sulfonic acid resin; the hydroxide layer comprises a hydroxide reaction catalyst and second perfluorinated sulfonic acid resin; the ion exchange equivalent EW1 of the first perfluorinated sulfonic acid resin is less than or equal to the ion exchange equivalent EW2 of the second perfluorinated sulfonic acid resin. The anode catalyst layer for the fuel cell has the beneficial effects that through the gradient design of the hydrophilic and hydrophobic properties of the water electrolysis layer and the hydroxide layer, the antipole resistance of the anode catalyst layer is remarkably improved, the performance attenuation degree after antipole is reduced, and the service life of the fuel cell is prolonged.

This invention discloses a Se-doped Pt-based catalyst, its preparation method, and its application, relating to the field of catalyst technology. The preparation method of the Se-doped Pt-based catalyst includes the following steps: (1) mixing conductive carbon black and selenium dioxide powder uniformly to obtain a mixture; (2) heating the mixture to 250-350℃ under an inert atmosphere and holding for 0.5-2 h; (3) subsequently heating to 950-1100℃ and holding for 0.5-2 h to obtain powder A; (4) dissolving a platinum source in water to obtain solution B, then adding powder A to solution B and mixing uniformly, followed by rotary evaporation, grinding, and heating in a mixed atmosphere of H2 and Ar to obtain the Se-doped Pt-based catalyst. The Se-doped Pt-based catalyst prepared by the method of this invention exhibits high catalytic activity and stability in the hydrogenation reaction.

The present application relates to non-ferrous metal technical field, specifically to a kind of method for preparing large bulk density of tantalum pentoxide by chemical method, comprising the following steps: (1) adjust acid;(2) heating;(3) heating after fluorotantalate solution is passed into ammonia;(4) second stage ammonia precipitation;(5) static washing;(6) drying, obtain dry tantalum hydroxide;(7) push boat furnace roasting, obtain large bulk density of tantalum pentoxide.The present application uses static continuous washing, without through physical filter pressing, change physical performance parameter.The present application uses push boat furnace static continuous roasting, and the bulk density of tantalum pentoxide grows naturally.The powder of the present application is loose and uniform after roasting, without screening.The present application can efficiently produce the tantalum pentoxide with bulk density greater than 2g / cm 3 .

The present invention provides a method for selectively leaching and removing impurities from nickel and cobalt hydroxide. The method comprises: slurrying nickel and cobalt hydroxide raw materials, then sequentially adding acid and nickel and cobalt hydroxide to adjust the pH value, and obtaining a pre-leached liquid and a pre-leached residue after leaching; slurrying the pre-leached residue, then sequentially adding acid, a reducing agent, and nickel and cobalt hydroxide to obtain a first leachate and a first leach residue after leaching; slurrying the first leach residue, then adding acid, and obtaining a second leachate and a second leach residue after leaching; wherein the second leachate contains copper ions, iron ions, and aluminum ions; mixing the second leachate with a pH adjusting agent, and obtaining a third leachate and a third leach residue after leaching; wherein the third leach residue contains iron and aluminum elements; mixing the third leachate with acid, then adding a copper reducing agent to carry out a reduction reaction, and obtaining a fourth leachate and a fourth leach residue after leaching. This method can improve efficiency and save costs.

To provide a method for producing a new ferrite quantum dot different from a conventional one.SOLUTION: A method for producing ferrite quantum dots, the method comprising the steps of preparing a mixed solution in which at least ferrous hydroxide is present in water at 0 °C or higher and 30 °C or lower, preparing a green rust-containing suspension by oxidizing the mixed solution to form green rust crystals in the mixed solution, synthesizing ferrite quantum dots in the suspension by raising the temperature of the suspension to 50 °C or higher and 100 °C or lower in an oxygen-free stream, and collecting the ferrite quantum dots in the suspension.SELECTED DRAWING: None

A nickel-hydrogen secondary battery (2) comprises an outer can (10) and an electrode group (22) housed in the outer can (10) together with an alkaline electrolyte. The electrode group (22) is formed by overlapping a positive electrode (24) containing a positive electrode mixture and a negative electrode (26) containing a negative electrode mixture via a separator (28). The positive electrode mixture comprises nickel hydroxide solid-dissolved with zinc as a positive electrode active material and zinc oxide as a positive electrode additive. The negative electrode mixture comprises hydrogen storage alloy particles and a negative electrode additive. The negative electrode additive is a composite of yttrium fluoride loaded on carbon black, and the composite covers a portion of the surface of the hydrogen storage alloy particles.

This invention belongs to the field of secondary utilization technology of metal resources, specifically relating to a method for treating waste liquid from electroplating zinc-nickel alloys. The method includes the following steps: S1, mixing the waste liquid from electroplating zinc-nickel alloys, oxygen, and a catalyst, and performing an oxidation reaction to obtain an intermediate liquid and nitrogen; the oxidation reaction temperature is ≥220℃; S2, adjusting the pH of the intermediate liquid to 13.0-13.5, performing a first filtration separation to obtain nickel hydroxide sludge and filtrate 1; S3, adjusting the pH of filtrate 1, performing a second filtration separation to obtain zinc hydroxide sludge and filtrate 2. This invention first degrades COD to obtain zinc and nickel ions; adjusting a specific pH value generates nickel hydroxide sludge, with zinc ions existing in the system as polyhydroxy zinc anions, achieving separation of nickel and zinc; further adjusting the pH separates zinc from the system as zinc hydroxide sludge precipitate. The operation is simple, with high separation efficiency and high purity.

The invention discloses a method for preparing aluminum-doped nickel hydroxide through hydrothermal synthesis and application, belongs to the technical field of battery materials, and provides an alkaline environment in a mode of thermal decomposition of hexamethylenetetramine so as to prepare the aluminum-doped nickel hydroxide with nano flower-shaped morphology through a hydrothermal method. The prepared aluminum-doped nickel hydroxide is lattice-doped alpha-phase nickel hydroxide, when the aluminum doping amount is 11%, the discharge duration is prolonged by 42% compared with that of undoped nickel hydroxide, and the aluminum-doped nickel hydroxide has the electrochemical performance and structural stability obviously superior to those of beta-phase nickel hydroxide and has higher specific capacity and better electrochemical reaction activity. The method is suitable for preparing the aluminum-doped nickel hydroxide, and is used for preparing an aluminum-doped nickel hydroxide electrode and a nickel-iron battery.

Disclosed is a metal element recovery method which comprises: a step (1) for obtaining an acidic first solution by dissolving a metal in a crushed product of a lithium ion battery in an acidic aqueous solution; a step (2) for changing divalent iron ions in the first solution to trivalent iron ions; a step (3) for obtaining a second solution and a first precipitate that contains an iron compound or the like by adjusting the pH of the first solution to fall within the range of 3.0 to 5.0; a step (4) for obtaining a third solution and a second precipitate that contains copper sulfide by adding a sulfurizing agent to the second solution and adjusting the pH of the second solution to fall within the range of 4.0 to 5.0; a step (5) for obtaining a fourth solution and a third precipitate that contains nickel hydroxide or the like by adjusting the pH of the third solution to fall within the range of 7.0 to 8.5; and a step (6) for obtaining a fifth solution and a fourth precipitate that contains a lithium compound by concentrating the fourth solution while injecting a carbon dioxide gas thereinto.