231 results about "Nickel hydroxide (II)" patented technology

The invention provides a method for precipitating nickel and cobalt in a solution containing nickel and cobalt and a cobalt nickel hydroxide product. The method comprises the following steps: step S100, carrying out a seed crystal pretreatment reaction on a nickel-cobalt-containing solution by adopting first nickel-cobalt precipitation underflow to form pretreated nickel-cobalt ore pulp; step S200, adding an alkaline precipitation inducer into the second nickel-cobalt precipitation underflow or the first nickel-cobalt precipitation overflow to carry out alkali conversion reaction to form alkali conversion crystal mush; s300, the pretreated nickel-cobalt ore pulp and alkali conversion crystal mush are continuously introduced into a reactor for a nickel-cobalt precipitation reaction, and nickel-cobalt precipitated ore pulp is obtained; step S400, continuously performing dense separation treatment on the ore pulp subjected to nickel-cobalt precipitation; s500, the third nickel-cobalt precipitation underflow is filtered and washed in sequence, a nickel-cobalt hydroxide product is obtained, and the problems that in the prior art, when nickel and cobalt are precipitated through a nickel-cobalt-containing solution, MHP is small in particle size and not prone to sedimentation, the water content of a filter cake is high, or the precipitation rate is poor, and the magnesium content is high before technical improvement are solved.

The invention provides an MHP precipitation method based on a compound alkali precipitator and application of the MHP precipitation method, and the MHP precipitation method comprises the following steps: mixing laterite-nickel ore iron and aluminum removed liquid and a compound alkali solution for precipitation reaction to obtain cobalt nickel hydroxide slurry; the compound alkali in the compound alkali solution comprises a mixture of sodium carbonate and sodium hydroxide; and carrying out post-treatment on the cobalt nickel hydroxide slurry, and separating to obtain the MHP. According to the method, a sodium hydroxide and sodium carbonate compounded system is used as a precipitator, the MHP is prepared under the cooperation of sodium carbonate and sodium hydroxide, the content of manganese in the obtained MHP is remarkably reduced, the content of nickel and cobalt in the MHP is increased, the method has important significance for reducing the cost for preparing crystals through subsequent MHP refining, meanwhile, the reaction rate is more controllable, the obtained MHP is better in filtering performance, and the method is suitable for industrial production. The water content is lower.

The invention belongs to the field of battery materials, and discloses a high-entropy high-nickel positive electrode material which comprises a base material LiNixCoyMzO2, a base further comprises a lithium-site doping element and a nickel-site doping element, the surface of the base is coated with an island-shaped coating layer, and the island-shaped coating layer is a nano metal oxide layer. The preparation method comprises the following steps: uniformly mixing a high-nickel hydroxide precursor, a lithium source, a compound containing an element A and a compound containing an element B, carrying out two-stage sintering, mixing with a metal oxide containing an element C and a metal oxide containing an element D, and sintering to obtain the high-entropy high-nickel positive electrode material. Lithium doping in a bulk phase of the high-entropy high-nickel positive electrode material can improve the electronic conductivity of a single crystal material, increase the interlayer spacing of transition metal and inhibit lithium and nickel positive ions from being mixed, and nickel doping can improve the structural stability and thermal stability of the material, inhibit irreversible phase change of H2-H3 and stabilize lattice oxygen of the material; the doping modification of the two sites further improves the performance of the material.

The invention discloses a nickel-containing etching wastewater treatment process, which belongs to the technical field of environmental protection, and comprises a raw water regulating tank, a pH pre-regulating tank, a heterogeneous catalytic oxidation tower, a neutralization coagulation tank, an inclined tube sedimentation tank and a clean water tank which are connected in sequence. According to the process, under the neutral condition, a catalyst loaded with cobalt manganese oxide is used for activating sodium hydrogen persulfate, high-activity sulfate free radicals are generated, a Ni-EDTA complex structure is fractured in a targeted mode, free nickel ions are released in situ, organic ligands are synchronously mineralized, and the adding amount of sodium hydrogen persulfate is dynamically adjusted through a clean water pool closed-loop control system; and high-purity nickel hydroxide precipitate is generated through alkaline precipitation and coagulation, so that efficient solid-liquid separation is realized. The treatment process disclosed by the invention is compact in flow and stable in operation, effectively solves the problems of difficult complex breaking, low nickel removal efficiency, high sludge toxicity, difficult resource recovery and the like when the EDTA complex nickel wastewater is treated by a traditional method, realizes closed-loop recovery of nickel resources, and has the remarkable advantages of low cost, high efficiency and environmental friendliness.

The invention provides an impurity removal and recovery method of electrodeposited nickel anolyte, which comprises the following steps: (1) mixing the electrodeposited nickel anolyte with liquid caustic soda, carrying out solid-liquid separation to obtain nickel hydroxide and filtrate, and evaporating the filtrate to obtain sodium sulfate; mixing the electrodeposited nickel anolyte with a nickel source to obtain a mixed solution; (2) mixing the mixed solution with barium salt, and carrying out lead removal treatment; (3) adjusting the pH value of a material obtained after lead removal treatment by using nickel hydroxide to obtain a solution to be subjected to arsenic removal, and mixing the solution to be subjected to arsenic removal with polyferric sulfate for arsenic removal treatment; and (4) a material obtained after arsenic removal treatment is mixed with an oxidizing agent, a solution to be subjected to iron removal is obtained, solid-liquid separation treatment is conducted on the solution to be subjected to iron removal, catholyte with lead, arsenic and iron removed and iron-containing slag are obtained, sodium sulfate is supplemented into the catholyte with lead, arsenic and iron removed, and the catholyte is reused in the nickel electrodeposition process. According to the method, lead, arsenic and iron in the electrodeposited nickel anolyte can be efficiently and rapidly removed and recycled.

The invention discloses a method for controlling ion concentration and volume balance in an electrolyte by using nickel hydroxide. The method comprises the following steps: preparing a reaction base solution containing a first complexing agent and a first alkali; the first anolyte, a second complexing agent solution and a second alkali solution are simultaneously added to the bottom of the reaction base solution for stirring reaction, solid-liquid separation is performed after nickel hydroxide reaches the target particle size, and filtrate and a filter cake are obtained; washing the filter cake, and slurrying the filter cake by using a second anolyte to obtain a nickel hydroxide slurrying material; and adjusting the sodium ion concentration, pH and nickel ion concentration of the third anolyte by adopting a sodium hydroxide solution, a nickel hydroxide slurrying material and a nickel sulfate solution to obtain the catholyte. According to the invention, a feeding mode of feeding at the bottom is adopted, and a complexing agent is matched, so that crystals can stably grow and are convenient to filter; in the preparation process, aging and too high pH conditions are not needed, operation is simpler, labor intensity is small, the reaction rate is higher, and continuous treatment of the anolyte can be achieved.

The invention provides a wet treatment process for laterite-nickel ore. The wet treatment process comprises the following steps: S1, carrying out acid leaching treatment on the laterite-nickel ore by adopting inorganic acid to obtain leached ore pulp; s2, the leached ore pulp is sequentially subjected to liquid-solid separation and countercurrent washing, and washed pulp and leached residues are obtained; s3, a first oxidizing agent and a first neutralizing agent are added into the washed slurry for iron and aluminum removal treatment, and a solution with iron and aluminum removed and iron and aluminum slag are obtained; s4, carrying out nickel and cobalt precipitation treatment on the solution subjected to iron and aluminum removal, so as to obtain precipitated slurry; s5, continuously carrying out dense separation treatment on the precipitated slurry to obtain underflow and overflow; and S6, the underflow is subjected to washing aftertreatment in sequence, and a cobalt nickel hydroxide product is obtained. The invention provides a short-process wet treatment process for laterite-nickel ore, the production cost and energy consumption are reduced, and meanwhile, the recovery rate of nickel and cobalt, the overall recovery rate of scandium and the quality of nickel-cobalt oxide products are improved.

The invention discloses a process for treating nickel wastewater containing nickel acetate cleaning water and nickel acetate concentrated water, which comprises the following steps: S1, filtering nickel wastewater, S2, carrying out primary concentration treatment, S3, carrying out secondary concentration treatment, S4, treating by a sodium metaaluminate method, S5, carrying out collaborative filtration treatment, and S6, discharging RO (Reverse Osmosis) produced water up to the standard. The method comprises the following steps: primarily enriching nickel ions by adopting primary nickel concentration treatment and secondary nickel concentration treatment, adding a sodium metaaluminate solution into a mixed solution, enabling the pH value of the mixed solution to be 8-12, enabling the nickel ions to react with hydroxyl ions to generate a nickel hydroxide precipitate, adding a sulfuric acid solution to adjust the pH value of the mixed solution back to 6.5-7.5, hydrolyzing sodium metaaluminate to generate an aluminum hydroxide precipitate, and carrying out secondary nickel concentration treatment on the aluminum hydroxide precipitate; aluminum hydroxide adsorbs nickel hydroxide to form a composite precipitate, aluminum ions and nickel ions are subjected to a competitive complexation reaction, and a flocculating agent is added into a mixed solution to form a flocculent precipitate, so that the reaction time is short, the nickel content in the nickel sludge can be greatly increased, the treatment period can be shortened, and the operation cost can be reduced.

The invention relates to a preparation method of a multi-site silver (Ag) and nickel hydroxide (Ni (OH) 2) modified copper (Cu) nanowire catalyst (Ag-Ni (OH) 2) / Cu NW) and application of the multi-site silver (Ag) and nickel hydroxide (Ni (OH) 2) modified copper (Cu) nanowire catalyst. A cation exchange and electrodeposition method is adopted to prepare an electrocatalytic nitrate reduction reaction NO3-RR series catalyst with three sites of Ag, Ni (OH) 2 and Cu. Based on the synergistic effect of three sites, Ag in the catalyst promotes conversion from nitrate NO3 <-> to nitrite NO2 <->, Ni (OH) 2 promotes dissociation of water H2O to generate free hydrogen * H, Cu atoms near Ni (OH) 2 accelerate conversion from NO2 <-> to ammonia NH3, and the efficient series catalytic process is achieved. Under the condition of-0.1 V vs. Reversible hydrogen electrode RHE in a 1M potassium hydroxide solution containing 50 mM of potassium nitrate, the NH3 yield of 4.01 mgh <-1 > cm <-2 > and the NH3 Faraday efficiency of 97.3% are obtained, under the condition of 0V vs. RHE, the excellent energy efficiency of 46.5% is achieved, the excellent catalytic activity is kept in a NO3 <-> solution with the wide concentration, and the good sewage treatment capacity is achieved. The invention provides a new design thought for tandem catalysis, and has a wide application prospect in the field of NO3-RR.

The application discloses a composite precipitant for wet refining of laterite nickel ore and a wet refining method of laterite nickel ore. The composite precipitant for wet refining of laterite nickel ore is composed of a mixture of magnesium oxide and sodium hydroxide, and the mass fraction of sodium hydroxide in the composite precipitant is greater than 0 and less than or equal to 99%. The wet refining method of laterite nickel ore comprises the following steps: directly or after being grinded, the composite precipitant is added into an acidic solution to be refined, and stirring is performed to make the composite precipitant fully react with the acidic solution to be refined; after concentration, a clear liquid and a solid-containing slurry are obtained; the solid-containing slurry is filtered and washed with water to obtain a solid containing nickel hydroxide, cobalt hydroxide or nickel hydroxide-cobalt hydroxide, so that nickel, cobalt or nickel-cobalt is precipitated. The composite precipitant and the wet refining method of laterite nickel ore have the advantages of simple process, low cost, easy process control, easy settlement and filtration of nickel hydroxide (and cobalt hydroxide) precipitation, and the production efficiency can be significantly improved and the energy consumption can be reduced.

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 provides a gas sensor and a method for preparing the gas sensor through laser direct writing. The method comprises the following steps: enabling a metal electrode to be in contact with laser direct writing ink, wherein the laser direct writing ink comprises a nickel source, a porous structure guiding agent and a solvent; laser irradiates a specified contact area of the metal electrode and the laser direct-writing ink, so that the metal electrode absorbs the laser to generate heat so as to form a hydrothermal reaction area in the specified contact area, and the laser direct-writing ink in the hydrothermal reaction area is subjected to a hydrothermal reaction, so that porous nickel hydroxide grows on the metal electrode, and a precursor structure is obtained; and carrying out annealing treatment on the precursor structure so as to convert the porous nickel hydroxide into porous nickel oxide, thereby obtaining the gas sensor. The gas sensor provided by the invention has the porous nickel oxide which has a relatively large specific surface area, so that the effective contact area between the gas sensor and target gas can be increased, and the gas responsivity of the gas sensor is improved.

The present invention provides a nickel smelting method which includes: (A-i) a reduction heat treatment process of heat-treating a first raw material containing nickel and lithium; (B) a first leaching process of leaching a heat treatment product generated by the reduction heat treatment process; (A-ii) a roasting process of heat-treating a second raw material containing nickel and sulfur; (C) a second leaching process of leaching a first leaching residue generated by the first leaching process and a calcine generated by the roasting process; (D) a neutralization process of neutralizing a second leached solution generated by the second leaching process; (E) a purification process of removing impurities contained in a neutralized solution generated by the neutralization process; and (F) a precipitation process of performing a precipitation method for recovering nickel from a purified solution generated by the purification process, wherein nickel hydroxide is recovered by the precipitation process.

The invention relates to an anode catalyst capable of being updated in situ in an electrolytic bath as well as a preparation method and application of the anode catalyst. The anode catalyst capable of being updated in situ in the electrolytic bath comprises a nickel-based self-supporting carrier and a NiFe-LDH nanosheet array S-NiFe-LDH which is loaded on the nickel-based self-supporting carrier and formed by alternately combining S element doped nickel hydroxide and ferric hydroxide.

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.

The invention relates to an efficient and stable electrode material and a preparation method thereof.The preparation method comprises the steps that a nickel net substrate is pretreated, then an electroplating solution containing a nickel source and a pore forming agent is prepared, a layered nickel hydroxide layer is generated on the substrate through electro-deposition, then ions enter the nickel hydroxide layer through a soaking embedding method or an electrochemical embedding method, and the electrode material is obtained. And finally, sintering in a nitrogen atmosphere, controlling the sintering temperature, the sintering time and the heating and cooling rate, and performing cooling after-treatment to obtain the electrode material. Compared with the prior art, the catalytic performance and the stability of the electrode are optimized through the steps of ion embedding and sintering. The method is suitable for preparing an electrode for efficient water electrolysis reaction, a porous structure promotes rapid emission of gas and increases the active surface area, and ions embedded in the surface are used for forming a shell with high catalytic activity.

The invention discloses a method for deeply removing arsenic from a nickel sulfate solution, which comprises the following steps: adjusting the pH value by using nickel hydroxide to form colloid to preliminarily remove arsenic, oxidizing by using sodium sulfate, and adding polyferric sulfate to form ferric hydroxide colloid to deeply adsorb and remove arsenic, and is simple in process, convenient to implement in the production process, capable of greatly reducing the cost and reducing the environmental pollution, and suitable for industrial production. The method comprises the following steps: adjusting the pH value of a low-pH leaching solution / anolyte / crude nickel sulfate dissolving solution to 4.0 or more by using nickel hydroxide, carrying out filter pressing to remove slag, adding arsenic ions in a sodium persulfate oxidation solution, reacting for 30 minutes, adding polyferric sulfate, reacting for 30 minutes, and carrying out filter pressing to obtain a nickel sulfate solution which is almost free of arsenic, and the method is efficient, safe and environment-friendly.

The invention provides a method for improving main components in a cobalt nickel hydroxide intermediate product. The lifting method comprises the following steps: step S100, carrying out first activation on cobalt nickel hydroxide intermediate product slurry by adopting an alkaline substance to obtain first activated product slurry; step S200, adjusting the solid content of the first activated product slurry; s300, activating the first activated product slurry for the second time by adopting a reducing agent to obtain second activated product slurry; step S400, adjusting the solid content of the second activated product slurry; and step S500, adding the second activated product slurry into a nickel-cobalt-containing solution for conversion reaction to obtain nickel cobalt hydroxide and a converted solution. According to the method disclosed by the invention, the total content of nickel and cobalt in cobalt nickel hydroxide can be remarkably increased and reaches a level exceeding 50%. The problems that the content of impurities such as magnesium and manganese in the nickel cobalt hydroxide intermediate product is too high, the content of sulfate radicals is too high, and consequently the subsequent refining production cost is increased are solved.

The invention provides chlorine-doped nickel oxide, a preparation method and application thereof and a photoelectric device, and relates to the field of photoelectric materials.The preparation method of the chlorine-doped nickel oxide comprises the following steps that S10, an aqueous solution of nickel salt and chlorine salt is obtained, an alkaline solution is dropwise added, centrifugation is conducted, and a coprecipitate is obtained; s20, washing, drying and roasting the coprecipitate to obtain chlorine-doped nickel oxide; wherein the molar ratio of the nickel salt to the chlorine salt is (10-20): (1-4). In the technical scheme provided by the invention, the nickel salt and the chlorine salt are co-precipitated to generate a co-precipitate of nickel hydroxide and chloride, and then the co-precipitate is washed, dried and roasted to prepare the chlorine-doped nickel oxide, so that the hole mobility of the chlorine-doped nickel oxide is improved; the alkaline solution is dropwise added for coprecipitation, so that the particle size of the coprecipitate can be reduced, and the nanoscale chlorine-doped nickel oxide is prepared, so that the dispersity of the chlorine-doped nickel oxide in a mobile phase is improved, and the chlorine-doped nickel oxide can be applied to preparation of a hole transport film and improvement of the uniformity of the hole transport film.

The invention provides a doubling treatment method of battery black powder and nickel cobalt hydroxide. The doubling treatment method comprises the following steps: carrying out reduction roasting and water immersion treatment on the battery black powder to obtain a first lithium-containing liquid and a solid product; carrying out acid leaching on the solid product to obtain a leaching solution; after removing impurities from the leachate, extracting the leachate with a first saponification extraction agent to obtain first raffinate and a first extraction organic phase; carrying out soap conversion reaction on the first raffinate and a second saponification extraction agent to obtain a second extracted and soap-converted organic phase and a second lithium-containing liquid; carrying out acid leaching and impurity removal on nickel cobalt hydroxide, and carrying out extraction reaction on the solution and the second extraction soap-converted organic phase to obtain a second extraction organic phase and a second raffinate; the second raffinate is subjected to Co extraction, Mg extraction and evaporative crystallization, and nickel sulfate is obtained; and the organic phase obtained after Co extraction is subjected to back extraction and evaporative crystallization, and cobalt sulfate is obtained. Compared with a traditional doubling treatment technology, the doubling treatment method avoids the problem of impurity pollution caused by doubling treatment of traditional battery black powder and nickel cobalt hydroxide raw materials.

The invention discloses a NiMoO4 / Ni (OH) 2 (at) NiPx layered structure catalyst as well as a preparation method and application of the NiMoO4 / Ni (OH) 2 (at) NiPx layered structure catalyst. The preparation method of the catalyst comprises the following steps: step 1, cleaning the nickel substrate; step 2, synthesizing a nickel molybdate (NiMoO4) precursor on the nickel substrate through a hydrothermal method; and step 3, growing a nickel hydroxide and nickel phosphide compound (Ni (OH) 2 and NiPx) on the surface of NiMoO4 through an electro-deposition method. The catalyst has a three-dimensional layered structure, a one-dimensional NiMoO4 micron / nanorod is used as a support, a two-dimensional Ni (OH) 2 nanosheet grows on the surface of NiMoO4, and zero-dimensional NiPx nanoparticles are embedded on the Ni (OH) 2 nanosheet. The catalyst shows excellent performance in hydrogen evolution reaction, has high activity and good stability, and is suitable for clean hydrogen production.

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 discloses a preparation method and application of a Ni3S2-Ni (OH) 2 heterostructure nanosheet catalyst, Ni (OH) 2 is grown in situ on a foamed nickel substrate by using a hydrothermal method, and hydroxyl anions in a nickel hydroxide nanosheet array are partially replaced by active sulfur anions released by sodium sulfide through anion exchange reaction to form Ni3S2-Ni (OH) 2 heterostructure nanosheets. According to the catalyst prepared by the method, due to the graded porous structure of the foamed nickel, rapid diffusion of ions is effectively ensured; the ultrathin nanosheet structure provides a relatively large electrochemical active area, and more active sites are exposed; the heterostructure formed by sulfur doping adjusts the electronic structure of the catalyst, reduces the energy barrier of surface reconstruction, significantly improves the catalytic activity of the material, can be used as a catalytic electrode in electrochemical ammoxidation reaction, and effectively improves the ammonia decomposition efficiency.

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.

The invention discloses an electrochemical preparation method and application of a superfine platinum particle modified nickel-iron double hydroxide nanosheet array, and belongs to the technical field of water electrolysis. The preparation method comprises the following steps: in a three-electrode system, taking a mixed solution of nickel salt and ferrous salt as an electrolyte, and carrying out electro-deposition by adopting a constant potential deposition method to obtain a carbon cloth material for in-situ growth of a ferro-nickel hydroxide nanosheet array; and then in a two-electrode system, a mixed solution of chloroplatinic acid and potassium hydroxide is used as an electrolyte, and electro-deposition is performed by adopting a constant current deposition method, so that uniform loading of superfine platinum particles on the surface of the ferro-nickel double hydroxide nanosheet array is realized. The superfine platinum particle modified nickel-iron double hydroxide nanosheet array prepared by the preparation method disclosed by the invention can show excellent catalytic activity and stability in hydrogen production by alkaline electrolysis of water.

The invention relates to an MHP precipitation method based on a compound alkali precipitator, which comprises the following steps: adding a compound alkali solution into a laterite-nickel ore liquid after iron and aluminum are removed, and carrying out precipitation reaction to obtain cobalt nickel hydroxide slurry; the compound alkali in the compound alkali solution comprises a mixture of sodium carbonate and sodium hydroxide; and carrying out post-treatment separation on the cobalt nickel hydroxide slurry to obtain the MHP. According to the method, a sodium hydroxide and sodium carbonate compounded system is used as a precipitator, and the MHP is prepared under the cooperation of sodium carbonate and sodium hydroxide, so that the problem of local over-alkalinity caused by direct use of strong-alkalinity sodium hydroxide is solved, the content of manganese in the obtained MHP is reduced, the content of nickel and cobalt in the MHP is increased, and the cost of subsequent MHP refining for preparing crystals is conveniently reduced; meanwhile, the reaction rate is more controllable, and the obtained MHP is better in filterability and lower in water content.

The invention discloses a method for removing calcium and magnesium from a cobalt-nickel hydroxide raw material, and relates to the technical field of hydrometallurgy. The method comprises the following steps: slurrying a cobalt-nickel hydroxide raw material and deionized water, and washing the slurry to remove residual water-soluble calcium / magnesium at normal temperature in a carbon dioxide pressurized stirring manner, namely primary impurity removal; then, ferrous sulfate is used as an auxiliary rinsing agent for further washing and removing calcium / magnesium, and secondary impurity removal is achieved; the secondary impurity removal material is mixed and dissolved with sulfuric acid-ammonium phosphate, after the pH value is adjusted through ammonia water, most of residual calcium / magnesium ions are compounded to generate calcium phosphate / magnesium ammonium precipitate to be separated out, and at the moment, the filtered cobalt-nickel material is subjected to tertiary purification and impurity removal. The nickel-cobalt material subjected to three-time calcium / magnesium pre-removal can significantly reduce the impurity concentration of the acid-dissolved liquid, and lays a solid foundation for shortening the extraction stage number, reducing the extraction workload, reducing the extraction input cost and improving the product quality for a subsequent extraction production line.

The invention provides a preparation method of a copper-doped nickel hydroxide self-supporting electroreduction nitrate catalyst. The preparation method comprises the following steps: ultrasonically washing foamed nickel with ethanol, diluted hydrochloric acid and ultrapure water respectively; and then transferring the treated foamed nickel to a polytetrafluoroethylene lining containing a hydrogen peroxide aqueous solution and copper salt, assembling a reaction kettle, finally putting the reaction kettle into a drying oven for reaction, cooling to room temperature, taking out the self-supporting catalyst, cleaning with water, and drying to obtain the copper-doped nickel hydroxide material. The preparation method of the catalyst is an innovative construction method of an electro-catalysis nitrate reduction catalyst, a brand-new catalysis strategy is provided for normal-temperature and normal-pressure electro-catalysis water body nitrate reduction synthesis of ammonia, meanwhile, the preparation process route of the catalyst is simple and easy to implement, high electro-catalysis performance is achieved, and the method is suitable for industrial production. Certain potential application prospects are realized.

The present invention provides a method for improving the main components in a nickel-cobalt hydroxide intermediate product. The improvement method comprises: step S100, using an alkaline substance to perform a first activation on the nickel-cobalt hydroxide intermediate product slurry to obtain a first activated product slurry; step S200, adjusting the solid content of the first activated product slurry; step S300, using a reducing agent to perform a second activation on the first activated product slurry to obtain a second activated product slurry; step S400, adjusting the solid content of the second activated product slurry; step S500, adding the second activated product slurry to a nickel-cobalt solution for conversion reaction to obtain nickel-cobalt hydroxide and a converted liquid. The method of the present invention can significantly increase the total content of nickel and cobalt in nickel-cobalt hydroxide to a level of more than 50%. It solves the problem of high impurity content of magnesium, manganese and the like in the nickel-cobalt hydroxide intermediate product, high sulfate content, and the resulting increase in subsequent refining production costs.

The application provides a method for efficiently and selectively removing iron and chromium from cobalt-nickel hydroxide raw materials, which can realize the synchronous and deep removal of iron and chromium impurities for high-iron and high-cobalt nickel hydroxide raw materials through the synergistic process of acid leaching, reduction pH adjustment, oxidation precipitation and solid-liquid separation, and the concentrations of iron and chromium in the purified nickel-cobalt liquid are both controlled below 10 mg / L, and the impurity removal precision meets the subsequent high-purity production requirements; the chromium-goethite co-precipitation crystal product is generated in situ in the reaction, and has excellent settling and filtering performance, solving the problems of difficult colloid precipitation and filtration and easy equipment blockage in the traditional method, and the process route is short and the reaction conditions are mild, which can effectively reduce the adsorption entrainment and co-precipitation loss of nickel and cobalt valuable metals, and while realizing the efficient and deep purification of iron and chromium, the excellent solid-liquid separation performance and high main metal recovery rate are also considered, and the method is suitable for the industrial purification treatment of high-iron and high-chromium complex cobalt-nickel raw materials.