168results about "Ferric oxides" patented technology

Systems and methods for generating hydrogen through serpentinization of iron-bearing rock, including mafic rock, ultramafic rock and banded iron formations is presented herein. The systems and methods use geothermally-heated and / or surface-heated fluid circulating through one or more fluidically-communicative wellbores to accelerate the production of hydrogen. A geothermal-injector wellbore is formed in a geothermal rock layer, and is communicative with a separate geothermal-collection wellbore, also formed in the geothermal layer. Fluid is pumped through the geothermal-injector wellbore, geothermally heated, collected by the geothermal-collection wellbore, and injected into a targeted rock layer that includes iron-bearing rock. The heated fluid increases the rate of hydrogen production though serpentinization of the rock, which is then collected through a separate producer wellbore. In some cases, a serpentinization-injector wellbore is used to circulate surface-heated and / or chemically-treated fluid to the targeted rock layer to accelerate hydrogen production.

The present invention provides a method of producing hydrochloric acid, comprising reacting high-temperature gaseous chlorine and water vapour in a carbon-free reverse Deacon reaction (RDR) at a temperature of from about 450 to about 750 °Celsius to produce a mixture of gases comprising hydrogen chloride and oxygen. The chlorine is produced by fusing and electrolysing sodium or magnesium chloride in solid phase. The water vapour comes from thermally decomposing a hydroxide of at least one of calcium, magnesium and iron in the absence of oxygen to produce the water vapour without any admixture of oxygen (e.g., from atmospheric air). The mixture of gases produced by the RDR is immediately contacted with liquid water to dissolve the hydrogen chloride therein, thereby producing hydrochloric acid and a stream of tail gases. Heat is extracted from the hydrochloric acid to maintain its temperature substantially constant until the stream of tail gases is no longer in contact therewith. Thus the chlorine and water vapour are both supplied to the RDR at high purity and require little, if any, preheating. Heat extracted from contacting the mixture of gases with liquid water may be used to keep the RDR within its range of operating temperatures. Oxygen can be separated from the stream of tail gases, and the oxygen-depleted stream can be recycled back to the RDR to give a high percentage conversion of chlorine to hydrogen chloride. The RDR may be uncatalysed and kept within its operating temperature range by radio-frequency volumetric heating in at least one of the IEEE Ku-, K- and Ka-bands. The invention also provides a corresponding apparatus (1h) for producing hydrochloric acid, comprising an electrolytic cell (10) for the electrolysis, a gas-tight kiln (20) for the thermal decomposition, a gas-phase reactor (30) for the RDR, and an absorber (40) for dissolving the hydrogen chloride in the liquid water. The apparatus (1h) may further comprise a separator (80) for separating the stream of tail gases into the oxygen-depleted stream and a stream of oxygen, which may be fed to a steelmaking apparatus (90), for example. The liquid water for dissolving the hydrogen chloride can come from condensing water vapour obtained by drying an aqueous solution of sodium or magnesium chloride or of sodium hydroxide. The apparatus (1h) may therefore also comprise a dryer (60) for drying this aqueous solution, and a condenser (70) for condensing the water vapour thus obtained. Sodium chloride or magnesium chloride in solid phase derived from drying the aqueous solution may be recycled back to the electrolytic cell (10). Electricity for the electrolysis can come from a renewable resource. At least some of the heat for the thermal decomposition may come from the liquid metal which is a co-product of the electrolysis. The invention is therefore highly energy efficient and requires little, if any, extra energy, apart from the electricity required for the electrolysis. The invention also uses commonly available ingredients and produces no greenhouse gases.

The invention relates to the technical field of lithium ion batteries, and discloses a lithium supplement agent precursor and a preparation method thereof, a lithium supplement agent, a lithium ion battery and electric equipment. The chemical formula of the lithium supplementing agent precursor is Fe2-x-yAlxMeyO3 + / -delta, the value of x, the value of y and the value of delta enable the chemical formula to keep valence equilibrium, x is larger than or equal to 0 and smaller than or equal to 0.4, y is larger than or equal to 0 and smaller than or equal to 0.1, and Me is selected from at least one of Ni, Co, Cr, Mn, Ti and Zr. After the lithium supplement agent precursor is mixed with lithium and sintered into the lithium supplement agent, the morphology has inheritance, the mechanical strength is higher than that of an irregular morphology, the specific surface area of the lithium supplement agent can be reduced, the side reaction with an electrolyte is reduced, the cycle performance of a battery is improved, the compaction density of the material can be improved, and the service life of the battery is prolonged. And the material has a good application prospect in lithium ion batteries.

The invention discloses a preparation method and application of a Fe2O3 catalyst, and the preparation method of the Fe2O3 catalyst comprises the following steps: (1) dissolving a first ferric salt and a second ferric salt in water to form a solution, adding an organic solvent, adding alkali to adjust the pH value to 8-10, and placing at 150-170 DEG C for hydrothermal reaction; and (2) separating the solid in the step (1), and calcining the solid intermediate at 490-510 DEG C to obtain the Fe2O3 catalyst. According to the invention, two iron salts are adopted to form a precursor with a specific structure in a high-temperature and high-pressure water-organic solvent environment, and then the precursor is calcined at a specific temperature to obtain the Fe2O3 catalyst with high medium and low temperature activity and a wider active temperature window, and the Fe2O3 catalyst is suitable for flue gas denitration of glass furnaces, cement furnaces and the like.

The invention discloses a method for recycling and regenerating a positive electrode material of a waste lithium iron phosphate battery, and relates to the technical field of positive electrode materials of lithium iron phosphate batteries. When the lithium iron phosphate battery positive electrode material is prepared, recycled lithium carbonate, recycled iron oxide red, ammonium dihydrogen phosphate, lithium fluoride, cerium nitrate hexahydrate, lanthanum nitrate hexahydrate and glucose are mixed and calcined to prepare doped modified lithium iron phosphate; coating the surface of the doped modified lithium iron phosphate with polyaniline to prepare polyaniline-coated lithium iron phosphate; and mixing the polyaniline-coated lithium iron phosphate, a conductive agent and a binder, and coating an aluminum foil with the mixture to prepare the positive electrode material of the lithium iron phosphate battery. The lithium iron phosphate battery positive electrode material prepared by the invention has good cycle performance.

This invention belongs to the field of aerogel technology, and relates to a silicon-based aerogel composite material, its preparation method, and its application. The preparation method of the silicon-based aerogel composite material is as follows: An active component precursor is added to a solvent and stirred until homogeneous, forming an active component precursor solution; ethanol and acid are added to the silicon-based precursor, stirred until homogeneous, and cooled to room temperature to form a silicon-based precursor solution; the active component precursor solution is added to form a precursor-silica sol mixed solution; an alkaline solution is added and stirred until homogeneous, forming a mixed solution; a stepped hot melt-gel treatment is performed, followed by standing to form a silicon-based composite wet gel; solvent replacement and drying yield silicon; the stepped hot melt-gel reaction includes 2-5 temperature stages, each lasting 10-80 minutes at 50-100°C. This invention employs a controllable stepped hot melt-gel process to obtain a silicon-based aerogel composite material with both high specific surface area and excellent mechanical properties.

The invention relates to the technical field of hydrochloric acid pickling waste liquid recovery treatment, and particularly discloses a production method and device for recycling hydrochloric acid pickling waste water, and the production method comprises the steps of purification and impurity removal, filter pressing to remove tailings, neutralization reaction, iron red filtration, refining electrolysis to separate acid and alkali and the like. According to the production method, full-quantization high-value recovery of the hydrochloric acid pickling wastewater is achieved, remarkable economic, environmental and industrial application values are achieved, regenerated hydrochloric acid and liquid caustic soda can be directly recycled, closed-loop utilization of resources is achieved, meanwhile, a high-temperature roasting process is abandoned, energy consumption of each ton of waste liquid is reduced, purchased chemicals are reduced, and the production method is suitable for large-scale production of enterprises. The manganese ion removal rate is greater than or equal to 99% through graded impurity removal, and the product purity is high; and only a small amount of hazardous waste tailings are generated, secondary pollution is avoided, the triple targets of wastewater treatment, resource recovery and economic benefits are achieved, and technical support is provided for sustainable development of enterprises.

A method for preparing a two-dimensional porous oxide belongs to the technical field of porous oxide preparation. The method includes the following steps: (1) using a metal salt as a precursor, an ion-intercalated two-dimensional oxide is prepared by a molten salt method; (2) the ion-intercalated two-dimensional oxide is mixed with a lithium initiator, reacted for a predetermined time, and then the unreacted lithium initiator is removed, filtered, and washed to obtain the two-dimensional porous oxide. The two-dimensional porous oxide prepared by this method forms uniform pores with a pore size range of 2-10 nm and a specific surface area of ​​200-300 m². 2 / g.

A method for utilizing red mud and coal gangue, comprising: pretreating the red mud and the coal gangue, wherein the pretreatment comprises: at least grinding the red mud and the coal gangue, mixing the ground red mud and the coal gangue with gypsum to form a grinding mixture, and sieving the grinding mixture to obtain a first undersize product; reducing and roasting and activating the first undersize product to obtain a reduction roasting product; and chemically treating the reduction roasting product to obtain an iron red product. The method for utilizing red mud and coal gangue provided by the present application can realize efficient reuse of industrial solid waste red mud, coal gangue and desulfurization gypsum, achieve the effects of reducing environmental pollution and reasonably utilizing resources, and improve the efficiency of preparing iron red based on red mud and coal gangue and the purity of the iron red.

The invention provides a method for preparing iron red by chloridizing and separating an iron-containing alloy and application, and the method comprises the following steps: adding a chlorinating agent into the iron-containing alloy for roasting to obtain roasting slag and roasting flue gas; introducing a first oxidizing gas into the roasting flue gas, and performing primary roasting transformation to obtain a solid and a first mixed gas; introducing a second oxidizing gas into the solid, and carrying out secondary roasting transformation to obtain the iron oxide red and a second mixed gas; wherein the first mixed gas comprises chlorine and ferric oxide gas; the second mixed gas comprises oxygen and chlorine. The method has the characteristic of short flow, realizes zero emission through chlorine medium closed-loop circulation, has the advantages of environmental friendliness and process advancement, and is suitable for large-scale industrial production.

The application discloses a high-concentration sulfate radical acid mine water treatment method based on acid-resistant SRB biological cathode, which comprises the following steps: after the acid mine water is filtered through a grid, the acid mine water is fed into an adjusting tank; the wastewater in the adjusting tank is fed into a biological membrane electrochemical device to perform an electrochemical reaction; in an anode chamber, Fe 2+ in the wastewater is oxidized into Fe 3+ and releases electrons; in a cathode chamber, the acid-resistant SRB bacterial membrane loaded on the surface of a carbon felt electrode utilizes the transmitted electrons to reduce SO4 2‑ into S 2‑ ; CO2 micro-bubbles are fed into the liquid in the cathode chamber to react with S 2‑ to generate sulfur precipitate, and the mixed solution after the reaction is fed into a cyclone separator to realize gas-solid separation; Fe 3+ in the water in the anode chamber generates Fe(OH)3 precipitate through a hydrolysis reaction, the Fe(OH)3 precipitate is mixed with sodium silicate, and is calcined to be converted into alpha-Fe2O3 with magnetism. The method can effectively remove SO4 2‑ and recover iron mud.

The invention discloses a method for preparing vinyl chloride by electrocatalytic dechlorination of 1, 2-dichloroethane, a working electrode of the method takes a metal oxide as a catalyst, and the metal oxide is selected from at least one of the following metal oxides: Pd, Mn, Fe, Co, Ni, Cu, Ru and Mo. According to the invention, the metal oxide powder is used as the electrocatalyst, the catalyst is coated on the electrode material to prepare the working electrode, the working electrode is applied to electrocatalytic dechlorination reaction of 1, 2-dichloroethane, vinyl chloride can be generated at high selectivity at room temperature, a new way is opened up for production of vinyl chloride by electrocatalytic dechlorination, and the method has wide application prospect. And a green and low-cost solution is provided for efficient synthesis of vinyl chloride.

This invention belongs to the field of solid waste resource recycling technology in the metallurgical industry. It discloses a process for preparing iron oxide red and extracting titanium dioxide from high-iron red mud. The process involves mixing high-iron red mud with an alkaline agent, followed by water leaching to obtain a water-leached solution and a water-leached residue. The water-leached solution undergoes desilication and carbon removal treatment to obtain aluminum hydroxide and sodium carbonate solutions. The water-leached residue is then acid-leached with sulfuric acid; silicon is recovered as silica gel, while aluminum and iron enter the solution and undergo polymerization to prepare a water purification agent. The acid-leached residue is treated with a high-temperature heap leaching-water leaching process using concentrated sulfuric acid to achieve efficient dissolution and separation of titanium. The titanium-iron mixed solution is subjected to stepwise crystallization control, successively precipitating ferric sulfate and ferrous sulfate crystals, which are then pyrolyzed to generate high-purity iron oxide red. Finally, the mother liquor is subjected to titanium precipitation and pyrolysis to obtain titanium dioxide. This invention achieves efficient separation and high-value utilization of all components of iron, titanium, aluminum, and silicon in red mud. The process flow is rationally cyclical, resulting in high-value-added products with low energy consumption and no secondary pollution.

The present invention provides a powder that has high reaction efficiency and can maintain that reaction efficiency even after repeated oxidation-reduction reactions. The powder comprises iron oxide particles and oxide particles, wherein the oxide particles contain at least one of Cr and Si as an oxide, the average particle diameter of the oxide particles is 0.5 nm or more and 100 nm or less, the average value of the ratio Fmax / Fmin (the ratio of the maximum Ferret diameter Fmax to the minimum Ferret diameter Fmin) of the oxide particles is 2.0 or more, and the oxide particles are in contact with the iron oxide particles at an average contact rate of 20% or more and 80% or less.

The invention discloses a staged hydrothermal synthesis method of high-dispersion small-size nano iron oxide, which comprises the following preparation steps: (1) sequentially adding a surfactant, an iron source and a reaction aid into a water-organic solvent binary mixed solvent, and uniformly stirring to obtain a mixed solution; (2) carrying out a nucleation reaction on the mixed solution obtained in the step (1) in a closed container at 80-100 DEG C for 0.5-1.5 h, and then growing at 120-180 DEG C for 5-12 h to obtain a precursor solution; and (3) centrifuging, washing and drying the precursor solution obtained in the step (3), and calcining at 450-550 DEG C for 1-3 hours to obtain the high-dispersion small-size nano iron oxide. According to the invention, a staged hydrothermal reaction mechanism is innovatively introduced, and the reaction auxiliary agent and the surfactant are combined, so that the nano-particles with small size, high dispersion and low-temperature high crystallization are obtained.

The application discloses a hydrochloric acid pickling waste liquid resource treatment process based on supergravity neutralization and ammonia closed loop, relates to the technical field of hydrochloric acid pickling waste liquid recovery treatment, and comprises the steps of purification and impurity removal, supergravity neutralization, solid-liquid separation, ammonia recovery and product preparation, etc. The supergravity reaction device is used to realize high-speed and high-efficiency neutralization of the waste liquid and ammonia gas, and through the reaction of calcium oxide and the neutralization product, i.e. ammonium chloride, ammonia gas is recovered under negative pressure and is used in the neutralization step again, forming an ammonia closed loop cycle. Meanwhile, the valuable components in the waste liquid are converted into high-purity iron red products and calcium chloride products in the whole process, and high-quality purified water is recovered. The application solves the problems of high energy consumption, low efficiency, insufficient resource recovery and secondary pollution caused by the traditional hydrochloric acid pickling waste liquid treatment method, realizes clean and efficient disposal of the waste liquid and full-amount high-value recovery of resources, and has both economic benefits and environmental benefits.

The invention discloses a method for realizing degradation of polyalkylene oxide compounds and controllable molecular weight through a promoter, which comprises the following steps: adding a photodegradation promoter into a high-molecular-weight polyalkylene oxide product, adjusting the proportion of the promoter and the proportion of effective components, and accurately controlling the shear molecular weight under the irradiation of an ozone emitter, so that the molecular weight of the polyalkylene oxide compounds is controllable. According to the invention, polyalkylene oxide with different molecular weights of 30,000-3,000,000 is prepared by using the photodegradation cocatalyst, so that the photodegradation cocatalyst can meet the requirements of customers in different fields, and meanwhile, the photodegradation cocatalyst prepared by the invention can be recycled to achieve the benefits of reducing cost and improving efficiency.

This invention relates to an atomic-level manufacturing method and apparatus for two-dimensional metal oxide nanosheets based on controllable micro-explosion, belonging to the field of functional nanomaterials and atomic-level precision manufacturing technology. This invention uses transition metal energetic complexes and energetic oxygen compounds as metal-oxygen integrated precursors. Under the constraint of an array-type nano-confined microcavity, controllable micro-explosions are synchronously triggered by nanosecond lasers to achieve nanosecond-level stoichiometric precision in the directional self-assembly of two-dimensional metal oxide nanosheets. The preparation cycle of this invention is reduced to less than 10 minutes, and the overall energy consumption is less than 1% of that of the traditional hydrothermal method. The product has excellent specific surface area, photocatalytic and cycling performance, and is 100% compatible with existing mass production lines. It is suitable for large-scale manufacturing in fields such as photocatalysis, energy storage, gas sensors, and environmental governance.

Nanoparticulate material suitable for administration to a subject, the nanoparticulate material having bound to its surface: (a) copolymeric steric stabiliser that promotes dispersion of the nanoparticulate material in a liquid, wherein the copolymeric steric stabiliser comprises (i) an anchoring polymer segment having one or more binding groups that bind the copolymeric steric stabiliser to the nanoparticulate material, and (ii) a steric stabilising polymer segment that is different from the anchoring polymer segment, and (b) copolymeric mapping moiety comprising (i) an anchoring polymer segment having one or more binding groups that bind the copolymeric mapping moiety to the nanoparticulate material, (ii) one or more mapping groups comprising an agent that specifically binds to fibroblast activation protein (FAP), and (iii) a coupling polymer segment that is different to the anchoring polymer segment, wherein the coupling polymer segment couples the anchoring polymer segment to the one or more mapping groups.

A system for producing iron oxide yellow from coal gangue leachate comprises a first reaction tank, a second reaction tank, a mixing tank and a filter press, a first inlet and a second inlet are formed in the top of the first reaction tank, a first pipeline is arranged at the bottom of the first reaction tank to supply materials to the second reaction tank, a second pipeline is arranged to supply materials to the mixing tank, and a third inlet and a fourth inlet are formed in the top of the second reaction tank. A first aeration pipe is arranged in the second reaction tank, an overflow pipe is arranged on the side wall of the second reaction tank, a fifth valve is arranged to control opening and closing, a third pipeline is arranged at the bottom of the second reaction tank to supply materials to the mixing tank, a fifth inlet is formed in the top of the mixing tank, a second aeration pipe is arranged in the mixing tank, and a fourth pipeline is arranged at the bottom of the mixing tank to supply materials to the filter press; a fourth valve is arranged on the fourth pipeline, and a solid-phase discharge port of the filter press is used for discharging iron oxide yellow outwards. The device is simple in structure and low in production cost, and can effectively avoid environmental pollution on the basis of improving the utilization value of the coal gangue leachate.

The invention discloses a method for recovering valuable elements in liquid obtained after bauxite wet desulphurization, and relates to the technical field of bauxite resource utilization. Comprising the following steps: carrying out ceramic membrane filtration pretreatment on the bauxite wet desulfurization liquid to remove impurities; the silicon element is recycled in a targeted manner through a compound flocculation-calcination process to obtain the white carbon black; the iron element is recycled through ozone oxidation-ammonium bicarbonate precipitation, and high-purity iron oxide is prepared; separating and purifying an aluminum element through a seed crystal induction-calcination process to obtain metallurgical-grade aluminum oxide; a fluorine-containing precipitant is used for selectively precipitating and recovering magnesium element to obtain a high-quality magnesium salt product; and neutralizing the tail liquid, and discharging after reaching the standard. According to the method, accurate separation and high-valued utilization of four elements of aluminum, iron, silicon and magnesium are realized through a synergistic process of targeted recovery of silicon, gradient separation of iron and aluminum and selective precipitation of magnesium, and the problems of silicon resource waste, low element separation efficiency, insufficient product purity, secondary pollution and the like in a traditional process are thoroughly solved; all-component resource comprehensive utilization of desulfurized liquid resources is achieved.

The application discloses a neodymium-iron-boron secondary waste recycling method, which comprises the following steps: step 1, reacting neodymium-iron-boron secondary waste with acid solution, controlling the pH of the solution after reaction to be 0.5-1.5, and performing solid-liquid separation to obtain filter liquor A containing Fe 3+ and filter residue A; step 2, reducing Fe 3+ in the filter liquor A into Fe 2+ , performing solid-liquid separation to obtain filter liquor B and filter residue B; step 3, adjusting the pH of the filter liquor B to 2-6, performing solid-liquid separation to obtain filter liquor C and filter residue C; and step 4, reacting the filter liquor C with a precipitant, performing solid-liquid separation to obtain filter residue D and filter liquor D. The present application realizes short-process comprehensive utilization of oxalic acid, hydrochloric acid and iron resources, is friendly to the operation environment, does not need strong-acid and strong-alkali equipment, and can simultaneously realize green and efficient comprehensive utilization of iron-containing waste residue and oxalic acid wastewater.

This invention discloses an acetone sensor based on MOF-derived oxygen-vacancy-rich α-Fe₂O₃ and its fabrication method. The aforementioned acetone gas sensor has a planar structure, including an Al₂O₃ ceramic sheet, a pair of interdigitated gold electrodes printed on the upper surface of the Al₂O₃ ceramic sheet, a RuO₂ heating film printed on the lower surface of the Al₂O₃ ceramic sheet, a pair of strip-shaped gold electrodes printed on the surface of the RuO₂ heating film, a gas-sensitive film coated and fixed to the surface of the interdigitated gold electrodes, platinum wire leads I, II, III, and IV. The gas-sensitive film uses an oxygen-vacancy-rich α-Fe₂O₃ sensitive material. This invention can produce an acetone sensor with excellent acetone sensitivity characteristics, enabling efficient detection of low concentrations of acetone. It overcomes the problems of insufficient sensitivity and slow response speed of traditional gas sensors in acetone detection. Furthermore, the acetone sensor fabrication process is highly compatible with existing microfabrication technologies, meeting the needs of industrial production.

Provided are: a ferrite powder whereby, when the ferrite powder is applied in a composite material, dropping out of ferrite particles is suppressed without moldability and filling ability being compromised; a ferrite resin composite material; and an electromagnetic shielding material, an electronic material, or an electronic component. This ferrite powder includes at least spherical or polyhedral ferrite particles in which a step structure is provided on surfaces thereof, the step structure having a polyhedral outline in the surfaces of the ferrite particles.

Provided is a method for producing a reduced form of a metal oxide, the method being capable of preventing the production of carbon dioxide. The method for producing a reduced form of a metal oxide may use a partition member and a high-melting-point material that comprises an absorbent material and an insulation material.

The invention provides an iron oxide powder production method based on strip steel pickling, which comprises the following steps: pre-cleaning, pickling and rinsing strip steel in sequence, collecting waste acid obtained after pickling, and collecting rinsing water obtained after rinsing, a water source for pre-cleaning comprising a first part of rinsing water; carrying out impurity removal treatment on the waste acid to obtain treated acid; heating and concentrating the treated acid to obtain feed liquid; spraying the feed liquid into a furnace chamber of a roasting furnace for roasting, collecting iron oxide powder at a discharge port in the bottom of the furnace chamber, and collecting first furnace gas discharged from an exhaust port in the top of the furnace chamber; the first furnace gas provides heat for the treatment acid subjected to heating concentration treatment, and then second furnace gas is collected; contacting the second furnace gas with a second part of rinsing water to obtain third furnace gas and regenerated acid; a water source for pickling comprises regenerated acid. The method can reduce the content of sodium, potassium and calcium in the waste acid, and can reduce the chlorine content in the iron oxide powder.

The application discloses a kind of nickel-iron layered double hydroxide / iron oxide composite material and preparation method thereof, main preparation steps are respectively configured ferric salt and triethanolamine solution;The complex solution of ferric ion and triethanolamine is obtained after triethanolamine solution is added dropwise into ferric salt solution, and then the solution is treated using microwave hydrothermal to obtain iron oxide precursor dispersion;After the mixed solution of nickel salt and triethanolamine is configured, it is added into iron oxide precursor dispersion and is mixed uniformly by ultrasonic treatment;The mixture is transferred to microwave hydrothermal reaction bottle, and then microwave hydrothermal treatment is carried out, after treatment is completed, precipitated product is washed by centrifugation using deionized water and ethanol, and finally vacuum drying obtains nickel-iron layered double hydroxide / iron oxide composite material.The nickel-iron layered double hydroxide / iron oxide composite material prepared by the microwave hydrothermal method of the application has simple preparation process and shows good electrochemical oxygen evolution activity.

The present disclosure relates to a process of extracting magnesium or magnesium compounds from a ferronickel slag feed comprising magnesium and silica compounds, the process comprising: a comminution step to reduce a particle size distribution of the ferronickel slag feed; and an acid leaching step after the comminution step, comprising: leaching the ferronickel slag feed from the comminution step in a vessel with hydrochloric acid at a concentration of 5-15 wt.% HCl to form a leached slurry, controlling the hydrochloric acid concentration during leaching by adding further hydrochloric acid to the vessel to maintain the hydrochloric acid concentration at 5-15 wt.% HCl, and obtaining a leached slurry from the vessel, wherein the leached slurry comprises a liquid portion and a solids residue, and wherein the liquid portion comprises magnesium chloride.

This invention discloses a method for preparing iron oxide red using electroplating waste acid, belonging to the field of electroplating waste treatment technology, including the following steps: Step 1: Add an oxidant to the electroplating waste acid to remove Fe from the waste acid. 2+ Oxidized to Fe 3+ The pH is adjusted to 2-4 to obtain pretreated electroplating waste acid solution; Step 2: The pretreated electroplating waste acid solution is passed through an adsorption column equipped with solid phase extraction resin, and the first effluent is obtained after the column is completed; Hydrochloric acid solution is eluted through the adsorption column to obtain the second effluent; Step 3: The second effluent is used to prepare ferric hydroxide colloid by neutralization precipitation, and then the ferric hydroxide colloid is calcined to obtain iron oxide red. The iron oxide red product prepared by this method using electroplating waste acid solution as raw material through selective separation-purification-conversion process has good key indicators such as iron content, color difference, and oil absorption, realizing the high-value conversion from hazardous waste to industrial pigment.

The invention belongs to the technical field of preparation of iron oxide powder, and particularly relates to a production method of high-efficiency and environment-friendly high-purity iron oxide powder, which comprises the following steps: preparing soluble iron salt into an aqueous solution, adding a dispersing agent into the aqueous solution, and uniformly stirring; carrying out atomization treatment on the obtained solution through a pressure type atomizer or an airflow type atomizer; the atomized liquid drops enter a high-temperature reaction furnace, and air or oxygen is introduced into the high-temperature reaction furnace at the same time until atomization is finished; a product obtained after reaction enters a cyclone separator along with airflow for preliminary separation, and then fine collection is performed through a bag-type dust collector; and washing the collected ferric oxide crude product with deionized water for multiple times to remove impurity ions left on the surface, and drying. The method has the advantages of compact process flow, high reaction speed and controllable product performance. And the reaction contact area is increased through the atomization process, so that the oxidation reaction is rapidly carried out, the problem of non-uniform particle size distribution or easy agglomeration of the product in the traditional method is avoided, and the production efficiency is improved.