452 results about "Iron sulfate" patented technology

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a sodium ferric sulfate composite positive electrode material and a preparation method and application thereof. The preparation method of the sodium ferric sulfate composite positive electrode material provided by the invention comprises the following steps: (1) preparing a carbon-coated sodium ferric sulfate positive electrode material, mixing the sodium ferric sulfate positive electrode material with a citric acid solution, and performing ultrasonic treatment to obtain a modified sodium ferric sulfate positive electrode material; (2) stirring and mixing the modified sodium ferric sulfate positive electrode material and a composite conductive agent, shearing and dispersing, and carrying out ultrasonic oscillation, wherein the rotating speed of stirring and mixing is less than or equal to 2000rpm; the rotating speed of the shearing dispersion is greater than or equal to 5000rpm. The sodium ferric sulfate composite positive electrode material provided by the invention has relatively low shear viscosity and relatively high thixotropic index under the condition that the solid content is greater than or equal to 65%.

The invention relates to the technical field of sodium-ion batteries, in particular to a sodium-ion battery positive electrode material and a preparation method thereof.The sodium-ion battery positive electrode material comprises a sodium ferric sulfate precursor and a carbon coating layer coating the surface of the sodium ferric sulfate precursor; the sodium ferric sulfate precursor comprises a sodium source, an iron source, an antioxidant and halogenated carboxylic acid; and the carbon coating layer is formed by coating and sintering phosphate. Aiming at the problem that a carbon-coated positive electrode material in the prior art is easy to form defect points, the carbonization temperature in the sintering process is reduced by adding halogenated carboxylic acid into a precursor, so that the carbonization effect is improved, the probability of forming the defect points is reduced, and halogen ions are introduced into a carbon-coated layer in the sintering process to improve the conductivity; meanwhile, surface coating is carried out through phosphate, so that reaction of the positive electrode and electrolyte under a high-voltage condition can be effectively inhibited, gradual deterioration of the material structure due to moisture absorption in the circulation process is avoided, and the circulation stability of the material is improved.

The invention belongs to the technical field of sodium-ion battery materials, and mainly relates to a low-cost high-specific-energy mixed positive electrode material and a preparation method and application thereof. The mixed positive electrode material is prepared from 90 to 100 parts of P2 type layered oxide and 1 to 10 parts of polyanionic sodium ferric sulfate; the chemical formula of the P2 type layered oxide is Na2 / 3Ni2 / 3-xMn2 / 3-yTiMgZnO2, x is more than or equal to 0, and y is less than or equal to 1 / 3; the chemical formula of the polyanionic sodium ferric sulfate is Na < 2 + 2 > z Fe < 2-z > (SO4) 2, wherein z is more than or equal to 0 and less than or equal to 0.3. According to the mixed positive electrode material, through the synergistic effect of the crystal structures, the two materials are embedded or wrapped, so that the porosity is reduced, the compaction density is increased, and the specific discharge capacity is improved.

The invention discloses a biomass-inorganic-organic ternary composite flocculant and a preparation method and application thereof, and belongs to the field of coking wastewater treatment.The preparation method comprises the steps that chitosan serves as a substrate material, glutaraldehyde serves as a cross-linking agent, and polyferric sulfate (PFS) and chitosan are subjected to chemical cross-linking to generate an intermediate product PFS and chitosan composite particles; then potassium persulfate is used as an initiator, graft copolymerization of acrylamide and methacryloyloxyethyl trimethyl ammonium chloride is initiated through hydroxyl on the surface of PFS-chitosan, a cationic branched chain is introduced, and a final product is obtained. Through multi-component cooperation and structural design, the defects that a traditional flocculating agent is not thorough in demulsification, large in sludge amount, unstable in floc combination and the like in coking wastewater treatment are overcome, and the flocculating agent is particularly suitable for treating oil pollutants in coking wastewater.

The invention discloses a positive electrode material formed by compounding polyanionic sodium ferric sulfate and a layered transition metal oxide, and a preparation method and application thereof, and the preparation method comprises the following steps: preparing a sodium ferric sulfate positive electrode material, preparing a layered transition metal oxide positive electrode material, and mechanically mixing the sodium ferric sulfate and the layered transition metal oxide material, the composite material is obtained. The production process of the two materials is easy for large-scale production, has high similarity with the existing battery industrial equipment, is simple in method for compounding the two materials, and has large-scale industrial application value. The composite material has the stability of a polyanionic material and the high energy density of a layered oxide material, and has more excellent comprehensive electrochemical performance.

The invention discloses an oxide-coated ion-doped sodium ferric sulfate positive electrode material as well as a preparation method and application thereof. The positive electrode material is formed by compounding a sodium ferric sulfate bulk phase material doped with various valence metal cations and anions and coated with carbon similar to a positive temperature coefficient thermosensitive metal oxide. Wherein the metal cations with various valence states are doped on Na or Na / Fe ion sites of the sodium ferric sulfate, the doped anions occupy part of three-dimensional S-O tetrahedron positions, the inorganic carbon in the carbon compound is uniformly distributed in the sodium ferric sulfate bulk phase material, and the organic carbon is uniformly distributed outside the sodium ferric sulfate bulk phase material. The positive electrode plate assembled battery prepared from the positive electrode material has the advantages of high reversible charge-discharge capacity, excellent cycle performance and rate capability and high electron and ion migration rate in a low-temperature environment. The method is low in raw material cost, simple in synthesis method, short in production period and suitable for large-scale continuous production.

The present application relates to the technical field of sodium‑ion batteries, and provides a sodium iron sulfate-based composite positive electrode material, and a preparation method therefor and a use thereof. The sodium iron sulfate-based composite positive electrode material has a porosity of 0.1%-10% and a compacted density of 2.1-3 g / cm3; in addition, the sodium iron sulfate-based composite positive electrode material has a specific surface area of 5-12 m2 / g, and a sodium-rich impurity phase in the sodium iron sulfate-based composite positive electrode material has a mass percentage content of 0.1%-1%. The present application helps to improve the performance of batteries, such as the charge / discharge capacity and the initial coulombic efficiency.

The invention belongs to the technical field of electrochemistry, and particularly provides a lanthanum-cerium double-doped sodium ferric sulfate positive electrode material and a preparation method thereof. The material is composed of a matrix and a carbon coating layer coating the matrix, the matrix has a chemical expression of Na6Fe4-x-yLaxCey (SO4) 7, x is greater than or equal to 0.01 and less than or equal to 0.1, and y is greater than or equal to 0.01 and less than or equal to 0.1. The material is prepared through spray drying and high-temperature sintering treatment in sequence, the particle morphology is regular, and the particle size distribution is uniform; the electronic conductivity and Na < + > diffusion rate of the material are remarkably improved by rare earth doping, so that the material has more excellent low-temperature cycle performance, sodium storage performance and the like.

The invention discloses a carbon-coated sodium ferric sulfate positive electrode material, a preparation method thereof and a battery, and the preparation method comprises the following steps: dissolving anhydrous sodium sulfate and ferrous sulfate heptahydrate in a solvent according to a preset proportion, and adding a preset amount of inorganic carbon dispersion liquid to form a uniform suspension; carrying out spray drying on the turbid liquid to obtain a primary coating precursor; dispersing a conductive carbon black material in the solution to obtain a carbon dispersion liquid; putting the primary coated precursor into an aerial fog coating machine, pumping a carbon dispersion liquid into a nozzle, and coating through two-phase flow injection and collision with primary coated precursor powder to obtain a secondary coated precursor; and sequentially calcining, grinding and screening the precursor to obtain the carbon-coated sodium ferric sulfate positive electrode material. The preparation method disclosed by the invention adopts two common industrial treatment modes of spray drying and fluidization coating for preparation, and has the characteristic of easiness in amplification. The fluidization coating can effectively improve the coating uniformity of the solid-phase inorganic carbon on the particle surface.

The invention discloses a preparation process of berberine hydrochloride, and belongs to the technical field of berberine production. The invention relates to a berberine hydrochloride preparation process, which comprises: S1, mixing a ferric sulfate-aluminum sulfate composite salt, sodium chloride, zinc chloride and anhydrous formic acid, pre-activating, adding N-2, 3-dimethoxybenzyl homopiperony lamine hydrochloride, dropwise adding a glyoxal mixed solution, and carrying out a reflux reaction. And S2, cooling the reaction liquid until a solid is separated out, filtering, adding a filter cake and diatomite into purified water, stirring, adjusting alkali, heating, and continuously stirring for 0.5-1 hour. Cooling and filtering, and reserving filtrate; s3, adjusting the acidity of the filtrate, cooling and growing crystals; and filtering, rinsing a filter cake, and carrying out vacuum drying on the filter cake to obtain berberine hydrochloride. The berberine hydrochloride prepared by the method is high in yield and purity, and the preparation process is safe, short in flow and friendly to human bodies and environment.

The invention belongs to the technical field of positive electrode materials, and particularly relates to an anion-doped sodium ferric sulfate positive electrode material for a sodium ion battery as well as a preparation method and application of the anion-doped sodium ferric sulfate positive electrode material. The invention provides an anion-doped sodium ferric sulfate positive electrode material for a sodium ion battery as an electrode modification material, and the anion-doped sodium ferric sulfate positive electrode material comprises an anion-doped sodium ferric sulfate material with a general formula of Na < 6-2a > Fe (SO4) < 3-b > (BOx) , and is used for preparing a sodium ion battery positive electrode. The material is simple in preparation process, mild in reaction condition, low in cost and relatively high in reaction efficiency, the problems of relatively poor sodium storage capacity, cycle performance and water resistance of a sodium ferric sulfate material under high magnification in the prior art are solved, and the intrinsic conductivity of the sodium ferric sulfate material is remarkably improved; and the sodium-ion battery composite positive electrode material prepared from the composite positive electrode material has excellent rate capability and cycling stability.

The invention discloses an advanced treatment method of tungsten beneficiation wastewater, which is characterized in that a composite flocculant is adopted to flocculate the tungsten beneficiation wastewater, and the composite flocculant is mainly composed of cationic polyacrylamide, a flocculant A and lignocellulose, the flocculant A comprises at least one of polyferric sulfate, polyaluminum chloride, polyaluminum ferric chloride, polyaluminum ferric sulfate, ferric sulfate, ferrous sulfate and aluminum chloride. According to the advanced treatment method for the tungsten beneficiation wastewater, under the action of the composite flocculant, the cost of a treatment agent can be reduced to about 0.16-0.20 yuan / m < 3 >, the cost reduction amplitude is as high as 80% or above, the treatment time can be shortened to be within 10 min, the precipitation time is greatly shortened, meanwhile, suspended solids in the wastewater can be effectively removed, actual production requirements are met, and the method is suitable for industrial production. The method has the advantages of low treatment cost, high treatment efficiency, good removal effect, good adaptability and the like, can realize advanced treatment of the tungsten beneficiation wastewater, and is high in use value and good in application prospect.

The invention relates to the technical field of sodium ion battery positive electrode materials, in particular to a composite sodium ferric sulfate positive electrode material, a sodium ion battery and a preparation method. The preparation method comprises the following steps: preparing a group IIIA metal doped composite sodium ferric sulfate precursor; mixing with a solution containing a sodium source, an iron source and a phosphorus source; and performing staged heat treatment under a protective atmosphere to form a pyrophosphate ferric phosphate sodium coating layer. The particle size D50 of the composite sodium ferric sulfate positive electrode material is 3-5 [mu] m, and the composite sodium ferric sulfate positive electrode material can inhibit iron dissolution and enhance structural stability through bulk phase doping and surface coating cooperation, can prolong the cycle life of a battery and reduce gas production, and is suitable for a high-performance sodium ion battery.

The invention relates to a process for preparing pure iron by using red mud, which is characterized in that the red mud is Bayer process red mud, i.e., solid waste residue formed by solid-liquid separation after aluminum oxide is dissolved out from bauxite through high temperature, high pressure and strong alkali in the process of producing aluminum oxide by adopting a Bayer process, so that the environmental burden caused by the Bayer process red mud can be solved; the method is beneficial for reducing carbon emission in the aspect of iron element extraction and promoting development of a green metallurgical technology, and is characterized by comprising the following steps: taking Bayer process red mud as a raw material, carrying out acid leaching on the Bayer process red mud to obtain a ferrous oxalate extract, calcining the ferrous oxalate to obtain iron oxide, and recycling the iron oxide. And dissolving the ferric oxide into a sulfuric acid solution to obtain a ferric sulfate solution, taking the ferric sulfate solution as an electrolyte in an electrolysis device, and obtaining electrolytic iron through the electrolysis device, so that the pure iron is prepared from the red mud.

The invention relates to the technical field of low-carbon building materials, and particularly discloses a high-strength super-retarding super-sulfate cement material as well as a preparation method and application thereof. The cement material comprises the following raw materials in parts by weight: 75-85 parts of a slag gelling component, 10-20 parts of gypsum, 0.5-5 parts of an alkali activator, 1-5 parts of a composite retarder, 0.35-1 part of a water reducing agent and 0.2-1 part of a defoaming agent. Wherein the composite retarder is prepared from the following components in parts by weight: 2-3 parts of fluosilicate, 8-10 parts of sulphoaluminate cement and ferric sulfate, and the content of the ferric sulfate is 1.2-1.5 times that of the fluosilicate. The composite retarder disclosed by the invention not only has better stability, but also can effectively prolong the setting time of the super-sulfate cement material in a high-temperature environment, and greatly improves the mechanical strength of the super-sulfate cement material in the whole age.

The invention relates to the technical field of knowledge maps, in particular to a ferric sulfate knowledge map construction method based on multi-modal heterogeneous data, which comprises the following steps: acquiring multi-modal heterogeneous data in a ferric sulfate production process; taking a mechanical operation rhythm obtained by analyzing the multi-axis high-frequency vibration signal data as a main time reference to form a public time reference; performing alignment and association on the tomography data and the acoustic emission data based on public time reference to obtain an instantiation process normal form entity in the knowledge graph; analyzing the time sequence of the process normal form entity according to a predefined ontology relationship type, establishing a directed relationship with a state transition probability attribute, and forming a probability state machine data structure traversed by a graph query language in a knowledge graph; filling structured attributes are defined for process normal form entities in the knowledge graph. According to the method, the construction of the ferric sulfate knowledge graph is realized by fusing multi-modal data and state analysis.

The invention provides a composite sodium ferric sulfate positive electrode material and a preparation method thereof, a sodium ion battery positive plate and a sodium ion battery, and relates to the technical field of batteries. According to the preparation method of the composite sodium ferric sulfate positive electrode material, boron is doped in the preparation process of the conductive agent, so that the conductivity of the conductive agent can be improved, and the dosage of the conductive agent is reduced; the conductive agent is added in the preparation process of the positive electrode material, so that the dispersion uniformity of the conductive agent can be improved; through high-temperature sintering, the contact between the conductive agent and the active material is firmer, and the dry-method pole piece prepared from the material has lower pole piece resistance.

The invention provides a preparation method of a sodium ferric sulfate positive electrode material, which comprises the following steps: mixing a sodium source, an organic carbon source and an iron source solution, and carrying out spray drying after dissolving to obtain a precursor material; carrying out acid ball milling on the precursor material and an inorganic carbon source, and then drying to obtain a pre-firing material; sintering the pre-sintering material under the protection of inert atmosphere to obtain a sintered material; and grinding and sieving the sintered material to obtain the sodium ferric sulfate positive electrode material. According to the invention, a spraying and ball milling combined process is adopted, further homogenization of materials is promoted by adjusting the pH value of a ball milling system and adding a grinding aid, and a favorable environment is provided for carbon coating under low-temperature sintering.

The invention discloses a multi-band high-stability ferrite magnetic material composite formula and a preparation process, and relates to the technical field of magnetic materials. The ferrite magnetic material composite formula comprises 38-42 parts of ferric oxide powder, 37-41 parts of ferroferric oxide powder, 6-12 parts of graphene nanosheets, 5-7 parts of hydroxypropyl methyl cellulose, 6-9 parts of lanthanum oxide, 4-6 parts of scandium oxide, 1-3 parts of nano titanium dioxide, 4-6 parts of bismuth magnesium boron, 9-13 parts of ferric sulfate, 3-5 parts of manganese sulfate, 4-6 parts of zinc sulfate, 2-4 parts of copper sulfate and 2-3 parts of samarium sulfate. By utilizing a physical vapor deposition gradient doping process, the problems that an existing ferrite magnetic material is single in electromagnetic performance, cannot stably and efficiently work in a multi-frequency-band complex electromagnetic environment and cannot meet the requirements of the fields of communication, radar, electronic countermeasure and the like for wide-frequency-band and high-performance magnetic materials can be solved.

The invention discloses a system and method for treating metallurgical dust and sludge and ferric sulfate slag through a rotary kiln, and the system comprises the rotary kiln which is used for carrying out pelletizing forming, pre-reduction desulfurization and deep reduction on the metallurgical dust and sludge and sulfuric acid slag of an iron and steel plant; the rotary kiln is sequentially provided with a pelletizing section, a pre-reduction desulfurization section, a deep reduction section and a discharging section from the kiln tail to the kiln head, and an inclined check ring is arranged in the pelletizing section; the kiln head of the rotary kiln is provided with an air nozzle, and the kiln tail is provided with a smoke outlet. The surface cooler is used for cooling the rotary kiln flue gas from the rotary kiln to obtain low-temperature flue gas; the zinc sulfate preparation module is used for treating the low-temperature flue gas and preparing a zinc sulfate product. According to the method, resource utilization and high-value utilization of the metallurgical dust sludge and the sulfuric-acid slag of the iron and steel plant can be achieved, low-sulfur and high-iron metallized pellets and zinc sulfate products are produced, and comprehensive utilization of iron, zinc and sulfur in the metallurgical dust sludge and the sulfuric-acid slag is achieved.

The invention discloses a method for preparing lithium iron manganese phosphate by obtaining a high-performance precursor from waste lithium iron phosphate. According to the method disclosed by the invention, the chelating effect of phytic acid and ferric ions is utilized, so that an organic carbon source is introduced into hydrated iron phosphate precipitated from the waste lithium iron phosphate leaching solution, the fusion growth of iron phosphate particles is effectively prevented in the subsequent high-temperature roasting process, and the high-performance lithium manganese iron phosphate precursor is obtained from the waste lithium iron phosphate. The method comprises the following steps: dissolving waste lithium iron phosphate powder in a sulfuric acid solution, then adding a small amount of a phytic acid solution and ferric sulfate with a corresponding molar weight, precipitating and calcining at a high temperature to obtain dehydrated iron phosphate (FP-PA) with a limited particle size; when the material is applied to synthesis of a lithium manganese iron phosphate positive electrode material, the particle size of the positive electrode material can be effectively controlled, and the specific capacity and cycle performance of a battery are improved. The method is easy to operate and high in repeatability, and a new way is provided for treating waste lithium iron phosphate with economic benefits and excellent performance.

This invention discloses a rare-earth metal gradient-doped polyanionic cathode material, its preparation method, and its application. The molecular formula of the rare-earth metal gradient-doped polyanionic cathode material is Na. 2+2x‑y RE y Fe 2‑x (SO4)3, in the rare earth metal gradient-doped polyanionic cathode material, rare earth metal elements enter the crystal lattice of the polyanionic cathode material in the form of rare earth metal ions, and the doping content of the rare earth metal ions decreases in a gradient along the direction from the crystal lattice surface to the bulk phase. The polyanionic cathode material is an Alluaudite-type sodium iron sulfate cathode material. This invention effectively solves the kinetic mismatch problem of "fast ions but slow electrons" in rate performance by simultaneously optimizing the electronic structure and sodium ion channels through rare earth doping, significantly improving the structural stability of the material under long-cycle and fast-charge-discharge conditions. Simultaneously, the assembled sodium-ion battery exhibits excellent wide-temperature performance.

The present invention discloses a method for removing impurities from waste acid and fully recycling the waste acid. The method comprises the following steps: introducing hydrogen sulfide into the waste acid for a sulfidation reaction, removing arsenic sulfide and mercuric sulfide precipitates formed during the reaction; continuing to introduce hydrogen sulfide for a step-by-step sulfidation reaction, adding an iron-containing substance to adjust the reaction pH and ORP, and recovering the copper, lead, and zinc sulfide slag precipitates formed during the reaction in a step-by-step manner; adding an iron-containing substance for a neutralization reaction, controlling the pH and ORP, promoting the reaction between iron ions and arsenate, and removing the ferric arsenate precipitate formed during the reaction; adding an adsorbent for an adsorption reaction, and removing fluorine-containing and thallium-containing components by adsorption; introducing an oxidant for an oxidative hydrolysis reaction, controlling the degree of hydrolysis, and preparing polyferric sulfate. The present invention utilizes the iron-containing substance to remove impurities from waste acid, thereby achieving deep impurity removal and full resource utilization of waste acid.

The invention discloses a desert steppe grass interspecific synergistic agent and a preparation method and application thereof, and relates to the technical field of synergistic agents, the synergistic agent comprises the following raw materials by weight: 30-40 parts of modified cyanobacteria charcoal, 10-15 parts of a microbial fertilizer, 20-30 parts of an organic fertilizer, 10-20 parts of an inorganic fertilizer, 1-2 parts of a plant growth regulator, and 2-5 parts of a water-retaining agent; the modified blue-green algae charcoal is prepared from the following raw materials in parts by weight: 15-30 parts of ferrous sulfate heptahydrate, 15-30 parts of ferric sulfate hydrate, 200-400 parts of water and 10-20 parts of blue-green algae powder. The synergist provided by the invention can effectively improve the growth efficiency of desert grassland grass planting and effectively improve the treatment effect of degraded grassland.

This invention relates to the field of industrial wastewater treatment technology, specifically a highly efficient treatment method for methionine wastewater, comprising the following steps: Step 1: pH adjustment, adjusting the pH of the methionine wastewater to 6.0-7.0; Step 2: Polyferric sulfate coagulation and sedimentation, adding polyferric sulfate and polyacrylamide to the pH-adjusted wastewater; Step 3: Pre-stage ozone oxidation, passing the supernatant obtained in Step 2 through ozone-containing gas for oxidation treatment; Step 4: Biochemical treatment, subjecting the effluent from Step 3 to a biochemical reaction, sequentially passing through anoxic and aerobic stages; Step 5: Post-stage ozone oxidation, passing the biochemical effluent obtained in Step 4 again through ozone-containing gas for deep oxidation treatment; Step 6: Activated carbon adsorption. The methionine wastewater treated by this invention can significantly reduce TOC concentration and improve COD removal rate. The pH pre-adjustment step effectively reduces the quenching effect of alkalinity on hydroxyl radicals, ensuring the efficiency of subsequent advanced oxidation processes.

The application relates to the technical field of sodium ion batteries, in particular to a sodium ferrosulfate positive electrode material, a preparation method and a positive electrode sheet and a sodium ion battery, wherein the sodium ferrosulfate positive electrode material comprises a sodium ferrosulfate base body, and the surface of the sodium ferrosulfate base body is coated with a carbon coating layer; wherein the sodium ferrosulfate base body is doped with P elements, and the carbon coating layer is doped with N elements. The P elements doped in the sodium ferrosulfate base body and the N elements doped on the carbon coating layer improve the rate performance and the cycle stability of the sodium ferrosulfate positive electrode material.

The application provides a purification and impurity removal method of a crude nickel-cobalt-manganese sulfate solution, and comprises the following steps: (1) adding thiosulfate to the crude nickel-cobalt-manganese sulfate solution to remove copper; (2) adding phosphate and adjusting the pH value to remove titanium, iron and aluminum; (3) adding iron sulfate and adjusting the pH value to remove phosphorus and silicon; (4) adding a bismuth agent and adjusting the pH value to remove chlorine; (5) adding a fluorine agent to remove calcium and magnesium; and (6) adding an ice rock mineral adsorbent to remove fluorine. The method can efficiently remove iron, aluminum, copper, fluorine, phosphorus, titanium, calcium, magnesium, chlorine, silicon and other elements from the crude nickel-cobalt-manganese sulfate solution, and the loss of main metals is low; the high-purity nickel-cobalt-manganese sulfate solution prepared can directly meet the requirements of a battery preparation grade precursor solution, the process is simple, the operation difficulty is low, and the industrialized production can be easily realized, and the method overcomes the shortcomings of the current high-purity nickel-cobalt-manganese sulfate solution preparation method.

This invention provides a method for removing impurities and recovering nickel anolyte from electrolytic nickel. The method includes the following steps: (1) mixing the electrolytic nickel anolyte with liquid alkali, separating the solid and liquid components to obtain nickel hydroxide and filtrate, evaporating the filtrate to obtain sodium sulfate; mixing the electrolytic nickel anolyte with a nickel source to obtain a mixed solution; (2) mixing the mixed solution with barium salt for lead removal; (3) adjusting the pH of the material obtained after lead removal with nickel hydroxide to obtain an arsenic removal solution, mixing the arsenic removal solution with polyferric sulfate for arsenic removal; (4) mixing the material obtained after arsenic removal with an oxidant to obtain an iron removal solution, performing solid-liquid separation on the iron removal solution to obtain lead-, arsenic-, and iron-removed cathode liquid and iron-containing slag, adding sodium sulfate to the lead-, arsenic-, and iron-removed cathode liquid, and reusing it in the electrolytic nickel process. The method of this invention can efficiently and quickly remove lead, arsenic, and iron from electrolytic nickel anolyte and reuse it.

This invention discloses a spherical iron phosphate, its preparation method, and its applications, belonging to the field of iron phosphate preparation technology. The preparation method provided by this invention includes the following steps: mixing ferric sulfate and phosphoric acid in water and then carrying out a hydrothermal reaction; controlling the molar ratio of iron to phosphorus to be greater than 1; after the reaction, adding ammonium dihydrogen phosphate, ensuring that the total molar amount of ammonium dihydrogen phosphate and phosphoric acid is not less than the molar amount of iron, and then carrying out a hydrothermal reaction; after the reaction, sequentially washing, filtering, spray drying, and sintering to obtain the spherical iron phosphate. The spherical iron phosphate obtained using the preparation method of this invention has the characteristics of high tap density, narrow particle size distribution, high specific surface area, high crystallinity, and no severe agglomeration. Lithium iron phosphate materials prepared using this iron phosphate as a precursor can achieve high compaction, low sintering temperature, low powder resistivity, and high specific capacity.

The invention discloses a defluorination agent suitable for defluorination of electronic industrial wastewater as well as a preparation method and a defluorination method of the defluorination agent. The defluorination agent comprises 9-10 wt% of aluminum salt, 0.1-0.2 wt% of ferric salt, 0.6-1.1 wt% of an alkaline regulator and the balance of water, the aluminum salt is selected from one or more of polyaluminum chloride and aluminum sulfate, and the ferric salt is selected from one or more of ferric trichloride, ferric sulfate and polyferric sulfate. The fluorine removal agent provided by the invention can realize that the fluorine concentration of discharged water is lower than 1mg / L through one-stage / two-stage fluorine removal under a low-fluorine, medium-fluorine or high-fluorine water inlet condition, the optimal pH condition of reaction is reduced, the acid-base and agent use cost is saved, and meanwhile, the fluorine removal agent is simple in preparation method and can be applied to large-scale popularization and production.