273results about "Iron sulfates" patented technology

The invention relates to the technical field of water treatment agent preparation and environmental governance material processing, in particular to polymeric ferric sulfate and a preparation method thereof.The preparation method comprises the steps that steam condensation recycled water of a thermal power plant of an aluminum factory is mixed with ferrous sulfate and concentrated sulfuric acid to form a reaction solution, oxygen is introduced for an oxidative polymerization reaction, and a liquid intermediate is generated; gradient cooling is carried out on the liquid intermediate to control the molar ratio of ferric ions to hydroxyl, and a porous solid precursor is formed through concentration and closed aging; crushing the precursor, performing graded drying by adopting a rotary kiln and flash drying, and synchronously spraying a hydrophobic modifier to reduce the surface hydroxyl activity; the powdery product is secondarily dried in a nitrogen inert environment, and moisture absorption and agglomeration are inhibited. The invention solves the problems of mixed crystal forms, delayed release of effective components and secondary pollution in the traditional process. The obtained product is uniform in crystal form, concentrated in particle size distribution, remarkably improved in dissolution rate and storage stability, and suitable for black and odorous water body treatment and industrial sewage treatment.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a modified sodium ferric sulfate positive electrode material as well as a preparation method and application thereof. The chemical structural formula of the modified sodium ferric sulfate positive electrode material is Na < 2 + 2x > (Fe < 1-a-b > MaMb < 2-x > (SO4) z (PO4) < 3-z, a is more than 0 and less than 1, b is more than 0 and less than 3, z is more than 0 and less than 3, Ma and Mb are transition metal elements, and Ma is Ni; and Mb is Zn. The transition metal element is introduced and the doping proportion is controlled, so that fine regulation and control on the material performance can be realized, the conductivity and the ion diffusion rate of the positive electrode material are improved, and the structural stability and the air stability of the material are enhanced; the problems of slow Na < + > diffusion kinetics, poor crystallinity and poor material air stability of the sodium ferric sulfate positive electrode material are solved, and a new possibility is provided for the development of a sodium ion battery technology.

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 belongs to the technical field of chemical production automation, and particularly relates to a ferrous sulfate oxidation production automation system and a control method thereof. The ferrous sulfate quantitative feeding subsystem comprises a constant mass feeding module which is used for accurately controlling the feeding amount of ferrous sulfate through a high-precision scale; the parameter setting module is used for providing a parameter input interface; the hydrogen peroxide quantitative feeding subsystem comprises a flow accumulation module which is used for obtaining a hydrogen peroxide volume parameter through instantaneous flow integration; the constant-volume feeding module is used for accurately controlling the feeding amount of hydrogen peroxide through a flow meter; the automatic stirring subsystem comprises an automatic stirring module; the automatic stirring module realizes automatic start and stop of a stirrer, so that slurry dissolution can be guaranteed to the greatest extent, and the stirrer can be protected from idling; the temperature control subsystem comprises a temperature control module which is used for accurately controlling the temperature of the reaction kettle. The temperature control device is used for solving the problems of accurate feeding and accurate temperature control in the prior art.

The invention belongs to the technical field of battery materials, and mainly relates to a method for preparing an inorganic carbon composite sodium ferric sulfate positive electrode material under the assistance of reduced iron powder and a sodium ion battery. The method comprises the following steps: adding sodium sulfate, ferrous sulfate and reduced iron powder into deionized water, stirring until the sodium sulfate and the ferrous sulfate are completely dissolved, and separating the residual reduced iron powder to obtain a sodium ferric sulfate precursor solution; mixing the sodium ferric sulfate precursor solution with an inorganic carbon source, stirring, and carrying out spray drying to obtain an inorganic carbon composite sodium ferric sulfate positive electrode material precursor; and sintering the precursor in an inert atmosphere to obtain the inorganic carbon composite sodium ferric sulfate positive electrode material. According to the method, ferric iron is reduced into ferrous iron with electrochemical activity by using the reducing iron powder, and the inorganic carbon source is used as the conductive agent, so that the problem of poor conductivity of the material caused by incomplete decomposition of the organic carbon source in the sintering process is avoided, the pure-phase sodium ferric sulfate positive electrode material with high conductivity is synthesized and prepared, and the electrochemical performance of the material is improved.

The invention provides a sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material and a preparation method thereof.The preparation method comprises the steps that raw materials including a reducing agent, an iron source, a sodium source and a carbon source are added into absolute ethyl alcohol to be stirred, sanded and mixed, and after obtained slurry is subjected to spray drying, the slurry is sintered and cooled in the argon atmosphere to obtain the sodium ferric sulfate / carbon composite material; mixing the sodium ferric sulfate / carbon composite material dispersion liquid with the sodium vanadium fluorophosphate precursor solution, performing hydrothermal reaction, centrifuging, washing and drying to obtain the sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material. According to the preparation method, a sodium vanadium fluorophosphate coating layer is generated on the surface of sodium ferric sulfate in situ by combining a low-temperature solid-phase method with a hydrothermal method, so that the sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material is obtained, the electronic conductivity of the composite material is greatly improved, and the sodium ion diffusion rate is promoted by coating of sodium vanadium fluorophosphate; fe2 + is prevented from being oxidized into Fe3 + due to direct contact between the sodium ferric sulfate and air, so that the air stability of the sodium ferric sulfate is improved.

The utility model discloses a ferrous sulfate monohydrate preparation component based on two-stage high-temperature dehydration, comprising a drying drum and a combustion chamber, wherein the head of the drying drum is higher than the tail and can rotate, the drying drum is formed by connecting a first drying drum and a second drying drum, the tail of the first drying drum is connected to the head of the second drying drum by a connecting assembly and the connecting assembly cannot rotate, the combustion chamber comprises a first combustion chamber and a second combustion chamber, the first combustion chamber feeds high-temperature flue gas into the first drying drum through the connecting assembly, and the second combustion chamber is close to the tail of the second drying drum and feeds high-temperature flue gas into the second drying drum. The utility model feeds high-temperature flue gas into the two drying drums through two combustion chambers respectively, so as to facilitate segmented temperature control to achieve segmented dehydration of raw materials, obtain ferrous sulfate monohydrate with higher purity, and finally achieve the purpose of easy temperature control, high product purity and high production efficiency.

The invention provides a method for recovering valuable metals from sulfuric acid process titanium white waste acid through steel slag treatment. The method comprises the following steps: recovering to obtain ferrous sulfate heptahydrate crystals; s2, recovering Sc metal, and extracting the filtrate in the step S1 to obtain a first loaded organic phase and a first raffinate; the first loaded organic phase is washed with alkali liquor, and a second loaded organic phase and washing water are obtained through reverse extraction; treating the washing water to obtain titanium phosphate; back-extracting the second loaded organic phase by using alkali liquor, carrying out filter pressing to obtain crude Sc (OH) 3, and refining to obtain scandium oxide; extracting the first raffinate to obtain a third loaded organic phase and a second raffinate, pickling the third loaded organic phase, reversely extracting with ammonia water, adding phosphoric acid for reaction, and treating to obtain titanium phosphate; and steel slag is added into the second raffinate for neutralization leaching and hydrolysis vanadium precipitation, vanadium-rich slag is obtained through filtering, and then the vanadium electrolyte is prepared. According to the method, iron is separated through crystallization, scandium and titanium are separated through extraction, vanadium-rich slag is separated through neutralization and precipitation, and efficient utilization of resources is achieved.

The invention discloses a method for obtaining copper and ferrous sulfate from low-grade sulfur-oxygen mixed iron-copper ore, which comprises the following steps: dry-grinding the iron-copper ore, performing low-temperature roasting modification on the dry-ground ore powder to obtain modified ore powder and roasting flue gas, collecting and cooling the roasting flue gas to obtain a crystallization product, and returning the crystallization product to roasting for recycling. The modified mineral powder is subjected to enhanced acid leaching, the acid leaching condition is controlled, and acid leaching residues and leachate are obtained; extracting and reversely extracting the leachate, controlling extraction and reverse extraction conditions to obtain raffinate, copper-rich liquid and an organic phase, recycling the organic phase after acid pickling and iron removal, performing flocculating settling on the raffinate to obtain supernate and settling slag, and performing evaporative crystallization treatment on the supernate to obtain ferrous sulfate. The method can efficiently recover copper in the refractory low-grade sulfur-oxygen mixed iron-copper ore, fully utilizes iron resources, and has the characteristics of simple process, high applicability, high copper recovery rate and the like. And the follow-up emulsification risk of the copper extraction agent can be effectively reduced, and follow-up recovery of copper is facilitated.

The invention relates to the technical field of sodium ion battery positive electrode materials, and discloses a process method for preparing a sodium ferric sulfate composite positive electrode material from a crystal water-free precursor and a sodium ion battery. The problems of low crystallinity of Na < 2 + > 2 < delta > Fe < 2-delta > (SO4) 3 and easy oxidation of Fe < 2 + > caused by water vapor generated when the Na2Fe (SO4) 2.4 H2O precursor is heated and hydrated are solved. On the basis, aiming at the defect of poor electronic conductivity of Na < 2 + 2 > < delta > Fe < 2-delta > (SO4) 3, the invention provides the Na < 2 + 2 > < delta > Fe < 2-delta > (SO4) 3 / C composite positive electrode material with improved conductivity, and the composite positive electrode material can show excellent high rate capacity and long cycle stability at room temperature and in high and low temperature environments, and has a relatively good prospect in the field of novel energy storage.

The invention relates to the technical field of battery material recovery, and particularly discloses a method for efficiently recovering lithium and ferrous sulfate heptahydrate in retired lithium iron phosphate through total leaching and green impurity removal. Comprising the following steps: 1, adding strong base and a carbon source into black powder, and calcining at high temperature in an inert atmosphere; step 2, dissolving in pure water after calcining, and carrying out suction filtration to obtain a lithium salt solution and ferrous hydroxide; 3, sulfuric acid is added into ferrous hydroxide for suction filtration, and graphite and a ferric salt solution are obtained; drying the ferric salt solution to obtain ferrous sulfate heptahydrate; step 4, adding alkali into the lithium salt solution to obtain a purified lithium salt solution; 5, introducing carbon dioxide into the purified lithium salt solution, and adding alkali to generate lithium carbonate precipitate; and 6, finally carrying out heat preservation, suction filtration, washing and drying to obtain a lithium carbonate finished product. The technical problems that in the prior art, a traditional decommissioned lithium iron phosphate battery grading recycling technology is complex in production process, more waste liquid pollution is generated, and the production cost is relatively high are solved.

The invention provides a method for preparing ferrous sulfate from iron-containing solid waste, and relates to the field of solid waste treatment. The method for preparing ferrous sulfate from the iron-containing solid waste comprises the following steps: mixing concentrated sulfuric acid and the iron-containing solid waste, and curing in a reducing atmosphere or a protective atmosphere to obtain a cured material; the cured material is subjected to water leaching and centrifugal separation, and silicon-containing slag and leachate are obtained; carrying out deepening treatment on the silicon-containing slag to obtain white carbon black; the leachate and iron powder are mixed for a reduction reaction, then a vulcanizing agent is added for vulcanization, precipitation and impurity removal, and copper sulfide slag and a ferrous sulfate solution are obtained through solid-liquid separation; treating the copper sulfide slag to recover valuable metals; and crystallizing the ferrous sulfate solution to obtain ferrous sulfate crystals. According to the method for preparing the ferrous sulfate from the iron-containing solid waste, low-cost, short-process and high-efficiency treatment of the iron-containing solid waste is achieved, and the ferrous sulfate product is obtained.

The invention discloses a method for separating and recycling phosphorus, iron and lithium in battery black powder, and relates to the technical field of battery recycling. The method comprises the following steps: carrying out acid leaching on battery black powder to obtain a battery black powder leaching solution and filter residues; an oxidizing agent is added into the battery black powder leaching solution, the pH of the solution is adjusted to 1.8-2.5, solid-liquid separation is conducted after the reaction is completed, and iron phosphate sediment and a lithium-containing solution are obtained; adjusting the pH value of the lithium-containing solution to 10-12, and carrying out solid-liquid separation after the reaction is completed to obtain a metal precipitate and a lithium sulfate solution; dissolving the iron phosphate precipitate in a sulfuric acid solution, adding a reducing agent to reduce ferric iron into ferrous iron, separating out ferrous sulfate by adopting an alcohol precipitation method or an ammonium sulfate crystallization method, and performing solid-liquid separation after the reaction is completed to obtain ferrous sulfate precipitate or ammonium ferrous sulfate crystals and mother liquor; and evaporating and concentrating the mother liquor, and extracting to obtain a phosphoric acid solution. According to the method, the three elements of phosphorus, iron and lithium in the battery black powder can be recycled, and the environmental problem caused by stacking of the lithium extraction slag can be avoided.

The invention relates to the field of secondary batteries, in particular to a sodium ion battery composite positive electrode material and a preparation method thereof. The preparation method comprises the following steps: preparing a layered transition metal oxide positive electrode material, mixing the layered transition metal oxide positive electrode material with a polyanion raw material, spray-drying, sintering and the like. Compared with the prior art, the preparation method has the advantages that the layered transition metal oxide positive electrode material is synthesized firstly, the layered transition metal oxide positive electrode material and the polyanion raw material are mixed in the early stage, and the spray drying technology is adopted, so that the two materials can be uniformly dispersed on the microscopic level; the uniform distribution is maintained in the subsequent sintering process, the phase splitting and segregation phenomena of the material are prevented, the component uniformity of the composite positive electrode material is ensured, and the prepared sodium ion battery has higher compaction density, high capacity, high energy density and more stable performance during use.

The invention discloses a method for separating and recycling phosphorus, iron and lithium in battery black powder, and relates to the technical field of battery recycling. The method comprises the following steps: mixing and leaching battery black powder and sulfuric acid, and filtering to obtain a leaching solution; the pH of the leachate is controlled, ferrous sulfate in the solution is separated out through alcohol substances or ammonium sulfate, and ferrous sulfate precipitates or ammonium ferrous sulfate crystals and mother liquor are obtained after filtration; evaporating and concentrating the mother liquor, adding an impurity removing agent into the mother liquor, and extracting to obtain a phosphoric acid solution and a lithium-containing solution; after phosphoric acid is supplemented into the lithium-containing solution, the pH is adjusted to be 8-10, and battery-grade lithium phosphate precipitates are obtained. According to the method, iron in the leachate is separated out firstly, and the subsequent impurity removal difficulty is greatly reduced, so that recycling of three elements including phosphorus, iron and lithium in the battery black powder is facilitated, and the environmental problem caused by stacking of lithium extraction residues can be avoided.

The invention discloses a method and a system for recovering solid residues in titanium dioxide production by a fluorination method. The recovery method comprises the following steps: mixing and reacting solid residues obtained after titanium dioxide is produced by a fluorination method with concentrated sulfuric acid with the concentration of 95-100wt% at the temperature of 25 DEG C or above, so as to obtain ferric sulfate and hydrogen fluoride. According to the method for recycling the solid residues in the titanium dioxide produced through the fluorination method, FeF3 in the solid residues can be converted into Fe2 (SO4) 3 and HF to be recycled, waste is turned into wealth, H2SO4 used in the recycling method is wide in source, the requirement for technological conditions is low, pollution to the environment is small, and the method is suitable for industrial production. And clean production can be realized while the process energy consumption is reduced.

The invention belongs to the technical field of secondary batteries, and particularly relates to a sodium ferric sulfate positive electrode material as well as a preparation method and application thereof. The preparation method of the sodium ferric sulfate positive electrode material comprises the following steps: S1, mixing a sodium source, an iron source, a sulfur source, an antioxidant, multilayer graphene oxide and water to obtain spray slurry; the number of layers of the multi-layer graphene oxide is 10-50; s2, performing spray drying on the spray slurry to obtain a spray material; and S3, sintering and crushing the spray material obtained in the step S2 to obtain the sodium ferric sulfate positive electrode material. The sodium ferric sulfate positive electrode material prepared by the method has good compaction density, and the energy density and the cycling stability of the sodium ferric sulfate positive electrode material can be improved through the compaction density.

The invention relates to the technical field of battery recovery, and particularly discloses a recovery method of waste lithium iron phosphate and a lithium ion secondary battery. The recovery method of the waste lithium iron phosphate comprises the following steps: leaching acid liquor, and carrying out solid-liquid separation to obtain acid leaching liquor and a regenerated negative electrode material; cooling and crystallizing, and carrying out solid-liquid separation to obtain first iron-removed slag and first iron-removed liquid; oxidizing, adjusting pH, removing iron, and carrying out solid-liquid separation to obtain second iron-removed slag and second iron-removed liquid; adjusting the pH to precipitate lithium phosphate, and carrying out solid-liquid separation to obtain first lithium phosphate slag and lithium precipitation mother liquor; adding a lithium source into the lithium precipitation mother solution, and carrying out solid-liquid separation after reaction to obtain second lithium phosphate slag and a phosphorus removal solution; and evaporating and concentrating the dephosphorized solution to obtain a by-product salt. By implementing the invention, the recovery of each useful component can be realized.

The invention discloses a preparation method of iron phosphate with a high iron-phosphorus ratio. According to the method, a small amount of iron source is added in the process of dissolving and recrystallizing amorphous-state iron phosphate in the aging process, and the part of iron source enters crystalline-state iron phosphate, so that the utilization rate of a P element in a reaction system is increased, and meanwhile, the iron-phosphorus ratio of the prepared iron phosphate is increased.

The invention belongs to the technical field of titanium dioxide production by a sulfuric acid method, and particularly relates to a ferrous sulfate heptahydrate separating and washing process and a vertical centrifugal machine. According to the separation and washing process, a solid-liquid mixture transfer barrel, a vertical centrifugal machine, a ferrous collecting hopper, a humidifying and mixing conveyor, a ferrous spiral feeder, a horizontal pushing centrifugal machine, a ferrous spiral discharging machine, a titaniferous solution storage barrel, a light washing solution storage barrel, a concentrated washing solution storage barrel, a light washing solution conveying pump, a concentrated washing solution conveying pump and a titaniferous solution conveying pump are included. According to the invention, the investment is greatly reduced, and the plant area required by equipment installation is also greatly reduced; according to the capacity configuration of annual production of 30,000 tons of titanium dioxide, the required plant area is 150m, and the investment of core equipment is about 1500,000 yuan.

The invention relates to a method for separating iron, vanadium and titanium dioxide in vanadium titano-magnetite or titanium concentrate through a wet method, and belongs to the technical field of chemical engineering. The method comprises the following steps: (a) mixing vanadium titano-magnetite or titanium concentrate with sulfuric acid with the concentration of 22-30wt.% to obtain mixed slurry; (b) treating the mixed slurry at 150-200 DEG C and 2-4 MPa under the condition that the Reynolds number is gt; reacting in a turbulent flow state of 4000, so that non-titanium elements are dissolved to generate sulfate; (c) carrying out solid-liquid separation on the reaction product in the step (b) to obtain a high-grade titanium-rich material and waste liquid; (d) the titanium-rich material reacts with a sodium hydroxide solution, silicon in the titanium-rich material is removed, and a sodium silicate solution is generated; and (e) reacting the silicon-removed titanium-rich material with a hydrochloric acid solution with the mass concentration of less than 15%, cleaning, carrying out solid-liquid separation, and calcining to obtain anatase or rutile titanium dioxide. According to the method, all iron, vanadium and titanium elements in the vanadium-titanium-iron concentrate and the titanium concentrate are recycled.

The invention relates to the technical field of lithium ion batteries, and provides a method for preparing lithium iron phosphate by using a titanium dioxide byproduct ferrous sulfate and application. The invention relates to a method for preparing lithium iron phosphate by using a titanium dioxide byproduct ferrous sulfate, which comprises the following steps: dissolving the titanium dioxide byproduct ferrous sulfate, adding a purifying agent for purification treatment, and filtering to obtain a purified ferrous sulfate solution; the purified ferrous sulfate solution serves as electrolyte, Fe < 2 + > is partially oxidized into Fe < 3 + >, phosphoric acid is added into the obtained mixed valence iron solution, the pH is adjusted, and iron phosphate precursor slurry is formed through aging; mixing the iron phosphate precursor slurry with an ethanolamine-water mixed solution of lithium hydroxide, and carrying out a reaction in a microwave reactor to obtain a lithium iron phosphate precursor suspension; and crystallizing the lithium iron phosphate precursor, and simultaneously introducing a carbon source steam and a silicon source steam to carry out gas-phase surface modification to obtain the lithium iron phosphate material. According to the invention, the raw material purity is improved, the powder structure is improved, and the long-cycle stability is improved.

The disclosure discloses a method for preparing a battery-grade nickel-cobalt-manganese sulfate solution from low nickel matte. The method includes the following steps: grinding low nickel matte, then adding the ground low nickel matte to concentrated sulfuric acid, and carrying out atmospheric pressure leaching to obtain a first slag phase and a first liquid phase; carrying out evaporation concentration-cooling crystallization on the first liquid phase to obtain ferrous sulfate crystals; adding concentrated sulfuric acid to the first slag phase, and carrying out oxygen pressure leaching to obtain a second slag phase and a second liquid phase; adjusting pH of the second liquid phase to 3-4 to generate a precipitate, and removing the precipitate by filtration to obtain a filtrate; carrying out adsorption treatment on the filtrate by adopting chelating resin; washing the adsorbed chelating resin with a first sulfuric acid solution to obtain a washing solution containing Mg and Mn, and then washing the chelating resin with a second sulfuric acid solution to obtain a nickel-cobalt sulfate solution; and mixing the nickel-cobalt sulfate solution with the washing solution containing Mg and Mn to obtain the nickel-cobalt-manganese sulfate solution. According to the method of the disclosure, the battery-grade nickel-cobalt sulfate solution is prepared from the low nickel matte as a raw material, so that the recovery rate of nickel and cobalt is increased, and the acid consumption is reduced.

The invention discloses an electroplating sludge iron resource recovery method based on acid leaching-resin selective adsorption, and relates to the field of dangerous solid waste resource treatment.The electroplating sludge iron resource recovery method comprises the following steps that S1, collected electroplating sludge and sodium salt are evenly mixed, roasted, cooled, washed and filtered, and washing liquid and filter residues are obtained; s2, adding water into the filter residues obtained in the S1, uniformly mixing, then mixing with an acid solution, carrying out an acid leaching reaction, and carrying out solid-liquid separation to obtain an acid leaching solution; according to the electroplating sludge iron resource recycling method based on acid leaching-resin selective adsorption, selected specific chelating resin is large in iron ion adsorption capacity and excellent in selectivity under the low pH, competitive interference of coexisting ions such as Cu < 2 + > can be effectively overcome, and the iron recycling rate can reach 99% or above; the adsorption step is carried out under the strong acidic condition and is matched with the characteristics of the electroplating sludge pickle liquor, the pH does not need to be greatly adjusted, the process is simplified, and the cost is reduced.

The invention provides a treatment method for hydrofluoric acid-sulfuric acid process tantalum-niobium tailings. The treatment method comprises the following steps that the tantalum-niobium tailings obtained through hydrofluoric acid-sulfuric acid method smelting are mixed with a dilute sulfuric acid solution, the mixture is stirred to react for 30-300 min at the temperature of 40-80 DEG C, and lixivium and washing residues are obtained through heat preservation and filtration; mixing the leaching solution with iron powder for reduction reaction, and filtering to obtain a purified solution; carrying out cooling crystallization treatment on the purified liquid, and filtering to obtain crude ferrous sulfate and crystallization mother liquor; and adjusting the pH value of the crystallization mother liquor to 2.0-6.0 by using a pH regulator, mixing with a defluorinating agent for defluorination reaction, and filtering to obtain a fluorine-containing compound and a recycled mother liquor. According to the method, iron, fluorine and other resources in the tantalum-niobium tailings can be effectively utilized, and meanwhile reduction and harmlessness of the tantalum-niobium tailings are achieved.

A method for full-chain integrated recovery of iron-aluminum slag produced during battery recycling. The method comprises the following steps: (1) mixing iron-aluminum slag with water, carrying out pressurized leaching with water, so as to obtain water leaching residues and a water leachate, and using water to wash the water leaching residues, so as to obtain a lithium-rich solution; (2) evaporating and concentrating the lithium-rich solution, then carrying out low-temperature crystallization, performing solid-liquid separation to obtain sodium sulfate crystals and a lithium precipitation mother liquor, mixing the lithium precipitation mother liquor with sodium carbonate and performing solid-liquid separation to obtain lithium carbonate; (3) mixing the water leaching residues with the mother liquor, carrying out pressurized alkali leaching and performing solid-liquid separation to obtain alkali-leaching residues and a leachate of alkali leaching; and (4) mixing the leachate of alkali leaching with an impurity remover, and performing solid-liquid separation to obtain calcium fluorophosphate impurity precipitate and an impurity-removed purified solution, and crystallizing the impurity-removed purified solution, so as to obtain aluminum hydroxide crystals and a mother liquor for recycling. Pressurized leaching of iron-aluminum slag generated during battery recycling achieves comprehensive resource utilization of the hazardous solid waste iron-aluminum slag.

The invention discloses a method for extracting and recovering scandium and copperas from a scandium-containing solution without emulsification. The method comprises the following steps: (1) leaching scandium-containing waste residues by using titanium white waste acid to obtain a scandium-containing leachate; (2) a certain amount of iron powder is added into the scandium-containing leachate, after the iron powder reacts completely, the solution is put into a low-temperature constant-temperature tank to be crystallized, suction filtration is conducted after crystallization is completed, and iron-removed leachate and copperas are obtained; and (3) extracting the iron-removed leachate by using a P204-TBP extraction system to obtain a scandium-containing organic phase, wherein the scandium-containing organic phase is not emulsified in the process.

The invention relates to a method for high-value utilization of waste lithium iron phosphate battery lithium extraction slag, and belongs to the technical field of waste lithium ion battery resource utilization. The method comprises the following steps: S1, mixing the lithium iron phosphate lithium extraction slag with a low-concentration sulfuric acid solution in proportion, carrying out countercurrent washing, carrying out solid-liquid separation, carrying out acid dissolution on a solid, carrying out gradient recycling on a washing solution, and carrying out resin adsorption and reverse osmosis treatment on a high-impurity washing solution for recycling; s2, reacting the pretreated solid with medium-concentration sulfuric acid, reducing a dissolved solution by using iron powder, then carrying out solid-liquid separation to obtain a first batch of ferrous sulfate heptahydrate, adding concentrated sulfuric acid into mother liquor, carrying out secondary crystallization, then carrying out solid-liquid separation, and recrystallizing the obtained solid by using washing wastewater to obtain a second batch of ferrous sulfate heptahydrate; s3, recovering sulfuric acid by adopting a membrane treatment method, and recovering phosphoric acid from residual mother liquor by adopting an extraction method; or directly treating the lithium iron phosphate waste residue. According to the method, efficient separation and recovery of iron and phosphorus resources and full-component high-value utilization of the lithium iron phosphate lithium extraction slag are realized.

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 resourceful treatment method for stainless steel pickling waste liquid and waste water. The waste liquid is divided into high-concentration waste liquid and low-concentration waste liquid according to the acid concentration and the salt concentration to be treated respectively. Sequentially recovering gypsum, chromic hydroxide, nickel sulfide, ferrous hydroxide and manganese-rich slag from the low-concentration waste liquid through gradient precipitation; and neutralizing free acid from the high-concentration waste liquid by using ferrous hydroxide generated in a low-concentration section, cooling and crystallizing to recover ferrous sulfate, deeply removing nickel by using nickel sulfide generated in the low-concentration section, and precipitating to recover chromium hydroxide. In the whole process, generation of ferric iron is strictly controlled, and high-value productization recovery of free acid and all metals is achieved. The method has the advantages of low medicament consumption, high metal recovery rate, high product value, no secondary pollution and the like.