91results about "Iron sulfates" patented 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 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 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 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 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 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 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 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.

The invention discloses a ferrous sulfate purification method and a ferrous sulfate purified product, and the method comprises the following steps: dissolving a titanium dioxide by-product in deionized water to obtain a ferrous sulfate saturated solution; under the condition that reducing gas is introduced into the ferrous sulfate saturated solution, mixing sodium sulfide with the ferrous sulfate saturated solution, and filtering to obtain a first purified solution; mixing sodium sulfide with the first purified solution, and filtering to obtain a second purified solution; and carrying out concentration crystallization on the second purified solution, and carrying out suction filtration and drying to obtain a ferrous sulfate purified product. Iron powder does not need to be added, oxidation of ferrous ions is inhibited through reducing gas, sodium sulfide is added in stages to enable impurities with high activity to react to generate sulfide precipitates, the sulfide precipitates are filtered, the content of impurities such as titanium ions, magnesium ions, manganese ions and calcium ions is greatly reduced, the impurity removal effect is good, and finally concentration and crystallization are conducted through solubility difference. The purification purity of the ferrous sulfate purified product is generally as high as 99% or above.

The invention discloses a method for preparing battery-grade ferrous sulfate from a titanium dioxide byproduct ferrous sulfate, which comprises the following steps: (1) heating and dissolving the titanium dioxide byproduct ferrous sulfate in a solvent to form a ferrous sulfate supersaturated solution; (2) sequentially adding iron powder and sulfuric acid into the ferrous sulfate supersaturated solution, and carrying out reduction reaction; (3) adding a chelating agent into the solution obtained in the step (2), mixing, filtering, cooling, and carrying out solid-liquid separation to obtain recrystallized ferrous sulfate crystals and recrystallized saturated mother liquor; and (4) heating and dissolving the recrystallized ferrous sulfate crystal into a supersaturated solution by using a solvent, cooling and crystallizing, and repeating the recrystallization step to obtain the battery-grade ferrous sulfate. According to the method, a chemical chelation method and a recrystallization method are combined, sodium lignin sulfonate is added into the mother liquor as a chelating agent before the first recrystallization, the sodium lignin sulfonate and metal impurity ions form a stable compound, meanwhile, enrichment of the impurity ions in the mother liquor circulation process is avoided, and the purity of ferrous sulfate crystals is improved.

There is provided a method for producing ferrous sulphate and phosphoric acid comprising treating ferrous phosphate with sulphuric acid for obtaining ferrous sulphate and phosphoric acid. Additionally, there is provided a use of sulphuric acid for treating ferrous phosphate for obtaining ferrous sulphate and phosphoric acid.

The invention belongs to the technical field of titanium dioxide production waste resource utilization and inorganic polymeric flocculant preparation, and discloses a closed-loop process for preparing artificial rutile and co-producing polymeric ferric sulfate by using titanium dioxide primary washing waste acid. The method solves the problems of low resource utilization rate of titanium dioxide primary washing waste acid, high acid consumption in preparation of artificial rutile and high production cost of polyferric sulfate in the prior art. Comprising the following steps: pretreatment of titanium dioxide primary washing waste acid, reduction pretreatment of ilmenite, preparation of artificial rutile by leaching refined waste acid and reduced ilmenite, recovery of high-iron-content mother liquor, preparation of polyferric sulfate by oxidation-polymerization of the mother liquor, and cyclic utilization of washing water. The grade of the prepared artificial rutile TiO2 is greater than or equal to 92%, and the polyferric sulfate meets the national standard requirement; the waste acid resource utilization rate is larger than or equal to 98%, the comprehensive cost of the two products is reduced by 25-30%, and the method is suitable for waste resource utilization and fine chemical product collaborative production of sulfuric acid method titanium dioxide enterprises.

The invention discloses a method for separating calcium, silicon, iron and aluminum and enriching titanium by combining titanium white waste acid and red mud, which comprises the following steps: adding antimony powder into concentrated sulfuric acid, heating, dissolving, cooling, adding a sodium dihydrogen phosphate dihydrate liquid (the liquid is formed by heating solid sodium dihydrogen phosphate dihydrate to 60 DEG C higher than the melting point of the sodium dihydrogen phosphate dihydrate), stirring, filtering, washing and drying to obtain the product. Antimony phosphate powder is obtained. The synthesis method is easy to operate, low in requirement on synthesis equipment, free of high-temperature reaction, short in time consumption, high in efficiency and high in product purity.

The invention discloses a countercurrent crystallization production process for reducing the content of impurities such as magnesium (Mg), manganese (Mn) and titanium (Ti) in ferrous sulfate heptahydrate, and belongs to the technical field of purification of inorganic compounds. According to the process, through two-stage design of'system initialization and first-batch material treatment 'and'continuous countercurrent crystallization production', by utilizing cooperative countercurrent cooperation of a dissolving kettle, a crystallization kettle, a centrifugal machine and a multi-stage mother liquor tank, cascade recycling of mother liquor and repeated recrystallization and purification of the materials are realized. According to the process, thousands of ppm of Mg, fifty hundred ppm of Mn and forty ppm of Ti in the ferrous sulfate heptahydrate crude product can be reduced to be smaller than or equal to 180 ppm, smaller than or equal to 40 ppm and smaller than or equal to 25 ppm respectively, meanwhile, the solvent water consumption is reduced by 40% or above, mother liquor emission is reduced, and the process has the advantages of being high in industrial continuity and automation degree and suitable for large-scale production of the low-impurity ferrous sulfate heptahydrate product.

The invention relates to the technical field of industrial solid waste resource utilization and chemical product preparation, and particularly discloses a preparation process for producing ferrous sulfate by utilizing tailings. According to the process, iron-rich tailings (such as pyrite acid-making cinder and titanium dioxide production byproduct ferrous sulfate) are used as main raw materials, and the high-purity ferrous sulfate heptahydrate (FeSO3.7H2O) product is prepared through the steps of crushing and grinding, acid leaching reaction, reduction treatment, purification and impurity removal, cooling crystallization, centrifugal separation, drying and the like. The method is characterized in that the sulfuric acid concentration, the reaction temperature and the liquid-solid ratio in the acid leaching stage are optimized, a specific reducing agent (such as iron powder or pyrite) is introduced, it is ensured that iron elements are efficiently dissolved out in a divalent form, and meanwhile harmful impurities such as heavy metal and arsenic are effectively removed through a step-by-step purification method. According to the method, high-added-value resource utilization of the industrial solid waste is achieved, the technological process is simple, the cost is low, the product purity is high, the problem of environmental pollution caused by tailing stockpiling is solved, and remarkable economic benefits and environmental benefits are achieved.

Disclosed are a pure-phase polyanionic sulfate sodium ion battery positive electrode material and a preparation method therefor. The chemical general formula of the pure-phase polyanionic sulfate sodium ion battery positive electrode material is NaxMyAzSO4, wherein M is one or two or more of Mn, Fe, Co, Ni, Cu, and / or Zn, A is one or two or more of Li, K, and / or Na, and the value ranges of variables are: 0.75≤x≤0.85, 0.52≤y≤0.58, 0<z≤0.1, and x+2y+z=2. The pure-phase polyanionic sulfate sodium ion battery positive electrode material has the characteristics of good structural stability, excellent rate performance, good cycle performance, simple preparation method, and low cost.

The invention provides a purification method of high-calcium-magnesium ferrous sulfate and a ferrous sulfate product, and the purification method of the high-calcium-magnesium ferrous sulfate comprises the following steps: S1, preparing the high-calcium-magnesium ferrous sulfate into a supersaturated high-calcium-magnesium ferrous sulfate solution; s2, adjusting the pH value of the supersaturated high-calcium-magnesium ferrous sulfate solution to 1.5-2.5 to obtain an acidified supersaturated high-calcium-magnesium ferrous sulfate solution; and S3, adding a scale inhibitor into the acidified supersaturated high-calcium-magnesium ferrous sulfate solution, sequentially carrying out cooling crystallization and centrifugal separation, and collecting crystals to obtain ferrous sulfate. According to the method disclosed by the invention, the high-calcium-magnesium ferrous sulfate is subjected to impurity removal by adopting a scale inhibitor chelated calcium and magnesium and a recrystallization method, the obtained ferrous sulfate crystal is high in purity, more than 90% of calcium and magnesium can be removed, and the ferrous sulfate can be directly used for synthesizing battery-grade iron phosphate after being dissolved.

A method is provided for inputting thermal energy into a fluid medium in a manufacturing method using at least one rotating device, comprising a casing having at least one inlet and at least one outlet, a rotor having at least one row of rotor blades arranged around a rotor hub attached to a rotor shaft, and a stator configured as an assembly of fixed vanes positioned at least upstream of the at least one row of rotor blades. The method imparts an amount of thermal energy to the flow of the fluid medium guided along a channel created inside the casing between the inlet and the outlet by a series of energy conversions that occur as the flow of the fluid medium passes through the fixed vanes and at least one row of rotor blades, respectively. The method comprises incorporating the at least one rotating device into a manufacturing facility configured to perform a material manufacturing method, such as producing titanium oxide, mineral wool, gypsum, wood pulp and paper, cathodes and anodes, or rapidly dried chemicals at a temperature essentially of about 500°C or above, and conducting an input amount of energy to the at least one rotating device incorporated into the heat consumption method facility, wherein the input energy includes electrical energy. Further provides rotating devices and related uses.

The invention belongs to the technical field of metallurgy, and particularly discloses a method for extracting gold from refractory iron-sulfur-gold concentrate by a wet process, which comprises the following steps: smelting the refractory iron-sulfur-gold concentrate by a pyrogenic process to obtain iron matte slag rich in gold and silver; the method comprises the following steps: crushing, ball-milling and slurrying the iron matte slag, introducing rich oxygen, carrying out pressure leaching under an acidic condition, and carrying out liquid-solid separation to obtain oxygen pressure leaching liquid and oxygen pressure leaching slag; cooling and crystallizing the oxygen pressure leachate to recover ferrous sulfate heptahydrate, and periodically vulcanizing, precipitating and recovering other valuable metals through crystallization mother liquor; sulfur, sulfur concentrate slag and gold and silver slag are separated from oxygen pressure leaching slag through conventional flotation, the sulfur concentrate slag is returned to the pyrogenic smelting process, and gold and silver products can be obtained by dissolving the gold and silver slag through aqua regia and selective reduction.

The application discloses a ferrous sulfate high-temperature crystallization production device and a production method, which comprise a temperature adjusting tank, an energy-saving mechanism is arranged outside the temperature adjusting tank, the energy-saving mechanism comprises a heat pump and a water storage tank, the inside of the heat pump and the inside of the water storage tank are connected through two circulating pipes, water pipes are connected through both sides of the inside of the water storage tank, connecting pipes are connected through both sides of the inside of the heat pump, one end of the connecting pipe is connected with a spiral pipe through a flange, the spiral pipe is arranged on the outer surface of the temperature adjusting tank, and a condenser pipe is fixedly connected through the outer surface of the spiral pipe, and the application relates to the technical field of ferrous sulfate production devices, solves the problem that in the production process of the existing ferrous sulfate high-temperature crystallization production device, steam generated by flash evaporation and heat energy lost by concentrated raw material liquid cooling are directly lost in the external air, heat is wasted, and the energy-saving and environmental protection concept is not met.

The invention belongs to the technical field of titanium dioxide production waste resource utilization, and particularly relates to a method for synergistically preparing ammonium sulfate and white carbon black from sulfuric acid method titanium dioxide waste acid. According to the method, iron is pre-removed through precision filtration and low-temperature crystallization, most impurities and ferrous sulfate in the waste acid are removed, then the waste acid serves as a cheap acid source, white carbon black and ammonium sulfate are prepared, all-component utilization of the waste acid is achieved, sulfuric acid in the waste acid is used for preparing white carbon black and ammonium sulfate, iron ions are recycled into ferrous sulfate heptahydrate, the resource utilization rate is larger than or equal to 98%, and the cost is low. And the problem of waste acid discharge is thoroughly solved, and the fundamental transformation from tail end treatment to source recycling is realized. Moreover, the steps of pre-treatment and iron pre-removal ensure high whiteness and low impurity content of the white carbon black, and meet high-end application requirements. Meanwhile, the purity and color of the ammonium sulfate product are also ensured. And 800-1000 yuan benefits can be additionally created for each ton of waste acid, so that direct and considerable benefits are brought to titanium dioxide production enterprises.

This invention relates to a method and system for the combined processing of Bayer process red mud and low-grade bauxite. The method includes: separately detecting the aluminum and silicon content in the red mud and bauxite, mixing the red mud and bauxite according to the detection results to achieve an aluminum-to-silicon ratio greater than 1 in the resulting raw material, adding a calcination aid, and calcining to obtain clinker. The clinker undergoes multiple cycles of water leaching and primary desilication treatment until the aluminum-to-silicon ratio in the solution is greater than 300 and the vanadium content reaches 2 g / L, at which point deep desilication is performed. The deep desilication solution is then carbonated to extract aluminum. Ammonium salts are added to the resulting solution to further extract vanadium. The final solution is crystallized and used as a calcination aid. The water leaching residue from the water leaching treatment is acid-leached, aged, and hydrolyzed to polymerize, yielding calcium sulfate, silica gel, and a water purification agent, respectively. This invention effectively utilizes both major and rare elements, solving the problems of red mud accumulation and the ineffective utilization of low-grade bauxite.

The invention discloses a battery grade ferrous sulfate continuous cooling crystallization method and system based on a crystal form directing agent, and the method comprises the following steps: mixing a purified ferrous sulfate solution with a nanoscale CHA / MOR molecular sieve crystal form directing agent, feeding the mixture into a multi-stage continuous crystallization kettle, carrying out temperature control crystallization, and finally carrying out solid-liquid separation to obtain a product, the system correspondingly comprises a crystallization kettle, a crystal form guiding agent and a seed crystal adding unit which are connected in sequence, the crystal morphology is actively regulated and controlled by utilizing the specific crystal form guiding agent, and the high-tap-density columnar crystal is obtained; an electric field is arranged in a crystallization transition area, so that in-situ directional migration and deep removal of foreign ions are realized; a crystal form memory elimination module is integrated, impurity circulation is broken through rapid freezing-instantaneous heating, efficient and energy-saving deep purification is achieved, the problems that in battery-grade ferrous sulfate production, the crystal morphology is uncontrollable, the impurity content is high, the technological process is long, and energy consumption is large are synchronously solved, and the product is high in purity and good in physical performance; the method is especially suitable for preparing a lithium ion battery positive electrode material precursor.

The application relates to the technical field of sodium ion batteries, in particular to a sodium ferric sulfate positive electrode material and a preparation method and application thereof. The preparation method of the sodium ferric sulfate positive electrode material comprises the following steps: obtaining a carbon foam substrate; weighing raw materials according to the stoichiometric ratio of the sodium ferric sulfate positive electrode material and adding the raw materials into a solvent to obtain a mixed solution; depositing the mixed solution on the carbon foam substrate by using an electrostatic spray deposition method to obtain a precursor film; and performing sintering treatment on the precursor film to obtain the sodium ferric sulfate positive electrode material. The carbon foam is used as a substrate material, the electrostatic spray deposition is simultaneously performed to prepare a sodium ferric sulfate precursor, and then sintering treatment is performed to obtain the sodium ferric sulfate material, so that the discharge specific capacity, the rate performance and the cycle performance of the sodium ferric sulfate material are all significantly improved.

Aspects of the invention include a method of producing a cement material comprising a first reaction step in which a calcium-containing starting material is reacted with a first acid to produce a water-soluble first calcium salt, a second reaction step in which the water-soluble first calcium salt is reacted with a second acid to produce a solid second calcium salt, where the second acid is different from the first acid and the second calcium salt is different from the first calcium salt, and a heat-treating step in which the second calcium salt is heat-treated to produce a first cement material. Preferably, but not necessarily, during the second reaction step, the reaction between the first calcium salt and the second acid regenerates the first acid.

The invention provides a preparation method of ammonium ferrous sulfate, and relates to the technical field of inorganic salt preparation.The preparation method of the ammonium ferrous sulfate comprises the following steps that raw materials of iron and a sulfuric acid solution are taken and mixed for a reaction, and a ferrous sulfate solution is obtained; adding solid ammonium sulfate into the ferrous sulfate solution to obtain an ammonium ferrous sulfate solution; and taking the ammonium ferrous sulfate solution, filtering impurities, taking filtrate, and performing evaporative crystallization to obtain ammonium ferrous sulfate. Ferrous sulfate reacts with ammonium sulfate to form double salt ammonium ferrous sulfate, and since the electron configuration is affected by a ligand field, the electron configuration of ferrous iron in the double salt is not easy to oxidize due to the influence of the ligand field, and the ferrous iron is not easy to oxidize even if the ferrous iron is fully contacted with air in the filtering process; the method has the advantages that oxidation of ferrous ions is reduced, the impurity content is reduced, the product purity and the batch stability are improved, additional secondary purification treatment is not needed, and the technological process is simplified.

The invention belongs to the field of resource recovery treatment, and discloses a comprehensive recovery treatment method of cyanidation tailings, which comprises the following steps: mixing cyanidation tailings to be treated, an additive and concentrated sulfuric acid, and curing and roasting to obtain a cured product; wherein the additive is a combination of calcium chloride and ferric chloride in a mass ratio of (2: 1)-(4: 1); the mass ratio of the cyanidation tailings to the additive is 1: (0.1-0.3); the cured product is subjected to water leaching, and gold-rich residues and filtrate are obtained; the filtrate is purified, evaporated and concentrated, and ferric sulfate crystals are obtained. According to the method, the cyanidation tailings, the additive and the concentrated sulfuric acid are cured and roasted, and then water leaching, purification and evaporation concentration are performed, so that synergistic efficient recovery and high-value utilization of valuable resources in the cyanidation tailings can be realized, and the economic benefit is remarkable.

The application discloses a continuous iron dissolving method for preparing iron phosphate, and comprises the following steps: S1, acid solution is added into a dynamic tubular reactor for pre-washing, and the flow of the acid solution is calibrated, and iron powder is added into the dynamic tubular reactor according to a reducing parameter; S2, a displacement reaction occurs in the dynamic tubular reactor, and the dynamic tubular reactor is in a closed and slightly negative pressure environment; acid mist and by-product hydrogen overflowing from the dynamic tubular reactor are pumped into a gas-liquid separator, and then the hydrogen is pumped into a hydrogen storage tank; S3, the iron phosphate solution obtained through the reaction of the dynamic tubular reactor is filtered through a bag filter through the gas-liquid separator, and then the iron phosphate solution is sampled and analyzed to obtain a clear iron dissolving solution. The application can accurately control the addition amount of raw materials, so that the iron powder is fully reacted in the reactor without residual iron powder, and the continuous iron dissolving process is realized. The safety problem caused by the high hydrogen concentration in the environment due to hydrogen production in the iron dissolving process is effectively solved.

The invention discloses a method for separating and recycling iron in iron-containing waste residues, and relates to the technical field of industrial solid waste recycling. The method comprises the following steps: mixing and leaching the iron-containing waste residue and an acid solution, and filtering to obtain a leaching solution; adding phosphoric acid into the leachate, adjusting the pH value of the solution to 1.8-2.5, reacting, and filtering to obtain iron phosphate precipitate; washing the iron phosphate precipitate, dissolving the iron phosphate precipitate in a sulfuric acid solution, adding a reducing agent to reduce ferric iron into ferrous iron to obtain a reducing solution, separating out ferrous sulfate in the reducing solution by adopting an alcohol precipitation method or an ammonium sulfate crystallization method, and filtering to obtain a ferrous sulfate precipitate or ammonium ferrous sulfate crystal and a mother solution; dissolving the ferrous sulfate precipitate or the ammonium ferrous sulfate crystal in water, and removing impurities to obtain battery-grade ferrous sulfate or battery-grade ammonium ferrous sulfate; after evaporating and concentrating the mother liquor, obtaining a phosphoric acid solution through extraction or barium salt desulfurization. According to the method, iron in the iron-containing waste residues can be separated and recycled, and battery-grade ferrous sulfate or battery-grade ammonium ferrous sulfate can be obtained.

The invention discloses a method for preparing an iron salt water purifying agent by using iron-containing waste acid, which comprises the following steps: mixing the iron-containing waste acid with an additional acid solution to obtain an iron salt raw material; then the ferric salt raw material and oxygen are subjected to a continuous flow reaction, and a ferric salt water purifying agent is obtained; the mass fraction of hydrogen ions in the ferric salt raw material in terms of hydrogen chloride is 4.8-8.5%; in the continuous flow reaction, the conveying flow rate of the ferric salt raw material is 500-2000kg / h, and the ratio of the conveying flow rate of the ferric salt raw material to the conveying flow rate of oxygen is 1000: (10-20); the temperature of the continuous flow reaction is 100-165 DEG C, and the pressure of the continuous flow reaction is 1.25-2 MPa. According to the invention, oxygen is taken as an oxidizing agent, the mass fraction of hydrogen ions in the ferric salt raw material is controlled in a specific range, the conveying flow rate of the ferric salt raw material is controlled in a specific range, and the pressure of continuous flow reaction is controlled in a specific range, so that the prepared ferric salt water purifying agent is high in Fe < 3 + > ion content; the content of free acid is low, and the content of insoluble substances is low.