166results about "Phosphoric acid" patented technology

The invention discloses an ultra-aeration air flotation system and an implementation method thereof, and belongs to the technical field of wet-process phosphoric acid production, and the ultra-aeration air flotation system comprises a reaction tank, an inclined guide plate arranged on the inner wall of the reaction tank, a dish-shaped tank which is arranged at the bottom of the reaction tank and is annularly arranged around the center of the reaction tank, and a central island which is formed by protruding the inner ring part of the dish-shaped tank at the bottom of the reaction tank, the aeration mechanism is arranged on the central island and is communicated with the outside through a pipeline; the transmission mechanism is arranged above the reaction tank; the central transmission rod is connected with the output end of the transmission mechanism and is arranged along the axis of the reaction tank; the dynamic settler is arranged at the upper part in the reaction tank and is connected with the central transmission rod; and the overflow port is matched with the dynamic settler. The inclined guide plate, the dish-shaped aeration structure and the dynamic settler are integrally arranged in the reaction tank, so that the super-aeration uniformity, the foam separation capacity, the phosphoric acid purification and the liquid vortex intensity in the wet-process phosphoric acid production process are remarkably enhanced, and the reaction efficiency and the product quality are improved.

The present invention discloses a super-aeration flotation system and its implementation method, belonging to the technical field of wet-process phosphoric acid production. The system comprises a reaction tank, an inclined guide plate arranged on the inner wall of the reaction tank, a dished trough arranged at the bottom of the reaction tank and arranged in a ring shape around its center, a central island formed by a protrusion of the inner ring portion of the dished trough at the bottom of the reaction tank, an aeration mechanism arranged on the central island and connected to the outside through a pipeline, a transmission mechanism installed above the reaction tank, a central transmission rod arranged along the axis of the reaction tank and connected to the output end of the transmission mechanism, a dynamic settler arranged at an upper position in the reaction tank and connected to the central transmission rod, and an overflow port matched with the dynamic settler. By integrating the inclined guide plate, the dished aeration structure and the dynamic settler in the reaction tank, the present invention significantly enhances the super-aeration uniformity, foam separation ability, phosphoric acid purification and liquid vortex intensity in the wet-process phosphoric acid production process, thereby improving reaction efficiency and product quality.

This invention discloses a dynamic defoaming device for a stirring system, belonging to the technical field of wet-process phosphoric acid production equipment. It includes a reaction tank, a stirring shaft, stirring blades, a three-phase feeder, a liquid overflow port, an overflow depth adjuster, an interface foam separator, a secondary foam separator, and a foam overflow port. The overflow depth adjuster is located on the inner wall of the reaction tank, with its upper end connected to the liquid overflow port and its lower end adjustablely positioned in the middle of the reaction tank. The interface foam separator is located within the reaction tank and matches the material liquid level. The secondary foam separator is located in the upper part of the reaction tank and maintains a set interval from the interface foam separator, forming a static foam space. This invention achieves efficient and thorough foam removal and precise separation of liquid and solid materials, effectively improving the purity of phosphoric acid products, production efficiency, and equipment operational stability.

A process for purifying a phosphorus-containing source, comprising the following steps: a) At a temperature lower than 100°C for a duration lower than 180 minutes, reacting at least one phosphorus-containing source which comprises metallic trace elements and at least 5 wt.% and at most 50 wt.% of phosphorus expressed as P2O5 equivalent with at least one mineral acid leading to a digested suspension comprising said metallic trace elements in a liquid phase, and a solid phase mainly comprising phosphorus-containing compounds, wherein the reaction is performed at a molar ratio H+ / P2O5 comprised between 0.05 and 5, b) Separating said liquid phase from said digested suspension.

The invention discloses a phosphoric acid production process which comprises the following steps: S1, mixing phosphoric acid and phosphorite in a reactor for reaction, and filtering and washing reaction liquid to obtain monocalcium phosphate filtrate; s2, the monocalcium phosphate filtrate enters a bipolar membrane electrodialyzer, the bipolar membrane electrodialyzer is formed by sequentially arranging a cation exchange membrane, an anion exchange membrane and a bipolar membrane, and an acid chamber, a salt chamber and an alkali chamber are formed respectively; the monocalcium phosphate is converted into phosphoric acid and calcium hydroxide under the action of the electrodialyzer. According to the method, phosphoric acid with relatively high purity can be directly prepared, and phosphogypsum is not generated. Compared with the traditional wet-process phosphoric acid, the produced solid waste amount is sharply reduced and is about one tenth to one twentieth of that of the traditional wet-process phosphoric acid, and the phosphoric acid is rich in silicon, magnesium, iron and the like and can be used as a fertilizer additive.

The utility model relates to the technical field of phosphorite treatment, in particular to a device and system for preparing ammonium phosphate and byproduct nitrophosphate fertilizer by decomposing phosphorite with nitric acid. The device comprises an acidolysis tank, the acidolysis tank is connected to a first separator, the first separator is connected to a first crystallizer, the first crystallizer is connected to a second separator, the second separator is connected to a decalcification tank, the decalcification tank is connected to a denitration tank, and the denitration tank is connected to a second crystallizer. The denitration tank is respectively connected to the repulping tank and the purification equipment; the re-pulping tank is connected to a neutralizing tank, and the neutralizing tank is connected to a first concentrator; and the purification equipment is connected to the second concentrator. According to the device disclosed by the invention, the mother liquor generated by the acidolysis tank is deeply processed to prepare monoammonium phosphate and purified phosphoric acid, meanwhile, a byproduct white fertilizer can be processed into a phosphorus (potassium) nitrate fertilizer, and a byproduct white gypsum is obtained.

Provided are a surface treatment method, a sequencing method, and a kit for nucleic acid molecule extension. The surface treatment method comprises: contacting a phosphate compound with a surface bound with an oligonucleotide, wherein the phosphate compound comprises a compound having a structural formula represented by formula (1) and / or formula (2). With regard to the problem that bases are prone to random adsorption on the surface of the sequencing chip in the sequencing process, it has been unexpectedly discovered that compounds with a specific structure can compete with virtual terminator bases in the sequencing process for adsorption on the surface of the sequencing chip, thus reducing the random adsorption of bases on the surface of the sequencing chip, reducing the resultant sequencing error rate, and improving the sequencing throughput.

The present disclosure provides a method for producing calcium nitrate from calcium lactate. The method comprises: a) providing an aqueous calcium lactate solution; b) adding phosphoric acid to the aqueous calcium lactate solution, thereby producing a first composition comprising lactic acid and calcium phosphate; c) separating the calcium phosphate from the first composition, thereby obtaining an aqueous lactic acid solution and a second solid composition comprising calcium phosphate; d) reacting the second solid composition with nitric acid, thereby obtaining a third composition comprising phosphoric acid and calcium nitrate; and e) separating the calcium nitrate from the third composition, thereby obtaining an aqueous phosphoric acid solution and a solid calcium nitrate composition.

A method for production of pure phosphates comprises providing (S10) of a strip solution being an aqueous solution of one of monoammonium phosphate and monopotassium phosphate, loaded with stripped phosphate from a feed liquid comprising phosphoric acid contaminated by heavy metals and iron A base is added (S20) into the separated strip solution raising the pH to 2 – 5.5, forming of a heated solution and causing compounds comprising iron and phosphate to precipitate. A precipitant, precipitating heavy metals, is added (S30). Precipitated compounds comprising iron and phosphate and precipitated heavy metal compounds are separated (S40). The heated filtered solution is thereafter cooled off (S50) into a cooled solution, causing precipitation of phosphate compounds. The precipitated phosphate compounds are removed (S60) from the cooled solution. The cooled solution is recirculated (S70) for use as input strip solution in the stripping operation. A system for production of pure phosphates is also disclosed.

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 relates to a wet-process phosphoric acid production process for phosphorite all-element resource comprehensive utilization, and belongs to the field of phosphorus chemical industry production. The process comprises the following steps: decomposing phosphorite, a decomposition solution and a base solution to obtain a primary decomposition solution and primary decomposition slag; crystallizing the primary decomposition liquid to obtain ammonium dihydrogen phosphate crystals and crystallization mother liquor thereof; ammonium dihydrogen phosphate is directly sold as a product or transformed to produce high-quality phosphoric acid, and the obtained crystallization mother liquor is returned to be used for preparing a decomposition solution or a decomposition base solution; transforming the primary decomposition slag by ammonium bicarbonate to obtain an ammonium sulfate solution and a calcium carbonate filter cake; returning the ammonium sulfate solution for preparing decomposition liquid or comprehensively utilizing; transforming the calcium carbonate filter cake through ammonium chloride to obtain a mixed gas containing CO2 and NH3, a calcium chloride solution and insoluble filter residues; the calcium chloride solution further produces a calcium-containing compound. According to the process provided by the invention, the phosphogypsum can be consumed from the source, the consumption of sulfuric acid is low, the fluorine leaching rate is high, the comprehensive utilization rate of calcium resources is high, and the quality of phosphoric acid obtained through transformation is good.

The invention belongs to the field of solid waste utilization, and particularly provides a Ca2PO4Cl decomposition and resource utilization method, which comprises the following steps: dispersing Ca2PO4Cl in an alcohol solvent, and carrying out solvothermal modification treatment to obtain a modified material; carrying out protonation treatment on the modified material in a separation liquid containing an imgabs0 # auxiliary agent in a formula 1 # and hydrochloric acid, and decomposing to obtain a treatment product of phosphoric acid and calcium chloride; and separating to obtain calcium chloride and phosphoric acid. The method for decomposition and resource utilization of Ca2PO4Cl still belongs to the industry blank, and in order to fill the technical blank, the innovative research shows that Ca2PO4Cl is subjected to solvothermal modification transformation in alcohol in advance, and then ion exchange is performed in a hydrochloric acid solution containing a formula 1, so that decomposition of Ca2PO4Cl can be realized, and calcium chloride and phosphoric acid are formed.

The utility model discloses a device for stably conveying phosphoric acid to a production line by using waste heat of the production line, which is used for conveying 85% phosphoric acid in ammonium polyphosphate production and comprises a first phosphoric acid storage tank and a second phosphoric acid storage tank, the bottom of the first phosphoric acid storage tank is connected with a first acid discharge pipe, and the bottom of the second phosphoric acid storage tank is connected with a second acid discharge pipe. The device for stably conveying phosphoric acid to the production line by using the waste heat of the production line further comprises a constant-temperature hot water tank, a production line waste heat fluid pipeline and a phosphoric acid main pipe, the first acid discharge pipe and the second acid discharge pipe are respectively communicated with the phosphoric acid main pipe, and the production line waste heat fluid pipeline is connected with the constant-temperature hot water tank. A first hot water heating jacket is arranged outside the tank bottom of the first phosphoric acid storage tank, a second hot water heating jacket is arranged outside the tank bottom of the second phosphoric acid storage tank, the phosphoric acid conveying device further comprises a heat preservation water pipe and a heat preservation water return pipe, and a first pump is installed on the heat preservation water pipe; the heat preservation water pipe is communicated with the first hot water heating jacket, the second hot water heating jacket and the constant-temperature hot water tank, the heat preservation water return pipe is communicated with the first hot water heating jacket, the second hot water heating jacket and the constant-temperature hot water tank, a second pump is installed on the output section of the phosphoric acid main pipe, and an outlet of the second pump is connected with a production line use conveying pipe. The phosphoric acid conveying device can stably convey 85% phosphoric acid to a production line.

The invention relates to a process for obtaining phosphoric acid from phosphate-containing ash from waste incineration plants, in particular from sewage sludge ash from sewage sludge incineration plants. Pure phosphoric acid, especially purified phosphoric acid, is obtained in several steps. Calcium sulfate, which is used, for example, as a building material, and acidic metal salt solutions, which can be used again for precipitation in wastewater treatment plants, are also produced. In the improved process according to the invention, turbidity or precipitation occurring in the filtrates, supernatants, and eluates is reduced or removed in at least one turbidity separation step.

The disclosure relates to a continuous process for obtaining phosphoric acid and calcium sulphate dihydrate from apatite, and sulphuric acid using hydrochloric acid as an intermediate attacking agent, comprising the steps: Leaching (101) apatite (11) with an aqueous solution of hydrochloric acid (12,13) to solubilize phosphorus compounds contained in the apatite, thereby obtaining a solution (15) containing phosphate (H3PO4) and calcium chloride (CaCl2); extracting (103) said solution (15) with organic solvent (16), yielding an organic extract (17) loaded with phosphate ions, and an aqueous raffinate (21) containing calcium chloride and residual impurities; re-extracting the phosphate ions from the organic extract (17) with water (18), thus yielding an aqueous extract (19) of phosphoric acid, and an unloaded organic phase substantially free of phosphoric acid, reacting (107) the raffinate (21) containing calcium chloride with sulphuric acid (26) to cause precipitation of calcium ions in the raffinate as calcium sulphate dihydrate and to recover chloride ions in the raffinate in the form of hydrochloric acid (12), wherein the reaction of the raffinate (21) containing calcium chloride with sulphuric acid (26) involves intermittent agitation of the raffinate, filtering off (108) precipitated calcium sulphate dihydrate (27) from the previous step (107) and washing it with water, recycling (112) the recovered hydrochloric acid (12) to the step (101) of the leaching apatite.

Provided is a method for producing a phosphate capable of easily producing a target phosphate. This method for producing a phosphate includes: an acid leaching step (S1) of leaching a component contained in a starting material containing phosphorus into an acid to obtain a phosphorus-containing liquid; and a precipitation formation step (S2) of adding an alkali to the phosphorus-containing liquid to obtain a precipitate containing a phosphate, wherein in the precipitation formation step (S2), the pH of the phosphorus-containing liquid is adjusted according to the temperature of the phosphorus-containing liquid.

The application discloses a kind of phosphoric acid extraction semi-water-two water alternate crystallization system and method, belong to the technical field of wet-process phosphoric acid production, the system is by the reaction tank unit of series connection and semi-water and two water reaction tank alternate arrangement, with the sulfuric acid dilution mixed heat exchanger group connected with reaction tank, simple heat exchanger group is arranged between tank to realize heat transfer.Construction.The method includes: material is temperature-adjusted after passing through sulfuric acid dilution mixed heat exchanger, in turn into the reaction tank sequence of alternate arrangement, heat circulation is carried out in adjacent tank by simple heat exchanger, under the control of PLC in 75~85 DEG C and 88~95 DEG C interval, realize the alternate crystallization of semi-water-two water calcium sulfate.The application replaces traditional flash evaporation external discharge with heat internal circulation between tank, solves the technical problems of high steam energy consumption, low phosphorus recovery rate, insufficient phosphoric acid concentration and high upgrading cost of stock device in traditional process, and has the comprehensive advantages of energy saving, yield, low-cost transformation and phosphogypsum resource.

The invention discloses a method for treating industrial waste gas through co-production with phosphorus chemical production, and belongs to the technical field of air pollution prevention and control. The method comprises the following steps: (1) crushing and grinding phosphorite, and then mixing the ground phosphorite with water to prepare phosphorite slurry; (2) carrying out countercurrent contact on the phosphoric ore pulp obtained in the step (1) and smelting flue gas, carrying out smelting flue gas purification treatment, and collecting slurry I after purification treatment; (3) adding sulfuric acid into the slurry I obtained in the step (2), and stirring until the concentration of phosphoric acid in the slurry I reaches 5% or above according to P2O5, so as to obtain slurry II; and (4) conveying the slurry II obtained in the step (3) to a wet-process phosphoric acid production process for recycling to produce phosphoric acid. According to the invention, industrial waste gas purification treatment is carried out through co-production with phosphorus chemical industry production, and the resource utilization rate of low-grade phosphorite and other wastes can be improved, so that secondary pollution is reduced, and good purification treatment of waste gas with relatively complex pollutants is realized on the basis of low cost.

The invention relates to the field of phosphoric acid production, and particularly discloses an improved nitric acid method crude phosphoric acid production process and a denitration concentration system. The production process comprises the following steps: decomposing phosphorite with dilute nitric acid, freezing and crystallizing the obtained acidolysis solution, filtering, and adding concentrated sulfuric acid to obtain a mixed acid solution containing phosphoric acid and nitric acid; and introducing the mixed acid liquid into a first-effect evaporator and a second-effect evaporator for double-effect evaporation, and distilling in a rectifying tower to obtain a crude phosphoric acid product. According to the application, mixed acid is subjected to denitration concentration by adopting a downstream double-effect evaporation technology, by virtue of a pressure-temperature double-gradient design and in combination with a rectifying tower, staged denitration is realized by utilizing the pressure dependence of the volatility of nitric acid, and primary denitration and energy supply are realized by adopting a high-pressure and high-temperature evaporation section as a first-effect evaporation section; the second-effect evaporation is a vacuum low-temperature evaporation section, deep denitration and acid enrichment are achieved, and the concentration of nitric acid enriched in the low-temperature section reaches 55 wt%. The concentration of phosphoric acid in the finally obtained product is more than or equal to 75wt%, and the residual nitric acid is less than or equal to 0.5

The invention discloses a dechlorination method of a wet-process phosphoric acid process, and belongs to the technical field of dechlorination of wet-process phosphoric acid. The method comprises the following steps: adding ground phosphorite into a reaction tank A, carrying out decomposition reaction on the phosphorite and high-temperature slurry to obtain slurry a, pumping the slurry a into a reaction tank B, adding concentrated sulfuric acid and a sodium persulfate solution, activating sodium persulfate in the inherent high temperature, strong acid and Fe2 environment, carrying out oxidation dechlorination reaction, and carrying out solid-liquid separation to obtain low-chlorine phosphoric acid and phosphogypsum; finally, the reaction tank B is connected with a tail gas washing system, water is used for circulating washing, then alkali liquor is used for countercurrent washing, and the pollution discharge standard is met. The oxidation dechlorination process is integrated in the wet-process phosphoric acid production process for the first time, chloride ions are efficiently oxidized into chlorine to be removed by utilizing the strong oxidizing property of sodium persulfate, the dechlorination rate can reach 95% or above, the chlorine content in phosphoric acid is remarkably reduced, equipment corrosion is relieved, the product quality is improved, and the method is simple in process, low in energy consumption, low in cost, green, environmentally friendly and suitable for industrial production. The method is suitable for industrial application.

The utility model discloses a kiln for extracting phosphorus steam from phosphate ore, which comprises a kiln body, and a preheating section, a heating section and a cooling section are sequentially arranged in the kiln body along the length direction; the rails are symmetrically arranged in the kiln body and extend in the length direction of the kiln body. At least one of the preheating section and the cooling section is provided with a phosphorus discharge port, and the phosphorus discharge port is communicated with an external phosphorus steam collecting device; in the phosphorus steam preparation process, the materials are in a static state, the phosphorus steam purity in the reaction process is high, smoke and impurities do not exist, safety and environmental protection are achieved, the operation cost is low, the automation degree is high, and trolley running, temperature control and pressure control can be automatically controlled through a computer in a central control room in the whole process.

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 utility model provides a high-pollution industrial waste discharge treatment system, which is characterized in that a waste discharge treatment device of high-pollution industrial manufacturing equipment is provided with a green energy waste gas treater, and the high-pollution industrial manufacturing equipment comprises a fluid discharge guide system for generating discharge guide airflow; wherein the green energy waste gas treater guides waste gas discharged by high-pollution industrial manufacturing equipment into a suction end face of the green energy waste gas treater by discharging guide airflow, and the waste gas is subjected to clean reaction treatment through the green energy waste gas treater, so that the waste gas is separated into gas-phase fluid and liquid-phase fluid through the green energy waste gas treater; the gas-phase fluid is discharged from the exhaust end face of the green-energy waste gas treater, and the liquid-phase fluid is discharged from the liquid outlet of the green-energy waste gas treater, so that the demisting efficiency of waste discharge treatment of the high-pollution industrial manufacturing equipment can be effectively improved.

A method for producing pure phosphate comprises providing (S10) a reextraction solution carrying a reextracted phosphate from a feed liquid comprising phosphoric acid contaminated with a heavy metal and iron, the reextraction solution being an aqueous solution of one of monoammonium phosphate and monopotassium phosphate. A base is added (S20) to the separated reextraction solution, raising the pH to 2-5.5, forming a heated solution and causing precipitation of a compound comprising iron and phosphate. And adding (S30) a precipitating agent for precipitating heavy metals. Separating (S40) the precipitated compound comprising iron and phosphate and the precipitated heavy metal compound. Thereafter, the heated filtered solution is cooled (S50) into a cooled solution, causing precipitation of the phosphate compound. The precipitated phosphate compound is removed from the cooled solution (S60). The cooled solution is recycled (S70) for use as an input back extraction solution in the back extraction operation. A system for producing pure phosphates is also disclosed.

Provided herein are systems and methods for producing nitrophosphates and mineralized carbon. Advantageously, the systems and methods are capable of sequestering carbon from the atmosphere. The systems generally include a first reactor for producing nitric acid; a mixer for mixing the nitric acid produced in the first reactor with a phosphate source, thereby producing nitro-phosphoric acid; and a second reactor for producing a solution comprising nitrophosphates and mineralized carbon, wherein the second reactor is operable to receive: the nitro-phosphoric acid from the mixer, ammonia, water, and carbon dioxide.

The production method comprises the following steps: S1, feeding industrial yellow phosphorus into a primary filter for primary filtration, washing, and feeding the industrial yellow phosphorus into a secondary filter for secondary filtration to obtain high-purity yellow phosphorus; s2, the high-purity yellow phosphorus is fed into a combustion tower for oxidative combustion to generate phosphorus pentoxide, ultrapure water is introduced for a hydration reaction to generate a phosphoric acid solution, the phosphoric acid solution is fed into a third-stage filter for third filtration, and arsenic-containing electronic-grade phosphoric acid is obtained; s3, sending the arsenic-containing electronic-grade phosphoric acid into an arsenic removal tank for reaction, removing arsenic salt generated in the reaction, and further removing the arsenic salt through an ultrafiltration system to obtain arsenic-removed electronic-grade phosphoric acid; and S4, blending the arsenic-removed electronic-grade phosphoric acid with ultrapure water, and after blending, feeding into a four-stage filter for fourth filtering to obtain the electronic-grade phosphoric acid. The process can effectively remove impurities of front-end raw materials, middle-end reaction liquid and rear-end products, and the yield of phosphoric acid reaches 95% or above.

Provided are a surface treatment method, a sequencing method, and a kit for nucleic acid molecule extension. The surface treatment method comprises: contacting a phosphate compound with a surface bound with an oligonucleotide, wherein the phosphate compound comprises a compound having a structural formula represented by formula (1) and / or formula (2). With regard to the problem that bases are prone to random adsorption on the surface of the sequencing chip in the sequencing process, it has been unexpectedly discovered that compounds with a specific structure can compete with virtual terminator bases in the sequencing process for adsorption on the surface of the sequencing chip, thus reducing the random adsorption of bases on the surface of the sequencing chip, reducing the resultant sequencing error rate, and improving the sequencing throughput. o

The utility model relates to the technical field of phosphoric acid production, in particular to a phosphoric acid graded production device which comprises a U-shaped support, a plurality of first installation openings which are distributed at equal intervals in the left-right direction are formed in the top of the U-shaped support, a reaction tank is installed on each first installation opening, and an electric heating plate is arranged between the outer wall and the inner wall of each reaction tank. A temperature sensor and a PH sensor are arranged on the inner wall of each reaction tank, the tops of the multiple reaction tanks are jointly connected with a top plate, and a plurality of feeding pipes are arranged at the top of the top plate. According to the phosphoric acid graded production device, the plurality of reaction tanks are respectively filled with crushed phosphate ores with different iron contents and a catalyst with the same content, so that phosphoric acid with different iron contents is obtained, multi-stage phosphoric acid production is realized, the interior of the reaction tanks is heated by the electric heating plates, and the catalyst and the crushed phosphate ores react favorably at a proper temperature; the temperature sensor and the PH sensor are used for detecting the temperature and PH value in the reaction tank, and it is ensured that the catalyst and the crushed phosphate ore react at the proper temperature and PH value.

The present invention relates to a method for combined recovery of phosphate and nitrogen from sewage sludge. The core objective of the present invention is to recover phosphorus from sewage sludge ash and convert phosphorus into NP fertilizer diammonium phosphate using steam from sewage sludge drying and nitrogen from liquid manure.

The invention relates to a safe and environment-friendly treatment method for residues in a tail gas pipeline of a lithium hexafluorophosphate drying process, which comprises the following steps: connecting a tail gas buffer tank in series in the tail gas pipeline of the lithium hexafluorophosphate drying process, and collecting waste materials formed by sedimentation from the tail gas buffer tank; the waste material is treated by the following steps: 1) adding ultrapure water and the lithium hexafluorophosphate waste material into a hydrolysis kettle, hydrolyzing, and extracting hydrofluoric acid through negative pressure azeotropy; 2) centrifuging; centrifugally collecting filtrate as phosphoric acid, and washing a filter cake until effluent is neutral to form crude lithium fluoride; 3) adding ultrapure water and concentrated hydrochloric acid into the crude lithium fluoride; after stirring for 0.5-1 hour, centrifuging to remove iron ions, washing a filter cake with ultrapure water until effluent is neutral, and discharging the filter cake to obtain wet lithium fluoride; and 4) drying the wet lithium fluoride until the moisture is qualified to obtain the lithium fluoride for lithium hexafluorophosphate production.According to the method, the pipeline maintenance cost is reduced, meanwhile, the lithium fluoride and byproducts of hydrofluoric acid and phosphoric acid are recovered from the waste material formed by collection, and the method is environment-friendly and energy-saving.