CN108313996B - Method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder - Google Patents
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- CN108313996B CN108313996B CN201810268409.XA CN201810268409A CN108313996B CN 108313996 B CN108313996 B CN 108313996B CN 201810268409 A CN201810268409 A CN 201810268409A CN 108313996 B CN108313996 B CN 108313996B
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- C01B25/16—Oxyacids of phosphorus; Salts thereof
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- C01B25/375—Phosphates of heavy metals of iron
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Abstract
A method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder comprises the following steps: feeding washing water containing hydrochloric acid in the iron phosphate production into an electrolytic cell to obtain chlorine; introducing chlorine into the yellow phosphorus water, and absorbing the chlorine by the yellow phosphorus water to obtain a mixture of phosphoric acid and hydrochloric acid; reacting a mixture of phosphoric acid and hydrochloric acid with the sulfuric acid cinder to obtain crude iron phosphate; according to the invention, after hydrochloric acid in primary washing water is subjected to electrolytic reaction, chloride ions generate chlorine, the chlorine reacts with yellow phosphorus water to generate a mixture of phosphoric acid and hydrochloric acid, the mixture of phosphoric acid and hydrochloric acid and sulfuric acid cinder generate crude iron phosphate, so that the sulfuric acid cinder is changed into valuable, the discharge of chloride ions is avoided from polluting the environment, cations are combined with hydroxide radicals to form precipitates to be discharged, the concentration of the cations is prevented from being continuously increased, the primary washing water subjected to electrolytic treatment can be recycled, the zero emission of the washing water is realized, meanwhile, the hydrochloric acid in the process is recycled, and the zero emission of the chloride ions is realized.
Description
Technical Field
The invention relates to the technical field of iron phosphate preparation, in particular to a method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder.
Background
The iron phosphate can be used as an iron source for preparing the lithium iron phosphate serving as the cathode material of the lithium ion battery, but the cost is high, only the iron phosphate occupies about half of the cost of the raw materials, the cost of the iron phosphate must be greatly reduced, and the market demand is met with high cost performance. The sulfuric acid cinder is the residue discharged after roasting pyrite to extract sulfur. Iron is the main available component in the clinker. At present, the comprehensive utilization of the sulfuric acid cinder is not ideal, and most of the sulfuric acid cinder is subjected to landfill treatment except for a small part of the sulfuric acid cinder used as iron making and building materials, so that the waste of resources and the environmental pollution are caused. The sulfuric acid cinder is used as a raw material for preparing the iron phosphate, and no report is found. The iron phosphate is required to be washed in the production process, the washing water contains low-concentration hydrochloric acid and chloride salt, if the washing water is not treated, the washing water cannot be recycled, and the hydrochloric acid and the chloride salt have low concentration, the washing water is difficult to treat by a conventional method, such as a neutralization replacement method, that is, a large amount of lime is adopted to perform a neutralization reaction with waste hydrochloric acid. The hydrochloric acid in the wastewater is treated by the method, the treatment cost is high, the recovery value is low, a large amount of wastewater is generated, the environment is polluted, the direct discharge not only causes resource waste, but also causes certain influence on the environment, particularly, the pollution of chloride ions to the environment is prominent, the iron phosphate contains a certain amount of free water and crystal water, the common treatment method comprises the steps of firstly adopting flash evaporation drying and then baking by an electric furnace, and the method has low production speed and high baking power consumption.
Disclosure of Invention
In view of the above, there is a need to provide a method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder, which can utilize sulfuric acid cinder to prepare iron phosphate, effectively recycle hydrochloric acid and washing water in iron phosphate washing water, satisfy zero emission of pollutants, especially zero emission of chloride ions, and roast iron phosphate, which is energy-saving and fast.
A method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder comprises the following steps: the method comprises the following steps: reacting the sulfuric acid cinder with secondary phosphoric acid to obtain a crude product of iron phosphate, wherein the mass percentage concentration of the secondary phosphoric acid is 20-80%;
step two: dissolving the crude iron phosphate with second hydrochloric acid, and filtering to obtain a clear liquid and filter residue, wherein the mass percentage concentration of the second hydrochloric acid is 20-30%;
step three: distilling the clear liquid to obtain a gaseous hydrogen chloride and iron phosphate crystallization product;
step four: condensing gaseous hydrogen chloride to obtain fourth hydrochloric acid, rectifying the fourth hydrochloric acid to obtain second hydrochloric acid, and returning the second hydrochloric acid obtained in the step II to dissolve crude iron phosphate, wherein the mass percentage concentration of the fourth hydrochloric acid is less than 5%;
step five: washing the iron phosphate crystal product with secondary washing water to obtain refined iron phosphate and primary washing water, wherein the primary washing water is washing water containing 1-5% by mass of first hydrochloric acid, the primary washing water also contains chloride, hydroxide corresponding to cations of the chloride is insoluble in water, and the secondary washing water is the primary washing water without chloride;
step six: feeding the primary washing water into an electrolysis device for electrolysis to obtain chlorine, hydrogen, hydroxide precipitates and secondary washing water, discharging the hydrogen from a hydrogen discharge port, discharging the hydroxide precipitates from an electrolysis bath, returning the secondary washing water to the fifth step for washing the iron phosphate crystal product, and converting the secondary washing water into the primary washing water again;
step seven: introducing the chlorine into yellow phosphorus water, and absorbing the chlorine by the yellow phosphorus water to obtain a mixture of first phosphoric acid and third hydrochloric acid;
step eight: returning the mixture of the first phosphoric acid and the third hydrochloric acid to the step one to react with the sulfuric acid cinder;
step nine: feeding the refined ferric phosphate obtained in the fifth step into a drying and calcining device for calcining to obtain anhydrous ferric phosphate, wherein the drying and calcining device comprises a direct-fired hot-blast stove, a dynamic calcining tower, a first discharging cyclone device, a transfer fan, a rotary flash dryer, a first reel, a second discharging cyclone device, a second reel, a bag-type dust remover and an induced draft fan, an air outlet of the direct-fired hot-blast stove is communicated with an air inlet of the dynamic calcining tower to provide heat energy for the dynamic calcining tower, a discharge outlet at the top of the dynamic calcining tower is communicated with a feed inlet of the first discharging cyclone device, an anhydrous ferric phosphate outlet is arranged at the bottom of the first discharging cyclone device, an air outlet at the top of the first discharging cyclone device is communicated with an air inlet of the transfer fan, an air outlet of the transfer fan is communicated with an air inlet of the rotary flash dryer so that high-temperature gas flowing out of the dynamic calcining tower is sent into the rotary flash, the rotary flash evaporation dryer is characterized in that heat energy is provided for the rotary flash evaporation dryer, a feed inlet of the rotary flash evaporation dryer is connected with a first reel, refined iron phosphate to be dried is sent into the rotary flash evaporation dryer through the first reel, a discharge outlet at the top of the rotary flash evaporation dryer is communicated with a feed inlet of a second discharging cyclone device, an iron phosphate dihydrate outlet is formed in the bottom of the second discharging cyclone device and communicated with a feed inlet of a dynamic calcining tower through the second reel, the iron phosphate dihydrate outlet is sent into the dynamic calcining tower to be calcined, an air outlet of the second discharging cyclone device is communicated with an inlet of a bag-type dust collector, and an outlet of the bag-type dust collector is communicated with an induced draft fan.
In the invention, after hydrochloric acid, phosphorus chloride, magnesium chloride and calcium chloride in primary washing water are subjected to electrolytic reaction, chlorine is generated by chloride ions, the chlorine reacts with yellow phosphorus water to generate a mixture of first phosphoric acid and third hydrochloric acid, the mixture of the first phosphoric acid and the third hydrochloric acid and sulfuric acid cinder generate crude iron phosphate, so that the sulfuric acid cinder is changed into valuable through recycling of the chloride ions, the environment pollution caused by the discharge of the chloride ions is avoided, cations are combined with hydroxyl to form precipitates to be discharged, the concentration of the cations is prevented from being increased continuously, the primary washing water subjected to electrolytic treatment can be recycled, the zero emission of the washing water is realized, the hydrochloric acid in the technical process is subjected to dissolving, filtering, distilling, condensing and rectifying treatment, the recycling is realized, the zero emission of the chloride ions is realized, a drying and calcining device is adopted for dynamic calcining, the discharged gas of a dynamic calcining tower is used for heating a rotary flash dryer, the waste heat is recycled, so that more energy is saved; the ferric phosphate dried by the rotary flash dryer returns to the dynamic calcining tower for roasting, thereby ensuring the rapid production.
Drawings
Fig. 1 is a flow chart of a method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder.
Fig. 2 is a schematic structural diagram of the evaporative condenser.
Fig. 3 is a schematic view of the structure of the boiling wall.
Fig. 4 is a schematic structural view of the condensation duct in a front view direction.
Fig. 5 is a schematic structural diagram of the condensing duct viewed from the right.
FIG. 6 is a schematic structural view of the drying and calcining apparatus in a plan view.
FIG. 7 is a schematic structural view of the direction of the drying and calcining device A.
FIG. 8 is a schematic structural view of the drying and calcining apparatus in the B direction.
In the figure: the device comprises an evaporation pan 10, a water inlet pipeline 11, a first electromagnetic valve 111, a water outlet pipeline 12, a second electromagnetic valve 121, a condensation pipeline 13, a condensation part 131, a baffle plate 1311, a liquid level controller 14, a boiling wall 15, a heating furnace 20, a combustion chamber 21, a hydrogen pipeline 22, a water discharge pipeline 23, a combustion-supporting gas pipeline 24, a drying and calcining device 30, a direct-fired hot blast stove 31, a dynamic calcining tower 32, a first discharging cyclone device 33, a transfer fan 34, a rotary flash drying machine 35, a first reel 36, a second discharging cyclone device 37, a second reel 38, a bag-type dust collector 39 and a draught fan 310.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
Referring to fig. 1, an embodiment of the present invention provides a method for preparing battery-grade anhydrous iron phosphate from sulfuric acid cinder, including the following steps:
step S300: reacting the sulfuric acid cinder with secondary phosphoric acid to obtain a crude product of iron phosphate, wherein the mass percentage concentration of the secondary phosphoric acid is 20-80%;
step S301: dissolving the crude iron phosphate with second hydrochloric acid, and filtering to obtain a clear liquid and filter residue, wherein the mass percentage concentration of the second hydrochloric acid is 20-30%;
step S302: distilling the clear liquid to obtain a gaseous hydrogen chloride and iron phosphate crystallization product;
step S303: condensing gaseous hydrogen chloride to obtain fourth hydrochloric acid, rectifying the fourth hydrochloric acid to obtain second hydrochloric acid, and returning the second hydrochloric acid obtained in the step to the step S301 to dissolve crude iron phosphate, wherein the mass percentage concentration of the fourth hydrochloric acid is less than 5%;
step S304: washing the iron phosphate crystal product with secondary washing water to obtain refined iron phosphate and primary washing water, wherein the primary washing water is washing water containing 1-5% by mass of first hydrochloric acid, the primary washing water also contains chloride, hydroxide corresponding to cations of the chloride is insoluble in water, and the secondary washing water is the primary washing water without chloride;
step S305: feeding the primary washing water into an electrolysis device for electrolysis to obtain chlorine, hydrogen, hydroxide precipitates and secondary washing water, discharging the hydrogen from a hydrogen discharge port, discharging the hydroxide precipitates from an electrolysis bath, returning the secondary washing water to the step S304 for washing the iron phosphate crystallization product, and converting the secondary washing water into the primary washing water again, wherein the secondary washing water is the primary washing water for removing chlorides;
step S306: introducing the chlorine into yellow phosphorus water, and absorbing the chlorine by the yellow phosphorus water to obtain a mixture of first phosphoric acid and third hydrochloric acid;
step S307: returning the mixture of the first phosphoric acid and the third hydrochloric acid to the step S300 for reacting with the sulfuric acid cinder;
step S308: feeding the refined iron phosphate obtained in the step S304 into a drying and calcining device 30 for calcining to obtain anhydrous iron phosphate, wherein the drying and calcining device 30 comprises a direct-fired hot blast stove 31, a dynamic calcining tower 32, a first discharging cyclone device 33, a transfer fan 34, a rotary flash dryer 35, a first reel 36, a second discharging cyclone device 37, a second reel 38, a bag-type dust remover 39 and an induced draft fan 310, an air outlet of the direct-fired hot blast stove 31 is communicated with an air inlet of the dynamic calcining tower 32 to provide heat energy for the dynamic calcining tower 32, a discharge hole at the top of the dynamic calcining tower 32 is communicated with a feed inlet of the first discharging cyclone device 33, an anhydrous iron phosphate outlet is arranged at the bottom of the first discharging cyclone device 33, an air outlet at the top of the first discharging cyclone device 33 is communicated with an air inlet of the transfer fan 34, and an air outlet of the transfer fan 34 is communicated with an air inlet, so that high-temperature gas flowing out of the dynamic calcining tower 32 is sent into the spin flash dryer 35 through the transfer fan 34 to provide heat energy for the spin flash dryer 35, a feed inlet of the spin flash dryer 35 is connected with the first twisting wheel 36, refined iron phosphate to be dried is sent into the spin flash dryer 35 through the first twisting wheel 36, a discharge outlet at the top of the spin flash dryer 35 is communicated with a feed inlet of the second discharging cyclone device 37, an iron phosphate dihydrate outlet is arranged at the bottom of the second discharging cyclone device 37, the iron phosphate dihydrate outlet is communicated with the feed inlet of the dynamic calcining tower 32 through the second twisting wheel 38 to send the iron phosphate dihydrate into the dynamic calcining tower 32 for calcination, an air outlet of the second discharging cyclone device 37 is communicated with an inlet of the cloth bag 39, and an outlet of the cloth bag dust remover 39 is communicated with the induced draft fan 310;
the specific process of roasting the refined iron phosphate by the drying and calcining device 30 is as follows: and (3) sending the refined ferric phosphate into a rotary flash evaporation dryer 35 through a first reel 36 for drying to obtain ferric phosphate dihydrate, wherein the ferric phosphate dihydrate flows out of a second discharging cyclone device 37, then is sent into a dynamic calcining tower 32 for calcining through a second reel 38, and then flows out of a first discharging cyclone device 33 to obtain the anhydrous ferric phosphate.
In FIG. 1, the first reaction refers to the reaction of chlorine and yellow phosphorus water, and the second reaction refers to the reaction of phosphoric acid and sulfuric acid cinder.
The refined iron phosphate obtained in the step S304 is dynamically calcined by the drying and calcining device 30, and the gas discharged from the dynamic calcining tower 32 is used for heating the spin flash dryer 35, so that waste heat recovery is realized, and energy is saved; the iron phosphate dried by the rotary flash dryer 35 is returned to the dynamic calcining tower 32 for calcining, thereby ensuring the rapid production.
In the invention, after hydrochloric acid, phosphorus chloride, magnesium chloride and calcium chloride in primary washing water are subjected to electrolytic reaction, chlorine is generated by chloride ions, the chlorine reacts with yellow phosphorus water to generate a mixture of first phosphoric acid and third hydrochloric acid, the mixture of the first phosphoric acid and the third hydrochloric acid and sulfuric acid cinder generate crude iron phosphate, so that the sulfuric acid cinder is changed into valuable through recycling of the chloride ions, the discharge of the chloride ions is avoided from polluting the environment, cations are combined with hydroxide radicals to form precipitates to be discharged, the concentration of the cations is prevented from being increased continuously, the primary washing water subjected to electrolytic treatment can be recycled, the zero emission of the washing water is realized, the hydrochloric acid in the technical process is subjected to dissolving, filtering, distilling, condensing and rectifying treatment, the recycling is realized, the zero emission of the chloride ions is realized, a drying and calcining device 30 is adopted for dynamic calcination, and the gas discharged by a dynamic calcining tower 32 is used for heating a rotary flash dryer 35, the waste heat is recycled, so that more energy is saved; the iron phosphate dried by the rotary flash dryer 35 is returned to the dynamic calcining tower 32 for calcining, thereby ensuring the rapid production.
Referring to fig. 1, further, the primary washing water in step 304 is subjected to a pretreatment step before electrolysis in step 305, wherein the pretreatment step is to pass the primary washing water through an evaporative condenser to concentrate the washing water with a mass percentage concentration of 1-5%, and the evaporative condenser is heated by using the hydrogen discharged in step 305.
In the embodiment, the hydrogen generated by the electrolytic reaction is used for evaporation and concentration of primary washing, so that the water electrolysis efficiency of the primary washing is improved, the electrolysis energy consumption is reduced, and meanwhile, the hydrogen emission is prevented from polluting the environment, and the energy waste is also avoided.
Referring to fig. 2, further, the evaporative condenser includes an evaporation pan 10, a heating furnace 20, a hydrogen pipeline 22, a drainage pipeline 23, and a combustion-supporting gas pipeline 24 are installed on the heating furnace 20, a water inlet pipeline 11, a water outlet pipeline 12, a condensation pipeline 13, and a liquid level controller 14 are installed on the evaporation pan 10, the evaporation pan 10 passes through a circular hole on the top wall of the heating furnace 20 and is nested in the heating furnace 20, an outer circumferential wall of an upper portion of the evaporation pan 10 is fixed and hermetically connected with an inner circumferential wall of the circular hole on the top wall of the heating furnace 20, one end of the hydrogen pipeline 22 is communicated with the bottom of a combustion chamber 21 of the heating furnace 20, the other end of the hydrogen pipeline 22 is communicated with a hydrogen discharge port of an electrolysis device, a drainage pipeline 23 is communicated with the bottom of the combustion chamber 21 of the heating furnace 20 to discharge water generated after the combustion of hydrogen, the bottom of the combustion, the upper part of the evaporative condenser is connected with a water inlet pipeline 11 to lead primary washing water to be pretreated into the evaporative condenser, a first electromagnetic valve 111 is arranged on the water inlet pipeline 11, the lower part of the evaporative condenser is connected with a water outlet pipeline 12 to lead the primary washing water after evaporation concentration into an electrolytic bath, a second electromagnetic valve 121 is arranged on the water outlet pipeline 12, after the water in the evaporative condenser is evaporated, water vapor forms condensed water at the top of the evaporative condenser, the condensed water is conveyed to a using point from a water outlet at the top of the evaporative condenser through a condensing pipeline 13 to wash an iron phosphate crystallization product, a liquid level controller 14 is arranged in the evaporative condenser, the liquid level controller 14 is electrically connected with a control module, the control module is electrically connected with the first electromagnetic valve 111 and the second electromagnetic valve 121, when the water level in the evaporative condenser is at a low water level, the liquid level controller 14 sends a low, the controller module controls the first electromagnetic valve 111 to be opened and the second electromagnetic valve 121 to be closed, when the water level in the evaporative condenser is at a high water level, the liquid level controller 14 sends a signal that the water level is high to the control module, and the control module controls the first electromagnetic valve 111 to be closed and the second electromagnetic valve 121 to be opened.
In this embodiment, the liquid level controller 14 controls the first electromagnetic valve 111 to close, and the second electromagnetic valve 121 to intermittently open or close, so as to control the liquid level of the primary washing water in the evaporative condenser, thereby indirectly controlling the mass percentage concentration of the hydrochloric acid in the pretreated primary washing water, so as to intermittently provide the primary washing water containing the hydrochloric acid required by the specified mass percentage concentration for the electrolysis apparatus.
Referring to fig. 2 and 3, the evaporative condenser has a boiling wall 15 contacting the raw water therein for heating the raw water, and fine protrusions are densely distributed on the side of the boiling wall 15 contacting the raw water, and the free ends of the protrusions are disposed as tips.
In this embodiment, the evaporative condenser is in contact with water, and the part for heating the water is provided as the boiling wall 15, on the one hand, the evaporation area is increased by the densely arranged fine protrusions, and on the other hand, the free ends of the protrusions are provided as tips to provide growth nuclei for bubble production, thereby promoting the evaporation of the water.
Referring to fig. 2, 4 and 5, further, the cross section of the condensing duct 13 is square, a plurality of condensing parts 131 are uniformly inserted into the condensing duct 13 along the length direction thereof at intervals, the condensing parts 131 include two baffle plates 1311, the two baffle plates 1311 are arranged in a reverse inclined manner, and each baffle plate 1311 is trapezoidal and perpendicular to the inner side wall of the exhaust duct.
The baffling board 1311 adjusts the condition that flows of vapor in the condensation pipe 13, after the baffling board 1311 was touched to vapor, a small part of comdenstion water flowed down along baffling board 1311, a plurality of baffling boards 1311 have increased the heat transfer area of vapor simultaneously, the condensation of vapor has been accelerated, behind the condensate film on the baffling board 1311 to certain thickness, gather in condensation pipe 13 bottom along baffling board 1311 under the effect of gravity and air current, flow to the point of use again along condensation pipe 13 bottom, for washing iron phosphate crystallization product, the vapor condensation effect has effectively been accelerated, this condensation pipe 13 neither additionally increases equipment structure, again can make full use of the space in the pipeline of existing equipment, and reached the water vapor condensation effect with higher speed, the structure is simple and easy, and practical.
Further, in the step S305, the electrolysis process of the primary washing water includes passing the pretreated primary washing water through a cation membrane electrolytic cell, using a copper mesh as a cathode and a titanium alloy as an anode to obtain chlorine and hydrogen, and performing continuous multi-stage electrolysis, i.e., supplementing new primary washing water to the primary washing water after the primary electrolysis for secondary electrolysis, supplementing new primary washing water to the primary washing water after the secondary electrolysis for tertiary electrolysis, and so on.
In the embodiment, the copper mesh is used as the cathode, so that the diffusion distance of chloride ions in the electrolyte can be effectively reduced, the electrolysis energy consumption is reduced, and the method is more suitable for preparing chlorine gas by electrolysis of low-concentration hydrochloric acid aqueous solution.
The steps in the method of the embodiment of the invention can be sequentially adjusted, combined and deleted according to actual needs.
The modules or units in the device of the embodiment of the invention can be combined, divided and deleted according to actual needs.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.
Claims (6)
1. A method for preparing battery-grade anhydrous iron phosphate by using sulfuric acid cinder is characterized by comprising the following steps:
the method comprises the following steps: reacting the sulfuric acid cinder with secondary phosphoric acid to obtain a crude product of iron phosphate, wherein the mass percentage concentration of the secondary phosphoric acid is 20-80%;
step two: dissolving the crude iron phosphate with second hydrochloric acid, and filtering to obtain a clear liquid and filter residue, wherein the mass percentage concentration of the second hydrochloric acid is 20-30%;
step three: distilling the clear liquid to obtain a gaseous hydrogen chloride and iron phosphate crystallization product;
step four: condensing gaseous hydrogen chloride to obtain fourth hydrochloric acid, rectifying the fourth hydrochloric acid to obtain second hydrochloric acid, and returning the second hydrochloric acid obtained in the step II to dissolve crude iron phosphate, wherein the mass percentage concentration of the fourth hydrochloric acid is less than 5%;
step five: washing the iron phosphate crystal product with secondary washing water to obtain refined iron phosphate and primary washing water, wherein the primary washing water is washing water containing 1-5% by mass of first hydrochloric acid, the primary washing water also contains chloride, hydroxide corresponding to cations of the chloride is insoluble in water, and the secondary washing water is the primary washing water without chloride;
step six: feeding the primary washing water into an electrolysis device for electrolysis to obtain chlorine, hydrogen, hydroxide precipitates and secondary washing water, discharging the hydrogen from a hydrogen discharge port, discharging the hydroxide precipitates from an electrolysis bath, returning the secondary washing water to the fifth step for washing the iron phosphate crystal product, and converting the secondary washing water into the primary washing water again;
step seven: introducing the chlorine into yellow phosphorus water, and absorbing the chlorine by the yellow phosphorus water to obtain a mixture of first phosphoric acid and third hydrochloric acid;
step eight: returning the mixture of the first phosphoric acid and the third hydrochloric acid to the step one to react with the sulfuric acid cinder;
step nine: feeding the refined ferric phosphate obtained in the fifth step into a drying and calcining device for calcining to obtain anhydrous ferric phosphate, wherein the drying and calcining device comprises a direct-fired hot-blast stove, a dynamic calcining tower, a first discharging cyclone device, a transfer fan, a rotary flash dryer, a first reel, a second discharging cyclone device, a second reel, a bag-type dust remover and an induced draft fan, an air outlet of the direct-fired hot-blast stove is communicated with an air inlet of the dynamic calcining tower to provide heat energy for the dynamic calcining tower, a discharge outlet at the top of the dynamic calcining tower is communicated with a feed inlet of the first discharging cyclone device, an anhydrous ferric phosphate outlet is arranged at the bottom of the first discharging cyclone device, an air outlet at the top of the first discharging cyclone device is communicated with an air inlet of the transfer fan, an air outlet of the transfer fan is communicated with an air inlet of the rotary flash dryer so that high-temperature gas flowing out of the dynamic calcining tower is sent into the rotary flash, the rotary flash evaporation dryer is characterized in that heat energy is provided for the rotary flash evaporation dryer, a feed inlet of the rotary flash evaporation dryer is connected with a first reel, refined iron phosphate to be dried is sent into the rotary flash evaporation dryer through the first reel, a discharge outlet at the top of the rotary flash evaporation dryer is communicated with a feed inlet of a second discharging cyclone device, an iron phosphate dihydrate outlet is formed in the bottom of the second discharging cyclone device and communicated with a feed inlet of a dynamic calcining tower through the second reel, the iron phosphate dihydrate outlet is sent into the dynamic calcining tower to be calcined, an air outlet of the second discharging cyclone device is communicated with an inlet of a bag-type dust collector, and an outlet of the bag-type dust collector is communicated with an induced draft fan.
2. The method for preparing battery-grade anhydrous iron phosphate by using the sulfuric acid cinder as claimed in claim 1, wherein: and a step of pretreating the primary washing water in the step five before electrolysis in the step six, wherein the pretreatment step is to pass the primary washing water through an evaporative condenser to concentrate the washing water with the mass percentage concentration of 1-5%, and the evaporative condenser is heated by adopting the hydrogen discharged in the step six.
3. The method for preparing battery-grade anhydrous iron phosphate by using the sulfuric acid cinder as claimed in claim 2, wherein: the evaporative condenser comprises an evaporating pot and a heating furnace, wherein a hydrogen pipeline, a drainage pipeline and a combustion-supporting gas pipeline are installed on the heating furnace, a water inlet pipeline, a water outlet pipeline, a condensation pipeline and a liquid level controller are installed on the evaporating pot, the evaporating pot penetrates through a circular hole in the top wall of the heating furnace and is embedded into the heating furnace, an outer ring wall on the upper portion of the evaporating pot is fixedly and hermetically connected with an inner ring wall of the circular hole in the top wall of the heating furnace, one end of the hydrogen pipeline is communicated with the bottom of a combustion chamber of the heating furnace, the other end of the hydrogen pipeline is communicated with a hydrogen discharge port of an electrolysis device, the bottom of the combustion chamber of the heating furnace is communicated with a drainage pipeline so as to discharge water generated after hydrogen combustion, the bottom of the combustion chamber of the heating furnace is communicated with the combustion-supporting, the device comprises an evaporative condenser, a water inlet pipeline, a water outlet pipeline, a water level controller, a control module, a first electromagnetic valve, a second electromagnetic valve, a first electromagnetic valve, a water level controller, a second electromagnetic valve, a first electromagnetic valve, a second electromagnetic valve, a water level controller, a first electromagnetic valve and a second electromagnetic valve, wherein the first washing water to be pretreated is introduced into the evaporative condenser, the water outlet pipeline is connected with the lower part of the evaporative condenser, the first washing water after evaporative concentration is introduced into an electrolytic bath, the second electromagnetic valve is installed on the water outlet pipeline, after water in the evaporative condenser is evaporated, water vapor forms condensate water at the top of the evaporative condenser, the condensate water is conveyed to a use point through a condensation pipeline from a water outlet at the top of the evaporative condenser and is used for washing an iron phosphate crystallization, The second electromagnetic valve is closed, when the water level in the evaporative condenser is at a high water level, the liquid level controller sends a signal that the water level is high to the control module, the control module controls the first electromagnetic valve to be closed, and the second electromagnetic valve is opened.
4. The method for preparing battery-grade anhydrous iron phosphate by using the sulfuric acid cinder as claimed in claim 3, wherein: the inside of the evaporative condenser is provided with a boiling wall which is in contact with raw water in the evaporative condenser and is used for heating the raw water, fine protrusions are densely distributed on one side of the boiling wall in contact with the raw water, and the free ends of the protrusions are arranged to be tips.
5. The method for preparing battery-grade anhydrous iron phosphate by using the sulfuric acid cinder as claimed in claim 3, wherein: the cross-section of the condensation pipeline is square, a plurality of condensation parts are inserted into the condensation pipeline along the length direction of the condensation pipeline at uniform intervals, each condensation part comprises two baffle plates, the two baffle plates are arranged in a reverse inclined mode, and each baffle plate is trapezoidal and is perpendicular to the side wall of the inner side of the exhaust pipeline.
6. The method for preparing battery-grade anhydrous iron phosphate by using the sulfuric acid cinder as claimed in claim 1, wherein: and step six, the electrolysis process of the primary washing water comprises the steps of enabling the pretreated primary washing water to pass through a cationic membrane electrolytic cell, taking a copper net as a cathode and a titanium alloy as an anode to obtain chlorine and hydrogen, and adopting a continuous multi-stage mode for electrolysis, namely supplementing new primary washing water to the primary washing water subjected to primary electrolysis for secondary electrolysis, supplementing new primary washing water to the primary washing water subjected to secondary electrolysis for tertiary electrolysis, and so on.
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| CN102092698A (en) * | 2010-12-03 | 2011-06-15 | 何侠 | Method for preparing sulfuric-acid burned slag into phosphate with chemical method |
| CN102491302A (en) * | 2011-12-15 | 2012-06-13 | 湖北万润新能源科技发展有限公司 | Battery-grade anhydrous iron phosphate and preparation method thereof |
| WO2014178788A1 (en) * | 2013-05-02 | 2014-11-06 | Easymining Sweden Ab | Production of phosphate compounds from materials containing phosphorus and at least one of iron and aluminium |
| CN105600764A (en) * | 2014-09-17 | 2016-05-25 | 常德云港生物科技有限公司 | Method for producing phosphate by using sulfuric acid sintering residue |
| CN107611433A (en) * | 2017-09-19 | 2018-01-19 | 江苏荣信环保科技有限公司 | A kind of method for preparing battery-grade iron phosphate using heavy metal sewage sludge and heavy metal spent acid |
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| CN102092698A (en) * | 2010-12-03 | 2011-06-15 | 何侠 | Method for preparing sulfuric-acid burned slag into phosphate with chemical method |
| CN102491302A (en) * | 2011-12-15 | 2012-06-13 | 湖北万润新能源科技发展有限公司 | Battery-grade anhydrous iron phosphate and preparation method thereof |
| WO2014178788A1 (en) * | 2013-05-02 | 2014-11-06 | Easymining Sweden Ab | Production of phosphate compounds from materials containing phosphorus and at least one of iron and aluminium |
| CN105600764A (en) * | 2014-09-17 | 2016-05-25 | 常德云港生物科技有限公司 | Method for producing phosphate by using sulfuric acid sintering residue |
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