CN108557795A - A kind of preparation method of LiFePO4 - Google Patents
A kind of preparation method of LiFePO4 Download PDFInfo
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- CN108557795A CN108557795A CN201810191155.6A CN201810191155A CN108557795A CN 108557795 A CN108557795 A CN 108557795A CN 201810191155 A CN201810191155 A CN 201810191155A CN 108557795 A CN108557795 A CN 108557795A
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B25/00—Phosphorus; Compounds thereof
- C01B25/16—Oxyacids of phosphorus; Salts thereof
- C01B25/26—Phosphates
- C01B25/45—Phosphates containing plural metal, or metal and ammonium
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- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G1/00—Mixtures of fertilisers belonging individually to different subclasses of C05
Abstract
The present invention discloses a kind of preparation method of LiFePO4.By ferroso-ferric oxide and phosphatase reaction, add iron powder reaction, then it filters, obtains the first filtrate and the first filter residue, the first obtained filtrate and ammonium hydroxide, hydrazine hydrate cocurrent are added in the liquid of bottom, then it filters, the second filtrate and the second filter residue are obtained, the second filter residue is washed with hot water, then by drying, sieving, except after iron, it is put into calcining in roaster, obtains anhydrous phosphoric acid ferrous iron；Pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, lithium phosphate, it is stirred in Ball-stirring mill, then the material after will be levigate is spray-dried, and the material after drying is calcined in sintering furnace, under nitrogen atmosphere, is discharged after being cooled to room temperature；It is crushed, sieved, except being vacuum-packed after iron.Present invention process is simple, at low cost, and magnetic foreign body is low, and impurity content is low.
Description
Technical field
The present invention relates to a kind of preparation methods of LiFePO4, belong to anode material of lithium battery technical field.
Background technology
LiFePO4 is a kind of new type lithium ion battery electrode material.Its main feature is that discharge capacity is big, and it is cheap, it is nontoxic
Property, do not cause environmental pollution.Just competitively realize industrialization production in countries in the world.But its tap density is low, influences capacitance.It is main
The production method wanted is high temperature solid phase synthesis, and product index is more stable.The performance of lithium ion battery depends primarily on positive and negative
Pole material, LiFePO4 are the things just occurred in recent years as the positive electrode of lithium ion battery, and domestic-developed goes out large capacity phosphorus
Sour lithium iron battery is in July, 2005.Its security performance with cycle life be other materials can not compared with, these are also exactly dynamic
The most important technical indicator of power battery.The 1C charge-discharge cycle service life is up to 2000 times.Single battery overcharged voltage 30V does not burn, and punctures
It does not explode.Lithium iron phosphate positive material makes high capacity lithium ion battery and is more easy to be used in series.To meet the frequent charge and discharge of electric vehicle
The needs of electricity.Have many advantages, such as it is nontoxic, pollution-free, have a safety feature, raw material sources are extensive, cheap, long lifespan is new
The ideal positive electrode of generation lithium ion battery.
But present conventional solid phase reaction has the following disadvantages：
1. presoma is ferric phosphate, general using ferrous oxidizer and calcium phosphate precipitation reaction, then need to be added a large amount of
Oxidant, cause it is of high cost, and the addition of oxidant can cause generate iron hydroxide.
2. in ferric phosphate and lithium carbonate mixed calcining, and needing that reducing agent is added, by ferric iron back at ferrous iron, then
This process can cause to consume a large amount of reducing agent, while need the amount of stringent control reducing agent, otherwise easy to produce iron simple substance and make
It is high at magnetic foreign body, and the extremely difficult control of this process.
Invention content
In view of this, the present invention provides a kind of preparation method of LiFePO4, eliminate presoma oxidation step and
The reduction step of LiFePO4 preparation process, at low cost, magnetic foreign body is low, and impurity content is low.
The present invention solves above-mentioned technical problem by following technological means：
A kind of preparation method of LiFePO4, is following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1-2 hours at being 60-70 DEG C in temperature, iron powder is then added,
Be 60-70 DEG C in temperature to react 1-2 hour, then filter, obtain the first filtrate and the first filter residue, by the first obtained filtrate and
Ammonium hydroxide, hydrazine hydrate cocurrent are added in the liquid of bottom, and bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3-3.5, while maintaining charging process
PH is 3-3.5, and the temperature for the process that feeds is 90-95 DEG C, continues after charging in temperature to be 90-95 DEG C of reaction 15-30min,
Mixing speed is 300-350r/min, is then filtered, and the second filtrate and the second filter residue are obtained, by the second filter residue with hot water wash to
The pH of wash water is 6-6.5, then after drying, sieving, removing iron, is put into calcining in roaster, while with nitrogen is entered, calcining is warm
Degree is 500-520 DEG C, and calcination time is 3-5 hours, obtains anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1),
It is stirred in Ball-stirring mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported to Ball-stirring mill by delivery pump
Top is stirred 30-60min, mixing speed 15-20r/min, and it is 30-40 DEG C that whipping process, which maintains temperature, then will mill
Material after thin is spray-dried, and the material after drying is calcined in sintering furnace, under nitrogen atmosphere, and calcination temperature is divided into 5
Warm area, the first warm area temperature are 650-670 DEG C, residence time of material 2-3h, and the second warm area temperature is 680-720 DEG C, material
Residence time is 1-2h, and third warm area temperature is 740-760 DEG C, residence time of material 4-5h, and four-temperature region temperature is 780-
815 DEG C, residence time of material 4-5h, the 5th warm area temperature is 780-800 DEG C, then residence time of material 2-3h starts
Cooling, cooling rate are 60-70 DEG C/h, are discharged after being cooled to room temperature；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen
Then gas vacuumizes packaging again.
The molar ratio of ferroso-ferric oxide and phosphoric acid is 1 in the step (1):7.5-8.5 a concentration of 2- of phosphoric acid
2.2mol/L, the iron powder of addition are 0.75-0.8 times of ferroso-ferric oxide weight ferric iron molal quantity, the first filtrate and hydrazine hydrate
Volume flow ratio is 5-10:0.2-0.5, a concentration of 3-5mol/L of hydrazine hydrate.
In the step (1) in roasting process, the oxygen volume content in roaster is maintained to be less than 0.1%.
Anhydrous phosphoric acid ferrous iron in the step (2), manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:
1-2：0.0002-0.0005:103-105, the built-in sphere volume of Ball-stirring mill account for the 85-90% of Ball-stirring mill volume, and the diameter of abrading-ball has 5
Kind, diameter is respectively 0.1cm, 0.2cm, 0.5cm, 1cm, 2cm, and number ratio is 8:6:4:2:1, delivery pump conveying capacity hourly
It is 1.2-1.5 times of Ball-stirring mill total measurement (volume), the temperature of spray drying is 85-95 DEG C, and when spray drying is protected using nitrogen,
When being calcined under nitrogen atmosphere, the volume fraction of oxygen in atmosphere in sintering furnace is maintained to be less than 0.01%.
At 15-25 DEG C, relative humidity is less than 30% for temperature control in constant temperature and humidity room in the step (3).
The volume that nitrogen is filled in the step (3) is 2-4m3, it is -0.085Mpa or less to be then evacuated to pressure.
Gas in the sintering furnace is after air-introduced machine is drawn, then is passed into roaster and in spray dryer.
The first filter residue return continues to dissolve together with ferroso-ferric oxide, and second filtrate obtains by condensing crystallizing
Compound nitrogen phosphate fertilizer.
The manganese dioxide and lithium phosphate purity are LITHIUM BATTERY.
This patent is prepared ferrous phosphate, keeps away using iron powder, phosphoric acid, ammonium hydroxide and a small amount of reducing agent hydrazine hydrate as raw material
Exempt to use oxidant, agent (nearly 0.5 ton of such as hydrogen peroxide) is needed to be oxidized according to experiment and produce reality, ferric phosphate per ton, due to this
Method need not additionally introduce other cations, such as sodium ion, only only small amounts of introducing ammonium ion, while not introduce other the moon
Ion such as sulfate radical, chlorion etc., so purity is high and cost of material is low.
LiFePO4 process is prepared finally, reducing agent need not be largely added and be used for restoring ferric iron, it is possible to
The amount for saving reducing agent, according to produce reality, the reducing agent (such as glucose about 100kg) that LiFePO4 per ton needs, while
Reduction process inevitably has a small amount of ferric ion to be reduced into iron simple substance, so final product magnetic foreign body is high,
1ppm or more is commonly reached, and the present invention need not largely add reducing agent, only be merely doped carbon, be gone back so avoiding
Original at iron simple substance so as to cause magnetic foreign body it is high.
Invention introduces manganese dioxide simultaneously, can effectively avoid the generation of fe, while introducing manganese member again
Element, doping manganese element can improve the voltage of LiFePO4.
The index of the finally obtained LiFePO4 of the present invention is as follows：
| Index | Iron content | Phosphorus content | D10 | D50 | D90 |
| Numerical value | 35-35.2% | 19.4-19.5% | 0.1-0.25μm | 1-2μm | 3-4.5μm |
| D100 | Ca | Mg | Na | Ni | Co |
| 6 μm of ＜ | ＜ 10ppm | ＜ 10ppm | ＜ 10ppm | ＜ 10ppm | ＜ 10ppm |
| Mn | Zn | Cu | Ti | Al | Si |
| 0.33-0.66% | ＜ 10ppm | ＜ 5ppm | ＜ 10ppm | ＜ 10ppm | ＜ 10ppm |
| Tap density | Sulphur | Chlorion | BET | Primary particle size | Carbon content |
| 1.35-1.5g/mL | 2-5ppm | 2-5ppm | 5-15m2/g | 10-15nm | 1-2% |
| Magnetic foreign body | Ferric iron | Compacted density | |||
| ＜ 1ppb | ＜ 0.05ppm | ＞ 2.7g/mL |
The beneficial effects of the invention are as follows：
1. at low cost, in molysite forerunner's production procedure, oxidant is not used, while in LiFePO4 preparation process,
There is no the consumption of reducing agent, greatly reduce cost, only this, product per ton can reduce by 2000 yuan or so of cost, and
Battery grade lithium phosphate is low relative to battery-level lithium carbonate price, further reduces cost.
2. in ferrous phosphate preparation process, the waste water containing ammonium phosphate is generated, Gao Pin can be obtained by condensing crystallizing
The compound nitrogen phosphate fertilizer of position, purity is high, and main content can reach 95%, and value is high, can further reduce the cost.
3. LiFePO4 preparation process through the invention can effectively avoid the generation of fe, also reduce three
The content of valence iron, so that magnetic foreign body reduces, the magnetic foreign body of LiFePO4 of the invention is down to 1ppb.
Specific implementation mode
Below with reference to specific embodiment, the present invention is described in detail, a kind of preparation of LiFePO4 of the present embodiment
Method is following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1-2 hours at being 60-70 DEG C in temperature, iron powder is then added,
Be 60-70 DEG C in temperature to react 1-2 hour, then filter, obtain the first filtrate and the first filter residue, by the first obtained filtrate and
Ammonium hydroxide, hydrazine hydrate cocurrent are added in the liquid of bottom, and bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3-3.5, while maintaining charging process
PH is 3-3.5, and the temperature for the process that feeds is 90-95 DEG C, continues after charging in temperature to be 90-95 DEG C of reaction 15-30min,
Mixing speed is 300-350r/min, is then filtered, and the second filtrate and the second filter residue are obtained, by the second filter residue with hot water wash to
The pH of wash water is 6-6.5, then after drying, sieving, removing iron, is put into calcining in roaster, while with nitrogen is entered, calcining is warm
Degree is 500-520 DEG C, and calcination time is 3-5 hours, obtains anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1),
It is stirred in Ball-stirring mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported to Ball-stirring mill by delivery pump
Top is stirred 30-60min, mixing speed 15-20r/min, and it is 30-40 DEG C that whipping process, which maintains temperature, then will mill
Material after thin is spray-dried, and the material after drying is calcined in sintering furnace, under nitrogen atmosphere, and calcination temperature is divided into 5
Warm area, the first warm area temperature are 650-670 DEG C, residence time of material 2-3h, and the second warm area temperature is 680-720 DEG C, material
Residence time is 1-2h, and third warm area temperature is 740-760 DEG C, residence time of material 4-5h, and four-temperature region temperature is 780-
815 DEG C, residence time of material 4-5h, the 5th warm area temperature is 780-800 DEG C, then residence time of material 2-3h starts
Cooling, cooling rate are 60-70 DEG C/h, are discharged after being cooled to room temperature；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen
Then gas vacuumizes packaging again.
The molar ratio of ferroso-ferric oxide and phosphoric acid is 1 in the step (1):7.5-8.5 a concentration of 2- of phosphoric acid
2.2mol/L, the iron powder of addition are 0.75-0.8 times of ferroso-ferric oxide weight ferric iron molal quantity, the first filtrate and hydrazine hydrate
Volume flow ratio is 5-10:0.2-0.5, a concentration of 3-5mol/L of hydrazine hydrate.
In the step (1) in roasting process, the oxygen volume content in roaster is maintained to be less than 0.1%.
Anhydrous phosphoric acid ferrous iron in the step (2), manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:
1-2：0.0002-0.0005:103-105, the built-in sphere volume of Ball-stirring mill account for the 85-90% of Ball-stirring mill volume, and the diameter of abrading-ball has 5
Kind, diameter is respectively 0.1cm, 0.2cm, 0.5cm, 1cm, 2cm, and number ratio is 8:6:4:2:1, delivery pump conveying capacity hourly
It is 1.2-1.5 times of Ball-stirring mill total measurement (volume), the temperature of spray drying is 85-95 DEG C, and when spray drying is protected using nitrogen,
When being calcined under nitrogen atmosphere, the volume fraction of oxygen in atmosphere in sintering furnace is maintained to be less than 0.01%.
At 15-25 DEG C, relative humidity is less than 30% for temperature control in constant temperature and humidity room in the step (3).
The volume that nitrogen is filled in the step (3) is 2-4m3, it is -0.085Mpa or less to be then evacuated to pressure.
Gas in the sintering furnace is after air-introduced machine is drawn, then is passed into roaster and in spray dryer.
The first filter residue return continues to dissolve together with ferroso-ferric oxide, and second filtrate obtains by condensing crystallizing
Compound nitrogen phosphate fertilizer.
The manganese dioxide and lithium phosphate purity are LITHIUM BATTERY.
Embodiment 1
A kind of preparation method of LiFePO4, is following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1.5 hours at being 65 DEG C in temperature, iron powder is then added, in temperature
Degree reacts 1.5 hours for 65 DEG C, then filters, obtains the first filtrate and the first filter residue, by the first obtained filtrate and ammonium hydroxide, water
It closes hydrazine cocurrent to be added in the liquid of bottom, bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3.35, while maintaining the pH of charging process to be
3.35, the temperature for the process that feeds is 92.5 DEG C, continues after charging in temperature to be 92.55 DEG C of reaction 25min, mixing speed is
Then 330r/min is filtered, obtain the second filtrate and the second filter residue, is with the pH that hot water is washed to wash water by the second filter residue
6.25, then after drying, sieving, removing iron, it is put into calcining in roaster, while with nitrogen is entered, calcination temperature is 515 DEG C,
Calcination time is 4.5 hours, obtains anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1),
It is stirred in Ball-stirring mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported to Ball-stirring mill by delivery pump
Top, is stirred 45min, mixing speed 18r/min, and it is 35 DEG C that whipping process, which maintains temperature, then will be levigate after object
Material is spray-dried, it is dry after material calcined in sintering furnace, under nitrogen atmosphere, calcination temperature is divided into 5 warm areas, first
Warm area temperature is 665 DEG C, residence time of material 2.5h, and the second warm area temperature is 705 DEG C, residence time of material 2h, third
Warm area temperature is 755 DEG C, residence time of material 4.5h, and four-temperature region temperature is 800 DEG C, residence time of material 4.5h, the
Five warm area temperature are 795 DEG C, residence time of material 2.8h, then start to cool down, and cooling rate is 65 DEG C/h, is cooled to room temperature
After discharge；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen
Then gas vacuumizes packaging again.
The molar ratio of ferroso-ferric oxide and phosphoric acid is 1 in the step (1):8.15, a concentration of 2.12mol/L of phosphoric acid,
The iron powder of addition is 0.78 times of ferroso-ferric oxide weight ferric iron molal quantity, and the volume flow ratio of the first filtrate and hydrazine hydrate is 9:
0.4, a concentration of 4.1mol/L of hydrazine hydrate.
In the step (1) in roasting process, the oxygen volume content in roaster is maintained to be less than 0.1%.
Anhydrous phosphoric acid ferrous iron in the step (2), manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:
1.5：0.00035:104, the built-in sphere volume of Ball-stirring mill accounts for the 88% of Ball-stirring mill volume, and the diameter of abrading-ball has 5 kinds, and diameter is respectively
0.1cm, 0.2cm, 0.5cm, 1cm, 2cm, number ratio are 8:6:4:2:1, delivery pump conveying capacity hourly is that Ball-stirring mill always holds
Long-pending 1.3 times, the temperature of spray drying are 89 DEG C, and when spray drying is protected using nitrogen, when being calcined under nitrogen atmosphere, ties up
The volume fraction for holding oxygen in atmosphere in sintering furnace is less than 0.01%.
At 19 DEG C, relative humidity is less than 30% for temperature control in constant temperature and humidity room in the step (3).
The volume that nitrogen is filled in the step (3) is 3.5m3, it is -0.085Mpa or less to be then evacuated to pressure.
Gas in the sintering furnace is after air-introduced machine is drawn, then is passed into roaster and in spray dryer.
The first filter residue return continues to dissolve together with ferroso-ferric oxide, and second filtrate obtains by condensing crystallizing
Compound nitrogen phosphate fertilizer.
The manganese dioxide and lithium phosphate purity are LITHIUM BATTERY.
The index for finally collecting obtained LiFePO4 is as follows：
| Index | Iron content | Phosphorus content | D10 | D50 | D90 |
| Numerical value | 35.12% | 19.43% | 0.21μm | 1.2μm | 3.75μm |
| D100 | Ca | Mg | Na | Ni | Co |
| 5.7μm | 3.8ppm | 4.1ppm | 2.1ppm | 3.7ppm | 6.4ppm |
| Mn | Zn | Cu | Ti | Al | Si |
| 0.5% | 2.1ppm | 2.5ppm | 1.7ppm | 1.7ppm | 3.8ppm |
| Tap density | Sulphur | Chlorion | BET | Primary particle size | Carbon content |
| 1.38g/mL | 2.8ppm | 3.8ppm | 7.2m2/g | 11.5nm | 1.5% |
| Magnetic foreign body | Ferric iron | Compacted density | |||
| 0.3ppb | 0.02ppm | 2.75g/mL |
Embodiment 2
A kind of preparation method of LiFePO4, is following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1.5 hours at being 65 DEG C in temperature, iron powder is then added, in temperature
Degree reacts 1.5 hours for 65 DEG C, then filters, obtains the first filtrate and the first filter residue, by the first obtained filtrate and ammonium hydroxide, water
It closes hydrazine cocurrent to be added in the liquid of bottom, bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3.35, while maintaining the pH of charging process to be
3.35, the temperature for the process that feeds is 92.5 DEG C, continues after charging in temperature to be 92.55 DEG C of reaction 25min, mixing speed is
Then 330r/min is filtered, obtain the second filtrate and the second filter residue, is with the pH that hot water is washed to wash water by the second filter residue
6.25, then after drying, sieving, removing iron, it is put into calcining in roaster, while with nitrogen is entered, calcination temperature is 515 DEG C,
Calcination time is 4.5 hours, obtains anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1),
It is stirred in Ball-stirring mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported to Ball-stirring mill by delivery pump
Top, is stirred 45min, mixing speed 18r/min, and it is 35 DEG C that whipping process, which maintains temperature, then will be levigate after object
Material is spray-dried, it is dry after material calcined in sintering furnace, under nitrogen atmosphere, calcination temperature is divided into 5 warm areas, first
Warm area temperature is 665 DEG C, residence time of material 2.5h, and the second warm area temperature is 705 DEG C, residence time of material 2h, third
Warm area temperature is 755 DEG C, residence time of material 4.5h, and four-temperature region temperature is 800 DEG C, residence time of material 4.5h, the
Five warm area temperature are 795 DEG C, residence time of material 2.8h, then start to cool down, and cooling rate is 65 DEG C/h, is cooled to room temperature
After discharge；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen
Then gas vacuumizes packaging again.
The molar ratio of ferroso-ferric oxide and phosphoric acid is 1 in the step (1):8.15, a concentration of 2.15mol/L of phosphoric acid,
The iron powder of addition is 0.79 times of ferroso-ferric oxide weight ferric iron molal quantity, and the volume flow ratio of the first filtrate and hydrazine hydrate is 9:
0.35, a concentration of 4.3mol/L of hydrazine hydrate.
In the step (1) in roasting process, the oxygen volume content in roaster is maintained to be less than 0.1%.
Anhydrous phosphoric acid ferrous iron in the step (2), manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:
1.3：0.00045:104, the built-in sphere volume of Ball-stirring mill accounts for the 89% of Ball-stirring mill volume, and the diameter of abrading-ball has 5 kinds, and diameter is respectively
0.1cm, 0.2cm, 0.5cm, 1cm, 2cm, number ratio are 8:6:4:2:1, delivery pump conveying capacity hourly is that Ball-stirring mill always holds
Long-pending 1.2-1.5 times, the temperature of spray drying are 86 DEG C, and when spray drying is protected using nitrogen, is calcined under nitrogen atmosphere
When, maintain the volume fraction of oxygen in atmosphere in sintering furnace to be less than 0.01%.
At 21 DEG C, relative humidity is less than 30% for temperature control in constant temperature and humidity room in the step (3).
The volume that nitrogen is filled in the step (3) is 3m3, it is -0.085Mpa or less to be then evacuated to pressure.
Gas in the sintering furnace is after air-introduced machine is drawn, then is passed into roaster and in spray dryer.
The first filter residue return continues to dissolve together with ferroso-ferric oxide, and second filtrate obtains by condensing crystallizing
Compound nitrogen phosphate fertilizer.
The manganese dioxide and lithium phosphate purity are LITHIUM BATTERY.
The index of the finally obtained LiFePO4 of the present invention is as follows：
| Index | Iron content | Phosphorus content | D10 | D50 | D90 |
| Numerical value | 35.1% | 19.42% | 0.19μm | 1.7μm | 4.1μm |
| D100 | Ca | Mg | Na | Ni | Co |
| 5.7μm | 1.7ppm | 4.1ppm | 3.1ppm | 5.2ppm | 4.3ppm |
| Mn | Zn | Cu | Ti | Al | Si |
| 0.42% | 1.3ppm | 2.1ppm | 4.0ppm | 3.5ppm | 4.1ppm |
| Tap density | Sulphur | Chlorion | BET | Primary particle size | Carbon content |
| 1.39g/mL | 4.1ppm | 2.8ppm | 11.3m2/g | 12.5nm | 1.8% |
| Magnetic foreign body | Ferric iron | Compacted density | |||
| 0.6ppb | 0.02ppm | 2.78g/mL |
Embodiment 3
A kind of preparation method of LiFePO4, is following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1.8 hours at being 67 DEG C in temperature, iron powder is then added, in temperature
Degree reacts 1.8 hours for 67 DEG C, then filters, obtains the first filtrate and the first filter residue, by the first obtained filtrate and ammonium hydroxide, water
It closes hydrazine cocurrent to be added in the liquid of bottom, bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3.35, while maintaining the pH of charging process to be
3.35, the temperature for the process that feeds is 91 DEG C, continues after charging in temperature to be 91 DEG C of reactions 28min, mixing speed 315r/
Then min is filtered, obtain the second filtrate and the second filter residue, and it is 6.35 that the second filter residue, which is washed with hot water to the pH of wash water, then
After drying, sieving, removing iron, it is put into calcining in roaster, while with nitrogen is entered, calcination temperature is 512 DEG C, and calcination time is
4.3 hours, obtain anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1),
It is stirred in Ball-stirring mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported to Ball-stirring mill by delivery pump
Top, is stirred 50min, mixing speed 18r/min, and it is 37 DEG C that whipping process, which maintains temperature, then will be levigate after object
Material is spray-dried, it is dry after material calcined in sintering furnace, under nitrogen atmosphere, calcination temperature is divided into 5 warm areas, first
Warm area temperature is 665 DEG C, residence time of material 2.7h, and the second warm area temperature is 715 DEG C, residence time of material 1.8h, the
Three-temperature-zone temperature is 755 DEG C, residence time of material 5h, and four-temperature region temperature is 810 DEG C, residence time of material 5h, the 5th
Warm area temperature is 795 DEG C, residence time of material 2h, then starts to cool down, and cooling rate is 66 DEG C/h, is gone out after being cooled to room temperature
Material；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen
Then gas vacuumizes packaging again.
The molar ratio of ferroso-ferric oxide and phosphoric acid is 1 in the step (1):8.15, a concentration of 2.15mol/L of phosphoric acid,
The iron powder of addition is 0.79 times of ferroso-ferric oxide weight ferric iron molal quantity, and the volume flow ratio of the first filtrate and hydrazine hydrate is 9:
0.35, a concentration of 4.3mol/L of hydrazine hydrate.
In the step (1) in roasting process, the oxygen volume content in roaster is maintained to be less than 0.1%.
Anhydrous phosphoric acid ferrous iron in the step (2), manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:
1.3：0.00045:104, the built-in sphere volume of Ball-stirring mill accounts for the 89% of Ball-stirring mill volume, and the diameter of abrading-ball has 5 kinds, and diameter is respectively
0.1cm, 0.2cm, 0.5cm, 1cm, 2cm, number ratio are 8:6:4:2:1, delivery pump conveying capacity hourly is that Ball-stirring mill always holds
Long-pending 1.2-1.5 times, the temperature of spray drying are 86 DEG C, and when spray drying is protected using nitrogen, is calcined under nitrogen atmosphere
When, maintain the volume fraction of oxygen in atmosphere in sintering furnace to be less than 0.01%.
At 21 DEG C, relative humidity is less than 30% for temperature control in constant temperature and humidity room in the step (3).
The volume that nitrogen is filled in the step (3) is 3m3, it is -0.085Mpa or less to be then evacuated to pressure.
Gas in the sintering furnace is after air-introduced machine is drawn, then is passed into roaster and in spray dryer.
The first filter residue return continues to dissolve together with ferroso-ferric oxide, and second filtrate obtains by condensing crystallizing
Compound nitrogen phosphate fertilizer.
The manganese dioxide and lithium phosphate purity are LITHIUM BATTERY.
The index of the finally obtained LiFePO4 of the present invention is as follows：
| Index | Iron content | Phosphorus content | D10 | D50 | D90 |
| Numerical value | 35.11% | 19.41% | 0.18μm | 1.8μm | 4.2μm |
| D100 | Ca | Mg | Na | Ni | Co |
| 5.6μm | 1.6ppm | 4.0ppm | 3.7ppm | 5.2ppm | 4.3ppm |
| Mn | Zn | Cu | Ti | Al | Si |
| 0.42% | 1.4ppm | 2.0ppm | 4.7ppm | 3.5ppm | 4.1ppm |
| Tap density | Sulphur | Chlorion | BET | Primary particle size | Carbon content |
| 1.40g/mL | 4.0ppm | 3.2ppm | 10.4m2/g | 13nm | 1.8% |
| Magnetic foreign body | Ferric iron | Compacted density | |||
| 0.5ppb | 0.01ppm | 2.73g/mL |
Embodiment 4
A kind of preparation method of LiFePO4, is following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1.8 hours at being 66 DEG C in temperature, iron powder is then added, in temperature
Degree reacts 1.5 hours for 66 DEG C, then filters, obtains the first filtrate and the first filter residue, by the first obtained filtrate and ammonium hydroxide, water
It closes hydrazine cocurrent to be added in the liquid of bottom, bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3.36, while maintaining the pH of charging process to be
3.36, the temperature for the process that feeds is 91 DEG C, continues after charging in temperature to be 94 DEG C of reactions 25min, mixing speed 335r/
Then min is filtered, obtain the second filtrate and the second filter residue, and it is 6.3 that the second filter residue, which is washed with hot water to the pH of wash water, then
After drying, sieving, removing iron, it is put into calcining in roaster, while with nitrogen is entered, calcination temperature is 512 DEG C, and calcination time is
4.2 hours, obtain anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1),
It is stirred in Ball-stirring mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported to Ball-stirring mill by delivery pump
Top, is stirred 50min, mixing speed 18r/min, and it is 37 DEG C that whipping process, which maintains temperature, then will be levigate after object
Material is spray-dried, it is dry after material calcined in sintering furnace, under nitrogen atmosphere, calcination temperature is divided into 5 warm areas, first
Warm area temperature is 666 DEG C, residence time of material 2.5h, and the second warm area temperature is 712 DEG C, residence time of material 1.5h, the
Three-temperature-zone temperature is 750 DEG C, residence time of material 4.5h, and four-temperature region temperature is 810 DEG C, residence time of material 4.6h,
5th warm area temperature is 790 DEG C, residence time of material 2.5h, then starts to cool down, and cooling rate is 68 DEG C/h, is cooled to room
It discharges after temperature；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen
Then gas vacuumizes packaging again.
The molar ratio of ferroso-ferric oxide and phosphoric acid is 1 in the step (1):8.2, a concentration of 2.13mol/L of phosphoric acid add
The iron powder entered is 0.78 times of ferroso-ferric oxide weight ferric iron molal quantity, and the volume flow ratio of the first filtrate and hydrazine hydrate is 8:
0.3, a concentration of 4.3mol/L of hydrazine hydrate.
In the step (1) in roasting process, the oxygen volume content in roaster is maintained to be less than 0.1%.
Anhydrous phosphoric acid ferrous iron in the step (2), manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:
1.8：0.00025:104.5, the built-in sphere volume of Ball-stirring mill accounts for the 89% of Ball-stirring mill volume, and the diameter of abrading-ball has 5 kinds, diameter difference
For 0.1cm, 0.2cm, 0.5cm, 1cm, 2cm, number ratio is 8:6:4:2:1, delivery pump conveying capacity hourly is that Ball-stirring mill is total
1.35 times of volume, the temperature of spray drying are 89 DEG C, and when spray drying is protected using nitrogen, is calcined under nitrogen atmosphere
When, maintain the volume fraction of oxygen in atmosphere in sintering furnace to be less than 0.01%.
At 19 DEG C, relative humidity is less than 30% for temperature control in constant temperature and humidity room in the step (3).
The volume that nitrogen is filled in the step (3) is 3.8m3, it is -0.085Mpa or less to be then evacuated to pressure.
Gas in the sintering furnace is after air-introduced machine is drawn, then is passed into roaster and in spray dryer.
The first filter residue return continues to dissolve together with ferroso-ferric oxide, and second filtrate obtains by condensing crystallizing
Compound nitrogen phosphate fertilizer.
The manganese dioxide and lithium phosphate purity are LITHIUM BATTERY.
The index of the finally obtained LiFePO4 of the present invention is as follows：
| Index | Iron content | Phosphorus content | D10 | D50 | D90 |
| Numerical value | 35.12% | 19.48% | 0.22μm | 1.8μm | 4.3μm |
| D100 | Ca | Mg | Na | Ni | Co |
| 5.8μm | 2.8ppm | 2.9ppm | 1.8ppm | 3.0ppm | 2.1ppm |
| Mn | Zn | Cu | Ti | Al | Si |
| 0.60% | 3.3ppm | 1.0ppm | 4.3ppm | 5.1ppm | 6.0ppm |
| Tap density | Sulphur | Chlorion | BET | Primary particle size | Carbon content |
| 1.39g/mL | 2.8ppm | 2.5ppm | 8.9m2/g | 12nm | 1.15% |
| Magnetic foreign body | Ferric iron | Compacted density | |||
| 0.5ppb | 0.04ppm | 2.72g/mL |
By the ferric phosphate lithium cell of the material preparation of embodiment 1,2,3,4 and the ferric phosphate lithium cell using ferric phosphate preparation
It is compared, self-discharge rate is as follows：
Finally illustrate, the above examples are only used to illustrate the technical scheme of the present invention and are not limiting, although with reference to compared with
Good embodiment describes the invention in detail, it will be understood by those of ordinary skill in the art that, it can be to the skill of the present invention
Art scheme is modified or replaced equivalently, and without departing from the objective and range of technical solution of the present invention, should all be covered at this
In the right of invention.
Claims (9)
1. a kind of preparation method of LiFePO4, which is characterized in that be following steps：
(1) it by ferroso-ferric oxide and phosphatase reaction, is reacted 1-2 hours at being 60-70 DEG C in temperature, iron powder is then added, in temperature
Degree reacts 1-2 hours for 60-70 DEG C, then filters, obtains the first filtrate and the first filter residue, by the first obtained filtrate and ammonia
Water, hydrazine hydrate cocurrent are added in the liquid of bottom, and bottom liquid is phosphoric acid solution, and the pH of bottom liquid is 3-3.5, while maintaining the pH of charging process
For 3-3.5, the temperature for the process that feeds is 90-95 DEG C, continues after charging in temperature to be 90-95 DEG C of reaction 15-30min, stir
It is 300-350r/min to mix speed, then filters, obtains the second filtrate and the second filter residue, and the second filter residue is washed with hot water to washing
The pH of water is 6-6.5, then by drying, sieving, except after iron, being put into calcining in roaster, while it is same enter nitrogen, calcination temperature
It it is 500-520 DEG C, calcination time is 3-5 hours, obtains anhydrous phosphoric acid ferrous iron；
(2) pure water is added in anhydrous phosphoric acid ferrous iron, manganese dioxide, Macrogol 4000, the lithium phosphate obtained step (1), is stirring
It mixes and is stirred in mill, while Ball-stirring mill bottom is provided with delivery pump, the material of bottom is transported at the top of Ball-stirring mill by delivery pump,
Be stirred 30-60min, mixing speed 15-20r/min, it is 30-40 DEG C that whipping process, which maintains temperature, then will be levigate after
Material be spray-dried, it is dry after material calcined in sintering furnace, under nitrogen atmosphere, calcination temperature is divided into 5 warm areas,
First warm area temperature is 650-670 DEG C, residence time of material 2-3h, and the second warm area temperature is 680-720 DEG C, when material stop
Between be 1-2h, third warm area temperature be 740-760 DEG C, residence time of material 4-5h, four-temperature region temperature be 780-815 DEG C,
Residence time of material is 4-5h, and the 5th warm area temperature is 780-800 DEG C, residence time of material 2-3h, then starts to cool down, and is dropped
Warm speed is 60-70 DEG C/h, is discharged after being cooled to room temperature；
(3) the cooling material for obtaining step (2) is crushed in constant temperature and humidity room, is sieved, except after iron, being filled with nitrogen, so
Vacuumize packaging again afterwards.
2. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：Four oxygen in the step (1)
The molar ratio for changing three-iron and phosphoric acid is 1:The iron powder of 7.5-8.5, a concentration of 2-2.2mol/L of phosphoric acid, addition are ferroso-ferric oxide
The volume flow ratio of 0.75-0.8 times of weight ferric iron molal quantity, the first filtrate and hydrazine hydrate is 5-10:0.2-0.5, hydrazine hydrate
A concentration of 3-5mol/L.
3. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：It is being roasted in the step (1)
During burning, the oxygen volume content in roaster is maintained to be less than 0.1%.
4. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：It is anhydrous in the step (2)
Ferrous phosphate, manganese dioxide, Macrogol 4000, lithium phosphate molar ratio be 100:1-2：0.0002-0.0005:103-105,
The built-in sphere volume of Ball-stirring mill accounts for the 85-90% of Ball-stirring mill volume, and the diameter of abrading-ball has 5 kinds, diameter be respectively 0.1cm, 0.2cm,
0.5cm, 1cm, 2cm, number ratio are 8:6:4:2:1, delivery pump conveying capacity hourly is the 1.2-1.5 of Ball-stirring mill total measurement (volume)
Times, the temperature of spray drying is 85-95 DEG C, and when spray drying is protected using nitrogen, when being calcined under nitrogen atmosphere, maintains burning
The volume fraction of oxygen is less than 0.01% in atmosphere in freezing of a furnace.
5. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：Constant temperature in the step (3)
At 15-25 DEG C, relative humidity is less than 30% for temperature control in constant humidity room.
6. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：It is filled in the step (3)
The volume of nitrogen is 2-4m3, it is -0.085Mpa or less to be then evacuated to pressure.
7. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：Gas in the sintering furnace
After air-introduced machine is drawn, then it is passed into roaster and in spray dryer.
8. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：First filter residue return with
Ferroso-ferric oxide continues to dissolve together, and second filtrate obtains compound nitrogen phosphate fertilizer by condensing crystallizing.
9. a kind of preparation method of LiFePO4 according to claim 1, it is characterised in that：The manganese dioxide and phosphoric acid
Lithium purity is LITHIUM BATTERY.
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