CN103708565B - The preparation method of FeF3 - Google Patents

Abstract

The present invention relates to the field of preparation of chemical materials, in particular to a method for preparing FeF ₃ , comprising the following steps: uniformly mixing iron ore or minerals containing Fe ₂ O ₃ with fluoride to obtain a mixture; reacting the mixture to obtain a gaseous FeF ₃ . The preparation method of FeF of the present invention, can adopt known reaction device in the art to complete _the preparation process, _and the production process step _is simple; The condition requirements are low and the production cost is low.

Description

The preparation method of FeF3

technical field

The invention relates to the field of preparation of chemical materials, in particular to a method for preparing _FeF3 .

Background technique

Iron fluoride has the advantages of being cheap, non-toxic, environmentally friendly, and high theoretical capacity; and iron fluoride can be used as the cathode material of metal fluoride in lithium secondary batteries, so it has attracted much attention. Among many transition metals, Fe element has the advantages of low price, abundant reserves, and environmental friendliness. Therefore, _FeF3 has become one of the preferred materials for new reversible chemical conversion mechanism materials. When FeF ₃ is used as a positive electrode material, there are two different lithium storage mechanisms during charging and discharging: one is a typical intercalation and delithiation mechanism, that is, a Li ⁺ is reversibly inserted/extracted in the FeF ₃ crystal structure, Accompanied by the transformation of Fe ³⁺ /Fe ²⁺ ; the other is a reversible chemical conversion mechanism, that is, FeF ₃ continues to undergo electrochemical reduction reaction with two Li ⁺ , forming Fe nanoparticles and LiF.

In the related art, the main methods for preparing FeF ₃ are as follows: 1. Generating amorphous FeF ₃ by reacting Fe ₂ O ₃ or FeCl ₃ with dry HF gas; 2. Mixing F ₂ with metal Fe or Fe ₂ O ₃ to obtain FeF ₃ ; 3. Use Fe(OH) ₃ to precipitate and react with hydrofluoric acid, then evaporate excess water and HF to obtain FeF ₃ ; 4. Use ionic liquid as solvent and fluorine source to prepare FeF ₃ 5. Dissolving the inorganic iron salt in the alcohol solvent to obtain the iron-containing alcohol solution; dispersing the inorganic fluorine source into the iron-containing alcohol solution, transferring the solution to a hydrothermal reaction kettle for heat treatment, and obtaining FeF ₃ after cooling. However, the preparation of FeF ₃ by the above method is complicated and the production cost is high.

Contents of the invention

The object of the present invention is to provide the preparation method of _FeF3 , to solve above-mentioned problem.

Provide _FeF in the embodiment of the present invention The preparation method comprises the following steps:

Mix iron ore or minerals containing Fe ₂ O ₃ and fluoride evenly to obtain a mixture;

The mixture is reacted to obtain gaseous _FeF3 .

Further, the mixture is reacted to obtain gaseous FeF _3. After the step, the following steps are also included:

The gaseous FeF ₃ is collected, cooled and purified to obtain FeF ₃ with a purity of 99% to 99.99%.

Further, the step is to uniformly mix iron ore or Fe ₂ O ₃ -containing minerals with fluoride to obtain a mixture in which the fluoride is any of the following solid fluorides: NaF, NH ₄ F, NH ₄ HF ₂ , CaF ₂ and AlF ₃ , iron ore or minerals containing Fe ₂ O ₃ and solid fluorides are all less than 3mm in particle size.

Preferably, in the step, the iron ore or the mineral containing Fe ₂ O ₃ and the fluoride are uniformly mixed to obtain the mixture, and the mass percentage of the fluoride in the mixture is 20%-90%.

Preferably, the step reacts the mixture to obtain gaseous FeF ₃ , which specifically includes the following steps:

pressing the mixture into billets;

Introduce air, carry out calcining, obtain the mixed gas of gaseous FeF ₃ and other gaseous substances;

Cool the mixed gas below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances;

Separating the gas-solid mixture to obtain solid FeF ₃ ;

The solid FeF ₃ is gasified to obtain gaseous FeF ₃ .

Preferably, in the step of introducing air and performing calcination to obtain the mixed gas of gaseous FeF ₃ and other gaseous substances, the calcination temperature is 900°C-1300°C, and the calcination time is 3h-15h.

Preferably, when gasifying solid FeF ₃ to obtain gaseous FeF ₃ , the gasification temperature is 1000°C to 1400°C.

Further, the fluoride is hydrofluoric acid, and the steps are to mix iron ore or _Fe2O3 -containing minerals with the fluoride evenly, and the specific steps for obtaining the mixture are _:

Mix iron ore or minerals containing Fe ₂ O ₃ with hydrofluoric acid to obtain a mixture. The mass percentage of hydrofluoric acid in the mixture is 20% to 90%; the mass concentration of hydrofluoric acid is 20% to 40%. .

Preferably, the step reacts the mixture to obtain gaseous FeF _The concrete steps are:

The mixture is reacted at 100-200°C for 3h-15h to generate solid FeF ₃ ;

Raise the temperature of solid FeF ₃ to 1000°C to 1400°C for gasification to obtain gaseous FeF ₃ .

Preferably, the iron ore or _{Fe2O3 -} containing mineral is any one of the following: bauxite, magnetite, hematite, limonite, siderite, iron sulfide, iron Silicate ore, waste containing Fe ₂ O ₃ .

The preparation method of _FeF3 in the above-mentioned embodiments of the present invention can be completed by using a reaction device known in the art to complete the preparation process, and the production process steps _are simple; moreover, cheap iron ore or _Fe2O3 -containing minerals and fluorides are used as the main The raw materials and reaction conditions are low, and the production cost is low.

Detailed ways

The present invention will be further described in detail through specific implementation examples below.

Embodiments of the present invention provide _FeF The preparation method comprises the following steps:

Step 101: uniformly mixing iron ore or _Fe2O3 -containing minerals with _fluoride to obtain a mixture;

Step 102: reacting the mixture to obtain gaseous FeF ₃ .

In the preparation method of FeF ₃ provided in the examples of the present invention, the F element in the fluoride (AF _z ) and the fluorine affinity in iron ore or Fe ₂ O ₃ -containing minerals (M _x O _y nFe ₂ O ₃ ) are used The element Fe reacts, and its reaction formula is:

M _x O _y nFe ₂ O ₃ +AF _z →M _x O _y +A ₂ O _z +FeF ₃

Through the above reaction, high fluorination of iron ore or Fe ₂ O ₃ -containing minerals is realized, and gaseous high-purity FeF ₃ is generated. The preparation method of FeF ₃ provided in this example simplifies the production process steps, and uses cheap iron ore or Fe ₂ O ₃ -containing minerals and fluorides as the main raw materials, so the production cost is low. In addition, the FeF prepared by the preparation method provided in this example has _small particle size, no impurities, high cleanliness, low energy consumption in the reaction process, no toxic fluorine source in the raw materials, and low requirements on reaction conditions and reaction equipment.

In order to improve the FeF prepared by the preparation method provided in this embodiment ₃ purity, so preferably after step 102, the following steps are also included:

Step 103: Collect, cool, and purify the gaseous FeF ₃ to obtain FeF ₃ with a purity of 99%-99.99%.

The above collection, cooling and purification methods can be realized by using collection, cooling and purification methods and devices known in the art.

In this example, the fluoride in the raw material can be any of the following solid fluorides: NaF, NH ₄ F, NH ₄ HF ₂ , CaF ₂ and AlF ₃ , iron ore or Fe ₂ O ₃ The particle size of minerals and solid fluoride is less than 3mm. Since the sources of NaF, NH ₄ F, NH ₄ HF ₂ , CaF ₂ and AlF ₃ are extensive and the cost is low, the production cost of preparing FeF ₃ is further reduced. In addition, controlling the particle size of fluoride and iron ore or Fe ₂ O ₃ -containing minerals below 3mm can make the two solid raw materials can be mixed, the reaction is more complete, and the yield of the reaction is further improved.

When the fluoride is _a solid fluoride, in the mixture composed of iron ore or _Fe2O3 -containing minerals and the fluoride, the mass fraction of the fluoride is preferably 20%-90%. This enables more Fe to participate in the reaction, helping to increase the yield. In addition, in this embodiment, it is preferable to directly generate gaseous FeF ₃ by increasing the reaction temperature. Preferably, step 102 specifically includes the following steps:

Step 10211: pressing the mixture into a billet;

Step 10212: Introducing air for calcination to obtain a mixed gas of gaseous FeF ₃ and other gaseous substances;

Step 10213: cooling the mixed gas to below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances;

Step 10214: Separating the gas-solid mixture to obtain solid FeF ₃ ;

Step 10215: Gasify the solid FeF ₃ to obtain gaseous FeF ₃ .

By pressing the mixture into a billet, the calcination of the subsequent process can be made more complete, and the yield of FeF ₃ can be improved. The solid mixture is directly calcined to obtain gaseous FeF ₃ , which simplifies the preparation process and improves the preparation efficiency. By introducing air during the calcining process, the raw materials can be fully calcined and the reaction can be more complete.

In addition, the purity of the prepared gaseous FeF ₃ can be improved by controlling the calcination temperature and calcination time. Preferably, the calcination temperature is 900°C-1300°C, and the calcination time is 3h-15h. If the temperature is lower than 900°C, gaseous FeF ₃ may not be generated, and if the temperature is higher than 1300°C, many by-products may be generated. By controlling the calcination temperature, calcination time and the ratio of raw materials, high fluorination of iron ore or _{Fe2O3 -} containing minerals can be realized, and the purity of the prepared _FeF3 can be further improved. In order to further improve the purity of the final gaseous FeF ₃ , the solid FeF ₃ is gasified at a temperature of 1000 ° C to 1400 ° C. By gasifying the solid FeF ₃ within this temperature range, the final production can be effectively improved. The purity of the resulting gaseous FeF ₃ .

In another embodiment of the present invention, the fluoride may also be hydrofluoric acid, and the specific step of step 101 is preferably to uniformly mix iron ore or minerals containing Fe ₂ O ₃ and hydrofluoric acid to obtain a mixture. The mass percentage of hydrofluoric acid in the mixture is 20% to 90%. The mass concentration of hydrofluoric acid is 20% to 40%. In this way, iron ore or _Fe2O3 -containing minerals can be fully contacted with hydrofluoric acid, so that the reaction in _the subsequent process _is more complete, iron ore or _Fe2O3 -containing minerals can be highly fluorinated, and the production of FeF ₃ yields.

Since in this embodiment, iron ore or _{Fe2O3 -} containing minerals need to react with hydrofluoric acid, specifically, the specific steps of step 102 are preferably:

Step 10221: React the mixture at 100-200°C for 3h-15h to generate solid FeF ₃ .

Step 10222: heating solid FeF ₃ to 1000°C-1400°C for gasification to obtain gaseous FeF ₃ .

Controlling the reaction temperature and the reaction time within the above-mentioned range can make the reaction more complete and improve the yield of preparing gaseous FeF ₃ .

In addition, the iron ore mentioned in the present invention or the mineral _{containing Fe2O3} can be any of the following materials: bauxite, magnetite, hematite, limonite, siderite, Iron sulfide ore, iron silicate ore, waste containing Fe ₂ O ₃ . It should be noted that the raw materials used in the preparation method provided by the present invention, whether high-grade iron ore or _Fe2O3 -containing minerals are raw _materials , or low-grade iron ore or _{Fe2O3 -} containing Minerals are used as raw materials, and high-purity FeF ₃ can be prepared.

The following are _FeF provided by the invention The specific preparation example of the preparation method:

Preparation example 1: Preparation of high-purity FeF ₃ with hematite and NH ₄ F as raw materials

The hematite and NH ₄ F are uniformly mixed to obtain a mixture, and the average particle size of the hematite and NH ₄ F is less than 3 mm. The mass percentage of NH ₄ F in the mixture is 80%. The mixture is calcined at 900°C for 3 hours to generate a mixed gas of gaseous FeF ₃ and other gaseous substances, and the temperature of the mixed gas is lowered to below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances. The gas-solid mixture is separated to obtain solid FeF ₃ with high purity, and then the solid FeF ₃ is gasified at a gasification temperature of 1050°C to further obtain high-purity gas FeF ₃ . Since FeF ₃ is gaseous at high temperature, it escapes. The generated FeF ₃ passes through the high-temperature gas collection device, collection device, and purification device to obtain high-purity FeF ₃ . The reaction equation is as follows:

Fe ₂ O ₃ +6NH ₄ F→2FeF ₃ +6NH ₃ +3H ₂ O

Preparation example 2: Preparation of high-purity FeF ₃ from limonite and AlF ₃

Mix the limonite and AlF ₃ evenly to obtain a mixture, and the average particle size of the limonite and AlF ₃ is less than 3 mm. The mass percentage of _AlF3 in the mixture is 60%. The mixture is calcined at 800°C for 6 hours to generate a mixed gas of Al ₂ O ₃ , gaseous FeF ₃ and other gaseous substances, and the temperature of the mixed gas is lowered to below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances. The gas-solid mixture is separated to obtain solid FeF ₃ with high purity, and then the solid FeF ₃ is gasified at a gasification temperature of 1250°C to further obtain high-purity gas FeF ₃ . _FeF3 is gaseous at high temperature and escapes from solid. The generated FeF ₃ passes through a high-temperature gas collection device, a cooling device, and a purification device to obtain high-purity FeF ₃ . The reaction equation is as follows:

Fe ₂ O ₃ +2AlF ₃ ·3H ₂ O→Al ₂ O ₃ +2FeF ₃ +6H ₂ O

Preparation example 3: Preparation of high-purity FeF ₃ with siderite and NH ₄ HF ₂ as raw materials

Mix siderite and NH ₄ HF ₂ uniformly to obtain a mixture, and the average particle size of siderite and NH ₄ HF ₂ is about 3mm. The mass percentage of NH ₄ HF ₂ in the mixture is 40%. The mixture is calcined at 700°C for 5 hours to generate a mixed gas of gaseous FeF ₃ and other gaseous substances, and the temperature of the mixed gas is lowered to below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances. The gas-solid mixture is separated to obtain solid FeF ₃ with high purity, and then the FeF ₃ is gasified at a gasification temperature of 1350°C to further obtain high-purity gas FeF ₃ . _FeF3 is gaseous at high temperature and escapes from solid. The generated ferric trifluoride passes through a high-temperature gas collection device, a cooling device, and a purification device to obtain high-purity FeF ₃ . The reaction equation is as follows:

Fe ₂ O ₃ +3NH ₄ HF ₂ →2FeF ₃ +3NH ₃ +3H ₂ O

Preparation Example 4: Preparation of high-purity FeF ₃ with magnetite and NaF as raw materials

The magnetite and NaF are uniformly mixed to obtain a mixture, and the average particle diameter of the magnetite and NaF is about 2.8 mm. The mass percent of NaF in the mixture is 35%. The mixture is calcined at 1300°C for 15 hours to generate a mixed gas of NaOH, gaseous FeF ₃ and other gaseous substances, and the temperature of the mixed gas is lowered to below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances. The gas-solid mixture is separated to obtain FeF ₃ with high purity, and then the FeF ₃ is gasified at a gasification temperature of 1400°C to further obtain high-purity gaseous FeF ₃ . _FeF3 is gaseous at high temperature and escapes from solid. The generated FeF ₃ is passed through a high-temperature gas collection device, a cooling device, and a purification device to obtain high-purity FeF ₃ . The reaction equation is as follows:

Fe ₂ O ₃ +6NaF+3H ₂ O→2FeF ₃ +6NaOH

Preparation Example 5: Preparation of high-purity FeF ₃ from waste materials containing Fe ₂ O ₃ and CaF ₂

The waste material containing Fe ₂ O ₃ and CaF ₂ are uniformly mixed to obtain a mixture, and the average particle diameter of the waste material containing Fe ₂ O ₃ and CaF ₂ is less than 3mm. The mass percentage of _CaF in the mixture is 50%. The mixture is calcined at 1000°C for 10 hours to generate a mixed gas of CaO, gaseous _FeF3 and other gaseous substances, and the temperature of the mixed gas is lowered to below 800°C to obtain a gas-solid mixture of solid _FeF3 and other gaseous substances. The gas-solid mixture is separated to obtain solid FeF ₃ with high purity, and then the FeF ₃ is gasified at a gasification temperature of 1300°C to further obtain high-purity gas FeF ₃ . _FeF3 is gaseous at high temperature and escapes from solid. The generated FeF ₃ is passed through a high-temperature gas collection device, a cooling device, and a purification device to obtain high-purity FeF ₃ . The reaction equation is as follows:

Fe ₂ O ₃ +3CaF ₂ →2FeF ₃ +3CaO

The following table is the data comparison table of the data of each preparation example in the present invention and comparative example:

It can be seen from the above table that the preparation method of _FeF provided by the present invention has effects such as low cost, high quality, high yield, and high purity.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. _FeF The preparation method is characterized in that, comprises the steps: Mix iron ore and fluoride evenly to obtain a mixture; reacting the mixture to obtain gaseous FeF ₃ ; The fluoride is solid fluoride or hydrofluoric acid; When the fluoride is a solid fluoride, the step reacts the mixture to obtain gaseous FeF ₃ , which specifically includes the following steps: pressing the mixture into a billet; introducing air and calcining to obtain gaseous FeF ₃ and other A mixed gas of gaseous substances, wherein the calcination temperature is 900°C-1300°C, and the calcination time is 3h-15h; Cool the mixed gas below 800°C to obtain a gas-solid mixture of solid FeF ₃ and other gaseous substances; separate the gas-solid mixture to obtain solid FeF ₃ ; gasify the solid FeF ₃ to obtain gaseous _FeF3 ; When described fluoride is hydrofluoric acid, described step makes described mixture react, obtains gaseous state _{FeF The} concrete steps are: The mixture is reacted at 100°C to 200°C for 3h to 15h to generate solid FeF ₃ ; The solid FeF ₃ is heated to 1000°C-1400°C for gasification to obtain gaseous FeF ₃ . 2. FeF according to claim ₁ The preparation method is characterized in that, reacting the mixture, obtains gaseous FeF _The step also includes the following steps after the step: The gaseous FeF ₃ is collected, cooled and purified to obtain FeF ₃ with a purity of 99%-99.99%. 3. FeF according to claim ₂ The preparation method is characterized in that, said step mixes iron ore and fluoride homogeneously, obtains in the mixture, and described fluoride is any in the following solid fluoride: NaF, NH ₄ F, NH ₄ HF ₂ , CaF ₂ and AlF ₃ , the particle diameters of the iron ore and the solid fluoride are all less than 3mm. 4. FeF according to claim ₃ The preparation method is characterized in that, iron ore and fluoride are mixed uniformly in said step, and in the mixture obtained, the mass percent of said fluoride in said mixture is 20% to 90%. 5. The preparation method of FeF ₃ according to claim 1, characterized in that, in the gasification of the solid FeF ₃ to obtain gaseous FeF ₃ , the gasification temperature is 1000°C-1400°C. 6. FeF according to claim ₁ The preparation method is characterized in that, the fluoride is hydrofluoric acid, and the step is to mix the iron ore and the fluoride evenly, and the concrete steps for obtaining the mixture are: The iron ore and hydrofluoric acid are uniformly mixed to obtain a mixture, the mass percentage of the hydrofluoric acid in the mixture is 20%-90%; the mass concentration of the hydrofluoric acid is 20%-40%. 7. according to any one of claim 1-6 The preparation method of _FeF3 is characterized in that, the iron ore is any one of the following materials: bauxite, magnetite, hematite , limonite, siderite, iron sulfide ore, iron silicate ore.