RU2739040C1 - Method of producing ferrotungsten based on reduction of self-propagating gradient of aluminothermy and slag refining - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used in producing ferrotungsten by an aluminothermic self-propagating reduction gradient. Method involves separation of raw materials containing powder of tungsten and iron oxides and slag-forming components into several batches, placing first batch of raw materials into reaction furnace, igniting magnesium powder placed on raw materials for aluminothermic reduction with continuous addition of batches of raw materials until completion of reaction and obtaining high-temperature melt, or said raw materials are gradually placed in mixer at constant speed with gradual addition of aluminum powder, mixed raw materials are placed into a reaction furnace for aluminothermic reduction. Performing heat insulation melting by means of electromagnetic induction heating to obtain slag of base aluminum oxide of upper layer and alloyed melt of lower layer, method includes mixing and refining obtained doped melt of lower layer by blowing it with refined slag using carrier gas, melting melted high-temperature melt to room temperature.

EFFECT: invention increases rate of reduction of tungsten and iron from their oxides and reduces power consumption of the process.

10 cl, 12 ex

Description

Technical area

This invention relates to a method for producing ferrotungsten, which specifically relates to a method for producing ferrotungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag

State of the art

Ferrotungsten is one of the important ferroalloys in the steel industry, tungsten is the main element of alloy tool steel, which can greatly improve the wear resistance and machinability of steel. Tungsten, which forms carbides in steel, partially dissolves in iron and forms a solid solution. Tungsten can increase tempering resistance, redness, strength and wear resistance due to the formation of carbides in steel. It is mainly used for melting high speed steel, hot forging molds, etc. At present, the main methods for melting ferro-tungsten are sintering, iron removal and alumothermy. The sintering method uses an open electric furnace, which can be moved along a rail track, and is separated from the top of the furnace body, and carbon is used as a reducing agent. The raw materials are mainly refined tungsten ore, pitch coke (or petroleum coke) and slag-forming components (bauxite). The recovery rate of tungsten in this method is low. The iron removal method is suitable for melting ferro-tungsten containing 70% low melting point tungsten. Silicon and carbon are used as reducing agents, 75% ferrosilicon and a small amount of pitch coke (or petroleum coke) are used for smelting reduction. The recovery of tungsten is high, but the energy consumption of smelting is also high. The aluminothermic method uses secondary tungsten carbide and iron as raw materials, aluminum is used as a reducing agent, and the thermal energy of combustion of carbon and aluminum in tungsten carbide is used to convert tungsten and iron into ferro-tungsten raw materials, thereby saving a large amount of electrical energy and reducing costs. At the same time, since the impurities in the tungsten carbide of the raw material are much lower than the impurities of the tungsten concentrate, the product quality is higher than that of the ferro-tungsten, which is made from the tungsten concentrate. The recovery rate of tungsten is also higher than that of tungsten concentrate. However, this method is limited by the source of raw materials and is not suitable for mass production.

Based on the lack of a low rate of reduction of alloying elements, high energy consumption and limited raw material sources in the process of preparing ferrotungsten, this invention proposes a new method for producing ferrotungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag.

The essence of the invention

While addressing existing technical issues, the present invention provides one method for producing ferrotungsten based on self-propagating aluminothermy gradient recovery and slag refining, where WO ₃ , Fe ₂ O ₃ are used as feedstock. As a result of the reaction, a high-temperature melt is obtained, and the alkalinity and melting point of the slag are controlled by the addition of a high-alkalinity slag for the high-temperature melt, and the slag is washed and refined, and finally the slag is removed to obtain ferro-tungsten. The technical solution of this invention:

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) One of the following two methods is used to restore the self-propagating gradient of aluminothermy:

The first method: raw powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components are separated into several batches. The first batch of raw materials is placed in a reaction furnace, ignited magnesium powder from the top of the material causes a self-propagating reaction, continuously adding raw materials from other batches, until the reaction has completely reached the high-temperature melt. The aluminum content in each batch of raw materials gradually decreases from a gradient of 1.1 ~ 1.25 times to 0.9 ~ 0.75 by the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total aluminum content in the raw material is 0.95 ~ 1.00 of the theoretical stoichiometric ratio of the self-propagation reaction aluminothermy.

The second method: a mixture of raw material powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time, the aluminum powder is gradually placed into the raw material mixer using a uniform flow rate of gradual reduction, the mixed raw material is placed into a reaction furnace for carrying out the aluminothermy self-propagation reaction. There are no interruptions in the entire mixing and reaction process, until all raw materials reach the high-temperature melt after complete reaction.

Among them, the aluminum content in continuously supplied materials to the reaction furnace is reduced from 1.1-1.25 to 0.9-0.75 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction. The number n of gradient changes in the aluminum content in the entire process satisfies the equation: n = (bc) / a, where b denotes the highest aluminum content, c denotes the lowest aluminum content, and denotes the coefficient of the gradient change in the aluminum content, while 0 <a≤0.05 , the total amount of aluminum is 0.95-1.00 of the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy.

(2) By electromagnetic induction heating, thermal insulation smelting for the high-temperature melt takes place, thereby producing the upper level base alumina slag and the lower level alloyed melt.

(3) Refined slag is blown in the lower level for cleaning and refining the mixed slag.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

Further, the ratio of the mass of the raw powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components described in step (1) is 1.0: (0.2-0.49) :( 0.30-0.40 ) :( 0.07-0.39), grain size satisfies: grain size WO ₃ ≤2mm, grain size of Fe ₂ O ₃ powder ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm.

Further, the number of multiple batches described in step (1) is ≥4.

Further, the volume of the first batch described in step (1) is 10 ~ 30% of the total volume.

Further, the control parameter of the thermal insulation melting described in step (2): electromagnetic induction frequency ≥1000Hz, melting temperature 1700-1800⁰C, temperature holding time 5-15min.

Further, the refined slag is performed according to one of the following two methods (3): ① according to CaF ₂ at a weight ratio of 10-25%, the remainder of CaO; ② according to CaF ₂ with a mass ratio of 10-25%, Na ₂ O with a mass ratio of 5-10%, the remainder of CaO;

Further, the control parameter of mixed slag refining described in step (3): eccentric stirring is used, eccentricity 0.2 ~ 0.4, refined slag addition volume is 6-12% of the total raw material volume, purity ≥99.95% argon as carrier gas, eccentric stirring speed 50-150rpm, melting temperature 1700-1800⁰С, melting time 10-30min.

Further, the described ferro-tungsten is made according to the chemical composition at the weight percentage: W70.0-85.0%, Al≤2.0%, O≤1%, Fe residue.

The technical result of this invention:

1. This invention performs self-propagation of aluminothermy with the first batch of feedstock having a high aluminum content of the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, resulting in a high-temperature melt, which is favorable for subsequent reactions of feedstock with low aluminum content. At the same time, “first high aluminum then low” ensures that the melt is in a strong reducing atmosphere, thereby ensuring complete reduction of the metal oxide and gradually decreasing the aluminum ratio. The excess reductant in combination with the ferro-tungsten in the melt is gradually released and gradually reacts with the tungsten oxide in the subsequent low-aluminum feedstock added, thereby effectively reducing the aluminum residue in the final product. The more batches are added or the less the reduction in the aluminum gradient in the continuously added feed, the lower the residual aluminum fraction.

2. The present invention, by refining the mixed slag, controls the basicity and melting point of the added refined slag to effect a thorough chemical reaction of separating the metal from the slag, thereby effectively removing inclusions such as alumina; at the same time, the thermal heat treatment process fully exploits the thermal response of the system, which can significantly reduce the energy consumption in the production process. In addition, the present invention uses electromagnetic induction heating to perform thermal insulation smelting prior to mixing and refining the slag to form an upper alumina slag layer and a lower alloy melt layer, which can effectively enhance the metal-slag separation process.

3. Ferro-tungsten obtained by the present invention is made according to the chemical composition with the mass percentage: W70.0-85.0%, Al≤2.0%, O≤1%, Fe residue, where the tungsten content is high, the aluminum content is low, the properties are stable.

Specific methods of implementation

In the description of the present invention, it should be noted that in cases where specific conditions are not indicated in the examples, they are performed in accordance with the usual conditions or conditions recommended by the manufacturer. If the reagent or instrument used is not specified by the manufacturer, then this is a common product available on the market.

The present invention is described in more detail below in connection with specific examples of implementation, which are interpretations and not limitations of the invention.

Example implementation 1

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components is 1.0: 0.28: 0.33: 0.07, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size Fe2O3 powder ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; the raw material is divided into 5 batches, the aluminum ratio in each batch is 1.20, 1.05, 1.0, 0.90, 0.85 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total aluminum content in the raw material is 0.98 times the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the weight of the first batch of raw materials is 20% of the total weight of raw materials. The first batch of raw materials is placed in a reaction furnace, the ignited magnesium powder from the top of the material causes a self-propagation reaction, and raw materials from other batches are continuously added until the reaction has completely reached the high-temperature melt.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, melting temperature 1800⁰C, temperature maintenance time 15min, separation of metal from slag, thereby obtaining slags of base alumina oxide of the upper layer and alloyed melt of the lower layer ...

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag is composed according to the following mass ratio: 10% CaF ₂ , 90% CaO. Control parameter: the addition volume of refined slag is 6% of the total raw material volume, the purity is ≥99.95% of argon carrier gas, the eccentric stirring speed is 50rpm, the eccentricity is 0.21, the melting temperature is 1800⁰C, the melting time is 10min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 79.2%, Al 1.8%, O 0.8%, the remainder of Fe.

Implementation example 2

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO in 1.0: 0.29: 0.34: 0.15, respectively, their grain size satisfies: grain size WO ₃ , ≤2mm, grain size Fe2O3 powder ≤0.2mm, aluminum powder grain size ≤2mm, slag-forming component grain size ≤0.2mm, component grain size; the raw material is divided into 6 batches, the ratio of aluminum in each batch is 1.20, 1.1, 0.95, 0.90, 0.85, 0.80 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total aluminum content in the raw material is 0.97 times the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the weight of the first batch of raw materials is 28.6% of the total weight of raw materials. The first batch of raw materials is placed in a reaction furnace, the ignited magnesium powder from the top of the material causes a self-propagation reaction, and raw materials from other batches are continuously added until the reaction has completely reached the high-temperature melt.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1750 ℃, temperature maintenance time 10min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer ...

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag is composed according to the following mass ratio: 20% CaF ₂ , 80% CaO. Control parameter: the addition volume of refined slag is 8% of the total raw material volume, the purity is ≥99.95% of argon carrier gas, the eccentric stirring speed is 100rpm, the eccentricity is 0.33, the melting temperature is 1750⁰C, the melting time is 20min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 78.1%, Al 1.5%, O 0.72%, the remainder of Fe.

Implementation example 3

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO in 1.0: 0.32: 0.34: 0.35, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, powder grain size Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; raw materials are divided into 7 batches, the ratio of aluminum in each batch is 1.20, 1.1, 1.0, 0.95, 0.925, 0.90, 0.85 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total content aluminum in the raw material is 0.95 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, the weight of the first batch of raw materials is 22.2% of the total weight of the raw material. The first batch of raw materials is placed in a reaction furnace, the ignited magnesium powder from the top of the material causes a self-propagation reaction, and raw materials from other batches are continuously added until the reaction has completely reached the high-temperature melt.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1700 время, temperature maintenance time 5min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer.

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine the mixed slag, among which the refined slag is composed according to the following mass ratio: 25% CaF ₂ , 75% CaO. Control parameter: the addition volume of refined slag is 10% of the total raw material, the purity is ≥99.95% argon carrier gas, the eccentric stirring speed is 150rpm, the eccentricity is 0.4, the melting temperature is 1700 ℃, the melting time is 30min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 76.8%, Al 0.86%, O 0.51%, the remainder of Fe.

Implementation example 4

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.41: 0.36: 0.36, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; a mixture of raw material powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time aluminum powder is gradually placed into the raw material mixer using a uniform flow rate decreasing the graduation, the mixed raw material is placed into a reaction furnace to carrying out the reaction of self-propagation of aluminothermy. There are no interruptions in the entire mixing and reaction process, until all raw materials reach the high-temperature melt after complete reaction. Among them, the aluminum content in continuously supplied materials to the reaction furnace decreases from 1.22 to 0.76 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the gradient change coefficient a is 0.005. The number of gradient changes in the aluminum content in the whole process is 92 times, in addition, the total amount of aluminum is 0.98 times the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, melting temperature 1750 ℃, temperature maintenance time 10min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer ...

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag consists according to the following mass ratio: 10% CaF ₂ , 85% CaO, 5% Na ₂ O. Control parameter: refined slag addition volume is 6% of the total raw material, purity ≥99.95% argon carrier gas, eccentric stirring speed 100rpm, eccentricity 0.2, melting temperature 1750 ℃, melting time 20min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 75.4%, Al 1.6%, O 0.72%, the remainder of Fe.

Implementation example 5

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.43: 0.38: 0.28, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; a mixture of raw powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time, aluminum powder is gradually placed into the raw material mixer using a uniform flow rate of gradual reduction, the mixed raw material is placed into a reaction furnace to carrying out the reaction of self-propagation of aluminothermy. There are no interruptions in the entire mixing and reaction process, until all raw materials reach the high-temperature melt after complete reaction. Among them, the aluminum content in continuously supplied materials to the reaction furnace decreases from 1.21 to 0.76 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the gradient change coefficient a is 0.003. The number of gradient changes in the aluminum content in the whole process is 150 times, in addition, the total amount of aluminum is 0.97 times the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1700 ℃, temperature maintenance time 10min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer.

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag consists according to the following mass ratio: 10% CaF ₂ , 80% CaO, 10% Na2O ... Control parameter: the addition volume of refined slag is 8% of the total raw material, purity ≥99.95% argon carrier gas, eccentric stirring speed 100rpm, eccentricity 0.36, melting temperature 1700 ℃, melting time 20min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This example of the implementation of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 74.5%, Al 1.1%, O 0.43%, the remainder of Fe.

Implementation example 6

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of the powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.45: 0.38: 0.29, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; a mixture of raw powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time, aluminum powder is gradually placed into the raw material mixer using a uniform flow rate of gradual reduction, the mixed raw material is placed into a reaction furnace to carrying out the reaction of self-propagation of aluminothermy. There are no interruptions in the entire mixing and reaction process, until all the raw materials have reached the high-temperature melt after complete reaction. Among them, the aluminum content in continuously supplied materials into the reaction furnace decreases from 1.16 to 0.82 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the gradient change coefficient a is 0.001. The number of gradient changes in the aluminum content in the entire process is 340 times, in addition, the total amount of aluminum is 0.98 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, melting temperature 1700 ℃, temperature maintenance time 15min, separating the metal from the slag, thereby obtaining the slag of the base alumina of the upper layer and the alloyed melt of the lower layer ...

(3) After the fall of 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine the mixed slag, among which the refined slag consists according to the following mass ratio: 20% CaF ₂ , 75% CaO, 5% Na ₂ O. Control parameter: the addition volume of refined slag is 10% of the total raw material, the purity is ≥99.95% of argon carrier gas, the eccentric stirring speed is 100rpm, the eccentricity is 0.4, the melting temperature is 1750 ℃, the melting time is 30min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This example of the implementation of the manufacture and receipt of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 72.1%, Al 0.71%, O 0.36%, the remainder of Fe.

Implementation example 7

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.19: 0.30: 0.21, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; the raw material is divided into 5 batches, the ratio of aluminum in each batch is 1.20, 1.05, 1.0, 0.90, 0.85 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total aluminum content in the raw material is 0.975 times the theoretical stoichiometric ratio of the reaction of self-propagation of aluminothermy, the weight of the first batch of raw materials is 20% of the total weight of raw materials. The first batch of raw materials is placed in a reaction furnace, the ignited magnesium powder from the top of the material causes a self-propagation reaction, and raw materials from other batches are continuously added until the reaction has completely reached the high-temperature melt.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, melting temperature 1800 ℃, temperature maintenance time 15min, separating metal from slag, thereby obtaining slags of base alumina oxide of the upper layer and alloyed melt of the lower layer.

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag is composed according to the following mass ratio: 10% CaF ₂ , 90% CaO. Control parameter: the addition volume of refined slag is 6% of the total raw material, the purity is ≥99.95% argon carrier gas, the eccentric stirring speed is 50rpm, the eccentricity is 0.36, the melting temperature is 1800 ℃, the melting time is 10min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 84.1%, Al 1.68%, O 0.66%, the remainder of Fe.

Implementation example 8

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.22: 0.31: 0.16, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, powder grain size Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; the raw material is divided into 6 batches, the ratio of aluminum in each batch is 1.20, 1.1, 0.95, 0.90, 0.85, 0.80 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total aluminum content in the raw material is 0.965 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, the weight of the first batch of raw materials is 28.6% of the total weight of raw materials. The first batch of raw materials is placed in a reaction furnace, the ignited magnesium powder from the top of the material causes a self-propagation reaction, and raw materials from other batches are continuously added until the reaction has completely reached the high-temperature melt.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1750 ℃, temperature maintenance time 10min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer.

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag is composed according to the following mass ratio: 20% CaF ₂ , 80% CaO. Control parameter: the addition volume of refined slag is 8% of the total raw material, purity ≥99.95% argon carrier gas, eccentric stirring speed 100rpm, eccentricity 0.4, melting temperature 1750 ℃, melting time 20min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 83.5%, Al 1.2%, O 0.65%, the remainder of Fe.

Implementation example 9

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.27: 0.33: 0.18, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; raw material is divided into 7 batches, the ratio of aluminum in each batch is 1.20, 1.1, 1.0, 0.95, 0.925, 0.90, 0.85 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, in addition, the total aluminum content in the raw material is 0.95 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy, the weight of the first batch of raw materials is 22.2% of the total weight of the raw material. The first batch of raw materials is placed in a reaction furnace, ignited magnesium powder from the top of the material causes a self-propagation reaction, and raw materials from other batches are continuously added until the reaction completely reaches the high-temperature melt.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1700 ℃, temperature maintenance time 5min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer ...

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine the mixed slag, among which the refined slag is composed according to the following mass ratio: 25% CaF ₂ , 75% CaO. Control parameter: the addition volume of refined slag is 10% of the total raw material, the purity is ≥99.95% argon carrier gas, the eccentric stirring speed is 150rpm, the eccentricity is 0.32, the melting temperature is 1700, the melting time is 30min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 82.6%, Al 0.72%, O 0.32%, the remainder of Fe.

Implementation example 10

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.27: 0.33: 0.18, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; a mixture of raw powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time, aluminum powder is gradually placed into the raw material mixer using a uniform flow rate of gradual reduction, the mixed raw material is placed into a reaction furnace to carrying out the reaction of self-propagation of aluminothermy. There are no interruptions in the entire mixing and reaction process, until all raw materials reach the high-temperature melt after complete reaction. Among them, the aluminum content in continuously supplied materials to the reaction furnace decreases from 1.2 to 0.78 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the gradient change coefficient a is 0.003. The number of gradient changes in the aluminum content in the whole process is 140 times, in addition, the total amount of aluminum is 0.98 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1750 ℃, temperature maintenance time 10min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer.

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine the mixed slag, among which the refined slag consists according to the following mass ratio: 10% CaF ₂ , 85% CaO, 5% Na2O ... Control parameter: the addition volume of refined slag is 6% of the total raw material, the purity is ≥99.95% argon carrier gas, the eccentric stirring speed is 100rpm, the eccentricity is 0.38, the melting temperature is 1750 ℃, the melting time is 20min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at a percentage of the mass: W 81.3%, Al 1.43%, O 0.62%, the remainder of Fe.

Implementation example 11

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO is 1.0: 0.27: 0.33: 0.18, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, grain size of powder Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; a mixture of raw powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time, aluminum powder is gradually placed into the raw material mixer using a uniform flow rate of gradual reduction, the mixed raw material is placed into a reaction furnace to carrying out the reaction of self-propagation of aluminothermy. There are no interruptions in the entire mixing and reaction process, until all raw materials reach the high-temperature melt after complete reaction. Among them, the aluminum content in continuously supplied materials to the reaction furnace decreases from 1.19 to 0.77 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the gradient change coefficient a is 0.001. The number of gradient changes in the aluminum content in the entire process is 420 times, in addition, the total amount of aluminum is 0.96 times the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1700 ℃, temperature maintenance time 10min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer ...

(3) After falling 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine mixed slag, among which the refined slag consists according to the following mass ratio: 10% CaF ₂ , 80% CaO, 10% Na ₂ O. Control parameter: refined slag addition volume is 8% of total raw material, purity ≥99.95% argon carrier gas, eccentric stirring speed 100rpm, eccentricity 0.26, melting temperature 1700 ℃, melting time 20min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at the percentage of the mass: W 80.6%, Al 0.89%, O 0.38%, the remainder of Fe.

Implementation example 12

A method for producing ferro-tungsten based on the recovery of a self-propagating gradient of aluminothermy and refining of the slag includes the following steps:

(1) Reconstruction of the self-propagating gradient of aluminothermy

According to the dosage, when the ratio of the mass of powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components CaO in 1.0: 0.3: 0.34: 0.24, respectively, their grain size satisfies: grain size WO ₃ ≤2mm, powder grain size Fe ₂ O ₃ ≤0.2mm, grain size of aluminum powder ≤2mm, grain size of slag-forming components ≤0.2mm, grain size of components; a mixture of raw powder WO ₃ , Fe ₂ O ₃ and slag-forming components is gradually placed into the raw material mixer using a uniform flow rate, at the same time, aluminum powder is gradually placed into the raw material mixer using a uniform flow rate of gradual reduction, the mixed raw material is placed into a reaction furnace to carrying out the reaction of self-propagation of aluminothermy. There are no interruptions in the entire mixing and reaction process, until all raw materials reach the high-temperature melt after complete reaction. Among them, the aluminum content in the continuously fed materials into the reaction furnace decreases from 1.12 to 0.84 times the gradient using the theoretical stoichiometric ratio of the aluminothermy self-propagation reaction, the gradient change coefficient a is 0.0008. The number of gradient changes in the aluminum content in the entire process is 350 times, in addition, the total amount of aluminum is 0.96 times the theoretical stoichiometric ratio of the self-propagation reaction of aluminothermy.

(2) By heating electromagnetic induction, heat-insulating smelting occurs for a high-temperature melt: electromagnetic induction frequency ≥1000Hz, smelting temperature 1700 ℃, temperature maintenance time 15min, separating metal from slag, thereby obtaining slag of base alumina of the upper layer and alloyed melt of the lower layer.

(3) After the fall of 90% of the base alumina slag of the upper layer, refined slag is blown in the lower layer to clean and refine the mixed slag, among which the refined slag consists according to the following mass ratio: 20% CaF ₂ , 75% CaO, 5% Na ₂ O. Control parameter: the addition volume of refined slag is 10% of the total raw material volume, purity ≥99.95% argon carrier gas, eccentric stirring speed 100rpm, eccentricity 0.38, melting temperature 1750 ℃, melting time 30min.

(4) The melted high-temperature melt is cooled to room temperature, after removing the upper slag, ferro-tungsten is obtained.

This exemplary embodiment of the manufacture and production of ferro-tungsten is carried out according to the chemical composition at the percentage of the mass: W 78.4%, Al 0.68%, O 0.24%, the remainder of Fe.

It should be understood that for those of ordinary skill in the art, improvements and conversions can be made in accordance with the above description, all such improvements and conversions come under the protection of the present invention.

Claims (18)

1. A method of obtaining ferro-tungsten, characterized in that (1) carry out aluminothermal self-propagating gradient reduction of tungsten and iron from their oxides by preparing raw materials by separating raw materials containing WO ₃ , Fe ₂ O ₃ powder, aluminum powder and slag-forming components into several batches, placing the first batch of raw materials in a reaction furnace , ignition of the magnesium powder placed on top of the raw materials to carry out aluminothermal self-propagating gradient reduction with the continuous addition of batches of raw materials until the reaction is completed and a high-temperature melt is obtained, while the aluminum content in each batch of raw materials is gradually reduced from 1.1-1.25 to 0, 9-0.75 of the theoretically required stoichiometry for carrying out aluminothermal self-propagating gradient reduction, while the total aluminum content in raw materials is 0.95-1.00 of the theoretically required stoichiometry and for carrying out aluminothermic self-propagating gradient reduction; (2) performing heat-insulating smelting to obtain a high-temperature melt by electromagnetic induction heating to obtain a base alumina slag of the upper layer and an alloyed melt of the lower layer; (3) stirring and refining the obtained alloyed melt of the lower layer by blowing it with refined slag using a carrier gas; (4) cooling the smelted high-temperature melt to room temperature, and after removing the upper slag layer, ferrotungsten is obtained. 2. A method of obtaining ferro-tungsten, characterized in that (1) carry out aluminothermal self-propagating gradient reduction of tungsten and iron from their oxides by preparing raw materials containing powder WO ₃ , Fe ₂ O ₃ and slag-forming components, mixing until a mixture is obtained, which is gradually placed into a mixer at a constant speed, with the gradual addition of aluminum powder into the mixer at a uniform decrease in speed, the mixed raw materials are placed in a reaction furnace to carry out aluminothermal self-propagating gradient reduction, while the mixing process and the aluminothermal self-propagating gradient recovery process are carried out continuously until all raw materials reach the high-temperature melt after complete reaction, with this, the aluminum content in continuously supplied raw materials into the reaction furnace is reduced from 1.1-1.25 to 0.9-0.75 from the theoretically necessary stoichiometry for carrying out aluminothermic self-propagating gradient recovery, while the number n of gradient changes in the aluminum content in the entire process satisfies the equation: n = (bc) / a, where b is the highest aluminum content, c is the lowest aluminum content, and is the coefficient of the gradient change in the aluminum content, while 0 <a≤0.05, and the total amount of aluminum is 0.95-1.00 of the theoretical stoichiometry required for carrying out aluminothermal self-propagating gradient reduction; (2) performing heat-insulating smelting to obtain a high-temperature melt by electromagnetic induction heating to obtain a base alumina slag of the upper layer and an alloyed melt of the lower layer; (3) stirring and refining the obtained alloyed melt of the lower layer by blowing it with refined slag using a carrier gas; (4) cooling the smelted high-temperature melt to room temperature, and after removing the upper slag layer, ferrotungsten is obtained. 3. The method according to claim 1 or 2, in which the ratio of the mass of the powder WO ₃ , Fe ₂ O ₃ , aluminum powder and slag-forming components in step (1) is 1.0: (0.2-0.49) :( 0 , 30-0.40) :( 0.07-0.39), the grain size of the materials mentioned is: WO ₃ powder ≤2mm, Fe ₂ O ₃ powder ≤0.2mm, aluminum powder ≤2mm, slag-forming components ≤0.2mm ... 4. The method of claim 1, wherein the number of batches in step (1) is> 4. 5. The method according to claim 1, wherein the weight of the first batch of raw materials in step (1) is 10-30% of the total weight. 6. The method according to claim 1 or 2, in which step (2) is carried out at an electromagnetic induction frequency of ≥1000Hz, a melting temperature of 1700-1800 ° C and a melting time of 5-15min. 7. The method according to claim 1 or 2, in which the refined slag in step (3) has a composition, wt%: CaF ₂ 10-25, CaO is the rest. 8. The method according to claim 1 or 2, in which the refined slag in step (3) has the composition, wt%: CaF ₂ 10-25, Na ₂ O 5-10, CaO - the rest. 9. The method according to claim 1 or 2, in which in step (3) the following parameters of refining control are used: eccentric mixing is used, eccentricity is 0.2-0.4, the volume of refined slag addition is 6-12% of the total volume of raw materials , argon with a purity equal to or more than 99.95% is used as a carrier gas, the eccentric stirring speed is from 50 to 150 rpm, the refining temperature is 1700-1800 ° C, the melting time is 10-30 minutes. 10. The method according to claim 1 or 2, in which ferrotungsten contains, wt%: tungsten 70.0-85.0, aluminum 2.0 or less, oxygen 1.0 or less and iron the rest.