JP2018043915A - Method of producing phosphorus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing phosphorus which can reduce energy cost and can remove antimony.SOLUTION: The method comprises: a blow-in step of, in a state where a gas in a furnace 10 is adjusted to a reducing gas by combustion of a carbon material 21 accumulated in the furnace 10, blowing a liquid phosphorus ingredient into the carbon material 21 in the furnace 10 thereby pyrolyzing the phosphorus ingredient to generate phosphorus and evaporating the phosphorus; and a recovery step of recovering the evaporated phosphorus from an exhaust gas of the furnace 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing phosphorus (yellow phosphorus) from a liquid phosphorus raw material such as phosphoric acid.

Phosphoric acid (H ₃ PO ₄ ) is produced by a wet method or a dry method. A technique relating to the production of phosphoric acid is described in Non-Patent Document 1. In the production of phosphoric acid by a dry method described in Non-Patent Document 1, phosphor ore is heated together with silicon and carbon by an electric furnace and decomposed at a high temperature of 1400 to 1500 ° C. This produces the intermediate yellow phosphorus (P ₄ ). From yellow phosphorus through phosphorous oxide (P ₂ O ₅ ), it is further reacted with water to produce the final product, dry phosphoric acid. The intermediate yellow phosphorus is also used as a raw material for phosphorus compounds (for example, phosphorus trichloride, phosphorus oxychloride, phosphorus sulfide, etc.).

  By repeating the process of heating yellow phosphorus in an electric furnace, yellow phosphorus can be purified and the purity of yellow phosphorus can be improved. However, since energy costs are a problem, the production and purification of yellow phosphorus using an electric furnace has not been performed in Japan. For this reason, yellow phosphorus is manufactured in a foreign country where energy costs are not a problem and is imported into Japan. Dry phosphoric acid is produced from imported yellow phosphorus.

  Dry phosphoric acid is used for semiconductor etching. In this case, if the content of antimony in phosphoric acid is large, there is a risk of causing contamination or the like. For this reason, in yellow phosphorus used as a raw material (intermediate) of dry phosphoric acid, it is desired to reduce the content of antimony.

  A technique for producing high-purity yellow phosphorus is described in Patent Document 1. In the method for producing phosphorus described in Patent Document 1, first, iodine oxide or an iodate compound is added to yellow phosphorus and heated to change arsenic in phosphorus to arsenic oxide. Thereafter, yellow phosphorus is heated to the boiling point of arsenic oxide or less and distilled to recover high purity phosphorus.

Japanese Patent Laid-Open No. 6-40710

Goichi Matsunaga et al., “Industrial use of phosphorus”, Journal of Biotechnology, Japan Society for Biotechnology, 2012, 90, 8, 477-480

  As described above, yellow phosphorus is produced by an electric furnace. The purity of the produced yellow phosphorus can be improved by repeating the process of heating in an electric furnace. However, since energy costs are a problem, it is difficult to implement industrially in Japan.

  According to the method for producing phosphorus described in Patent Document 1, arsenic in phosphorus can be removed. However, no consideration has been given to antimony.

  The objective of this invention is providing the manufacturing method of phosphorus which can reduce energy cost and can remove antimony.

  According to one embodiment of the present invention, a method for producing phosphorus includes a liquid in a carbonaceous material in the furnace in a state where the gas in the furnace is adjusted to a reducing gas by partial combustion of the carbonaceous material deposited in the furnace. And a recovery step of recovering the evaporated phosphorus from the exhaust gas of the furnace. .

  As the phosphorus raw material, a phosphorus raw material produced by reacting phosphorous iron and an acid can be employed. In this case, the acid is preferably an acid that thermally decomposes into hydrogen, oxygen, carbon monoxide, and nitrogen. Alternatively, phosphoric acid produced by a dry method or a wet method can be adopted as the phosphorus raw material.

  In the blowing step, the phosphorus raw material is preferably blown into a region of 300 to 600 ° C. of the carbonaceous material, and the phosphorus raw material is blown into a region of 300 to 420 ° C. of the carbonaceous material. Is preferred.

  In the method for producing phosphorus according to the present invention, a liquid phosphorus raw material is blown into a high-temperature carbon material in the furnace in a state where the gas in the furnace is adjusted to a reducing gas. Thereby, phosphorus (yellow phosphorus) is produced from the phosphorus raw material and evaporated. Also, the evaporated phosphorus is recovered from the furnace exhaust gas. Such a method for producing phosphorus according to the present invention does not use an electric furnace, so that the energy cost can be reduced. In addition, since antimony does not evaporate, high-purity phosphorus from which antimony has been removed can be recovered.

FIG. 1 is a cross-sectional view conceptually showing the structure and use state of a furnace used in the method for producing phosphorus according to the present embodiment. FIG. 2 is a cross-sectional view conceptually showing the structure and use state of a furnace when using a phosphorus raw material obtained from phosphorus iron.

  Hereinafter, an embodiment of the method for producing phosphorus of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view conceptually showing the structure and use state of a furnace used in the method for producing phosphorus according to the present embodiment. The furnace 10 shown in FIG. 1 is a shaft type cylindrical furnace. The furnace 10 has an opening 14, a primary tuyere 11, a secondary tuyere 12, a lance 13 and a discharge port (not shown).

  The opening 14 is located at the top of the furnace. The furnace gas is discharged through the opening 14 and the carbon material is charged. The lance 13 extends vertically. The primary tuyere 11 is installed below the middle part of the furnace 10. Through the primary tuyere 11, fuel (for example, natural gas) is blown into the furnace together with the combustion-supporting gas. The secondary tuyere 12 is installed above the middle part of the furnace 10. The phosphorus raw material is blown into the carbonaceous material in the furnace through at least one of the lance 13 and the secondary tuyere 12. Here, the combustion-supporting gas is a gas containing oxygen molecules. An outlet is installed at the bottom of the furnace. The molten slag is discharged through this discharge port.

  In the furnace 10 having such a configuration, the carbonaceous material 21 charged from the opening 14 is deposited. The carbon material 21 is a solid material that generates heat and carbon monoxide by partial combustion. Moreover, the carbonaceous material 21 has carbon as a main component. As the carbon material 21, for example, coke, charcoal, biomass, RDF, waste wood, waste pulp, and pulverized coal can be used. Here, “RDF” is an abbreviation for “Refuse Delivered Fuel” and means a carbonaceous material derived from waste. As long as it can be used in a furnace, the carbonaceous material may include a non-solid carbon material (for example, coal tar or pitch) or may include coal. A carbon material may be used individually by 1 type, and may mix and use multiple types by a predetermined ratio.

  Such a carbonaceous material 21 is burned while blowing a combustion-supporting gas from the primary tuyere 11. Due to the combustion heat of the carbonaceous material 21, the temperature in the furnace rises as it approaches the furnace bottom. Moreover, the carbonaceous material 21 falls with combustion. The furnace temperature in front of the secondary tuyere 12 is set to a predetermined temperature according to the amount of combustion-supporting gas blown and the amount of carbonaceous material introduced.

  In the lower part of the furnace 10, molten slag 22 is generated. Slag is obtained by discharging the molten slag 22 from the discharge port.

  Here, in a state where the carbon material 21 is deposited, carbon monoxide gas is generated by a partial oxidation reaction between the carbon material and oxygen molecules. Thereby, the gas in a furnace turns into a reducing gas. In a state where the gas in the furnace is a reducing gas, a liquid phosphorus raw material is blown into the carbonaceous material 21 from the lance 13 (see the thick arrow in FIG. 1). A liquid phosphorus raw material may be blown into the carbonaceous material 21 from the secondary tuyere 12. In short, a liquid phosphorus raw material can be blown into the carbonaceous material 21 from at least one of the lance 13 and the secondary tuyere 12. When the phosphorus raw material is blown from the secondary tuyere 12, it is not necessary to provide the lance 13 in the furnace 10.

The phosphorus raw material is a raw material containing phosphoric acid. As the phosphorus raw material, for example, phosphoric acid produced by a wet method or a dry method can be employed. Since phosphoric acid (H ₃ PO ₄ ) is thermally decomposed at 213 ° C., when the phosphorus raw material is blown into the high-temperature carbonaceous material 21, phosphoric acid as a main component of the phosphorus raw material is thermally decomposed. Thereby, phosphorus (yellow phosphorus) is generated. Since yellow phosphorus evaporates at 280.5 ° C., the produced phosphorus evaporates, and the evaporated phosphorus is discharged from the opening 14 together with the gas in the furnace (see the shaded arrows in FIG. 1). As described above, since the gas in the furnace is adjusted to a reducing gas, oxidation of phosphorus can be prevented.

  Phosphorus (yellow phosphorus) is recovered from the furnace exhaust gas discharged from the opening 14. The phosphorus may be recovered by spraying water on the exhaust gas with, for example, a venturi scrubber and recovering the water. Thereby, phosphorus can be collected in a state stored in water.

  In such a manufacturing method of this embodiment, without using an electric furnace, the phosphorus raw material is pyrolyzed by the combustion heat of the carbonaceous material to generate phosphorus and evaporate it. For this reason, the manufacturing method of this embodiment can reduce energy cost significantly.

  Arsenic evaporates at 615 ° C. The temperature drops in the upper part of the furnace, and the deposited carbon material functions as a filter and captures arsenic. For this reason, if a phosphorus raw material is blown into an area of 600 ° C. or less in the deposited carbonaceous material, arsenic contained in the phosphorus raw material is captured by the carbonaceous material before evaporating. During regular repairs of the furnace, the charcoal is discarded and arsenic is also removed. In other words, arsenic is removed from the recovered (manufactured) phosphorus (yellow phosphorus). For this reason, the manufacturing method of this embodiment can manufacture high purity phosphorus.

  Antimony evaporates at 1587 ° C or higher. Due to the same mechanism as arsenic described above, the temperature drops in the upper part of the furnace, and antimony is trapped by the carbonaceous material in the furnace. In other words, antimony is removed from the recovered (manufactured) phosphorus (yellow phosphorus). For this reason, the manufacturing method of this embodiment can manufacture high purity phosphorus. That is, the recovered (manufactured) phosphorus (yellow phosphorus) removes not only antimony but also arsenic. Therefore, it is preferable that the phosphorus raw material is blown into a region of 600 ° C. or lower among the carbonaceous materials.

  Sulfur evaporates at 444 ° C. Moreover, the deposited carbon material functions as a filter and captures sulfur. For this reason, if phosphorus raw material is blown into an area of 420 ° C. or less among the carbonaceous materials, even if sulfur is generated by thermal decomposition of sulfate contained in the phosphorus raw material, it is captured by the carbonaceous material before the sulfur evaporates. Is done. Therefore, sulfur reaches the slag layer together with the carbonaceous material without evaporating. In other words, antimony, arsenic and sulfur are all removed from the recovered (manufactured) phosphorus (yellow phosphorus). Therefore, it is more preferable that the phosphorus raw material is blown into a region of 420 ° C. or lower among the carbonaceous materials.

  On the other hand, if the temperature of the region where the phosphorus raw material is blown is too low, phosphorus produced by thermal decomposition from the phosphorus raw material is trapped by the carbonaceous material before evaporating, and the amount of phosphorus recovered may be reduced. If the temperature of the region where the phosphorus raw material is blown is 300 ° C. or higher, most of the generated phosphorus evaporates before being captured by the carbonaceous material, so that the amount of phosphorus recovered can be secured. For this reason, it is preferable to inject | pour phosphorus raw material into the area | region of 300 degreeC or more among carbonaceous materials.

  Here, the temperature of the region where the phosphorus raw material is blown is the furnace temperature at the lower end position of the lance. For this reason, the temperature of the area | region which blows in phosphorus raw material can be adjusted by changing the height of the lower end position of a lance. Specifically, when the height of the lower end position of the lance is set high, the temperature of the space into which the phosphorus raw material is blown decreases. On the other hand, if the height of the lower end position of the lance is set low, the temperature of the space into which the phosphorus raw material is blown rises.

  The furnace 10 may be a converter type cylindrical furnace as shown in FIG. Alternatively, a blast furnace type cylindrical furnace may be used. These furnaces are cylindrical and have an opening at the top of the furnace. The furnace also has tuyere for blowing combustion-supporting gas into the carbonaceous material in the furnace and a lance for blowing phosphorus raw material into the carbonaceous material in the furnace. The furnace is not particularly limited in terms of shape and size, and may be a furnace having a capacity of about 10 t, or a large capacity furnace exceeding 200 t.

  In order to ensure the fluidity of the slag, the furnace 10 may be charged with limestone instead of a part of the carbonaceous material.

  In the above-described embodiment, the phosphorus raw material is phosphoric acid by a dry method or a wet method, but a phosphorus raw material may be obtained from phosphorus iron. Hereinafter, embodiments using a phosphorus raw material obtained from phosphorous iron will be described with reference to the drawings. Note that description of matters common to the embodiment shown in FIG. 1 is omitted as appropriate.

  FIG. 2 is a cross-sectional view conceptually showing the structure and use state of a furnace when using a phosphorus raw material obtained from phosphorus iron. The furnace 10 shown in FIG. 2 has the same basic structure as the furnace 10 shown in FIG. 1, and further has a tap (not shown). The tap is installed at the bottom of the furnace. Molten iron is discharged through this tap. In this case, the drainage port is installed at a position higher than the hot water outlet.

  As the phosphorus material, a phosphorus material produced by reacting phosphorous iron with an acid is used. The acid is, for example, sulfuric acid, oxalic acid or nitric acid. Here, the main components of phosphorous iron are Fe, P, and Mn. For this reason, a phosphorus raw material contains Fe and Mn with phosphoric acid.

  When a liquid phosphorus raw material is blown into the carbonaceous material from the lance 13 in a state where the gas in the furnace is a reducing gas (see the thick arrow in FIG. 2), phosphorus (yellow phosphorus) is generated by thermal decomposition. The generated phosphorus evaporates, and the evaporated phosphorus is discharged from the opening 14 together with the gas in the furnace (see the hatched arrows in FIG. 2). Phosphorus (yellow phosphorus) is recovered from the furnace exhaust gas discharged from the opening 14.

  Fe and Mn contained in the phosphorus raw material fall together with the carbonaceous material. In the process, Fe and Mn are heated and melted by the combustion heat of the carbonaceous material, and molten iron 23 containing Mn is generated. As a result, a molten iron layer containing Mn is formed on the furnace bottom, and a molten slag layer is formed on the molten iron layer. Manganese alloy iron (ferromanganese) can be obtained by discharging molten iron from the tap.

  Thus, even when using a phosphorus raw material obtained from phosphorus iron, phosphorus (yellow phosphorus) can be produced. In this case, manganese-based alloy iron (ferromanganese) is further obtained as a by-product.

  When using the phosphorus raw material obtained from phosphorous iron, a phosphorus raw material produces | generates by making phosphoric iron and an acid react. In that case, it is preferable to use an acid which thermally decomposes into hydrogen, oxygen and nitrogen. More specifically, it is preferable to use an organic acid such as oxalic acid or nitric acid. This is because, when obtaining a phosphorus raw material from phosphorous iron, if sulfuric acid is used, the S (sulfur) content of the molten iron increases and a step of removing the S occurs.

  In order to verify the effect of the phosphorus production method of the present invention, the following test was conducted.

[Test using phosphorus raw material derived from phosphorus iron]
In this test, the shaft type cylindrical furnace shown in FIG. 2 was used. The dimensions of the furnace 10 were a diameter of 1.5 m, a height from the furnace bottom to the furnace top of 3.8 m, and an internal volume of 6.0 m ³ . On the side wall of the furnace 10, four primary tuyere 11 are provided at 90 ° intervals at a height of 0.8m from the furnace bottom, and at 90 ° intervals at a height of 1.2m from the furnace bottom. Four secondary tuyere 12 were provided. Further, on the side wall of the furnace 10, one hot water outlet was provided at the furnace bottom, and one drainage outlet was provided at a position 0.73m above the furnace bottom. One lance 13 for injecting phosphorus raw material was provided. The height of the lower end position of the lance 13 was 1.6 m from the furnace bottom.

  Carbon material was charged into such a furnace 21 so that the height from the furnace bottom was approximately 3.6 m. At that time, in order to ensure the fluidity of the slag, limestone was charged together with the carbonaceous material. A phosphorus raw material was blown from the lance 13 in a state where the gas in the furnace was adjusted to a reducing gas by burning the carbonaceous material.

  Coke was used as a charcoal material. The amount of limestone charged was adjusted so that the basicity of the slag was 0.9 to 1.4. As a phosphorus raw material, what dissolved iron iron in the oxalic acid was used. Phosphorus iron contains, by mass, P: 23-28%, Si: 1%, C: 1%, S: 0.01%, Mn: 10% and Ti: 1%, the balance being Fe and impurities Met.

  From the primary tuyere 11, natural gas of fuel was blown together with oxygen as a combustion-supporting gas. The furnace temperature at the height of the lower end position of the lance 13 was controlled to 420 ± 10 ° C. (410 to 430 ° C.) by adjusting the blowing amount of these combustion-supporting gases and fuel. Moreover, the furnace temperature at the height position of the furnace top was controlled to 300 ± 10 ° C. (290 to 310 ° C.) by adjusting the charging height of the carbonaceous material.

  By supplying exhaust gas from the opening 14 at the top of the furnace to the venturi scrubber, phosphorus (yellow phosphorus) was recovered from the exhaust gas. Moreover, the molten iron 23 produced | generated in the lower part of a furnace was discharged | emitted from the tap, and it adjusted to the predetermined particle size by the water granulation. The molten slag 22 generated in the lower part of the furnace was discharged from the discharge port and adjusted to a predetermined particle size by water granulation.

The amount of carbonaceous material (coke) charged was 70 kg per ton of molten iron. The amount of oxygen blown from the primary tuyere was 362 Nm ³ per ton of molten iron. The amount of fuel injected from the primary tuyere was 170 kg per ton of molten iron.

About 250 kg of phosphorus could be recovered per 1 ton of phosphorous iron. The recovered phosphorus (yellow phosphorus) was extremely pure. Among the impurities contained therein, the concentration of antimony was 100 ppb, the concentration of arsenic was 10 ppb, and the concentration of sulfide ions was 50 ppb or less. The representative composition of the obtained manganese-based alloy iron was mass%, Fe: 80% and Mn: 13%, and the S content was 0.025 mass%. The resulting representative composition of the slag, in _{mass%, CaO: 38%, SiO} 2: 30% (CaO / SiO 2 = 1.27) and _Al 2 _O 3: 5%, _an, P 2 _{O 5} content The amount was 0% by mass.

  From these, it has been clarified that the manufacturing method of the present embodiment can manufacture extremely high purity phosphorus (yellow phosphorus) from a phosphorus raw material derived from phosphorus iron without using an electric furnace.

[Test using crude phosphoric acid as phosphorus raw material]
In this test, crude phosphoric acid was used as a phosphorus raw material. The crude phosphoric acid had a phosphoric acid concentration of 85% by mass, an antimony concentration of 4 ppm, an arsenic concentration of 40 ppm, and a sulfide ion concentration of 40 ppm.

  In this test, the shaft type cylindrical furnace shown in FIG. 1 was used. The dimensions of the furnace, the arrangement of the primary tuyere 11, the arrangement of the secondary tuyere 12, and the arrangement of the lance 13 were the same as those described above [Test using phosphorus raw material derived from phosphorus iron]. In the furnace 10 of this test, a discharge port was provided at the bottom of the furnace without providing a hot water outlet.

  The carbon material, limestone, combustion-supporting gas, and fuel were the same as those described in the above [Test using phosphorus raw material derived from phosphorus iron]. The furnace temperature at the height position of the lower end of the lance 13 was controlled to 420 ± 10 ° C. (410 to 430 ° C.) by adjusting the amount of blown gas and fuel. Moreover, the furnace temperature at the height position of the furnace top was controlled to 300 ± 10 ° C. (290 to 310 ° C.) by changing the charging height of the carbonaceous material.

The amount of carbonaceous material (coke) charged was 70 kg per ton of phosphorus recovered. The amount of oxygen blown from the primary tuyere was 362 Nm ³ per ton of phosphorus recovered. The amount of fuel injected from the primary tuyere was 170 kg per ton of phosphorus recovered.

  About 850 kg of phosphorus could be recovered per 1 ton of phosphorus material used. The recovered phosphorus (yellow phosphorus) was extremely pure. The impurities contained therein were antimony concentration of 100 ppb, arsenic concentration of 10 ppb, and sulfide ion concentration of 50 ppb or less.

  From these, it became clear that phosphorus (yellow phosphorus) can be manufactured from dry phosphoric acid by the manufacturing method of this embodiment, without using an electric furnace. Further, it was confirmed that antimony could be removed by the production method of the present embodiment, and it was confirmed that arsenic and sulfur could be further removed if a phosphorus raw material was blown into an area of 420 ° C. or lower among the carbonaceous materials in the furnace.

  According to the method for producing phosphorus of the present embodiment, energy costs can be reduced and high-purity phosphorus can be recovered. For this reason, the manufacturing method of this embodiment can be effectively used for manufacturing phosphorus (yellow phosphorus).

10 Furnace 11 Primary tuyere 12 Secondary tuyere 13 Lance 14 Opening 21 Carbon material 22 Molten slag (layer)
23 Molten iron (layer)

Claims (5)

A method for producing phosphorus,
The phosphorus raw material is pyrolyzed by injecting liquid phosphorus raw material into the carbonaceous material in the furnace while the gas in the furnace is adjusted to a reducing gas by combustion of the carbonaceous material deposited in the furnace. Generating phosphorus and evaporating the phosphorus;
A recovery step of recovering the evaporated phosphorus from the exhaust gas of the furnace. A method for producing phosphorus according to claim 1,
The phosphorus raw material is produced by dissolving phosphorous iron in an acid,
The said acid is a manufacturing method of phosphorus which is an acid thermally decomposed into hydrogen, oxygen, carbon monoxide, and nitrogen. A method for producing phosphorus according to claim 1,
The said phosphorus raw material is the manufacturing method of phosphorus which is the crude phosphoric acid manufactured by the dry method or the wet method. A method for producing phosphorus according to claim 1 or 2,
In the blowing step, the phosphorus raw material is blown into a region of 290 to 610 ° C. of the carbonaceous material. A method for producing phosphorus according to claim 1 or 2,
In the blowing step, the phosphorus raw material is blown into a region of 290 to 430 ° C. of the carbonaceous material.

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