JP2000119759A - Dephosphorizing method for iron ore - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of performing the dephosphorization of iron ore under a mild condition of ordinary temp. and normal pressure with a simple device. SOLUTION: This method for the dephosphorization of the iron ore is performed by using a microorganism, Aspergillus sp. KSC-1004 strain or Fuzarium sp. KSC-1005 strain. The iron ore is preferably brought into contact with the microorganism in the presence of a treating lipid containing at least C, N, K, Mg, H and O source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for dephosphorizing iron ore using a microorganism.

[0002]

2. Description of the Related Art It has been known that phosphorus contained in iron ore migrates into iron ore using the same as a raw material and deteriorates steel quality. Dephosphorization in the iron making process is difficult to perform in a blast furnace, and is usually performed in a later steel making stage. Therefore, if phosphorus is contained in the iron ore, the load of the dephosphorization step in the steelmaking process increases, and the amount of slag generated, that is, the amount of industrial waste discharged, increases, and the productivity decreases significantly. For this reason, dephosphorization at the raw material stage has recently been regarded as important. However, phosphorus in the iron ore raw material is contained as an insoluble impurity in water, and it is inherently difficult to remove this by water washing or the like. Dephosphorization of hot metal is also being actively studied, but this requires out-of-pile equipment for treating hot metal at high temperatures.

On the other hand, the use of microorganisms is conventionally known as a method for treating phosphorus. This study has also been reported, for example, a method in which phosphorus contained in phosphate rock is solubilized by bacteria or fungi and lower phosphate rock is used as a fertilizer (Gaur AC et al .: Indi).
an J. of Exp. Biol., 11, 427 (1973)). It has also been reported that phosphorus in slag (non-metallic residue) discharged from the steel industry can be partially solubilized using Pseudomonas or Bacillus (MG Sardina et al.,
Biotechnology Letters (1986) 8: 247-252). However, it is not known to use microorganisms for dephosphorization of iron ore, which is a raw material for steel.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and provides a simple apparatus for dephosphorizing iron ore under mild conditions of normal temperature and normal pressure. It is intended to provide a method that can be performed using.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for dephosphorizing iron ore that can be carried out under mild conditions of normal temperature and normal pressure. Use or solubilize in water,
In particular, the present inventors have found a microorganism suitable for dephosphorization of iron ore, have found that the use of this microorganism can solve the above-mentioned problems, and have completed the present invention. Phosphorus in iron ore is solubilized by the action of direct metabolism of this microorganism or pH change.

That is, the method for dephosphorizing iron ore according to the present invention uses the microorganism Aspergillus sp.
p.) KSC-1004 strain or the microorganism Fusarium sp.
uzarium sp.) KSC-1005 strain. Note that sp. Is an abbreviation for species. In the present invention,
Iron ore and the microorganism Aspergillus sp.
llus sp.) KSC-1004 strain or the microorganism Fusarium sp.
The contact is preferably performed in the presence of a processing solution containing N, K, Mg, H, and O sources.

The treatment solution has a hydrogen ion concentration (pH) of 2
To 7 is preferable. When Aspergillus sp. KSC-1004 strain is used, it is preferable to use glycerol as a C, H, O source.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. The present invention relates to a method for dephosphorizing iron ore using a novel microorganism, and these microorganisms will be described first.

Microorganism The microorganism used in the present invention is Aspergillus sp. KSC-1004 strain or Fusarium sp. KSC-1005 strain. Mutants obtained by subjecting these to mutation treatment can also be used. As a method of the mutation treatment, a chemical mutation treatment method using a mutagen such as nitrosoguanidine (for example, Bio. Factors, Vol. 1, p. 297)
-302 (1988) and J. Gen. Microbiol, Vol. 135, p. 291
7-2929 (1989)) and an ultraviolet irradiation method.

[0010] This Aspergill sp.
us sp.) KSC-1004 strain and Fusarium sp.
ium sp.) KSC-1005 strain has the following bacteriological properties.
Both types were collected from the soil of Chiba City.

[0011] (Aspergillus SP
sp.) KSC-1004 strain) a. Morphological findings Slide culture was performed on a potato dextrose agar medium, and the mycelia, conidiophores, and conidial morphology and formation were observed with an optical microscope. It grows fast on potato dextrose agar medium and has a grayish green, wool-like surface. There is no production of soluble dye. From the microscopic observation of the slide culture (25 ° C, 7 days), the conidium head was columnar, the conidiophore was short, smooth wall, green, the top was a flask type,
Fialide grows directly in / 2 to 2/3. The conidium is spherical and there is no formation of the closed conch.

B. Culturing findings Table 1 shows the culturing properties on various agar plate media for fungi.

[0013]

C. Growth conditions Aspergillus sp.KSC-1004
The growth environment of the strain was investigated using a potato dextrose liquid medium. The results are shown below. Growth temperature range: 14-40 ° C Optimum growth temperature range: 29-33 ° C Best growth around 30 ° C Growth hydrogen ion concentration range: 2-11 Optimal growth hydrogen ion concentration range: 2.5-6.5 Hydrogen growth Best growth at ion concentration 3-4

D. Identification Based on the above bacteriological properties, the taxonomic position of this strain was identified as "Illustrated Genena of Perfect Funjay, 4th Edition (Illustrated genena ofimperfec
t fungi. 4th ed. Macmillan publishing company. II.
L.bamett and B.B.IIunter. 1987), the strain was found to be Aspergill sp.
us sp.). This strain is `` Aspergillus sp. KSC-1004 strain ''
July 1, 1997, Tsukuba City, Ibaraki Prefecture
No. 3 FERMP-1 in Institute of Biotechnology and Industrial Technology, National Institute of Advanced Industrial Science and Technology
It has been deposited as 6345.

(Fuzarium sp. KS)
C-1005 strain) a. Morphological Findings Plate cultivation was performed on a potato dextrose agar medium and a carnation leaf agar medium under fluorescent lamp irradiation conditions, and the mycelia, conidiophores and conidia morphology and formation were observed with an optical microscope. It grows rapidly on potato dextrose agar and has a white to pink surface. There is no production of soluble dye. Microscopic observation of culture (25 ° C, 3-7
Days), phialide formed spindle-shaped to sickle-shaped curved large conidia and one pear-spindle-shaped small conidia having one to several partition walls.

B. Identification Based on the above bacteriological properties, the taxonomic position of this strain was identified as "Illustrated Genena of Perfect Funjay, 4th Edition (Illustrated genena ofimperfec
t fungi. 4th ed. Macmillan publishing company. II.
L.bamett and B.B.IIunter. 1987) ", the strain was found to be Fusarium sp.
It was admitted to belong to. This strain was designated as Fusarium sp. KSC-1005 in July 1997.
It has been commissioned as FERM P-16346 by the Institute of Biotechnology and Industrial Technology, 1-3-1 Higashi, Tsukuba City, Ibaraki Prefecture on March 24.

(Culture method of microorganisms) C, N, K, Mg, H, O, S, P, Fe,
It preferably contains Ca and trace nutrients.
As the N source, those which can be used by these microorganisms, such as ammonium sulfate, ammonium nitrate, ammonium chloride and urea, can be used alone or in combination. It is preferable to add 1 to 10 g of these N sources to 1 liter of water. As the C, H, O sources, monosaccharides such as glucose, sucrose and starch, polysaccharides and alcohols such as methanol, ethanol and glycerin which can be used by these microorganisms can be used alone or in combination. The O source may be water or air. It is preferable to add 1 to 40 g of these C, H and O sources to 1 liter of water. Potassium monohydrogen phosphate, potassium dihydrogen phosphate, as S, K, Mg, P, Fe, Ca, etc.
Potassium nitrate, magnesium nitrate, ferrous nitrate, calcium chloride, magnesium sulfate and the like can be used alone or in combination. These salts are preferably added in an amount of 0.005 to 10 g per liter of water. Also F
e, S and the like may be contained in the yeast extract. As the water, distilled water, ion-exchanged water, tap water and the like can be used.

Using such a medium, a temperature of 15 to 40
C., preferably 25 to 35 ° C., pH 7.0 to 2.0, preferably 6.5 to 2.5, and the culture period is 1 to 7 days, preferably 2 to 4 days, and microbial cells are cultured. adjust. The pH of the medium is adjusted using inorganic acids (such as hydrochloric acid, nitric acid, and sulfuric acid) and organic acids. Organic acids include formic acid, acetic acid,
Saturated monocarboxylic acids such as propionic acid, butyric acid, and valeric acid; saturated dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, and malonic acid; acrylic acid, vinyl acetic acid, and fumaric acid Carboxylic acids such as carboxylic acid, maleic acid, etc., benzoic acid, o, m, p-benzenedicarboxylic acid, phenylacetic acid, phenoxyacetic acid, mandelic acid, etc .; glycolic acid, tartaric acid, lactic acid, malic acid, etc. And oxocarboxylic acids such as oxaloacetic acid, glyoxylic acid, pyruvic acid and levulinic acid, alkoxycarboxylic acids such as anisic acid, ascorbic acid and citric acid. These organic acids may be used alone or in combination of two or more.

Those skilled in the art can appropriately select the composition ratio of each component in the medium, the method of inoculating the cells with the medium, the amount, and the like according to the culture method. The method for culturing the microorganism is not particularly limited, and includes, for example, a known aeration culture method, a stirring culture method, or a stationary, shaking, or aeration agitation culture method, all of which are a batch fermentation method and a fed-batch batch fermentation method. , A repeated batch fermentation method, a continuous fermentation method, and the like.

This medium can be used as it is as a dephosphorization treatment solution. Also, the cells as dried cells, or
After mixing with pulverized coal, casein, skim milk, rice bran, and auxiliary agents that do not reduce the activity of microorganisms such as sawdust, the mixture can be dried, mixed with water or the like at the time of use, and used as a dephosphorization treatment liquid. In order to obtain dried cells, various methods such as a spray drying method and a freeze drying method which do not reduce the activity of the microorganism can be used. The spray drying method is inexpensive in terms of economy.

Method for Dephosphorizing Iron Ore In the present invention, the microorganism Aspergillus sp. KSC-1004 (hereinafter sometimes abbreviated as Aspergillus KSC-1004) or the microorganism Fusarium sp. ) Dephosphorization of iron ore using KSC-1005 strain (hereinafter sometimes abbreviated as Fusarium KSC-1005 strain). Aspergillus during dephosphorization
KSC-1004 strain and Fusarium KSC-1005 strain may be used in combination.

(Iron Ore) In the present invention, the type and shape of the iron ore to be dephosphorized are not particularly limited. For example, iron oxides such as magnetite, hematite, and maghemite, limonite (iron hydroxide) such as goethite and lecite, and siderite (iron carbonate)
And the like. Examples of the shape of the iron ore include lump ore, iron sand, and fine ore.

The production area is not particularly limited.
Iron ore from ewman, Karajas, Yandi, Riodose, Hamasley and other parts of the world can be processed without limitation. The phosphorus content of the iron ore raw material varies depending on the place of production and the like, but is usually 50 to 1000 ppm.
It is about. Iron ore, from the aspect of contact efficiency with microorganisms,
Usually, the particle size is about 4.75 mm or less, preferably 1.4 m.
It is subjected to a dephosphorization treatment in a size of about m or less.

In order to perform dephosphorization of iron ore using microorganisms, iron ore and the above microorganisms are mixed with at least C, N,
The contact is preferably performed in the presence of a processing solution containing K, Mg, H, and O sources. This contacting method is not particularly limited, but includes, for example, a method of spraying or spraying / circulating a treatment solution in which microorganisms are suspended, a method of spraying or scattering / circulating a treatment solution by adding microorganisms to iron ore, Examples include a method of immersing iron ore in a suspended treatment liquid, and a method of spraying and circulating a treatment liquid in which microorganisms are suspended in a treatment liquid in which iron ore is suspended. In the above, a part of the circulating fluid may be updated and used.

(Treatment liquid) The treatment liquid contains at least C, N,
Contains K, Mg, H, O sources. As the N source, ammonium sulfate, ammonium nitrate, ammonium chloride, urea and the like can be used alone or in combination. It is preferable to add 1 to 10 g of these N sources to 1 liter of water. As C, H, O sources, monosaccharides / polysaccharides such as glucose, sucrose, maltose, and starch, and alcohols such as methanol, ethanol, and glycerol can be used alone or in combination. The O source may be water or air. It is preferable to add 1 to 50 g of these C, H and O sources to 1 liter of water. As K and Mg, potassium nitrate, potassium chloride, magnesium sulfate, magnesium nitrate, magnesium chloride and the like can be used alone or in combination as salts. These salts are preferably added in an amount of 0.01 to 10 g per liter of water. As the water, distilled water, ion exchange water, tap water, and the like can be used.

The sources of Fe, Ca and S are not always necessary since they are obtained from iron ore. The phosphorus source is unnecessary because it is obtained from iron ore, and it is desirable that it is not contained in the processing solution.
The presence of phosphorus in the treatment liquid reduces the dephosphorization efficiency of iron ore. When Aspergillus strain KSC-1004 is used as the microorganism, glycerol is preferably used as the C, H, O source. By using glycerol, the number of cells increases easily, and the dephosphorization proceeds more. C,
The glycerol concentration in the treatment solution when glycerol is used as the H and O sources is usually 1 to 50 g / l as described above, but preferably 5 to 50 g / l to obtain a higher dephosphorization effect. Can be

The hydrogen ion concentration (pH) of the processing solution is 2 to 7
Is particularly preferable, and particularly preferably 2 to 4. When the pH is low, the dephosphorization rate is high, but the probability of death of the microorganism is high. When the pH is high, the dephosphorization rate becomes slow. The pH of the treatment liquid is adjusted using an inorganic acid (eg, hydrochloric acid, nitric acid, sulfuric acid) or an organic acid. In the iron ore after treatment, sulfur,
The acid used for pH adjustment is preferably an organic acid composed of carbon, oxygen, and hydrogen so as not to leave nitrogen and halogen components.

Examples of the organic acid include saturated monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid and valeric acid, and saturated dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid and malonic acid. Unsaturated carboxylic acids such as acrylic acid, vinyl acetic acid, fumaric acid, and maleic acid; aromatic carboxylic acids such as benzoic acid, o, m, p-benzenedicarboxylic acid, cinnamic acid, phenylacetic acid, phenoxyacetic acid, and mandelic acid; Preferred are hydroxycarboxylic acids such as glycolic acid, tartaric acid, lactic acid and malic acid, alkoxycarboxylic acids such as anisic acid, ascorbic acid, citric acid and the like. These organic acids may be used alone or in combination of two or more.

When the microorganism and the iron ore are brought into contact with each other in the presence of the treatment liquid as described above, the amount of these usually used is: treatment liquid: microorganism: iron ore = 100 liter: 0.1
10 to 10 kg: about 10 to 300 kg. When the treatment liquid or the treatment liquid in which microorganisms are suspended is brought into contact with iron ore while being circulated, the amount of the circulating liquid per 1 kg of iron ore is usually 10 to 1000 ml / min, although it depends on the shape of the treatment container. It should be about the degree. The number of contact days is usually 3 days or more at room temperature, preferably 14 to 28 days.
About a day.

In the present invention, the above-mentioned microorganism is used for dephosphorization of iron ore, that is, the microorganism Aspergillus sp. KSC-1004 and / or the microorganism used for removing phosphorus from iron ore. Fusarium sp. KSC-1005 strain is provided. It is also possible to provide an iron ore dephosphorizing agent containing the above microorganism. That is, the microorganism Aspergillus sp. KSC-1004 strain and / or the microorganism Fusarium sp. KSC-
An iron ore dephosphorizer containing 1005 strains is provided. The dephosphorizing agent may include a processing solution containing at least a C, N, K, Mg, H, O source. These element sources can be the same as those described above. In particular, Aspergillus strain KSC-1004 and a dephosphorizing agent containing 1 to 50 g / L, preferably 5 to 50 g / L of glycerol as a C, H, O source in the treatment solution exhibit a high dephosphorization effect. The pH of the dephosphorizing agent is 2 to 7, preferably 2 to 7.
4.

[0032]

EXAMPLES Next, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. (Microbial Aspergillus sp.
p.) Culture of KSC-1004 strain) Aspergillus sp.
spergillus sp.) KSC-1004 strain was added to the following medium (100 ml, using a 300 ml Erlenmeyer flask), and the mixture was added at 30 ° C. and 20 ml.
The cells were cultured at 0 rpm for 2 days. Next, 15 at 5000 rpm
Centrifuge for 5 minutes and remove Aspergillus sp.
gillus sp.) KSC-1004 strain was isolated and recovered.

(Microbial Fusarium sp.)
m sp.) Culture of KSC-1005 strain) Fusarium sp.
arium sp.) KSC-1005 strain was added to 100 ml of the following medium (using a 300 ml Erlenmeyer flask), and the mixture was added at 30 ° C. and 200 r.
Cultured for 2 days at pm. Next, centrifuge at 5,000 rpm for 15 minutes to obtain Fusarium sp.
KSC-1005 strain was separated and recovered.

In addition, Aspergis sp.
llus sp.) KSC-1004 strain and Fusarium sp.
m sp.) The composition of the medium in which the KSC-1005 strain was cultured is as follows. Glucose 20 g Methanol 3 ml Yeast extract 5 g Ammonium chloride 6 g Potassium monohydrogen phosphate 2.5 g Potassium dihydrogen phosphate 2.5 g Magnesium sulfate heptahydrate 1.25 g Iron sulfate 10 mg Calcium chloride 10 mg Distilled water 1 liter pH (adjusted with hydrochloric acid) 6) In the following examples, 0.2 g (in terms of dry cells) of the microorganism obtained above was suspended per 100 ml of the treatment liquid and used for dephosphorization.

(Dephosphorizer) In the following Examples and Comparative Examples, the dephosphorizer shown in FIG. 3 was used. The dephosphorizer is
A Buchner funnel 3 having a processing section for iron ore 1 at the top,
A container 4 provided separately below the Buchner funnel 3 for storing the processing liquid 2 discharged from the Buchner funnel 3, and circulating the processing liquid from the lower part of the container 4 to the upper part of the Buchner funnel 3 via the circulation pump 5. And a line 6 for spraying.

(Dephosphorization rate of iron ore) The phosphorus content in the iron ore was measured by a fluorescent X-ray method. The dephosphorization rate was defined by the following equation. Dephosphorization rate = [{(amount of phosphorus in iron ore before treatment)-(amount of phosphorus in iron ore after treatment)] / (amount of phosphorus in iron ore before treatment)] x 100 (weight) %)

Example 1 A treatment solution A (pH 3) having the following composition was prepared. Glucose (liquid) 10 g Ammonium nitrate 5 g Potassium nitrate 4 g Magnesium sulfate heptahydrate 0.5 g Water 1 liter The pH was adjusted with formic acid.

Iron ore (brand Hamasley, particle size 4.75 m)
m or less) 200 g was charged into the processing section of Buchner funnel 3, and Aspergillus sp.
400 ml of the treatment solution A in which the C-1004 strain was suspended was added at 23 ° C.
It was circulated and sprayed at a rate of 0.5 ml / min. FIG. 1 shows the results of measuring the change over time in the amount of phosphorus in iron ore.
Table 2 shows the dephosphorization rate after 28 days.

(Examples 2 to 5) A test was conducted in the same manner as in Example 1 except that the type of iron ore was changed, and the amount of phosphorus in the iron ore was measured. Table 2 shows the results of the dephosphorization rate after 28 days.

(Comparative Example 1) A test (treatment liquid pH 3) was carried out in the same manner as in Example 1 except that no microorganism was used, and the amount of phosphorus in iron ore was measured. The results are shown in FIG. The results after 28 days are shown in Table 2.

(Comparative Example 2) The amount of phosphorus in iron ore was measured by circulating only water, and there was no change after 28 days.

(Examples 6 to 9) A test was conducted in the same manner as in Example 1 except that the composition of the treatment solution and the pH of the treatment solution A were changed with formic acid, and the amount of phosphorus in the iron ore was measured. Table 2 shows the results. Treatment liquid B Glucose (liquid) 10 g Urea 5 g Potassium chloride 4 g Magnesium sulfate hexahydrate 1 g Calcium chloride dihydrate 0.1 g Water 1 liter The pH was adjusted with oxalic acid.

Treatment liquid C Glucose (liquid) 10 g Ammonium nitrate 5 g Potassium nitrate 4 g Magnesium nitrate hexahydrate 1 g Water 1 liter The pH was adjusted with formic acid.

Example 10 A test was carried out in the same manner as in Example 1 except that Fusarium sp. KSC-1005 was used instead of Aspergillus sp. KSC-1004. The phosphorus content in iron ore was measured. The results are shown in FIG. Table 2 shows the dephosphorization rate after 28 days.

(Examples 11 to 12) A test was conducted in the same manner as in Example 10 except that the type of iron ore was changed, and the amount of phosphorus in the iron ore was measured. Table 2 shows the results.

[0046] ^* 1 As: Aspergillus sp. KSC-1004 Fu: Fusarium sp. KSC-1005

(Examples 13 to 15) A test was conducted in the same manner as in Example 7 except that the same amount of glycerol, maltose, and potato starch was used instead of glucose in the treatment liquid C, and the amount of phosphorus in iron ore was measured. Was measured. The results are shown in FIG.
Table 3 shows the dephosphorization ratio of Example 13 after 28 days.

(Examples 16 to 20) A test was conducted in the same manner as in Example 13 except that the glycerol concentration was changed as shown in Table 3, and the amount of phosphorus in the iron ore was measured. Table 3 shows the results.

[0049] * Other components in the processing solution: ammonium nitrate 5 g potassium nitrate 4 g magnesium nitrate hexahydrate 1 g water 1 liter

In the above, the amount of phosphorus in each iron ore before treatment used in Examples and Comparative Examples was 0.1 to 0.04% by weight. Iron ore has a particle size range of 0.42 to 4.75 mm
Was used.

[0051]

According to the present invention, the dephosphorization of iron ore using a microorganism can be carried out under mild conditions. In particular, when Aspergillus sp. KSC-1004 strain is used as a microorganism and glycerol is used as a C, H, O source, the dephosphorization rate of iron ore is particularly excellent. As a result, dephosphorization from low-grade high-phosphate iron ore around the world becomes possible, and the load of the dephosphorization step in the steelmaking process can be greatly reduced. Further, the amount of slag generated is greatly reduced, and industrial waste can be reduced.

[Brief description of the drawings]

FIG. 1 is a graph showing changes over time in the dephosphorization rate of iron ore when a microorganism is used and when no microorganism is used (Examples 1, 10 and Comparative Example 1).

FIG. 2 is a diagram showing a change over time in the dephosphorization rate of iron ore when the C, H, and O sources are changed.

FIG. 3 is a view showing a dephosphorization apparatus used in an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron ore 2 Processing solution 3 Buchner funnel 4 Container 5 Circulation pump 6 Line

Claims (3)

[Claims] 1. The microorganism Aspergillus sp.
gillus sp.) A method for dephosphorizing iron ore, comprising using KSC-1004 strain. 2. The microorganism Fusarium sp.
sp.) A method for dephosphorizing iron ore, characterized by using KSC-1005 strain. 3. An iron ore and a microorganism Aspergillus sp. KSC-1004 strain or a microorganism Fusarium sp. KSC-1005 strain at least as a C, N, K, Mg, H, O source. Contacting in the presence of a treatment liquid containing: