JPH06116658A - High quality method of goethite iron ore for sinter - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a high-grade process for reducing phosphorus and alumina in goethite-containing iron ore and utilizing it as a raw material for pig iron production. [Structure] Goethite iron ore powder containing 2.4% or more of bound water, or fine powder part of goethite iron ore containing 1 mm or less thereof is heated to 500 ° C. or more and 1200 ° C. or less, and 1 normality (N) This is a method for improving the quality of a goethite-containing iron ore, which is brought into contact with the sulfuric acid or hydrochloric acid aqueous solution to elute impurities. [Effect] In addition to using high phosphorus-containing goethite iron ore powder as a sintering raw material, it is also possible to use waste liquid.
Effective use of resources and cost reduction can be achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving the quality of raw materials used in a blast furnace ironmaking process by reducing phosphorus and alumina in a goethite iron ore.

[0002]

2. Description of the Related Art In the blast furnace ironmaking method, phosphorus in the raw material remains in the hot metal. Therefore, we try not to use high phosphorus iron ore as much as possible. On the other hand, the alumina in the raw material is
It is not reduced in the blast furnace and becomes slag. If the amount of slag is large, the air permeability in the lower part of the blast furnace deteriorates and it becomes difficult to maintain stable operation of the blast furnace. Therefore, it is desirable that the amount of alumina in the raw material is small.

Therefore, in particular, the high-phosphorus iron deposit remains in the vicinity of the present mining mine and is left unattended. Looking at the world's iron ore resources, the high-quality hematite (Fe ₂ O ₃ ) ores that have been produced up to now are in the direction of depletion, and the development of new ore deposits is underway. Therefore, if this high phosphorus deposit can be used, it has great economic significance.

[0004]

[Problems to be Solved by the Invention] In the process of forming an iron deposit, phosphorus and alumina are formed as extremely fine particles,
It is generally precipitated in the goethite (Fe ₂ O ₃ .H ₂ O) part. That is, they are surrounded by game sites.

Further, the goethite part in iron ore is extremely dense, and the phosphorus content is a carcass of an animal, that is, a bone component, so that it is extremely stable. Therefore, even if the iron ore is treated with acid, it is extremely difficult to reduce phosphorus and alumina.

The present invention has been made in view of the above problems, and provides a method for enhancing the quality of goethite iron ore containing iron, which utilizes high phosphorus iron ore powder or the like.

[0007]

The inventor of the present invention has previously found that the goethite part decomposes at around 250 ° C., and a large number of cracks are generated along with the decomposition to become porous. Therefore, the present inventors invented the present method of pre-heating and then pickling treatment, by studying the conditions for promoting the removal of impurities in goethite ores containing this phenomenon of porosity and the change in heating of phosphorus compounds.

That is, the present invention is, among the sintering raw materials for blast furnace,
Goethite-containing (Fe ₂ O) containing 2.4% or more of bound water
₃・ H ₂ O) Iron ore powder is heated to 500 ° C. or higher and 1200 ° C. or lower, and is then contacted with sulfuric acid or hydrochloric acid aqueous solution of 1 normality (N) or higher to elute impurities, and for sinter ore This is a method for improving the quality of goethite-containing iron ore.

Further, in the above-described high-grade process, the goethite iron ore powder containing fine particles of goethite iron ore containing 1 mm or less is used.

Further, in each of the above-mentioned high-quality methods, the acid treatment waste solution of the sulfuric acid or hydrochloric acid aqueous solution in which impurities are eluted is reused as a raw material for producing ferrite powder.

[0011]

The operation and the process of the invention will be described in detail below.

The first feature of the method of the present invention is that the optimum conditions for acid elution of phosphorus and alumina are defined. As the iron ore, the Hamasley ore (Brockman iron ore formation) in Australia, which is adjacent to high and low phosphorus deposits, was selected as a representative.

The bound water in the powder ore (10 mm or less) is 2.4.
The iron content was 62 to 63% and the alumina content was 2.0 to 2.3%. Phosphorus content was 0.06% in low phosphorus mines and 0,6 in high phosphorus deposits.
It was 15%.

First, the decomposition start temperature of goethite was investigated,
It was confirmed to start from 210 ° C. There 300 ° C
Heat treatment every 100 ° C, for example, up to 20
The temperature is rapidly raised at 0 ° C./min, and after reaching a predetermined temperature, it is left to cool in the atmosphere.

Next, pure water was added to sulfuric acid (milliliter) having a molecular weight / (2.density) to make 1 liter, that is, 1N sulfuric acid, or pure water was added to hydrochloric acid (milliliter) having a molecular weight / density. It was put in a hydrochloric acid solution of 1 liter and taken out after 30 minutes, and iron ore was analyzed.

The results are shown in FIG. From this, it can be said that the proper temperature is 500 ° C to 1200 ° C, and the more preferable temperature is 800 to 1200 ° C. It is considered that such an appropriate range is achieved because decomposition of the phosphorus compound does not occur at 500 ° C or lower and densification of the goethite part occurs at 1200 ° C or higher.

Further, the same test is conducted on ores (bound water: 5-7%) and pisolite ores (6-10%) from the Maramanba iron ore formation having more bound water, that is, more goethite. , 500-1200 ° C was confirmed to be in the proper temperature range. Further, the longer the immersion time in the acid aqueous solution, the more the amount of impurities eluted, and it was almost saturated in 1 hour, but the appropriate temperature range did not change.

Next, the proper concentration was investigated by changing the acid concentration from 0.5N to 5N in 0.5N increments. Representative results are also shown in FIG. Although the elution amount of impurities increased as the acid concentration increased, the reduction of phosphorus content at 0.5N was slight, and it was found that it was necessary to make it 1N or more. Therefore, this is the reason why the present invention limits the normality to 1 or more.

As for the powdered ore for sinter in recent years, the hematite deposit has been depleted as described above, and thus the content of goethite-containing iron ore has been increasing. The amount can be huge. When the phosphorus content and the alumina content were examined according to the particle size, the goethite part was brittle and was easily pulverized, and the tendency was higher in the trickle part.

As shown in Table 1, it can be seen that when the particles are classified by 1 mm, the impurities are concentrated in fine powder of 1 mm or less. Further, in Table 1, the phosphorus content of 0.
A comparison was made between the case where 062% of iron ore (-10 mm) was directly treated by the method of the present invention and the case where it was classified by 1 mm and treated under the sieve. In addition, Table 1 shows the results of upgrading the quality of iron ore with a 1N sulfuric acid aqueous solution.

Here, the preheating temperature is 1000 ° C.
The 1 / N sulfuric acid aqueous solution was used, and the mass ratio of the ore / acid aqueous solution was 1. From Table 1, it is clear that when the fine powder of 1 mm or less is treated by the method of the present invention, the phosphorus content becomes the same as that after the whole treatment of the powder ore, and the dephosphorization rate is improved. This is the reason why the above-mentioned treatment is applied to the fine powder portion of 1 mm or less in the present invention.

[0022]

[Table 1]

On the other hand, it is well known that a ferrite powder as a magnetic material or a pigment is produced from a solution obtained by pickling a steel sheet at an iron mill. It was confirmed that the waste liquid after this treatment contained iron ions in an amount of 200 to 2000 ppm and could be sufficiently used as a raw material for the production of general ferrite powder.

[0024]

EXAMPLES The effects of the present invention will be described below with reference to examples.

As Example 1: Table 2 shows the results of upgrading the quality of the goethite ore according to the present invention. Phosphorus in the case of treating a typical goethite ore containing 2.4% or more of bound water is The amount of reduction of alumina is shown. 50% by the method of the present invention
The above phosphorus removal is possible. Alumina is also missing as much as the reduced amount of phosphorus.

[0026]

[Table 2]

As Example 2: Table 3 shows 1 m of the ore of Table 2
The quality improvement result of processing the goethite ore in the portion of m or less by the method of the present invention is shown. It is clear that the removal rate of phosphorus and alumina increases when the thickness is 1 mm or less.

[0028]

[Table 3]

As Example 3: FIG. 2 is a raw material processing flow of ferrite powder production as an embodiment of the present invention in an iron mill. Table 4 shows the material balance when iron ore B in Table 2 is used. Thus, it is possible to improve the quality of iron ore and produce ferrite powder at the same time.

[0030]

[Table 4]

[0031]

As described above, according to the present invention, it becomes possible to use goethite iron ore powder containing high phosphorus, which has been unsuitable as a raw material for sinter, up to now. Manufacturing is also possible, effective use of resources,
Furthermore, it can greatly contribute to the cost reduction of steel production.

[Brief description of drawings]

FIG. 1 shows the relationship between the heating pretreatment temperature and the acid concentration of the goethite iron ore containing iron and the phosphorus and alumina contents in the iron ore after the pickling treatment when the mass ratio of the ore and the acid aqueous solution is 1. It is a drawing.

FIG. 2 is a drawing showing an example of a raw material processing flow for producing a ferrite powder as an embodiment of the present invention.

[Explanation of symbols]

 1 Goethite iron ore powder for sinter 2 Sieve 3 Iron ore powder of 1 mm or less 4 Iron ore powder on sieve 5 Heating device 6 Pickling treatment equipment 7 High-grade powdered ore 8 Pickling waste liquid 9 Sintering plant 10 Ferrite powder manufacturing equipment 11 Ferrite powder 12 Neutralizing solution or HCl

Claims (3)

[Claims] 1. A goethite iron ore powder containing 2.4% or more of bound water among sinter raw materials for blast furnace of 500 ° C. or more,
A method for improving the quality of a goethite iron ore containing sinter, which comprises heating to 1,200 ° C. or lower and contacting it with an aqueous solution of sulfuric acid or hydrochloric acid having a normality (N) or higher to elute impurities. 2. The method for improving the quality of a goethite iron ore containing sinter according to claim 1, wherein the goethite iron ore containing powder is a fine powder portion of the goethite containing iron ore containing 1 mm or less. 3. A method for enhancing the quality of a goethite iron ore containing sinter according to claim 1 or 2, wherein an acid treatment waste solution of an aqueous solution of sulfuric acid or hydrochloric acid in which impurities are eluted is used as a raw material for producing ferrite powder. .