JPS6134122A - Method for separating and recovering element convertible into basic oxide incorporated in molten iron - Google Patents

Abstract

PURPOSE:To separate and recover efficiently and selectively valuable elements convertible into basic oxides incorporated in a molten iron when the molten iron is refined by oxidation, by adding the specified amount of a flux contg. B2O3, which is an acidic oxide as the principal component, oxidizing the elements convertible into basic oxides at a specified temp., and transferring selectively the resulting oxides to the slag. CONSTITUTION:When the molten iron is refined by oxidation, a flux contg. B2O3, which is an acidic oxide as the principal component is added in <0.3 ratio of MOx/B2O3 (M is an element convertible into basic oxide in the molten iron). The elements converticle into basic oxides such as Mn and Ni are then oxidized at 1,400-1,500 deg.C, and the resulting oxides are selectively transferred to the slag.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for selectively separating and recovering elements that form basic oxides, which are valuable elements contained in hot metal, such as Mn and Ni.

Prior Art As a conventional treatment method for separating element B contained in hot metal, a method is used in which a basic oxide flux is used to remove phosphorus and sulfur, which are harmful to steel materials. As a method for recovering other elements, soda ash (NazOOi), which is a strong basic oxide, is used to recover phosphorus contained in hot metal,
A method has been developed to remove sulfur and simultaneously recover vanadium during the soda ash recovery process. If this method is too busy, valuable elements that become basic oxides cannot be recovered. Furthermore, the elements remaining in the hot metal that become basic oxides become contaminants when other valuable elements are separated and recovered, so it is desirable to separate them in advance.

However, a treatment method for actively separating and recovering low-concentration valuable elements contained in hot metal, particularly a method for selectively separating and recovering valuable elements that become basic oxides, is not yet known.

OBJECTS OF THE INVENTION An object of the present invention is to provide a method for treating hot metal that selectively separates and recovers elements that form basic oxides contained in the hot metal, such as Mn and Ni.

Structure of the Invention The present inventors have achieved the above object.As a result of intensive research, it was found that silicon contained in hot metal was desiliconized by blowing oxygen gas or adding iron oxide [7, and this desiliconizing slag was removed. After that, a flux mainly composed of boron oxide was added to the hot metal at 1400 to 1500°C at a concentration of MOx/B2O5 (0.3 (however, M
represents an element that becomes a basic oxide) and oxidizes by blowing in oxygen gas or adding iron oxide,
Elements that become basic oxides are oxidized and transferred to slag. It has been found that elements that form basic oxides can be easily and selectively separated and recovered from Kyoyo slag. The present invention was completed based on this knowledge.

The gist of the present invention is that during the oxidative refining of hot metal, a flux mainly composed of boron oxide, an acidic oxide, is used as MOx /B
Add the amount of zOs < 0.3 (however, M represents an element that becomes a basic oxide), 1.400 to 1500°C
A method for separating and recovering elements that become basic oxides contained in hot metal, characterized by oxidizing the elements that become basic oxides and selectively separating them into slag.

It is preferable that most of the Si contained in the hot metal in the present invention be removed in advance as described above. S in hot metal
This is because if i remains at a high concentration, the concentration of the element to be recovered in the slag in the subsequent process will decrease. but,
If an attempt is made to remove Si by excessive oxidation, the element to be recovered will also be oxidized at the same time, reducing the recovery rate of the element.
It is desirable that the oxidation removal rate of Si is such that the oxidation removal rate of the recovered element is 10 or less.

The flux B2O3 used in the present invention has a low melting point (
450° C.) and becomes liquid at the hot metal treatment temperature, it has good reactivity and is easy to separate the slag from the hot metal after treatment. However, since it is an acidic oxide, it combines with the basic oxide in the slag and retains the basic oxide in the slag. As a result, elements that become basic oxides in the hot metal are transferred to the slag. During this process,
improve the contact between hot metal and slag to promote the reaction,
Adequate agitation is preferred to increase selectivity.

If the treatment temperature is lower than 1400°C, all the elements contained in the hot metal will be oxidized and removed, making it difficult to select the elements to be removed. If the temperature is higher than 1500'C, the recovery rate of the valuable elements to be recovered will decrease, so the temperature is preferably 1400 to 1500C.

The amount of B2O2 added must be MOx /B2O3 (0.3) in order to make the selective recovery of elements effective. If BzOslj is a little more than this, elements coexisting in the hot metal other than the target elements to be recovered may be added. In order to improve the recovery rate of recovered elements, there is a limit to the proportion of coexisting elements mixed in.

To prevent this, it is preferable to adjust the oxidation strength as well.

A slag consisting of a flux mainly consisting of B2O3 containing the target elements to be separated and recovered is separated from the hot metal 7, and is poured into high-temperature water. Since B2O3 easily dissolves in high-temperature water, the oxide of the element to be recovered and B2O3 can be easily separated by filtration. By cooling the obtained high temperature water, BzOs can be crystallized. Since this B2O3 can be recycled and used, it does not cause any pollution.

Effects of the Invention According to the method of the present invention, the following excellent effects can be achieved.

l) By using a specific proportion of B201 as a flux, valuable elements contained in hot metal that become basic oxides can be selectively separated and recovered] 7. It can be utilized as a new resource.

2) Since elements that become basic oxides from hot metal are contained in B20m slag, it is easy to recover the elements due to the water-solubility properties of 1h (h).

3) Valuable elements contained in pig iron manufactured from iron ore containing various elements are successively separated and used as new resources, and at the same time, by removing these elements, it can be used for the manufacture of high-quality steel materials. can get. Therefore, unused iron ore can be utilized as a new resource.

Example Hot metal obtained from iron ore containing niobium, ma/ga/, and phosphorus was subjected to a desiliconization treatment to reduce the silicon concentration to 0.13 h. The obtained desiliconized hot metal (carbon concentration of hot metal - saturation) K was treated at 1400° C. by adding B2O2 at a rate of 20 to 9 per ton and iron oxide at a rate of 25 Kf per ton of hot metal. Before processing,
The composition after treatment was as follows.

Elements contained in hot metal Mn Nb Si I
Composition before treatment (wt) O, fi2 ('16
2 0.13 0.46 Composition after treatment (wt) 0
．． 18 0.57 0.015 0.46 Removal rate (%)
? 1.08.1 88.5 0 As these results show, 71.0% of Mn, which becomes a monobasic oxide, is removed, while only 8.1% of Nb, which becomes an acidic oxide, is removed. Not too much. P is not removed at all and is easily VcIIP
Although 885 pieces of Si were removed, the concentration was low because the slag had been kept at a low concentration in advance.

Next, the slag was dissolved in 100°C water. (At 20° and 100°C, 5f x 15f per 100f of water, respectively)
dissolve. ) The composition of the slag before and after water treatment was as follows.

Slag component B*Ox MnONbzOs 5iOi
Composition before FeO treatment (wt) 629 17.9 2
3 Composition after 12050 treatment (wt) 48
．． 1 6.1 320 135 As shown in this result, by water treatment of slag, the M n O concentration was 48.1
%, which is higher than the minimum concentration of 31% as a raw material for producing metallic manganese, and dissolved in the water obtained when fFjl is used as a raw material for producing metallic manganese. Can be reused and obtained.

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Claims (1)

[Claims] During oxidative refining of hot metal, a flux mainly composed of boron oxide, an acidic oxide, is used at MOx/B_2O_3<0.3 (
However, M represents an element that becomes a basic oxide), and the element that becomes a basic oxide is oxidized at 1400 to 1500°C and selectively separated into slag. A method for separating and recovering elements that become basic oxides.