JPS61217548A - High purity phosphor iron and method for refining same - Google Patents

Abstract

PURPOSE:To obtain high purity phosphor iron contg. reduced amounts of Si, Al, C, Ca and Mn by subjecting phosphate ore, silica, a carbonaceous reducing agent and raw material bearing iron to reduction smelting in an electric furnace, adding a flux to the resulting molten phosphor iron and agitating them. CONSTITUTION:Phosphate ore, silica, a carbonaceous reducing agent and raw material bearing iron are subjected to reduction smelting in an electric furnace. A flux contg. >=10wt% P2O5 is added to the resulting molten phosphor iron and agitated to obtain high purity phosphor iron having a composition consisting of, by weight, 15-30% P, <1% Si, <1% Mn, <0.1% Al, <0.1% Ca, <0.1% C and the balance Fe with inevitable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to iron phosphorus and a method for refining the same, in which Si, kl, which is contained as an impurity in iron phosphorus produced by an electric furnace method, is , Q, Oa, In, etc., and a method for purifying the same.

(Prior art) A conventional method for producing iron phosphate involves reducing and smelting phosphate rock containing phosphorus oxide in an electric furnace using silicate flux and a carbonaceous reducing agent to form an Fe-P alloy. Electric furnace method; Synthesis method for obtaining high-purity iron phosphorus by heating and holding pure iron and red phosphorus under pressure; Electrolytic method for electrolyzing iron fluoride and sodium metaphosphate at 925° C., etc. are known.

Among these methods, iron phosphate produced by the electric furnace method has the highest productivity and is the cheapest, but it is produced by reduction smelting in an electric furnace using phosphate rock, scrap iron, silica stone, and coke as raw materials. Therefore, Si, kl contained in these raw materials
, Ca, C, Mn, etc. cannot be avoided, so the content of SilAj lcarC is more than 0.1 wt% in most cases, especially Si.

Even if kn is low, it is 1 wt% or more, and Si is generally 4
~5 wt%.

On the other hand, iron phosphorus produced by synthesis or electrolysis has high purity, but has low productivity, and products produced by these methods are very expensive.

Conventionally, phosphorous iron has been used as a master alloy for adding phosphorus to free-cutting steel, castings, powder metallurgy, etc., but for this type of use, Si is a slight problem, and other impurities are , there were no major problems.

(Problems to be Solved by the Invention) Amorphous alloys have been in the spotlight in recent years, but in order to manufacture these alloys, P and 0 are used as amorphous elements.
．． It is considered essential to add one or more metalloid elements such as B.

Among these metalloid elements, when phosphorus is added in elemental form, the addition yield is extremely low and the component accuracy is poor.
It is desirable to add it in the form of -P.

However, phosphorus iron produced by electric furnace method usually contains 1 w
Since it contains t% or more of Si, Mn, and 0.1 wt% or more of Ga and AltC, such iron phosphorus cannot be used when manufacturing alloys that dislike these impurities.

For the above reasons, it is desired to provide highly pure and inexpensive phosphorus iron when manufacturing amorphous alloys.

(Means for solving the problem) As mentioned above, phosphorous iron produced by the conventional electric furnace method has high productivity and can provide relatively cheap phosphorous iron, but Si + kl during smelting,
Due to the contamination of Ga + 0, Mn, etc., there were restrictions in terms of use.

As a result of extensive studies, the present inventors have found that impurities in phosphorous iron produced by the electric furnace method can be removed by flux treatment or by blowing oxidizing gas during flux treatment to produce high-purity phosphorous iron. We have newly discovered that it can be purified to

These methods will be described in more detail below.

The main component composition of iron phosphorus produced by the electric furnace method is generally P20 to 28 wt%, Si4 wt% or so, and large amounts of Si, Al, and 0.5% as impurities. Ca+M
n and the balance is Fe, and its melting point is 1150-1350
The specific gravity at 9°C is approximately 6.

The present inventors received molten phosphorus iron, which is normally tapped from an electric furnace at 1300 to 1450°C, into a ladle, and added 5 to 30 wt% of flux mainly composed of phosphate ore to the molten phosphorus iron. , Si, AJ, without reducing the P in the iron phosphorus by stirring or by blowing an oxidizing gas into the molten metal together with the stirring treatment.
It has been found that highly purified iron phosphorus with low contents of Ca, G, and In can be produced.

The treatment temperature at this time varies depending on the composition of the iron phosphorus to be treated and the flux added, but is generally higher than the melting point of the iron phosphorus and the flux, preferably 1350 to 16
00℃ is good.

If the treatment temperature is lower than 1,350°C, the reaction rate will be reduced and the reaction time will be longer, resulting in poor separation of iron phosphorus and slag after treatment. On the other hand, if the temperature is higher than 1,600°C, volatilization loss of phosphorus will occur. The processing temperature must be within the range of 1,350 to 1,600° C., since this increases the temperature, generates intense white smoke, impairs workability, and lowers the energy utilization rate.

The types of flux used in the present invention include P2O
A flux containing 510 to 50 wt% and having a basicity in the range expressed by the following formula is suitable, especially P.
A flux with 528 to 35 wt% of 2O and a basicity of 1°O to 1.4 is desirable.

Using such fluxes prevents phosphorus loss and
Moreover, impurities such as Si I It , Ca, C, and Mn can be reduced.

The reason why the P2O5 in the flux is set to 10 to 50 wt% is that when the P2O5 in the flux becomes 10 wt% or less, the phosphorus loss in the molten iron phosphorus increases.The reason why the upper limit is set to 50 wt% is that This is because even if P2O5 is increased more than this, no further effect can be obtained.

To explain the relationship between the composition of the flux and the above impurity elements, when it is desired to keep the Si content in the purified iron phosphorus low, the basicity is increased.Ca.

If it is desired to keep Mn low, it is better to lower the basicity, but generally 7 lux with a basicity of 1.0 to 1.6 is used.

Further, although phosphate rock is mainly used as the flux, a slack containing oxides and/or fluorides such as si, Ca + Kg t A1, etc. can also be used together with a raw material whose main component is phosphate rock or P2O5.

The amount of flux added depends largely on the content of impurities to be removed; if the content of impurities is small, iron phosphorus with the desired composition can be obtained with a small amount of flux, but iron phosphorus obtained by the electric furnace method When refining the flux, the appropriate amount of flux to be added is 10 to 30 wt%.

Usually, the Si content of iron phosphorus produced by the electric furnace method is about 4%, and the total amount of impurities is 5 to 6 wt%, so the amount of flux added needs to be about 30 wt% of the weight of iron phosphorus. When dividing the slack into 3 to 4 times and repeating the flux treatment and the sludge removal treatment 3 to 4 times, the desired purity can be achieved by using 7 lux of the same composition at about 15 wt% based on the weight of phosphorous iron. You can get iron phosphorus.

When flux treatment and oxidizing gas blowing treatment are used together, iron phosphorus of the desired purity can be obtained with an even smaller amount of flux.

According to the present invention, an oxidizing gas such as 02 + 002 or a mixed gas of an oxidizing gas and an inert gas such as N2 + Ar is applied to the bottom of the ladle containing the molten metal, with or without the use of flux. It is also advantageous to blow the liquid into the molten metal, or onto the surface of the molten metal in the ladle or into the molten metal. By doing this, the molten metal in the ladle can be stirred and smelted, which can be used as an alternative to shaking the ladle or stirring using a stirring blade.

In this way, by blowing or blowing the oxidizing gas into the molten metal, impurities in the molten metal can be rapidly oxidized to form slag.

Furthermore, by suspending powdered flux in the above gas and blowing it into the molten metal, the contact between the flux and the molten metal becomes extremely good, and the impurity removal reaction at the interface between the molten metal and the flux takes place quickly and completely. There are advantages.

Further, in order to improve the contact between the molten metal and the flux, electromagnetic stirring can be performed using an induction furnace.

Next, the present invention will be explained by examples.

Example 1゜Phosphate iron molten metal 3,54 obtained by electrical reduction smelting
To 0? *1ooo of phosphate rock poured into a carbon-lined ladle and preheated to 1.270°C as a flux
Q was added, a 3-phase carbon electrodeless electrode was inserted and electricity was applied, and 1
After raising the temperature to 550°C, transfer to a rocking stirrer and stir.
After shaking and stirring for a minute to remove slag, it was poured into a cast bed. Table 1 below shows the composition of the flux used, and Table 2 below shows the composition of iron phosphorus before and after flux treatment.

As can be seen from Table 2, by flux treatment, P increases and SL r Al * Ca
Both sG and kn were significantly reduced, and it was possible to obtain the initial high-purity iron phosphorus.

Example 2゜Phosphate iron molten metal similar to that used in Example 1 2.980
Pour Kp into a carbon-lined ladle and preheat it to 1,230'C as a flux. Add 300 Kp of 80 parts of phosphate rock and 20 parts of quicklime shown in Table 1 as a flux and heat to 550°C. The mixture was stirred for 10 minutes using a carbonaceous stirring blade. After that, remove the slag and repeat 1 or 2
Preheated to 50°C. 9 was added to the blended flux 300, heated to 1,550°C, stirred for 10 minutes using a carbonaceous stirring blade, and after removing sludge, the mixture was poured into a cast bed. Table 3 shows the phosphorous iron composition before and after flux treatment.

According to this example, by dividing the flux used to obtain the desired high-purity iron phosphorus into two treatments, it was possible to significantly reduce impurities and reduce the amount of flux used. .

Example 3゜Phosphate iron molten metal 2.850 similar to that used in Example 1
Ky was poured into a carbon-lined ladle and heated to 1.230.
A blended slack preheated to ℃ is a mixture of 50 parts of phosphate rock and 50 parts of quicklime shown in Table 1.Add 9 to 140 and add Ar gas/C150Ml/min from the bottom of the ladle *5 Nm' of oxygen gas from above the ladle. /min for 10 minutes, then remove the slag, add 140Kp of blended flux preheated to 1,230℃, and also add 140Kp of Ar gas from the bottom of the ladle.
50 Nl/min, 5 N oxygen gas from above the ladle
The product was blown at a rate of m'/min for 10 minutes, and after removing the slag, it was cast into a cast bed.

Table 4 shows the phosphorous iron composition before and after Franks treatment.

Table 4 Composition of iron phosphorus before and after treatment According to this example, the amount of flux used is at least good due to the use of oxygen gas, but on the other hand, the amount of phosphorus is slightly reduced.

However, the content of impurities could be sufficiently suppressed to the desired content.

Example 4 Phosphate iron molten metal 2,'yo, similar to that used in Example 1
OKy was poured into a ladle equipped with top and bottom blowing equipment, and while 150 Ml/min of Ar gas was introduced from the bottom of the ladle and the molten metal was stirred, oxygen gas was introduced at 10 Nm Ain from above the ladle.
The oxides floating on the phosphorus iron ball were completely removed by blowing for 10 minutes.

Next, 13 sKy of a mixture of 50 parts of phosphate rock and 50 parts of quicklime shown in Table 1 as a blended flux preheated to 1,230°C was added to the bottom of the ladle.1) Ar gas 150
Nj! /min, oxygen gas from above the ladle 5 Nms
/min for 10 minutes, and gas blowing and 7 lux treatment were used together. After treatment, the sludge was removed and cast into a cast bed.

Table 5 shows the phosphorous iron compositions before treatment, after gas blowing and slag removal, and when gas blowing and 7 lux treatment were used together.

Table 5 Composition of iron phosphorus before and after treatment As shown in Table 5, by blowing in an oxidizing gas, impurities are significantly reduced, but the oxidation of the active ingredient phosphorus also progresses slowly. However, by first oxidizing and removing $1, which has the highest content, by gas blowing, then adding flux, and treating it in combination with gas blowing, the loss of phosphorus in the metal can be completely suppressed, and impurities can be effectively removed. I was able to remove it.

(Effects of the Invention) According to the present invention, impurities such as sir ht + ct Oa e Kn, etc., which are avoided during the production of amorphous alloys, can be reduced without significantly changing the phosphorus content in molten phosphorus iron. In addition, the purification method according to the present invention has the industrial advantage of high productivity.

Claims (1)

[Claims] 1. P15-30wt%, Si1wt% or less, Mn1w
t% or less, Al 0.1wt% or less, Ca 0.1wt% or less, C 0.1wt% or less, and the balance is substantially Fe. Phosphorous iron. 2. By adding flux to the molten iron phosphorus obtained by reducing and smelting phosphate rock, silica stone, carbonaceous reducing agent, and iron-containing raw material in an electric furnace and stirring it, Si contained in the molten metal can be removed. , a method for refining high-purity iron phosphorus, characterized by reducing the contents of Al, C, Ca, and Mn. 3. The flux is made of phosphate rock having a P_2O_5 content of at least 10 wt%.
The method described in section. 4. The method according to any one of claims 2 to 3, wherein the flux mainly consists of phosphate rock and also consists of oxides and/or fluorides of Ca, Mg, Al, Si. 5. The method according to any one of claims 2 to 4, wherein the amount of the flux added to the weight of the phosphorous iron molten metal is 5 to 30 wt%. 6. Flux is added to the phosphorous iron molten metal obtained by reduction smelting of phosphate rock, silica stone, carbonaceous reducing agent, and iron-containing raw material in an electric furnace, and oxidizing gas or oxidizing gas and inert gas are added to the molten metal. By blowing a mixed gas with gas or stirring while blowing, the Si contained in the molten metal is removed.
, a method for refining high-purity iron phosphorous, the method comprising reducing the contents of Al, C, Ca, and Mn. 7. The method according to claim 6, wherein the flux comprises phosphate rock having a P_2O_5 content of at least 20 wt%. 8. The method according to any one of claims 6 to 7, wherein the flux mainly consists of phosphate rock and also consists of oxides and/or fluorides of Ca, Mg, Al, and Si. 9. The method according to any one of claims 6 to 8, wherein the amount of the flux added to the weight of the phosphorus iron molten metal is 5 to 30 wt%. 10. According to any one of claims 6 to 9, the oxidizing gas is a mixed gas of at least one of O_2 and CO_2 or at least one of O_2 and CO_2 and an inert gas. Method described. 11. Part or all of the added flux is suspended in powder form in the oxidizing gas or a mixed gas of an oxidizing gas and an inert gas, and is added to the molten metal.
10. The method according to any one of Item 10. 12. Injecting an oxidizing gas or a mixed gas of an oxidizing gas and an inert gas into the molten iron phosphate obtained by reducing and smelting phosphate rock, silica stone, a carbonaceous reducing agent, and a ferrous raw material in an electric furnace, or A method for refining high-purity iron phosphorus, comprising reducing the content of Si, Al, C, Ca, and Mn contained in the molten metal by spraying and stirring the molten metal. 13. Injecting an oxidizing gas or a mixed gas of an oxidizing gas and an inert gas into the molten iron phosphate obtained by reducing and smelting phosphate rock, silica stone, a carbonaceous reducing agent, and a ferrous raw material in an electric furnace, or After spraying and stirring the molten metal, removing slag on the surface of the molten metal, adding flux and stirring to reduce the Si, Al, C, Ca, and Mn contents contained in the molten metal. A method for refining high-purity iron phosphorus. 14. The method according to claim 15, wherein the flux comprises phosphate rock having a P_2O_5 content of at least 10 wt%. 15. The method according to any one of claims 13 to 14, wherein the flux mainly consists of phosphate rock and also consists of oxides and/or fluorides of Ca, Mg, Al, and Si.