JPS603011B2 - Production method of high-grade iron oxide for ferrite magnetic materials - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high-grade iron oxide for use in ferrite magnetic materials from crude iron oxide produced in the residue treatment process of grain-type zinc smelting.

In wet zinc smelting, zinc sulfide ore is enriched to obtain Akatsuki ore, which is mainly composed of zinc oxide, and when this is leached with zinc electrolytic tailings, a considerable amount of zinc is released into the ore during the barrel bran process. It combines with accompanying iron to form eluent-soluble zinc ferrite, which remains in the zinc leaching residue (zinc isosumi).

Various dry and wet methods have been proposed and implemented in order to recover the zinc in this zinc residual groove, but in the case of wet processing, iron is also forced out at the same time as zinc, and then the iron is precipitated and separated. A method is being taken to do so.

One of these hot processing methods is a method commonly known as the hematite method, in which iron is precipitated in the form of hematite.
The zinc residue is leached out in a reducing atmosphere, and a solution containing zinc and iron is obtained through treatments such as deodorization and neutralization, and this is heated at a temperature of 180 to 2
Pressurized oxidation at 00℃ oxygen partial pressure (P average) 1 to 5k9/m,
Iron is precipitated and separated as hematite-like iron oxide, and zinc is recovered by returning it to the leaching process of this system.

The iron oxide precipitated at this time usually contains impurities as shown in Table 1, and cannot be used as it is for ferrite magnetic materials. Table 1 Grade of iron oxide by hematite method The purpose of the present invention is to recover iron in this zinc residue as iron oxide for ferrite magnetic materials, and special conditions for removing impurities are added to the normal hematite method. Add the process of
The present invention provides a method for purifying the obtained iron oxide to obtain high-grade iron oxide.

That is, in the present invention, an iron-containing solution obtained by acid leaching the zinc leaching residue in wet zinc smelting is neutralized to pH 4 to 5 with a neutralizing agent such as calcium carbonate to reduce Si, Mt., and G in the solution.
A first step in which impurities such as a and ln are precipitated and separated together with gypsum, and zinc powder, etc. is added to the liquid from the first step in which the precipitate has been separated in the presence of hydrogen sulfide or steel to convert phosphorus into sulfide or chlorine. The second step involves precipitating and removing the precipitate in the form of chemically processed steel, and the second step liquid from which the precipitate has been removed is heated at a total pressure of 16 to 20 kg/G and at a temperature of 180
A third step in which iron is oxidized and precipitated by oxidation treatment under pressure and high temperature of ~200 qo, and the iron oxide precipitate obtained in the third step is
Zn in iron oxide is removed by pressure washing with 70-200qo hot water.
, Na, K and other impurities are eluted, and the iron oxide obtained in the fourth step is desulfurized at 700 to 1000°C,
The present invention provides a method for producing high-grade iron oxide for ferrite magnetic materials, which comprises a fifth step of pulverizing the obtained dawnite. The details of the method of the present invention will be specifically explained below according to Examples.

Figure 1 shows an outline of the flow sheet of the hematite process using the secondary method and the trend of impurities.As can be seen from Figure 1, in the conventional hematite process, various types of Impurities are dissolved, and during iron removal, they precipitate or coexist with iron and enter iron oxide.

Therefore, regarding the method of removing impurities before iron removal,
As a result of various studies and examinations, the final pH of the pre-neutralization process was determined.
By setting the temperature to about 4.9 degrees, Ga, ln "N, Si
It was found that each impurity can be effectively removed.

The results are shown in Table 2. In this test, the removal rate of each element in cast iron was investigated by changing the neutralization pH in the second stage using the solution after the first stage neutralization as the stock solution. Table 2 Neutralization conditions and trends of impurities (residual concentration in liquid) As can be seen from the results in Table 2, by setting the pH to approximately 4.5, the Zn residual rate is 95~
At 99%, AI: 6.7-8.9%, Si02-≠37
%, Ga=30-16%, ln=1.3-0.5%, and N, SiQ, Ga, ln, and Zn
It can be seen that they can be separated.

That is, when the feed content of the neutralized solution is increased, the residual rate of all substances other than Si02 decreases. In other words, the removal rate is improved. Zn is
Since it is necessary to keep the residual rate as high as possible (keep the loss low), the neutralization pH is preferably about 4.9 degrees in relation to the removal rate of Si02. Furthermore, the influence of liquid overflow in the neutralization process was tested at 60 to 8 pi○, but almost no difference was observed in the removal rate, etc. Next, with regard to the descaling treatment, it can be sufficiently removed by the method described in ``Method for descaling from an aqueous solution'' in 1982-141395 (Japanese Unexamined Patent Application Publication No. 74272/1993) filed by the same applicant or by hydrogen sulfide treatment. can. The results are shown in Table 3. Table 3 As removal test results ex. The method described in No. 1:74-74272 (Zn powder 2.0 g/Z, CuS04/today 200.5 g/was added, 60°C) ex. As a result of the above, As was removed by the method described in Tsubaki Seki No. 54-74272 and by the 2S blowing method. Although it was found that this method is possible, since Cd also precipitates in the case of the 2S method, the former method is preferable.

Table 4 shows the grade of iron oxide obtained from the liquid thus obtained by oxidation treatment at 200° C. and P = 3 [9/ground], which are the iron removal conditions of the usual hematite method.

Table 4 Iron oxide grade obtained from the neutralized As-degraded solution Fe-degrading conditions 200°C Po2co3k9/Sakai T/PF18
Omitted / Ground ○ Others Si02 0.02% AI20,8 0.05% Ca0 0.05% As o. 01% As can be seen from Table 4, in order to use this iron oxide for ferrite magnetic materials, impurities such as Zn, Na, K, and S must be further removed.

Therefore, purification tests were conducted under various conditions to remove these impurities. The results are shown in Table 5. Table 5 Iron oxide refining test results Pulp concentration 1009/poly Reaction time 3mPo2=3
As can be seen from Table 5 of kg/, Zn in the crude iron oxide can be removed extremely well by pressurized leaching with hydrochloric acid.

It was found that the pressure leaching method using overflowing water is effective for Na and K. The purification conditions are as follows:
Pressure washing using overflowing water of 180 to 20 psi is good. The impurity in the iron oxide thus obtained is substantially only S. This S can be effectively removed by volatilization with phosphorus during oxidation. The results are shown in Table 6. The higher the milling temperature is, the better the S removal rate is, but the hardness of the ore increases and the burden on the pulverization process increases, so it is set at 850 to 90. Table 6
As seen in the results of '1' and ■ in Table 6 of the S removal test results, there is a close relationship between the Ca, Na, and K grades and the S removal rate, and when the above components are high, the S removal temperature is 100. It must be increased to over 0.

The upper limit of flame temperature for industrial pulverization is 900.
Table 6 {2
} is a table. In order to further clarify the relationship between the S grade and the Ca, Na, and K grades after the S removal competition, this is shown in Figure 2. In the melting process below 90,000, Ca, Na, and K are converted to S in the form of CaS04, Na2S04, and K2S04, respectively.
It is thought that these components are fixed, so if these components are sufficiently removed in the pretreatment step, the S grade after S-removal flaming can be kept low.

The calculated values marked with ○ in Figure 2 indicate that the S grade after flaming is Ca, Na.
, the results calculated assuming only S fixed to K are shown. A system diagram of the method for producing high-grade iron oxide for ferrite magnetic materials according to the present invention, which involves the above-mentioned steps, is summarized in FIG. 3.

Incidentally, FIG. 3 also shows the quality of the high-grade iron oxide obtained. Next, using the obtained high-grade iron oxide as a raw material, an isotropic barium ferrite magnet was actually prototyped and its magnetic properties were measured.

The magnetic sample was prepared using a known method, and the sample was coated with Ba○.5.
Mix BaC03 so that it becomes 1Fe203, and then add Si
Q.O. Add 55% and mix well for 18 minutes in a dry ball mill, add 0.5% polyvinyl alcohol solution to make green balls with a diameter of 1 mm, dry at 60 qo for 10 hours, and mix in a false oven at 1050 ° C. Barium monoferrite is made by annealing at high temperature for 2 hours, and then made into a dry board.
Finely pulverize to one size with Lumil and fill it into a mold to make Iton.
A piece of 10 ribs in diameter and 1 square in height was pressure-molded in a baking furnace at 120 mm or 123 mm for 1 hour. The results of magnetic measurement of the thus obtained isotropic barium ferrite magnet are shown in Table 7, and it is confirmed that the iron oxide purified by the method of the present invention and the commercially available high-grade iron oxide are equivalent. I was caught. Table 7 Magnetic measurement results In Table 7, R is the radial direction, L is the longitudinal direction, and B
is the residual magnetic flux density (Gauss), 8Hc is the coercive force (Oersted), , Hc is the true coercive force (Oersted), (B
H) max indicates the maximum energy product.

Although the above magnet is a barium ferrite magnet,
The iron oxide according to the present invention can also be applied to other ferrite magnets.

[Brief explanation of drawings]

Figure 1 is a flow sheet diagram of the hematite method, Figure 2 is a relationship between the Na, K, and Ca levels in iron oxide before enlightenment and the S level after melting, and Figure 3 is according to the method of the present invention. It is a flow sheet diagram. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. The iron-containing solution obtained by acid leaching the zinc leaching residue in wet zinc smelting is adjusted to pH 4-4 with a neutralizing agent such as calcium carbonate.
A first step in which impurities such as Si, Al, Ga, and In in the solution are precipitated and separated together with gypsum by neutralization treatment up to 5, and the first step solution in which the precipitate has been separated is treated in the presence of hydrogen sulfide or copper. The second step is adding zinc to precipitate and remove arsenic in the form of sulfide or copper arsenide, and the second step solution from which the precipitate has been removed is heated at a total pressure of 16 to 20 kg/cm^2G and a temperature of 180 to 200°C.
The third step is to oxidize and precipitate iron by oxidation treatment under pressure and high temperature, and the iron oxide precipitate obtained in the third step is
The fourth step is pressure washing with hot water at ℃ to elute impurities such as Zn, Na, and K in the iron oxide, and the iron oxide obtained in the fourth step is desulfurized and roasted at 700 to 1000 ℃. A method for producing high-grade iron oxide for ferrite magnetic materials, comprising a fifth step of pulverizing the burned ore.