JPS58110009A - Manufacture of metallic magnetic powder comprising iron as main component - Google Patents

Abstract

PURPOSE:To remarkably reduce the cost of manufacture by a method wherein neutralizing oxidation is performed by adding a V compound into a ferrous salt solution to prepare alpha-FeOOH containing V. CONSTITUTION:Neutralizing oxidation is performed by adding a V compound into a ferrous salt solution, and alpha-FeOOH containing V is prepared. After performing treatment additionally adhering an oxide or a hydrate of one or more kinds of Ni, Co, Zn, Mn, Cr, Ca and Si, and a V compound, if necessary, to the alpha-FeOOH, dehydrating reduction is done under H2 gas current. In this way, metallic powder having physical and chemical stability and high magnetic characteristics and comprising iron as a main component is obtained. This manufacturing method can prepare alpha-FeOOH having good acicular and uniform particle size from a relatively impure ferrous salt solution. Furthermore, since reduction can be executed with a very small amount of H2, the cost of manufacture can be remarkably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for economically producing a metal magnetic powder whose main component is a metal magnetic powder that is not suitable for high-density recording.

Currently, needle-shaped magnetic iron oxide powder and cobalt-modified magnetic iron oxide powder are widely used as magnetic powder for magnetic recording1, but in recent years there has been a demand for higher density magnetic recording. , metal magnetic powders whose main component is acicular iron suddenly began to attract attention. Metal magnetic powder whose main component is iron has high magnetic properties such as coercive force (Hl) and magnetic flux density (σ), making it suitable as a magnetic powder for density recording, but it is difficult to manufacture using current manufacturing methods. The cost is extremely high and is a major obstacle to expanding its use.

That is, in the conventional method, the starting material α-yeon must be prepared from a sufficiently purified ferrous salt solution, and Ni, Oo, Kn.

Mn, ar, Mut, Oa, MO, W, Ei, Mug, 8b, Ti, an.

Among many other component compounds such as Ou, At, and Si, 1. α-? 5OO)l is subjected to pre-treatments such as adhesion, dehydration and hardening, and then a large amount of H2 is supplied to reduce it to metal.

Compared to conventional methods, the present invention is capable of producing α-1pe suitable for producing metal magnetic powder mainly composed of iron from a much more impure ferrous salt solution.
oon was prepared, and a significantly smaller amount of H2 was added compared to the conventional method.
The present invention provides a method in which the reduction can be completed by the following steps, and the manufacturing cost can be significantly reduced. That is, in the present invention, when preparing α-7600H, a vanadium compound is added to a ferrous salt solution to perform neutralization oxidation, and V-containing a-Fe0OHt-vI4
@ L, the a -? eOOH contains Ni, Co, Zn,
It is characterized by dehydration and reduction with a compound of one or more oxides or hydrates of Mn, Or, Ca, 81 and, if necessary, V. In order to further enhance the effectiveness of the present invention, α -FeOOH with Ni and Co.

When attaching one or two oxides or hydrates of Zn, Mn, Or, Oa, and Si and, if necessary, a vanadium compound, υ, Pl (vI4, ammonia is used as a precipitant, and In the dehydration and reduction of α-?eOOH, the temperature is set at 300 to 550°C, and the H2 violet supplied during dehydration and reduction to magnetite is kept below 60 Ht per hour per 1 kg of Pa. The amount is set at 900M1 or more per hour per Pe1Kf.

In general, metal magnetic powder whose main component is iron has high coercive force and magnetic density, and in order to be used as magnetic powder for high-density recording, it must have an acicular shape, an appropriate particle size, and uniformity. Although it is necessary that no agglomeration of particles occurs due to sintering, etc., in order to produce such metal magnetic powder mainly composed of iron by the conventional method, a sufficiently purified ferrous salt solution must be used. It is necessary to use backed α-FeOO)I, and even if surface treatment is performed on the α-IPeOOHK% seed component to improve the stability of the reduction product, a large amount of It requires H2. The reason why the conventional method requires a highly pure ferrous salt solution is because of its purity.From the ferrous salt solution, it is easy to grow α-FeOOH particles uniformly, and it is also easy to obtain crystals with excellent needle shape. Karademe group,
The reason why a large amount of E2 is required during reduction is that Pa30. + H2: Fe + H20 small amount of H2
The supply amount is Hgo (J/), which is one of the reduction products.
Large and small partial pressures tend to occur in the reactor, so microscopically there are areas where the rightward reaction is progressing, areas where the reaction is in equilibrium, and even areas where the leftward reverse reaction is occurring. It is thought that this occurs and causes the particles to collapse. In other words, supplying a large amount of H2 is one means of making the rightward reaction proceed as smoothly as possible at an appropriate speed and preventing the collapse of the acicular particles as much as possible.

On the other hand, it goes without saying that the amount of H2 supplied during reduction has a great influence on the manufacturing cost of metal magnetic powder whose main component is iron.

In the conventional method, one of the many component compounds as described above
The species or two or more species are α-FeOOH, a-Fe20. .

It has been proposed to add it to γ-'Ife@0B for reduction, but this prevents particle collapse and agglomeration due to sintering during reduction, increasing the physical and chemical stability of the metal magnetic powder. It is not only effective in reducing the amount of H2 supplied during reduction, but also has great potential in reducing the amount of H2 supplied during reduction. That is, the appropriate component is α-7600H, CI-Fe2
O3 or r-Fe2O, it is possible to produce metal magnetic powder with high magnetic properties in a relatively small amount of hm and supply amount. By adding a vanadium component to a ferrous salt solution that is
1 p! 111 at the time of reduction,
00. By coexisting V in addition to one or more components selected from Zn, Mn, Or, ca, and Eli, the present invention can be made physically and chemically stable and highly magnetic. The following is 9. Conventionally used α-7elon is extracted from an acid solution of iron.
Crystals of F e 804, 7H20, etc. are crystallized and redissolved in water, or high purity iron such as electrolytic iron powder is dissolved in sulfuric acid, hydrochloric acid, etc. 1.Made by neutralizing and oxidizing iron salt solution.

When using a ferrous salt solution such as a pickling waste solution of 0 irons or a general acid solution as a raw material for producing α-FeOOH, the ferrous salt solution contains a large amount of Mn. , and others (u, Zn, Sin, etc.), as described above, the appropriate grain size growth of α-FeOOH is hindered, and the grains tend to become irregular and fine.

As mentioned above, the present inventor Shun has obtained α-1θOOHt having good acicularity and uniform particle size from relatively impure ferrous salt S liquid.
- As a result of experimenting to determine whether α-7elon has a crystal growth effect on a large number of metal components that have an affinity for metallic iron, we found that
It was discovered that it has a crystal growth effect of FeOOH. The V added to the ferrous salt is effective regardless of whether it is a water-soluble salt such as vanadate or vanadyl salt;
The appropriate amount of V added to the iron salt is in the range of 0.05 to 1.096 in terms of atomic weight ratio to We. If the particle size is more than 1, the particle size becomes too large and is not suitable. Figure 1 shows excess NaOH using the waste liquid from hydrochloric acid pickling of iron plates as raw material, as described in Comparative Example 1.
The Fe(OH)2 produced is approximately 1.
9α obtained by air oxidation at a rate of 5 to 2 b/m3・H
Figure 2 is an electron micrograph of -PeOOH. As described in Example 1, 0.296 atomic weight ratio of V to We was added to the hydrochloric acid pickling waste solution, and Figure 2 is the same as in the case of l@1 diagram. Neutralize and oxidize with the operation of! α-1・
It is an electron micrograph of 0OIi. From the figure, the crystal growth effect of V is clearly recognized.

The present inventors conducted various experiments to examine the effects of V added as a crystal growth agent for α-FeOOH during thermal reduction by HlK, and found that V is included even in the thermal reduction process by B2. It has been found that when reducing α-FeOOH, which is not present, the reduction can be carried out with a much smaller amount of B2, and a metal magnetic powder having excellent magnetic properties can be obtained.

Although a wide variety of components have been proposed to be added to iron oxide particles before reduction, there has been no mention of the effect of adding V.・0The effect of V is still unclear. Although it has not been set as
This is thought to be because it is easy to form a stable alloy with E and has a contact effect that activates H2. ■This kind of effect is caused by Ni.

It can be synergistically enhanced by using one or more of Co, Zn, Mn, Or, Oa, 81, etc. together with V. That is, α-F@0 containing V
OIli contains Ni, Co, Zn, Mn, Or,
After performing a process of adhering one or more oxides or hydrates of Oa, Si, etc. and, if necessary, a V compound, thermal reduction is performed in H1. The amount of these additive components in terms of atomic weight ratio to Fe is effective within the following range, and if it is outside this range, it may be uneconomical or may even result in a decrease in magnetic properties. That is, Vo,
05-82.0%, Co 1-30%, N10.5
~10%, Or 0.05~1.0%, Mn
Q, b~5.0%.

KnO, 5-5.01 Ca 0.05-1.0%
1810.2~6ts. These components used in the present invention may be any water-soluble components, but nitrates or organic salts and silica sol, which do not require washing with water after addition, are preferred.

The conditions for attaching other components to α-1θOOH in the present invention may be substantially the same as in the conventional method, but the following method is more effective. That is, α-76001 containing (1) is well dispersed in water, and Ni, Co, Zn, and Mn are added.

Add 1 m or 2 m or more of the above-mentioned water-soluble salt or sol of Or, Oa, 81 and the water-soluble V compound as necessary, and while stirring, gradually add ammonia, and adjust the pH to 8.
After adjusting wI4 to ~10, dehydrate and dry. When these soluble salts are nitrates, organic salts, and silica sol, washing with water after dehydration is not necessary. Also, kneader α-F
The method of kneading elon, additive components, and ammonia and drying it is equivalent to the slurry stirring method.
Or even better effects can be expected. The temperature for the above-mentioned adhesion treatment is effectively 50 to 80° C. in the case of the slurry stirring method, and sufficiently effective at room temperature in the case of the kneading method. Ammonia is the most preferable regulator used in the process of adhering other components to α-'Fe0OIl, which eliminates the need for washing with water after the adhesion process and provides the best adhesion effect.

By the method of the present invention, V and Ni, Oo, Zn,
Mn.

When dehydrating and reducing α-FeOO)I to which one or more of Or, Oa, and 81 components are attached, it is a metal magnetic material that has sufficiently satisfactory magnetic properties even when carried out under the same conditions as the conventional method. Although a powder can be obtained, it is possible to reduce the 9α-Felon from the start of dehydration to near magnetite at 300 to 550°C without performing dehydration and annealing in an air stream as in the conventional method. The supply amount of B2 is 60 in 91 hours per Fe1KF)i
t or less, and the reduction after magnetite is 600 to 550
C. Fe1Kp and B2 supply amount of 900 N2 or more for 91 hours. As in the present invention, reduction from dehydration to magnetite is performed using a small amount of B2 supplied, and reduction from magnetite to metal is performed using a large amount of HI! If the reduction is carried out under the supplied amount, the magnetic property values such as He, σ, squareness ratio, etc. can be further increased with a small consumption amount compared to the general reduction method. The reason why the reduction to the vicinity of magnetite is performed with a small amount of Hs supplied is to allow the change in the large particle structure from dehydration to magnetite to proceed slowly. This is intended to be controlled by increasing the partial pressure. In other words, the reduction from dehydration to magnetite is 600 to 550
℃ and the supply amount of H8 is increased to FeIKf for 1 hour K 60
This is intended to deal with structural changes in large particles due to reduction from dehydration to near magnetite by reducing the temperature to ML or less, and it is expected to have an effect equal to or greater than that of baking before reduction of membrane flow, and the process This has the advantage that it can also be simplified.

In the present invention, B is used for the subsequent reduction after magnetite.
It is safe to keep the supply amount of 2 to 90ONt or more per hour per 1Kg of Pe, whereas -1500ONt is supplied by membrane flow.
Requires N1 or higher. Figure 6 will be explained later in Examples and Comparative Examples.
! : For the comparative example a-lFe0OH that does not contain Vfl, the atomic weight ratio TeNi to Fe before reduction, respectively.
49, Zn I To, Oa 015%, 81
1.51t-α-lFe0OH was added, dehydrated, and reduced with magnetite toma at 350-450°C.
The graph plots Ha on the vertical axis when treated with QN4/]FeKp・H for 5 hours and the subsequent reduction at 450°C for 10 hours while varying the amount of B2 supplied. The example shows that the reduction can be completed with much smaller amounts of B2 feed. Further, FIG. 4 shows the same examples of the present invention and comparative examples as shown in FIG. 3, in which dehydration and reduction to magnetite were performed at 650 to 450°C with a B2 supply amount of 50 HA71el14-11 for 5 hours, followed by subsequent treatment in the latter stage. Reduction was carried out at 450°C and the amount of R3 supplied was 1500 M.
A/PeKf-H toshiriage platform o rear stage.

This figure shows the relationship between reduction time and HC, and shows that the examples of the present invention are much easier to reduce.

Next, the present invention will be explained with reference to Examples and Comparative Examples〇Example 1 The waste solution from hydrochloric acid pickling of iron plates was diluted with water to give Fe" 2 Qνt, and this solution contained 500% sodium metaphosphate.
ppm, j fl:, NaVO3 to V and Lte 20p
pm (0.2% relative to IF), add 100 t of mixed solution to 130 ml of neutralized oxidation solution, and add NaOH3Q Q l! while stirring. / Add the solution,
The excess MaOH was adjusted to 3011/l. about 6
After cutting off the air for 0 minutes and continuing stirring, the liquid temperature was reduced to 45℃.
and air was supplied so that 1e+ was oxidized at a rate of 1.5 to 2.09/l-m. Completely 10 after 15 hours
was oxidized, so it was dehydrated and washed to obtain a filter cake with a water content of about 7°. Take this wet cake 1011 to 25 tons = Eider, N1 (No 3) 21 Zn (NO 3) 1 +
1 Ca(NOs)a+ and 5102 sol respectively
114% 5Zni% in atomic weight ratio to e, 0 & 0.5
Add NH, 31 in solution form so that it becomes 1, 5, 5, and 5 minutes.
0011/l of aqueous ammonia was gradually added to make -95. After about 15 minutes of second easing, heat to 100°C.
The dried product 12009 ('Ice: 5801) was placed in a capacity CD rotary heating reduction furnace, and the temperature was gradually raised and maintained at 650° C. for 2.0 hours. The temperature is determined by detecting the gas phase center of the rotary heating furnace, and from 200℃, N2 is 291Ai (0,4
8t/Min) "t' supply was started. After treatment at 350°C for 2 hours, the temperature was raised to 450°C with the 11 N2 supply amount and kept at this temperature for 5 hours. In this state, the reduced IFe The amount was 34.1% based on the total Fe.Subsequently, the temperature was maintained at 450°C, and the amount of N2 supplied was 8701%.
AX (equivalent to 15001/IPaKg-H) and treated for 10 hours.

After cooling, toluene was placed in a rotary heating furnace and the reduction product was taken out together with toluene and air-dried.
The manufactured round metal magnetic powder is peB3L, and other components are 4.06% Ni, 1.05% Zn, MnO, 1596,
0IL0.46%, 811.5896 was added and contained the amount of nine components. However, Mn was contained as 6 impurities in the hydrochloric acid pickling waste solution. In addition, the magnetic properties of this metal magnetic powder are 11c in a 50,000eO magnetic field.
134 Q Oe, as 142ksx/i.

The angle ratio was 0.548.

Examples 2 to 17 Component or amount of component f added to α-1.005: Changed as shown in Table i, and other drafting was performed in the same manner as in Example 1. The magnetic properties are shown in Table 1. Indicated. In Example 17 in the table, α-I was prepared by adding v' to the hydrochloric acid pickling waste solution! 'eoO
Dissolve Pe5o, -7H, O in water without line with H and make the first
'vI4!11!' under the same conditions as in Example 1 except as an iron salt solution and without adding ■. α-FeOO1 was used, V was added as NH4VO3 when adding N1, etc., and the other conditions were the same as in Example 1. Because of this, the amount of N2 supplied during the subsequent reduction was reduced to 1160 tAi (200 tAi).
The treatment was carried out in exactly the same manner as in Example 1, except that 7yeKtrH) was used. The nine metal magnetic powder obtained in this way is 50.0
Hc73QOe in a magnetic field of 006.

as l 3 f3 ICmu/, lit, angle ratio 0.
413 and nine.

Comparative Example 2 y・804・7BsO is dissolved in water to make a ferrous salt solution and α-Ha001K! Comparative example °1 except that the stock solution manufactured by No. 4 was used.
90 This metal magnetic powder was treated in the same manner as HCl1700 et in a magnetic field of 5000 oe.
as 143 Emu/p, square ratio 0.517 Examples 18 to 26 The same process as in Example 1 was carried out except that the amount of N2 supplied during the subsequent reduction was changed as shown in Table 2. The magnetic properties of the nine metal magnetic powders were as shown in Table 2 and Figure 6.

Comparative Examples 6-6 Processed in the same manner as in Comparative Example 2 except that the amount of N2 supplied during the subsequent reduction was changed as shown in Table 2. The magnetic properties of the metal magnetic powder thus obtained are as shown in Table 2 and Figure 6. 0 Examples 24 to 28 The treatment was carried out in the same manner as in Example 1 except that the reduction time in the latter stage was changed as shown in Table 6. The magnetic property values of the metal magnetic powder thus obtained were as follows. Comparative Examples 7 to 10 Comparative Example 2 except that the reduction time in the latter stage was changed as shown in Table 6 and the N2 supply amount was 1500 L/FeKf-H.
The magnetic properties of the metal magnetic powder thus obtained were as shown in Table 6 and Figure 4.

Table 1 Magnetic field 5oooooe Table II2 Magnetic field 50000e Table 6 Magnetic field s o o o o oe

[Brief explanation of the drawing]

Figure 1 is a 1-5000x electronic microscopic photograph of α-FeOOH prepared from Comparative Example 1 from the waste solution from hydrochloric acid pickling of iron plates. , α-1・00B0 prepared according to Example 1 added to 1e.
Figure 3 is a 15,000x magnified electronic ari photo!
In performing reduction after Dannetite, - supply rate N
The relationship between L/ 1'e 4・H and Hc is shown for the example @) and the comparative example (■). 0 Figure 4 shows the relationship between the reduction time from magnetite to metal and iio for the example (■) and comparative example (■). (Hr)

Claims (1)

[Claims] (1) In producing a metal magnetic powder whose main component is α-FeOOHtl-reduced, α-FeOOH
When producing B11, a vanadium compound was added to the first VC salt for neutralization, resulting in VtV of a -Fe0OHt.
Ni, co,
After processing to additionally attach one or more oxides or hydrates of Zn, Mn, Or, Oa, and Si, and optionally V compound wtl-, dehydration and reduction with an H2 gas stream. Method 0 for producing metal magnetic powder mainly composed of iron (21V-containing α-TPeOOHV
cn, i, co, Zn, Mn, Or. Oa, 8101 building or 2 or more oxides or hydrates or hydrates and, if necessary, a treatment to additionally attach V compounds 1-, ammonia pl-1t-8 to 10
%W! fRequired rangeMethod for producing metal magnetic powder containing #Ik as a main component described in item 10 (3) H2 cap supplied during dehydration and dehydration reduction to magnetite with a dehydration reduction temperature of 300 to 550°C P
60 Nt per hour or less per 1 kg of Fe, and the kiait supplied during subsequent reduction to metal is set to 90011 per hour or more per 1 kg of Fe. Method for producing metal magnetic powder 0