JPH07126016A - Purification of ferrous-containing solution - Google Patents

Abstract

PURPOSE:To produce ferrous-containing solution of high purity which is used for the production of the starting powder for ferrite by spray-calcination. CONSTITUTION:In the purification of an acidic solution of a variety of metal salts including ferrous ion as a feedstock, metals constituting the solution are added to reduce the free acids and impurities and adjust the pH to 2.0 to 5.0. At the same time, the solution is exposed to an oxygen-containing gas to adsorb the impurities to the hydroxides formed. Then, other hydroxides including impurities separated with the filter press are added to the treated solution to effect more adsorption and the hydroxides are filtered to remove the remaining impurities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to purification of a raw material metal salt solution for producing a ferrite raw material powder by spray-roasting a metal salt solution.

[0002]

2. Description of the Related Art As a conventional method for purifying a ferrous iron-containing solution, as disclosed in JP-A-3-5324, an aqueous solution of ferrous chloride is neutralized with iron or an iron compound to free hydrochloric acid. After adjusting the pH to 2 to 5, it is contacted with oxygen or an oxygen-containing gas to oxidize 0.5 to 15% of iron in the solution into a precipitate containing ferric oxide as a main component, and the precipitate is There is known a method for producing iron oxide for a ferrite raw material, which is separated and made into a purified ferrous chloride aqueous solution and then roasted at a high temperature.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In Japanese Patent No. 324, there is a method in which metallic iron or an iron compound is added to a solution to reduce the free acid in the solution to produce ferric hydroxide, and impurities are adsorbed to this to remove by precipitation. However, in this method, impurities are still contained in the order of several tens of ppm, and when soft ferrite is manufactured by the raw material powder manufactured by this method, it is an obstacle factor when improving magnetic properties such as core loss and saturation magnetic flux density. It was one.

[0004]

[Means for Solving the Problems] In order to solve the above-mentioned problems, as a result of intensive development by the inventors, as a result, in order to reduce the free acid, the metal constituting the solution was added to the acid solution to form a solution. Free hydrochloric acid in the solution is reduced, pH is adjusted, and impurities are adsorbed on the hydroxide produced by contacting with oxygen-containing gas, and then the hydroxide removed by the field press containing the impurities used once is added. The present invention provides a method for purifying a solution in which most of the remaining impurities are adsorbed and removed by filtration.

The gist of the invention is to purify an acid solution of a multi-component metal salt containing ferrous iron which is a raw material solution in the step of producing a soft ferrite raw material powder by a solution roasting method. After adding the constituent metals to reduce the free acid and impurities to adjust the pH to 2.0 to 5.0 and adsorbing the impurities to the hydroxide produced by contacting with the oxygen-containing gas, the impurities are removed. A method for purifying a ferrous iron-containing solution is characterized in that the hydroxide removed by the filter press containing is added, impurities are further adsorbed to the hydroxide, and the remaining impurities are removed by filtering the impurities.

[0006]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a purification process diagram of a metal salt solution according to the present invention. As shown in FIG. 1, first, the iron chloride solution is added to the pH adjusting tank 1
In the pH adjusting tank 1, while the metal Mn and / or Zn is subsequently added and mixed by stirring to reduce the free acid in the iron chloride solution to adjust the pH to 2.0 to 5.0. Injecting oxygen-containing gas into the to generate iron oxide,
The hydroxide removed by the filter press after adsorbing the impurities was added thereto, and the mixture was stirred and mixed, and the remaining impurities were adsorbed, and subsequently, the undissolved Mn and / or undissolved Mn and / Alternatively, after removing Zn, it is sent to the filter press 3, while the removed undissolved Mn and / or Zn is sent to the pH adjusting tank 1 again, and M
Reuse as n source.

Further, impurities are removed in the filter press 3 and the purified iron chloride solution is sent to the component adjusting tank, where M
A raw material solution is manufactured by adding components constituting a multi-component solution of n and Zn, and then the solution is spray roasted in a roasting furnace and then a soft ferrite raw material powder which is a product is manufactured through a dust collector. . On the other hand, in the filter press 3, a part of the hydroxide removed is sent to the pH adjusting tank 1 to reduce the free acid and used as the soft ferrite raw material powder.

As described above, in order to reduce impurities in the iron chloride solution, not only the hydroxide produced by adjusting the pH and introducing the oxygen-containing gas from the solution but also the hydroxide removed by the filter press once used. Impurities are further reduced since the product is also used. As a result, the amount of impurities is smaller than that in the conventional case, a high-purity ferrite raw material composite oxide can be produced, and the hydroxide removed by the input filter press can be recycled and the work is easy.

[0009]

EXAMPLE A pre-purified iron chloride solution at 70 ° C. having a composition as shown in Table 1 has a Mn concentration of 10 times that of HCl.
(Including undissolved Mn generated from a coarse filter)
Is put in a pH adjusting tank, and the pH is adjusted to 4.0 by stirring and is brought into contact with an oxygen-containing gas to generate a hydroxide, which causes impurities to be adsorbed, and then filtered by a filter press to remove the impurities. Removed impurities including hydroxide
The component composition of the iron chloride-containing solution after being put into the H adjusting tank, further adsorbing impurities therein, and coming out through a coarse filter and a filter press is as shown in Table 1.
It can be seen that the impurities are well removed.

Comparative Example To the pre-purification iron chloride solution at 70 ° C. described in the Examples, Fe (scrap of cold-rolled steel sheet generated in an iron mill) was added in a purification tank in an amount corresponding to 10 times HCl molar concentration. , PH was adjusted to 4.0, and impurities were adsorbed together with iron oxide produced by contacting with oxygen-containing gas, and then the impurities were removed by applying a coarse filter and filter press. The composition of the solution is as shown in the comparative example in Table 1, and it can be seen that many impurities still remain. As a result, the amount of impurities is smaller than that in the conventional method, and it is possible to produce an extremely high-purity soft ferrite raw material composite oxide.

[0011]

[Table 1]

[0012]

As described above, by adsorbing impurities to the hydroxide produced in the acid solution as in the present invention, and further adding the hydroxide removed by the filter press, By adsorbing the remaining impurities to this and reducing the impurities in the solution, it is possible to produce a very high purity soft ferrite raw material composite oxide as compared with the conventional method, and it is removed by the filter press to be added. The hydroxide has an extremely excellent industrial effect such that it can be recycled and the work is easy.

[Brief description of drawings]

FIG. 1 is a diagram showing a purification process of a metal salt solution according to the present invention.

[Explanation of symbols]

 1 pH adjusting tank 2 Coarse filter 3 Filter press

Claims (1)

[Claims] 1. When refining an acid solution of a multi-component metal salt containing ferrous iron, which is a raw material solution in the step of producing a soft ferrite raw material powder by a solution roasting method, a metal constituting the solution is added. , Free acids and impurities to reduce p
After adjusting the H2.0 to 5.0 and adsorbing the impurities to the hydroxide produced by contacting with the oxygen-containing gas, the hydroxide removed by the filter press containing the impurities is added, and A method for purifying a ferrous iron-containing solution, characterized in that the remaining impurities are removed by further adsorbing impurities to the solution and filtering this.