salt of a carboxyl group and an alkali metal salt of a hydroxyl group to a water-based magnetic liquid comprising magnetic particles dispersed in an acidic water-based solvent to cause the magnetic particles to aggregate in the water-based mag› netic liquid; and 

collecting the aggregated magnetic particles to obtain the magnetic powder. 

In an embodiment, a compound the protic compound of which is of weaker acidity than acid contained in the acidic water-based solvent is employed as the alkali metal salt com- pound. 

In an embodiment, the alkali metal salt compound that has been adhered to a surface of the magnetic particles converts into a protic compound, resulting in the aggregation of the magnetic particles in the water-based magnetic liquid. 

In an embodiment, the alkali metal salt compound is an aromatic compound having the substituent. 

In an embodiment, the alkali metal salt compound is selected from the group consisting of an alkali metal salt compound of cinnamic acid and an alkali metal salt com- pound of dihydroxynaphthalene. 

A further aspect of the present invention relates to mag› netic powder manufactured by the above manufacturing method. 

A still further aspect of the present invention relates to a method of manufacturing a magnetic recording medium, which comprises: 

manufacturing magnetic powder by the above manufactur› ing method; 

dispersing the magnetic powder that has been manufac- tured together with an organic solvent and a binder to prepare a magnetic coating material; and 

forming a magnetic layer with the magnetic coating mate› rial that has been prepared. 

A still further aspect of the present invention relates to a magnetic recording medium manufactured by the above manufacturing method. 

The present invention can provide a magnetic recording medium in which microparticulate magnetic powder is dis› persed to a high degree, affording good electromagnetic char› acteristics. 

Further, since dispersion of the microparticulate magnetic powder is facilitated, the dispersion load on the magnetic particles in the manufacturing process can be greatly reduced. 

Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure. 

Unless otherwise stated, a reference to a compound or component includes the compound or component by itself, as well as in combination with other compounds or components, such as mixtures of compounds. 

As used herein, the singular forms "a," "an," and "the" include the plural reference unless the context clearly dictates otherwise. 

Except where otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." Accord› ingly, unless indicated to the contrary, the numerical param› eters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present inven› tion. At the very least, and not to be considered as an attempt 

## DETAILED DESCRIPTION OF THE EMBODIMENTS 

to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of significant digits and ordinary rounding conventions. 

Additionally, the recitation of numerical ranges within this specification is considered to be a disclosure of all numerical values and ranges within that range. For example, if a range is from about 1 to about 50, it is deemed to include, for example, 1, 7, 34, 46.1, 23.7, or any other value or range within the range. 

The following preferred specific embodiments are, there› fore, to be construed as merely illustrative, and non-limiting to the remainder of the disclosure in any way whatsoever. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for fundamental understanding of the present invention; the description making apparent to those skilled in the art how several forms of the present invention may be embodied in practice. 

An aspect of the present invention relates to a method of manufacturing magnetic powder, which comprises: 

adding an alkali metal salt compound comprising a sub› stituent selected from the group consisting of an alkali metal salt of a carboxyl group and an alkali metal salt of a hydroxyl group to a water-based magnetic liquid comprising magnetic particles dispersed in an acidic water-based solvent to cause the magnetic particles to aggregate in the water-based mag- netic liquid; and 

collecting the aggregated magnetic particles to obtain the magnetic powder. 

The present invention further provides the magnetic pow› der obtained by the above method. 

In the magnetic recording medium, the fact that the mag- netic particles are present in the form of microparticles in the magnetic layer relates to enhancing electromagnetic charac› teristics. Thus, to enhance electromagnetic characteristics, it is desirable for microparticulate magnetic particles to be present in the magnetic layer in a highly dispersed state. To that end, in the magnetic layer-forming coating liquid, it is desirable to disperse the microparticulate magnetic particles to a high degree. Through the above steps in the present invention, despite aggregating in the water-based magnetic liquid, it is possible to obtain a magnetic powder comprised of magnetic particles that can be readily dispersed to a high degree in an organic solvent-based magnetic layer-forming coating liquid. Accordingly, by subjecting the microparticu› late magnetic powder to the above steps, it is possible to obtain magnetic powder that is capable of forming a magnetic layer in which a microparticulate magnetic powder is dis› persed to a high degree. 

The method of manufacturing magnetic powder of the present invention will be described more specifically below. 

Preparation of Water-Based Magnetic Liquid 

The above "water-based magnetic liquid" refers to a liquid in which magnetic particles are in a state of dispersion, with› out precipitation or aggregation, to a degree where separation of the solid phase and liquid phase cannot be determined visually. One embodiment (referred to as the "first embodi- ment", hereinafter), can be obtained by simultaneously or sequentially admixing the water-based solvent, magnetic par› ticles (also referred to as the "starting material magnetic particles", hereinafter), and an acid component. From the perspective of suitability to the formation of a high-density recording-use magnetic recording medium, the starting mate› rial magnetic particles desirably have an average primary particle size of equal to or less than 35 nm. 

