Method of making a magnetic powder

Claim 1

In a method for the catalytic reduction of cobalt ions in aqueous solution, the improvement which comprises the step of heating a solution at a temperature ranging from about 20° C. below such solution's boiling point up to its boiling point for a time at least sufficient to form a precipitate of magnetizable particles, such solution comprising on a 100 weight percent total solution basis: (A) from about 0.5 to 10 weight percent of at least one water soluble dissolved cobalt salt, selected from the group consisting of cobalt sulfate, cobalt chloride, cobalt bromide, and cobalt sulfonate, (B) from about 0.5 to 10.0 weight percent of at least one water soluble dissolved reducing agent selected from the group consisting of alkali metal hypophosphites, hydrazine hydrate, hydrazine hydrochloride, and hydrazine sulfate, (C) from about 0.0001 to 0.02 weight percent of at least one water soluble dissolved metal salt catalyst wherein the metal is selected from the class consisting of Group VIII-B and Group I-B of the Periodic Table of the Elements, (D) from about 0.1 to 3.0 weight percent of at least one water soluble dissolved globular protein selected from the group consisting of albumin and hemoglobin, (E) sufficient water soluble dissolved base alkali metal hydroxide to produce in said solution a pH ranging from about 7.0 to 13.5, and (F) from about 65 to 95 weight percent water, the weight ratio of dissolved cobalt to all other dissolved metals in such solution being in the range from about 1:10 to 1:1, said heating being conducted in the presence of a magnetic field having a field strength of from about 50 to 5000 oersteds, such solution having been prepared by the steps of (a) preparing a first solution comprising on a 100 weight percent total first solution basis: (1) from about 0.5 to 10 weight percent of said cobalt salt, (2) from about 0.5 to 10.0 weight percent of said reducing agent, (3) from about 0.1 to 3.0 weight percent of said protein, (4) sufficient of said alkali metal hydroxide to produce in said first solution said pH, and (5) from about 65 to 95 weight percent of said water, (b) preparing a second solution comprising on a 100 weight percent total second solution basis: (1') from about 0.01 to 10 weight percent of said metal salt catalyst, and (2') from about 65 to 95 weight percent of said water, and (c) admixing said first solution with said second solution and adding to the resulting solution sufficient of said alkali metal hydroxide to produce said pH in such resulting solution, the relative ratio of said first solution to said second solution being such as to produce in such resulting solution a composition corresponding to such solution.