High saturation and magnetic intensity magnetic powder and its preparing method and use

[0020] (1) Add the mixed solution of sodium hydroxide, ammonium bicarbonate and ammoniacal liquor into the ferrous sulfate solution, stir evenly, and adjust the pH value in the range of 12 to 14;

[0021] Wherein the concentration of ferrous sulfate solution is 0.8mol / L; The concentration of sodium hydroxide solution is 22%; The concentration of ammonium bicarbonate solution is 26%; The concentration of ammoniacal liquor is 31%; Sodium hydroxide: ammonium bicarbonate: the mass ratio of ammoniacal liquor is 1: 1: 1; the mixed solution of ferrous sulfate, sodium hydroxide, ammonium bicarbonate and ammonia water is mixed in a ratio of 1: 25 (mass ratio);

[0022] (2) Nitrogen is passed into the mixed solution of step (1), the temperature is raised to 65° C., and the temperature is kept for 20 minutes;

[0023] (3) After heat preservation, the temperature of the mixed solution in step (2) was raised to 82° C., the nitrogen gas was switched to the air, and the heat preservation reac

[0029] (1) Add the mixed solution of sodium hydroxide, ammonium bicarbonate and ammoniacal liquor into the ferrous sulfate solution, stir evenly, and adjust the pH value in the range of 12 to 14;

[0030] Wherein the concentration of ferrous sulfate solution is 0.6mol / L; The concentration of sodium hydroxide solution is 25%; The concentration of ammonium bicarbonate solution is 30%; The concentration of ammoniacal liquor is 35%; Sodium hydroxide: ammonium bicarbonate: the mass ratio of ammoniacal liquor is 1.5:1.2:2; the mixed solution of ferrous sulfate, sodium hydroxide, ammonium bicarbonate and ammonia water is mixed in a ratio of 1:50 (mass ratio)

[0031] (2) Nitrogen is passed into the mixed solution of step (1), the temperature is raised to 85° C., and the temperature is kept for 30 minutes;

[0032] (3) After the heat preservation, the temperature of the mixed solution in step (2) was raised to 90° C., the nitrogen gas was switched to the air, and the heat preservation

[0038] (1) Add the mixed solution of sodium hydroxide, ammonium bicarbonate and ammoniacal liquor into the ferrous sulfate solution, stir evenly, and adjust the pH value in the range of 12 to 14;

[0039] Wherein the concentration of ferrous sulfate solution is 1.0mol / L; The concentration of sodium hydroxide solution is 28%; The concentration of ammonium bicarbonate solution is 33%; The concentration of ammoniacal liquor is 30%; Sodium hydroxide: ammonium bicarbonate: the mass ratio of ammoniacal liquor is 3:1.5:2; the mixed solution of ferrous sulfate, sodium hydroxide, ammonium bicarbonate and ammonia water is mixed in a ratio of 1:75 (mass ratio)

[0040] (2) Nitrogen is passed into the mixed solution of step (1), the temperature is raised to 90° C., and the temperature is kept for 30 minutes;

[0041] (3) After heat preservation, the temperature of the mixed solution in step (2) was raised to 100° C., the nitrogen gas was switched to ventilate the air, and the heat preserva