▎ 摘　　要

NOVELTY - Preparing water-dispersed graphene/magnetite composite powder, comprises: (a) ultrasonically dispersing the oxidized graphite and sodium polystyrene sulfonate in water at room temperature, forming a reaction solution, heating and reacting; (b) adding ferric salt and ferrous salt into the reaction solution under nitrogen atmosphere, adding aqueous ammonia, cooling, reacting, adding oleic acid and continuing to react; and (c) cooling to room temperature, collecting the graphene/magnetite composite powder by using a magnet, washing by using deionized water, drying to obtain the product. USE - The method is useful for preparing water-dispersed graphene/magnetite composite powder. ADVANTAGE - The method: is simple and suitable to achieve industrial production; and produces composite powder with small resistivity, high magnetizing strength and good dispersion property in water, where the magnetite crystal phase is pure and excellently compounded with the graphene, and has excellent dispersion property on the surface of the graphene and in the layer. DETAILED DESCRIPTION - Preparing water-dispersed graphene/magnetite composite powder, comprises: (a) ultrasonically dispersing the oxidized graphite and sodium polystyrene sulfonate having mass ratio of 1:5-1:20 in water at room temperature, forming a reaction solution, heating up to 90-110 degrees C, reacting for 8-16 hours, where the mass volume ratio of the oxidizing graphite to water is 5-200 mg:100 ml; (b) adding ferric salt and ferrous salt having mass ratio of 2.7-2.75:1 into the reaction solution under nitrogen atmosphere at room temperature, adding aqueous ammonia, cooling to 70-90 degrees C, reacting for 20-40 minutes, adding oleic acid and continuing to react for 80-100 minutes, where the mass ratio of the sum of the ferric salt and the ferrous salt is 1:1-1:5, the mass volume ratio of the ferric salt to aqueous ammonia is 0.73-0.75 g:2 ml, and the volume mass ratio of aqueous ammonia to oleic acid is 1 ml:0.0752-0.08 g; and (c) cooling to room temperature, collecting the graphene/magnetite composite powder by using a magnet, washing by using deionized water, drying to obtain the product.