The invention provides a method for the bulk flotation of chilled converter slags and slowly-cooled electric furnace slags. The method comprises the following steps: first, separately sorting scrap copper and white matte from the chilled converter slags and the slowly-cooled electric furnace slags, carrying out coarse crushing treatment after mixing the materials according to a certain ratio, and then, carrying out crushing and sieving; carrying out classification after milling ores with qualified granularity by a stage-I mill, after classification and sand settlement, returning the stage-I mill for remilling, and carrying out classification; carrying out classification again after ore pulp overflows and enters a stage-II mill, carrying out flotation on the overflowing ore pulp, and after sand settlement, remilling by the stage-II mill; changing the adding position of a chemical agent; directly adding the chemical agent into a sand pump tank, ensuring the full reaction of the chemical agent and the ore pulp, and adjusting the usage of the flotation chemical agent in order to ensure ore dressing technical indexes; and as a result of the improvement of a flotation technology, directly producing qualified copper concentrates by the former two tanks of a rough flotation machine I, and starting a fine flotation machine III at a proper time, thereby ensuring that flotation products meet smelting requirements. The method is simple and easy to realize, is convenient to mount and operate, is great in indexes, is low in investment fees, is safe and practical, can effectively increase the recycling rate of slag flotation copper and the grade of the copper concentrates and is widely suitable for copper slag flotation industry.