After liberation, from 20 century to the mid-1950s, China has successively developed dozens of flotation machines since copying the Michalis Noble flotation machine from the Soviet Union. They can be counted from mechanical flotation machine to inflatable mechanical flotation machine, from small type flotation machine to large-scale flotation machine, from coarse-grained sorting flotation machine to fine-grained sorting flotation machine, from common flotation machine to specialized flotation machine. The research work of these aspects all has made considerable progress, and various flotation machines have realized seriation that basically satisfies production requirements from different dressing plants. From the flotation machine’s application, it can be used in roughing, scavenging as well as concentration, some are used in pre-selected operation of the grinding and classification circuit. There are ladder layout and plane layout, especially the combined unit that has perfected the flotation machine and enhanced the special terrain configuration as well as the equipment renewal and adaptability of the old plant.
The working principles of the mechanical and air sell-priming flotation machine (including the impeller and stick wheeled flotation machine) are primarily the same: utilizing the negative pressure produced by the impeller or stick wheel during their rotation, inhaling air via the quill shaft and then diffusing to bubbles. Depending on the violent stirring and projection, the air bubbles are fully mixed with the ore pulp.
The chief difference between the impeller flotation machine and stick wheeled flotation machine basically lies in the inflatable equipment: the inflatable equipment of the impeller flotation machine is comprised of the impeller and the hydraulic cover (known as stator). Besides, the guide blade on the hydraulic cover is similar to the director of the centrifuge. Compared with the no-guide blade flotation machine, it increases the inspiratory capacity without additional electricity consumption. Moreover, the amount of the air flowing into the machine is related with the negative pressure created by the inbetween of the impeller and the stator. The negative pressure reaches its summit when the clearance between the impeller and the stator maintains from 6 to 10 mm. in order to control the amount of the inhalation, one can control the screw rod 9 to change the size of circulation port 8 so as to regulate the circulating ore pulp volume. Normally, the aeration quantity is maximal when the volume is one to two times the original volume.
The aeration equipment of the stick wheeled flotation machine consists of the oblique rod mill and boss. Due to its features, when rotating, the linear speed of the oblique rod mill becomes higher the lower of it, and this causes a rather violent stirring. The boss is installed under the oblique rod wheel, whose function is to prevent the pulp from forming eddy at the bottom of the oblique rod mill, ensuring the mixture of the ore pulp and the air to spread away along its back presented as “W” that has enlarged the vacuum degree of the oblique rod wheel area. Because the pulp rushes around the chute like a W shape, therefore there’s little dead space and the capacity utilization is high.