Three Main Points of Flotation Separation Operation

01Ore circulation amount control

Medium ore circulation is an important factor in the flotation stage. This factor is directly related to the smoothness and stability of the flotation process. The amount of medium ore circulation is determined according to the nature of the ore. Generally speaking, ore with severe oxidative alteration is prone to produce sludge during the grinding stage. At this time, the minerals or conjoined bodies in the medium ore that have been dissociated from monomers are covered with ore slime, which will contaminate the surface of the optional mineral particles that have just entered the flotation operation. This kind of ore should choose open-circuit flotation or reduce the circulation volume of medium ore during flotation.

The amount of flotation ore circulation is generally controlled within the range of 25% to 40%. Under higher recovery requirements, the amount of circulation can be appropriately increased. Under higher concentrate grade requirements, it is necessary to appropriately reduce the amount of medium ore circulation.

02Flotation foam properties judgment

Flotation froth properties include froth color, froth layer thickness, froth size, froth surface solidity, froth annexation, stability, fluidity, and froth scraping sound. From these properties, it is possible to judge whether the selectivity of the ore is good or not and whether the control of other process conditions is appropriate. Among them, the thickness of the foam layer is closely related to factors such as the amount of inflation and the dosage of medicine. Too thick foam layer will result in lower recovery rate and higher concentrate grade.

The observation of the state of the flotation foam is to observe the state changes of the color and size of the foam in the operation area of the roughing stage, the selection stage and the sweeping stage. Here is an example of a foam layer in a roughing stage. The foam layer in a roughing stage is generally thicker, darker in color, uniform in size, able to flow smoothly, and the foam is stable and non-stick. The color and thickness of the foam in the working area have obvious changes from the first tank to the last tank, and there is a swishing sound when the foam is scraped into the foam tank. At this time, the thickness of the foam layer is generally between 100~300mm, and the thickness of the foam layer in the selection operation is between 300~500mm.

03Adjustment of inflation volume and slurry level

Air is one of the important media in flotation process. After sufficient aeration and chemical mineralization, the minerals in the pulp can form stable flotation carrier foam. Excessive aeration will lead to increased mineral oxidation, thereby reducing the buoyancy of the mineral. Proper aeration volume can keep the foam layer in the flotation machine stable without turning over. The specific situation needs to be determined in combination with the operating performance of the flotation machine. Generally, medium or low aeration volume is used, which can effectively improve the flotation recovery rate.

For the self-priming flotation machine, except for the first tank feeding flotation machine, the air intake pipes of other flotation machines operating in the same row cannot be completely closed. For large flotation machines, the adjustment of the air volume and slurry level of the flotation machine should be mainly fine-tuning, so that a thicker foam layer and a stable foam area can be formed in the flotation machine. The thickness of the flotation foam layer in the first tank of roughing should be adjusted first, and the other tanks should be determined according to the actual production situation.

The above are the three major flotation separation operations. The flotation operation is practical. Before the flotation operation, the performance and characteristics of the equipment in the flotation operation should be understood in detail, and the advantages of the equipment should be exerted to achieve fast harvesting, early harvesting, and fast harvesting and more harvesting, so as to improve the flotation separation index. In actual production, flotation operators need to observe and analyze continuously to improve their own judgement ability.