Flotation is a complex beneficiation process, which involves a variety of process factors and operational factors. How to ensure the stable and efficient operation of flotation stage is one of the important topics of flotation concentrators. Fodamon engineer concluded that the flotation production operation mainly includes the control of middling circulation, the judgment of the change of flotation foam properties, and the adjustment of flotation machine inflation and pulp level. In this article, we will teach you to master the flotation production operation from these three aspects.
a. Control of ore circulation in flotation
The circulating quantity of middling is an important factor in the flotation stage, which is directly related to the smoothness and stability of the flotation process. The circulating amount of medium ore should be determined according to the nature of ore. Generally speaking, ores with serious oxidation and alteration are easy to produce slime in the grinding stage. At this time, the minerals or conjoined bodies that have been separated from monomers in the middling are covered by slime, which will pollute the surface of mineral particles that have just entered the flotation operation. This kind of ore should choose open circuit flotation or reduce the circulation of middling during flotation.
The circulating amount of ore in flotation should generally be controlled within the range of 25% – 40%. Under the requirement of high recovery rate, the circulation volume can be appropriately increased. Under the requirement of higher concentrate grade, it is necessary to appropriately reduce the circulating amount of middling.
b. Judgement of the property change of flotation foam
The properties of flotation foam include the color of foam, the thickness of foam layer, the size of foam, the virtual and solid surface of foam, the annexation, stability, fluidity of foam, and the sound of foam scraping. From these properties, we can judge whether the ore washability is good or bad and whether other process conditions are suitable. Among them, the thickness of the foam layer is closely related to factors such as the amount of aeration and the dosage of reagents. Excessive thickness of the foam layer will reduce the recovery rate and improve the concentrate grade.
The observation of flotation foam state is to observe the changes of foam color, size and other states in the operation area of a stage of roughing, cleaning and scavenging. Take the foam layer in the first stage of roughing as an example. The foam layer in the first stage of roughing is generally thick, dark in color, uniform in size, and can flow smoothly. Foam is stable and non sticky. The color and thickness of foam in the operation area change significantly from the first tank to the last tank, and foam makes a swish when it scrapes into foam tank. At this time, the thickness of foam layer is generally between 100~300mm, and the thickness of foam layer in cleaning operation is between 300~500mm.
c. Adjustment of flotation machine inflation and pulp level
Air is one of the important media in flotation process. After sufficient aeration and reagent mineralization, the minerals in the pulp can form a stable flotation carrier foam. If the gas is inflated excessively, the oxidation degree of minerals will increase, which will reduce the floatability of minerals. Proper inflation can keep the foam layer in the flotation machine stable without turning over. The specific situation needs to be determined in combination with the operation performance of the flotation machine. Generally, medium or low inflation can effectively improve the flotation recovery.
For the self-priming flotation machine, except for the first cell feeding flotation machine, the air inlet pipes of other flotation machines operating in the same row cannot be closed. For large flotation machines, the adjustment of flotation machine inflation and pulp level should be mainly fine-tuning, so that a relatively thick foam layer and a stable foam area can be formed in the flotation machine. The thickness control of flotation foam layer in the first cell of roughing should be adjusted first, and other cells should be determined according to the actual production situation.
The above are the three major flotation production operations. The flotation operation is practical. Before the flotation operation, it is necessary to understand the performance and characteristics of the equipment in the flotation operation in detail, give full play to the advantages of the equipment, and achieve fast collection, early collection, fast collection and more collection, so as to improve the flotation separation index. In actual production, flotation operators need to observe repeatedly and analyze constantly to improve their identification ability.