In the iron ore beneficiation process, the current single gravity or magnetic separation process sometimes fails to produce qualified iron concentrate, especially the fine disseminated iron ore. The concentrate products obtained from gravity or magnetic separation are often subject to flotation treatment. The main flotation processes of iron ore include cationic reverse flotation and anionic positive flotation. In this paper, Fodamon engineers will mainly discuss the factors affecting iron ore flotation.
The floatability of different iron ores is quite different. For example, the floatability of magnetite is far worse than that of hematite, and the flotation reagents used for different types of iron ores are also different. In addition, the concentration will also affect the flotation of iron ores. Therefore, this paper selects three aspects as the analysis focus: iron ore type, flotation environment, and flotation reagents.
A. Impact of iron ore type
There are many and complex types of iron ores. At present, the industrial iron ores that can be used include: magnetite, hematite, magnetite, ilmenite, etc. Due to the large differences in the floatability of these iron ores, the selection of flotation type will be affected. Among iron ores, hematite, pseudohematite, limonite and siderite have good floatability. The coarse hematite is usually treated by reverse flotation, while the fine hematite can be treated by positive flotation.
The floatability of fake hematite is slightly worse than that of hematite, but both positive and negative flotation processes can be used to treat fake hematite. The floatability of siderite is similar to that of pseudohematite, and it is also a kind of ore that can be used in both positive and negative flotation. The reverse flotation effect of the two kinds of iron ores is better than that of the positive flotation. For magnetite with poor floatability, reverse flotation is generally used to flotation gangue minerals in iron concentrate, which can greatly reduce the impurity content in the concentrate.
Water-bearing iron oxide minerals are troublesome because they are hydrophilic, soft and easy to be slimed. The use process is different for different kinds of minerals, which depends on the nature of the ore itself.
B. Impact of iron ore flotation environment
The flotation environment here mainly refers to the change of PH value. Different iron ores have different requirements for PH value, and different PH will also affect the recovery rate.
Hematite and pseudohematite have strict requirements on the PH value. Too high or too low will cause the recovery rate to fluctuate. The appropriate PH value range of hematite is between 6.5 and 7.5, while the appropriate PH value range of pseudohematite is between 7 and 8. The selection of flotation process of siderite will change in different acid and alkali environments. In strong alkaline environments, siderite can choose cationic collectors for flotation, and in neutral media, anionic collectors can be used for collection.
C. Impact of iron ore flotation reagents
In terms of reagents, the commonly used flotation reagents for iron ore include cationic collectors, anionic collectors, inhibitors, etc. Among them, cationic collectors often use ether amine collectors to collect quartz and silicate in iron ores. Because of their relatively simple nature, low requirements on water quality and low temperature resistance, they are often used in flotation of iron ores. There are also many kinds of reagents, such as oxidized amine, coconut oil primary amine, soybean oil amine, etc.
The anionic collectors used to collect iron minerals include fatty acids, fatty acid soaps, sulfated soaps, etc. Relatively speaking, the selectivity is not as good as that of cationic collectors, and the requirements for PH value are relatively strict, and inhibitors are often used together to inhibit gangue minerals. When conducting anionic positive flotation, it is also necessary to select activator according to different ore properties. The common activator here is calcium oxide, which can make iron silicate minerals be flotation by organic acid. The commonly used inhibitor for iron ore is starch, and the specific use of the agent shall be determined according to the test after the ore property is proved.
The above are some influencing factors of iron ore flotation. In combination with the above analysis, we can find that due to the complex nature of iron ore, different ore types have different processing methods. In the actual application and production of each mine owner, it is also necessary to select the corresponding process flow according to the different properties of iron ore after the test is completed, according to the experimental results, to achieve a good recovery effect.