Hematite with higher phosphorus content is mostly shaped hematite. Its embedded granularity is fine, iron minerals and gangue minerals constitute granular, relatively weak magnetic, and the particle size distribution is not uniform, high phosphorus content, easy to mud in the process of grinding, it is difficult to select. At present, the commonly used high phosphorus hematite iron ore beneficiation process include: wet magnetic separation process, single flotation process, selective floculation and flotation process and a variety of combined processes derived on this basis, including strong magnetic flotation + antiflotation, selective flotation after flotation and flotation + reverse flotation and reduction roasting + magnetic separation + flotation and other processes.
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Magnetic separation process mainly uses the magnetic difference between red iron and gangue minerals. The greater the difference than the magnetization coefficient, the greater the magnetic difference between the minerals, and the qualified hematite is obtained by the wet strong magnetic separator to remove the phosphorus impurities.
The single flotation separation method is mainly based on antiflotation. In the flotation process, the agents, stirring, inflation and other operations are used to make the gangue minerals attached to the bubbles and scrape out with the foam, and the iron minerals are left in the tank.
Selective polyflotation is the use of different properties between mineral particles to make useful mineral selective aggregation, and then to separate iron minerals from phosphorus by antiflotation. This method is generally applicable, simple to operate, low cost and easy to apply in industrial production.
Strong magnetic separation-antiflotation process is to first conduct magnetic separation of the raw ore, and then conduct reverse flotation and dephosphorization of the magnetic flotation concentrate. Strong magnetic selection can be a lot of waste, so that the selection grade of reverse flotation to improve, at the same time has a good removal effect, for antiflotation to create a good selection conditions.
Strong magnetic separation is performed at 70%﹣0.074mm condition of grinding fineness, using the SLon high gradient magnetic separator.
Antiflotation is the reverse flotation of magnetic concentrate crude concentrate, using sodium carbonate as a regulating preparation, water glass as a dispersant, soluble starch as an inhibitor of iron mineral, sodium oleate as a gangue mineral (including phosphate-containing ore) trap, to complete iron concentrate flotation.
Under the condition of-0.74mm and 70% of the raw ore, after a thick sweep of magnetic separation, magnetic concentrate can get a fine iron concentrate of 54.70%, recovery rate of 79.44% and only 0.17%.
The process is to use sodium carbonate grouting, water glass as dispersant, and soluble starch as flocculant (also an inhibitor of iron minerals) to selectively flocculation, and then use no. 2 oil for flotation and sludge. After sludge, the slurry is counterflotation to obtain iron concentrate. This process can greatly reduce the amount of flotation agents such as soluble starch and sodium oleate, which greatly reduces the cost of flotation agents. At the same time, selective flocculation and flotation removal sludge does not need to rebuild the slurry, which can make the process more smooth.
The process is an improvement of the "magnetization roasting-weak magnetic separation" process. First, the roasting is heated to a certain temperature to convert it into iron minerals with strong magnetic properties, and then grinding-magnetic separation and dephosphorization. The iron concentrate with high iron grade and iron concentrate with low phosphorus content is obtained, but sometimes excessive Al2O3 in iron concentrate occurs.
Above is the high form of phosphorus hematite phosphorus iron removal in several common methods, in the actual dressing, due to the phosphorus degree of hematite, and other impurities mineral properties are different, so in the selection process, should first beneficiation test analysis, through test analysis results, the design of suitable hematite iron ore beneficiation process and custom conform to the actual situation of hematite iron ore beneficiation equipment.