Hematite beneficiation processes are customized according to ore properties: fine particles utilize roasting-magnetic separation, coarse grains employ combined gravity-magnetic methods, and silica removal is achieved through flotation. For polymetallic ores, integrated magnetic-flotation techniques recover both iron and sulfides, while siderite-magnetite mixtures primarily use weak magnetic separation with optional roasting or gravity refinement.
Hematite is a kind of weakly magnetic iron ore. It contains single hematite, polymetallic hematite and siderite-magnetite mixture.
Roasting magnetic separation is one of valid methods to separate fine from ultrafine particles (below 0.02mm). When the components are complicated and other beneficiation methods fail to meet related indicators, it is strongly recommended.
Flotation is common when separating fine from ultrafine hematite. There are two methods --- direct flotation and reverse flotation.
Gravity separation and strong magnetic separation are more suitable for the separation of coarse particle (2-20mm).
The use of specific beneficiation method and combined use shall observe types of ores.
The polymetallic hematite mainly refers to hydrothermal or sedimentary hematite and siderite which contains potassium and sulfide.
This kind of ore usually adopts gravity separation, flotation, strong magnetic separation, or combined separation methods to recycle the iron. Flotation is recommended to recycle the potassium and sulfide.
This kind of mineral has two separation methods. One is combined use of weak magnetic separation, gravity separation, flotation and strong magnetic separation where weak magnetic separation is responsible for recycling the magnetic iron ore while other methods are responsible for recycling the iron ore having weak magnetism. The other is the combining process of roasting magnetic separation and other separation methods.
The beneficiation method is complicated. Generally, weak magnetic separation and other separation methods would be connected to perform beneficiation.
