Hematite is a weakly magnetic iron ore, occurring as single hematite, polymetallic-bearing hematite, or magnetite-hematite mixed ores. All types undergo a three-stage one-closed-circuit crushing process (jaw crusher for primary, cone crushers for secondary and tertiary) followed by ball milling to -200 mesh fines. However, the subsequent upgrading route must be customized according to the ore’s mineralogy and particle size.
For single hematite: Fine-grained or complex ores are best treated by magnetic roasting-magnetic separation. Coarse to medium grains (2-20 mm) respond well to gravity or high-intensity magnetic separation, while fine particles are often processed by flotation (direct or reverse). In practice, combined flowsheets of gravity-flotation-high-intensity magnetic separation are commonly used to balance recovery and concentrate grade.
For polymetallic-bearing hematite (with phosphorus or sulfides): Iron recovery is accompanied by flotation to separate phosphorous or sulfide minerals, typically using a combination of gravity, flotation, and high-intensity magnetic separation to co-recover iron and valuable associates.
For mixed magnetite-hematite (or siderite) ores: When no polymetallic elements exist, a low-intensity magnetic separation step recovers magnetite, while gravity, flotation, or high-intensity magnetic separation recovers the weakly magnetic fractions; direct magnetic roasting may also be an option. If polymetallics are present, the flowsheet becomes more complex, often starting with low-intensity magnetic separation and adding flotation and other methods in series for sequential recovery of iron and associated metals.
In all cases, there is no universal recipe – only a flexible, ore-specific combination of unit processes ensures economic and efficient beneficiation.
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