The main chemical composition of hematite is α-Fe2O3. Hematite is the main raw material of industrial iron-making, and its magnetic is weaker than magnetite while the flotability is better than magnetite processing. In industry, people always adopt crushing, magnetic separation, flotation separation, gravity separation or combine these ways to separate hematite, here is an introduction of hematite separating machine.
Take this hematite beneficiation process flow sheet as an example to generally introduce hematite separating machine. Same as other ores, after hematite ore being mined, hematite firstly will be crushed to 320~50mm by jaw crusher or gyratory crusher, then go through the process of middle crushing and fine crushing by cone crusher or jaw crusher and get the final products of 8~4mm. In the crushing process, some times there need magnetic separation and tailings removal, for example, Meishan hematite plant, its middle crushing product is divided into three particles sizes, and each one adopts low-intensity magnetic separation, high-intensity magnetic separation, gravity separation or combines these methods to removal tailings. After this process, crushed mines will directly go through two-stage closed circulation grinding beneficiation, and ball mill and hydrocyclone are used here. The magnetic beneficiation is between the first and the second stage grinding beneficiation and the main machine is vertical ring pulsating high gradient magnetic separator. Magnetic concentrate will be sent to the second grinding beneficiation by the slurry pump and the tailings are directly sent to the tailings reservoir.
There is a specific requirement for sulphur and phosphorus content in hematite beneficiation when carrying on the iron-making, and generally when getting concentrate after magnetic beneficiation people adopt reverse flotation to get rid of harmful elements in it. Mechanical agitation flotation cell and air-inflation mechanical flotation cell are always used in the reverse flotation beneficiation. After the flotation process, the iron concentrate will be sent to the concentration large well to go through concentration beneficiation, and thickeners used here are peripheral transmission thickener and center transmission thickener. The concentrated overflow is as to the backwater and the underflow will be sent to the filter workshop and through the filter to get the iron concentrate. Commonly used filters are a ceramic filter and disk vacuum filter.
Except for these machines, High-pressure roller mill and rotary kiln are sometimes used when talking about the hematite processing machines.