Taconite Ore Mining Process
Crushing & screening equipment, separation equipment for taconite processing plant

Processing of taconite consists of crushing and grinding the ore to liberate iron bearing particles, concentrating the ore by separating the particles from the waste material (gangue), and pelletizing the iron ore concentrate.

Liberation is the first step in processing crude taconite ore and consists mostly of crushing and grinding.

The ore must be ground to a particle size sufficiently close to the grain size of the iron-bearing mineral to allow for a high degree of mineral liberation. Most of the taconite used today requires very fine grinding. Prior to grinding, the ore is dry-crushed in up to six stages, depending on the hardness of the ore. One or two stages of crushing may be performed at the mine prior to shipping the raw material to the processing facility. Gyratory crushers are generally used for primary crushing, and cone crushers are used for secondary and tertiary fine crushing.

Intermediate vibrating screens remove undersize material from the feed to the next crusher and allow for closed-circuit operation of the fine crushers. After crushing, the size of the material is further reduced by wet grinding in rod mills or ball mills. The rod and ball mills are also in closed circuit with classification systems such as cyclones. An alternative to crushing is to feed some coarse ores directly to wet or dry semiautogenous or autogenous grinding mills (using larger pieces of the ore to grind/mill the smaller pieces), then to pebble or ball mills. Ideally, the liberated particles of iron minerals and barren gangue should be removed from the grinding circuits as soon as they are formed, with larger particles returned for further grinding.

Taconite ore crushing and screening process:

Taconite ore is hauled to a primary crusher. The primary crusher reduces the taconite ore to a face powder consistency and the iron extracted magnetically, then the iron separated out through gravity and flotation processes

Crushing Oversized Taconite Pebbles in the VSI crusher

The VSI crusher's unique autogenous crushing and grinding action has been very successful in crushing the extremely hard oversize pebbles from the mill, thus increasing the capacity of the entire circuit.

The VSI crusher uses a unique rock-on-rock crushing process. This crushing action grinds and mills the feed material to produce a fine product with no contamination from wear parts. As the material fed into the VSI grinds and impacts against itself, the typical wear cost per tonne of material processed is very low.

The heavy duty VSI crusher can accepted new feed -35 + 6.6mm, and produce -6mm.

Taconite ore mining process

Taconite mining process involves crushing the rock to a fine-grain size, then mechanically removing the iron minerals from the waste material, grinding the taconite ore into marble size pellets.

Taconite ore is hauled to a primary crusher where it is crushed and further processed, thereafter conveying it to a crushed taconite ore surge stockpile. From the stockpile, the crushed taconite ore is then conveyed into the concentrator where the taconite ore are further crushed and ground through secondary crushing and grinding mills until the taconite ore reaches face powder fineness.

The purpose for the crushing and grinding of the taconite ore to this degree is to liberate or free the iron particles (magnetite) from the gangue (waste). The magnetic iron concentrate would then be made into taconite pellets, referred to as “taconite concentrate”, the operation will produce Taconite pellets used in steelmaking.

Milling process: Primary crusher -> Primary crusher return conveyor transfer -> Secondary crushing line -> Secondary crusher return conveyor transfer -> Tertiary crushing -> Tertiary crushing line -> Tertiary crushing line discharge conveyor -> Screening -> Grinder feed -> Primary grinding -> Classification -> Magnetic separation -> Secondary grinding -> Conveyor transfer to concentrator -> Concentrate storage -> Bentonite storage -> Bentonite transfer to blending -> Bentonite blending -> Green pellet screening -> Chilp regrinding -> Grate/ klin furnace feed

Taconite ore

Taconite ore is a very hard, tough, sticky and abrasive ferruginous (containing iron) rock that requires extensive processing to liberate the iron, which is then concentrated and made into pellets containing about 65% iron that are ultimately used in the steelmaking process.

The taconite ore processing industry produces usable concentrations of iron-bearing material by removing nonferrous rock (gangue) from low-grade ore.

Also See

• Iron ore processing for blast furnace
• Hematite ore crushing process
• Iron ore crushing plant

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