![]() |
Geotechnical Engineering
|
![]() |
|
The University of North Florida |
Terry Parker High School |
Michelle (left) and Ashlie (right) and a friend visit Michler's Landing south of Ponte Vedre in northeast Florida to observe that wave action on the beach concentrates components of the sand. |
Sand components are concentrated by waves at the beach by particle size and shape and the specific gravity of the particles. |
![]() |
Concentration of heavy minerals by current action |
Iluka is located on Warner Road near Route 17 between Green Cove Springs and Palaka. |
Iluka's heavy mineral dry mill processing and administrative buildings as seen from Warner Road |
![]() |
Iluka is located in southern Clay County south of Green Cove Springs. To find Iluka's location on the map, look for the large O with a smaller 6 next to it. Then look to the left (west) across Route 17 south of the small airfield and east of the 118' elevation. Iluka is represented by a mine symbol (crossed pick axes) on the map. The mined lands are indicated by the rectangular pattern areas in light blue. |
![]() |
Iluka mines the heavy mineral sands using a dry method using large scraper equipment. The existing trees are clear cut and removed (most of the mining land is leased from lumber companies) . The topsoil is pushed off to the side of the mining area forming berms. The topsoil is saved and is used in reclaming the land after mining is completed. The topsoil retains the seeds of grasses and many plants so that only pine treees need to be planted after mining to return the land to its original condition. |
The sand is brought to the wet mill where it is mixed with water forming a "slurry" which is transported to the wet mill |
![]()
|
The wet mill consists of the aparatus on the left which removes the large "debris" such as rocks and other large objects and then sends the "slurry" to the aparatus on the right |
The sands are brought to the top of the large rotating cylinder on top which consists of mesh strainers which remove the large pieces |
The "slurry" is pumped up to the cylindrical distributers on top which allow gravity to feed the "slurry" to the spiral sections |
Michelle with Iluka's Mr. Ted Goodman who was our guide for the visit |
Michelle next to a set of spiral separators
|
The spiral separators work because the less dense minerals are flung to the outside of the turn and removed as "tailings" and the heavy minerals stay to the inside and are collected and sent the the next set of spiral separators |
![]() |
After processing the "slurry" numerous times through spiral separators the wet mill product consists of about 86% heavy minerals. The "tailings" consisting of lighter minerals (mostly quartz) is returned to the mined land and is covered with topsoil during the reclamation process. |
Iluka's Dry Mill (prosessing plant) |
The product from the wet mill is brought to the dry mill by large trucks. |
The first step at the dry mill is to rinse the concentrated heavy mineral sand with caustic soda to remove all organic components |
After rinsing with caustic soda, the concentrated heavy mineral sand is heated to remove the water for the next steps in the process |
The titanium oxide minerals which are conductors (Illmentite, Leucoxene, and Rutile) are separated by an high voltage electrostatic process. |
The non conductor minerals (Staurolite, Zircon, and Monazite) as well as any remaining nonconducter light light minerals such as quartz are also isolated with this process. |
The titanium oxide minerals are separated by a series of magnets. The Illmenite is separed first with weaker magnets as Illmenite contains the most iron. |
The Leucoxene is searated next by stronger magnets as Leucoxene has less iron than Illmentie. The leaves the Rutile which is pure titanium oxide and is nonmagnetic. |
Michelle inspects some of the equipment at the dry mill |
The non conductor minerals (Staurolite, Zircon, and Maonazite) are isolated by their different specific gravities by a combination of processes such as the shaker table on the left and more spiral separator stages in the far right.. |
These smaller spiral separator stages cotinue to refine the non conductor minerals. The most valuable non conductor product is zircon which is used by the ceramics industry. Stauolite is not produced as a product at Iluka but is produced at other mining operations and is used for sand blasting. The Monazite is composed of Thorium Phosphate. |
A settling tank is used to skim off any remaining quartz by injecting a slurry from the bottom of the tank upwards in to the tank. The less dense quartz sinks more slowly than the more dense minerals (Stokes Law) and can be rmoved at the top of the tank. |