We has discussed the unit operations that are used in a silica plant. These unit operations can be used in various combinations to achieve the desired end product based on the starting ore quality. Jaw crusher, cone crusher, sand making machine can be use in the processing.

Washing is the simplest and lowest cost method of cleaning silica sand. In some of the very pure deposits that are void of heavy minerals, high amounts of clay and silt, and no surface staining, washing is sufficient to produce acceptable grade product. It may be use SBM sand washing machine. In the process, water is added to the sand and is generally pumped to a cyclone for desliming. The movement of the slurry passing through the pump and pipeline is sufficient to loosen the small amount of fines or clay that are in the ore body. Once the minor amounts of fines or clay have been released from the silica sand they can be removed via a variety of methods.

High frequency screens supplied by companies like Derrick or Rotex are generally used to make the 0.5 mm separation. The latest developments are high capacity screens that can size 250 tph with one screen. The high capacity screens employ several screen decks within one machine unit. The system employees a feed distribution system that evenly feeds all screen decks simultaneously. Figure 6 shows a photograph of the screen produced by Derrick for this application.

The flotation process is primarily used to remove the iron bearing heavy minerals in glass sand. The minerals are generally the same as the iron bearing minerals described in the gravity section. At times, flotation can also be used to remove mica.

In North America, all glass sand is dried at the silica processing plant prior to shipping to the glass manufacturing plant. The advantage of dried sand to the glass producer is the better ability to accurately measure the batch ingredients, better material flow characteristics, and better mixing of batch ingredients. The cost to dry the sand, however, is borne by the producers of the silica sand. Drying is the single most expensive unit operation in the silica plant. As the cost of fuel continuously increases, it becomes more of a cost burden.