Roller Screen (RS)
Roller screen or RS is an equipment that is used for sizing and transfer of materials in the mining industry.
This equipment has a number of rotating rolls. The rotation cause the materials pass over them to be sized and transferred. In this equipment, the rolls are placed next to each other with a certain and adjustable distance so the materials pass through the space between them, while passing over the rolls, the sizing is also done at the same time.
Due to the nature of the rotation of the rolls and the gentle movement of the material on the rolls, roller screen can be used to transfer fragile materials with high humidity, while the vibrating conveyor cannot be used for this type of material.
Roller screens are divided into the following two types in terms of movement mechanism:
Multi drive roller screen
Single drive roller screen
In single drive roller screen, all rolls are connected to a gearbox using a chain and similar sprockets, while in multi drive roller screen, each roll is rotated by a separate gearbox. Fast and easy maintenance is the main advantage of multi drive roller screen over single drive roller screen , while single drive roller screen has smaller dimensions and less weight.
Roller screens are divided into the following three types in terms of operation mechanism:
Scalper
Classifier
Roller feeder
Scalper
This type of roller screen is used to separate additional materials such as stone, metal parts, returning pellets and plastic from ore concentrate. This equipment is usually used before the Balling Disc or before HPGR to prevent waste materials from entering them. In scalper, special polymer coatings with high impact and wear resistance are used for the rolls.
Classifier
These types of roller screens are usually used to separate fine materials, product concentrate and coarse materials. Fine materials are separated by the rolls of the first part of the equipment, the product is separated by the rolls of the second part of the equipment, and the coarse materials are directed to the end of the rolls and fall into the corresponding chute. Fine and coarse materials are transferred to the Balling Disc after passing through the crushing section. The product is also guided by a separate conveyor to the roller feeder located at the entrance of the furnace.
Roller feeder
This equipment is located at the entrance of the furnace. The product pellets prepared by sizing roller screen are guided to the roller feeder by a conveyor belt and are usually distributed on the roller feeder by a reciprocating conveyor belt. One of the goals of this equipment is to separate the fine pellets that are broken on the way to the roller feeder. But the main function is the uniform distribution of product pellets on the furnace surface. The length of the rolls roller feeder is usually 3.5 to 4 meters and can be increased up to 6 meters.
Roller screen rolls
FMS is specially focused on manufacturing rolls as the main part of roller screen. Depending on the application of the roller screen i.e. classification of raw iron ore pellets or the roller screen for collecting iron ore concentrate, special rolls have been designed by the company. Different rolls with different coatings have been successfully tested in real conditions in different pelletizing plants. Coating types are as follows:
Stainless steel 304
Stainless steel CA6NM
SF80 coating
AF190 coating
Advantages of FMS roller screens
Resistant coatings of AF190 rolls that increase the life of the rolls up to 2 years
Using the guard shaft in multi-drive roller screens by compensating for the high misalignment of the gearbox and roll axis instead of coupling
Uniform distribution of the concentrate on the surface of the roller screen in scalpers due to the installation of the spreader system
Using special polymer coatings with high resistance to impact and wear for roller screen rolls
Using the concentrate pressure system to the roll in scalpers in order to prevent the concentrate from entering the scalping section.
