When considering an industrial agglomeration solution for a material, most focus is placed on what agglomeration equipment will yield the desired characteristics of the final product. While these are vital primary considerations, an equally important concern should be how to pre-condition a material for the desired agglomeration process. Pre-conditioning is essential, because it prepares material for other processing steps, and in doing so, assists in creating the best final product possible.
Pre-Conditioning Benefits
Many different materials benefit from pre-conditioning – even material that does not undergo agglomeration. Besides creating an optimal final product, pre-conditioning provides the following advantages in a pelletizing plant:
Easier Processing and Handling
Each step in the agglomeration process works to make the next step easier. Pre-conditioned material provides an early advantage to the entire process, resulting in easier handling for all subsequent steps.
Improved Product Control
Pre-conditioned material enhances size control and the ability to create a uniform product. In fact, numerous issues can be avoided by gaining greater control of the overall size of the material. For example, size control can reduce excessive recycle of small (unders) or large (overs) pellets. This improved control ultimately results in a better final product.
Increased Production
By creating an easy-to-handle material, pre-conditioning creates a consistent feedstock, permitting increased production rates versus an unconditioned material.
Pre-Conditioning Equipment
Once the final product result is determined, the required level of pre-conditioning should be evaluated in order to ensure a material will achieve the desired results. In addition to being able to test and define the type of pre-conditioning required, FEECO manufactures a variety of equipment that provides pre-conditioning benefits.
Rotary Dryer
Rotary dryers reduce moisture in a material using a rotating drum with customized lifting flights. As material travels down the drum, it cascades off the flights and comes in direct contact with a heated air stream that effectively dries the material. Because moisture is critical to the agglomeration process, material at or near its critical moisture requires drying before being agglomerated. Using a rotary dryer to reduce moisture allows for the addition of a binder during pelletizing and improves the desired tackiness necessary for pellet growth.
Paddle Mixer
Pugmill mixers, also called ‘paddle mixers’, use paddles to create a kneading and shear action as material travels through its barrel-shaped trough. These mixers provide pre-conditioning benefits such as wetting, standard mixing, granulating, and back mixing dried material (recycle) into the process.
Pin Mixer
Pin mixers use pins mounted on a rotor shaft to deliver pre-conditioning benefits such as standard mixing, granulating, and back mixing dried material into the process. As the pins rotate at a high velocity, the turbulent agitation forces imparted on the material also deliver densification. The use of a pin mixer as a pre-conditioning method is especially common in limestone pelletizing operations.
Testing Pre-Conditioning Methods
The most suitable approach to pre-conditioning is often determined through tests, such as those conducted in the FEECO Innovation Center. In this feasibility and pilot plant, experts are able to evaluate different methods of pre-conditioning to determine which approach best suits the process and product goals.
After successful feasibility testing, continuous-loop testing for agglomeration with pre-conditioning and drying can be tested to provide the data necessary for process scale-up, de-risking the path to commercialization.
Conclusion
FEECO has been a leader of agglomeration and pre-conditioning systems since 1951. Unmatched experience and the ability to blend knowledge across industries, paired with our extensive testing capabilities gives us the expertise to create the best process for your material from start to finish. For more information on material pre-conditioning for pelletizing processes, contact us today!