Sun. Jan 23rd, 2022

Why Do We Choose Rotary Dryers When It Comes to Processing Phosphates?

Phosphate Rock Drying

Preparing phosphate rock for further processing is done in a variety of ways. You can grind it, filter it, screen it, and do other nasty things to phosphate rock, but you will inevitably need to dry the material since nearly all pre-drying preparation methods are wet processes.

Advantages of the process

Phosphate-bearing rock is unusable without processing  rotary dryer  and drying. Rotary dryers allow for better and faster drying process while providing a significant amount of advantages for any manufacturer.


  • It is hard to work with wet materials. Reducing liquid content is pivotal for the safety of various processual operations.
  • Accretion is reduced significantly, as dry phosphate rock is less prone to clogging. This makes further processing much faster and more energy efficient. You also will need to worry less about build-up in general.


Phosphate fertilizers

You surely know how phosphate fertilizers look like and the vast majority of them are granulated materials. Granulation is a relatively simple technological process. Rotary granulators make material inside solidify and form small fractions that we call granules. This granules need further drying before shipping.

Removing all the liquid contents is highly important for manufacturers of phosphate fertilizers. Modern efficient packing materials are cloth bags, plastic bags, etc. In order to ensure optimal storing and transferring of the product, we need to remove moisture completely.

Animal Feeds

Phosphate rock is also pivotal for animal feeds manufacturers. After first stages of processing, animal feeds also need additional drying.

Granulated Phosphate Products

There are distinct upsides of using drying to process various granular products.


  • Higher product quality. Granules that are made with rotary granulators have rough shapes and prone to stick to each other without drying. In a rotary dryer, granules lose their liquid contents. At the same time, granules lose their edgy form as they are polished by constant rotations of the vessel. As a result, we receive a much better product.
  • Robust granules. During the drying process, granules lose moisture and harden. Their surface becomes harder and the product becomes less prone to caking. Simultaneously, granules gain resistance to mechanical damage and can be handled, transported, and applied without much care which is more than beneficial for both final users of the product and distributors.


Phosphate Dryers In Action

Phosphate processing is best described by two important characteristics: it demands robustness of equipment and large equipment capacity. Rotary dryers can efficiently solve both problems since they can sustain processing and ensure high output of dried product.

At the same time, rotary dryers are highly versatile and do not need any extensive pre-drying preparation of the material. This quality is more than beneficial since phosphate ore comes in a plethora of shapes and contains different amounts of liquid content.

Rotary dryers tumble the ore constantly revolving the vessel. The vessel is filled with hot air that flows in the same direction as particles inside the vessel. This system is often referred to as co-current configuration. Such systems ensure that previously granulated materials do not reach critical temperature which makes it less prone to self-abrasion. Simultaneously, granules do not lose their shape and gain hardness while losing moisture content. Co-current systems immediately remove wetness from granules’ surface and ensures slow even drying.

Additionally, rotary dryers are equipped with flights that constantly shuffle the material so that floating hot gases would dry it efficiently and without additional energy consumption.

Phosphates and Their Specifics

Phosphates are important ingredients in multiple industries and there are various difficulties related to processing them. When it comes to drying, we have to account for some material properties that may cause following issues:


  • Accretion. Most phosphate materials easily cluster and create clumps that make drying less efficient. Making sure that material build-up does not affect the process is crucial. Usually, rotary dryers are equipped with exterior knocking systems that remove accretion in the interior of the vessel through vibration.

Another elegant solution is using screw conveyors that feed material into the vessel with more momentum preventing it from clumping. Accretion is less likely to be an issue in vessels made of stainless steel and 2B finish. 


  • Abrasion. Phosphates wear down equipment fairly quickly and you need to ensure that some parts of the dryer need additional protection. Inlets and flights should be made of robust materials.
  • Dusting. Phosphate particles are extremely small and create a lot of dust. Very often working with phosphate rock is nearly impossible due to the amount of dust generated by the process. One of the best solutions is to have a collector dust bad incorporated in the system controlling emission. Dusting is one of the most problematic issues, but addressing it is the best way to reduce waste and ensure cleaner manufacturing process.

By admin

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